A Fast Solution to the Dual Arm Robotic Sequencing Problem

Abstract

Robotics applications such as spot-welding, spray-painting, drilling, and objects handling, require the robot to visit successively multiple targets. The robot travel time among targets is a significant component of the overall execution time. This travel time is in turn greatly affected by the visiting order and by the robot configurations used to reach each target. It is crucial to optimize these elements during the motion planning stage, a problem known in the literature as the Robotic Task Sequencing Problem (RTSP). This problem has been studied by the robotics community but only for single arm manipulators. Our contribution in this paper is to extend an existing RTSP algorithm to the dual arm case. The key to our approach is to exploit the classical distinction between task-space and configuration-space, which, surprisingly, has been so far overlooked in the RTSP literature. We show experimentally that our method finds high-quality motion sequences and requires a reduced amount of computation time, making it ideal for real-world applications. For a toy-example of a pick-and-place task, the proposed dual-arm RoboTSP takes less than 20 s to solve the task sequencing problem and compute the collision-free trajectories.