Utilization of inertial actuators, such as torque wheels, for vibration damping of a single-link flexible manipulator is considered. The torque wheel is mounted at the end effector of the manipulator to provide a bend...
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Utilization of inertial actuators, such as torque wheels, for vibration damping of a single-link flexible manipulator is considered. The torque wheel is mounted at the end effector of the manipulator to provide a bending moment at the tip for vibration suppression and pointing purposes. The torque exerted by the torque wheel at the end-effector of the manipulator is achieved through controlling the velocity of the torque wheel. A decentralized control scheme is advocated in this paper for slewing and vibration suppression. The local loop around the torque wheel is closed through feedback of the accelerometer signal at the tip. Experimental results are provided to show the effectiveness of the proposed method for end-effector positioning of flexible-link manipulators. Although the experimental results reported are for a single-link flexible manipulator, the results are applicable to the multi-link case. It may be shown that the dynamics from the voltage input to the torque wheel mounted at the tip to the tip position is minimum phase and hence invertible given that an inner-loop controller has been applied to stabilize the rigid-body motion.< >
This paper outlines some preliminary work on the stability analysis of switched and hybrid systems. The hybrid systems considered are those that combine continuous dynamics, represented by differential or difference e...
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This paper outlines some preliminary work on the stability analysis of switched and hybrid systems. The hybrid systems considered are those that combine continuous dynamics, represented by differential or difference equations, with finite dynamics usually thought of as being a finite automaton. Here, we concentrate on the continuous dynamics and model the finite dynamics as switching among finitely many continuous systems. We introduce multiple Lyapunov functions as a tool for analyzing Lyapunov stability of such "switched systems". We use iterated function systems theory as a tool for Lagrange stability. We also discuss the case where the switched systems are indexed by an arbitrary compact set.< >
A novel sonar array for mobile robots is presented with applications to localization and mapping of indoor environments. The ultrasonic sensor localizes and classifies multiple targets in two dimensions to ranges of u...
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A novel sonar array for mobile robots is presented with applications to localization and mapping of indoor environments. The ultrasonic sensor localizes and classifies multiple targets in two dimensions to ranges of up to 8 meters. By accounting for effects of temperature and humidity, the system is accurate to within 1 mm and 6.1 degrees in still air. Targets separated by 10 mm can be discriminated. Targets are classified into planes, corners, edges and unknown, with the minimum of two transmitters and two receivers. A novel approach is that receivers are closely spaced to minimize the correspondence problem of associating echoes from multiple targets. A set of templates is generated for echoes to allow the optimal arrival time to be estimated, and overlapping echoes and disturbances to be rejected.< >
This paper explores an inherent feedback limitation of using decentralized LTI control on a two-input, two-output LTI plant. The result is motivated by, and illustrated on, a reactive ion etcher.
This paper explores an inherent feedback limitation of using decentralized LTI control on a two-input, two-output LTI plant. The result is motivated by, and illustrated on, a reactive ion etcher.< >
In this paper a novel algorithm is presented for the efficient two-dimensional (2-D) symmetric noncausal finite impulse response (FIR) filtering and autoregressive (AR) modeling. Symmetric filter masks of general boun...
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In this paper a novel algorithm is presented for the efficient two-dimensional (2-D) symmetric noncausal finite impulse response (FIR) filtering and autoregressive (AR) modeling. Symmetric filter masks of general boundaries are allowed. The proposed algorithm offers the greatest maneuverability in the 2-D index space in a computational efficient way. This flexibility can be taken into advantage if the shape of the 2-D mask is not a priori known and has to be dynamically configured.< >
In this paper a fast spatial adaptive algorithm is presented for the efficient least squares (LS), autoregressive exogenous (ARX), two-dimensional (2-D) modeling. Filter masks of general boundaries are allowed. Effici...
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In this paper a fast spatial adaptive algorithm is presented for the efficient least squares (LS), autoregressive exogenous (ARX), two-dimensional (2-D) modeling. Filter masks of general boundaries are allowed. Efficient space updating recursions are developed by exploiting the spatial shift invariance property of the 2-D data set.< >
H/sub /spl infin// and robust estimation methods are discussed from a deterministic as well as a stochastic point of view. The relationship between H/sub /spl infin// and risk sensitivity for systems with known plant ...
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H/sub /spl infin// and robust estimation methods are discussed from a deterministic as well as a stochastic point of view. The relationship between H/sub /spl infin// and risk sensitivity for systems with known plant dynamics is reviewed. This relationship is extended to the more general case of estimators that are robust to noise and plant model uncertainties. Specifically, it is shown that a stochastic equivalent to the robust H/sub /spl infin// estimator exists. An example is used to compare the estimators in the deterministic sense, using the frequency response of the transfer function between the inputs and the error, as well as in the stochastic sense, using the probability density function of the output error residual.< >
Necessary and sufficient conditions for existence of estimators and controllers meeting desired H/sub /spl infin// performance criterion are given for the case where the finite sensor delays exist. A complete characte...
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Necessary and sufficient conditions for existence of estimators and controllers meeting desired H/sub /spl infin// performance criterion are given for the case where the finite sensor delays exist. A complete characterization of such controllers is also presented. The necessary and sufficient conditions are computable and are framed in terms of two algebraic Riccati equations and one finite-horizon Riccati differential equation. The controllers and estimators that are obtained here have a linear periodic structure and are easily implementable. At the foundation of these results lies a modified Nehari problem, the state space solution for which may be of independent interest.
A benchmark study of two self-organizing artificial neural network models, ART2 and DIGNET, is conducted. The architecture differences and learning procedures between these two models are compared. The performance of ...
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