Research On The Control System Of Human-like Double-arm Care Robot

In this paper,a new method of multi-degree-of-freedom coupling control based on the design of PLC control program and electronic gear function of Beck Hoff TwinCAT3 is proposed,and a control system of humanoid double-arm nursing robot is developed.According to the dual robotic arm and lumbar joint structure design and movement law of the nursing robot,the mathematical model of the dual-arm nursing robot is established by the improved DH modeling method,and the kinematics analysis is carried out to establish the relevant joint variable transformation matrix.The shoulder joints of the two arms are mainly studied.The relationship between the elbow joint and the wrist joint was established.The mathematical model was established and the inverse kinematics analysis was performed.The inverse kinematics solution was performed according to the set of the two-arm end pose matrix to obtain the torsion angle of the six joints of the left and right arms.Based on the EtherCAT bus The communication protocol completes the hardware connection and communication between multiple servo drives,motors and controllers;after using the host computer software to complete the IO port physical axis configuration and NC axis interface control debugging,write the PLC program to realize the software motion control;write the PLC motion control code,Calling enable,relative position setting,electronic gear and other functional blocks to realize the multi-joint axis coupling linkage of the nursing robot;among them,the electronic gear function block is mainly designed,and the main and secondary axes are designed according to the torsion angle of the six arms of the two arms calculated by inverse kinematics analysis.Coupling factor with electronic gear to achieve the joint axis the twist angle operation,the nursing robot arms to reach the set position.Finally,using the Scope View oscilloscope monitoring function of the host computer software to carry out the experimental verification of the no-load and the escaping operation of the nursing robot,the actual running speed and position change waveform diagram of the joint axes of the two arms are obtained,and the actual running speed and program setting of each joint axis are calculated.The fixed speed error value does not exceed 5%,which is a reasonable error range;the actual running speed and position change of the joint arms of the two arms are consistent with the design of the PLC program and the electronic gear algorithm,so the arms of the nursing robot can be analyzed according to inverse kinematics.The solved torsion angle run reaches the set end position to achieve the desired care action.The experimental results are in line with the expected design,which verifies the correctness,feasibility and stability of the new software design method.This PLC control electronic gear coupling control method makes the robot control more simple and accurate,and has high fault tolerance and easy modification.It is innovative in the control system of multi-axis robots.