Lifetime of linear actuators

Help & Support Robot Parts
1

Hi, does anyone have any experience with linear actuators over a long period of time?

I am attempting to build a small boat that will cross an ocean. To do this, I require something to move the rudder based upon the GPS course over a period of many months.

A linear actuator would appear to do the job but I am unsure if one will last long enough. It is possible to purchase a ‘tiller pilot’ for about $500 which is essentially a linear actuator combines with a GPS. This is an off-the-shelf product and I hear people complain that they break too soon after installation, while others say that they are OK. I don’t know if power fluctuations have played a part in their downfall.

However, I intend to build my own as I will use something called PixHawk to navigate. It has the advantage that, with some coding, I can update the course remotely, but also automatically alter the heading based upon the direction of the wind.

An actuator has to move the rudder roughly every 10 seconds. If we set a maximum duration of 7 months, this is approaching 2 millions movements. It’s a lot to ask.

My main question is: Will a linear actuator be up to the task? Is there a better alternative?

2

Given th nature of the DC actuators, and the importance of the task, we would suggest considering other technology.
A DC linear actuator is essentially a DC motor with gearing, connected to a lead screw. As such, the reliability is really that of a DC motor.
Most DC motors have a duty cycle of around 25%, meaning they need 75% of the time to cool off.
In your application, they may need to operate continuously for extended periods of time in wet / humid conditions, which would reduce their life span.
As you indicated, 2 million repetitions is a lot, and well above what these actuators can handle.
You’re a pioneer in this regard. If we (or the community) think of any options, we will certainly post them here.

3

Thank you for the feedback.

I’m going to look into building a self-steering wind vane as this will do most of the work (with no amps needed) and a linear actuator would only be needed on a very occasional basis. Hopefully it is a perfect combination.

youtube.com/watch?v=WaOBTtk-8i0