An Affordable Hip Exoskeleton for Assistance and Rehabilitation: Design, Analysis, and Fabrication

Abstract People with physical disabilities or chronic conditions are advised to utilize assistive tools for their day-to-day activities. Making these devices affordable, lightweight, and comfortable to use would increase their practicality for home use and substantially impact the lives of individuals who need them. This work presents a new human-inspired hip exoskeleton design that is cost-effective, and comfortable for the wearer during various movements. This exoskeleton also maintains structural strength and high torque power and is designed to be adjustable and can fit users with varying hip sizes. Furthermore, the large trunk support component features a curved surface intentionally designed to rest on the user’s pelvis, offering added support and effectively preventing any undesired downward movement from the hip. It has one degree of freedom (DOF) and can generate hip movement trajectories in the sagittal plane for both legs. The exoskeleton is fabricated using printable materials like thermoplastic polyurethane (TPU), Polyethylene terephthalate glycol (PETG), polylactic acid (PLA), and carbon fiber to reduce its weight, cost and to make it comfortable and accessible to wider range of end-users. SOLIDWORKS was ussed to design the hip exoskeleton and Ansys was used to perform the FEA on the components. All the components on the hip exoskeleton have a factor of safety (FOS) of a minimum of 3.23. The developed hip exoskeleton including battery, actuators, and electronics weighs 11 kg and is anticipated to be priced below $3,000. The exoskeleton is tested by an able-bodied user weighing 74 kg and 1.74 m tall validating the functionality of all its components. The tests successfully demonstrated that the exoskeleton’s parts efficiently handled the load generated by the motor and hip joint movements. This device is modular and could serve as a base for a full lower limb exoskeleton in the future, which will include components for the hip, knee, and ankle.