[Al Skierkiewicz]

Crab steering (this is the term used for swerve since it emulates the way a crab walks.) is not needed for every game. For this reason, we do not decide which drive train we will use until after the game has been analyzed. This year's game did not require crab steering. When maneuverability is an absolute must or when the robot is required to move sideways to pick up or retrieve then crab is a possibility. The design of the drive modules will determine the weight and individual transmissions can double the weight if similarly sized gears as tank designs are used. Since each tranny carries less load, the components can be lighter.
Of prime importance is the ability to control the steering. Therefore a good feedback system and software are needed. The operator control is another factor that needs thought to make driving easy. Designs can have other problems that vary with the design. How will you get wiring down into the module, will the module contain the motor or will all the drive components be outside the rotating device. What is the game going to require as to the base dimension and what is needed for retrieval of game objects. You may find that a design that requires 8 or 10 in. sq. will not allow space between the modules for other robot components. Finally, How do you get to Carnegie Hall? Practice, Practice, Practice. Even the best crab drive system won't get you anywhere if your drivers can't control the robot well enough to play the game.