Toward a 21 Century Crutch Design for Assisting Natural Gait

In order to resolve the disadvantages of conventional crutch designs (i.e. underarm and forearm), a novel crutch design is presented with the name of 21 Century Crutch. Prior the design, human natural treadmill walking is monitored by a 3D Motion Capture System and acquired a reference end–foot trajectory with a ‘teardrop shape’. Considering the design objectives, natural human walking and comfort, and other factors such as load capacity and weight of the device, the final design was determined. In order to satisfy the design objectives, a kinematic synthesis previously worked by Robson and McCarthy [14] is applied to test if the end–foot trajectory of designed crutch smoothly follows the desired reference, ‘teardrop shape’ in the vicinity of two specified task points, heel strike and toe off. For that reason the leg was synthesized and animated in Mathematica as a RR planar kinematic chain, where the first hinge joint/fixed pivot was located at the hip and the other hinge joint/moving pivot is at the knee joint. A prototype of the final design was fabricated and its performance was tested by 2 mph treadmill walking.