Frequency-domain modeling of nonlinear multivariable systems

Design of Nonlinear Lead and/or Lag Compensators

Abstract: A known nonlinear compensator design approach is adapted to allow design of nonlinear lead and/or lag compensators, and a number of MATLAB functions are developed that automate the compensator design procedure. With this design tool, control engineers would be able to rapidly design nonlinear lead and/or lag compensators. An example of a tutorial nature is presented.

Control of Automotive Semi-Active MR Suspensions for In-Wheel Electric Vehicles

Abstract: In this work, four different semi-active controllers for a quarter of vehicle and full vehicles are evaluated and compared when used in internal combustion engine (ICE) vehicles vs electric vehicles (EVs) with in-wheel motor configuration as a way to explore the use of semi-active suspension systems in this kind of EVs First, the quarter of vehicle vertical dynamics is analyzed and then a full vehicle approach explores the effectiveness of the control strategies and the effects of the traction in the vertical Control performances Aspects like the relation between traction and suspension performances, and the resonance frequencies are also discussed

Time-Domain Synthesis of Dual-Range Controller For Use With Nonlinear Systems

Abstract: In this paper we present a new procedure for synthesis of dual-range linear controllers for use with nonlinear systems as well as linear systems with integrity. The procedure uses a factorization approach coupled with nonlinear optimization. The procedure is demonstrated by solving an example problem.

Computer-aided design of nonlinear H ∞ controllers using describing functions

Abstract: A computer-aided procedure for design of nonlinear Hinfin controllers for nonlinear plants, whose dynamic and static behavior are highly sensitive to the amplitude level of excitation, is presented The procedure is based on describing function concepts involving sinusoidal input describing function models of the nonlinear plant, and it includes an application of a newly developed inverse describing function technique to arrive at nonlinear gains of the Hinfin controller The procedure is applied to a servomechanism problem to demonstrate the typical results that may be achieved

Tracking and decoupling of multivariable nonlinear systems

Abstract: The purpose of this paper is to present a new systematic procedure for decoupling and command tracking of multivariable, nonlinear, and unstable systems. The design methodology is based on stabilization of the multivariable system followed by generating its describing function models; two algebraic procedures for decoupling and tracking are utilized. Finally, the design must be verified by a nonlinear simulation to make sure that approximations made during design are valid. This is the first paper in the area of simultaneous decoupling and signal tracking of multivariable nonlinear systems that is based on the application of the describing function technique and two other algebraic techniques.