摘要
针对冗余度机械臂的动态避障规划问题提出一种新颖的混合指标避障算法。考虑到移动障碍物运动的随机性,在障碍物位于机械臂构形之内时采用最短距离指标作为避障指标,并利用梯度投影法进行规划。而在障碍物位于机械臂构形之外最短距离指标失效时采用避障面积指标进行替代。在整个避障过程中两种指标的混合使用实现机械臂构形微调与粗调的相结合,提高整体的避障效果。另外,在线动态调整放大系数以控制零空间解与最小范数解的2范数比值恒定,避免可能出现的关节速度超限现象。以平面3R2P冗余度机械臂为例具体阐述这种算法。单独指标规划和混合指标规划的对比仿真试验表明,提出的混合指标避障算法在避障效果方面具有优越性和有效性,并通过实物试验证明该算法可以较好地满足系统的实时性要求,具有一定的通用性。
A new hybrid index dynamic obstacle avoidance algorithm for redundant manipulator is proposed.Considering the randomness of the moving obstacle,the shortest distance index is used as the index of the obstacle avoidance planning based on gradient projection method when the moving obstacle is inside the configuration of the manipulator.When the moving obstacle is outside the configuration,the obstacle avoidance area index is used to substitute for the invalid shortest distance index.Through using the hybrid index,the combination of fine adjustment and coarse adjustment for the configuration of the manipulator is realized.And the effect of the whole obstacle avoidance is improved.In addition,the problem of exceeding the joint velocity limit can be solved by the on-line adjustment of the magnification factor,so as to keep a constant ratio between null-space-solution and minimum-norm-solution.The algorithm is illustrated by a planar 3R2P redundant manipulator.The simulations of comparison between single index planning and hybrid index planning show superiority and effectiveness of the latter.And the real object experiments prove the real-time performance and universality of the algorithm.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2010年第19期30-37,共8页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(50775002)
关键词
冗余度机械臂
动态避障规划
混合指标
放大系数
Redundant manipulator Dynamic obstacle avoidance planning Hybrid index Magnification factor
