The Designs That Wouldn't Work
The Initial Design
Using a Lego Robotics book, the group initially constructed the basic version of "Trusty."
Trusty was designed from The Unofficial Guide to LEGO Mindstorms Robots by Jonathan B
Knudsen. Knudsen's Trusty consisted of a single light sensor mounted at the end of a beam which
extended from a three wheeled vehicle.
There are a few obvious problems with this version of Trusty. The most obvious is that there is only
a single sensor. With one sensor, it is harder for the robot to correct itself, ie once it does not
see the line, it is totally lost. Another problem with Simple Trusty is the sensor placement. Because
it is placed on an extended beam, the sensor is far away from the axis of rotation. This causes a larger
turning radius and a less accurate robot. Finally, the sensor is high off the line. The farther away
the sensor is from what it is trying to read, the less it will work. (Instructions on building this version
of Trusty can be found in Chapter 3).
The Tread Design
Initially, it was identified that the three-wheeled version of Trusty had a large turning radius. Ideas
for a new design were immediately begun, and it was suggested that a treaded version of the robot may be
more accurate. The Treaded Trusty was built using the main body from Simple Trusty, but removed the wheels
and replaced them with tank treads. Although this solved the turning problem, the treads forced the sensors
to be held high above the ground. When the sensors are not very close to the line, they don't pick up the
color change as easily. In the end, the sensors were too high to detect the line, and Treaded Trusty was
eliminated as a Trusty choice.
Simple Trusty, Version 2.0
After discarding Treaded Trusty, the Trusty from the previous group was constructed. This trusty had a
three sensor configuration instead of only a single sensor. Although it was a good starting point, a
problem arose when one night, while testing code, the robot became lost. As it tried to look for the line
as it was programmed to do, it began to shake and literally fell apart. It was decided that, although this
Trusty was going in the right direction, it was not durable enough and needed to be upgraded.
You can learn more about Trusty 2.0
at the previous team's websight by clicking here.
Trusty Version 3.0
Trusty Version 3.0 was very similar to Version 2.0 with exception to the fact that it was strengthened in the back
(where the previous Trusty fell apart the most) with extra legos. This Trusty held up better, but still had the
wide turning radius problem, which needed to be solved. In order to do this, the team had to come up with a way
to get four wheels on Trusty. The problem? There was only room for three motors...
How did the team solve the problem? What is the final Trusty like?
Click here to find out!