A Torsional Pneumatic Joint for Spacesuit Inspired with Origami Structure

Abstract

For exploration of the deep space destinations like the planetary surfaces, one of the most significant challenges is the performance of the spacesuit system. Aimed at improving safety and flexibility for the human-suit system during extravehicular activities (EVAs), a novel torsional pneumatic joint (TP joint) is proposed inspired with origami structure, overcoming the defects of traditional airtight bearings. Geometry of the TP joint is designed with Kresling crease pattern at first. To study the mechanical property of the TP joint, a basic structure of two layers is abstracted and analyzed with the energy method and nonlinear finite element method. According to analysis, the constitution of resistance torque is discussed and two influence factors of material rigidness and air pressure are investigated. As the inner pressure becomes large, the inflatable structure is unstable and tends to swell asymmetrically. Meanwhile, based on an eight-layer prototype joint, torsional and bending tests are conducted under inner pressure to examine the mobility of the joint. Results show that the prototype joint can be twisted to a range of 40°in one direction, and the torque is much smaller than the critical buckling torque of a pneumatic tube. Besides, the prototype joint also equips the bending function with a relatively low torque as an ordinary soft spacesuit joint. Thereby, the proposed TP joint can realized the torsional operations and has the potential to function as rigid bearings. Besides, the TP joint can be designed as a multi-degree joint to provide more mobility for the spacesuit system.