Robust Finite-time Consensus Tracking Of Multi-robot Systems

With the continuous expansion of robot applications,the tasks and environments faced by robots are becoming more and more complex.Some complex tasks are difficult and even impossible for a single robot.Multi-robot system has great advantages in executing complex tasks because of its distribution characteristics of time,space,function,information and resources.Therefore,the research of multi-robot system has been paid close attention by researchers in various fields.The consensus problem is the basic problem of cooperative control of multi-robot systems.It has become a hot topic in the field of complex systems and control science.Since the actual system is inevitably influenced by all kinds of interference,this paper solves the finite time consensus problem of multi-robot system of all kinds of interference by designing several different finite time consensus tracking protocols.The main work includes the following aspects:(1)The finite-time stability theorem of nonlinear systems and the concepts and theorems of algebraic graph theory are introduced.For a multi-robot system with unknown nonlinear characteristics,a continuous finite-time consensus tracking protocol is designed based on the homogeneous finite-time stability theory to improve the tracking accuracy and response characteristics of the system.Without speed measurements,a nonlinear filter is used to estimate speed information online,thus the finite-time consensus tracking control problem based on output feedback is solved.(2)The problem of finite-time consensus tracking for multi-robot systems under random disturbances is studied.Due to the fact that most of the systems still have all kinds of random disturbances or uncertainties,such as actuator deviation,measurement errors,and communication topology dynamic changes,these disturbances seriously affect the performance of multi-robot system.To this end,a robust finite-time consensus tracking control based on Backstepping technique is proposed,which improves the robustness of the system.With the unknown speed information,a linear high-gain observer is used for speed estimation.A robust finite time consensus tracking protocol based on saturation function method is proposed,which avoids the "peaking" phenomenon which is not conducive to the stability of the system.The protocol can also be used for formation control of multi-robot systems.(3)In order to further improve the accuracy and robustness of the unknown state observation under the undirected graph,the second-order sliding mode observer(super-twisting algorithm)is employed to estimate the speeds of the robot online,and a finite-time consensus tracking algorithm based on super-twisting algorithm is proposed to ensure finite-time convergence of consensus tracking errors and the speed estimation errors simultaneously.The problem of finite-time consensus tracking based on output feedback is solved in the presence of random disturbances.(4)A multi-robot experiment platform based on Lab VIEW + Arduino is designed,using Lab VIEW development platform to achieve the development of real-time PC monitoring system,using multi robot individual autonomous mobile robot based on Arduino intelligent body,with complex function obstacle avoidance tracking,etc.,so as to lay the foundation for further experimental study on consensus of tracking algorithm.