Quote:
Originally Posted by AriMindell
So I agree with this assertion for trying to determine the position of the robot using encoders, but what I meant was using encoders to ensure that all of the motors are actually spinning the same speed (rather than just recieving the same voltage) for this, I think encoders can be adequate, since slipping does not come into play between the motor and the wheel, only later.
In other words, there is very little error in the encoder reading of the wheel angle relative to the robot (maybe some backlash in the gearbox) however I agree that there is a large amount of error in the encoder reading of the robot position relative to the field. Correct me if I'm wrong, but I think that since we are looking to use the first one, encoders are acceptable.
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Ah, I see what you mean. I think that could work; if you are only looking at the rotations per wheel and not necessarily how far the wheel drives on the floor, you could get more useful data.
However, if your goal is to drive straight, I would suggest using a gyroscope, because even if you drive all 4 (or 8?) mecanums at the same RPM, they still will likely not operate identically to each other because of various conditions like the consistency of the floor that could cause the rollers to spin more/less.
All that said, the main use of encoders is to see how far a spinning motor or axel has moved (and at what speed), so I still can't recommend using encoders with mecanums because they simply, by design, do not give very useful data. Even if you just looked at how far they wheels turned, that data, while perhaps being accurate, would not be very useful.