基于点触任务的可变形臂逆运动学求解

发布时间：2018-05-22 17:20

本文选题：可变形臂 + 旋量理论　；参考：《机器人》2017年04期

【摘要】：为了更好地适应家庭环境下的人机交互,设计了一款可根据任务需求相应调整连杆形状的四关节可变形操作臂.与传统刚性臂相比,可变形臂具有灵巧度高、成本低和本质安全等优势,但臂形的任意性也会给操作臂运动学逆解带来额外的困难.针对可变形臂的空间点触任务,本文通过引入"点触角"这一概念放松了末端执行器的姿态约束,从而使原本欠驱动的运动学逆解问题转化为了在满足点触位置约束下,以点触角最小为优化目标的冗余臂逆解优化问题.针对该问题的求解耗时和点触精度,在旋量模型的基础上分别提出了改进的序列二次规划法(SQP)和粒子群优化(PSO)与Paden-Kahan(PSO-PK)子问题混合算法.SQP方法直接在位置层面进行非线性最优化问题求解,实验结果显示该方法在臂形由特殊变为任意时求解耗时几乎不会增加,求解效率高,对可变形臂的在线实时控制具有一定意义;同时利用分层搜索法进行初值设定可以降低该算法陷入局部极值的概率.PSO-PK算法利用Paden-Kahan子问题法的解析逆解对粒子群优化算法进行降维,实验结果表明,该算法能够在保证点触位置无误差的情况下获得稳定的最小点触角,从而使点触性能得到提高.
[Abstract]:In order to better adapt to the human-computer interaction in the home environment, a four-joint deformable manipulator is designed, which can adjust the shape of the connecting rod according to the task requirements. Compared with the traditional rigid arm, the deformable arm has the advantages of high dexterity, low cost and essential safety, but the arbitrariness of the arm will bring additional difficulties to the inverse kinematics solution of the manipulator. In view of the space point contact task of deformable arm, the concept of "point antennae" is introduced to relax the attitude constraint of the terminal actuator, so that the inverse kinematics solution problem, which was originally underactuated, can be transformed to meet the point contact position constraint. Inverse solution of redundant arm with minimum antenna as optimization target. In view of the time consuming and point contact accuracy of solving the problem, Based on the spinor model, an improved sequential quadratic programming method (SQP) and particle swarm optimization (PSO) and Paden-Kahanen PSO-PKK (mixed algorithm) are proposed to solve the nonlinear optimization problem directly at the position level. The experimental results show that the time consuming of the method is almost no longer increased when the arm shape is changed from special to arbitrary, and the solution efficiency is high, which is significant for on-line real-time control of deformable arm. At the same time, using hierarchical search method to set the initial value can reduce the probability of the algorithm falling into local extremum. PSO-PK algorithm reduces the dimension of particle swarm optimization algorithm by using the analytical inverse solution of Paden-Kahan subproblem method. The algorithm can obtain stable minimum antennae without error of point contact position, so that the performance of point contact can be improved.
【作者单位】：南开大学机器人与信息自动化研究所;天津市智能机器人技术重点实验室;
【基金】：国家自然科学基金(61375087) 天津市应用基础与前沿技术研究计划重点项目(15JCZDJC31200)
【分类号】：TP242

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