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Torque Control Mode

Hi 
In Dyno operations, they used to say Speed mode and Torque mode. Speed mode - controls the speed and I used PID to model this. I am confused on how to model torque mode. 
Do we need a complex feedback loop for the Torque mode ? Can't we just use the controls toolkit to model it ?  If so what all the inputs that I need to have. 
 
Any advice will be of great help. 
 
  • You clearly need a feedback loop, but it might be as simple as a PID.
    You feedback your velocity and compare with the desired velocity and feed the error into a PID controller.
    I don't understand why you needed a controller for the speed mode or how you implemented that. If you have a desired speed profile you just feed that into a MOTION statement.
    Without you describing the model more in detail, I can't help you more.
  • I have a part-1 spinning at RPM A. And part-2 will start with RPM A and it ll start to decelerate (I have the complete speed curve for part 2) . For this   I did the same as u mentioned. I used the torque element to give the speed error, speed error dot with PI gains. When there is some speed difference between the two parts, I will try to engage these two and I am interested in finding the peak torque due to this engagement. 
     
    If I use motion, then the peak torque is extremely higher. I wasn't still getting the same kind of torque peak thats being measured. Then I googled about feedback loops in dyno, came across some feedback loops which might help me solve the problem.
    I am attaching an image of the measured values.  My first question was, why isn't the torque in the deceleration phase not shown in the measurement. 
     
    Test
  • So you already are using torque control.  That was your original question, right?
    Using speed control, you would have a motion driving with exact speed profile data. Then you have to deactivate that motion at the right time and activate your clutch element.
  • Yes.I deactivated the motion element.  Using the torque control gave similar kind of plot. If I were to measure the torques , I would just select the torque element and measure it which shows the deceleration phase torque in my calculation. But the stand measurement did not show that. This is something that confuses me. If you had similar problems, any suggestions will be of fruitful help to me. I have very less knowledge about dyno.