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Research On Adaptive Control Of Non - Complete System

Posted on:2016-12-14Degree:MasterType:Thesis
Country:ChinaCandidate:X L WangFull Text:PDF
GTID:2208330464463514Subject:Operational Research and Cybernetics
Abstract/Summary:PDF Full Text Request
Since nonholonomic systems are subject to nonholonomic constraints, the classical control approaches of nonlinear systems are difficult for nonholonomic systems. The study of these systems is of great significant in both theory and application, in the event more and more researchers are devoted to new strategies. Nowadays, there are abundant results in theory. According to these theoretical results, this paper is focus on the following works:1. Adaptive tracking control of underactuated vehicles with parametric uncertainties.In this part, the tracking problem is solved for a class of underactuated vehicles. By combing kinematic constraints and the dynamical equation, a new tracking controller is designed based on the multi subsystem decomposition and construction of Lyapunov function. The controller is given firstly when the system parameters are known. An adaptive controller and a non-singular terminal sliding mode(NTSM) controller are also proposed under the condition that some parameters are uncertain. The global uniform boundedness of signals and the convergence of the tracking errors in closed-loop system are proved by Barbalat Lemma.The simulation results are presented showing effective and feasible of the proposed tracking methods.2. Finite-time adaptive tracking control for more relaxed underactuated vehicles.A further relaxed underactuated system is discussed which is an underactuated ship just with two control inputs, that is surge force and yaw moment. It is concentrated on the tracking control of trajectory and velocity in this part. The methods of subsystem decomposition and NTSM are adopted for the problem of system’s tracking control. The proposed control laws ensure the good performance of global asymptotical convergence and finite time convergence. A simulation example is provided to illustrate the feasibility of the raised control laws.3. Adaptive output feedback control for nonholonomic chained systems with i ISS inverse dynamics.This part investigates a class of nonholonomic chained systems with integral input-to-state stable(i ISS) inverse dynamics subject to unknown virtual control directions and parameter uncertainty included in drift terms. The control objective is to design an adaptive nonlinear output feedback law which solves the global asymptotic regulation for the system in question. Constructive strategies: input-state scaling transformation and backstepping technique are proposed to get around the reduced-order observer. A switching control strategy is fur-ther employed to guarantee the performance of closed-loop system. The simulation results validate the feasibility of the brought control algorithm.
Keywords/Search Tags:underactuated systems, nonholonomic chained systems, iISS inverse dynamics, subsystem decomposition, non-singular terminal sliding mode control, switching control, finitetime convergence, reduced-order observer
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