【摘要】 以一种两转动一移动非对称2UPS-UP并联机构为研究对象,对其进行了性能分析和尺度参数多目标优化。机构自由度由恰约束支链UP确定,即机构可实现绕该支链U副中心的两转动运动和沿P副的移动运动。给出正逆向位置符号解,且正逆解具有部分运动解耦特性,有利于后续误差分析、轨迹规划与控制。应用矢量法推导出速度表达式,根据速度Jacobian矩阵分析了机构奇异位形。以旋量代数为工具,给出了机构运动和力传递性能评价指标。在机构性能评价和工作空间分析的基础上,建立了机构尺度参数昂贵约束多目标优化模型,并采用多目标进化算法求解该问题,得到多组Pareto最优解。更多还原

【Abstract】 Taking an asymmetry 2UPS-UP parallel mechanism with two rotational and one translational degrees of freedom as the research object,the performance analysis and multi-objective optimization of dimensional parameters for the mechanism are presented.The degrees of freedom of the mechanism are determined by the suitable constraint branch UP,so the mechanism can perform two rotational motions around the center of U pair and one translational motion along the P pair of the branch.The symbolic solutions to the forward and inverse displacement analysis are derived.This mechanism with the partial motion-decoupling characteristics is of great benefit to subsequent research such as error analysis,motion trajectory planning,and control.This study proposes the analytic expressions of velocity analysis by means of the vector method.With the aid of the singularity of speed Jacobian matrix,the possible singular configurations of the mechanism are analyzed.Screw algebra is used as a mathematic tool to give the evaluation indices for motion and force transmission performances of the mechanism.Based on the performance evaluation and workspace analysis,an expensive constrained optimization model is constructed to formulate the design problem of dimensional parameters.Furthermore,a multi-objective evolutionary algorithm is employed to solve this problem,and multiple Pareto optimal solutions are obtained.更多还原