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nhtshot
06-06-2011, 01:23 AM
I'm building something diesel powered and looking for a servo of some kind to manage the throttle.

I've googled the heck out of this and found many options, but I'm just not familiar enough with the companies or options to really know what the right choice is.

Originally, I was thinking that a linear motor would be the way to go with this. All I need is a motor and a pot. My controller has an h-bridge, hardware PWM and plenty of CPU power to do the PID control. However, most of the "linear actuators" I've found are screw type. Since this is controlling a throttle, I cannot have a screw. It's absolutely mandatory that I can put a spring on it and have it fail safely (shutting down the engine).

I'm also not a very big fan of "r/c" type servos. With all of the gearing they use, the spring has to be fairly large. Of course, a large spring means that the servo requires significantly more torque in order to operate or I give up speed.


OK, requirements:

Linear:

2 inch stroke
1-2kg force (the actual diesel pump only needs about 200-300g of force, but I'm expecting to use a 1kgf spring)
2-6 inches/sec speed

Servo:
2Nm torque (20 kgf. cm)
.25 sec/60Degrees
No need for control electronics. In fact, I'd prefer to find a servo body without controls and do that myself.

I also need this to be 24V.

Does anybody have any thoughts?

Thanks.

sarendt
06-11-2011, 05:34 AM
Have you considered a solenoid? It might work for you, as it seems like you have plenty of room, weight and power. http://en.wikipedia.org/wiki/Solenoid You can Google them and find lots of good information and places to buy. Cheers, Scott