重型模锻压机低速运行时极易出现爬行、抖动等现象,非线性摩擦力是该现象的主要成因.文中首先建立了d0MN等温模锻压机低速运行时的动态特性测试系统,进行了锻件的等温模锻试验,获得了压机在低于5μm/s的超低速度下运行时的加速度数据;然后基于Stribeck非线性摩擦模型,采用粒子群算法对摩擦力参数进行辨识并进行了验证;最后建立了重型模锻压机非线性摩擦的T.s模糊模型,并应用于摩擦前馈补偿控制系统.结果表明,Stribeck非线性摩擦模型可以较好地描述压机低速运行时的非线性摩擦,基于T.s模糊模型的摩擦前馈补偿能极大地提高非线性摩擦作用下系统的动态性能.
During the low-speed running of heavy die-forging press, creeping and jittering may occur mainly due to the existence of nonlinear friction. In this paper, first, a dynamic performance test system of a 40 MN die-forging press running at low speed was established. Next, some isothermal die-forging experiments were carried out to obtain the acceleration of the cross-beam of the press running at the speed of less than 5 txm/s. Then, based on the Stribeck nonlinear friction model, the friction parameters were identified and verified by using the particle swarm optimization algorithm. Finally, a T-S fuzzy model was constructed to describe the nonlinear friction of heavy die- forging press and was applied to a friction feedforward compensation control system. The results show that the Stri- beck model well describes the nonlinear friction of the die-forging press running at low speed and that the proposed feedforward compensation scheme based on the T-S fuzzy model greatly improves the dynamic performance of the system in the presence of nonlinear friction.