Force-cooperative guidance design of an omni-directional walking assistive robot

This paper presents a novel force-cooperative guidance controller design for a walking assistive robot such that it can guide an elderly or handicapped person in an indoor environment. The guidance system has been implemented on a walking helper robot (Walbot) to allow the robot to incorporate passive behaviors. A handrail was provided for Walbot to facilitate passive walking assistance using an omni-directional mobile platform. A laser scanner is used for environment detection and obstacle avoidance. A mass/damper model regulates robot velocity with respect to applied external force. In this paper, we propose a method to fuse output from the compliant motion controller and the autonomous navigation controller in order to give the robotic walker a safe and passive walking guidance. Force-cooperative guidance is achieved by giving proper output-fusing weights to each controller such that the walking help robot can follow the motion intent of the user while avoiding obstacles appearing in the environment.