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Bendy robotic tank steers by flexing

Arduino TeamApril 24th, 2023

James Bruton has become something of a YouTube sensation by experimenting with unusual drive mechanisms for his robots. While he does do other things, most of his projects seem to focus on designing, building, and evaluating drive types that are far outside of the norm. His newest project is no different. It is a single-track tank vehicle that steers itself by bending its entire body.

Bruton got this idea after looking at the way conveyor belts work. Those belts, which tend to be a series of interconnected segments, are obviously flexible along their length, which is necessary for them to bend and loop back around. But they are also slightly flexible in the direction perpendicular to that, which is necessary for the conveyor belt to make a turn. Bruton figured that if he could make a tank track bend in a similar way, he could make the vehicle turn without the need for a second track.

To test this idea, Burton 3D-printed almost the entirety of the vehicle. That includes the track itself, which is made of several rigid segments that link together. There is just enough movement in the connections to allow a segment to sit at an angle relative to its neighbors. Conventional motors in front and back units spin the track, and an Arduino Mega 2560 board controls them. Between the two units is a joint that pivots horizontally. A linear actuator arm controls the angle between the front and back units, forcing the track to bend.

While the turning radius is massive, this vehicle can maneuver. It isn’t very good at clearing obstacles, but that is more due to Bruton’s design than the drive and steering system. That could be improved with additional design iterations, but this vehicle already proves that the concept works.