IMU sensor based human motion detection and its application to braking control of electric wheeled walker for fall-prevention

With the increase in the aging population of developed countries, the demand for walking assisting devices has grown. Walkers are widely used because they provide high mobility and safety. In this paper, an electric wheeled walker (EWW) is used to prevent the user from falling down. This paper presents novel fall prevention systems that are composed of a human motion detecting algorithm and a braking system. The motion detecting algorithm focuses on the reaction torque of the EWW and the acceleration of the user. The reaction torque is estimated by the reaction torque observer (RTOB), and the acceleration is measured by using one IMU sensor. The braking system works by switching commands on the basis of human motion. Four motions are considered, and if the user motion is detected as dangerous, the command value switches, and braking is initiated in response to the user posture. Experiments are performed to verify the effectiveness of the proposed algorithm and controller.