A proposal of small linear actuators for small entertainment robots

This paper describes about a small linear actuator. In recent, there have appeared miniature direct current electric (DC) motors. Then, we propose a linear actuator consisting of a DC motor, a pair of spiral springs and cylinders. The principle of the actuator is simple. The DC motor rotates a spring directly. The rotated spring gears the other one and goes in or out of the spiral interspace. As a result, the actuator elongates and contracts. Our actuator is controlled by a ON-OFF signal and inversion of a current. We made the actuator experimentally and constructed a light and small locomotion robot with proposed actuators as an application. In simulation, we obtained parameters for locomotion of the robot by using genetic algorithm. The robot realized walking by switching on or off the current and changing the polarity of the current.