Development of a walking support system controlled by servo brakes

We have developed a passive-type walking support system equipped with a lift device which provides a patient with partial body weight support and prevents the patient from falling down. The lift device has a constant force spring and an electromagnetic powder brake. The constant force spring is used in order to provide the patient with partial body weight support. The powder brake is used in order to prevent the patient from falling down. In this paper, we propose a new passive-type walking support system equipped with not only the lift device but also a treadmill. The treadmill has an endless belt controlled by an electromagnetic powder brake and an electromagnetic clutch. This system is essentially safe, because it consists of only passive components with no active actuators. The system normally provides the patient with partial body weight support. If the patient is likely to fall down, the system prevents the fall by engaging the treadmill´s clutch and applying impedance control to the powder brakes. We present experimental results to verify the effectiveness of the treadmill.