Hi.
I read in a 2018 thread that odrive maxes out at 75% of base speed. Is this still true?
For my project I am planning to use this motor: PROPDRIVE v2 5060 380KV with 2.6 kw of power.
With 36v its max rpm is around 13680, 75% of which is around 10000 rpm, which the max rpm I need.
At the moment I don’t need position control, just the speed control.
And the key point is, I need the motor to be able accelerate as fast as possible, with max current
Could you please tell me if odrive is well suited for this?
Thank you.
Yes they max out at about 75% voltage * kv, that way there is some overhead to prevent voltage spikes that would destroy the controller when decelerating, and it gives the PI controller a bit more leway since it can go a bit higher
Use a high resolution encoder and run the motor in current control mode (I think it might be called torque control?) and use input mode passthrough, then you can set the desired current to be your motor current max and let it rip
Or if you put it in velocity control mode, keep it input mode passthrough and set the gains really high
Thank you!
But I can’t seem to find in the docs a possibility to set the current directly in a torque control mode?
Also, the standard odrive encoder has a limit of 7500 rpm in the docs:
even though in the specs for the encoder it says that it can be 15k rpm with lower resolution?
Since I don’t precise position control, is it possible to use this encoder at lower resolution to achieve higher speeds?
Here is the link to the ODrive control modes, torque is at the very bottom of the page
If you set the torque constant as 1, setting the input torque will actually set the phase current
https://docs.odriverobotics.com/v/latest/control-modes.html#torque-control
Yeah you can use it at lower resolution, it just affects how much lag there is when it starts to rotate, in theory you can do it with just the hall effect sensors built into the motor but it won’t be as smooth when it starts
Curious, why is lower resolution causing a delay before motor starts to rotate? Is it a large one?
The higher resolution the encoder the more accurate the motor can begin to turn
No, that restriction is lifted with the new generation (ODrive Pro and S1), it can now achieve full modulation index, i.e. hit a no-load speed of 100% * bus voltage * Kv
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