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Acceleration in lab 13b

Andreas Banksell
Prodigy 40 points


Hello,

I'm running lab13b trying to run a set number of turns on my motor and then stop, and to do this as quickly as possible.

I've tested to run my motor without load and with load and the acceleration is the same, so I belive there to be a limitation in the software.

I found the thread "!InstaSPIN acceleration more than 500krpm/s2" and started to look at the trajectory parts of ctrlQEP, but the lab in the acc-thread is not the same as I run.

So my question is: is it possible to override the trajectory calculation during acceleration in lab 13b and what parameter would I then be overriding? refValue? fbackValue?


Or is there another way to reach my goal? Is it possible to accelerate using torque mode and then, mid movement enable spintac positioning for a controlled stop at the right angle?

Best regards

Andreas

  • 0
    Guru 12800 points
    Andreas,

    Have you been adjusting the velocity, acceleration, deceleration, and jerk limits that are made available in lab 13b? These limits are used to allow the profile to change mush more rapidly.

    For position control, I would not recommend overriding the traj calculation since it is much more complicated than velocity.
  • 0 in reply to Adam D. Reynolds
    Prodigy 40 points

    Hi Adam,

    Yes, I've maxed Acc (iq24-120), Jerk (iQ20-2000) and set the curvetype to ST_MOVE_CUR_TRAP.

    I've sampled some of the variables in CTRL_runOnLine and compared them with my mechanical position and found that

    refValue (calculated by = TRAJ_getIntValue(obj->trajHandle_Id) + CTRL_getId_ref_pu(handle); )  increases as my velocity rises, but it also seem to dampen the velocity later in my movement. 

    I'm curious about what would happen if I override this value in the beginning of my movement (say the first 10 degrees of the motor rotation) with the value that I sample at 10 degrees rotation. What do you think? Should I try? :)

    If overriding the trajectory is a bad idea, what would you suggest as an alternative?

    Andreas

  • 0 in reply to Andreas Banksell
    Guru 12800 points
    Did you max those out by setting IQ24 - 120 and IQ20 - 2000 as the pu values or was that in krpm?

    I'm surprised that your Id reference value is changing. That should really be 0 for pmsm motors or a constant for acim motors.

    You could override it but I don't think it would help the motor spin up any faster.