Odom reset tape

Rebasing odometry on the field tapes

Another way you can use the field to get an accurate position of your robot is the field tapes. We can use these tapes to constrain the position of the robot on one axis per reset allowing us to keep an accurate robot position over the match.

Detecting the field tapes

There are several different ways that we can detect the field tapes. But to find the best one we have to consider the requirements of such a system. Some of the factors that will effect which solution that we choose are, distance per frame, the sensor detection area, and the sensor size.

Distance per frame

To calculate the distance that we will move per frame we will have to find the maximum possible speed that such a system will be required to sense at. The maximum speed for our first robot this year is about 45 in/s, be we would like to have a lot of margins to accommodate faster drives that we might make in the future so we will have this speed at 70 in/s. The frame time of each of the systems and the distance per frame are listed below.

• V5 Color Sensor
  • Update time - 10 ms
  • Max Distance per frame - 0.7 in
  • Max speed - 30 in/s
  • Size - 1in x 2 in
• Infrared Line sensor
  • Update time - 10 ms
  • Max Distance per frame - 0.7 in
  • Max speed - 70 in/s
  • Size - 3in x 3in
• Vision sensor
  • Update time - 50 ms
  • Max distance per frame - 3.5 in
  • Max speed - 70 in/s
  • Size - 4in x 4in

We chose the infrared line sensor because of its size and update speed. This combined with its own infrared emmiter will allow us to keep this compact package.

Differentiating between lines

We have a lot of ways to differentiate between tapes, including estimating the line angle or width to just getting the closest line. We will need to use a combonation of all of these methods because of the many lines that have the same slope around the field.