I like the module concept. Swerve is complex and many modes of failure . With independent modules if something goes wrong don't fix it on the bot. Remove the module and replace it. Fix it later. We can remove a module and have the new one installed in less than 10 Minutes. How fast can you remove one of you modules?
Yes, you can use a quadrature encoder with indexing for the steering but , why not use an absolute encoder? The C-rio only has 4 4x encoders. Why not save them for velocity needs? I believe the code is cleaner with absolutes.
You mention that you are not doing least distance calculations for steering angle. A properly coded least distance algorithm will not allow the wheels to be in a conflicting position. There is always a smooth transition from current position to the new set points. It also makes the steering much more responsive.
If you using window motors, I hope you have removed the locking pins and are using victors.
We have not found that multi-speed is needed. It also is 1 more degree of freedom for the driver to have to master.
Field centric control? From our experimentation I do not believe there is an affordable gyro or INU that can remain accurate over the time frame of tele op. However we will have a gyro on the bot for 2012 to assist with autonomous navigation. The one problem with swerve is the robot doesn't like to go straight with dead reckoning for very far.
Why go thru the pain and suffering of swerve development? Because it is hard. It's amazing how the stress of swerve development has made our students and team grow intellectually and from and organization perspective. Also , it was pure joy when a tank bot came flying at us from across the field and our driver executed the side slip move. We also can have our way with mecanum bots.
Do you have a 3d model of the module that you could post. This is ours let's see yours.
http://wiki.team1640.com/index.php?t...II_Drive_Train