I designed this robot for a navigation contest which took place during the 9th Italian Legofest. Each robot had to start from a given point, go straight for a short distance until touching a wall, turn itself 180° and go back more precisely as possible to the starting point. The rules were very detailed, but the major points were that rotation sensors were forbidden and that the robot had to actually turn, it couldn't simply reverse its motion. The initial distance from the starting point to the wall was 1m, and we performed five rounds with increasing distances, adding 1m at each new round up to a final distance of 5m.
"Andata" is the first of the two robots I prepared for the contest. Though it did not win the contest, it performed very well, reaching the final round and proving itself always very precise and very reliable. On the maximum distance of 5m, after the round trip it was no more than 4-5cm far from the reference point.
It can be considered a differential drive, though of a special kind. There is
only one drive motor, which powers the right wheel. When the robot is required
to go straight, a simple mechanism keeps the left wheel coupled to the right
one, so they travel at exactly the same speed. This solution makes the robot go
When the robot needs to turn, a group of pneumatic cylinders disengages the mechanical coupling, and at the same time brakes the left wheel. Doing so, the robot can turn pivoting around its locked left wheel.
For the contest, the robot needed only a limited supply of compressed air, so I adopted the solution of pre-loading the tank with a manual pump.
The long red axle protruding from the front of the robot has the purpose to close a touch sensor when the robot hits the wall.
This page is not connected with or endorsed by The LEGO Company. LEGO, LEGO TECHNIC and LEGO MINDSTORMS are trademarks of The LEGO Company.