Response to assist torque failure of physical-assistant robots

In physical assistant robots used to mitigate burden on the lumbar, there is a risk that if the assist torque is lost, excessive burden may be applied to the lumbar. Therefore, for some products, a system to lock the moving parts on the lumbar is examined as a prevention measure against this risk. Through an experiment on a subject who wears test equipment that simulates a physical-assistant robot, the myogenic potential at the lumbar when the assist torque was lost was measured. Results indicated that if the moving part is locked within 151 msec after the loss of assist torque, the load of the lifted baggage can be supported by the frame of the robot and thus the burden on the user can be mitigated.