Identification of the most conservative stability bounds for a class of multi-rate haptics controllers. (11th January 2023)

• Record Type: Journal Article
• Authors: Ganiny, Suhail; Koul, Majid H.; Ahmad, Babar
• Is Part Of: International journal of modelling, identification and control. Volume 41:Number 4(2022)
• Page Start: 357
• Page End: 374
• Publication Date: 2023-01-11
• Subjects: multi-rate controllers -- impedance haptic interfaces -- stability bounds; Engineering -- Methodology -- Periodicals; Science -- Methodology -- Periodicals; 001.42
• Languages: English
• ISSNs: 1746-6172

Abstract

This work identifies the most conservative stability bounds applicable to a class of multi-rate haptics controllers that involve sampling of a single state variable at two distinct rates for rendering a virtual wall. In particular, the uncoupled stability boundaries of a dual-rate haptics controller have been determined. In contrast to the prior research, the current work extends the scope in terms of identification of the impedance parameters that establish the worst-case stability limits that are closest to the experimental results. Our analysis reveals that the transformation sequence 'ZOH-Tustin-ZOH' yields the most conservative, while the 'half-sample delay approximation' approach yields the least conservative estimates of the stability bounds. Specifically, the relative root-mean-square error (RRMSE) between the experimental outcomes and the results predicted by the 'ZOH-Tustin-ZOH' transformations vary between 0.54-0.83, while for the 'half-sample delay approximation' it varies from 1.21-3.2, respectively.