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Unread 22-01-2017, 11:01
AriMindell AriMindell is offline
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Re: Mecanum Drive control

Quote:
Originally Posted by TylerHarmon View Post
Sure, if you want to discuss it further we can. My main point is that the rollers on mecanum wheels...
... freely spin, which allows a robot to strafe, but results in inconsistent data when used with an encoder.
Ether posted the following code for determining robot position based on the wheel velocities of mecanum wheels in another thread:
Code:
FWD = r*(w1+w2+w3+w4)/4

STR = r*(w1-w2+w3-w4)/4

Wv  = (1/k)*(w1+w2-w3-w4)/4

r is wheel radius
k is |trackwidth/2| + |wheelbase/2|
w1,w2,w3,w4 are FL,BL,BR,&FR wheel speeds in rads/sec
Wv is robot clockwise rotation rate in radians per second
The implicit assumption is that the velocity vector applied to the robot by a mecanum wheel spinning at constant velocity is constant.

are you arguing that the velocity vector created by a mecanum wheel spinning at a constant velocity is not constant or predictable, therefore that equation provides an unreliable estimate of robot position?
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