正交并联多自由度加载试验系统研究

Loading test system of orthogonal parallel multi-degree-of-freedom

针对传统的单轴加载系统无法实现对接机构组合体疲劳试验所需的多维广义力加载问题,结合六自由度并联机构的特点,提出了一种基于正交并联机构的多轴加载试验系统,并对系统结构组成、动力学关系以及系统整体控制策略等方面进行了研究。利用Newton-Euler法对加载系统静态加载和动态加载进行了动力学建模,并以此建立了广义力反解Simulink模型,实现了广义力到作动器期望输出力的解算。将解算得到的结果输入各作动器驱动力控制系统中,利用PID控制及动压反馈使各作动器响应特性达到了要求。为避免六维力传感器带来的高昂成本,系统采用基于作动器输出力闭环的整体控制方案进行了动态加载试验。试验结果表明,系统加载误差小于1%,能够实现对组合体的精确加载,为其疲劳和可靠性测试提供了精准的试验数据。

Aiming at the traditional loading system lacked the ability to provide muti-axis forces and torques which was needed in the fatigue test of space docking mechanism,an orthogonal six degrees of freedom（ 6-DOF） parallel loading system was presented,and the configuration,dynamics and control strategy of the system was studied. The dynamics of static loading and dynamic loading was built using NewtonEular method. Based on it,the Simulink model about inverse solution of dynamics was built,which could transform generalized force into actuator force. Then the PID control combined with dynamic pressure feedback was used to achieve the control requirements. In order to avoid the use of 6-DOF force sensor,which would bring high costs,the control strategy of the system was built based on actuator force closed-loop.Experimental results indicate that the system loading error is less than 1%,which can provide an accurate data for the fatigue and reliability test of the mechanism.