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为了使TMT三镜系统具有跟踪瞄准功能,同时可以校正由于重力引起的结构变形,设计一个大型的Stewart平台来完成三镜的Tilt调整。根据初始参数对并联机构进行了位置反解的计算,并分别对支腿轴向力和刚度进行了建模,最后使用了Matlab进行优化计算,得出一组最优解。根据所求出的最优解使用ANSYS建立了三镜系统的参数化模型,并与Matlab联合仿真,对三镜系统的各个工况进行了有限元模拟。仿真得到三镜各个工作位置时的支腿的伸长量、重力下的变形、第一阶模态值以及六根支腿内力。模拟结果显示,最终设计的Stewart平台支腿的最大变形量为0.813 mm,与优化前的模型相比下降了20%;第一阶模态最小值为16.7 Hz,与优化前的模型相比上升了18%;六根支腿的轴向力最大值为27 219 N,相比优化前下降了15.9%。
In order to make the TMT three-mirror system with tracking function, and can correct the structural deformation caused by gravity, we designed a large Stewart platform to complete the Tilt adjustment of three mirrors. According to the initial parameters, the parallel mechanism was calculated and the axial force and stiffness were modeled respectively. Finally, a set of optimal solutions were obtained by using Matlab. Based on the obtained optimal solution, a parametric model of the three-mirror system was established by using ANSYS and co-simulation with Matlab to simulate the various operating conditions of the three-mirror system. The simulation results show the elongation of the legs, the deformation under gravity, the first-order modal value and the six leg internal forces at each working position of the three mirrors. The simulation results show that the maximum deflection of the final designed Stewart platform leg is 0.813 mm, which is 20% lower than that of the model before optimization. The minimum value of the first mode is 16.7 Hz, which increases compared with the model before optimization Up to 18%. The maximum axial force of the six outriggers is 27 219 N, a drop of 15.9% compared with that before optimization.