数控机床切削力负载模拟器的显式力控制算法设计

为了对数控机床进行可靠性试验,设计了一种基于3P-(4S)并联机构的负载模拟器。基于PI反馈控制的显式力控制算法,并引入了模糊控制器,提高系统对不同加载误差的适应性。在控制系统中引入了力前馈控制器,提高控制系统的动态性能,减少实际加载力的滞后。同时,由于加载目标即机床主轴的进给运动轨迹未知,因此引入了主轴位置预测前馈以进行运动补偿,减少主轴运动所带来的干扰。最后设计并实施了静态与动态负载模拟试验,验证了所提控制算法的有效性。

Explicit Force Control of a Cutting-Force Simulator for Numerical Control Machine Tools

For reliability tests of machine tools,a load simulator based on a 3P-(4S) parallel mechanism is proposed.An explicit force control system is designed based on a proportional-integral (PI) controller.A fuzzy logic is introduced to adapt various following errors of output forces.A force feedforward is integrated to the system to develop its dynamic performance and decrease the hysteresis of the output forces.Meanwhile,a position feedforward that predicted the position of the spindle is designed to eliminate the disturbance caused by the unknown feeding motions of the spindle.Loading experiments is conducted on a stationary and a moving spindle,respectively,to validate the feasibility of the proposed control system.