+publisher:"Penn State University" +contributor:("Kon Well Wang, Committee Member")

You searched for +publisher:"Penn State University" +contributor:("Kon Well Wang, Committee Member"). Showing records 1 – 15 of 15 total matches.

▼ Search Limiters

Penn State University

1. Mahdavi, Arash. Mechanics Of Low-dimensional Carbon Nanostructures: Atomistic, Continuum, And Multi-scale Approaches.

Degree: 2012, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/14502

► A new multiscale modeling technique called the Consistent Atomic-scale Finite Element (CAFÉ) method is introduced. Unlike traditional approaches for linking the atomic structure to its… (more)

▼ A new multiscale modeling technique called the Consistent Atomic-scale Finite Element (CAFÉ) method is introduced. Unlike traditional approaches for linking the atomic structure to its equivalent continuum, this method directly connects the atomic degrees of freedom to a reduced set of finite element degrees of freedom without passing through an intermediate homogenized continuum. As a result, there is no need to introduce stress and strain measures at the atomic level. The Tersoff-Brenner interatomic potential is used to calculate the consistent tangent stiffness matrix of the structure. In this finite element formulation, all local and non-local interactions between carbon atoms are taken into account using overlapping finite elements. In addition, a consistent hierarchical finite element modeling technique is developed for adaptively coarsening and refining the mesh over different parts of the model. This process is consistent with the underlying atomic structure and, by refining the mesh to the scale of atomic spacing, molecular dynamic results can be recovered. This method is valid across the scales and can be used to concurrently model atomistic and continuum phenomena so, in contrast with most other multi-scale methods, there is no need to introduce artificial boundaries for coupling atomistic and continuum regions. Effect of the length scale of the nanostructure is also included in the model by building the hierarchy of elements from bottom up using a finite size atom cluster as the building block. To be consistent with the bravais multi-lattice structure of sp2-bonded carbon, two independent displacement fields are used for reducing the order of the model. Sparse structure of the stiffness matrix of these nanostructures is exploited to reduce the memory requirement and to speed up the formation of the system matrices and solution of the equilibrium equations. Applicability of the method is shown with several examples of the nonlinear mechanics of carbon nanotubes and carbon nanocones subject to different loadings and boundary conditions. This finite element technique is also used to study the natural frequencies of low-dimensional carbon nanostructures and comparing the results with those of a homogenized isotropic continuum shell. Conclusion is that, replacing the atomic lattice with an isotropic continuum shell for a graphene sheet does not significantly affect the vibration frequencies while in the case of carbon nanotubes and carbon nanocones there is a significant difference between the natural frequencies of the atomistic model and its continuum counterpart. In the case of the carbon nanotube, continuum model successfully captures the beam bending vibration modes while overestimating frequencies of the modes in which the cross-section undergoes significant deformation. Furthermore, in the case of carbon nanotubes, the continuum shell exhibits a torsional mode which appears to be an artifact resulting from the small nominal thickness typically used in the continuum shell approximation of these… Advisors/Committee Members: Eric M Mockensturm, Dissertation Advisor/Co-Advisor, Eric M Mockensturm, Committee Chair/Co-Chair, Dr Kon Well Wang, Committee Member, Panagiotis Michaleris, Committee Member, Mary I Frecker, Committee Member, Vincent Henry Crespi, Committee Member, Karen Ann Thole, Special Member.

Subjects/Keywords: Finite Element; Nanomechanics; Carbon Nanotube; Multisclae; Nonlinear; Continuum Mechanics

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mahdavi, A. (2012). Mechanics Of Low-dimensional Carbon Nanostructures: Atomistic, Continuum, And Multi-scale Approaches. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/14502

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mahdavi, Arash. “Mechanics Of Low-dimensional Carbon Nanostructures: Atomistic, Continuum, And Multi-scale Approaches.” 2012. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/14502.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mahdavi, Arash. “Mechanics Of Low-dimensional Carbon Nanostructures: Atomistic, Continuum, And Multi-scale Approaches.” 2012. Web. 04 Mar 2021.

Vancouver:

Mahdavi A. Mechanics Of Low-dimensional Carbon Nanostructures: Atomistic, Continuum, And Multi-scale Approaches. [Internet] [Thesis]. Penn State University; 2012. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/14502.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mahdavi A. Mechanics Of Low-dimensional Carbon Nanostructures: Atomistic, Continuum, And Multi-scale Approaches. [Thesis]. Penn State University; 2012. Available from: https://submit-etda.libraries.psu.edu/catalog/14502

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

2. Zhao, Haiyu. Passive, Iterative, and Repetitive Control for Flexible Distributed Parameter Systems.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/6805

► Many engineering structures have distributed parameter models governed by partial differential equations. Without damping, distributed flexible structures are not stable due to the infinite number… (more)

▼ Many engineering structures have distributed parameter models governed by partial differential equations. Without damping, distributed flexible structures are not stable due to the infinite number of resonances at natural frequencies. Bounded sinusoidal inputs at these frequencies can cause unbounded response. This thesis shows that Passive Control, Iterative Learning Control (ILC), and Repetitive Learning Control (RLC) can be designed to reduce tracking or regulation errors in response to bounded, periodic inputs. Distributed flexible strings, beams, membranes, plates, axially moving materials, electrostatic microbridges, and flexible whisker contact imagers are studied. Passive control using distributed or boundary damping is proven to stabilize the response of strings, beams, membranes, and plates. Damping ensures bounded response to bounded distributed and boundary inputs. Distributed viscous or Kelvin-Voigt material damping can guarantee pointwise or strong boundedness for strings and beams and weak boundedness for membranes and plates. Translational damping on one boundary stabilizes strings and beams. Damping on part of the boundary can also weakly stabilize the forced response of membranes and plates, provided the damped and undamped boundary normals satisfy certain conditions. For example, damping on half and one side of the boundary is sufficient for circular and rectangular domains, respectively. Iterative Learning Control provides precise tension and speed control of axially moving material systems to enable high speed processing of paper, plastics, fibers, and films. PD tension/speed control is proven to ensure strong and weak boundedness of distributed displacement and tension, respectively, in a single span axially moving material system. ILC provides the same theoretical result with half the speed error and 30% of the tension error of PD control using the same control effort. Repetitive Learning Control is applied to an electrostatic microbridge and a repetitive contact imager. Electrostatic microactuators are used extensively in MEMS sensors, RF switches, and microfluidic pumps. Due to high bandwidth operation, however, reduction of residual vibration using feedback control is difficult to implement. Feedforward RLC is designed, proven stable, and simulated for an electrostatic microbridge under a periodic desired spatial/time trajectory. High residual stresses in the microbridge mean that bending stiffness can be neglected and a pinned string model with uniform loading is appropriate. Squeeze film damping ensures boundedness of the distributed transverse displacement. Offline RLC processing of the average displacement as measured by capacitive sensing updates a waveform generator's parameters. Simulations show a 36% reduction in midspan overshoot under repetitive control. Repetitive contact imaging uses a flexible whisker attached to a two axis robot through a load cell. Assuming small deformations and rotations, the pitch axis decouples from yaw. The yaw axis, under PD control, sweeps… Advisors/Committee Members: Christopher Rahn, Committee Chair/Co-Chair, Kon Well Wang, Committee Member, Qian Wang, Committee Member, Farhan Gandhi, Committee Member.

Subjects/Keywords: Feedforward control; flexible distributed parameter systems; vibration control; BIBO stability

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zhao, H. (2008). Passive, Iterative, and Repetitive Control for Flexible Distributed Parameter Systems. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/6805

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zhao, Haiyu. “Passive, Iterative, and Repetitive Control for Flexible Distributed Parameter Systems.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/6805.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zhao, Haiyu. “Passive, Iterative, and Repetitive Control for Flexible Distributed Parameter Systems.” 2008. Web. 04 Mar 2021.

Vancouver:

Zhao H. Passive, Iterative, and Repetitive Control for Flexible Distributed Parameter Systems. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/6805.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhao H. Passive, Iterative, and Repetitive Control for Flexible Distributed Parameter Systems. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/6805

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

3. Howard, Anna Kathleen Tyler. The Aeromechanical Stability of Soft-Inplane Tiltrotors.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/5861

► A soft-inplane tiltrotor can be subject to the aeromechanical instabilities of ground and air resonance in addition to whirl flutter. While whirl flutter has been… (more)

▼ A soft-inplane tiltrotor can be subject to the aeromechanical instabilities of ground and air resonance in addition to whirl flutter. While whirl flutter has been studied by many researchers, air and ground resonance in a tiltrotor has not been explored thoroughly. This dissertation investigates the aeromechanical instabilities of air and ground resonance in a tiltrotor and to assess some passive methods for improving the stability of a soft-inplane tiltrotor. This research is broken into two parts, addressing the semi-span model and the full-span model. In the first chapters, a semi-span analytical model consisting of a rigid blade rotor coupled to a rigid pylon and an elastic wing is developed and validated. The Boeing Model 222 which was wind-tunnel tested in 1972 is used to validate the current analytical model. This aircraft is used as the baseline for the analytical investigation of ground resonance and air resonance in hover, air resonance in transition, and air resonance and whirl flutter in airplane configuration. Neither ground resonance nor air resonance in hover are predicted for the Model 222 though air resonance in transition and cruise as well as whirl flutter at high speeds are predicted. Aeroelastic couplings in the rotor blades and wing are shown to affect the air resonance stability in cruise and transition and to be useful in augmenting the inherent stability of the aircraft. Wing vertical bending coupled to wing torsion and rotor low frequency lag coupled to blade torsion were helpful for air resonance. However, the rotor coupling was quite detrimental to whirl flutter stability and the wing coupling was unable to stabilize all the air resonance regions completely. The second part of the thesis expands the semi-span model to full-span: fuselage pitch and roll motion, anti-symmetric wing motion, and the second rotor motion are added. The full-span model determined that fuselage motion can couple with rotor low frequency lag to exhibit air resonance. The ground resonance case was stable for the full-span model but showed only a small margin of stability, indicating that a ground resonance instability is possible with a tiltrotor. Advisors/Committee Members: Farhan S Gandhi, Committee Member, Kon Well Wang, Committee Member, George A Lesieutre, Committee Member, Edward C Smith, Committee Chair/Co-Chair.

Subjects/Keywords: full-span; whirl flutter; semi-span; civil tiltrotor; aeromechanical stability; rotorcraft; helicopter; pitch-lag coupling; ground resonance; pitch-flap coupling; air resonance; aeroelastic couplings; stability; tiltrotor

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Howard, A. K. T. (2008). The Aeromechanical Stability of Soft-Inplane Tiltrotors. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/5861

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Howard, Anna Kathleen Tyler. “The Aeromechanical Stability of Soft-Inplane Tiltrotors.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/5861.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Howard, Anna Kathleen Tyler. “The Aeromechanical Stability of Soft-Inplane Tiltrotors.” 2008. Web. 04 Mar 2021.

Vancouver:

Howard AKT. The Aeromechanical Stability of Soft-Inplane Tiltrotors. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/5861.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Howard AKT. The Aeromechanical Stability of Soft-Inplane Tiltrotors. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/5861

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

4. Kang, Hao. ROTOR BLADE LAG DAMPING USING EMBEDDED CHORDWISE ABSORBERS.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/5881

► The feasibility of helicopter blade lag damping using embedded chordwise absorbers was investigated. The basic feature of this approach is the use of tuned vibration… (more)

▼ The feasibility of helicopter blade lag damping using embedded chordwise absorbers was investigated. The basic feature of this approach is the use of tuned vibration absorbers along the blades. This concept can use a portion of the leading edge weights that are already incorporated into the blade as a part of the mass of the absorbers. It has the potential to replace current blade lag dampers and reduce complexity, aerodynamic drag, and weight. The effectiveness of the embedded absorbers was evaluated by analyzing and testing blade lag damping and rotor system aeromechanical stability. An aeromechanical stability analysis of the rotor system with embedded chordwise absorbers was developed. The rotor blade was modeled as an elastic beam undergoing axial, flapwise, lagwise, and torsional deflections. The fuselage was modeled as a rigid body with roll and pitch rotations about its center of mass. Each embedded absorber was modeled as a mass-spring pair. The rotor-absorber-fuselage system equations of motion were formulated using Hamilton?s Principle and spatially discretized using the finite element method. The modal frequencies and damping of the system were found using complex eigenvalue solutions of the linearized equations. A rigid blade-absorber model was developed to explore the dynamic response of the embedded absorbers, including the static and steady-state dynamic response, and to examine the effect of the embedded absorber on rotor blade aeroelastic stability, including flap-lag flutter, pitch-flap flutter, and pitch divergence. A small-scale model rotor system with embedded absorbers was designed and constructed. A set of experiments measuring blade lag frequency and damping was conducted. The effects of the blade and absorber system parameters, including blade lag stiffness and absorber mass, location, and tuning frequency were examined experimentally. The analytical results were correlated with the experimental data. The theoretical lag frequencies and damping of the blade with embedded absorbers agreed well with the experimental data. The aeromechanical stability analysis of the rotor-fuselage system also showed good agreement with the experimental data. The theoretical and experimental results both showed promising blade lag damping augmentation using embedded chordwise absorbers. The damping augmentation using embedded chordwise absorber varies from 0.3% to 15% critical damping ratio, depending on blade and absorber parameters. The ground resonance stability analysis of the hingeless rotor system and articulated rotor system showed that the blade lag damping augmentation using embedded chordwise absorbers improves the ground resonance stability. A parametric study was performed. The effects of the blade configuration, lag stiffness, pitch setting, and absorber parameters including loss factor, mass, number, and location on the blade were examined. The blade damping using embedded chordwise absorbers for two full-scale rotor systems, a hingeless rotor similar to the BO-105… Advisors/Committee Members: Farhan S Gandhi, Committee Member, George A Lesieutre, Committee Chair/Co-Chair, Kon Well Wang, Committee Member, Edward C Smith, Committee Chair/Co-Chair.

Subjects/Keywords: ROTOR; BLADE; DAMPING; ABSORBER; AEROMECHANICAL STABILITY

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kang, H. (2008). ROTOR BLADE LAG DAMPING USING EMBEDDED CHORDWISE ABSORBERS. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/5881

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kang, Hao. “ROTOR BLADE LAG DAMPING USING EMBEDDED CHORDWISE ABSORBERS.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/5881.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kang, Hao. “ROTOR BLADE LAG DAMPING USING EMBEDDED CHORDWISE ABSORBERS.” 2008. Web. 04 Mar 2021.

Vancouver:

Kang H. ROTOR BLADE LAG DAMPING USING EMBEDDED CHORDWISE ABSORBERS. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/5881.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kang H. ROTOR BLADE LAG DAMPING USING EMBEDDED CHORDWISE ABSORBERS. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/5881

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

5. Keller, Jonathan Allen. Analysis and Control of the Transient Aeroelastic Response of Rotors During Shipboard Engagement and Disengagement Operations.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/5850

► An analysis has been developed to predict the transient aeroelastic response of a helicopter rotor system during shipboard engagement and disengagement operations. The coupled flap-lag-torsion… (more)

▼ An analysis has been developed to predict the transient aeroelastic response of a helicopter rotor system during shipboard engagement and disengagement operations. The coupled flap-lag-torsion equations of motion were developed using Hamilton’s Principle and discretized spatially using the finite element method. Aerodynamics were simulated using nonlinear quasi-steady or time domain nonlinear unsteady models. The ship airwake environment was simulated with simple deterministic airwake distributions, results from experimental measurements or numerical predictions. The transient aeroelastic response of the rotor blades was then time-integrated along a specified rotor speed profile. The control of the rotor response for an analytic model of the H-46 Sea Knight rotor system was investigated with three different passive control techniques. Collective pitch scheduling was only successful in reducing the blade flapping response in a few isolated cases. In the majority of cases, the blade transient response was increased. The use of a discrete flap damper in the very low rotor speed region was also investigated. Only by raising the flap stop setting and using a flap damper four times the strength of the lag damper could the downward flap deflections be reduced. However, because the flap stop setting was raised the upward flap deflections were often increased. The use of extendable/retractable, gated leading-edge spoilers in the low rotor speed region was also investigated. Spoilers covering the outer 15%R of the rotor blade were shown to significantly reduce both the upward and downward flap response without increasing rotor torque. Previous aeroelastic analyses developed at the University of Southampton and at Penn State University were completed with flap-torsion degrees of freedom only. The addition of the lag degree of freedom was shown to significantly influence the blade response. A comparison of the two aerodynamic models showed that the nonlinear quasi-steady aerodynamic model consistently yielded a larger blade response than the time domain nonlinear unsteady model. The transient blade response was also compared using the simple deterministic and numerically predicted ship airwakes for a frigate-like ship shape. The blade response was often much larger for the numerically predicted ship airwakes and was also much more dependent on deck location, wind speed and wind direction. Fluctuating flow components in the range of frequencies measured in previous ship airwake tests were shown to increase the blade response. A separate analysis was developed to investigate the feedback control of gimballed rotor systems using swashplate actuation. The equations of motion for a rigid, three-bladed gimballed rotor system were derived and aerodynamic forces were simulated with a simple, linear attached flow model. A time domain Linear Quadratic Regulator optimal control technique was applied to the equations of motion to minimize the transient rotor response. The maximum transient gimbal tilt angle was reduced… Advisors/Committee Members: George A Lesieutre, Committee Member, Kon Well Wang, Committee Member, Edward C Smith, Committee Chair/Co-Chair, Lyle Norman Long, Committee Member, Farhan S Gandhi, Committee Member.

Subjects/Keywords: helicopters; blade strike; H-46 aircraft; shipboard; aeroelasticity

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Keller, J. A. (2008). Analysis and Control of the Transient Aeroelastic Response of Rotors During Shipboard Engagement and Disengagement Operations. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/5850

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Keller, Jonathan Allen. “Analysis and Control of the Transient Aeroelastic Response of Rotors During Shipboard Engagement and Disengagement Operations.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/5850.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Keller, Jonathan Allen. “Analysis and Control of the Transient Aeroelastic Response of Rotors During Shipboard Engagement and Disengagement Operations.” 2008. Web. 04 Mar 2021.

Vancouver:

Keller JA. Analysis and Control of the Transient Aeroelastic Response of Rotors During Shipboard Engagement and Disengagement Operations. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/5850.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Keller JA. Analysis and Control of the Transient Aeroelastic Response of Rotors During Shipboard Engagement and Disengagement Operations. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/5850

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

6. Bonaventura, Clifford S. A MODULAR APPROACH TO THE DYNAMICS OF COMPLEX ROBOT SYSTEMS .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/5964

► The need for a more general means of modelling and simulating the dynamics of arbitrary robot systems has developed from the increased complexity of modern… (more)

▼ The need for a more general means of modelling and simulating the dynamics of arbitrary robot systems has developed from the increased complexity of modern robot tasks. Today, cooperating robots are used in unstructured environments such as hazardous waste remediation and space-based construction. Multiple robots are now often connected in series and/or in parallel to accomplish their goal. Long-reach flexible manipulators may require bracing to reduce oscillations and increase accuracy. Dynamic simulation of such systems is complicated by the numerous contacts made by the robots as they interact with one another and their surroundings. Most current simulation algorithms are not well suited to the treatment of multiple contacts and require substantial reprogramming when new system tasks or configurations occur. Even algorithms which are inherently suitable for systems with time-varying topologies are limited in the classes of contacts which they allow. This dissertation presents the development and validation of a Modular Robot Dynamic Simulation (MRDS) algorithm. In response to these increasing complexities exhibited by modern, multi-robot systems, this algorithm has been developed to be as general as possible and, as a result, is capable of handling serial, parallel, and hybrid series/parallel topologies for both open-chain and closed-chain systems. The modularity of the approach is achieved by decomposing complex systems into individual physical components such as robots, end effector tools, payloads, obstacles, or other similar objects and devices. This modular nature allows the open chain dynamics of all system models to be performed independently and simultaneously. This is true also for each module’s Forward Kinematics problem and for the computation of several position dependent inertia matrices used to incorporate contact constraints. Consequently, the use of parallel processing is ideal for this algorithm, as one (or more) modules may be treated per processor. This results in increased computational efficiency and real-time capability. Contacts in the system are represented using a general joint/contact model which describes the structure of the contact force and relative motions between a pair of contacting bodies. These contact models are used to connect modules to one another, to fixed boundaries, and to themselves in the case of a module forming or having in its design a single closed loop. With this modelling technique, the MRDS algorithm can be used for contacts that are either holonomic or non-holonomic. In addition, contact modes may be constant or vary with time. The operational space inertia matrix is used to project the dynamics of each module to the operational frame associated with each externally contacted body. A multi-point operational space inertia matrix is also used here for the treatment of modules subject to multiple concurrent contacts. Special “relative forms” of the Jacobian matrix and various inertia matrices are also developed and used for efficiency in treating modules which… Advisors/Committee Members: Kathryn Weed Jablokow, Committee Chair/Co-Chair, H Joseph Sommer Iii, Committee Member, Kon Well Wang, Committee Member, David J Cannon, Committee Member, Keith W Buffinton, Committee Member.

Subjects/Keywords: robotics; forward dynamics; dynamic simulation; constrained motion

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bonaventura, C. S. (2008). A MODULAR APPROACH TO THE DYNAMICS OF COMPLEX ROBOT SYSTEMS . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/5964

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Bonaventura, Clifford S. “A MODULAR APPROACH TO THE DYNAMICS OF COMPLEX ROBOT SYSTEMS .” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/5964.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Bonaventura, Clifford S. “A MODULAR APPROACH TO THE DYNAMICS OF COMPLEX ROBOT SYSTEMS .” 2008. Web. 04 Mar 2021.

Vancouver:

Bonaventura CS. A MODULAR APPROACH TO THE DYNAMICS OF COMPLEX ROBOT SYSTEMS . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/5964.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bonaventura CS. A MODULAR APPROACH TO THE DYNAMICS OF COMPLEX ROBOT SYSTEMS . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/5964

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

7. Kriventsov, Stanislav G. Nonlinear techniques for analysis of DC-DC power converter systems.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/6227

► DC-DC power converters are of great importance in many practical electronic systems, including home appliances, computers, communication equipment, and distributed power systems in ships and… (more)

▼ DC-DC power converters are of great importance in many practical electronic systems, including home appliances, computers, communication equipment, and distributed power systems in ships and airplanes, among other systems. In all of these applications, it is essential that the converter remain within the prescribed operating region, since unstable operation can often lead to catastrophic consequences. Thus, stability analysis of DC-DC converters is an extremely important task. Until now such analysis is usually performed using approximate models such as those obtained through averaging techniques, which have been shown to neglect significant parts of unstable behavior in many real-life systems. There are techniques that describe those phenomena more accurately, but require painstaking analytical derivation for each new system, which is very time-consuming, demands a high level of mathematical proficiency from the engineer, and can lead to errors. In this dissertation a unified nonlinear technique is developed for finding periodic orbits and analyzing their stability in periodically switched DC-DC converter systems. The technique can be applied to systems of arbitrary complexity with possible multiple independently controlled switches and discontinuous topologies. The new approach, based on discrete nonlinear maps, is exact under the assumption of ideal switches and is easily programmable, which allows for quick analysis of a given DC power system under a wide range of input conditions. The exactness of the new method is a definite advantage over existing linear methods and other approximate techniques. The developed method can also be used to analyze bifurcations in DC-DC converter systems. Based on the new approach, a systematic study is performed on loss of stability and bifurcations occurring in basic power converter circuits under current-mode control, including buck, boost, and buck-boost converters. Many other useful results are achieved pertaining to the area of nonlinear DC-DC power system analysis. Advisors/Committee Members: Jeffrey Scott Mayer, Committee Chair/Co-Chair, Charles Lee Croskey, Committee Member, Kwang Yun Lee, Committee Member, Kon Well Wang, Committee Member, Heath F Hofmann, Committee Member.

Subjects/Keywords: DC-DC converters; power electronics; nonlinear phenomena; bifurcations; piecewise-linear systems; Floquet multipliers; monodromy matrix; buck; boost; automated circuit design; state-space; averaging

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kriventsov, S. G. (2008). Nonlinear techniques for analysis of DC-DC power converter systems. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/6227

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kriventsov, Stanislav G. “Nonlinear techniques for analysis of DC-DC power converter systems.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/6227.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kriventsov, Stanislav G. “Nonlinear techniques for analysis of DC-DC power converter systems.” 2008. Web. 04 Mar 2021.

Vancouver:

Kriventsov SG. Nonlinear techniques for analysis of DC-DC power converter systems. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/6227.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kriventsov SG. Nonlinear techniques for analysis of DC-DC power converter systems. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/6227

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

8. Samsi, Rohan. A Probabilistic Framework for Fault Detection in Induction Motors.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7410

► Online monitoring of induction motor health is of increasing interest, as the industrial processes that depend on these motors become more complex and as the… (more)

▼ Online monitoring of induction motor health is of increasing interest, as the industrial processes that depend on these motors become more complex and as the performance to cost ratio of monitoring technology (e.g. sensors, microprocessors) continues to increase. Much effort has been directed towards developing methods that use conventional signal processing and pattern classification techniques. This thesis addresses the main issues of detecting electrical and mechanical faults using the information provided by current and vibration sensors, within a probabilistic framework. The faults studied in this work are stator voltage imbalances (electrical), rotor bar failures (electro-mechanical) and bearing outer race failure (mechanical). These failures are representative of almost all the failures occurring in induction machines. Voltage imbalance has been the longest studied problem. These arise either due to the faulty topology of the electrical system or stator winding faults. Rotor bar faults have accounted for about 10% of failures in induction machines, they are the most difficult type of failures to detect. Bearing failure accounts for 40% of all known failures. There is no direct instrumentation known to detect these kinds of failures. The framework developed provides a common solution methodology for the detection of all these different faults. The methodology utilizes a combination of machine modeling concepts, along with wavelet, and symbolic dynamic analysis to ensure early detection. Additionally the sensor fusion technique developed, presents a probabilistic approach to the problem of bearing faults in induction motors. The method extends the D-Markov process to combine the information from both electrical and mechanical sensors. This provides accurate detection, with a low false alarm rate. The technique has been simulated using the magnetic equivalent circuit method and experimentally validated on 2-hp squirrel cage induction motors. Advisors/Committee Members: Jeffrey Scott Mayer, Committee Chair/Co-Chair, Asok Ray, Committee Chair/Co-Chair, Heath F Hofmann, Committee Member, Kon Well Wang, Committee Member.

Subjects/Keywords: anomaly detection; induction machines; drives; signal processing

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Samsi, R. (2008). A Probabilistic Framework for Fault Detection in Induction Motors. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7410

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Samsi, Rohan. “A Probabilistic Framework for Fault Detection in Induction Motors.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/7410.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Samsi, Rohan. “A Probabilistic Framework for Fault Detection in Induction Motors.” 2008. Web. 04 Mar 2021.

Vancouver:

Samsi R. A Probabilistic Framework for Fault Detection in Induction Motors. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/7410.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Samsi R. A Probabilistic Framework for Fault Detection in Induction Motors. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7410

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

9. Martin, Jay Dean. A Methodology for Evaluating System-Level Uncertainty in the Conceptual Design of Complex Multidisciplinary Systems.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/6549

► Conceptual design is the early stage of system design, when little is precisely known about the physical description of a new system. One of the… (more)

▼ Conceptual design is the early stage of system design, when little is precisely known about the physical description of a new system. One of the goals in conceptual design is to aggregate all current corporate knowledge about the new design and exhaustively search the feasible design space to find potential designs that best meet the design's requirements and satisfies its constraints. In the conceptual design stage, simplified models are often created in preference to more complex models to permit the rapid assessment of many designs that cover the entire feasible design space. Uncertainty in the assessment of a potential design may result from uncertainty in the inputs to the design, such as sizes, weights, efficiencies, or costs. The use of simplified models may also introduce additional uncertainty, termed model uncertainty, due to the reduction in the number of parameters used to describe the system or due to incorrect relationships between parameters. A metamodel is a "model of a model" and can be used as a computationally efficient approximation to a computer model such as a finite element analysis. Kriging models are a type of metamodel that can interpolate their observations and provide a probability distribution of the output that quantifies the model uncertainty. Kriging models are created as simplified models from observations of detailed subsystem models. A Monte Carlo simulation (MCS) based methodology is developed to permit the specification of arbitrary probability distributions of the inputs to the system design using a hierarchy of kriging models. Through the use of kriging models, the model uncertainty introduced can also be quantified along with the input uncertainties' impact on the system performance measurements. This methodology is demonstrated on a satellite design problem composed of three subsystems. These results are compared to those found using original computer models in the MCS system uncertainty assessment. This methodology enables the computationally efficient use of MCS with simple random sampling to estimate the resulting uncertainty of the system's performance parameters given the probability distribution of the system inputs and the uncertainty introduced by using approximations to the original deterministic computer models. Advisors/Committee Members: Timothy William Simpson, Committee Chair/Co-Chair, Kon Well Wang, Committee Member, Russell Richard Barton, Committee Member, Mark Thomas Traband, Committee Member, Runze Li, Committee Member.

Subjects/Keywords: conceptual design; uncertainty assessment; sensitivity analysis; kriging models

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Martin, J. D. (2008). A Methodology for Evaluating System-Level Uncertainty in the Conceptual Design of Complex Multidisciplinary Systems. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/6549

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Martin, Jay Dean. “A Methodology for Evaluating System-Level Uncertainty in the Conceptual Design of Complex Multidisciplinary Systems.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/6549.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Martin, Jay Dean. “A Methodology for Evaluating System-Level Uncertainty in the Conceptual Design of Complex Multidisciplinary Systems.” 2008. Web. 04 Mar 2021.

Vancouver:

Martin JD. A Methodology for Evaluating System-Level Uncertainty in the Conceptual Design of Complex Multidisciplinary Systems. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/6549.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Martin JD. A Methodology for Evaluating System-Level Uncertainty in the Conceptual Design of Complex Multidisciplinary Systems. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/6549

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

10. Kamali, Kaivan. MULTIPARTY PROACTIVE COMMUNICATION: A PERSPECTIVE FOR EVOLVING SHARED MENTAL MODELS.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7673

► Psychologists who have studied human team performance point out that helping behavior (e.g. proactive sharing of relevant information) in effective teams is achieved via an… (more)

▼ Psychologists who have studied human team performance point out that helping behavior (e.g. proactive sharing of relevant information) in effective teams is achieved via an overlapping “shared mental model” that is developed and maintained by members of the team. In this research, we take the perspective that multiparty proactive communication is critical for establishing and maintaining such a shared mental model among teammates, which is the basis for agents to offer proactive help and to achieve coherent teamwork. Agent communication languages like KQML and FIPA, however, mostly focus on two-party communications and do not provide well defined multiparty performatives. In this research, we provide formal semantics for multiparty proactive performatives within a team setting for agents to share relevant information. The ultimate goal of this research is to develop agent theories and technologies that can assist human decision makers in overhearing multiparty communications, so that they can maintain their evolving shared mental models without being overwhelmed. With this goal in mind, we make the following contributions in addressing the challenges of information sharing among members of a team: First, we propose formal semantics for a set of multiparty proactive performatives in the context of a team. Such performatives can be used in designing agent teams that involve multiparty proactive communication. Second, we formally prove how multiparty proactive communication update the shared mental models among team members, allowing them to proactively offer relevant information to their teammates. Third, we introduce communication policies for multiparty proactive performatives. Finally, we conduct experiments to evaluate the cost and benefits of multiparty communication in a simulated command and control decision making environment for an urban combat application domain. Advisors/Committee Members: John Yen, Committee Chair/Co-Chair, C Lee Giles, Committee Member, Jia Li, Committee Member, Kon Well Wang, Committee Member, Raj Acharya, Committee Member.

Subjects/Keywords: Distributed AI; Multiagent systems; Agent communication languages (ACL)

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kamali, K. (2008). MULTIPARTY PROACTIVE COMMUNICATION: A PERSPECTIVE FOR EVOLVING SHARED MENTAL MODELS. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7673

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kamali, Kaivan. “MULTIPARTY PROACTIVE COMMUNICATION: A PERSPECTIVE FOR EVOLVING SHARED MENTAL MODELS.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/7673.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kamali, Kaivan. “MULTIPARTY PROACTIVE COMMUNICATION: A PERSPECTIVE FOR EVOLVING SHARED MENTAL MODELS.” 2008. Web. 04 Mar 2021.

Vancouver:

Kamali K. MULTIPARTY PROACTIVE COMMUNICATION: A PERSPECTIVE FOR EVOLVING SHARED MENTAL MODELS. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/7673.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kamali K. MULTIPARTY PROACTIVE COMMUNICATION: A PERSPECTIVE FOR EVOLVING SHARED MENTAL MODELS. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7673

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

11. Qin, Wubi. Feedback Performance Control for Self-Managing Computer Systems: an LPV Control Theoretic Approach .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7652

► High-performance server systems have been widely used in today's commercial and scientific server environments, for example, Web and Email applications, online trading and multimedia services,… (more)

▼ High-performance server systems have been widely used in today's commercial and scientific server environments, for example, Web and Email applications, online trading and multimedia services, and many more. This research investigates the autonomic performance management of computer server systems in the context of Internet hosting centers. Two scenarios of the performance mangagement problem are studied: admission control and resource allocation. This research contributes to the problem in three major aspects: modeling of Internet services via new approaches, more realistic and advanced control designs, and intensive performance evaulations of various design solutions. Modeling wise, it is learned that the linear methods may not be adequate for Internet services modeling when there are large variations in load conditions. Consequently, more sophisticated nonlinear system modeling is needed to improve system performance and robustness with respect to large variations of load conditions. A linear uncertain model and a Linear-Parameter-Varying (LPV) model of hosting center server systems are derived based on theoretical analysis of transient queueing dynamics, as well as LPV system identification, where workload characterizing parameters are utilized as scheduling variables. Exisiting feedback control based performance management for Internet server systems relies on worst-case estimates of load and resource availability thus provisions resources to meet peak demands. Since the worst-case resource demand is likely to be significantly higher than its normal usage, these methods could be economically unfavorable. This work focuses on the development of an LPV control design for the performance management of server where time-varying effects of the system are explicitly considered by utilizing workload arrival and service parameters as scheduling variables. Further, it is widely noticed that workload parameters of Internet services are more or less unpredictable. This makes deterministic modeling and control design approaches either too conservative or unable to meet performance service level agreements (SLA). Probabilistic modeling and control design methods are proposed to balance between the risk of missing performance SLA and the resource efficiency. Request level approach to provide response time guarantee based on detailed analysis of requests response time components is studied. A request level scheduling algorithm is proposed that can be used with workload characterization and modeling techniques. Preliminary results in a response time guarantee problem show impressive request level performance over a wide range of sampling intervals. Intensive simulations are conducted using real Web server workloads. Performances of the proposed LPV based modeling and control design approaches are benchmarked using queueing theory based provisioning results and existing linear control modeling & designs. It is shown that the proposed method outperforms linear control and conventional queueing-theory based designs. These… Advisors/Committee Members: Dr Qian Wang, Committee Chair/Co-Chair, Asok Ray, Committee Member, Dr Kon Well Wang, Committee Member, Anand Sivasubramaniam, Committee Member.

Subjects/Keywords: linear parameter varying systems (lpv); internet services; feedback control; performance management; quality of service (qos); request level scheduling; web server

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Qin, W. (2008). Feedback Performance Control for Self-Managing Computer Systems: an LPV Control Theoretic Approach . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7652

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Qin, Wubi. “Feedback Performance Control for Self-Managing Computer Systems: an LPV Control Theoretic Approach .” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/7652.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Qin, Wubi. “Feedback Performance Control for Self-Managing Computer Systems: an LPV Control Theoretic Approach .” 2008. Web. 04 Mar 2021.

Vancouver:

Qin W. Feedback Performance Control for Self-Managing Computer Systems: an LPV Control Theoretic Approach . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/7652.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Qin W. Feedback Performance Control for Self-Managing Computer Systems: an LPV Control Theoretic Approach . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7652

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

12. Hailu, Haftay. DIMENSIONAL TRANFORMATION: A NOVEL METHOD FOR GAIN-SCHEDULING AND ROBUST CONTROL.

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7016

► This thesis focuses on developing a technique of dimensional transformation to solve advanced controller design problems, specifically gain-scheduling and robust control methods. The developed technique… (more)

▼ This thesis focuses on developing a technique of dimensional transformation to solve advanced controller design problems, specifically gain-scheduling and robust control methods. The developed technique reformulates the system representation in preferential dimensionless form that is more tenable for gain scheduling and robust control designs. The current work shows that the dimensionless formulation gives advantage in terms of reducing complexity and conservativeness of the control synthesis as compared to the dimensional form. The complexity of a gain scheduling control design increases exponentially with the number of scheduling parameters. This thesis presents a method called dimensional transformation that reduces the number of scheduling parameters by reformulating the dynamic representation in dimensionless form. The choice of dimensionless description is usually preferred because any transformation to dimensionless representation is guaranteed to reduce variable dependence: the number of dimensionless parameters is always less than or equal to that of the classical representation (a result of the classic Pi-theorem). However, dimensional transformations are not unique. Some transformations – while reducing the total number of system parameters, scheduled or unscheduled – may have a negative effect on a gain-scheduling control algorithm because they may inadvertently increase the number of scheduling parameters. This work explores in detail conditions necessary such that dimensional transformation are guaranteed to present the minimum number of gain scheduling parameters for a control system design. The same principle of dimensional transformation is explored as a method to reduce the size of parametric uncertainty block in robust controller synthesis. This simplification is performed using the dimensional transformation by appropriate matrices followed by LFT reformulation in the dimensionless domain. This reduces the conservativeness of the robust control synthesis. For example, in the mu-synthesis framework, if the uncertainty block size is greater than three, then only the upper bound can be computed, and this upper bound can be arbitrarily larger than the actual structured singular value resulting in a more conservative controller synthesis. Through the method of dimensional transformation, the size of a given uncertainty block can be reduced by up to three or more dimensions. Depending on the problem, this might allow for current techniques of robust control synthesis to be extended into significant new problems. This thesis also discusses methods for a robust simultaneous control technique for systems whose system parameters are inherently coupled. The current work shows the potential of the proposed method for designing a unified robust controller that can be implemented through parametric adaptation. The goal is to obtain a robust, adaptive and modular controller for a group of systems. When considering collective group of systems, passenger vehicles for example, coupling is present due to… Advisors/Committee Members: Sean Brennan, Committee Chair/Co-Chair, Christopher Rahn, Committee Member, Mario Sznaier, Committee Member, Barbara E Kulakowski, Committee Member, Kon Well Wang, Committee Member.

Subjects/Keywords: robust control; gain-scheduling; dimensional transformation; dimensional analysis

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hailu, H. (2008). DIMENSIONAL TRANFORMATION: A NOVEL METHOD FOR GAIN-SCHEDULING AND ROBUST CONTROL. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7016

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hailu, Haftay. “DIMENSIONAL TRANFORMATION: A NOVEL METHOD FOR GAIN-SCHEDULING AND ROBUST CONTROL.” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/7016.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hailu, Haftay. “DIMENSIONAL TRANFORMATION: A NOVEL METHOD FOR GAIN-SCHEDULING AND ROBUST CONTROL.” 2008. Web. 04 Mar 2021.

Vancouver:

Hailu H. DIMENSIONAL TRANFORMATION: A NOVEL METHOD FOR GAIN-SCHEDULING AND ROBUST CONTROL. [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/7016.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hailu H. DIMENSIONAL TRANFORMATION: A NOVEL METHOD FOR GAIN-SCHEDULING AND ROBUST CONTROL. [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7016

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

13. Shan, Ying. Flexible Matrix Composites: Dynamic Characterization, Modeling, and Potential for Driveshaft Applications .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7258

► Flexible matrix composites (FMCs) utilize the high elongation capability of elastomers such as polyurethane to withstand large strains in the direction transverse to the fiber… (more)

▼ Flexible matrix composites (FMCs) utilize the high elongation capability of elastomers such as polyurethane to withstand large strains in the direction transverse to the fiber reinforcement while retaining strength and stiffness in the longitudinal direction. FMCs are highly anisotropic and can therefore be tailored to achieve distinctive mechanical characteristics that are difficult to obtain using conventional rigid matrix composites. In the current study, the potential of using an FMC to construct a flexurally-soft, torsionally-stiff driveshaft is examined. The FMC selected for the current investigation is a carbon fiber/polyurethane matrix material system. Both quasi-static and dynamic tests have been performed to characterize the properties of the FMC material. By modeling viscoelastic FMC lamina properties with a fractional derivative approach, a novel damping model that accounts for the frequency and temperature dependence of the FMC material is developed. This is the first time fractional derivative model has been applied to a fiber composite. Good agreement between the damping model and experimental data for angle-ply tubes was obtained. Based on the validated damping model, a self-heating model to predict the temperature increase caused by internal damping of a FMC shaft under misaligned rotation is also proposed. A laboratory-scale, misaligned FMC shaft rotation test stand was built to validate the proposed model. Good agreement is shown between the self-heating model predictions and experiment results. This model can be valuable in the selection of constituent materials for FMCs and also in the design of FMC shafts. Preliminary fatigue test results show that FMC materials have potentially good fatigue performance in shaft applications. Advisors/Committee Members: Charles E Bakis, Committee Chair/Co-Chair, Francesco Costanzo, Committee Member, Clifford Jesse Lissenden Iii, Committee Member, Edward C Smith, Committee Member, Kon Well Wang, Committee Member.

Subjects/Keywords: self heating; damping; driveshaft; composites; flexible matrix; thermomechanical

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Shan, Y. (2008). Flexible Matrix Composites: Dynamic Characterization, Modeling, and Potential for Driveshaft Applications . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7258

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Shan, Ying. “Flexible Matrix Composites: Dynamic Characterization, Modeling, and Potential for Driveshaft Applications .” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/7258.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Shan, Ying. “Flexible Matrix Composites: Dynamic Characterization, Modeling, and Potential for Driveshaft Applications .” 2008. Web. 04 Mar 2021.

Vancouver:

Shan Y. Flexible Matrix Composites: Dynamic Characterization, Modeling, and Potential for Driveshaft Applications . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/7258.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Shan Y. Flexible Matrix Composites: Dynamic Characterization, Modeling, and Potential for Driveshaft Applications . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7258

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

14. Saribay, Zihni Burcay. ANALYTICAL INVESTIGATION OF THE PERICYCLIC VARIABLE-SPEED TRANSMISSION SYSTEM FOR HELICOPTER MAIN-GEARBOX .

Degree: 2009, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/10291

► In the recent years, there has been significant interest in the new developments and improvements of the rotorcraft transmission systems. The main goal of the… (more)

▼ In the recent years, there has been significant interest in the new developments and improvements of the rotorcraft transmission systems. The main goal of the rotorcraft transmission research is the reduction of overall gear train weight while maintaining the efficiency and reliability. The Pericyclic Variable-Speed Transmission (PVT) System is one of the potential candidates of the future rotorcraft drive trains to achieve these goals. Hence, this thesis explores the feasibility of the Pericyclic Variable Speed Transmission (PVT) for rotorcraft transmissions. The contributions of this research are grouped in two main categories. These two categories are in the component level and in the system level. These contributions are originated from the analysis of the Pericyclic Variable Speed (PVT) System. In the component level, a new concept of face-gear meshing is presented first time in the gear research field. The meshing of a face-gear with another face-gear is presented at high shaft angles as an alternative to bevel gears. The conjugacy of this new face-gear meshing concept is formulated and demonstrated. The geometry, unloaded mesh kinematics and loaded mesh kinematics of the conjugate meshing face-gear pair is analyzed. The physics behind the meshing face-gear teeth contact is revealed using theory of gearing, differentiable geometry and elastohydrodynamic lubrication theory. The existence of the lubricant film formation between the meshing teeth is demonstrated. The behavior of the sliding friction coefficient is analytically simulated through the meshing cycle. In the system level contributions, the Pericyclic Variable Speed (PVT) Transmission is presented as a new unique innovative gear train mechanism. The speed change capability is analyzed for rotorcraft demands. The power flow behavior is explored for its use in variable speed transmission systems. The established component level contributions are evaluated with the PVT at the system level. The efficiency and load carrying capacity of the PVT face-gears are analyzed at the helicopter torque levels. The dynamic motion of the nutating gear mechanisms is studied to capture the load carrying capacity of the PVT support bearings. A design analysis of the PVT system with 24:1 reduction ratio at 764HP power level is conducted to replace 3 reduction stages of the existing K-MAX intermeshing rotor transmission system. The design and analysis tools established in this research are applied in the design study. The achieved design is compared to the existing K-MAX transmission. Approximately 50% weight reduction and 70% volume reduction are accomplished with the PVT system with less than 1% lower efficiency than existing K-MAX drive train gears. Advisors/Committee Members: Edward C Smith, Dissertation Advisor/Co-Advisor, Edward Smith, Committee Chair/Co-Chair, Surendra B Rao, Committee Chair/Co-Chair, Robert Charles Bill, Committee Member, Kon Well Wang, Committee Member, Joseph Francis Horn, Committee Member, Liming Chang, Committee Member.

Subjects/Keywords: Helicopter Transmission; face-gear; pericyclic variable-speed transmission; elastohydrodynamic lubrication

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Saribay, Z. B. (2009). ANALYTICAL INVESTIGATION OF THE PERICYCLIC VARIABLE-SPEED TRANSMISSION SYSTEM FOR HELICOPTER MAIN-GEARBOX . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/10291

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Saribay, Zihni Burcay. “ANALYTICAL INVESTIGATION OF THE PERICYCLIC VARIABLE-SPEED TRANSMISSION SYSTEM FOR HELICOPTER MAIN-GEARBOX .” 2009. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/10291.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Saribay, Zihni Burcay. “ANALYTICAL INVESTIGATION OF THE PERICYCLIC VARIABLE-SPEED TRANSMISSION SYSTEM FOR HELICOPTER MAIN-GEARBOX .” 2009. Web. 04 Mar 2021.

Vancouver:

Saribay ZB. ANALYTICAL INVESTIGATION OF THE PERICYCLIC VARIABLE-SPEED TRANSMISSION SYSTEM FOR HELICOPTER MAIN-GEARBOX . [Internet] [Thesis]. Penn State University; 2009. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/10291.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Saribay ZB. ANALYTICAL INVESTIGATION OF THE PERICYCLIC VARIABLE-SPEED TRANSMISSION SYSTEM FOR HELICOPTER MAIN-GEARBOX . [Thesis]. Penn State University; 2009. Available from: https://submit-etda.libraries.psu.edu/catalog/10291

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

15. Palacios, Jose Luis. Design, Fabrication, and Testing of an Ultrasonic De-Icing System for Helicopter Rotor Blades .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/8199

► A low-power, non-thermal ultrasonic de-icing system is introduced as a possible substitute for current electro-thermal systems. The system generates delaminating ultrasonic transverse shear stresses at… (more)

▼ A low-power, non-thermal ultrasonic de-icing system is introduced as a possible substitute for current electro-thermal systems. The system generates delaminating ultrasonic transverse shear stresses at the interface of accreted ice. A PZT-4 disk driven at 28.5 KHz (radial resonance of the disk) instantaneously de-bonds 2 mm thick freezer ice layers. The ice layers are accreted to a 0.7 mm thick, 30.4 cm x 30.4 cm steel plate at an environment temperature of -200 C. A power input of 50 Watts is applied to the actuator (50 V, 19.6 KV/m), which translates to a de-icing power of 0.07 W/cm2. A finite element model of the actuator bonded to the isotropic plate is used to guide the design of the system, and predicts the transverse shear stresses at the ice interface. Wind tunnel icing tests were conducted to demonstrate the potential use of the proposed system under impact icing conditions. Both glaze ice and rime ice were generated on steel and composite plates by changing the cloud conditions of the wind tunnel. Continuous ultrasonic vibration prevented impact ice formation around the actuator location at an input power not exceeding 0.18 W/cm2 (1.2 W/in2). As ice thickness reached a critical thickness of approximately 1.2 mm, shedding occurred on those locations where ultrasonic transverse shear stresses exceeded the shear adhesion strength of the ice. Finite element transverse shear stress predictions correlate with observed experimental impact ice de-bonding behavior. To increase the traveling distance of propagating ultrasonic waves, ultrasonic shear horizontal wave modes are studied. Wave modes providing large modal interface transverse shear stress concentration coefficients (ISCC) between the host structure (0.7 mm thick steel plate) and accreted ice (2.5 mm thick ice layer) are identified and investigated for a potential increase in the wave propagation distance. Ultrasonic actuators able to trigger these optimum wave modes are designed and fabricated. Despite exciting wave modes with high ISCC values, instantaneous ice de-bonding is not observed at input powers under 100 Watts. The two triggered ultrasonic wave modes of the structure occur at high excitation frequencies, 202 KHz and 500 KHz respectively. At these frequencies, the ultrasonic actuators do not provide large enough transverse shear stresses to exceed the shear adhesion strength of the ice layer. Neither the actuator exciting the SH1 mode (202 KHz), nor the actuator triggering the SH2 mode (500 KHz) instantaneously de-bonds ice layers with an input power under 100 Watts. Advisors/Committee Members: Edward A Smith, Committee Chair/Co-Chair, Joseph Rose, Committee Chair/Co-Chair, Farhan Gandhi, Committee Member, Cengiz Camci, Committee Member, Bernhard R Tittmann, Committee Member, Kon Well Wang, Committee Member.

Subjects/Keywords: dispersion curves; icing rotor blades; ice protection; anti-icing; de-icing; ultrasound; wave structure; high power ultrasound

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Palacios, J. L. (2008). Design, Fabrication, and Testing of an Ultrasonic De-Icing System for Helicopter Rotor Blades . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/8199

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Palacios, Jose Luis. “Design, Fabrication, and Testing of an Ultrasonic De-Icing System for Helicopter Rotor Blades .” 2008. Thesis, Penn State University. Accessed March 04, 2021. https://submit-etda.libraries.psu.edu/catalog/8199.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Palacios, Jose Luis. “Design, Fabrication, and Testing of an Ultrasonic De-Icing System for Helicopter Rotor Blades .” 2008. Web. 04 Mar 2021.

Vancouver:

Palacios JL. Design, Fabrication, and Testing of an Ultrasonic De-Icing System for Helicopter Rotor Blades . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 04]. Available from: https://submit-etda.libraries.psu.edu/catalog/8199.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Palacios JL. Design, Fabrication, and Testing of an Ultrasonic De-Icing System for Helicopter Rotor Blades . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/8199

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Open Access Theses and Dissertations