The Lego Robot


The Truck is a Lego MindStorms robotic tractor-trailer vehicle. The tractor contains sensors and the steering and drive motors, while the trailer carries the RCX controller and an earthmover. The Truck can back up in a straight line by using the sensors to determine if the trailer is off centre, and applying corrective steering in either direction.

The Truck

The cab houses two motors. The top motor turns the rack-and-pinion steering via a small rubber band, so that the motor is not stalled when the steering reaches the end of its travel. The bottom motor drives two pairs of driving wheels via a differential.

The truck's gearing and sensors

Two touch switches are mounted facing upwards at the rear of the tractor. These contact the underside of the trailer when it begins to pivot in either direction. A light sensor between the driving wheels detects marks on the ground.

The trailer carries the RCX and a bulldozer.

The Truck files:

This program tries to back the truck in a straight line, while beeping to warn any minifigs who might be standing in the way.

More photos of the Truck:

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Copyright © 1998 Ben Williamson