Researchers learn how to control soft robots using compressed air
Engineers at the University of California, San Diego have created a four-legged soft robot that does not require electronics to operate. The robot is controlled and moved with a constant source of compressed air.
Most of today's soft robots are powered by compressed air and are electronically controlled. But this requires complex components such as circuit boards, valves, and pumps. They are usually bulky and expensive.
The new robot is controlled by a lightweight and inexpensive pneumatic circuit system consisting of tubes and soft valves mounted on it. The device can walk on command or in response to signals that it receives from the environment.
The robot's computational power roughly mimics the neural responses of a mammalian spine.
To mimic the functions of generators, engineers built a system of valves that act as oscillators, controlling the order in which compressed air enters the muscles of the four limbs of the pneumatically operated robot.
In addition, the researchers created an innovative component that coordinates the gait of the robot by delaying the flow of air into its legs. The gait of the robot simulates the movement of a turtle.
It also has simple mechanical sensors - small soft bubbles filled with liquid located at the ends of arrows protruding from its body. When the bubbles descend, the liquid flips the valve, forcing the robot to change direction.
Each of the robot's four legs has three degrees of freedom, driven by three muscles. The legs are angled downward at a 45-degree angle and consist of three parallel-connected pneumatic cylindrical chambers with bellows. When the chamber is pressurized, the limb flexes in the opposite direction. As a result, three chambers in each limb provide the multi-axis bend required for walking. The researchers connected cameras on each leg diagonally from each other, making it easier to control.
The soft valve switches the direction of rotation of the limbs counterclockwise and clockwise. This valve acts as a latching two-pole DIP switch.
The authors of the development note that it can be used both in the field of entertainment for the development of inexpensive robots and in those environments where electronics cannot work. For example, robots can be placed inside an MRI machine or in a mine. The development can be used in the work of more highly organized robots that will move through pneumatics, and execute commands under the control of electronics.
In the future, researchers want to improve the robot's gait so that it can navigate natural terrain and uneven surfaces. This will require a more complex sensor network and, as a consequence, the development of a more complex pneumatic system.
Earlier, UCLA engineers showed a squid robot that can autonomously swim by releasing jets of water. The robot is equipped with its own energy source. It can be used for underwater research. The device is already equipped with special sensors for this job.