Particle filter framework for 6D seam tracking under large external forces using 2D laser sensors

Carlson, Fredrik Bagge; Karlsson, Martin; Robertsson, Anders; Johansson, Rolf

doi:10.1109/iros.2016.7759549

Cited by 1 publication

(1 citation statement)

References 17 publications

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“…For instance, in the presented experiments, the distance between the tool and the laser beam was 30 mm, and a hypothetical rotation of 0.1 degrees would cause a deviation of 0.05 mm. The current setup therefore has room for improvement, and an additional laser beam could be used to observe these types of deviations [see Figure 8 in (Carlson et al , 2016)]. Additional sensors would motivate state-estimation techniques that supports multimodal probability distributions, such as the method based on particle filtering used by Carlson et al (2016) and Carlson (2019).…”

Section: Error Analysismentioning

confidence: 99%

Robotic friction stir welding – seam-tracking control, force control and process supervision

Karlsson

Carlson

Holmstrand

et al. 2023

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Purpose This study aims to enable robotic friction stir welding (FSW) in practice. The use of robots has hitherto been limited, because of the large contact forces necessary for FSW. These forces are detrimental for the position accuracy of the robot. In this context, it is not sufficient to rely on the robot’s internal sensors for positioning. This paper describes and evaluates a new method for overcoming this issue. Design/methodology/approach A closed-loop robot control system for seam-tracking control and force control, running and recording data in real-time operation, was developed. The complete system was experimentally verified. External position measurements were obtained from a laser seam tracker and deviations from the seam were compensated for, using feedback of the measurements to a position controller. Findings The proposed system was shown to be working well in overcoming position error. The system is flexible and reconfigurable for batch and short production runs. The welds were free of defects and had beneficial mechanical properties. Research limitations/implications In the experiments, the laser seam tracker was used both for control feedback and for performance evaluation. For evaluation, it would be better to use yet another external sensor for position measurements, providing ground truth. Practical implications These results imply that robotic FSW is practically realizable, with the accuracy requirements fulfilled. Originality/value The method proposed in this research yields very accurate seam tracking as compared to previous research. This accuracy, in turn, is crucial for the quality of the resulting material.

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Section: Error Analysismentioning

confidence: 99%