Effect of underactuated parallelogram shape-shifting for environmental adaptation movement of a three modular in-pipe robot

Frontiers in Robotics and AI

Robotics and AI

Shugen Ma¹  Atsushi Kakogawa² 

[1] Department of Robotics, Ritsumeikan University, Kusatsu, Shiga, Japan;null;

关键词: underactuation;    differential mechanism;    environmental adaptation mechanism;    in-pipe robot;    crawler module;   

DOI  :  10.3389/frobt.2023.1234835

 received in 2023-06-05, accepted in 2023-09-05,  发布年份 2023

来源: Frontiers

【 摘 要 】

This paper presents an in-pipe robot with three underactuated parallelogram crawler modules, which can automatically shift its body shape when encountering obstacles. The shape-shifting movement is achieved by only a single actuator through a simple differential mechanism by only combining a pair of spur gears. It can lead to downsizing, cost reduction, and simplification of control for adaptation to obstacles. The parallelogram shape does not change the total belt circumference length, thus, a new mechanism to maintain the belt tension is not necessary. Moreover, the proposed crawler can form the anterior-posterior symmetric parallelogram relative to the moving direction, which generates high adaptability in both forward and backward directions. However, whether the locomotion or shape-shifting is driven depends on the gear ratio of the differential mechanism because their movements are only switched mechanically. Therefore, to clarify the requirements of the gear ratio for the passive adaptation, two outputs of each crawler mechanism (torques of the flippers and front pulley) are quasi-statically analyzed, and how the environmental and design parameters influence the robot performance are verified by real experiments. From the experiments, although the robot could not adapt to the stepped pipe in vertical section, it successfully shifted its crawler’s shape to parallelogram in horizontal section only with our simulated output ratio.

【 授权许可】

Unknown   
Copyright © 2023 Kakogawa and Ma.