摘要
由于绳只能承受拉力,绳牵引并联机构必须采用冗余驱动。这种驱动冗余性导致无法平凡地求解各根绳的拉力值。而机构运动控制必须实时计算各根绳的拉力。为寻找绳拉力的优化解,必须研究绳拉力分布的优化问题。引入Verhoeven将绳拉力优化问题转换成一个在凸多面体上的非线性优化问题的研究方法,即将绳拉力的优化解表示成最低解和最高解的线性插值。由于优化解在某些情况下不连续,有必要将优化解做p-范数近似表达。探讨优化解的p-范数近似表达的实际算法,并对4根绳牵引的2自由度并联机构的最高解和最低解求解进行实例仿真。
Because wires can only sustain tension, actuation redundancy is necessary for wire-driven parallel manipulators, which makes wire tension can＇t be obtained in a trivial form. But real-time calculation of wire tension is necessary for motion control of the manipulators. To obtain the optimal tension solution, a new method proposed by Verhoeven is used, in which the optimal tension distribution problem is transformed into a non-linear optimization one on a convex polyhedra, i.e. the optimal solution is expressed by the linear combination of the lowest solution and the highest one. Owing to the discontinuity of the optimal solution in some cases, it is necessary to replace the infinity norm of the optimal solution by its p-norm approximately. Finally, the algorithm of the method is stated in detail and a case study to solve the lowest and highest solutions of a 2-DOF wire-driven parallel manipulators with 4 wires is given.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2005年第9期140-145,共6页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(50475099)
关键词
绳牵引并联机构
拉力分布
凸多面体
非线性优化
p-范数
Wire-driven parallel manipulators Tension distribution Convex polyhedra Non-linear optimization p-norm
