Underwater robot based on flapping

An underwater robot, comprising:

• a pair of actuators, each actuator having a first axis, a second axis orthogonal to the first axis, and a central horizontal plane orthogonal to the second axis, each actuator including:
• a first smart material having a longitudinal axis parallel with the central horizontal plane of the actuator and orthogonal to the first and second axes, and a second smart material having a longitudinal axis parallel with the central horizontal plane of the actuator and the longitudinal axis of the first smart material, and a directional material, the first smart material bending the actuator in a first direction and the second smart material bending the actuator in a second direction, and
• an anisotropic directional material in the central horizontal plane of the actuator that twists the actuator when the first and second smart materials bend the actuator,
• wherein each of the first and second smart materials changes its shape according to an external signal, and the directional material restricts a deformation of the actuator;
• a body connected with each of the pair of actuators;
• and
• a controller which makes the pair of actuators perform a first stroke in the first direction, and a second stroke in the second direction;
• wherein the first and second smart materials extend from the body into each of the actuators, and the actuators simultaneously bend and twist according to positions of the first and second smart materials and a directionality of the anisotropic directional material.