Design and Fabrication of a Low-cost Human Body Lower Limb Exoskeleton

Recent developments in exoskeleton technology have assisted humans in performing strenuous and fatiguing tasks. However, these exoskeletons are unable to reach masses due to their high cost. In this paper, design, fabrication and validation of a low-cost human body lower limb hybrid exoskeleton is presented. The exoskeleton provides assistive torque at the hip and knee joints which prevents strain on the limbs of the user. The exoskeleton is designed to work with joint actuators made of electric dc motors coupled with back-drivable custom gearboxes. A prototype of the same is fabricated and tested. The joint angle data required to mimic a walking gait cycle was collected by filming subjects walking on a treadmill with the help of a camera whereas joint torque data was obtained by performing inverse dynamics on a musculoskeletal model. The exoskeleton model was simulated in MATLAB Simulink. The torque profiles produced by the joint actuators are plotted and compared with required torque profiles. Percentage torque assists at the hip and knee joints are calculated and discussed.