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dolpre
Joined: 18 Jan 2008
Posts: 103
Helped: 36
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 05 Apr 2008 15:29 Re: Analog PID control for DC motor position |
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Hi FvM,
i understand that with a gear, the speed will reduce while the torque will increase.
May i know what is the relationship between a gear ratio, N with torque and speed?
In my case, i found that speed_gear = speed/N but the torque_gear != torque*N.
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| Ke = Kt related to the reduced shaft would also be scaled. |
may i know how to scaled it? Is it just multiply or divide it by N?
How if i found the transfer function of the motor without gear, is Kt/(tau*s+1) and want to convert it to the transfer function of motor with gear ratio of N?
Thanks in advance...
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FvM
Joined: 22 Jan 2008
Posts: 2315
Helped: 385
Location: Bochum, Germany
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| 05 Apr 2008 15:56 Re: Analog PID control for DC motor position |
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| For an ideal gear, Ke and Kt would be multiplied with N. If you observe a torque below the theoretical value, it could be due to gear efficiency below 1, I would expect 60 to 90 % depending on gear ratio.
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dolpre
Joined: 18 Jan 2008
Posts: 103
Helped: 36
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| 05 Apr 2008 17:35 Re: Analog PID control for DC motor position |
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| i calculated, the gear efficiency is 73%, so for this non-ideal gear, the Ke and Kt will be multiply by N*0.73 right?
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SHESHAN
Joined: 23 Apr 2008
Posts: 1
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| 23 Apr 2008 0:48 Re: Analog PID control for DC motor position |
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| thanks
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baonguyenpro
Joined: 13 Oct 2006
Posts: 64
Helped: 2
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| 28 Apr 2008 8:10 Re: Analog PID control for DC motor position |
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| With MCU for Automotive like MPC5554, DC motor controlling is specified by eTPU (Enhanced Time Processing Unit), Freescale developed the library for it. You just use the APIs to build your application. It's very convenient.
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