Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism

Karim, Shah; Piano, Samanta; Branson, David; Santoso, Teguh; Leach, Richard; Tolley, Martin

Abstract

This paper presents a real-time position control solution for the targets used in the high-repetition rate laser operations of large-scale high-power laser facilities. The design of the control system is based on an Abbe-compliant, in-process position measurement system of targets, employing a plane mirror interferometer and a five degree-of-freedom hybrid mechanism. An error model has been developed to characterise the position feedback information of the target in a high-repetition rate process to determine the effects of the noncollocation of the interferometer’s measurement point and target on the control system’s performance - a challenge for the real-time position control of targets. The behaviour of the control system is investigated with the error model and experimental data. It was found that the controller’s position compensation scheme can be ineffective due to erroneous position feedback for the non-linear position information representing the non-collocated measurement point and the actual target. To solve the problem, an angular compensation technique is proposed for highaccuracy, real-time position and orientation control of the targets for high-repetition rate processes. The findings of this paper are valid for wider precision applications, e.g. motion control systems requiring highly accurate end-effector position control.

Citation

Karim, S., Piano, S., Branson, D., Santoso, T., Leach, R., & Tolley, M. (2022). Real-time target alignment system for high-power high-repetition rate laser operations using a five degree-of-freedom hybrid mechanism. International Journal of Control, 95(4), 867-885. https://doi.org/10.1080/00207179.2020.1827297

• Journal Article Type: Article
• Acceptance Date: Sep 13, 2020
• Online Publication Date: Dec 4, 2020
• Publication Date: 2022
• Deposit Date: Nov 3, 2020
• Publicly Available Date: Dec 5, 2021
• Journal: International Journal of Control
• Print ISSN: 0020-7179
• Electronic ISSN: 1366-5820
• Publisher: Taylor & Francis Open
• Peer Reviewed: Peer Reviewed
• Volume: 95
• Issue: 4
• Pages: 867-885
• DOI: https://doi.org/10.1080/00207179.2020.1827297
• Keywords: Real-time position and orientation control; in-process metrology; hybrid mechanism; target position feedback; position and angular compensation; complaint and non-complaint feedback information
• Public URL: https://nottingham-repository.worktribe.com/output/5014376
• Publisher URL: https://www.tandfonline.com/doi/full/10.1080/00207179.2020.1827297