Ellis
USA
Asked
— Edited
I have looked on the community and don't seem to be able to find a simple answer on how to control a Linear actuator.
What I am doing is making my Tin Man robot upper body rise up or down on command. I have a 12" actuator. It has two wires. To change directions you reverse the two wires. I would like to use one half of a Hbridge motor control. The motor control I have is a two in one Hbridge. I thought of using a movement control but I already have one controlling the wheels.
The linear actuator is moved by a 12v dc motor. I will power the actuator with 12v from my two twelve volt lead acid batteries. Do I just control the Hbridge with servo code. My linear actuator has limits up and down.
@Ellis,
For a 12" stroke linear actuator:
Limit switches only: https://www.pololu.com/product/2312 $104.95
Potentiometer & limit switches: https://www.servocity.com/hda12-2 $129.99
Linear Servo https://www.servocity.com/hdls-12-2-12v 299.99
for less than $25 you have a potentiometer.
maybe i'm wrong, but, it's not an easy task to add a potentiometer.
No reason to hack a linear actuator, there are many PWM servos on the market with pots for feedback. Every linear actuator contains two limit switches inside. No reason to add limit switches.
This company started the trend. Any linear actuators you see PWM at servo city or anywhere are rebranded.
https://www.firgellirobots.com
https://www.servocity.com/servos/linear-servos
Servo City has a wide range for any requirements, 2" to 12" stroke, speed and strength as you want. No extra electronics needed. They cost 300 $.
While you guys are pouncing - find out if he has the actuator because it was free? It’s a 12volt one, so I assume it’s quite heavy duty. Might be worthwhile to ask some questions and explore what he’s got and why?
I do agree, if there’s an option to purchase a correct actuator for the application... if that’s part of the plan. But, if you came across this actuator currently in your possession for much less than a new $299 purchase, it’s going to be more cost effective to retrofit.
If 1 height is all you need, be potentiometer will do that, it’ll simply need a larger diameter wheel on the end. Or, you can look into getting a multi turn potentiometer from digikey - that’s the easiest and most robust solution.
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I’d also like to leave this link. Their fast linear actuators move like 9 inches a sec with force ipto 33 pounds. They have a lot to offer at good prices.
https://www.progressiveautomations.com
I use to use a cable potentiometer on machines I built. Think of a retractable tape measure and how it works. Put a multi turn potentiometer in the middle of the drum and you have the concept.
Use a couple of pulleys to go around corners.
They work great for position feedback.
You can check this out.
https://youtu.be/NsgG6o2HFr4