Development of an underwater biomimetic microrobot with compact structure and flexible locomotion

Compact structure and flexibility is normally considered as a pair of incompatible characteristics for legged microrobots. Most robots choose complex structure of multi-joint legs to attain the flexibility, while some microrobots have poor flexibility for miniaturization. To attain a microrobot with both compact structure and flexible locomotion, we designed a novel type of biomimetic locomotion employing ionic conducting polymer film (ICPF) actuators as one-DOF legs. We developed several prototype microrobots using this locomotion. In this paper, a microrobot using this biomimetic locomotion, named Walker-3, utilizing six ICPF actuators with two-DOF motion is developed. It is 30 mm in length, 55 mm in width and 8 mm in height (in static state). Experimental results indicate that Walker-3 can attain 6 mm/s of walking speed and 7.1 deg/s of rotating speed and climb on a 30° ascent at a speed of 0.5 mm/s with control signal of 10 V, 0.5 Hz. It is also suitable for uncertain terrain, such as climbing on a stairs less than 2 mm high and striding over a pit less than 5 mm wide. It has better flexibility, balance and load ability than its predecessors. We compared it with some legged microrobots and the result shows a microrobot with this biomimetic locomotion can have both compact structure and multi DOF locomotion.