• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 83 subscribers
  • Views 1296 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Brushed DC Motor? Instaspin Motion Position control

Alan Grimmer
Intellectual 290 points
Other Parts Discussed in Thread: CONTROLSUITE

Is there a way I can use the InstaSpin-Motion Position control and link it to a DC motor with encoder? 

  • 0
    TI__Guru** 118000 points
    Alan,
    You certainly could use the IS-MOTION SpinTAC components to do position control and provide a torque reference output. You would obviously need to make major changes to a standard lab:
    - analog sense will be very different
    - FAST not required
    - forward control from the torque reference will be changed considerably

    You would be on your own for this.

    I've forwarded to Adam @ LineStream to see if he wants to comment on best path forward.
  • 0 in reply to ChrisClearman
    Intellectual 290 points
    Hi Chris,

    Thanks for the quick response. Just to check I'm on the same page

    - Analog sense would use the same hardware, you just measure 2 phase current's and voltages and select one that's conducting based on motor direction and work out torque

    - FAST would be replaced with encoder

    - Forward control is the formula to convert the torque command into a PWM output ?

    Would i be able to use the measure resistance function with the DC Motor? Or would i have to write a new one that's not in protected rom ?

    Cheers,
    Alan
  • 0 in reply to Alan Grimmer
    TI__Guru** 109730 points

    Forward control often output voltage command which will be converted to pwm duty.

    You can not use the Rs calculation function of FAST to measure DC motor resistance directly, because the PWM mode is different.

  • 0 in reply to Alan Grimmer
    TI__Guru** 118000 points
    - in most brush DC applications you would only measure DC bus and Vbus
    - correct, FAST serves no purpose with brushed + encoder
    - forward control is the application of voltage to the motor, typically through PWM modulation, with that modulation % determined by required voltage as demanded by the torque/current controller. Torque may be commanded to facilitate reaching a desired velocity and/or position (outer loops)

    as Yanming noted, motor ID / RsRecal / RsOnline would not work for a brushed DC motor

    DC motors don't typically require a DSP / high end MCU like C2000 to control, so there aren't many examples. Here is one, but it's open loop (no encoders)
    C:\ti\controlSUITE\development_kits\DRV8412-C2-KIT_v131\2xDC_Motor
  • 0 in reply to ChrisClearman
    Guru 12800 points

    I see no reason why it wouldn't work.  As Chris & others have said, it would be a simple matter of changing the torque side of the motor control.

  • 0 in reply to Adam D. Reynolds
    Intellectual 290 points
    Cheers for your answers guys i got this going today, as you mentioned spintac just outputs a torque and i feed it into my DC motor controller loop and its working well so far.
    I maanged to correctly measure the current aswell, it took abit of trail and error but i got it playing nice.