Position based on RPM?

Hi All,
I’m trying to develop a system that positions its self based on a measured rpm.

I have been looking at using Parts as follows.

Pololu 2344 - Generic Linear Actuator: 4" Stroke, 12V, 1.5"/s
Pololu 1394 - Pololu Jrk 21v3 USB Motor Controller with Feedback (Fully Assembled)

Is possible to position the Actuator from 0” to 4” by detecting the rpm of a rotating shaft (electric motor) between 0rpm to 6000rpm.
The rotating shaft sensor measures four pulses per revolution, but we could use a different feedback device.

When the shaft is still, actuator position should be at 0”
When the shaft speed is 3000rpm, actuator position should be at 2”
When the shaft speed is 6000rpm, actuator position should be at 4”

Any idea’s would be greatly appreciated.


I do not know of any motor controllers that can directly accept encoder inputs and process them to do position control in the way you described. However, you should be able to use a separate microcontroller, like an Arduino or Arduino-compatible A-Star 32U4 Programable Controller, to process the encoder inputs. Then, it can send TTL Serial signals to the jrk to control the actuator.

By the way, the actuator that you mentioned is discontinued and does not have a feedback potentiometer. If you want to do closed-loop position control, you might consider the Concentric LACT4P-12V-5 Linear Actuator with Feedback instead. I suggest reading the “Using a jrk motor controller with a linear actuator with feedback” section of the actuator’s product page to get an idea of how to set up the jrk for use with the actuator.