Team 2471 swerve drives

[Bryce2471]

Could you provide more detail about your software? e.g. Does it have 3 independent degrees of freedom (X, Y, and rotate) or just X and Y?

Yes. It has full 2D motion capabilities. All of these should be visible in the posted video.

What does the Driver Interface look like? Is it field-centric or robot-centric? etc.

The software is new. We have never programmed a swerve robot before so we kept it simple with a robot-centric driving system.
The code is made up of two, somewhat simple parts right now. First, the left analog stick input gives an X-Y heading. That vector is directly applied to each wheel. This gives us our translation or strafing ability. Next, the X component of the right analog input gives a turning value. This value is set as the length of a vector on each wheel for orienting the robot. The angle of this vector is defined as being perpendicular to a line between the wheel and the the center of robot rotation.
Then, one problem is that each wheel has two vectors that it is supposed to accomplish. The solution is simple: you just add the two vectors together. This presents a second problem. If you try to turn at full power and drive at full power at the same time, each wheel will try to drive at >100% power. This is solved by dividing each wheel's power by the power of the highest power wheel if that is greater than 100%.

Was the problem related to the gyro?

No,
This code, as I mentioned earlier works quite well, but it is somewhat difficult to drive. So before the off-season ends, we will be implementing a field-centric drive code. To get our sense of bearing, we will be using both gyro and compass sensors. To filter these inputs together we considered using a Kalman filter, but we decided it was not a good solution because it has a lot of tuning involved as well as not having a lot of information available on the details of how to tune them. We have decided to implement our own filter that is much more simple and gets directly to the solution. It essentially works by taking the height of the compass sensor on a graph and applying the curve of the gyro input to that.
We had a problem in the beginning: a small syntax error that caused a lot of very odd outputs and symptoms.