Hexapod多自由度微激励系统的振动时域波形控制

Vibration Time Domain Waveform Control of Hexapod Multi-Degree-of-Freedom Micro Excitation System

Hexapod多自由度微激励系统常用于航天器有效载荷在轨微振动环境的模拟,但采用现有控制方法无法精确稳定跟踪低频正弦加速度,这是由于系统耦合度高、非线性在低频段较强,被控对象相位滞后过大造成的.针对此问题,基于传统离线迭代控制方法,提出一种复合超前校正、多倍频陷波滤波器的改进离线迭代控制方法.其中,离线迭代进行补偿控制,超前校正进一步补偿系统相位,多倍频陷波滤波器去除非线性干扰.跟踪低频定频正弦加速度的实验结果表明,对比传统离线迭代控制方法,改进方法收敛快、控制精度高;对比现有自适应正弦振动控制方法,改进方法将符合精度要求的加速度控制频带下限由14.5 Hz扩宽至8 Hz.实验结果验证了所提方法的有效性.

Hexapod multi-degree-of-freedom micro excitation system is mainly used to simulate on-orbit micro vibration environment of the spacecraft payload.However,the existing control method can’t track the low frequency given sinusoidal acceleration,in view of the system which was strongly coupled and seriously nonlinear in the low-frequency band,and the large phase lag of the controlled object.Aiming at this problem,an improved offline iteration control method combining lead compensation with the multiple frequency notch filter was proposed.The offline iteration performs compensation control,and the lead compensation further compensates the system phase,and the notch filter removes the nonlinear interference.The test results show that when tracking low-frequency sinusoidal acceleration,compared with the classical offline iteration control method,the improved method has fast convergence and high control precision,compared with the existing adaptive sinusoidal vibration control method,and widens the lower limit of the acceleration control band from 14.5 Hz to 8 Hz,accorded with the requirement of accuracy.The effectiveness of the proposed method can be validated by the experimental results.