Hybrid Hard-Soft Robotic Joint and Robotic Arm Based on Pneumatic Origami Chambers

Soft robotic arms are actively being researched due to their high potential, but they still face challenges in terms of controllability due to their infinite degrees of freedom (DOFs). Hybrid hard-soft robotic arms have been proposed as a solution, but their performance is limited by only operating under positive or negative pressures due to the pneumatic chambers collapsing under a negative pressure. In this article, we propose an origami-based pneumatic robotic joint that can utilize both positive and negative pressures through the origami structure guiding the motion through both expansion and contraction of the chamber. This origami chamber is combined with a hard rotational structure, forming a hybrid hard-soft robotic joint. A single-chamber bidirectional joint and a dual-chamber joint with two antagonistic chambers were developed. Their range of motion, load-lifting capacity, and control performance under positive and negative pressures were evaluated. These joints were assembled into multi-DOFs joint which were easily controlled through decoupled controllers for each DOF and implemented into a 3-DOFs robot manipulator that could perform pick-and-place operations with objects weighing over 1 kg.