大型液压机驱动系统摩擦补偿控制
The Friction Compensation for Giant Hydraulic Press

为提高大型液压机驱动系统控制精度，提出了基于改进型LuGre摩擦模型的补偿控制方法。建立了液压机驱动系统的动力学模型，通过改进型LuGre模型来描述液压机的综合摩擦特性。分别设计了PID控制器、2自由度PID控制器以及模糊自适应控制器，通过仿真实验验证了补偿方案的有效性，并对比分析了3种补偿控制方案的效果。仿真结果表明：采用模糊自适应补偿控制方案效果最优，2自由度PID补偿控制方案次之，常规PID补偿效果最差。当以正弦运动作为驱动系统的输入信号时，采用模糊控制补偿方案的速度跟踪均方误差（Mean Square Error， MSE）能从PID补偿方案的5.771×10-3减小至5.903×10-4。采用模糊自适应补偿方案能有效地抑制摩擦对液压机驱动系统低速性能的不利影响，可显著提高其动态跟踪性能。
In order to improve the precision of the drive system for giant hydraulic press, the friction compensation schemes based on the modified LuGre model are proposed. The dynamic model of the drive system is established, and the friction characteristics of hydraulic press are described based on the modified LuGre model. The PID controller, two-DOF (degree-of-freedom) PID controller and the fuzzy adaptive controller are designed respectively; thereby the validity of the compensation schemes is validated via control system analysis. The simulation results show that the fuzzy control compensation scheme occupies the first place, the two-DOF strategy comes second and the conventional PID methodology is the worst. Adopting the fuzzy adaptive controller based on the compensation strategy, the mean square tracking error (MSE) is decreased to 5.903×10-4, comparing with that of traditional PID control method, 5.771×10-3. Hence, the presented compensation scheme can restraint the negative influence of friction and promote the dynamic performance of the drive system evidently