大功率五坐标机床A轴的新型控制算法设计

Novel Control Algorithm Design for A-Axis of High-Power Five-Axis Machine Tools

针对齿隙和非线性摩擦对A轴控制精度的影响,设计了增益自调节模糊控制器,通过引入基于连续指数函数的增益自调节策略,消除了传统模糊控制中增益切换引起的控制律突变.虽然增益自调节模糊控制可以实现良好的动态响应和较小的稳态误差,但其需要二维模糊控制规则表来计算控制律,这在一定程度上影响了控制系统的动态响应速度.因此,设计了增益自调节模糊滑模控制器,通过采用模糊控制来逼近滑模等效控制律中的非线性函数项,消除了传统滑模控制的抖振现象.实验结果表明,本文所设计的两种控制算法均能实现较快的零超调动态响应及较高的稳态精度,能有效提高整体叶盘型面的加工精度和表面一致性,并显著降低叶片表面粗糙度.

According to the influence of backlash and nonlinear friction on the control precision of the A- axis, the fuzzy controller （FC） with gain auto-tuning was proposed. Mutation of the control law caused by the gain switching in the traditional fuzzy control was eliminated by introducing the gain auto-tuning strat- egy based on the continuous exponential function. Although the FC with gain auto-tuning can achieve good dynamic response and smaller steady state error, it needs the two dimensional fuzzy control rules ta- ble to calculate the control law. To a certain extent, this control algorithm limits the dynamic response speed of the control system. Therefore, the fuzzy sliding mode controller （FSMC） with gain auto-tuning was proposed, and the chattering phenomenon in the traditional FSMC was eliminated by employing the FC to approximate the nonlinear function item in the equivalent control law. Experimental results show that both control algorithms can achieve higher steady state precision and faster dynamic response with ze- ro overshoot. They can also improve blisk machining precision and surface consistency, and significantly reduce surface roughness.