Nonholonomic System Formation Control Based On Negative Gradient Algorithm

In recent years,with the development of modern science,many disciplines like control science,artificial intelligence,computer technology have been further exchanged and integrated,the coordinated control of distributed multi-agent systems has exerted considerable influence on industrial production,transportation,aerospace and other industries.Naturally,it attracted increasing attention and research of scholars at home and abroad,formation control is one of the hot topics in coordinated control of distributed multi-agent systems.In this thesis,the problem of formation control which based on relative distance and angle information in nonholonomic system is studied.Aiming at the nonholonomic vehicle system with unknown disturbance,a triangular formation control strategy of adaptive perturbation method is proposed based on negative gradient algorithm,it eliminates the impact of system errors and guarantees the global exponential stability of multi-agent systems.Furthermore,we extend the above method to nonholonomic system with n agents,and then the stability of the nonholonomic formation system which based on relative distance and angle information are analyzed.The analysis tools used in this paper are mainly topological graph theory,Barbalat's lemma and non-smooth analysis theory.The main work of the thesis is as follows:Firstly,the undirected formation control of three agents for the nonholonomic system is studied.In the nonholonomic system with unknown disturbances,we add perturbation in the direction of any agent based on potential energy function.Then adaptive method is used to estimate unknown upper bound of the disturbance,and the negative gradient algorithm is introduced to design the formation control law.Therefore,the nonholonomic system can converge to the unique desired equilibrium state at an exponential speed,the wheeled vehicle will achieve to desired formation without collision.Secondly,the rigid formation control of n agents for the perturbed nonholonomic system is investigated.In nonholonomic system with unknown disturbances,the new adaptive perturbation method is designed on relative distance information between communicating agents and the asymptotic stability of the multi-agent formation system is proved by non-smooth analysis theory.So that the multi-agent system can not only achieve the desired formation,but also appeal no collision between any communicating vehicles,the translational and rotational velocities of all agents will tend to zero.Thirdly,the nonholonomic formation control based on only angle measurement information is considered.In view of the limitations of the actual measurement environment and practical applications,the formation control strategy is designed using only the angle information between communicated agents in nonholonomic system with n agents.Then we introduce potential energy function method to design control law,and employ nonlinear theory and non-smooth analysis theory to perform stability analysis.This algorithm can ensure the desired relative angle between communicating agents,thus the closed-loop formaton system can converge to the desired formation.Finnally,The effectiveness of the formation control algorithm is verified by simulation for triangulation formation control?rigid formation control based on distance and only angle information formation control in nonholonomic system.