Research On Coordination And Tracking Control Of Mobile Manipulator

With the continuous development of mobile robot and manipulator technology,mobile manipulator technology has been more widely studied.Compared with the base fixed manipulator,mobile manipulator has a wider operation space,while compared with mobile robot,it has the capability of manipulating the surrounding objects,and the mobile manipulator has a very wide application prospect.At present,most mobile manipulator move the manipulator and mobile base separately when the task is completed,which limits the application of the mobile manipulator.In order to achieve the simultaneous movement of manipulator and mobile base,a large number of researchers put their effort into the study of coordination and tracking control of mobile manipulator,so as to fully explore the potential of mobile manipulator.Firstly,the mobile manipulator research platforms from all over the world are investigated,the general hardware framework of mobile manipulator is summed up,and then hardware framework,software architecture and simulation environment of our mobile manipulator research platform are introduced.In order to achieve the coordination and tracking control of mobile manipulator,forward kinematics and differential kinematics of manipulator are established based on product of exponentials(PoE)method,and the inverse and forward kinematics of mobile base with wheel mounting error is established as well.The experiment results show the correctness of the models.In order to realize the coordination and tracking control of the mobile manipulator,a feedback control method with TCP transport velocity feedforward introduced is proposed in this paper based on inverse Jacobian matrix of manipulator,which can achieve the arbitrary movement of mobile base in particular region while the manipulator is tracking a particular trajectory.Experiments show that the introduction of TCP transport velocity greatly improved the response speed of the feedback control and reduces the tracking error of the end-effector.State estimation of the mobile base is critical to the accuracy and response speed of the coordination and tracking control algorithm.In this paper,the extended Kalman filter algorithm is used to integrate the odometry information and laser rangefinder observation to realize the pose estimation of the mobile base.In the end,we explore the implementation of the proposed algorithm applied to the real tasks,which show that the proposed algorithm can be applied to a variety of practical tasks.