Research On Dynamics Simulation And Control Of Nonholonomic Wheeled Robot

With the continuous expansion of the field of science and technology and industry,intelligent robots have become an important part of the current research.Among many types of intelligent robots,wheeled mobile robots are more and more widely used because of their good motion performance and obstacle avoidance ability.However,because of its non-holonomic constraints and its vulnerability to many uncertainties in complex environments,its motion will show greater complexity,and its motion control will also be challenging.Therefore,it is of great practical significance to study the dynamic modeling,simulation and control of wheeled robot system under nonholonomic constraints.This paper mainly carries out in-depth research from the following aspects:(1)The research status of nonholonomic system dynamics and wheeled robots at home and abroad are introduced respectively.The basic structure and characteristics of wheeled robots and their modeling methods and basic theories are also introduced.It mainly includes Newton vector mechanics system and analytical mechanics system represented by Lagrange equation.Two kinds of dynamic equations in analytical mechanics system are deeply analyzed.Based on these two equations,the dynamic models of robot system are established and their dynamic behaviors are analyzed.Finally,based on the dynamic model of the system,the virtual control input is introduced to design the corresponding dynamic controller to study the trajectory tracking motion control.(2)The kinematics and dynamics models of wheeled robots are established by Routh equation,which is a common method of nonholonomic mechanics.Based on the non-sideslip state,the dynamic equation of the system is established and simulated,and the uncertainty of the system motion is visually seen.Secondly,considering the side slip of the system when the driving moment is asymmetric,the non-smooth constraint conditions and critical state of the front wheel side slip are given,and the maximum unbalanced degree of the driving moment under different friction coefficients in the critical state is explored.Finally,the critical state of sideslip is simulated again.It is found that the degree of lateral motion of the robot system is not only related to the wheel-ground friction coefficient,but also to the degree of unbalanced driving moment.When the driving moment is not balanced enough,the system will deflect and slip greatly,and the dynamic parameters will fluctuate greatly,including acceleration,velocity and displacement.(3)It is found that singular problems will occur in the later stage of dynamic simulation by using traditional Routh equation.By introducing a quasi-coordinate system with the same number of degrees of freedom,the explicit quasi-coordinate dynamic equations for holonomic and non-holonomic systems are derived by using the Gauss principle.By using these equations,the dynamics model and Simulation of the nonholonomic constrained wheeled robot are carried out.The results show that the singularity problem can be effectively avoided and the computational speed and accuracy are obviously superior.(4)In order to obtain higher accuracy and accuracy of system motion,the trajectory tracking optimization control based on system dynamics model is studied.Combining the inversion control theory and Lyapunov function,a dynamic controller with virtual control input is designed.The trajectory tracking comparison and error analysis are considered when the input signal interferes or not.The effectiveness and importance of the control are proved by system simulation.