Whether you’re working with a car, truck, motorcycle, bicycle, or robot, you always need to consider the tradeoff between smooth wheels that work on concrete and other refined surfaces, and more knobby tires that let you stomp through rough terrain. However, this “Adaptive Field Robot” from a team of masters students in Belgium, and inspired by research from the National Taiwan University, is able to do both jobs well — thanks to wheels that convert from a circular shape to what looks like a pair of claws.
To do this, the bot uses a motor-powered wheel on each side, with a pair of unpowered wheels on the back to form a classic two-motor robotic control setup. The trick is that it actually uses four motors, two for each wheel. One motor per wheel is used to turn the assembly and thus move the bot, while the other rotates with the wheel under normal circumstances. When needed, this second motor then activates a rack-and-pinion system to push two halves of the wheel out. This transforms it into something that looks more like a claw, allowing it to pull itself over obstacles.
Everything is controlled by an Arduino Uno board, along with a pair of L298N H-bridge drivers and an ultrasonic sensor scans the floor for changes in order to detect uneven patches for "claw" deployment. A demo of the build is seen in the video above. Though (like any project) there were definitely challenges getting it to work properly, the concept could be extremely useful in multi-role machines.