[raphaelchang]

Starting in 2013, 846 has a been using a steering wheel for turning and a joystick for throttle. We tried out the idea after seeing 971 use a steering wheel setup. Having the turn and throttle components on separate controls allows us to drive straight and turn in place more easily, and it also allows better control of arc turning (turning while driving forwards/backwards).

We found this as the optimal driving scheme after experimenting with several other setups as well:
2011-2012 - Single joystick for forward and turn, forward and back motion for throttle, joystick twist for turn. This made arc turning difficult because both motions were controlled with one hand. Turning in general was also difficult because the twist was more sensitive and turning with the wrist was more difficult to control precisely.
Off-season - We also tried two other setups during off-season, tank drive and vector drive. Tank drive used two joysticks, one to control the left side and one to control the right side. This made the driving feel more natural, but it also made precise control difficult. Driving straight was difficult and precise turning speed was hard to control. Vector drive used the angle of the joystick to specify the direction of the robot and the magnitude to control the speed. The robot would turn automatically to face the angle pointed by the joystick and move forward at that speed. Although this field-centric setup made it easier to go the direction we wanted, it was difficult to control for tight manipulations.