Group 1
Introduction to Intellegent Robotics
CS 4970/5973
03/30/03

Project 2 - Robot Design

For this second project, our robot from the first project was stripped down to the drive section and rebuilt with the new sensors required by our strategy.  The hardware design consists of the drive section, front bumper assembly, light tracking servo, handyboard cradle, and range dectection servo.

The drive section is roughly the bottom third of our robot("Bertha"), and is essentially a sturdy frame with the two drive motors secured inside.  Each motor drives both wheels on a side.  Gearing to the motors is such that the wheels turn slower, but with more power, giving Bertha more consistency to its movements.

The front bumper assembly has two fuctions; it feels for objects in front of Bertha, and it makes contact with the light bulbs to trigger them.  To sense objects in front, there are two free swinging bumpers held by a center piece that connects to the drive section.  Each bumper is held by a rubber band that keeps the bumper from swinging wildly about.  When the bumpers come it contact with an object, they depress slightly, depressing a touch sensor connected to the center piece.  After a run in which Bertha was forever running into things, we added two cross connectors to the bumpers.  This change allowed Bertha to know if it ran into an object at any point on the front.  For triggering the light bulbs, steel wool was affixed to the front bumper.

The light tracking servo is used to both seek and track a light source.  It consists of a servo braced in a lego frame, mounted onto the front of the drive section above the bumper assembly.  On the servo itself is a lego frame bracing three light sensors, one pointing forward and two pointing at slight angles away from center.  The center sensor is used largely for seeking the light, while the outer two are used only for tracking a light that was found previously.  The servo is mounted such that the center light sensor can point anywhere from 90 degrees to the left to 90 degrees to the right.

The handyboard cradle for Bertha is a bit of a quick fix setup.  Since the drive section is just wide enough to hold the handyboard, a front and back brace were placed so that the handyboard rests on the rear half of the drive section.  Gaps were left to enure access to the start and stop buttons, as well as the on/off switch.

The range detection servo sweeps the front area looking for buckets.  Again a lego frame holds the servo in place.  This frame was mounted above the drive section by building it's side walls up above the light servo and the handyboard cradle, with crossbeams across to connect to the frame.  On the servo is affixed a rangefinder which, like the light tracking servo, can sweep from 90 degrees left to 90 degrees right.  The rangefinder is partially protected from false readings from below by a pasteboard shield, taped to its sides and below.