一种新型并联动力头的前馈控制策略与实验

为满足高速并联动力头在高速加工时的动态控制精度要求,研究了基于Turbo PMAC运动控制器的动力学控制方法,提出一种基本伺服算法与动力学前馈补偿相结合的控制策略.通过二次插补获得粗插补信息,再根据虚功原理建立力矩补偿模型.利用Turbo PMAC的力矩偏置设置功能,将补偿力矩按照粗插补周期发送给基本伺服系统,进而减少偏差反馈所需的控制能量.在新型三坐标并联动力头上进行了不同工况的实验,证明该控制策略易于实现,通用性强,可大幅减少高速运动下的跟随误差和力矩波动,明显改善系统的动态特性,提高运动精度.

Feedforward Control Strategy and Experiment on a Novel Parallel Spindle

The dynamic control method based on the Turbo PMAC was studied for meeting the dynamic precision requirement during high speed machining with parallel spindles.A dynamic feedforward compensation strategy integrated with basic servo algorithm was proposed.Based on the virtual work principle,the dynamic torque compensation model was formulated according to the coarse interpolation information obtained through two-step interpolation method.By setting the torque offset defined in Turbo PMAC,the compensated torque was sent to the basic servo algorithm in coarse interpolation cycle period in order to reduce the burden on error feedback control.The experiments were implemented on a new type 3-DOF parallel spindle under different machining situations.Results show that the control strategy is practical and generic,and the following error of drive motor and the amplitude of vibration of the drive torque are dramatically reduced.The dynamic character of the equipment is then well improved,and the kinematic accuracy is enhanced.