基座运动对并联调整机构动力学性能的影响

以上海65 m射电望远镜六自由度并联调整机构为研究对象,研究基座运动对并联调整机构动力学性能的影响。首先阐述了并联调整机构的构型与位姿状态;然后分析了基座运动对动平台和驱动分支受力的影响,计算了基座运动引起的动平台和驱动分支惯性力和惯性力矩的变化,并分析计算了基座运动过程中引起的重力矢量方向的变化;进而采用具有高实时性特点的Kane方法分别建立了基座固定和基座运动两种情况下并联调整机构的动力学方程,最后分别采用Matlab和ADAMS软件仿真分析了基座运动对机构动力学性能的影响。仿真结果验证了所建动力学模型的正确性,同时也发现基座运动对此类机械系统动力学性能影响较为明显,在结构强度校核和控制系统参数设定时应加以考虑,以提高控制系统的准确性和结构强度的可靠性。

Influence of Base Motion on Dynamic Performance of Parallel Adjustment Mechanism

In order to research the influence of the base motion on the dynamic performance of the parallel mechanism, the six DOFs parallel adjustment mechanism of the Shanghai 65 meters radio telescope was selected as the study object, through theoretical calculation and simulation analysis to get the result of the research. Firstly, the configuration of the parallel adjustment mechanism was introduced, and six position parameters of the moving platform were selected as the generalized coordinates of the system to describe the position and the posture of the moving platform. Secondly, the force influence of the movement of the base on the moving platform and each driving branch was deduced, and the change of the direction of gravity vector caused by the movement of the base was analyzed, the Kane method was used to establish the dynamic equations of the parallel adjustment mechanism in the case of base fixing and moving. At last, the structure of the parallel adjustment mechanism and its physical parameters were set, the numerical and simulation analysis were carried out by Matlab and ADAMS software, respectively, the driving force variation curve and the contrast curve of each driving branch were obtained in two cases. The results of the two software simulations were the same, which verified the correctness of the dynamical model, through the contrast of the curves, it was also found that the influence of base motion on system dynamics was obvious, and it should be considered during the he structural strength check and control system parameters setting, so that the reliability of the control system and the reliability of the structural strength can be improved.