TMS320F28069: InstaSpin Motion Position Controller delay, lab13a

The reference takes effect when you call STPOSCTL_run(). Is there some code between when you set the reference and when you call the position controller run function?

Sean

Thank for replay Sean, I use lab13a with small modification, where instead of setting 0 as reference  in to position controller I pass variable target_position, and there is delay between changes of value "target_position" and motor position changes. Here is my position controller run function:

void ST_runPosCtl(ST_Handle handle, CTRL_Handle ctrlHandle)
{
    ST_Obj *stObj = (ST_Obj *)handle;

    // provide the updated references to the SpinTAC Position Control
    STPOSCTL_setPositionReference_mrev(stObj->posCtlHandle, target_position);
    STPOSCTL_setVelocityReference(stObj->posCtlHandle, 0);
    STPOSCTL_setAccelerationReference(stObj->posCtlHandle, 0);
    // provide the feedback to the SpinTAC Position Control
    STPOSCTL_setPositionFeedback_mrev(stObj->posCtlHandle, STPOSCONV_getPosition_mrev(stObj->posConvHandle));

    // Run SpinTAC Position Control
    STPOSCTL_run(stObj->posCtlHandle);

    // Provide SpinTAC Position Control Torque Output to the FOC
    CTRL_setIq_ref_pu(ctrlHandle, STPOSCTL_getTorqueReference(stObj->posCtlHandle));

}

Hi Harry, sorry for the delay in response. STPOSCTL depends on the reference and feedback, so those two API need to be run before STPOSCTL_run(). Can you try positioning these such that their calls are immediately before the SpicTAC position control function? Also, what's the SpinTAC bandwidth? You can try increasing this to decrease time from update to reaction, but it could also come at the cost of stability

Sean

Hi Sean, here is my SpinTAC loop in mainISR:

// Run the SpinTAC Components
  if(stCnt++ >= ISR_TICKS_PER_SPINTAC_TICK)
  {
      {
          ST_Obj *stObj = (ST_Obj *)stHandle;

          // get the electrical angle from the ENC module
          ////STPOSCONV_setElecAngle_erev(stObj->posConvHandle, ENC_getElecAngle(encHandle));
          STPOSCONV_setElecAngle_erev(stObj->posConvHandle, elecAngle);

          if(USER_MOTOR_TYPE ==  MOTOR_Type_Induction) {
            // The CurrentVector feedback is only needed for ACIM
            // get the vector of the direct/quadrature current input vector values from CTRL
            STPOSCONV_setCurrentVector(stObj->posConvHandle, CTRL_getIdq_in_addr(ctrlHandle));
          }

          // run the SpinTAC Position Converter
          STPOSCONV_run(stObj->posConvHandle);

          if(USER_MOTOR_TYPE ==  MOTOR_Type_Induction) {
            // The Slip Velocity is only needed for ACIM
            // update the slip velocity in electrical angle per second, Q24
            SLIP_setSlipVelocity(slipHandle, STPOSCONV_getSlipVelocity(stObj->posConvHandle));
          }
      }
      ST_runPosCtl(stHandle, ctrlHandle);
      stCnt = 1;
  }

as you can see STPOSCONV_run() and ST_runPosCtl() execute at same rate but I still have delay on system response to position I set in  ST_runPosCtl()

here is chart where system run with bandwidth 20 rad/s 

It is plotted at 100 Hz and delay between commanded position(blue line) and encoder position changes(orange line) is about 0.08 seconds.

when I increase bandwidth to 30 rad/s the motors become noisy but it still holds position and delay is 0.05 seconds:

I can't increase bandwidth more than 30 rad/s because it starts osculating.

Hi Harry, any update here? I will mark this closed but feel free to reject the answer and re-open the thread for more comment

Sean