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Quote:
Originally posted by GregT
I'm talking about a robot with a 360 degree freedom of movement, instantly - no turning. From standing still it can go any direction it feels like.
Greg
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This is also known as "holonomic" motion.
The long technical name we used for our 'Kiwi' drive system was an 'omnidirectional holonomic platform with zero kinematic redundancy'.
Basically meaning it could drive in any direction (omnidirectional) like a swerve/crab drivetrain as well as do this with instant acceleration in any direction (holonomic) i.e. no need to turn the wheels like on a swerve/crab drive all while having no wheel drive in the same vector plane (zero kinematic redundancy) i.e. three wheels 120 degrees so no tow drive wheels produce motion in the same direction.
Ideally, the Kiwi (a true three degree of freedom drivetrain) can drive in any direction (x & y translational velocity) while rotating around its axis (rotational velocity). This is what a crab/swerve drive can not do. They can drive in any direction. And they can rotate on their axis. But they can't do it at the same time.
Now, what does this mean in competitions? 2002 was the perfect year for the Kiwi. We had three matched motors (the drills), a flat playing field, and a great deal of research ahead of time. A well constructed crab/swerve will give you nearly equal mobility with mechanically guaranteed straight-line motion (if done correctly, of course). Still, it won't give you the fluid motion and overall 'coolness' of holonomic motion.
Adam