Research On Modeling And Trajectory Tracking Control Of Mobile Manipulator

Mobile manipulator is the traditional manipulator installed on the mobile platform,which combines the advantages of mobile robot and manipulator.The mobile platform provides a broader working area for the manipulator,and increases the application range of the manipulator.At present,mobile robots have been widely used in traditional industrial production,aviation exploration,field exploration,domestic service and other fields.In recent years,more and more attention has been paid to this kind of system.Due to the introduction of the mobile platform,the mobile manipulator system is an incomplete redundant structure,and the mobile manipulator system becomes a highly non-linear system.The traditional PID control method is difficult to solve such problems..In this paper,the model of wheeled mobile manipulator with two links is taken as the research object,and the kinematic equation of wheeled mobile manipulator is established through the nonholonomic constraint equation.Based on the in-depth analysis of the dynamic characteristics of the system model,combined with the dynamic constraint characteristics of the nonholonomic wheeled mobile manipulator,the Lagrange functional balance method is used to establish the dynamic equation model of the system.It provides a reasonable model basis for the trajectory tracking control of the mobile manipulator.In this paper,the path planning of mobile manipulator is described in detail.The representation space method is introduced to model the space of mobile manipulator,and the space is divided into reachable and unreachable parts.In space,the change rule of the system node state at each time of the relevant variables of the mobile manipulator is obtained,and the A-star algorithm is used to search a collision free path with low power consumption.Then,a tracking controller based on extended state detector is designed to estimate and compensate the possible external interference in the tracking system of mobile manipulator.The experimental results show that the controller can compensate and counteract the external disturbance at any time,and has good trajectory tracking effect.In addition,in order to further improve the accuracy of trajectory tracking control of mobile manipulator and reduce the error.this paper uses boundary layer method and improved exponential reaching law to innovate the sliding mode variable structure control strategy,and designs a new trajectory tracking controller.The experimental results show that the improved sliding mode control strategy can not only achieve the desired trajectory tracking effect of the manipulator,but also has strong stability and robustness,and can significantly reduce the chattering of the system,or even eliminate the chattering of the system.