使用麦克斯韦力驱动的快速伺服刀具加工自由曲面,可以获得表面质量更优的加工效果.在快刀控制系统中引入适当的控制方式能够改善快刀的频响性能.本文针对麦克斯韦快刀,搭建包括软硬件在内的控制系统,硬件控制结构采用FPGA+DSP嵌入式控制架构,并加入自抗扰先进控制算法实现系统良好的抗干扰性能.为验证闭环控制系统性能,在自主搭建的精密位移测试平台进行系统位移分辨力和闭环带宽的测试,测试结果表明系统位移分辨力为5 nm,对频率108 Hz、峰峰值16μm正弦信号的跟踪误差为0.136μm,对频率540 Hz、峰峰值16μm正弦信号的跟踪误差为0.094μm.快刀系统行程50μm,闭环带宽4 kHz.线下仿真加工实验验证了快刀系统对常规面型的加工能力.
Fast tool servo ( FTS) system has high frequency response and flexible movement which can be used in machining freeform optical surfaces to obtain high cutting qualities. Appropriate control algorithms can improve frequency response of FTS systems. Both software and hardware control systems were de-signed according to Maxwell normal force FTS. Hardware control is made of FPGA + DSP embedded sys-tem while active disturbance rejection control (ADRC) algorithm was used in software control design to achieve high performance of disturbance rejection. In order to verify the performance of FTS closed-loop control system, the resolution and closed-loop bandwidth of the system were tested by using the self-de-veloped precision displacement platform. Results show that the system has a resolution of 5 nm, a stroke of 50μm, and 4 kHz closed-loop bandwidth, with 0. 136 μm error in tracking a 108 Hz sinusoid of 16 μm PV and 0. 094 μm error in tracking a 540 Hz sinusoid of 16 μm PV. Simulation of machining experi-ments verifies the machining ability on conventional surfaces.