In the paper,we exhibit the usefulness of nonlinearity in two aspects:analysis of nonlinear dynamics and nonsmooth feedback *** illustrative examples are given to show how the new bifurcation p
In the paper,we exhibit the usefulness of nonlinearity in two aspects:analysis of nonlinear dynamics and nonsmooth feedback *** illustrative examples are given to show how the new bifurcation p
In this paper, a learning-based feedforward term is developed to solve a general control problem in the presence of unknown nonlinear dynamics with a known period. Since the learning-based feedforward term is generate...
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In this paper, a learning-based feedforward term is developed to solve a general control problem in the presence of unknown nonlinear dynamics with a known period. Since the learning-based feedforward term is generated from a straightforward Lyapunov-like stability analysis, the control designer can utilize other Lyapunov-based design techniques to develop hybrid control schemes that utilize learning-based feedforward terms to compensate for periodic dynamics and other Lyapunov-based approaches (e.g., adaptive-based feedforward terms) to compensate for non-periodic dynamics. To illustrate this point, a hybrid adaptive/learning control scheme is utilized to achieve global asymptotic link position tracking for a robot manipulator.
We consider the regulation control problem for a two-degree-of-freedom (2-DOF), underactuated overhead crane system. Inspired by recently designed passivity-based controllers for underactuated systems, we design sever...
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We consider the regulation control problem for a two-degree-of-freedom (2-DOF), underactuated overhead crane system. Inspired by recently designed passivity-based controllers for underactuated systems, we design several controllers that asymptotically regulate the gantry position and payload position. Specifically, utilizing LaSalle's invariance set theorem, we first illustrate how a simple proportional-derivative (PD) controller can be utilized to asymptotically regulate the overhead crane system. Motivated by the desire to achieve improved transient performance, we then design a two nonlinear controllers that increase the coupling between the gantry position and payload position.
The extended Kalman filter is known to have excellent filtering characteristics, but its convergence is guaranteed only if it is initialized close enough to the true state value. Numerical differentiation based observ...
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ISBN:
(纸本)0780370619
The extended Kalman filter is known to have excellent filtering characteristics, but its convergence is guaranteed only if it is initialized close enough to the true state value. Numerical differentiation based observers, on the other hand, may be designed to be globally convergent to a neighborhood of the true state value, but when the measurements are corrupted by significant uncertain signals their state estimates are delayed. In a previous work we proposed an observer design scheme for nonlinear systems which combines these two techniques to yield a globally exponentially converging observer. The necessity to implement an extended Kalman filter has two shortcomings. One is it does not apply when we face a system with an observability condition weaker than that the linearized dynamics about the estimated trajectory is completely uniformly observable. The other limitation is the computation burden. In this paper we propose an alternative which is still a global exponential observer. While the computation burden may not have been significantly reduced, definitely, it applies to a wider class of nonlinear systems. Noteworthy we prove that this global exponential observer is also bounded which is a feature the nonlinear observers in the literature rarely possess. The observer scheme is illustrated through a bioprocess example whose linearization is not completely uniformly observable.
作者:
F. PlestanJ.W. GrizzleE.R. WesterveltG. AbbaIRCCyN
Ecole Centrale Université et Ecole des Mines de Nantes CNRS BP 92101 1 rue de la Noë 44321 Nantes cedex 03 France Control Systems Laboratory
Electrical Engineering and Computer Science Department University of Michigan Ann Arbor MI 48109-2122 USA LGIPM
Université de Metz IUT de Thionville Espace Cormontaigne 57970 Yutz France
The goal is to demonstrate a means to prove asymptotically stable walking in a planar, under actuated, five-link biped robot model. The analysis assumes a rigid contact model when the swing leg impacts the ground and ...
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The goal is to demonstrate a means to prove asymptotically stable walking in a planar, under actuated, five-link biped robot model. The analysis assumes a rigid contact model when the swing leg impacts the ground and an instantaneous double-support phase: under theses hypotheses, the robot is modeled by a dynamic nonlinear system and an impulse model. The controller induces finite-time stabilization of four of the robot's five degrees of freedom, resulting in a reduced Poincaré stability analysis that can be carried out by computing a one dimensional map.
We seek to build CIS research systems within a flexible, open architecture. In this paper, we outline our solutions to the problems of system design, construction, and integration in this environment: building distrib...
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Two robust adaptive control schemes (state-feedback and output-feedback) for formationkeeping of a pair of satellites are proposed. In contrast to most existing results, both control schemes are based on the nonlinear...
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Two robust adaptive control schemes (state-feedback and output-feedback) for formationkeeping of a pair of satellites are proposed. In contrast to most existing results, both control schemes are based on the nonlinear model directly, not on the simplified linearized model. In addition, the uncertainties and disturbances in the system such as the effects due to solar pressure, noncentral gravitational field, air drag, etc. are all considered. The objective of the control design is to force the relative position between two satellites to track a given reference signal while maintaining the desired Keplerian trajectory (in this case circular) for the master satellite. The results of this paper may be easily generalized to formationkeeping of a number of satellites.
This paper proposes a factorization method that reconstructs camera motion and scene shape based on the matching of multiple images under the condition that the camera captures a perspective view. Starting from the af...
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This paper proposes a factorization method that reconstructs camera motion and scene shape based on the matching of multiple images under the condition that the camera captures a perspective view. Starting from the affine projection camera model, the projection depth is iteratively estimated until the measurement matrix has rank 4. Then, the obtained measurement matrix is factorized to restore the three-dimensional information of the scene in the projection space. This approach eliminates noise sensitive processes, such as the calculation of the fundamental matrix, that are required in the factorization for the conventional perspective projection image, and a stable reconstruction is realized. Furthermore, the metric constraint in the conventional affine model is extended, and the metric constraint in the perspective projection condition is derived. It is shown that the reconstruction in Euclidean space is realized if the internal parameters of the camera are given.
In many embedded control system applications, the control algorithm includes both logical and data flow portions. We apply formal methods of system verification to discrete-state algorithms. Specifically, we make use ...
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ISBN:
(纸本)0780365666
In many embedded control system applications, the control algorithm includes both logical and data flow portions. We apply formal methods of system verification to discrete-state algorithms. Specifically, we make use of a formal model checking tool to prove or disprove various properties of the algorithm. Questions pertaining to the achievability of states and paths and proper variable assignment are cast as logical assertions in computation tree logic (CTL), and evaluated using the model checker. In addition, we describe an approach for generating scenarios; that is, a sequence of inputs and parameters that will take a discrete-state system model through a given sequence. We present several examples illustrating various questions that the designer may wish to pose, and an appropriate CTL assertion for each.
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