Micrometer Positioning Accuracy With a Planar Parallel Continuum Robot.

Benjamin Mauzé,Redwan Dahmouche,Guillaume J Laurent,Cédric Clévy

doi:10.3389/frobt.2021.706070

Abstract

Parallel Continuum Robots (PCR) have several advantages over classical articulated robots, notably a large workspace, miniaturization capabilities and safe human-robot interactions. However, their low accuracy is still a serious drawback. Indeed, several conditions have to be met for PCR to reach a high accuracy, namely: a repeatable mechanical structure, a correct kinematic model, and a proper estimation of the model’s parameters. In this article, we propose a methodology that allows reaching a micrometer accuracy with a PCR. This approach emphasizes the importance of using a repeatable continuum mechanism, identifying the most influential parameters of an accurate kinematic model of the robot and precisely measuring them. The experimental results show that the proposed approach allows to reach an accuracy of 3.3 µm in position and 0.5 mrad in orientation over a 10 mm long circular path. These results push the current limits of PCR accuracy and make them good potential candidates for high accuracy automatic positioning tasks.

Highlights

Parallel Continuum Robots (PCR) are a recent and rising type of robots introduced in (Bryson and Rucker, 2014)
Resulting robots present a higher rigidity than soft robots while keeping most of their advantages
The continuum Steward-Gough platform introduced in (Bryson and Rucker, 2014) had its dimensions reduced in order to create a surgical PCR whose platform is around 10 mm diameter (Orekhov et al, 2017)

Summary

Introduction

Parallel Continuum Robots (PCR) are a recent and rising type of robots introduced in (Bryson and Rucker, 2014). The continuum Steward-Gough platform introduced in (Bryson and Rucker, 2014) had its dimensions reduced in order to create a surgical PCR whose platform (a gripper) is around 10 mm diameter (Orekhov et al, 2017). This small prototype illustrates the interest and the capability of PCR to perform applications inside confined space (like the human body) where instrumentation and sensor-based controls are difficult to implement. The objective of this paper is to propose a methodology to reach a high accuracy with PCR by measuring, identifying and understanding the influence of the different parameters, and have an estimate of a typical level of accuracy that a PCR can reach

Results

Discussion

Conclusion