Yasuhisa Hirata

PASSIVE INTELLIGENT WALKER CONTROLLED BY SERVO BREAKS

We propose a new intelligent walker based on passive robotics that assists the elderly, handicapped people, and the blind who have difficulty walking. We developed a prototype of the RT Walker (Robot Technology Walker), a passive intelligent walker that uses servo brakes. The RT Walker consists of a support frame, two casters, two wheels equipped with servo brakes, and it has passive dynamics that change with respect to applied force/moment. This system is intrinsically safe for humans, as it cannot move unintentionally, i.e., it has no driving actuators. In addition, the RT Walker provides a number of navigational features, including good maneuverability, by appropriately controlling the torque of servo brakes based on robot technology. We propose an environmentally-adaptive motion control algorithm, which incorporates environmental information to provide obstacle/step avoidance and gravity compensation functions. The proposed control algorithms are experimentally applied to the RT Walker to test their validity.

A COOPERATIVE TRANSPORTATION SYSTEM OF A CAR WITH MULTIPLE MOBILE ROBOTS: ICART II

In this paper, a new car transportation system and a prototype robot that are based on the “a-robot-for-a-wheel” concept are introduced. In addition, a decentralized control algorithm for cooperative car transportation using a leader–follower type of multiple robot system is proposed. An external force compensation method is explained for extracting only internal force from the force applied to the robots. The proposed algorithm is experimentally validated by application to a car transportation system. Finally, the application of the proposed system to medical and welfare mobile apparatuses is described.

Motion control of a passive robot for dancing with a male dancer

A novel motion control algorithm was introduced to achieve dance between a man and a passive type robot (PDR), which can not move by itself, but can guarantee higher level of safety in the process of human-robot cooperation. Firstly, the characteristics of servo brake were analyzed, and the motion was divided into 8 states according to the kinematic model and control constraint condition. Then feasible brake torque set was obtained, which is a subset of whole brake torque, this makes control of passive type robot more complicated than general mobile robots. When the desired force is within this set, the brake torque for each wheel can be derived with static equation, otherwise, the assistance force applied by male dancer is employed. Finally, non-time based path tracking control was proposed for dance step tracking. The motion control algorithm was verified by two typical dance steps, and experimental results demonstrated the validity.