Research On The Controlling Method Of A Collaborative Robot Based On Real-time Ethernet Technology

Co-robotics,has been a hot topic in the research field of industrial robot.The trajectory teaching is quite complicated for tradition robots,and much professional knowledge is needed for human manipulator.On the contrary,same work can be done by direct teaching,which allows manipulator directly drag the robot to record the trajectory,this can extremely simplify the operation,enhance operation efficiency.This thesis intend to meet the requirements above,take advantage of a light-weight modular robot,and base on real-time Ethernet technology,to develop the co-operation function with human.In this thesis,the active compliance control based on impedance control has been chosen to realize the direct teaching function.By using force-free control algorithm,the gravity torque and friction torque have been compensated in each joint of the robot in torque control mode.Based on the structure analysis of a light-weight modular robot,D-H parameters are used to describe the kinematics model,matrix analysis method is applied to work out the kinematics description,it lays a theoretical foundation for the controlling of the robot later.The robot direct teaching has been realized by applying active compliant control,which is based on impedance control.The real-time gravity and friction torque compensation are realized base on force-free control strategy.The Simscape toolkit in Matlab is used to build up model of the servo motor,and the impedance control simulation model of single servo motor working in torque control mode has been built.The simulation proved that the controlling method and strategy proposed in this thesis is feasible,and also circumstantial proved that applying this single motor model to the direct teaching function in 6-DOF industrial robot is feasible,too.Based on real-time Ethernet technology EtherCAT,by setting up communication data objects,the close-loop torque control of servo motor has been realized.The impedance control,force-free control,and the direct teaching control algorithm have been written on TwinCAT PLC.The direct teaching function software module has been written on LabVIEW.Single axis impedance control,force-free control,and the direct teaching control experiments have proved the controlling method proposed in this thesis of great application value.