非最小相位法向电磁应力驱动快速刀具伺服系统轨迹跟踪控制OA北大核心CSTPCD

Fast tool servo(FTS)diamond turning is effective for the ultra-precision manufacturing of complex-shaped optical surfaces.To further improve the control performance of a non-minimum phase normal-stressed electromagnetic FTS,a system dynamics inversion-based compensator is embedded in the main control-loop to improve the dynamics of the FTS.As for the improved system,a typical proportional-integral-derivative(PID)controller combining the feedforward compensator is introduced as the main controller.Furthermore,taking advantage of the internal model principle,a set of parallel resonant controllers are especially employed to ultra-precise track harmonic trajectories.Considering the non-minimum phase feature,a combination of the factorization and mirror pole placement method is conducted to obtain the stable inverse dynamics model of the system.The experimental results show that the inclusion of the dynamics inversion-based compensator can achieve a closed-loop bandwidth around 1 070 Hz(-3 dB).The tracking error for a 100 Hz sinusoid trajectory is less than±0.375%,and a stable closed-loop tracking of a 5 nm stair trajectory demonstrates the capability of the FTS control system for nano-cutting.