数控机床切削力负载模拟器的显式力控制算法设计

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

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。

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 ex- periments is conducted on a stationary and a moving spindle, respectively, to validate the feasibility of the proposed control system.