Simulation-based optimization of CNC interpolator parameters for machining accuracy improvement

This paper proposes a new optimization algorithm of a computerized numerical controller (CNC) interpolator parameter using a simulation model to reduce trajectory error, which is the difference between the path of the part program and the actual trajectory. A tool path generation algorithm with a look-ahead of the CNC interpolator is proposed for high-precision machining. A feed drive model and control algorithm is modeled to describe the closed-loop dynamics of the CNC machine tool feed drive. The simulation model of machine tool is designed to estimate the trajectory error. To find the optimal parameter values of the CNC interpolator to improve machining accuracy, a simulation-based optimization method utilizing a genetic algorithm was used. A two-axis feed drive test rig was used to evaluate the estimation accuracy of the simulation model and investigate the effectiveness of the proposed method. Trajectory error was estimated using the simulation model, and compared with the experimental results, to evaluate the accuracy of estimation of the simulation model. The experimental results demonstrated that the trajectory error can be reduced without increasing the cycle time by applying the proposed optimization method.