A Laser-based Dual-arm System for Precise Control of Collaborative Robots

TL;DR

This paper presents a laser-based dual-arm system that enhances the precision of collaborative robots in high-accuracy tasks by using laser sensing and point cloud registration to correct pose errors, validated through needle threading and USB insertion experiments.

Contribution

It introduces a laser-based sensing method combined with pose correction techniques to improve the precision of collaborative robots in complex assembly tasks.

Findings

Achieved 150μm precision in needle threading.

Successfully performed USB insertion with dual 7-axis robots.

Demonstrated effective pose error compensation in real tasks.

Abstract

Collaborative robots offer increased interaction capabilities at relatively low cost but in contrast to their industrial counterparts they inevitably lack precision. Moreover, in addition to the robots' own imperfect models, day-to-day operations entail various sources of errors that despite being small rapidly accumulate. This happens as tasks change and robots are re-programmed, often requiring time-consuming calibrations. These aspects strongly limit the application of collaborative robots in tasks demanding high precision (e.g. watch-making). We address this problem by relying on a dual-arm system with laser-based sensing to measure relative poses between objects of interest and compensate for pose errors coming from robot proprioception. Our approach leverages previous knowledge of object 3D models in combination with point cloud registration to efficiently extract relevant poses and compute corrective trajectories. This results in high-precision assembly behaviors. The approach is validated in a needle threading experiment, with a 150{\mu}m thread and a 300{\mu}m hole, and a USB insertion task using two 7-axis Panda robots.