Looking for some electronics guru who can help with my car project. Personally, my skill level/experience is below novice.

I have an ISIS system controlling the car electronics, including two of their optional components that allow me to control items via an ISIS supplied RF transmitter as well as an android smartphone.

Linear actuators open/close the doors and are controller by an Autoloc motor controller. You can program the run time for an actuator and when the motor controller sees a ground signal, it runs the actuator for the programmed time and then stops. Next time the motor controller sees ground, it reverses the polarity and runs the actuator in the reverse direction for the same time. If at any time during the up/down travel, it sees a ground signal, it stops the actuator. When it sees ground again, it reverses the polarity and the actuator runs the same distance in the opposite direction.

The problem:

The motor controllers allow for a certain amount of adjustability for "sensitivity". Even on the controllers highest setting, it is sometimes not enough to operate the doors. There is no binding, the actuators have well over the weight rating needed and in fact work 100% of the time if I run power directly to the actuator motor. When the doors are acting up/stalling on the open cycle, very slight one finger pressure assisting allows it to run the full travel without stopping.

I have searched for other motor controllers that might allow more adjustability of the force, but have not found anything with the features I need. So I am left with trying to improve the ones I have or finding another product to try out.

Here is a link to see the actuators working: https://www.youtube.com/watch?v=eHSa6tjS6PI

Also, I attached a picture of the different parts/how they work together.

Any suggestions are most appreciated!

the parts

  • 1
    \$\begingroup\$ I'm a bit confused by how this controller works. Instead of running for a set duration ("x seconds"), wouldn't it make sense to use actuators with limit switches and simply extend or retract to those limits? Or is there a requirement to use less than the full stroke? Do your actuators have any feedback (potentiometer) to allow the controller to determine position? Do you require speed control or is a constant speed acceptable? \$\endgroup\$ – JYelton Jul 29 '14 at 16:25
  • \$\begingroup\$ Per the actuator spec page it looks like they are just a motor and gearbox, with no feedback. So the question then is whether they have limit switches. There is no datasheet, so I can't find electrical information. They only provide a few pictures showing basic connections. I can determine is that model 39A is a 12" stroke, 12V DC, 100 lbf. actuator, but I expect you are trying to use less than the full stroke by way of the timed operation. \$\endgroup\$ – JYelton Jul 29 '14 at 16:37
  • \$\begingroup\$ There are no limit switches on the actuators, which is why I need the timed operation. These were the best actuators I could find for this application (fast, low noise, somewhat weather resistant and affordable). Speed control was not something I needed. Really appreciate you taking the time to read/reply to my post! \$\endgroup\$ – user50323 Jul 29 '14 at 16:52
  • \$\begingroup\$ I was going to invite you to chat to avoid extended discussion in comments, but you need 20 rep. It definitely seems like the controller is the problem here. Limit switches would simplify things; I would be worried that the timeout could fail, and the actuator bending or breaking something on my car. :) \$\endgroup\$ – JYelton Jul 29 '14 at 17:12
  • \$\begingroup\$ I am 3.5 years into this build, so bending/breaking things is high on my list of things to avoid :-) When I designed the bracket/how the actuator is mounted, I took this into consideration. The rod has a bolt through the end of it so at full extension, the rod stops just shy of the bolt. If something were to fail, it would be impossible for it to rip the door off. On closing, I am planning to determine where to install a bolt through the rod for the exact same reason. So there will be a mechanical barrier if the electronics somehow go haywire. \$\endgroup\$ – user50323 Jul 29 '14 at 17:54

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