Mecanum Question about strafing.

[wireties]

Originally Posted by SeafordVikingR

Yes, the wheels are in the "X" formation. What happens is, it strafes but as if it's on a curve rather than strafing straight left and right.

Your motors and/or transmissions are not producing exactly the same wheel speed and/or your weight is not properly distributed. This is expected. If it strafed perfectly you would be lucky. You need encoders for each wheel or need to characterize the performance of each motor/transmission/wheel and account for this in your code. I'm not sure how a gyro would help you - that would be a tricky algorithm.

HTH

[xXhunter47Xx]

Well we coded in labview so that might have been the reason why it was so easy for us. You are right though wireties, from messing with mecanum since day 1 of build season we realized that strafing perfectly is not a thing. We can get very close but it wouldn't work.

[wireties]

Originally Posted by xXhunter47Xx

Well we coded in labview so that might have been the reason why it was so easy for us. You are right though wireties, from messing with mecanum since day 1 of build season we realized that strafing perfectly is not a thing. We can get very close but it wouldn't work.

Yeah, most people miss the fact that the OEM says the CIM motor curves can be +/- 10% (at least at the free speed point).

[SeafordVikingR]

Thank you all for the responses. We did attempt to play with the gyro, but with no success. However! We realized that the wheels weren't moving in the right direction when they were strafing. What we had were the 2 front wheels moving in the same direction and and the 2 back wheels moving in the opposite direction. What we really needed were the opposite wheels, top left & bottom right, to be moving in the same direction. So when we figured that out all we did was switch the pwms in labview and now it strafes beautifully!

[dellagd]

Originally Posted by SeafordVikingR

Thank you all for the responses. We did attempt to play with the gyro, but with no success. However! We realized that the wheels weren't moving in the right direction when they were strafing. What we had were the 2 front wheels moving in the same direction and and the 2 back wheels moving in the opposite direction. What we really needed were the opposite wheels, top left & bottom right, to be moving in the same direction. So when we figured that out all we did was switch the pwms in labview and now it strafes beautifully!

Just curious, did you have the wheels incorrectly selected in the code? (For example, Front right and Back right were swapped in the code)

[SeafordVikingR]

See the thing is, the defaulted mecanum code had each motor set to a pwm already, but that's also where the problem was for us. A simple switch of the pwms in the code fixed it up nicely, though.