Researchers Develop “Brainless” Rubber Band-Powered Robots

Harvard John A. Paulson School of Engineering and Applied Sciences researchers have developed a robot that can navigate away from obstacles and sort objects…all without an electronic brain. Dr. Katia Bertoldi’s mechanical engineering team developed a robot that uses a set of mechanical antennae that act as feelers to find its way through mazes or sort objects based on mass.

According to Leon Camp, a graduate student who led the research, “This is kind of an extreme version of ‘form follows function.” The robot’s intelligence does not come from an onboard computer. Instead, it is derived from geometry, materials properties, and other physical phenomena.

The newly developed robot can navigate a maze without a brain, but this guy fought flying monkeys and navigated to Oz without one! Image used courtesy of Wikimedia Commons

Mechanical Programming for Robotics

Instead of relying on costly sensor arrays, complex computing, machine vision, and artificial intelligence, the Harvard research team developed a method of mechanical programming. As the rubber band-powered robot moves, it gently bumps objects around it. Each tap of the antenna causes it to mechanically react and spool a motor in one direction or another. Then, the motor can take the next step in the correct, obstacle-free direction, based on which way the motor is moving.

In the working prototype, researchers used one motor and four rubber bands to create a walking robot capable of performing these tasks. Based on the placement of the rubber bands, the robot can perform different actions based on the mechanical feedback.

Component blocks are joined by rubber bands and “programmed” based on the position of the bands. For example, one placement may allow blocks to slide past each other, while moving the rubber band slightly causes the blocks to “lock” in place. Additional rubber band settings may control the speed at which the block responds, based entirely on the tension of the rubber band.

The robot steers itself via antennae. If an antenna gently touches an object on its left, the robot is steered to the right via mechanical feedback. Video used courtesy of Harvard John A. Paulson School of Engineering and Applied Sciences

A Rubber Band-Powered Robot

Will “brainless” robots take over? Not quite. These robots are designed for certain niche applications. They can perform simple tasks without relying on extensive and expensive computing power and sensors. They can be constructed at low costs and be easily adjusted for different tasks just by changing the positions of the rubber bands.

The next steps will be increasing their speed and allowing them to jump over obstacles, increasing their utility for simple tasks. Hybrid systems are also possible, where simple tasks are performed mechanically, while more complex control is performed electronically, extending the battery life and making a more efficient robot overall.

While the mechanical feedback mechanism of the rubber bands is the focus of these robots, this research is the first step in other mechanical programming mechanisms. For example, perhaps a similar robot could rely on the compression or stretching of a spring, the phase change of shape alloy, or some other physical property as a source of actuation for robotic movement.

Featured image used courtesy of Harvard John A. Paulson School of Engineering and Applied Sciences