Design And Application Of Finite-time Tracking Control For Nonholonomic Robot System

The development of finite-time control theory for nonlinear systems has provided an important theoretical basis for the development and application of nonholonomic systems.Compared with asymptotic stability control,finite-time control usually has faster convergence rates,higher tracking precisions,and better disturbance rejection properties.It is well known that nonholonomic systems are widely used in practical work as a branch of nonlinear systems.For example,nonholonomic mobile robots are popular as a typical case of nonholonomic systems.Therefore,in this paper,we investigate that the finite-time trajectory tracking control of nonholonomic robot systems with the help of non-singular terminal sliding mode control,backstepping,relay switching technique for a nonholonomic mobile robot systems.According to the following three parts,we describe the main research work:1.Consider the fixed-time trajectory tracking control of a kind of nonholonomic mobile robot.First,we will transforms the system model into the nonholonomic chain system by state transformation and input transformation.Secondly,the tracking control problem is transformed into the tracking error system stabilization problem by build tracking error system.Meanwhile,by utilizing the relay switching technology and a modified non-singular terminal sliding mode is constructed to ensure the convergence of the tracking error system in a fixed time.Finally,simulations and experiments are used to further demonstrate that the proposed control algorithm can achieve mobile robot fixed-time tracking control results.2.A fixed-time tracking controller is designed for a class of nonholonomic systems subject to full-state constraints.First,the control system is divided into two independence stages for the controller design by using relay switching technique.Secondly,based on the first subsystem fixedtime convergence of the first stage,the second stage is designed as a fixed-time tracking controller for the tracking error system by introducing a fixed-time filter,BLF,backstepping and dynamic surface control.At the same time,the controller is reconstructed to ensure that the system is bounded before relay switching.Finally,according to stability analysis show that the proposed control strategy can ensure the whole system converges to zero in a fixed time and comply with the predefined state constraints.3.An event-triggered finite-time tracking controller is proposed for a kind of nonholonomic systems subject to unknown disturbances.A key design idea is that the entire control system is grouped into two independent design stages by utilizing the relay switching technology,further by using nonlinear design methods to develop different finite-time tracking controllers with corresponding event-trigger rules.On the one hand,stability analysis shows that a event-triggered finite-time tracking control method is adopted to assure that the resulting closed-loop tracking error system converge to an arbitrarily small neighborhood around zero within a finite time,therefore all the closed-loop error system signals keep bounded throughout the entire control process.On the other hand,the controller is reconstructed to ensure that the system does not escape before relay switching.Finally,both simulation and experiment results are presented to illustrate the effectiveness of the proposed tracking control algorithm.