This paper is concerned with the problem of motion generation via cyclic variations in selected degrees of freedom (usually referred to as shape variables) in mechanical systems subject to...
Key Words: Nonholonomic Motion Planning � Variable Geometry Truss � Parallel Manipulators (2008)
P. S. Krishnaprasad, D. P. Tsakiris
Abstract: The nonholonomic motion planning problem is considered for a novel class of modular mobile manipulators, where each module is implemented as a planar parallel manipulator with idler wheels....
ACTIVE POINTING CONTROL FOR SHORT RANGE FREE-SPACE OPTICAL COMMUNICATION ∗ (2008)
Arash Komaee, P. S. Krishnaprasad, Prakash Narayan
Abstract. Maintaining optical alignment between stations of a free-space optical link requires an active pointing mechanism to persistently aim an optical beam toward the receiving station with an...
Robot Phonotaxis with Dynamic Sound-source Localization (2008)
Sean B. Andersson, Amir A. H, Vinay Shah, P. S. Krishnaprasad
Abstract — We address two key goals pertaining to autonomous mobile robots: one, to develop fast accurate sensory capabilities — at present, the localization of sound sources — and second, the...
Tracking and Stabilization for Control Systems on Matrix Lie Groups (2007)
Herbert Struemper, P. S. Krishnaprasad
A wide range of dynamical systems from fields as diverse as mechanics, electrical networks and molecular chemistry can be modeled by invariant systems on matrix Lie groups. This paper introduces...
Tracking and Stabilization for Control Systems on Matrix Lie Groups (2007)
Herbert Struemper, P.S. Krishnaprasad
A wide range of dynamical systems from fields as diverse as mechanics, electrical networks and molecular chemistry can be modeled by invariant systems on matrix Lie groups. This paper introduces...
Control Problems Of Hydrodynamic Type (2007)
Krishnaprasad Vikram, P. S. Krishnaprasad
: It has been known for some time that the classical work of Kirchhoff, Love, and Birkhoff on rigid bodies in incompressible, irrotational flows provides effective models for treating control...
Echolocating Bats Use a Nearly Time-Optimal Strategy to Intercept Prey (2006)
Kaushik Ghose, Timothy K. Horiuchi, P. S. Krishnaprasad, Cynthia F. Moss
Acquisition of food in many animal species depends on the pursuit and capture of moving prey. Among modern humans, the pursuit and interception of moving targets plays a central role in a variety of...
A Novel Non-Orthogonal Joint Diagonalization Cost Function for ICA (2005)
Afsari, Bijan, Krishnaprasad, P.S.
We present a new scale-invariant cost function for non-orthogonal joint-diagonalization of a set of symmetric matrices with application to Independent Component Analysis (ICA). We derive two gradient...
Quotient Signal Estimation (2005)
D. Napoletani, C. A. Berenstein, P. S. Krishnaprasad, D. C: Struppa
In this paper we propose a method for blind signal decomposition that does not require the independence or stationarity of the sources. We define suitable quotients of linear combinations of the...
The Hannay-Berry Phase of the Vibrating Ring Gyroscop (2004)
Andersson, Sean B., Krishnaprasad, P.S.
In an analysis published in 1890 G.H. Bryan investigated the retrograde precession of the nodal points in a vibrating, rotating shell and wrote down a formula relating the rate of precession to the...
A Particle Filtering Approach to Change Detection for Nonlinear Systems (2004)
Babak Azimi-Sadjadi, P. S. Krishnaprasad
We present a change detection method for nonlinear stochastic systems based on particle filtering. We assume that the parameters of the system before and after change are known. The statistic for...
Experimental study of curvature-based control laws for obstacle avoidance (2004)
Fumin Zhang, Derek Luebke, P. S. Krishnaprasad
Abstract — A novel curvature-based steering control law is introduced to produce the obstacle avoidance behavior for unicycle type robots traveling (flying) at constant speed. Different methods of...
Some gradient based joint diagonalization methods for (2004)
Bijan Afsari, P. S. Krishnaprasad
Abstract. We present a set of gradient based orthogonal and nonorthogonal matrix joint diagonalization algorithms. Our approach is to use the geometry of matrix Lie groups to develop continuous-time...
A Particle Filtering Approach to Change Detection for Nonlinear Systems (2004)
P. S. Krishnaprasad, Babak Azimi-Sadjadi
We present a change detection method for nonlinear stochastic systems based on particle filtering. We assume that the parameters of the system before and after change are known. The statistic for...
A Particle Filtering Approach to Change Detection for Nonlinear Systems (2004)
Babak Azimi-Sadjadi, P. S. Krishnaprasad
We present a change detection method for nonlinear stochastic systems based on particle filtering. We assume that the parameters of the system before and after change are known. The statistic for...
On the Structural Complexity of the Motion Description Language MDLe (2003)
Hristu-Varsakelis, Dimitrios, Egerstedt, Magnus, Krishnaprasad, P. S.
As modern control theory attempts to elucidate the complexity of systems that combine differential equations and event-driven logic, it must overcome challenges having to do with limited expressive...
Control of Hysteresis in Smart Actuators with Application to Micro-Positioning (2003)
Tan, Xiaobo, Baras, John S., Krishnaprasad, P. S.
Hysteresis in smart material actuators makes the effective use of these actuators quite challenging. The Preisach operator has been widely used to model smart material hysteresis. Motivated by...
Control of Small Formations Using Shape Coordinates (2003)
Zhang, Fumin, Goldgeier, Michael, Krishnaprasad, P.S.
Formations that contain a small number of robots are modeled as controlled Lagrangian systems on Jacobi shape space. This allows a block-structured control of position, orientation and shape of the...
On the Structural Complexity of the Motion Description Language MDLe (2003)
Χρήστου-Βαρσακέλης, Δημήτριος, Hristu-Varsakelis, Dimitrios, Egerstedt, M., Krishnaprasad, P.S.
Andersson, Sean B., Krishnaprasad, P.S.
In this work we apply the moving systems approach developed by Marsden, Montgomery, and Ratiu to a free-floating, equal-sided, spring-jointed, four-bar mechanism that is being slowly rotated about...
Coordinated Orbit Transfer for Satellite Clusters (2002)
Zhang, Fumin, Krishnaprasad, P.S.
We propose a control law which allows a satellite formation to achieveorbit transfer. During the transfer, the formationcan be either maintained or modified to a desired one.Based on the orbit...
A Simple Control Law for UAV Formation Flying (2002)
Justh, Eric W., Krishnaprasad, P.S.
This paper presents a Lie group setting for the problem of control of formations, as a natural outcome of the analysis of a planar two-vehicle formation control law. The vehicle trajectories are...
A Dynamic Model for Magnetostrictive Hysteresis (2002)
Tan, Xiaobo, Baras, John S., Krishnaprasad, P. S.
The rate-dependent hysteresis present in thin magnetostrictive actuators can be captured by a dynamic model, consisting of a Preisach operator coupled to an ordinary differential equation in an...
Quotient Signal Decomposition and Order Estimation (2002)
Napoletani, D., Berenstein, Carlos A., Krishnaprasad, P.S.
In this paper we propose a method for blind signal decomposition that does not require the independence or stationarity of the sources. This method, that we consider a simple instance of non-linear...
Degenerate Gradient Flows: A Comparison Study of Convergence Rate Estimates (2002)
Andersson, Sean B., Krishnaprasad, P.S.
Degenerate gradient flows arise in the context of adaptive control of linear systems when the usual gradient algorithm is used for the parameter update law. It is well known that in general parameter...
Analysis of a high-resolution optical wave-front control system (2002)
Justh, Eric W., Krishnaprasad, P.S.
We consider the formulation and analysis of a problem of automaticcontrol: correcting for the distortion induced in an optical wave frontdue to propagation through a turbulent atmosphere. It has...
Formation Dynamics under a Class of Control Laws (2002)
Zhang, Fumin, Krishnaprasad, P.S.
A system of two earth satellites is analyzed as a controlled mechanical system. The orbit of an earth satellite can be represented by a point inthe vector space of ordered pairs of angular momentum...
D. Napoletani, D. Napoletani, C. A. Berenstein, C. A. Berenstein, P. S. Krishnaprasad, P. S. Krishnaprasad
ISR develops, applies and teaches advanced methodologies of design and analysis to solve complex, hierarchical,
Approximate Nonlinear Filtering and Its Applications for GPS (2001)
Azimi-Sadjadi, Babak, Krishnaprasad, P.S.
In this paper we address the problem of nonlinear filtering in the presence of integer uncertainty. In the simulation results we show that Particle Filtering is capable of resolving integer ambiguity...
Control of Hysteresis: Theory and Experimental Results (2001)
Tan, Xiaobo, Venkataraman, Ram, Krishnaprasad, P.S.
Hysteresis in smart materials hinders the wider applicability ofsuch materials in actuators. In this paper, a systematic approachfor coping with hysteresis is presented. The method is...
Tan, Xiaobo, Baras, John S., Krishnaprasad, P.S.
Computational micromagnetics in three dimensions is of increasing interest with the development of magnetostrictivesensors and actuators. In solving the Landau-Lifshitz-Gilbert (LLG) equation, the...
The Berry-Hannay Phase of the Equal-Sided Spring-Jointed Four-Bar Mechanism (2001)
Andersson, Sean B., Krishnaprasad, P.S.
In this work we apply the moving systems approach developed by Marsden, Montgomery, and Ratiu to a free-floating, equal-sided, spring-jointed, four-bar mechanism that is being slowly rotated about...
Adaptive Wavefront Control using a Nonlinear Zernike Filter (2001)
Justh, Eric W., Vorontsov, Mikhail A., Carhart, Gary W., Beresnev, Leonid A., Krishnaprasad, P.S.
A conventional Zernike filter measures wavefront phase by superimposing the aberrated input beam with a phase-shifted version of its zero-orderspectral component. The Fourier-domain phase-shifting is...
Nonlinear Analysis of a High-Resolution Optical Wave-Front Control System (2001)
Justh, Eric W., Krishnaprasad, P.S., Vorontsov, M.A.
A class of feedback systems for high-resolution optical wave-front control(or adaptive optic wave-front distortion suppression) is modeled andanalyzed. Under certain conditions, the nonlinear...
Cayley Transforms in Micromagnetics (2001)
Krishnaprasad, P. S., Tan, Xiaobo
Methods of numerical integration of ordinary differential equations exploiting the Cayley transform arise in a variety of contexts, ranging from the classical mid-point rule to symplectic and...
Oscillations, SE(2)-snakes and motion control: a study of the Roller Racer (2001)
P. S. Krishnaprasad, Dimitris P. Tsakiris
This report is concerned with the problem of motion generation via cyclic variations in selected degrees of freedom (usually referred to as shape variables) in mechanical systems subject to...
Oscillations, SE(2)-snakes and motion control: a study of the Roller Racer (2001)
P. S. Krishnaprasad, Dimitris P. Tsakiris
Abstract. This paper is concerned with the problem of motion generation via cyclic variations in selected degrees of freedom (usually referred to as shape variables) in mechanical systems subject to...
Approximate Nonlinear Filtering and its Application in Navigation (2001)
Azimi-Sadjadi And Krishnaprasad, B. Azimi-sadjadi, P. S. Krishnaprasad
In this paper we introduce for the first time particle filtering for an exponential family of densities. We prove that under certain conditions the approximated conditional density converges to the...
Computing Balanced Realizations for Nonlinear Systems (2000)
Newman, Andrew J., Krishnaprasad, P.S.
This paper addresses the problem of computability pertaining to the Scherpen(1994) theory and procedure for balancing of nonlinear systems. In contrastto Moore's (1981) balancing method for linear...
Computational Micromagnetics for Magnetostrictive Actuators (2000)
Tan, X., Baras, John S., Krishnaprasad, P.S.
Computational micromagnetics plays an important role in design and control of magnetostrictive actuators. A systematic approach to calculate magnetic dynamics and magnetostriction is presented. A...
Tan, X., Baras, John S., Krishnaprasad, P.S.
Computational micromagnetics in three dimensions is of increasing interest with the development of magnetostrictive sensors andactuators. In solving the Landau-Lifshitz-Gilbert (LLG) equation, the...
The MDLe Engine -- A Software Tool for Hybrid Motion Control (2000)
Hristu, Dimitrios, Krishnaprasad, P. S., Andersson, Sean B., Zhang, F., Sodre, P., D'Anna, L.
One of the important but often overlooked practical challenges in motion control for robotics and other autonomous machines has to do with the implementation of theoretical tools into software that...
Computing Balanced Realizations for Nonlinear Systems (2000)
Andrew J. Newman, P. S. Krishnaprasad
In 1993, Scherpen generalized the balanced truncation method to the nonlinear setting. However, the Scherpen procedure is not easily computable and has not yet been applied in practice. We offer...
Approximate Nonlinear Filtering and Its Applications for GPS (2000)
B. Azimi-sadjadi, P. S. Krishnaprasad
Abstract In this paper we address the problem of nonlinear filtering in the presence of integer uncertainty. In the simulation results we show that Particle Filtering is capable of resolving integer...
Analysis of a complex activator-inhibitor equation (1999)
Justh, Eric W., Krishnaprasad, P.S.
Basic properties of solutions and a Lyapunov functionalare presented for a complex activator-inhibitor equation witha cubic nonlinearity.Potential applications include control of coupled-oscillator...
Modeling and Optimization for Epitaxial Growth: Transport and Growth Studies (1999)
Newman, Andrew J., Krishnaprasad, P.S.
This report details the objectives, methodologies, and results for Phase II ofthe project, "Modeling and Optimization for Epitaxial Growth"(see~cite{NKPB98} for Phase I report). This project is a...
Nilpotentization and Motion Control for Under-Actuated Systems on Matrix Lie Groups (1999)
Herbert Struemper, P. S. Krishnaprasad
In this paper we consider under-actuated, drift-free, invariant systems on matrix Lie groups and show how motion control results for nilpotent systems can be extended to invariant systems on...
Computation for Nonlinear Balancing (1998)
Newman, Andrew J., Krishnaprasad, P. S.
We illustrate a computational approach to practicalnonlinear balancing via the forced damped pendulum example.
Characterization of an ETREMA MP 50/6 Magnetostrictive Actuator (1998)
Venkataraman, R., Rameau, J., Krishnaprasad, P. S.
This report presents the Displacement (Strain)-Current characteristic of an ETREMA MP 50/6 magnetostrictive actuator. This actuator is made of TERFENOL-D and displays giant magnetostriction. The...
The Hybrid Motor Prototype: Design Details and Demonstration Results (1998)
Venkataraman, R., Dayawansa, Wijesuriya P., Krishnaprasad, P.S.
A novel hybrid rotary motor incorporating piezoelectric and magnetostrictive actuators has been designed and demonstrated. The novelty of this motor was the creation of an electrical resonant...
A Lyapunov Functional for the Cubic Nonlinearity Activator-Inhibitor Model Equation (1998)
Justh, Eric W., Krishnaprasad, P.S.
The cubic nonlinearity activator-inhibitor model equation is a simpleexample of a pattern-forming system for which strong mathematical resultscan be obtained. Basic properties of solutions and the...
A Model for a Thin Magnetostrictive Actuator (1998)
Venkataraman, R., Krishnaprasad, P.S.
In this paper, we propose a model for dynamic magnetostrictive hysteresisin a thin rod actuator. We derive two equations that representmagnetic and mechanical dynamic equilibrium. Our model results...
Kantor, George A., Krishnaprasad, P.S.
In this paper we present a method of efficiently implementing controllers for linear systems with large numbers of sensors and actuators. It is well known that singular value decomposition can be...
Nonlinear Model Reduction for RTCVD (1998)
Newman, A., Krishnaprasad, P.S.
In this paper, we examine alternative methods for reducing thedimensionality of nonlinear dynamical system models arising incontrol of rapid thermal chemical vapor deposition (RTCVD) forsemiconductor...
Control Problems of Hydrodynamic Type (1998)
Krishnaprasad, P.S., Manikonda, V.
It has been known for some time that the classical work of Kirchhoff, Love,and Birkhoff on rigid bodies in incompressible, irrotational flows provideseffective models for treating control problems...
Oscillations, SE(2)-Snakes and Motion Control: A Study of the . . . (1998)
P.S. Krishnaprasad, Siam J. Control, D. P. Tsakiris, Motion Control
Mathematical Sciences, National Academy of Sciences, Washington D.C., (also Institute for Systems Research Technical Report 95-8, University of Maryland, College Park). P. S. Krishnaprasad & D....
Computation for Nonlinear Balancing (1998)
Andrew J. Newman, P. S. Krishnaprasad
We illustrate a computational approach to practical nonlinear balancing via the forced damped pendulum example. 1 Introduction The theory of balancing, introduced by Moore [1], was extended by...
Nonlinear Model Reduction for RTCVD (1998)
Andrew J. Newman, P. S. Krishnaprasad
In this paper, we examine alternative methods for reducing the dimensionality of nonlinear dynamical system models arising in control of rapid thermal chemical vapor deposition (RTCVD) for...
Andrew J. Newman, P. S. Krishnaprasad, Sam Ponczak, Paul Brabant
In December 1996, a project was initiated at the Institute for Systems Research (ISR), under an agreement between Northrop Grumman Electronic Sensors and Systems Division (ESSD) and the ISR, to...
Qualitative Analysis of a Bulk Ferromagnetic Hysteresis Model (1998)
R. Venkataraman, P.S. Krishnaprasad
In this paper, we present a set of equations for a bulk ferromagnetic hysteresis model. We establish the connection between this set of equations and classical energy loss expressions for...
Language, Behaviors, Hybrid Architectures and Motion Control (1997)
Manikonda, V., Krishnaprasad, P.S., Hendler, James A.
In this paper we put forward a framework that integrates features of reactive planning models with modern control-theory-based approaches to motion control of robots. We introduce a motion...
Tracking and Stabilization for Control Systems on Matrix Lie Groups (1997)
Struemper, H., Krishnaprasad, P.S.
A wide range of dynamical systems from fields as diverse as mechanics, electrical networks and molecular chemistry can be modeled by invariant systems on matrix Lie groups. This paper introduces...
Controllability of Lie-Poisson Reduced Dynamics (1997)
Manikonda, V., Krishnaprasad, P.S.
In this paper we present sufficient conditions for controllability of Lie-Poisson reduced dynamics of a class of mechanical systems with symmetry. We prove conditions (boundedness of coadjoint orbits...
Herbert Struemper, P. S. Krishnaprasad
: A wide range of dynamical systems from fields as diverse as mechanics, electrical networks and molecular chemistry can be modeled by invariant systems on matrix Lie groups. This paper extends the...
Controllability of Lie-Poisson Reduced Dynamics (1997)
Vikram Manikonda, P.S. Krishnaprasad
In this paper we present sufficient conditions for the controllability of the reduced dynamics of a class of mechanical systems with symmetry. We prove conditions (boundedness of coadjoint orbits and...
On Approximate Inversion and Feedback Stabilization for Systems on Matrix Lie Groups (1997)
Herbert Struemper, P. S. Krishnaprasad
This paper studies open-loop tracking and feedback stabilization for nonholonomic systems. Using the concept of approximate inversion, results for drift-free, leftinvariant systems on specific matrix...
Herbert Struemper, P. S. Krishnaprasad
: A wide range of dynamical systems from fields as diverse as mechanics, electrical networks and molecular chemistry can be modeled by invariant systems on matrix Lie groups. This paper extends the...
On Approximate Inversion and Feedback Stabilization for Systems on Matrix Lie Groups (1997)
Herbert Struemper, P. S. Krishnaprasad
This paper studies open-loop tracking and feedback stabilization for nonholonomic systems. Using the concept of approximate inversion, results for drift-free, leftinvariant systems on specific matrix...
Nonholonomic Mechanical Systems with Symmetry (1996)
Krishnaprasad, P.S., Bloch, Anthony M., Marsden, Jerrold E., Murray, Richard M.
This work develops the geometry and dynamics of mechanical systems with nonholonomic constraints and symmetry from the perspective of Lagrangian mechanics and with a view to control-theoretical...
Nonholonomic mechanical systems with symmetry (1996)
Bloch, Anthony M., Murray, Richard M., Marsden, Jerrold E., Krishnaprasad, P. S.
This work develops the geometry and dynamics of mechanical systems with nonholonomic constraints and symmetry from the perspective of Lagrangian mechanics and with a view to control-theoretical...
The Euler-Poincaré equations and double bracket dissipation (1996)
Ratiu, Tudor S., Krishnaprasad, P. S., Bloch, Anthony M., Marsden, Jerrold E.
This paper studies the perturbation of a Lie-Poisson (or, equivalently an Euler-Poincaré) system by a special dissipation term that has Brockett's double bracket form. We show that a formally...
Justh, Eric W., Krishnaprasad, P.S., Kub, F.J.
The physical motivation and rigorous proof of convergence for a particular network of nonlinear coupled oscillators are reviewed. Next, the network and convergence proof are generalized in several...
A Wavelet Approach to Wafer Temperature Measurement via Diffuse Reflectance Spectroscopy (1996)
Krishnaprasad, P.S., Kugarajah, T., Dayawansa, Wijesuriya P.
A methodology for the determination of wafer temperature in Molecular Beam Epitaxy via diffuse reflectance measurements is developed. Approximate physical principles are not used, instead, patterns...
The Euler-Poincaré equations and double bracket dissipation (1996)
Bloch, Anthony M., Krishnaprasad, P. S., Marsden, Jerrold E., Ratiu, Tudor S.
The Euler-Poincar'e Equations and Double Bracket Dissipation (1996)
Anthony Bloch, P. S. Krishnaprasad, Jerrold E. Marsden, Tudor S. Ratiu
This paper studies the perturbation of a Lie-Poisson (or, equivalently an Euler-Poincaré) system by a special dissipation term that has Brockett’s double bracket form. We show that a formally...
Nonholonomic mechanical systems with symmetry (1996)
Anthony M. Bloch, P. S. Krishnaprasad, Jerrold E. Marsden, Richard M. Murray, Communicated P. Holmes
Dynamics and Controllability of a Planar Rigid Body with a Thruster (1996)
Vikram Manikonda, P.S. Krishnaprasad
In this paper we discuss the dynamics of a planar rigid body with a thruster. We identify the position and orientation of the planar rigid body with an element of the Lie group SE(2). The invariance...
Nonholonomic Mechanical Systems with Symmetry (1996)
Anthony M. Bloch, P.S. Krishnaprasad, Jerrold E. Marsden, Richard M. Murray
This work develops the geometry and dynamics of mechanicalsystems with nonholonomic constraints and symmetry from the perspective of Lagrangian mechanics and with a view to control theoretical...
Nonholonomic mechanical systems with symmetry (1996)
Anthony M. Bloch, P. S. Krishnaprasad, Jerrold E. Marsden, Richard M. Murray, Communicated R Holmes
Abstract......................................... 21
Nonholonomic Mechanical Systems with Symmetry (1995)
Bloch, A. M., Krishnaprasad, P. S., Marsden, J. E., Murray, R. M.
This work develops the geometry and dynamics of mechanical systems with nonholonomic constraints and symmetry from the perspective of Lagrangian mechanics and with a view to control theoretical...
Motion Control and Coupled Oscillators (1995)
It is remarkable that despite the presence of large numbers of degrees of freedom, motion control problems are effectively solved in biological systems. While feedback, regulation and tracking have...
Manikonda, V., Krishnaprasad, P.S., Hendler, James A.
This paper puts forward a formal basis for behavior-based robotics, using techniques that have been successful in control- theory-based approaches for steering and stabilizing robots that are subject...
Oscillations, SE(2)--snakes and motion control (1995)
P. S. Krishnaprasad, D. P. Tsakiris
This paper is concerned with the problem of motion generation via cyclic variations in selected degrees of freedom (usually referred to as shape variables) in mechanical systems subject to...
Smart Motor Concept Based on Piezoelectric-Magnetostrictive Resonance (1995)
Venkataraman Krishnaprasad, R. Venkataraman, P. S. Krishnaprasad, W. P. Dayawansa, J. Loncaric
In this paper, we discuss a smart motor concept, in which piezoelectric and magnetostrictive actuators forming a resonance electric circuit function together to produce bidirectional motion of a...
Oscillations, SE(2)-Snakes and Motion Control (1995)
P. S. Krishnaprasad, D. P. Tsakiris
This paper is concerned with the problem of motion generation via cyclic variations in selected degrees of freedom (usually referred to as shape variables) in mechanical systems subject to...
Formalizing Behavior-based Planning for Nonholonomic Robots (1995)
Vikram Manikonda, James Hendler, P. S. Krishnaprasad
In this paper we present a formalization of behavior-based planning for nonholonomic robotic systems. This work provides a framework that integrates features of reactive planning models with modern...
Vikram Manikonda, P.S. Krishnaprasad, James Hendler
This paper puts forward a formal basis for behaviorbased robotics, using techniques that have been successful in control-theory-based approaches for steering and stabilizing robots that are subject...
Motion Control of Drift-Free, Left-Invariant Systems on Lie Groups (1995)
Naomi Ehrich Leonard, P. S. Krishnaprasad
In this paper we address the constructive controllability problem for drift-free, leftinvariant systems on finite-dimensional Lie groups with fewer controls than state dimension. We consider small...
Motion Control of Drift-Free, Left-Invariant Systems on Lie Groups (1994)
Leonard, N.E., Krishnaprasad, P.S.
In this paper we address the constructive controllability problem for drift free, left-invariant systems on finite-dimensional Lie groups with fewer controls than state dimension. We consider small...
Leonard, N.E., Krishnaprasad, P.S.
In this paper we present a general algorithm for constructing open-loop controls to solve the complete constructive controllability problem for drift-free invariant systems on Lie groups that satisfy...
G-Snakes: Nonholonomic Kinematic Chains on Lie Groups (1994)
Krishnaprasad, P.S., Tsakiris, D.P.
We consider kinematic chains evolving on a finite-dimensional Lie group G under nonholonomic constraints, where snake-like global motion is induced by shape variations of the system. In particular,...
HControl for Impulsive Disturbances: A State-Space Solution (1994)
Wei, Q.F., Dayawansa, Wijesuriya P., Krishnaprasad, P.S.
In this paper we formulate and study an interesting (sub) optimal Hcontrol problem related to the attenuation of impulsive disturbances to a class of linear systems. Among the motivating factors...
Dissipation induced instabilities (1994)
Bloch, Anthony M., Krishnaprasad, P. S., Marsden, Jerrold E., Ratiu, Tudor S.
Dissipation induced instabilities (1994)
Anthony Bloch, P. S. Krishnaprasad, Jerrold E. Marsden, Tudor S. Ratiu
The main goal of this paper is to prove that if the energy-momentum (or energy-Casimir) methodpredicts formal instability of a relative equilibrium in a Hamiltonian system with symmetry, then with...
G-Snakes: Nonholonomic Kinematic Chains on Lie Groups (1994)
P. S. Krishnaprasad, D. P. Tsakiris
We consider kinematic chains evolving on a nite{ dimensional Lie group G under nonholonomic constraints, where snake{like global motion is induced by shape variations of the system. In particular, we...
The Euler-Poincaré Equations and Double Bracket Dissipation (1994)
Anthony Bloch, P. S. Krishnaprasad, Jerrold E. Marsden, Tudor S. Ratiu
This paper studies the perturbation of a Lie-Poisson (or, equivalently an Euler-Poincaré) system by a special dissipation term that has Brockett's double bracket form. We show that a formally...
2-Module Nonholonomic Variable Geometry Truss Assembly: Motion Control (1994)
P. S. Krishnaprasad, D. P. Tsakiris
: The nonholonomic motion planning problem is considered for a novel class of modular mobile manipulators, where each module is implemented as a planar parallel manipulator with idler wheels. This...
Adaptive Nonlinear Approximations (1994)
Geoffrey Davis, P. S. Krishnaprasad, Orthogonal Matching Pursuit, W. H. Press, S. A. Teukolsky, ...
0.23> Bulletin of the American Mathematical Society, Vol. 21, No. 1, 1-46, July 1989. [54] P. Switzer, "Numerical classification," in Geostatistics, Plenum, New York, 1970. [55] ,...
Control of Switched Electrical Networks Using Averaging on Lie Groups (1994)
Naomi Ehrich Leonard, P.S. Krishnaprasad
In this paper we apply the theory of averaging and motion control on Lie groups [1] to the problem of controlling energy transfers between dynamic storage elements in switched electrical networks....
G-Snakes: Nonholonomic Kinematic Chains On Lie Groups (1994)
P.S. Krishnaprasad, D. P. Tsakiris
We consider kinematic chains evolving on a finite-- dimensional Lie group G under nonholonomic constraints, where snake--like global motion is induced by shape variations of the system. In...
An Improved Model for the Dynamics of Spur Gear Systems with Backlash Consideration (1993)
Shing, T.K., Tsai, L.W., Krishnaprasad, P.S.
An improved model which accounts for backlash effects is proposed for the dynamics of spur gear systems. This dynamic model is mainly developed for the purpose of real time control. The complicated...
Averaging and Motion Control On Lie Groups (1993)
Leonard, N.E., Krishnaprasad, P.S.
The deeper investigation of problems of feedback stabilization and constructive controllability has drawn increased attention to the question of structuring control systems. Thus, for instance, it is...
Optimal Control of a Rigid Body with Two Oscillators (1993)
Yang, R., Krishnaprasad, P.S., Dayawansa, Wijesuriya P.
This paper is concerned with the exploration of reduction and explicit solvability of optimal control problems on principal bundles with connections from a Hamiltonian point of view. The particular...
High-Order Averaging on Lie Groups and Control of an Autonomous Underwater Vehicle (1993)
Leonard, N.E., Krishnaprasad, P.S.
In this paper we extend our earlier results on the use of periodic forcing and averaging to solve the constructive controllability problem for drift-free left-invariant systems on Lie groups with...
Modeling of Impact on a Flexible Beam (1993)
Wei, Q.F., Krishnaprasad, P.S., Dayawansa, Wijesuriya P.
We consider the problem of modeling dynamical effects of impact of an elastic body on a flexible beam. We derive a nonlinear integral equation by using the Hertz law of impact in conjunction with the...
Optimal Control and Poisson Reduction (1993)
In this paper we make explicit a reduction of G-invariant optimal control problems on a Lie group G.
Nonholonomic Variable Geometry Truss Assemblies I: Motion Control (1993)
Krishnaprasad, P.S., Tsakiris, D.P.
We consider the nonholonomic motion planning problem for a novel class of snakelike modular mobile manipulators, where each module is implemented as a planar parallel manipulator with idler wheels....
Averaging for Attitude Control and Motion Planning (1993)
Naomi Ehrich Leonard, P.S. Krishnaprasad
In this paper we show how to use periodic forcing to solve the constructive controllability problem for drift-free, leftinvariant systems on matrix Lie groups with fewer controls than states. In...
Y. C. Pati, R. Rezaiifar, P. S. Krishnaprasad
In this paper we describe a recursive algorithm to compute representations of functions with respect to nonorthogonal and possibly overcomplete dictionaries of elementary building blocks e.g. affine...
Pati Rezaiifar, Y. C. Pati, R. Rezaiifar, P. S. Krishnaprasad
In earlier work [Pati and Krishnaprasad 1992] it was shown that rational wavelet frame decompositions of the Hardy space H 2 (\Pi + ) may be used to efficiently capture time-frequency localized...
On the Geometry and Dynamics of Floating Four-Bar Linkages (1992)
In this paper, we investigate the kinematics and dynamics of floating, planar four-bar linkages. The geometry of configuration space is analyzed through the classical theory of mechanisms due to...
Affine Frames of Rational Wavelets in H2 (II+) (1992)
Pati, Y.C., Krishnaprasad, P.S.
In this paper we investigate frame decompositions of H2(II+) as a method of constructing rational approximations to nonrational transfer functions in H2(II+). The frames of interest are generated...
Dissipation Induced Instabilities (1992)
Bloch, Anthony M., Krishnaprasad, P.S., Marsden, Jerrold E., Ratiu, Tudor S.
The main goal of this paper is to prove that if the energy- momentum (or energy-Casimir) method predicts formal instability of a relative equilibrium in a Hamiltonian system with symmetry, then with...
Adaptive Friction Compensation for Bi-Directional Low-Velocity Position Tracking (1992)
Leonard, N.E., Krishnaprasad, P.S.
This paper presents a comparative investigation of friction- compensating control strategies designed to improve low-velocity position tracking performance in the presence of velocity reversals for...
Almost Poisson Integration of Rigid Body Systems (1991)
Austin, Mark, Krishnaprasad, P.S., Wang, L.S.
In this paper we discuss the numerical integration of Lie-Poisson Systems using the mid-point rule. Since such systems result from the reduction of hamiltonian systems with symmetry by Lie Group...
Mechanical Systems with Partial Damping: Two Examples (1991)
Wang, L.S., Krishnaprasad, P.S., Dayawansa, Wijesuriya P.
We discuss the problem of constructing steady state motions of mechanical systems with partial damping. A planar three bar linkage with viscous damping at one of the joints is considered as an...
Steady Rigid-Body Motions in a Central Gravitational Field (1991)
Wang, L.S., Maddocks, J.H., Krishnaprasad, P.S.
In recent work, the exact dynamic equations for the motion of a finite rigid body in a central gravitational field were shown to be of Hamiltonian form with a noncanonical structure. In this paper,...
Gyroscopic Control and Stabilization (1991)
Wang, L.S., Krishnaprasad, P.S.
In this paper, we consider the geometry of gyroscopic systems with symmetry, starting from an intrinsic Lagrangian viewpoint. We note that natural mechanical systems with exogenous forces can be...
Geometric Phases, Anholonomy, and Optimal Movement (1991)
In the search for useful strategies for movement of robotic systems (e.g. manipulators, platforms) in constrained environments (e.g. in space, underwater), there appear to be new principles emerging...
Comparative Study of Friction-Compensating Control Strategies for Servomechanisms (1991)
Leonard, N.E., Krishnaprasad, P.S.
This paper describes a comparative investigation of friction- compensating control strategies designed to improve low-velocity position tracking performance for servomechanisms. Several control...
Hamiltonian Dynamics of a Rigid Body in a Central Gravitational Field (1990)
Wang, L.S., Krishnaprasad, P.S., Maddocks, J.H.
This paper concerns the dynamics of a rigid body moving under the influence of a central gravitational field. Explicit account is taken of effects arising because of the finite extent of the body....
A Multibody Analog of Dual-Spin Problems (1990)
Wang, L.S., Krishnaprasad, P.S.
In the field of spacecraft altitude control and stabilization, the dual-spin maneuver has an important place. Here, we consider a problem which is a multibody analog of the dual-spin problem. The...
On the Dynamics of Floating Four-Bar Linkages. II. Bifurcations of Relative Equilibria (1990)
Continuing our program to understand the geometry and dynamics of floating four-bar linkages, we explore the relative equilibria of an assembly that admits symmetric configurations. We show that a...
Geometric Phases, and Optimal Reconfiguration for Multibody Systems (1990)
Relative Motion in a system of coupled rigid bodies can yield global reorientation (or phase shift.) We give a formula to compute such a phase shift and interpret the same in geometric terms. The...
Pati, Y.C., Krishnaprasad, P.S.
In this paper we develop a theoretical description of standard feedfoward neural networks in terms of discrete affine wavelet transforms. This description aids in establishing a rigorous...
Stabilization of Rigid Body Dynamics by Internal and External Torques (1990)
Bloch, Anthony M., Krishnaprasad, P.S., Marsden, Jerrold E.
In this paper we discuss the stabilization of the rigid body dynamics by external torques (gas jets) and internal torques (momentum wheels). We compare the stabilizing quadratic quadratic feedback...
Eulerian Many-Body Problems. (1989)
The hamiltonian dynamics of coupled structures is discussed. There are geometric parallels in earlier work on the Newtonian (gravitational) many-body problem. In the study of relative equilibria, a...
Relative Equilibria for Two Rigid Bodies. (1989)
Wang, L.S., Krishnaprasad, P.S.
For simple mechanical systems with symmetry, a variational principle on configuration space determines relative equilibria. Here, this principle of symmetric criticality is applied to a problem of...
On the Dynamics of Floating Four-Bar Linkages. (1989)
The hamiltonian structure of floating, planar four-bar linkages is discussed. The geometry of configuration space is related to the classical theory of mechanisms due to Grashof. For generic value of...
Neural Network Solutions to Problems in 'Early Taction'. (1989)
Pati, Y.C., Krishnaprasad, P.S., Peckerar, M.C.
In this paper we examine the application of artificial neural networks to low level processing of tactile sensory data. In analogy to the term early msion, we call the first level of processing...
Multibody Simulation in an Object Oriented Programming Environment. (1988)
Sreenath, N., Krishnaprasad, P.S.
A multibody system simulation architecture capable of generating the dynamical equations of the multibody system symbolically, automatically create the computer code to simulate these equations...
Oh, Y.G., Sreenath, N., Krishnaprasad, P.S., Marsden, J.E.
Part I of this paper, namely Sreenath, Oh, Krishnaprasad, and Marsden [1987], hereafter denoted [I], studied the Hamiltonian structure and equilibria for interconnected planar rigid bodies, with the...
The Second Synthetic Microstructures in Biological Research Conference. (1988)
Peckerar, M., Krishnaprasad, P.S., Shamma, S.A.
Not available.
Simo, J.C., Marsden, J.E., Krishnaprasad, P.S.
ABSTRACT NOT AVAILABLE.
The Dynamics of Two Coupled Rigid Bodies. (1987)
Grossman, R., Krishnaprasad, P.S., Marsden, J.E.
In this paper we derive a Poisson bracket on the phase space so(3)*x so(3)*x S0(3) such that the dynamics of two three- dimensional rigid bodies coupled by a ball and socket joint can be written as a...
Posbergh, T.A., Krishnaprasad, P.S., Marsden, J.E.
We consider a system consisting of a rigid body to which a linear extensible shear beam is attached. For such a system the Energy- Casimir method can be used to investigate the stability of the...
Neural Networks for Tactile Perception. (1987)
Pati, Y.C., Friedman, Daniel E., Krishnaprasad, P.S., Yao, C.T., Peckar, M.C., Yang, R., ...
Integrated tactile sensors appear to be essential for dextrous control of multifingered robotic hands. Such sensors would feature (1) compliant contact surfaces, (2) high resolution surface stress...
Tactile Sensing and Inverse Problems. (1987)
The goal of this paper is to study how a surface force profile may be estimated from the information on strain or stress distribution detected by tactile sensors. This problem is referred to as the...
Hamiltonian Structures and Stability for Rigid Bodies with Flexible Attachments. (1987)
Krishnaprasad, P.S., Marsden, J.E.
The dynamics of a rigid body with flexible attachments is studied. A general framework for problems of this type is established in the context of Poisson manifolds and reduction. A simple model for a...
The Dynamics of Coupled Planar Rigid Bodies. (1986)
Sreenath, N., Krishnaprasad, P.S., Marsden, J.E.
This paper studies the dynamics of coupled planar rigid bodies, concentrating on the case of two bodies coupled with a hinge joint. The Hamiltonian structure is non-canonical and is obtained using...
Towards a Cell Decomposition for Rational Functions (1986)
FUHRMANN, P. A., KRISHNAPRASAD, P. S.
In this paper, we investigate a decomposition of the space of reduced rational functions of fixed degree into continued fraction cells. We give a variety of combinatorial formulas pertaining to this...
DYNAMAN: A Tool for Manipulator Design and Analysis. (1985)
Sreenath, N., Krishnaprasad, P.S.
This report describes a method to formulate the dynamic equations of a robot manipulator with N links and with either revolute or prismatic joints using a Newton-Euler formulation. A general- purpose...
Geophysical Inversion and Two-Dimensional Signal Processing. (1985)
Krishnaprasad, P.S., Blankenehip, Gilmer L.
This report is motivated by the need to understand the possible applications of two-dimensional (2-D) modeling of stochastic processes and related techniques in signal processing to problems of...