Encoders for Autonomous vs. Teleop

[keericks]

I've seen plenty of posts for using wheel encoders to control velocity, distance, turning, etc. What I'm struggling to fully understand is how/why would position sensors be used during teleop mode? Not looking for code examples here, just a discussion of how/why so my students can start looking for ways to implement them if necessary.

[Alan Anderson]

We've used wheel encoders during teleop for three things I can think of.

First was a way to make sure the robot goes straight when it's not being commanded to turn. On a robot with two traction wheels and two omniwheels, that made the driver's job a bit easier

For the Rack 'n' Roll game, we had something the drivers dubbed "Bulldog mode". It was intended for the robot to actively hold its ground while the operator scored the game pieces. When enabled, the robot would apply power to keep the wheels where they were. The drive team didn't get a lot of practice with it, but it definitely helped.

Most recently we used wheel speed feedback to implement a simple traction control algorithm for Lunacy. Keeping the wheels from slipping made a noticeable difference in how quickly the robot could accelerate.