A Novel Deployable and Stiffness-Variable Homecare Hyper-Redundant Robot Based on the Origami Mechanism

The advantages of hyper-redundant robots lie in their natural flexibility and large deformation, as well as their passive adaptive ability, which shows great potential in medical and nursing applications. However, this feature also makes them weak in scalability and load capacity, making it difficult to complete fine care operations and daily grasping tasks. In this paper, a large deploy/fold ratio variable stiffness hyper-redundant robot based on the origami principle is proposed, which has a large deploy/fold ratio, and realizes large stiffness change based on the bionic muscle-driven variable stiffness principle. Based on the analysis of origami theory, the robot uses rigid origami mechanisms as the skeleton support, flexible gasbags as the backbones, and the hybrid actuation is used to realize the extension, contraction, variable stiffness, and omnidirectional bending motion. Based on the motion/stiffness model of the hyper-redundant robot, the characteristics of the single-joint and the 6-joint hyper-redundant robot are verified by experiments. These experiments confirm that the hyper-redundant robot has a large deploy/fold and variable stiffness range, obtains a large bending deformation and working range, can overcome the gravity generated by itself and the load, and has a high load capacity.