基于压电作动器的空间单轴主动隔振研究

Spaceborne Single Axis Active Vibration Isolation Based on Piezoelectric Actuator

对六自由度空间Stewart隔振平台中基于压电作动器的单轴主动隔振进行了研究。提出了三类标准以衡量隔振性能,其中:第Ⅰ类为载荷端与扰动端同量纲振动量比;第Ⅱ类为隔振后载荷端的受力与隔振前固连时载荷受力比;第Ⅲ类为隔振前后振动量的衰减状况。给出了压电作动器的基本方程,并根据实际进行了数值修正。建立了线性化的压电作动器单轴隔振系统,采用作动器的运动总与扰动端振动分量互补的主动隔振策略。讨论了速度反馈控制、力反馈控制与代数环引入,以及质量对隔振性能的影响。提出了隔振方向和隔振代价的概念。仿真结果表明速度反馈和力反馈均能获得较好的隔振效果。理论分析了隔振方向对隔振性能和隔振代价的影响。研究为空间Stewart隔振平台设计提供了理论支持。

The single axis active vibration isolation on the spaceborn Stewart vibration isolation platform with six degree of freedom was studied based on piezoelectric actuator in this paper.Three kinds of measurement standards were put to evaluate isolation performance.Among those,the first one was ratio of vibration quantities at the payload end to disturbance end with the same dimension,and the second one was ratio of force at the payload end after isolation to force while being mounted before isolation,as well as the third one was attenuation of vibration quantity before and after isolation.The general equation of piezoelectric actuator was given and was modified according to the real situation.The linearization single axis vibration isolation system based on piezoelectric actuator was established.The active vibration isolation strategy was adopted in which the actuator motion was always matched the vibration at disturbance end.The velocity feedback control,force feedback control and algebraic loop leading in,and effects of mass on the isolation performance were discussed.The concept of reduction direction and reduction cost were put forward.The simulation results showed that good isolation performance would be obtained through velocity feedback and force feedback.The influence of reduction direction on both reduction performance and reduction cost was analyzed theoretically.The study provides some reference for designing spaceborne Stewart vibration isolation platform.