Mechanical design for a cable driven upper limb exoskeleton prototype actuated by pneumatic rubber muscles

This paper describes the mechanical design of a prototype of a 4 degree of freedom upper limb exoskeleton suit. A cable driven system actuated by an array of pneumatic muscles, located at the back of the suit, was implemented in the prototype. The developed design aims to enhance human upper body strength for applications ranging from the rehabilitation of stroke patients to enabling workers and soldiers to carry heavy loads for prolonged periods of time. Pneumatic systems with pneumatic artificial rubber muscles have demonstrated their ability to enhance load-carrying capabilities of human muscles, while matching the range of speed these muscles are capable of undergoing. The design presented in this paper builds on previously used pneumatic systems by incorporating a cable-driven robotic arm. The system was controlled based on the handled weight and desired arm's range of motion. A load cell was used to detect and measure the applied load while a potentiometer was used to measure the angle reached by the arm. The developed upper limb exoskeleton robot arm was able to carry 8 kg. With some improvements, the current design could be transformed into a wearable upper limb exoskeleton suit capable of carrying twice the achieved weight goal.