The robot is made of the NXT brick (the robot’s “brain”) and Legos. The robot completes specific tasks (missions), which are also made of Legos. When we build the robot, we can not use string, tape, etc.
The robot we're currently using has three motors, two which power the wheels, and one which controls the attachments. We currently have 4 sensors - light, color, and ultrasonic,. The robot has 3 attachments.
In past years, we've had a lot of issues with consistency, so we perform consistency with our robot. We run two different consistency tests, a straight test and an L-test (ORTOP - Consistency Testing. For the straight test: First, we tape a sheet of paper on to the table, then we program the robot to move forward a certain distance and then stop. We use a pencil to mark where the robot stopped. Next, we measure how far apart from each other the marks on the paper are. For the L-test, the robot goes straight, makes a 90 degree turn, then straight again. We use a pencil to mark where the robot stops.
In past years, we started with a simple bot and made it work. This year, really wanted a robot built around the missions.
Here's what we've done thus far this year:
To start out the season, we began work on a 2011 Food Factor challenge by splitting up into groups of two. These groups of two then a planned and programmed a full robot game. Our coaches also set up a mock technical interview for each team. When we finished, each team member identified areas they felt they did well in, but also identified learning goals. We compared lists to match up people with certain learning goals to those that had identified that as a strength.
One of the overall team learning goals was advanced programming techniques. We worked on advanced programming techniques by using flow charts to plan out our robot game then converted them to programs. We also worked on nested switches, nested loops, data wires, and sensors. We created a lot of small programs including a program that used an ultrasonic sensor to detect when an obstacle was within a certain distance and then using that information to slow the motors down. We created another program using a color sensor and nested switches to detect colors and then say the name of the color.
Another team goal advanced building. We worked with gears and built a lot of different attachments and then played with them to learn what the strengths and weaknesses of each attachment was.
Finally, we started looking at this years robot game and decided on which missions we would like to attempt and what type of robot we would need to accomplish that. After that we then broke into groups to working on using gears to gear up and down and 4 wheel drive.
We've had several iterations of our robot design so far. First, it was unable to go over the barriers required to complete part of our mission so at this point we started looking into 4 wheel drive to cross the barriers. After we were able to get the robot over the barriers we realized the color sensor was too low and had to be adjusted in order to cross across the barriers. We came up with a design that will allow us to lock the color sensor into a higher position when we're ready to cross the barriers.
We've noticed some problems with turning using the 4WD, so we also explored a robot that can convert between 2WD and 4WD by moving a gear.
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