Can I control eight 12 volt linear actuators with arduino?

I need to build twin robotic arms that can lift heavy payloads, either under manual control or to preset positions. I intend to accomplish the heavy lifting with four 12 volt linear actuators per arm, but after days of searching, I haven’t found an example of this being done with Arduino.

I’m not concerned with the coding at this point; I have a decent grasp of that. But I can’t figure out if it’s physically possible to build the control system with Arduino components.

I think I can build it with an

If 5v power the relays is an issue, I could stack two shields, use two 5V 10A switching power supplies, and run four actuators per shield.

But I can’t afford to buy all the components only to discover that they don’t work as I think they will. Can anyone tell me if this is feasible, or if I am totally wrong?

You can control all these modules, of course. Whether the modules can control the actuators, and whether the actuators can lift the load, depends on the specific actuators, power supply, and last not least on the load.

A 5V 10A power supply may not be well suited for low currents. At least I'd not use it to power the Mega directly, for risk of over- or under-voltage. But the 12V supply may be fine for that purpose.

DrDiettrich,

Thank you for the response and verification! The part that I'm having trouble figuring out is how the potentiometer in each actuator is connected to the arduino with the 12v relays wired into the mix. I see how to connect 5v power on the arduino side of the relay, and I see how to wire in 12v power on the actuator side of the relay, but I'm not sure how to connect the potentiometer. Does it just connect back to a PWN pin on the arduino? Or does it connect into the relay bank somehow?

What pots? For position feedback? That won't work, if you drive the actuators by relays.

Until now you only described what you have. Now you should describe what you want to do with all these parts.

Post a link to the actuators.

DrDiettrich,

I thought it was possible to get/set position feedback with relays, based on step three of the tutorial linked below. They're using different components than I am, and they're moving one actuator rather than eight, so I'm not sure if it's possible to do what I want with the components I've identified in this thread.

I need to build two robotic arms that will look and move similar to a backhoe excavator (but smaller), and will have a hook rather than a bucket on the end. These arms will be used to lift items that weigh up to 50 pounds from an area lower than the base of the robot to a platform slightly higher than the base of the robot. I need to be able to move each arm individually with a control pad, or have them go through a sequence of preset positions in tandem with one another.

jremington,

I'm considering these actuators, but I'm open to suggestions:

Each actuator will require 5 amperes at full load and probably about 10 amperes start-up current, so only one can be moving at a time, per 10 amp motor power supply. If each actuator can be moving at any time, you need a 12V 10A power supply for each one.

It isn't clear what you would do with the servo driver -- it can't control the actuators.

For bidirectional control of each actuator, you need a double pole double throw (DPDT) relay or a motor driver. You can make the equivalent of a DPDT relay from two single pole double throw relays (as in the RobotGeek tutorial, but I use cheaper automotive relays), or four single pole relays.

If you want position control with those actuators, you could use a feedback-controlled DC motor driver like the Pololu JRK, or have the Arduino read out the pot and control the relays or motor driver as in the RobotGeek tutorial.

The duty cycle of the units you like to is only 25%, so one minute use means 3 minutes to cool off. Or that is how I read it.

Paul

I'd suggest to use motor drivers instead of relays, so that the actuator speed can be controlled as well. Driver modules with position control are still easier to use, just like servos.

Eventually temperature sensors should be added, to prevent motor overheating. 12V*5A is 60W operating power and heat. 8 actuators will consume 40A and 500W when active together, a nice heater device.