Efficiency improvement of walking assist machine using crutches based on gait-feasible region analysis

• Quantitative evaluation of gait characteristics of developed walking assist machine
• Investigation of suitable control parameter region to achieve safe gait
• Mechanism improvement for effective gait achievement and better ride-comfort
• Simulation/experimental validation to demonstrate the achievement of safe walking
• Experimental demonstration on reduction of energy consumption by proposed mechanism

To improve gait efficiency of a walking assist machine using crutches (WAMC), a parameter study has been carried out to introduce the gait-feasible region (GFR). GFR is the region of a set of state variables of WAMC in which safe gait can be achieved. Evaluation indices for energy consumption and ride comfort are derived. On the basis of these indices with GFR, design of suitable control input parameter to achieve efficient and comfortable gait is discussed. A foot-driving mechanism (FDM), which amplifies the actuator input to generate quick rotation of foot without an additional actuator, is introduced to improve energy consumption and ride comfort of WAMC, and its simple and practical composition is presented. On the basis of the results of several simulations and experiments using a prototype, validity and effectiveness of the proposed methodology are demonstrated.