TMS320F28069M: speed regulation

Charlie Allan

Part Number: TMS320F28069M
Other Parts Discussed in Thread: MOTORWARE

I am running a 28069M controller using Motorware lab05f which allows you to use either the PI speed regulator or the spinTACH regulator. Both work as advertised, however I have noticed a lag on speed change when using the spinTACH speed controller. When the speed target is changed, say from 6krpm to -6krpm, there is a lag prior to the motor beginning to decelerate toward the new target. Is there a way to fix this lag?

Also, I have noticed, again with the spinTACH controller, that when the BW is low, say 10 and a load is applied to the motor such that it slows down from the target rpm, when the load is released, the motor overshoots the target speed temporarily and then settles back to the target speed. Is there a way to fix this "windup"?

over 4 years ago

0 Charlie Allan over 4 years ago

Intellectual 960 points

Will someone please answer this question?

0 Yanming Luo over 4 years ago in reply to Charlie Allan

TI__Guru** 115500 points

You might implement the classic PI controller if you only need speed close loop control, not a position or motion control, and add an Integral windup in the PI controller.

0 Charlie Allan over 4 years ago in reply to Yanming Luo

Intellectual 960 points

I'm planning on using spintach speed control. Do you have a solution for that, not pi?

0 Yanming Luo over 4 years ago in reply to Charlie Allan

TI__Guru** 115500 points

All of the instaspin examples are included in motorWare that should have a lab about speed control with spinTAC. There is no special solution as you want, you might tune the control bandwidth of the spinTAC speed controller in the example lab according to your system.

0 Charlie Allan over 4 years ago in reply to Yanming Luo

Intellectual 960 points

I am using a lab that demonstrates spinTAC speed control. This is what I'm having issues with. There is a windup issue and a speed overshoot issue. How can I fix these issues. I have tuned the lab for a no-load device (Tenik motor from TI). Please investigate and help me.

Thanks!

0 Yanming Luo over 4 years ago in reply to Charlie Allan

TI__Guru** 115500 points

You might set the right USER_MOTOR_MAX_CURRENT according to the motor or your system that should limit the maximum torque current, and tune the USER_SYSTEM_BANDWIDTH as well.

For spinTAC, must make sure that the USER_SYSTEM_INERTIA and USER_SYSTEM_FRICTION are identified correctly.

0 Charlie Allan over 4 years ago in reply to Yanming Luo

Intellectual 960 points

You might set the right USER_MOTOR_MAX_CURRENT according to the motor or your system that should limit the maximum torque current, and tune the USER_SYSTEM_BANDWIDTH as well:

I have set the maximum current to 3A because I'm running unloaded for test. The max motor current is 7A.

For spinTAC, must make sure that the USER_SYSTEM_INERTIA and USER_SYSTEM_FRICTION are identified correctly.

I have run the lab that measures inertia and friction and put them in the user file. I still have the same problem.

Any other ideas how to fix the speed overshoot and windup?

0 Charlie Allan over 4 years ago in reply to Charlie Allan

Intellectual 960 points

Does this part have bugs in the ROM spinTAC firmware? Seems like that may be the problem. Should I be focused on a PI regulator because of these bugs? The PI regulator was the first thing you suggested. I have noticed that you are not selling spintac in any of your new chips. Why not?

0 Yanming Luo over 4 years ago in reply to Charlie Allan

TI__Guru** 115500 points

No such bug as you mentioned if the motor parameters are correct and you select the right USER_SYSTEM_BANDWIDTH according to your system. If you need a very fast response, you might implement classic PI that could be enough.

SpinTAC is just supported for F2805xM and F2806xM in motorWare and is not supported for newer C2000 controllers in motorControl SDK till now.

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TMS320F28069M: speed regulation