Researchers at UCLA have created a new design for a swimming robot that is powered and steered by constant light. The robot the team devised is called the OsciBot and it moves by oscillating its tail. Researchers hope that the design might eventually lead to designs for ocean-going robots and autonomous ships.
The design of OsciBot was inspired by a natural phenomenon called phototaxis, which is movement towards or away from a light source. Phototaxis is found in the animal kingdom. The OsciBot shows that a robot moving by oscillation can be directly powered by constant light rather than relying on energy harvested by solar panels and stored in a battery.
The robot is made from a soft hydrogel material that swells when placed in water and is responsive to light. The design requires no batteries and doesn’t need to be tethered to a power source. During the research, the team built a 2cm long, flexible cylinder and anchored it to the bottom of a water tank. When a beam of light was directed at the cylinder, the team found that the light made the cylinder bend as fast as 66 times per minute.
They also found that by moving the position of the light source, they could direct the device to bend both left and right and up and down. The speed of the oscillation can be adjusted based on the length of the cylinder, its thickness, and how much light is used.
Researchers created a robot that looks like a rectangular surfboard with an extended underwater tail. When light from a laser hits a spot on the tail of the robot, the spot heats up. The slight increase in temperature causes that part of the robot to eject some of its water and shrink in volume, moving the tail towards the light source. When the tail moves up, it creates a shadow, and the spot cools making the tail descend. The bot was able to move 1.15 times its body length per minute.