Monitoring method of interactive torque between human and robot in exoskeleton systems

In this paper, a model based interactive torque estimation method for exoskeletons is proposed. For this purpose, the dynamic model based disturbance observer (DOB) is adopted to estimate the interactive torque instead of using force/torque sensors. Also, a parameter identification method is applied to enhance the precision of estimated torque against various uncertainties in the dynamic model. In order to classify interactive torque from the estimated disturbance signal of DOB, the information on generated actuator torque is required. By the actuator impedance model, the generated actuator torque can be estimated precisely. The proposed methods were implemented in SUBAR (Sogang University´s Biomedical Assist Robot) and verified by experiments.