Spatiotemporal Calibration for Laser Vision Sensor in Hand-eye System Based on Straight-line Constraint
The paper was submitted to IEEE TIE. We developed a laser vision sensor, which can be used for 3D construction, welding, etc. This research proposed a teaching-free quick spatiotemporal calibration method, only relying on a common straight object.
This repository contains our experimental data, including measured robot end-effector's pose and images. Videos of the calibration data collection process are also available at: https://drive.google.com/drive/folders/1Pr17LXiu3qDicMFDcD92kjfhX2Ftdzxk?usp=share_link
If you have any question, feel free to contact me: peiwen1.yang@connect.polyu.hk
The laser vision sensor (LVS), acting as the “eye” of an industrial robot, allows it to perceive geometric information in its environment. However, the camera communication delay will lead to a time mismatch between captured images and the robot’s motions, and hand-eye extrinsic parameters may vary during the manufacturing process. To address these issues, we propose a measurement model of LVS considering the effect of camera’s time-offset and a teaching-free spatiotemporal calibration method utilizing line constraints. This method is achieved by making a robot equipped with an LVS repeatedly scan along straight-line fillet welds with S-shaped trajectories. No matter how the robot’s orientation changes, all measured welding positions are constrained within a straight-line, which is represented using pucker coordinates. Moreover, a nonlinear optimization model based on a straight-line constraint is established. Subsequently, the Levenberg-Marquardt (LM) algorithm is employed to solve the parameters, including time-offset, hand-eye extrinsic parameters, and straight-line parameters. The feasibility and accuracy of this approach are validated through simulation and a curve weld scanning experiment. We open-source the code at https://github.com/RoboticsPolyu/LVS_ST_CALIB.
https://drive.google.com/drive/folders/1Pr17LXiu3qDicMFDcD92kjfhX2Ftdzxk?usp=share_link
The spatiotemporal calibration program is as follows:
spatiotemporal_calibration_lvs
This repo also provides functions, such as the laser camera calibration, fillet weld feature detector, and spatiotemproal calibration simulation.
Enjoy !