无需示教即可校准激光视觉传感器时空偏差,提升焊接机器人精度。
Spatiotemporal Calibration for Laser Vision Sensor in Hand-eye System Based on Straight-line Constraint
- 利用S形轨迹扫描直线焊缝,通过普吕克坐标约束实现时空同步
- 实验验证在曲面焊缝上误差小于0.23mm,时间偏移与位姿参数同时优化
- 适合工业机器人场景,尤其适用于长期运行中参数漂移的系统
激光视觉传感器(LVS)是工业机器人在焊接应用中获取工件几何数据的关键感知模块。然而,相机通信延迟会导致图像捕获与机器人运动在时间上不同步,且手眼外参在长时间测量中可能发生漂移。为此,本文提出考虑相机时延的测量模型,并设计一种无需示教的时空校准方法,基于直线约束实现。该方法通过搭载LVS的机器人沿S形轨迹重复扫描直线角焊缝,无论机器人姿态如何变化,所有测量点均受直线约束,以普吕克坐标表示。进一步建立基于直线约束的非线性优化模型,采用莱文伯格-马夸尔特算法(LMA)联合优化时间偏移、手眼外参及直线参数。实验在曲面焊缝扫描任务中定量验证了该方法的可行性和高精度,结果表明最大误差低于0.23mm。代码、数据集与仿真报告已开源。
原文摘要 · Abstract (English)
Laser vision sensors (LVS) are critical perception modules for industrial robots, facilitating real-time acquisition of workpiece geometric data in welding applications. However, the camera communication delay will lead to a temporal desynchronization between captured images and the robot motions. Additionally, hand-eye extrinsic parameters may vary during prolonged measurement. To address these issues, we introduce a measurement model of LVS considering the effect of the camera's time-offset and propose a teaching-free spatiotemporal calibration method utilizing line constraints. This method involves a robot equipped with an LVS repeatedly scanning straight-line fillet welds using S-shaped trajectories. Regardless of the robot's orientation changes, all measured welding positions are constrained to a straight-line, represented by Plucker coordinates. Moreover, a nonlinear optimization model based on straight-line constraints is established. Subsequently, the Levenberg-Marquardt algorithm (LMA) is employed to optimize parameters, including time-offset, hand-eye extrinsic parameters, and straight-line parameters. The feasibility and accuracy of the proposed approach are quantitatively validated through experiments on curved weld scanning. We open-sourced the code, dataset, and simulation report at https://anonymous.4open.science/r/LVS_ST_CALIB-015F/README.md.
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