考虑容错的平面二自由度过驱动机构力矩分配

针对过驱动机器人的故障驱动器数目不多于驱动冗余个数的情况,探讨如何进行故障前后的驱动力矩分配以保证机构具有容错能力.以平面二自由度过驱动并联机器人为研究对象,基于达朗伯原理和等效力方法建立其动力学模型,在此基础上分析了部分驱动器故障后机构的动力学方程,并进一步推导故障后容错力矩再分配方法.为减小故障后驱动力矩瞬时突变对机器人末端操作的影响,提出以故障前后的力矩差值平方和最小作为优化目标来进行过驱动机构力矩分配的方法.通过数据计算比较了采用传统方法和优化方法的各关节驱动力矩的突变量之和,结果表明所提出的优化力矩分配方法可以改善容错性能.

Force distribution of plane 2-DOF overactuated parallel manipulator with fault tolerance

In order to ensure the fault tolerant capacity of manipulator under scenario the failed actuators are no more than system redundancy,the driving force distribution before and after failure was researched.Based on the D'Alembert principle and the equivalent force theory,a plane 2-DOF(degree of freedom) overactuated parallel manipulator dynamics model was built.Then,dynamics equation of manipulator with partial failure was analyzed.And fault tolerant driving force redistributing method was further deduced.To reduce the impact of active force abrupt change to end effectors before and after failure,a driving force distributing method was brought forward.It took the minimum quadratic sum of driving force difference between overactuated and faulting system as optimization objective.With data analysis,the force change ranges of traditional method and minimum difference oriented fault tolerant method were compared.The result indicates this optimized force distribute method can obviously improve fault tolerant performance.