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+--- Thread: Stepper driving leadscrew (/showthread.php?tid=2073)
Stepper driving leadscrew - trebleplink - 2019-11-09
Hi all, Chris here from Bowling Green, Ky. Restoring a Rhodes 28' sailboat (tiller) and plan to singlehand a lot. I'm primarily an electronics guy, but have a small home machine shop.
I've been talked out of the tiller pilots and similar, hearing serious reliability issues. I have a 5/8" stainless leadscrew, and a bronze bearing. I'm wondering if anyone has driven this kind of thing with a nema 23 size stepper using a commercial stepper driver? Would I need an additional arduino to glue the driver to the autopilot's output? A stepper may not be ideal, but I'm not sure I like a standard brushed motor with gearbox in a marine environment ...
RE: Stepper driving leadscrew - seandepagnier - 2019-11-09
(2019-11-09, 05:30 PM)trebleplink Wrote: Hi all, Chris here from Bowling Green, Ky. Restoring a Rhodes 28' sailboat (tiller) and plan to singlehand a lot. I'm primarily an electronics guy, but have a small home machine shop.These break usually for:
I've been talked out of the tiller pilots and similar, hearing serious reliability issues. I have a 5/8" stainless
1) stripped gears/belts broken belts
2) water in electronics
If you keep the electronics below and dry it will solve #2. The motor controller in pypilot has protection from stalling, and soft start which helps a lot with #1 but can still happen with the wrong settings.
Quote: leadscrew, and a bronze bearing. I'm wondering if anyone has driven this kind of thing with a nema 23 size stepper using a commercial stepper driver? Would I need an additional arduino to glue the driver to the autopilot's output? A stepper may not be ideal, but I'm not sure I like a standard brushed motor with gearbox in a marine environment ...
The cheap tiller pilots use this. The better ones use ball screws. Usually there is a brushed dc motor and belt or gear to the lead screw rather than a stepper motor.
If the stepper motor has enough torque (not sure about nema23 if it's enough) it could go directly with a coupling, but then you would need to modify the motor controller sketch to drive a stepper motor.
brushed dc motors are better for this application unless you have a closed loop stepper controller. They are good enough for autopilots and don't require an extra sensor like the alternatives.
A more efficient alternative is to use a brushless motor with sufficient torque to drive a ball screw directly. It should also have angular sensor on the shaft.