Motorised shoe mechanisms to apply chaotic perturbations for gait training

Motorised shoes have been developed to apply chaotic perturbations for gait training. Each shoe comprises four individually controlled actuators, two in the heel and two in the forefoot. Rapid speed of actuator movement has been achieved with the use of a slider-connecting rod-crank mechanism. The mechanism was constructed in a 3D model and checked for component interference using kinematic analysis. Force analysis was undertaken using Euler rotations of each segment in co-ordinate transformation matrices. Component drawings were transferred to a finite element analysis package and factors of safety were applied for a fatigue life of 60,000 steps for each actuator. Latterly that has been extended and one of the pairs of shoes has undertaken 250,000 steps without serious problems. Four pairs of shoes are currently in trials with approximately 100 users. Future work will focus on weight reduction, increased load capacity and extended fatigue life.