Motor-based underwater robots cannot implement precise operations in narrow or complicated environments. And smart actuator-based underwater microrobots cannot realize high velocity and long cruising time. For solving these problems, we developed a mother-son robot system that can be used in a wide range of underwater applications.

    ・Propose a mother-son robot system based on the cooperation of motor-based robot and microrobots, to take advantage of both kinds of robots.
    ・Develop an amphibious spherical mother robot for the proposed system.
    ・Develop a mechanism for mother-son robot cooperation.

    The amphibious spherical mother robot consists of an upper hemisphere, 2 openable lower hemisphere hulls, 4 actuating units and a space for carrying microrobots.The mother robot has a diameter of 250mm. One actuating unit is composed of 2 servo motors and a water-jet thruster. By using the actuating units, robot can realize the motions on land and under the water.

    ・By the on-land quadruped walking motions, the robot can adapt to a variety of terrain. The maximal walking speed of the robot is 22.5cm/s.
    ・The robot has a vectored water-jet mechanism. The actuating force can be controlled by PWM signals. The maximal horizontal speed of the robot is 16.1cm/s.
    ・Implement the multi-robot cooperation.