Improvement in modeling of Walking Assist Machine Using Crutches for dynamic analysis

In a previous study, a gait assistive device embodying actuators, known as Walking Assist Machine Using Crutches (WAMC), was proposed for people who suffer from lower limb disabilities. Experiments with healthy subjects show that WAMC can provide upright stance position and assisted forward gait to the user. However, the simplistic kinetostatic model used in gait analysis does not permit to obtain forces and torques acting on the system (user and WAMC) in detail. In this paper, an anthropometric 2D model which can investigate the gait characteristics of the system is proposed. Force and torques acting on the system parts can be guessed prior to the experiments if the user's height and weight are specified. This will also help increasing the consistency between the dynamic simulation results and the input parameters required for experiments. Results of the gait analysis show that the model can successfully reproduce the kinematics of the system joints derived from experiments. In addition, it is shown by dynamics analysis that WAMC provides a comfortable ride as the forces and torques acting on the system are in admissible limits.