Linear actuator resolution


I’m looking to use the linear actuator with feedback (#2311) with the Jrk 21v3 as suggested on the website.
What is the resolution of the linear actuator and can the software allow for movements in the sub-millimeter range? I think it has to do with potentiometer voltage, but I have no electronic background.
Thank you very much for your help.



I cannot give you a definitive answer because it in part depends on how good your PID constants are, but 1 mm on that actuator corresponds to 16 counts of the jrk’s feedback variable, and my very rough sense is that level of accuracy (i.e. 16 counts, or 1 mm) should be achievable. I am not incredibly confident about this answer, and I am even less confident speculating on what level of sub-millimeter resolution might be achievable.

Note that if you want finer resolution (in an absolute sense, not relative to the length of the actuator), you should consider using shorter linear actuators as the feedback potentiometer is spread out over a smaller distance.

- Ben

Thank you Ben.
I need a minimum 9 inch travel, so I might instead use a system based on stepper motor. It will drive a right angle screw jack gear reducer. I guess the precision of the stepper motor together with the gear reduction in the lead screw mechanism will mean a high resolution.

I am testing a LACT6P-12V-20 linear actuator controlled by a Jrk 21v3 motor controller configured with the settings file provided by pololu for this actuator. ( Just as recommended by pololu.

I am commanded the driver using the simplest “USB serial interface” configuration, this means through an usb wire connected between the controller (driver) and a Linux/Debian PC.

Theoretical resolution of the set is 150mm/4095=0.03663 mm or aprox 36.6 micrometers.
Performing several tests I have concluded that a practical resolution of 0.15 mm is the lower useful one.
I think this different is due to the potentiometer quality and its associated uncertainty.