3SPS+1PS并联仿生试验机误差建模与仿真

3SPS+1PS并联髋关节仿生试验机能否模拟人工髋关节的理想试验状态是正确评价关节材料特性的关键,因此,对此并联试验机整机误差建模及仿真成为必须。首先运用四元数法对其动平台位姿进行描述,建立了基于矩阵全微分理论的整机误差分析模型。通过计算机仿真,讨论了机构参数对位姿精度的影响,同时计算了单一结构或驱动参数误差变化时,输出位姿的变化趋势。由仿真结果知,输出误差中X轴误差和参数q误差较大,Z轴误差与参数n误差几乎为零。最后,对设计过程中机构参数的合理选取提出建议,为实际误差的补偿与控制提供了一定的理论基础。

Error Model and Simulation of 3SPS+1PS Parallel Bionic Test Mechanism

Whether 3SPS+1PS parallel bionic test mechanism can simulate the ideal experimental state of hip is the key to evaluate the material property of joint.So the error model and simulation of the mechanism is necessary.Using the quaternion method,the pose of moving platform is described.The error model of this mechanism based on the complete differential coefficient theory is established.Through numerical simulation,the influence of the structure and drive parameters on the position and stance accuracy is analyzed.The trends of output parameters are calculated when single input parameter varies.The results show that the error of X-axis and the error of quaternion parameter q are lager,while the error of Z-axis and the error of quaternion parameter n are almost zero.Finally,the suggestion of structure and drive parameters reasonably selection is proposed,a theoretical base for compensation and control of the errors in practice is provided.