双向二维快速伺服刀架的前馈控制研究

Feedforward Control of Bidirectional 2-DOF Fast Tool Servo

以压电陶瓷驱动器作为动力输入的快速伺服刀架具有输出力大和高频率响应的优点。压电陶瓷驱动器固有的迟滞现象严重影响了快速伺服刀架的输出定位精度。为解决此问题,通过引入归一化Bouc-Wen模型建立前馈控制补偿器,归一化Bouc-Wen模型解决了经典Bouc-Wen模型中存在的参数冗余问题。获得模型参数后,基于其逆模型搭建了前馈补偿器,并在搭建的实验平台上进行了单/双自由度轨迹跟踪性能测试。实验结果表明,对于等幅正弦波信号,经前馈控制环节补偿下快速伺服刀架的最大轨迹跟踪误差为1.18%,最大轨迹跟踪偏差为2.61%,证明该文所提出的前馈控制补偿器能提高快速伺服刀架的定位精度。

The fast servo tool post with piezoelectric ceramic driver as the power input owns the obvious advantages of large output force and high frequency response.However,the inherent hysteresis of the piezoelectric ceramic driver seriously affects the output positioning accuracy of the fast servo tool post.In order to solve this problem,a feedforward control compensator is established by introducing a normalized Bouc-Wen model.The normalized Bouc-Wen model solves the problem of parameter redundancy in the classic Bouc-Wen model.After obtaining the model parameters,a feedforward compensator is built based on its inverse model.The single/double degree of freedom trajectory tracking performance test is carried out on the built test platform.The test results show that for a constant amplitude sine wave voltage signal,the maximum trajectory tracking error under the compensation of the feedforward control link is 1.18%,and the maximum trajectory tracking deviation is 2.61%.It proves that the proposed feedforward control compensator can significantly improve the positioning accuracy of the fast servo tool.