Abstract
Safety is one of the most important issues in robot suits. We have developed a robot suit with two hardware-based safety devices - the "velocity-based safety device" and the "torque-based safety device". The robot suit assists a patient's knee joint. The velocity-based safety device switches off the motor if it detects unexpected high joint angular velocity. Similarly, the torque-based safety device switches off the motor if it detects unexpected high joint torque. The safety devices can work even when the computer breaks down, because they consist of only passive mechanical components without actuators, controllers, or batteries. In this paper, we design a new robot suit with hardware-based safety devices which is more compact than the previous one.
