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POST No. 2408055
MX64 velocity and PID
2021-06-15 17:53:08 bluegoat@boston

Hi, 


there is a question, I know we can setting velocity in  MX64, we also can setting GO position. also there is a PID control loop inside of the motor.


so if I get velocity=70,  and I want to go to a position such as 180 degree, 

the velocity will vary during the Go action(pid control)?    

if vecloity will vary, what is meaning about seting velocity? 


thanks!!



2021-06-15 17:53:08
bluegoat@boston
2021-06-16 10:28:47 Will Son

Hi,


For MX-64, you can use two different firmwares for Protocol 1.0 and Protocol 2.0.

I'll assume that you are using Protocol 2.0.

In case of setting your DYNAMIXEL to Position Control Mode, the Goal Velocity(104) is not used.


On the other hand, the Profile Velocity(112) and the Profile Acceleration(108) is applied to generate the trajectory profile.

DYNAMIXEL in Position / Extended Position Control mode will use the Profile Velocity value to limit the maximum RPM.


Thank you.

2021-06-16 10:28:47
willson
2021-06-16 10:52:58 robfei

Hi,Willson


Thanks for your replay. 


so as my understand:

in the Position control mode,  the velocity what I set is only to limit the Maxinmun RPM.  It is right?


Thanks!

2021-06-16 10:52:58
bluegoat@boston
2021-06-18 15:49:12 Will Son

In Position Control Mode, the Goal Velocity does not govern the max RPM.

Please see below diagram which describes the Position Controller, and you can see that the Profile Acceleration and the Profile Velocity are used instead of Goal Velocity.

You can use the Profile Velocity to limit the maximum RPM.


Or you could also use the Velocity Limit to limit the max RPM, but since this value is saved in the EEPROM, you won't be able to modify this while torque is turned on.


 

2021-06-18 15:49:12
willson