Motor driver or controller for minimum latency


My application is force feedback (haptics), which requires small latencies, ideally less than 1 ms between the reading of position encoder and the change in the output voltage (or current with a current driver). The set value is produced by a dsPIC microcontroller that can generate PWM signals as well as UART communication. In this context, is it better to use a driver (like the MC33926 or VNH5019 Motor Driver Carrier or 18v15) than a controller (like the 18v7)?

Sounds like you want a driver.

You are asking if it is better to go:
(microcontroller dealing with position encoder)—>PC/USB—> 18v7 controller

(microcontroller dealing with position encoder)—>motor driver.

The second seems much better for a fast response, assuming you have the opportunity to modify the code on your dsPIC microcontroller.

Did I miss something?

I program the dsPIC microcontroller. In your terms, my question would be:

(microcontroller dealing with position encoder)—serial—>18v7 controller
(microcontroller dealing with position encoder)—PWM—>motor driver.

I don’t remember now why I wondered about that, as the answer seems obvious.

Very fair, but it’s good to ask the question.

I see now that my terms were off a little too, since I was forgetting you don’t need the PC as an intermediary of the serial commands :).

But, yeah, you’ll have more control locally with your microcontroller controller, and it is more than capable.