Days 1 - 7
Days 8 - 16
Days 17 - 27
Days 28 - 34
Days 35 - 41
The day of the competition - I did two runs, the closest I came to a cone was about 15 yards (from Cone 3).
I had a bug in my NMEA (GPS) decoding state machine. The robot thought the cone was in China. In the US, longitude is always negative (-68 = Maine, -123 = California ). I forgot the negative multiplier in the code. The robot was constantly navigating towards China. Unfortunately, my GPS does not work at all in the house, so I did all of my GPS testing via simulation (hard coding constants in the state machine. I had always correctly encoded the longitude constant with a negative sign, so I never realized the bug until I did more outdoor testing at the event.
The robot is now correctly navigating to GPS coordinates (here in the US). I am currently investigating another bug that causes the robot to miss waypoints in its internal map. This bug has been impossible to find without telemetry. Today I added a Bluetooth modem to the robot.
What did work well on the robot was the ultrasonic sensors and software along with the closed loop speed control and motor control in general. The robot regulated its speed on concrete and only had minor issues in tall grass. Towards the end of the day, the battery was going dead so it got stuck a lot towards the end of the day. I definitely need to add the Integral portion of the PI controller. When the robot would go into tall grass sometimes it would stall for a second and then start running. The Integral component will fix that.
The Ultrasonic system worked very well. I never had any issues with bushes that were eating other robots. This was sue to the two back sensors being aimed up. The two back sensors see the tops of the bushes, much easier to see than the trunk or lower portions of the bushes.
I do need to consider adding breaks to the robot. Even if the sensors detected an object, sometimes the robot would still hit it by simply coasting into it. There was also a problem with object that were too close. I think the MB1000's cannot see objects that are too close.
Thinks still left to do on the robot:
1) Fix the map bug
2) Finish the Raspberry PI vision system
3) Layout a board to cleanup the wiring mess
4) Integrate the power supplies
5) reconfigure the mechanical robot to be smaller