Research On Trajectory Tracking Control Of Nonholonomic Wheeled Mobile Robots

Wheeled Mobile Robot(WMR)is a system with multiple functions,such as environmental awareness,dynamic decision-making and planning,behavior control and execution,etc.It is an important field of robot research.Benefiting from the development of robotics,WMR has more and more functions and functions.It can not only show its talents in industries such as industry,national defense,and service,but also work in environments that humans cannot adapt to.Non-holonomic WMR is a multi-input and multi-output nonlinear system,and it is difficult to control by smooth state feedback due to structural and unstructured uncertainties.At the same time,because non-complete WMR has greater flexibility than WMR,it has important applications in the industrial production process.Therefore,it is of great theoretical depth and practical value to study the trajectory tracking control problem of non-complete wheeled mobile robots.Based on Lyaponov stability theory and sliding mode variable structure control,this paper focuses on the kinematics model of non-holonomic wheeled mobile robot with wheel center offset and the kinematics and dynamics hybrid model of non-holonomic wheeled mobile robot.Study its trajectory tracking control.The system stability criterion is obtained by selecting the appropriate Lyapunov function and the required controller is designed.The main contents of the full text are summarized as follows:(1)For the non-holonomic wheeled mobile robot with wheel center offset,a trajectory tracking control method for improving the sliding mode is proposed.On this basis,a tracking control is proposed to ensure the global asymptotic stability.Device.Based on the sports degree attitude error model of the non-holonomic wheeled mobile robot,the design of the tracking controller is divided into two parts: The first part considers that the wheeled mobile robot has both virtual feedback variables in the X direction and the forward angle direction.This design is a switching function,and the stability analysis of the control system is carried out by Lyapunov method.The second part is the sliding mode controller design,using the exponential approach law,using the S-type exponential function instead of the symbol function,reducing the sliding mode variable structure control.The jitter caused by the design of the linear velocity and angular velocity control law makes the tracking error of the mobile robot asymptotically converge to 0,achieving global asymptotically stable tracking of the reference trajectory.(2)For the hybrid model of wheeled mobile robot kinematics and dynamics,a tracking controller with global asymptotic stability is presented,and robust adaptive compensation control is designed when the dynamic model has interference.The controller enables the wheeled mobile robot to effectively and quickly track the 8-shaped reference trajectory,and the distance error can be 0 in a very short time,which ensures the position tracking of the mobile robot in the X-axis and the Y-axis,and the linear velocity and speed tracking of angular velocity.Finally,the work of the full text is summarized.Some problems and further development directions in the research of trajectory tracking of wheeled mobile robots are pointed out,and the future research work is prospected.