Specs: Linear actuators

The linear actuators that we are using are the PA-16 linear actuator by Progressive Automations.

Link to spec sheet:
https://www.progressiveautomations.com/media/catalog/pdf/Medium_Mini_Actuator_PA-16.pdf

Figure 1 - PA-16 linear actuator

What a beautiful actuator, huh? We have a way to link the actuator to the frame already, so that shouldn't be an issue. Our particular actuators have a stroke length of 4". 

Input voltage: 12VDC

Load capacity: 330 lbf

Figure 2 - Current vs. Load

I already mentioned that it has a load capacity of 330 lbf, but that is dependent on the amount of current we supply to the actuator. I'll have to check on how much force we'll actually need to apply in each axis... If we need less than 100 lbf, then we could be safe with supplying 3A of current to each actuator. I need to figure that out. I'm looking to save some money in regards to the Arduino motor shield.

Figure 3 - Speed vs. Load

Figure 3 shows the speed of the actuator versus the load. As the load increases, the actuator slows down. But it looks like the speed goes down by a very tiny amount. If we get loads up to 100 pounds, then the speed will have slowed from 0.20 in/s down to maybe 0.19 in/s, which may or may not affect anything. We are looking to control the speed of the actuators using PWM from the Arduino anyway. It may be noted, though, that the max speed we expect to reach per actuator is 0.2 in/s. Combining two of them moving in opposite directions, the maximum change in grip to grip distance will be 0.4 in/s. Now that I think about it, that is quite a bit!

So of course PWM will need to be utilized. Since the speed seems to be fairly consistent throughout the load, I am anticipating that we will not need to use feedback control. That is a good thing because we don't actually have any sort of encoder or anything in the actuators to begin with. Let's just hope we don't need to do that...

In general, the actuators give us the following specs to be followed by the other components:

Input voltage: 12VDC

Input current: 4A-24A (for 4 actuators), 2A-12A (for 2 actuators).

Max speed: 0.4 in/s (0.2 in/s/actuator).