Font Size: a A A

Research On Terminal Sliding Mode Control Of Manipulators Based On Observer

Posted on:2024-02-07Degree:MasterType:Thesis
Country:ChinaCandidate:E Q ZhaoFull Text:PDF
GTID:2568307157499914Subject:Electronic information
Abstract/Summary:PDF Full Text Request
As an important branch of robot control,robotic manipulators has been widely used in aerospace,military reconnaissance,medical treatment,industrial manufacturing and other fields.The study of robotic manipulators control technology has become one of the most popular research hotspots for researchers.With the increasingly fierce competition in the industry,it is more difficult for robotic manipulators to replace labor to complete some high-intensity,high-risk and highly repetitive tasks.In order to satisfy the complex and diverse task requirements by further improving the robotic manipulators trajectory tracking control performance.Therefore,the research on high performance trajectory tracking control method of robotic manipulators has important practical application value and practical significance.Because the robotic system is a class of multivariable,strongly coupled and highly nonlinear complex dynamic system,there are dynamic modeling errors and unknown external environment disturbances in the actual control process,which makes it difficult to establish an accurate dynamics model and increases the difficulty of trajectory tracking control for the robotic manipulators.Therefore,this paper focuses on this control problem and takes the robotic manipulators as the research object.Based on sliding mode control algorithm,finite/fixed time control theory,disturbance observer design and other techniques,the practical problems such as modeling errors,unknown external disturbances,actuator input saturation constraints,and system convergence time are considered into the design of the trajectory tracking control algorithm to study the trajectory tracking control problem for robotic manipulators.The specific research work includes the following aspects:(1)In order to solve the problems of modeling errors and unknown external disturbances in the robotic manipulators system,a non-singular fast terminal sliding mode control scheme based on nonlinear disturbance observer is designed.By using disturbance observer,the total disturbance of the system is accurately estimated,then designing appropriate gain functions to enhance the exponential convergence of the disturbance observation error and achieve feedforward compensation for the controller.Considering the singularity problem existing in the terminal sliding mode,a non-singular fast terminal sliding mode controller is expressed based on disturbance observer,which can guarantee the finite-time convergence of tracking errors and alleviate the effect of chattering of the controller output.In addition,in the process of controller design,using a smoother nonlinear function instead of a discontinuous function is helpful to reduce the chattering influence,which is beneficial to improve the system stability and tracking accuracy.Finally,the effectiveness of the proposed strategy is further verified by simulation comparison.(2)A novel fixed-time nonsingular terminal sliding mode trajectory tracking control scheme based on an extended state observer is proposed for uncertain robotic manipulators with input saturation constraint problem.A double power fixed-time extended state observer(FXESO)is designed to estimate the lumped disturbances,including modeling errors and external disturbances,and their estimation errors converge to the origin in fixed time.To solve the saturation problem of an actuator,a new fixed-time convergent auxiliary system is built to compensate for input saturation,and a Gaussian error function is introduced to approximate the input saturation constraints model.Then,based on the FXESO and auxiliary dynamic system,a fixed-time nonsingular terminal sliding mode controller is constructed,and piecewise continuous functions are adopted in the controller design to avoid the singularity problem.Finally,the fixed-time stability of the entire closed-loop system is demonstrated by Lyapunov theory.Comparative simulations are carried out to illustrate the effectiveness and superiority of the proposed approach.
Keywords/Search Tags:Manipulators, Sliding mode control, Input saturation, Disturbance observer, Fixed-time control
PDF Full Text Request
Related items