电火花加工用磁力驱动器的微定位控制

针对传统电火花加工中极间间隙的及时控制问题,提出一种具有高精度、响应快、宽频带、长行程的单自由度磁力驱动器,采用磁力驱动器作为电火花加工的局部执行机构,并设计了一种模糊PID控制方法在线实时修正PID控制参数,优化磁力驱动器控制系统. 首先, 分析了磁力驱动器装置的动力学模型,获得通入线圈电流与磁力驱动器动子位移之间的变换关系;其次, 根据磁力驱动器装置特点设计了常规PID控制器,并引入模糊控制对微定位控制性能进行优化;最后, 通过对磁力驱动器的微定位仿真和实验验证了控制器的控制效果. 仿真和实验结果表明:该磁力驱动器具有微米级的定位分辨率、大于50 Hz的宽频带和2 mm的定位行程,完全满足电火花加工微调要求. 

Micro-positioning Control of Magnetic Actuator for Electrical Discharge Machining

For timely controlling the gap between poles in electrical discharge machining (EDM), a single-degree-of-freedom magnetic actuator is designed with merits of high precision, fast response, wide frequency band and long stroke. As the local actuator in EDM, it is optimized by a fuzzy PID control method that modify the control parameters online and in real time. Firstly, the dynamic model of the magnetic actuator device is analyzed, and the transformation relationship is built between the coil current and the mover displacement in the magnetic actuator. Secondly, a conventional PID controller is designed according to the characteristics of the magnetic actuator device, and fuzzy control is introduced to optimize the performance of micro-positioning control. Finally, the controller performance is verified by the micro-positioning simulation and experiment on the magnetic actuator. Simulation and experimental results show that the magnetic actuator has a micron-level positioning resolution, a wide frequency band greater than 50 Hz, and a positioning stroke of 2 mm, which fully meets the fine-tuning requirements of EDM.