Institute for Systems Research

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Author: search.filters.author.Dayawansa, Wijesuriya P.Subject: search.filters.subject.nonlinear systems

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Now showing 1 - 6 of 6
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    The Hybrid Motor Prototype: Design Details and Demonstration Results
    (1998) Venkataraman, R.; Dayawansa, Wijesuriya P.; Krishnaprasad, Perinkulam S.; ISR; CDCSS
    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 circuit, whereby reactive power requirement on the power source is reduced. It was envisioned that the motor would be suitable for low output speed, high torque applications because of its design. This report presents the constructional details of this motor and the results of the demonstration.
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    Non-Smooth Simultaneous Stabilization of Nonlinear Systems: Interpolation of Feedback Laws
    (1996) Ho-Mock-Qai, Bertina; Dayawansa, Wijesuriya P.; ISR
    In this paper, we introduce a method that enables us to construct a continuous simultaneous stabilizer for pairs of systems in the plane that cannot be simultaneously stabilized by smooth feedback. We extend this method to higher dimensional systems and prove that any pair of asymptotically stabilizable nonlinear systems can be simultaneously stabilized (not asymptotically) by means of continuous feedback. The resulting simultaneous stabilizer depends on a partition of unity and we show how to circumvent the computation of this partition of unity by constructing an explicit simultaneous stabilizer.
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    Optimal Control of a Rigid Body with Two Oscillators
    (1993) Yang, R.; Krishnaprasad, Perinkulam S.; Dayawansa, Wijesuriya P.; ISR
    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 mechanical system we consider is a rigid body with two driven oscillators, for which the bundle structure is (SO (3) x 者, 者, SO (3)). The optimal control problem is posed by considering a special nonholonomic variational problem, in which the nonholonomic distribution is defined via a connection. The necessary conditions for the optimal control problem are determined intrinsically by a Hamiltonian formulation. The necessary conditions admit the structure group of the principal bundle as a symmetry group of the system. Thus the problem is amendable to Poisson reduction. Under suitable hypotheses and approximations, we find that the reduced system possesses additional symmetry which is isomorphic to S1. Applying Poisson reduction again, we obtain a further reduced system and corresponding first integral. These reductions imply explicit solvability for suitable values of parameters.
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    Stabilization of Globally Noninteractive Nonlinear Systems via Dynamic State-Feedback
    (1991) Battilotti, S.; Dayawansa, Wijesuriya P.; ISR
    We consider the problem of semiglobal asymptotic stabilization and noninteracting control via dynamic state-feedback for a class of nonlinear control systems. It is assumed that the plant has been already rendered noninteractive. A sufficient condition for the stabilization of the overall system, without destroying the noninteraction property, is given in terms of stabilizability of certain subsystems.
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    Noninteracting Control with Stability for a Class of Nonlinear Systems
    (1991) Battilotti, S.; Dayawansa, Wijesuriya P.; ISR
    In this paper we address the problem of noninteracting control with stability for the class of nonlinear square systems for which noninteraction can be achieved (without stability) by means of invertible static state-feedback. The use of both static state-feedback and dynamic state-feedback is investigated. We prove that in both cases the asymptotic stabilizability of certain subsystems is necessary to achieve noninteraction and stability. We use this and some recent results to state a complete set of necessary and sufficient conditions in order to solve the problem.
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    Mechanical Systems with Partial Damping: Two Examples
    (1991) Wang, L.S.; Krishnaprasad, Perinkulam S.; Dayawansa, Wijesuriya P.; ISR
    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 example. We show that for a generic set of system parameters all steady state motions are confined to relative equilibria. We also consider the example of two rigid bodies with one-board rotors coupled via a ball-in-socket joint with viscous friction and show that in the steady state, the system is at a relative equilibrium.