Robust Predictive Control For Multiple Mobile Robots Formation

With the development of technology,single mobile robot cannot satisfy the required performance of control systems.Due to the advantages of better intelligence and adaptability,coordinated control of multiple mobile robots is becoming a hot research topic.Among all the coordinated or cooperative control problems,formation control of multiple mobile robots is a key problem which is generally considered as one of the most effective way and of both theoretical and practical significance.Although multiple mobile robots have brought so many advantages,they also bring lots of new challenging problems,such as how to establish the formation model of multiple mobile robots system,and how to design a suitable control strategy to achieve the predesigned formation.In this thesis,multiple mobile robot system is modeled as a state space model with parameter uncertainty.The centralized and distributed predictive control problems are both studied by using Lyapunov stability theory and the linear matrix inequality technology.The main works in this thesis are summarized as follows:1.A path tracking problem for single mobile robot is studied based on the tracking error kinematics model.In order to obtain the relative position between two mobile robots,the generalized arc length is introduced for formation problem of multiple mobile robots.Based on the tracking error kinematics model,centralized model and distributed model of multiple mobile robot system are both presented.2.Considering the model uncertainty caused by linearization errors,the multiple mobile robot systems is modeled as a class of centralized model with parameter uncertainty.A cooperative cost function is presented for formation problem which contains the path tracking errors and the constraint of the relative position.Then,the centralized robust predictive controller is obtained by using Lyapunov stability theory and LMI technique.The effectiveness of the proposed method is illustrated by a numerical simulation,and the results show that the proposed method can achieve the predesigned formation.3.A distributed cooperative robust predictive control algorithm is proposed for multiple mobile robot system.The proposed distributed algorithm has a lower computation burden and ahigher reliability by comparing with the centralized one.First,the constraint of the relative position is introduced for mobile robots.Then,a local optimization problem is presented with the coupling terms in the cost function.Furthermore,the local robust controller for each subsystem is obtained by using LMI technology to solve the local optimization problem.