A Large-Scale Inflatable Robotic Arm Toward Inspecting Sensitive Environments: Design and Performance Evaluation

Abstract

As a subdomain of soft robots, inflatable robotic arms (IRAs) offer a promising alternative to inspect the sensitive environments that entail highly compliant manipulation, e.g., disaster rescue or archaeology exploration. This article presents a lightweight (only 843 g in weight) and 10.1-m-long deployable IRA that is a portable integration of mechanisms, electronics and pneumatics. The actuation, fabrication and sensing of the IRA are firstly elaborated on from the perspective of joint modularization. Antagonist pneumatic artificial muscles (PAMs) are leveraged to enable the 10-degrees-of-freedom (-DOF) motion of the thin-walled and Helium-inflated body. The hardware-in-the-loop system is established, with the pneumatic components integrated into a compact box. Given the limited position accuracy of the environmentally compliant IRA, a custom-designed joystick input interface is incorporated to achieve human-in-the-loop teleoperation, thereby enhancing the situational awareness. The control architecture, covering the actuator, joint and task spaces, is employed to address the model uncertainties that are induced by both the IRA itself and the cluttered environments. Long-range inspection demonstrations that associate with obstacle avoidance and high-precision navigation are performed in typical simulation scenes like complex terrains and relic/plant environments. Experimental results ultimately reveal the promising performance of the developed IRA, enabling its future deployment in inspection.