In order to investigate the influence of spatial cylindrical joints with clearances on system performances,all possible contact modes of a typical spatial cylindrical clearance joint were analyzed.Aiming at the spatial cylindrical joints with clearances in the axial and radial directions,the geometry and kinematics of complicated contact modes were analyzed.An improved method for computing potential contact points was proposed.The normal contact impact force model and the tangential friction force model were set up.Then,the multi-body dynamic equation was given with consideration of the normal contact impact force and the tangential friction force.Finally,a spatial double pendulum with joint clearance was taken as an example and the results were compared with those by using the ideal model.The results show that the kinematic accuracy and dynamic performance of the system were affected greatly,because of the existing clearances in the axial and radial directions,and different clearance sizes can change the kinematic accuracy of the system.The method and the results provide a theoretical basis for the design and improvement of the mechanical structures.%为了研究空间圆柱铰间隙对系统性能的影响,针对典型的空间圆柱间隙铰结构,分析了其所有可能出现的接触模式.针对空间圆柱铰轴向和径向都存在间隙的情况,对复杂的接触模式进行了几何和运动学分析,提出一种改进的计算潜在接触点位置的方法,建立了接触碰撞力模型,将其带入多体系统动力学方程.对空间双摆进行了理想模型和间隙模型的对比分析.结果表明,由于轴向和径向间隙的存在,系统的运动学精度和动力学性能都受到了很大的影响,间隙大小的变化也会改变系统的运动学到位精度.空间圆柱间隙铰的建模方法和结果为机械结构的设计和改进提供了理论依据.
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