Adaptive Backlash Compensation for CNC Machining Applications

The mechanical transmission employed inside the computer numerical control (CNC) machine electromechanical system usually has an inherent backlash. As a position-controlled system is commonly used for the electromechanical system, the backlash limits the performance of the motion control system due to its nonlinearity and discontinuity. This paper proposes an effective method to adaptively detect and compensate for the backlash effect in real time, in which the end-effect load position of the CNC machine is estimated and controlled by the position-controlled servo system, in order to eliminate the influence of backlash on the contour path performance. The simulation results obtained from the model of a realistic CNC machine show the successful elimination of the error between the reference and the end-effector position and a significant improvement in the control system performance.