Research On The Lightwight Man-machine Cooperation Manipulator With Wireless Communication

The multi-axis robot system has an increasingly important role in replacing human beings from heavy and tedious tasks,such as packaging,transportation,handling,and other repetitive operations.The traditional manipulator has many internal cables and does not have force sensing function,resulting in the poor reliability,safety and maintainability.The traditional multi-axis robot is difficult to deal with the special tasks in space,battlefield,and home.This paper carried out the study of a light wireless human-machine collaborative robotic arm,which greatly reduces the cable lines and makes the manipulator have the ability of compliance control to complete the tasks together with human.Aiming at the requirements of complex human-machine collaborative task,the technical indexes of robotic manipulator are analyzed in detail.On this basis,the overall scheme of light wireless human-machine collaborative manipulator has been proposed.The manipulator joint uses the permanent magnet brushless DC motor as the power,the harmonic reducer as the transmission part,and designs the power-off brake to lock itself in the condition of power lost.The design integrates hall sensor,incremental magnetic encoder,absolute magnetic encoder and current sensor.So the position,velocity and current/torque of the joint can be measured.The manipulator's control system includes the central controller of the top layer,and the joint servo controller of the bottom.The kinematics and dynamics algorithms of the manipulator can be transplanted to the central controller and the joint servo controller can realize the position loop,velocity loop and current loop control.The joint servo controller uses the FPGA + ARM dual-processor architecture with redundant backup capability.The central controller communicate with the joint servo controller via ZIGBEE wireless mode,which greatly reduces the number of internal connections,improves the efficiency of assembly and debugging,and facilitates subsequent maintenance.The two types of modular joints are designed and assembled,and the joint servo controllers are integrated into the joints.The sampling process of the sensor,the debugging of the control algorithm and the wireless communication between the joints are completed.Furthermore,the test of joint performance index,including three-loop tracking experiment,joint stiffness and resistance experiment,load experiment,and the calibration for current and torque have been performed.The experiments show that the two kinds of modular joints reach the technical indexes.Finally,the seven modular joints,links and base are assembled.The central controller send angle command to seven joints through the ZIGBEE wireless network,and drive the movement of entire manipulator to complete the functional demonstration experiment.