主被动闭环融合调姿隔振平台动力学建模与模态分析

以载体设备对稳定工作环境的需求为背景,提出一种多维调姿隔振平台新构型,以实现大幅度位姿扰动的补偿和中高频振动的隔离。机构由3个分支组成,每个分支包含1个由主动调姿、被动隔振单元组成的闭环子链。借助于旋量代数及影响系数理论建立机构的运动学模型,得到动平台、开链分支、电动缸分支对广义坐标的一、二阶影响系数。建立机构主被动分离形式的动力学模型,并以此为基础对其进行模态分析。通过脉冲激励对原理样机进行模态实验,实验结果表明,固有频率的实验测定值与理论计算值接近,验证了理论模型的正确性。响应特性的实验结果表明原理样机能够对低频段的位姿扰动进行补偿,结合中高频的被动隔振,原理样机具备了较宽频带的调姿隔振能力。

Dynamic Modeling and Modal Analysis of Orientation Adjustment and Vibration Isolation Platform with Active-Passive Closed-loop Fusion

In order to realize the compensation of large-scale pose disturbance and the isolation of medium high frequency vibration, a configuration of multi-dimensional orientation adjustment and vibration isolation platform was proposed. The mechanism consisted of three branches, each of which contained a closed-loop chain composed of active orientation adjustment and passive vibration isolation unit. Referring to the screw algebra and the influence coefficient theory, the kinematics model of the mechanism was established, and the first and second order influence coefficient of the mobile platform, the open-chain branch and the electric cylinder branch on the generalized coordinates were obtained. A dynamic model of active-passive separation form of the mechanism was established. On this basis, the modal of the mechanism was analyzed. The modal experiment of the principle prototype was carried out by pulse excitation. The experimental results showed that the measured natural frequency was close to the theoretical calculation value, which verified the correctness of the theoretical model. The experimental results of response characteristics showed that the principle prototype can compensate the pose disturbance in the low frequency. Combined with the passive vibration isolation in the medium high frequency, the principle prototype had the ability to adjust the orientation and isolate the vibration in a wide frequency band.