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Time constant/Dead time of SOLO UNO

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Forum 1
(@thetris93)
Active Member
Topic starter
 

Dear all,

 

I am currently building up a Simulink Model of my Hardware in order to optimize my control parameters for the speed and position loop. In order to have a sufficient transfer function I would like to assume something for the dead time of the SOLO UNO or in other words its time constant. Do you have any experiences about this?

Right now I'm assuming that the time constant of the SOLO UNO is 200 µs at a PWM frequency of 20kHz.

 

Thank you very much for your help!

 

TheTris93

 
Posted : 10/01/2022 10:38 am
SOLO Team
(@milad)
Illustrious Member Admin
 

Hi @thetris93,

if by "Time constant" you mean the execution rate or the Loop rate, below are the info for you:

Torque Mode: For SOLO UNO and MINI, The loop rate is synched with the PWM frequency, so for 20kHz of switching frequency, the controller loop rate is 50 microseconds for the Torque loop.

Speed and Position Mode:  For SOLO UNO and MINI, the loop rate is fixed at 2kHz independent from the switching frequency.

Now, regarding the data transfer rate if you are using USB or UART: 

  1. Each character ( byte)  is processed with a synched rate to the PWM frequency up to 30kHz, and above 30kHz PWM frequency the loop rate is fixed at 33micro seconds ( 1/30kHz), so it means if the PWM frequency is set at 40kHz, SOLO processes each UART/USB byte in 33 microseconds, subsequently for PWM frequency set at 20kHz, each character ( byte) is processed at 50 microseconds.
  2. The USB/UART packets for  SOLO are each are 10 bytes, which means to process a full packet, SOLO requires 10 iterations, so for instance at 20kHz each packet is processed at 500 microseconds, to increase this you can increase the PWM frequency up to 30kHz to have 330 microseconds for full packet processing speed.

Regarding the CANopen data transfer rate:

Each CAN packet is processed separately and at once, so it offers a much faster loop rate up to 5 to 10 times faster than USB and UART interface.

Let me know if you have other questions.

Regards
Milad

 

If you found the answers helpful and you could solve your problems, please kindly verify here to help others in the future.

 
Posted : 10/01/2022 11:03 am
Forum 1
(@thetris93)
Active Member
Topic starter
 

@milad 

 

Hi Milad!

 

This really helped me a lot! Thank you very much for your helping hand.

 

Best regards,

 

TheTris93

 
Posted : 11/01/2022 8:23 am
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