As the final assignment for Informal Robotics (Spring 2024), our team was tasked with producing a biologically inspired robot whose motion mimics an animal or insect. We settled on a caterpillar-like robot that would crawl forward.

The Crawling Caterpillar is an under-constrained system that uses friction and the tensioning and releasing of cables to create a crawling motion; the caterpillar robot is also able to fully curl and flatten. We control the tension using two stepper motors to keep track of the amount of string in the two cables spanning the length of the robot.

The joints between the six segments are Delrin rods (creating one rotational degree of freedom), except for the central joint, which uses a universal joint (creating two rotational degrees of freedom.

My role in the team was to design and implement both the electronics (control, battery, charger, circuit board), and a solution for turning the caterpillar.
The robot runs using an Arduino Nano, which handles the commands to the two stepper motor drivers and the servo motor. The Caterpillar is controlled by a remote controller and a IR receiver on the body, and all of this is powered by a Li-Po battery.

For turning, I modified the standard body pieces to allow for some space for a universal joint, and added slots on the sides for tensioning cables. The robot turns by using the servo to tension the two strings on the side.