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Topic: H-Bridge & Actuator (for ballast tank control in AUV) (Read 502 times) previous topic - next topic

Spudrik

So i want to control this actuator, from my arduino uno. Also have a 12v battery pack to provide power to the actuator.

http://www.conrad-electronic.co.uk/ce/en/product/191857/Drive-System-Europe-12V-Linear-Actuator-100mm-Stroke-250N-29mms-12389

I have done some reading for the last couple of hours but im still not sure what i need to do. Am i right in saying that i need a h-bridge that can handle 3.2A or over and 12v or over. Would something like this do the job
http://www.ebay.co.uk/itm/12V-30V-5A-Bridge-Motor-Driver-Controller-Board-for-Arduino-Self-Balance-Robot-/231083298972?_trksid=p2054897.l4275

I need to be able to control the position of the actuator, not just extended/retract it fully. So would i need a relay as well, to allow the arduino to switch the device off/on.

retrolefty

#1
Dec 04, 2013, 08:16 pm Last Edit: Dec 04, 2013, 08:18 pm by retrolefty Reason: 1

So i want to control this actuator, from my arduino uno. Also have a 12v battery pack to provide power to the actuator.

http://www.conrad-electronic.co.uk/ce/en/product/191857/Drive-System-Europe-12V-Linear-Actuator-100mm-Stroke-250N-29mms-12389

I have done some reading for the last couple of hours but im still not sure what i need to do. Am i right in saying that i need a h-bridge that can handle 3.2A or over and 12v or over. Would something like this do the job
http://www.ebay.co.uk/itm/12V-30V-5A-Bridge-Motor-Driver-Controller-Board-for-Arduino-Self-Balance-Robot-/231083298972?_trksid=p2054897.l4275

I need to be able to control the position of the actuator, not just extended/retract it fully. So would i need a relay as well, to allow the arduino to switch the device off/on.


If you require variable speed for the actuator you will get best results using a H-drive with suitable voltage/current ratings. If you just want full speed,a couple of relays can perform the polarity reversal. You need to find out if your specific actuator has internal end of travel stop switches installed. If not you need to watch out for trying to drive the actuator past it's two physical travel stops.

As far as being able to determine shaft position you will need some kind of physical feedback signal to tell your sketch where in it's travel the actuator is. Some actuators like this offer a optional internal pot to track travel and provide you will a simple 3 wire connection to the pot to measure the travel. And finally I've seen some like this offer a optional 'servo interface' that includes the internal electronics to allow one to interface the actuator just like a simple R/C servo control which allows full position control using the standard arduino servo library code. OF course all options cost more so no free lunch around here.

Lefty

Spudrik

Thanks for the reply. Sadly i already have the actuator and it only has power and ground lines. A third line would have been a great help.

Full speed would be fine and it has end switches so thats one headache solved. I shall do some more research on relays and see what i can do with them.

However you have raised a new problem for me. With no internal feedback available, could i simply activate it and record the time taken to travel a certain distance then incorporate that into my code? Or would that be prone to errors. If not is there some sort of external system that could monitor position?

retrolefty

Quote

However you have raised a new problem for me. With no internal feedback available, could i simply activate it and record the time taken to travel a certain distance then incorporate that into my code?
Might work esp if the load is a fixed amount and your accuracy requirements is not too high. It's certainly worth playing with.

Or would that be prone to errors.
There is always some amount of error no matter what method is used, it's a matter of determining what accuracy you actually require for the project and then seeing if you can obtain it using timed movements.

If not is there some sort of external system that could monitor position?
Well there are linear pots that could be mechanically coupled to the actuator although that is not always easy getting the mechanics right. 

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