Lesson Plan/Activity
Snake Robot Ages: 12-99
In this project I wanted to construct a remote controlled robot which moves much like a real snake. The snake robot consists of four links and three joints, being the motor axels. Each link is equiped with a set of free rolling wheels. The serpentine motion of a real snake is only possible due to anisotropic friction, i.e. the friction in the longitudinal direction of the snake is smaller than in the lateral direction. This is not so easy to mimick with a robot, especially not with Lego bricks. Instead of letting the robot "slide", I use the non-actuated (free) wheels. The NXT on the robot steers the motors such that each joint performs a sinusoidal motion, but each with a different phase, such that a wave is running through the snake robot. This is enough for straight motion. Turning left or right is accomplished by setting an offset on the motor angles, i.e. the robot forms a "banana" with a superimposed sinusoidal wave. The NXT on the robot is in Bluetooth connection with a steering device (another NXT).

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