# COCrIP: Compliant OmniCrawler In-pipeline Robot

## TL;DR

This paper introduces a modular, compliant OmniCrawler robot designed for in-pipeline navigation, featuring a novel foldable mechanism and optimized joint stiffness to negotiate bends and slippery surfaces effectively.

## Contribution

The paper presents a new compliant foldable OmniCrawler design with optimized joint stiffness for improved pipeline navigation, validated through simulations and real-world experiments.

## Key findings

- Successfully navigates sharp bends in small diameter pipes
- Achieves traction on slippery surfaces
- Validated design through experiments

## Abstract

This paper presents a modular in-pipeline climbing robot with a novel compliant foldable OmniCrawler mechanism. The circular cross-section of the OmniCrawler module enables a holonomic motion to facilitate the alignment of the robot in the direction of bends. Additionally, the crawler mechanism provides a fair amount of traction, even on slippery surfaces. These advantages of crawler modules have been further supplemented by incorporating active compliance in the module itself which helps to negotiate sharp bends in small diameter pipes. The robot has a series of 3 such compliant foldable modules interconnected by the links via passive joints. For the desirable pipe diameter and curvature of the bends, the spring stiffness value for each passive joint is determined by formulating a constrained optimization problem using the quasi-static model of the robot. Moreover, a minimum friction coefficient value between the module-pipe surface which can be vertically climbed by the robot without slipping is estimated. The numerical simulation results have further been validated by experiments on real robot prototype.