多关节人体上肢运动的优化轨迹预测

研究了手端无约束条件下,多关节人体上肢点到点运动优化轨迹的预测. 首先建立了多关节上肢平面运动的动力学模型,根据最小功准则提出优化目标函数,将上肢点到点运动的优化轨迹求解问题转化为两点边值问题,设计了寻优的迭代算法,求得了上肢运动的优化轨迹与相应的速度变化曲线. 仿真结果表明: 平衡点位置或关节力矩平滑地变化,避免了肢体出现急加速-急减速的运动形式,减少了肢体运动时的能量消耗;手端的运动轨迹为近似直线,速度为单峰的钟形曲线,这与上肢优化运动的特征相吻合,也表明最小功准则可以有效预测多关节上肢运动的优化轨迹. 

CALCULATION FOR OPTIMIZED MOVEMENT TRAJECTORIES OF HUMAN MULTI-JOINT ARM

The calculation for optimized trajectories ofunrestricted multi-joint human arm in point-to-point reaching movement wasinvestigated. The planar motion equations of multi-joint arm were introducedat first, then the optimal criterion was constructed according to minimaleffort criterion, and the human arm point-to-point reaching movement wastreated as a two-point boundary value problem, finally an iterativealgorithm was presented to find the optimized arm trajectories and velocityprofile. The simulation results show that the equilibrium point or jointtorque varies smoothly,which avoids the large fluctuation of arm speed andreduces energy consumption when arm moves; the movement trajectory of handis roughly a straight line, and the corresponding velocity profile issingle-peaked and bell-shaped, which is in good agreement with the kinematicdata from the arm movement. Therefore the minimal effort criterion is alsoeffective for calculating the optimal movement trajectories of multi-jointarm.