A mobile microrobot actuated by a new electromagnetic wobble micromotor

Microactuators are perhaps the most critical components of micromechatronic systems. Micromotors with diameters in the range between 10-1 mm are needed, but are not readily available for practical use. This paper describes a teleoperated mobile microrobot, actuated by a new electromagnetic wobble micromotor, and designed to participate in the “International Micro Robot Maze Contest" organized every year in Nagoya, Japan. This competition is an excellent benchmark to compare the performance of different microactuators. The working principle, design, fabrication, and performance of the wobble micromotor are described. The microrobot has a volume of 1 cm³ and incorporates two wobble micromotors, the rotors of which are the driving wheels. The micromotor generates a torque of 350 μN·m at each step and a maximum speed of about 180 r/min. The operator controls the motion of the microrobot by a remote joystick connected to the microrobot by flexible ultraminiature wires. The microrobot is highly maneuverable, has a maximum speed of 10 cm/s and can climb a slope of 15°. Two microrobots, which differ only in some constructive details, were fabricated. A smaller version (4-mm diameter) of the wobble micromotor has been developed for use in an innovative miniature robot system for diagnosis and intervention in the colon