提出一种能实现空间两移动和两转动的新型4-SPS/PPU四自由度并联机构模型,其中SPS支链为驱动支链,PPU为恰约束从动支链.采用螺旋理论计算了4-SPS/PPU并联机构的自由度.讨论了该机构的位置反解与正解,通过对位置方程求一阶微分,导出该机构的Jacobian矩阵,并分析了其加速度性能,给出了该机构Hessian矩阵的求解方法.根据运动Jacobian矩阵推导出该机构的条件数,通过数值分析验证了结构参数对该机构灵巧度的影响.为该机构的构型设计提供了理论依据.%Spatial parallel mechanism of a novel 4-SPS/PPU which can perform two-dimensional translations and two-dimensional rotations is presented.The SPS-limp is regarded as the driver and PPU-limp is regarded as the driven machine in the 4-SPS/PPU parallel mechanism.The degree of freedom of the mechanism is calculated based on the screw theory.The forward and reverse solutions of position are discussed.The Jacobian matrix of the mechanism is exported via the first order difference of the position equations.Acceleration performance of the mechanism is analyzed,and the solution of the Hessian matrix is presented.The conditional number of the mechanism is derived according to the Jacobian matrix.The influence of the strutural parameters on the dexterity of the mechanism is checked by the numerical analysis.The theoretical basis is provided for the configuration design of the mechanism.
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