A Laser-Guided Solution to Manipulate Mobile Robot Arm Terminals Within a Large Workspace

Abstract

Globally accurate manipulation and localization of the terminal of a mobile robot arm within a large workspace has always been a bottleneck problem. In this article, a planar-laser-guided solution is proposed for this issue. The core of this solution is using three movable planar lasers to designate a unique reference point with orientation information within the workspace, and designing a sensor module mounted on the terminal of the robot arm with photoelectric position sensitive devices (PSDs) to measure the relative pose between the terminal and the reference point. Thus, the terminal of the robot can be guided by this relative pose to the target in a given orientation. According to this concept, a parameterized model of the moveable planar lasers and the poses of the PSDs, as well as an expression of their geometric relationship, were derived. The manipulation strategy of the robot arm was further investigated through the model, and an error compensation method to improve the manipulation accuracy was proposed. Finally, a reduced-scale prototype system, based on this solution, was built, on which tracking and positioning experiments of the robot arm were carried out to verify the feasibility of the solution. It has been shown that this laser-guided solution is not sensitive to the blockage (occlusion) of several laser transmitters, which could be an advantage for its application in future autonomous settings.