Proposal of a Moving Speed Enhancing Method for Peristaltic Motion Type In-Pipe Inspection Robot with Linear Antagonistic Mechanism Using Endoskeletal Type Artificial Muscles

Abstract

This paper proposes a method to increase the inspection speed of in-pipe robots in long, narrow, and complex pipes with long actuator response time including dead time and rise time due to long fluid tubes. The contributions of this paper include describing the novel approach to increase the moving speed of the peristaltic motion type in-pipe inspection robot with an endoskeleton enhancing propulsion and traction. Through the incorporation of a control method considering dead time, the developed peristaltic motion type robot improved its moving speed by 10.0% under standard pressure conditions. In addition, both theoretical and measured data displayed a similar speed enhancement trend. When integrating the high-pressure application method with the control method considering dead time, the resultant moving speed was found to be lower compared to the method without dead time consideration. This discrepancy can be attributed to the slower contraction response of pneumatic actuators relative to pressure response, leading to insufficient contraction during dead time superimposition. Analyzing the contraction response of the pneumatic tube and actuator used in this study revealed that the unit transitioned to the subsequent movement before achieving optimal contraction. However, the control method considering dead time under standard pressure conditions led to a promising 10.0% improvement in moving speed. This result indicates that the robot holds the potential for delivering both great force and speed in its operations. Experimental observations underscored the preference for applying dead time consideration to standard pressure application rather than high-pressure application methods when aiming to enhance performance.