A Pneumatic/Cable-driven Hybrid Linear Actuator with Combined Structure of Origami Chambers and Deployable Mechanism

Abstract

Pneumatic actuators have been widely used in robotics due to their inherent compliance and relatively high strength. In this letter, the authors report on the design, analysis and experimental validation of a novel pneumatic/cable-driven hybrid linear actuator whose structure is a combination of origami chambers and passive deployable mechanism. Under the joint actuation of the cable and compressed air, the proposed actuator can generate bidirectional motion; meanwhile, both thrust and tensile force can be produced. The combined structure of the rigid deployable mechanism and the axially soft origami chambers possesses high radial stiffness and an extension ratio up to 200% without radial expansion. The position can be controlled at whole motion range through a simple strategy and the actuation pressure can be as low as 2 kPa at no load. The kinematic as well as the quasi-static model is developed to accurately predict the behavior of the actuator and design the control strategy. A prototype is built based on a new fabrication method, on which the validation experiments are conducted. The experimental results prove the effectiveness of the model and show that the prototype possesses acceptable positioning accuracy, even when an external load is exerted on its moving plate.