A four-legged soft robot that doesn’t need any electronics to work

A team of engineers from the University of California San Diego has unveiled a prototype four-legged soft robot that doesn’t need any electronics to work. The robot only needs a constant source of pressurized air for all its functions, including its controls and locomotion systems.

Most soft robots are powered by pressurized air and are controlled by electronic circuits. This approach works, but it requires complex components, like valves and pumps driven by actuators, which do not always fit inside the robot’s body.

In contrast, this new prototype is controlled by a lightweight, low-cost system of pneumatic circuits, consisting of flexible tubes and soft valves, onboard the robot itself. The robot can walk on command or in response to signals it detects from the environment.

Engineers built a system of valves that act as oscillators, controlling the order in which pressurized air enters air-powered muscles in the robot’s four limbs. The gait of the robot was inspired by sideneck turtles’ movements. Each of the robot’s four legs has three degrees of freedom powered by three muscles. When a cylindrical chamber is pressurized, the limb bends in the opposite direction.

As a result, the three chambers of each limb provide the multi-axis bending required for walking. Researchers paired chambers from each leg diagonally across from one another, simplifying the control problem. The robot is also equipped with simple mechanical sensors, small soft bubbles filled with fluid placed at the end of the bars protruding from the robot body. When the bubbles are depressed, the fluid activates a valve that causes the robot to change direction.

What makes this soft robot more impressive is, it can move and sense what’s in its environment, turning around or sideways when confronted by an object, without using any electronics.

The developers are confident that such cheap, simple, and reliable systems will find wide application not only in gaming and entertainment but someday they will be used in environments where electronics cannot function, such as MRI machines or mine shafts.

The team’s next step is to improve the robot’s gait so it can walk on natural terrains and uneven surfaces. This will allow the robot to navigate over a variety of obstacles.

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