以三平移一转动(3T1R)并联机构为研究目标,提出一种具有解析式位置正解的3T1R并联机构,计算自由度并证明机构能实现空间三维平移且沿着z轴转动.建立运动学位置方程并推导出机构的位置正解和逆解解析式,同时根据算例分析、验证其解析式的正确性,选择蒙特卡洛法随机模拟法分析机构的工作空间性能.另外,根据运动学方程推导得到正解奇异和逆解奇异的存在条件.根据NSGA-II算法得到了Pareto优化前沿曲线.结果表明:机构具有较大、对称、光滑的工作空间,在工作空间内转动性能较好.
A 3T1R parallel mechanism with analytical forward position solution is proposed.The research objective three translational and one rotational parallel mechanism is taken as object.The freedom is calculated and verified that the mechanism can realize three-dimensional translation and rotation along the z-axis.The kinematics posi-tion equation is established,and the analytical formulas of the forward and inverse position solutions of the mecha-nism are derived.At the same time,the correctness of the analytical formula is verified according to the analysis of an example.The Monte Carlo method is selected to analyze the performance indexes,such as reachable work-space.In addition,and the existence conditions of the singularity of the positive solution and the singularity of the inverse solution are deduced.It analyzes the influence trend of structural parameters and workspace volume.Final-ly,according to the established mathematical model of workspace maximization,the optimal design parameter size is selected by genetic algorithm.The results show that the mechanism has a large,symmetrical and smooth work-space.The optimized results lay a theoretical foundation for the application design of the mechanism.