Abstract
Safety is one of the most important issues in human-friendly robots. We have proposed a velocity and contact force-based safety device for human-friendly robots and developed a wheeled mobile robot equipped with the safety devices. The safety device consists of only passive components without actuators, controllers, or batteries. The safety device has the "velocity detection mechanism", the "contact force detection mechanism", and the "switch-off and shaft-lock mechanism". However, the contact force detection mechanism may resonate with a robot vibration when the robot moves on a rough surface, because the mechanism has a plate, and two springs, that is, the mechanism is a mass-spring system. In this paper, we firstly review the robot with the safety devices. Secondly, we analyze the frequency response of the contact force detection mechanism. Thirdly, we propose a method to prevent the contact force detection mechanism from resonating with the robot vibration. Finally, we present experimental results to verify the usefulness of the proposed method.
