冗余铺丝机械手自运动流形分析及优化

针对传统位姿分离式铺丝机械手灵活性不足的特点,为了提高航空复合材料铺丝过程的灵活性和避障碍能力,提出一种位姿耦合式冗余铺丝机械手自运动流形的新算法。由于冗余铺丝机械手各关节之间的强耦合性增加了逆解的求解难度,该算法将冗余铺丝机械手的关节逆解分解为已知的Paden-Kahan旋量子问题以及由位置关节组成的特殊旋量子问题,并针对特殊旋量子问题进行求解得到冗余铺丝机械手全部逆解,这样相对于位姿分离式解法有效提高了冗余铺丝机械手逆解的求解效率以及求解直观性。由于冗余铺丝机械手的逆解呈现出流形的结构,所以根据冗余铺丝机械手自运动流形的多维特性,将冗余铺丝机械手的自运动流形分别映射到位置关节空间和姿态关节空间得到其三维仿真曲线。由于冗余铺丝机械手逆解流形中的优化流形在实际控制中更具应用价值,所以在铺丝机械手末端执行器沿芯模轨迹运动速度平稳的前提下为了使机械手各关节速度变化最小,提出以冗余铺丝机械手关节速度组成的约束泛函为目标得到相应的运动学优化流形,并为后续的最优控制奠定了基础。最后以某型号飞机S形进气道为例验证了所提方法的可行性。

Analysis and optimization for self-motion manifolds ofredundant fiber placement manipulator

Traditional position and posture separated fiber placement manipulator is less flexible.To improve the flexibility and obstacle avoidance capability of the manipulator for aerospace composite material placement,a new algorithm of self-motion manifolds is proposed for the position and posture coupled redundant fiber placement manipulator model.As the strong coupling between each joint of the redundant fiber placement manipulator can cause increased difficulty in obtaining inverse solutions,the inverse solution for the manipulator joint is decomposed into the known Paden-Kahan screw sub-problem and special screw sub-problem.Solution to the special screw sub-problem is obtained to get the whole inverse solution for the redundant fiber placement manipulator.The efficiency and intuitivity of the inverse solution for the manipulator is thus enhanced.As the inverse solutions for the redundant fiber placement manipulator presents a structure of manifolds,the self-motion manifolds of the redundant fiber placement manipulator are mapped to position joints space and posture joints space to get three-dimensional simulation curve based on the multi-dimensional characteristic of the self-motion manifolds of the redundant fiber placement manipulator.The optimized manifolds are more applicable than the whole general manifolds in the practical control,so the optimized manifolds are obtained by the objective function constituted by joint velocity of the redundant manipulator in order to enable the kinetic energy minimum and various joints velocity to change more smoothly and steadily while the end effector moves along the mandrel trajectory,providing foundation for subsequent optimum control.The method is verified by using the S-shaped inlet simulation.