Newsgroups: comp.robotics
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From: rstevew@armory.com (Richard Steven Walz)
Subject: Re: PWM DC motor control
Organization: The Armory
Date: Thu, 24 Mar 1994 10:04:50 GMT
Message-ID: <Cn5yo4.1As@armory.com>
References: <Mar18.181352.31507@acs.ucalgary.ca> <PJG.94Mar18132910@parint.esl.com>
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In article <PJG.94Mar18132910@parint.esl.com>,
Paul Gyugyi <pjg@parint.esl.com> wrote:
>In article <Mar18.181352.31507@acs.ucalgary.ca> morrow@cns8.cns.ucalgary.ca (Bill Morrow) writes:
>   Is anyone trying to actually vary the driving voltage to the motor,
>   using some feedback from shaft encoders? You know, just like they 
>   taught you in that control systems course. It seems to me that this
>   type of control system would be more efficient, responsive and cover
>   a wider range of motor speed.
>
>From what I understand, while the ratio of voltage to speed is fairly
>linear, the tourqe from a motor increases greatly with higher voltage.
>That is, for a given speed, you get more torque by using PWM at the
>max voltage than you do by having a constant, lower voltage.
>
>There's nothing to stop you from using a control loop and converting
>the output signal into a corresponding PWM signal. I did some work
>with LEGO models driven with gumbands in the drive train, and
>a basic control loop did wonders to improve the performance.
>| Paul Gyugyi                      scrabble...click...snap...  |
>| gyugyi@earthsea.stanford.edu     Paul_Gyugyi@smtp.esl.com    |
-------------------
And since not all of us have a course in control systems under our belts,
even if we do grasp the concept, can you tell us what algorithm you used to
keep the speed from dithering, and how many equational terms you needed, or
did you use a fuzzy application and what sets did you use?
-Steve Walz   rstevew@armory.com

