An Approach for Task Priority Trajectory Planning of Redundant Robots
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摘要: 当机械臂末端沿期望轨迹运动时,若障碍物影响机械臂末端运动,则末端会与障碍物发生冲突,使其偏离期望运动轨迹。针对这一问题,提出了一种任务优先级轨迹规划方法,使机械臂末端避障后能够继续跟踪期望轨迹。当机械臂末端运动轨迹中含有障碍物时,赋予避障运动作为优先控制,通过计算末端位置增量使机械臂末端产生逃离速度,进而避开障碍物;反之,赋予轨迹跟踪作为优先控制,通过对机械臂期望轨迹与实际位置进行误差控制,达到提高末端轨迹跟踪精度的目的。最后,对冗余机器人进行了仿真及试验验证。结果表明,当障碍物与机械臂末端运动轨迹发生冲突时,基于任务优先级的轨迹规划方法可以使机械臂末端有效地避开障碍物,同时,末端避障后机械臂仍能跟踪到期望轨迹运动。Abstract: When the arm end of the manipulator moves along the desired trajectory, if some obstacles affect movement of the end, it makes arm deviating from the expected trajectory, even the end maybe be clashed with obstacles. Aiming at this problem, a new method of trajectory planning task priority is put forward in this paper, in which the end of the manipulator can avoid the obstacle and continue to track the desired trajectory. So as to realize the priority transformation between the obstacle avoidance motion and trajectory tracking, when the end of the manipulator trajectory appears obstacles, give priority control to obstacle avoidance movement. Through calculating the terminal position increment makes the arm end effecter produces escape velocity, thus avoiding obstacles; Conversely, giving trajectory tracking as priority control. Based on the desired trajectory and the actual manipulator position error control, which achieve the goal of improving the terminal trajectory tracking precision. Finally, simulation and test verification have been done for the redundant robots. Results show that when the barrier and mechanical arm terminal trajectory are conflict, the trajectory planning method based on task priority can make the end of manipulator effectively avoiding obstacles. At the same time, the arm can still track the desired trajectory after obstacle avoidance.
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Key words:
- redundant robot /
- task priority /
- obstacle avoidance /
- trajectory tracking
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