Gap compensation control method for robotic electrochemical milling machining based on multi-physics field coupling

Industrial robot electrochemical milling has an important application prospect in efficient and precise machining of hard-to-cut part materials due to its advantages of high flexibility and strong sensing ability and is now becoming a hot spot in the research of new electrochemical machining technology. However, the weak stiffness and low accuracy problems of industrial robots themselves can create errors in the normal clearance in electrochemical milling machining. The inter-electrode gap (IEG) directly affects the process performance of electrochemical machining in terms of machining accuracy and surface quality. To reduce the effect of robot trajectory error on the interpolar gap, real-time compensation control of the machining gap is required. In this paper, we propose an industrial robot electrochemical milling normal motion error correction control system with a gap control strategy that is based on the coupled multi-physical field theory for averaging and solving the machining conductivity. The machining current is measured in real time, the current fluctuation is converted into a normal error compensation amount, and the end-effector accomplishes the error amount compensation for the machining gap. The response performance of the gap control system is simulated and analyzed, the experimental platform is designed and constructed, and finally, to verify the effectiveness of the machining gap control servo system, the plane workpiece machining experiments are carried out, and the experimental results surface that the method can effectively control the gap fluctuation in robotic electrochemical milling within a small range, and ultimately improve the machining accuracy and surface quality of the parts, which proves that the method can improve the machining accuracy of robotic electrochemical milling.