Research On Double-layer Synchronous Predictive Control Algorithm Of Manipulator

Robotic manipulator is widely used in various industrial production because of theirs characteristics of high precision,fast response and strong versatility.In recent years,with the development of high precision machining,complex surface polishing,3D additive machining and manufacturing technology,the requirements for surface quality in industrial production have greatly improved,and higher requirements have put forward for the contour error of the end-effector of a robotic manipulator.In traditional control algorithm of robotic manipulator,the robotic manipulator is independent control of each joint,individual joint error just rely on information to regulate itself,without considering the other joints information,lead to the lack of coordination between each joint,affect the overall performance of the robotic manipulator,the large contour error is caused.In order to enhance the synchronization between the joints of the manipulator and reduce the contour error of the end-effector,this paper takes the SCARA manipulator as the research object and carries out research on the double-layered synchronous predictive control algorithm of robotic manipulator.The main contents are as follows:(1)The SCARA kinematics and dynamics is established,trajectory planning of manipulator operation space is carried out,and the simulation model and experimental platform of the manipulator are built.(2)A synchronous predictive control algorithm for manipulator based on adjacent cross coupling is proposed.Firstly,the tracking errors in joint space are transformed into synchronization errors based on adjacent cross coupling by using synchronization error transformation matrix.Secondly,the prediction model of SCARA manipulator is established.Then,a synchronous manipulator based on adjacent cross coupling is designed and its stability is analyzed.The synchronization error of joint space is taken into account in tracking control,and the output torque fluctuation of joint is reduced.Finally,simulation and experiment are carried out to verify the reliability of the controller.(3)On the basis of the synchronous predictive control of the manipulator based on adjacent cross coupling,the double-layered synchronous predictive control of the manipulator is further proposed.Firstly,the contour error of the operation space is analyzed,the definition of synchronization error based on operation space contour error model is given.Then,a double-layered synchronous predictive controller is designed for the manipulator.The controller adopts a hierarchical control structure to solve the complex control problems step by step.The controller is divided into two layers.The upper controller is responsible for generating reference trajectories for the lower controller,which takes into account the contour error at the end of the manipulator and the position and torque constraints of each joint,and the lower controller adopts the synchronous prediction controller based on adjacent cross coupling to track the reference trajectories generated by the upper controller.The controller reduces the output torque fluctuation of the joint while reducing the contour error of the endeffector of robotic manipulator and considers the joint constraints.Finally,simulation and experiment are carried out to verify the reliability of the controller.