Thread: Motor Bias
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Unread 31-10-2005, 13:38
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Mike Betts Mike Betts is offline
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Re: Motor Bias

Quote:
Originally Posted by gshosford
We changed the program to lower the maximum pwm to each motor. As I recall we calibrated the Victors before we started our test. We put the robot up on blocks to check wheel rotation so the wheels were not in contact with the floor. With a PWM of 127 + 32 to one Victor and 127 - 32 to the other Victor there was a significant difference in the two motor speeds. When we moved the joystick to the opposite extreme, the motor that had been the faster of the two became the slower of the two and the one that had been the slower of the two became the faster of the two. The observations are qualitative, but there were significant differences between CW and CCW motor speeds.
The effect that you saw was discussed in length in this thread. We verified Jim Rickertsen's data (see the attached plot) and were able to linearize the CIM speed to PWM command.

Note that this is a system issue. I never determined if it was the IFI controller or Victor issue and did not care... The bottom line is that it is NOT the CIM.

Regards,

Mike
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Mike Betts

Alumnus, Team 3518, Panthrobots, 2011
Alumnus, Team 177, Bobcat Robotics, 1995 - 2010
LRI, Connecticut Regional, 2007-2010
LRI, WPI Regional, 2009 - 2010
RI, South Florida Regional, 2012 - 2013

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