3SPS+1PS髋关节并联仿生试验系统工作空间优化

为使人工髋关节试验系统具有仿生模拟人体髋关节运动特性的能力，不但要使其能模拟髋关节各种运动形式，而且其运动输出空间应完全覆盖实际人体髋关节的运动范围，这也使得对其运动空间进行深入分析成为必要。针对作为髋关节并联仿生试验系统核心运动模块的3SPS+1PS并联机构，利用四元数法建立其逆/正解运动学模型，基于动平台三点构造法构建了3SPS+1PS并联机构的量纲统一速度Jacobian矩阵，分别比较了该矩阵条件数在不同运动空间及结构参数下的取值变化情况，得到条件数平均值与机构定、动平台上球副中心连线长度比值、球副许用转角及动平台中心位置高度等参数之间关系，优化了机构结构参数，进而得到了运动性能良好的运动空间区域。髋关节并联仿生试验系统运动空间的研究对其运动路径规划、动态特性分析及控制系统设计具有重要的意义。

Study on Workspace Optimization of 3SPS+1PS Parallel Hip Joint Simulator

In order to evaluate kinematics performance of an artificial hip joint, a novel hip joint simulator has been proposed, and the workspace analysis is necessary to ensure the capacity of simulating various activities and their motion ranges in daily human life. Comparing with the current simulators established by some serial manipulators, 3SPS+1PS parallel manipulator is designed as the key component of the hip joint simulator. Based on Quaternion method, the formulae for solving the inverse/forward kinematics equations are derived. The homogeneous velocity Jacobian matrix of 3SPS+1PS parallel manipulator has been established by constructing three related points on moving platform. Comparing the condition number variations in different workspace areas and structure parameters respectively, the structure parameters of the manipulator are optimized by analyzing the relationships among the mean values of the condition number and the design size ratio of base and moving platform, the allowable angles of spherical joints, the central height of moving platform are obtained. Furthermore, the suitable workspace to meet with the bionic essentiality of the hip joint has been obtained. The workspace optimization provided has great significance for trajectory planning, dynamic analysis and control design of the simulator.