Greetings experts
I would appreciate some advice on selecting a proper stepper motor and driver for my project.
I plan to create an autopilot for my small fishing boat using a Raspberry Pi controlling a stepper motor, that rotates the steering wheel via a chain.
I will be getting the current heading from my existing Garmin GPS and the rudder angle from a potmeter on the rudder.
Here's a sketch of the system I plan on building:
Trying to figure out the minimum required torque to turn the wheel I took a good resolution kitchen scale
and pressed up on the wheel as shown below:
(Note: I can turn the wheel with my pinky with no effort at all)
I measured numerous times, and ended up somewhere between 200 - 250g to move the wheel.
I didn't calculate speed or acceleration into the equation as the motor will only travel a few degrees at a time,
and only very slowly. The wheel can only move ~3.5 turns from full port side to full starboard.
My first question is: Are my torque calculations are correct?
(I realize that using different sized cogwheels on the steering wheel and the motor affects the calculations.
I plan to use the same size on both ends)
In case my calculations are correct I went ahead and found a suitable stepper motor from a local supplier:
https://minielektro.dk/nema-23-stepper-motor-bipolar-1-8deg-0-9nm-57x56mm.html
Datasheet:
https://ecksteinimg.de/Datasheet/Schrittmotor/JK57HS56-2804/JK57HS56-2804-01.pdf
I oversized it on purpose (1.26 Nm), so I wouldn't run into any issues in that regard.
Next I tried to find a suitable driver for the motor, from the same supplier:
https://minielektro.dk/tb6600-stepper-driver.html
Datasheet:
https://www.mcielectronics.cl/website_MCI/static/documents/TB6600_data_sheet.pdf
The driver should be big enough (5A) with the motor rated at 2.8A, but my concerns are regarding the voltages.
The motors nominal voltage is 2.5V but the driver takes 9 to 36V.
I have 12V onboard.
I haven't worked with stepper motors/drivers before so I'm uncertain how the driver outputs/limits the voltage,
so my second question is: Can this motor and driver work together with 12V supply?
I would also appreciate some advice if anybody sees some obvious flaws in my design.
Thanks in advance.
I would appreciate some advice on selecting a proper stepper motor and driver for my project.
I plan to create an autopilot for my small fishing boat using a Raspberry Pi controlling a stepper motor, that rotates the steering wheel via a chain.
I will be getting the current heading from my existing Garmin GPS and the rudder angle from a potmeter on the rudder.
Here's a sketch of the system I plan on building:
Trying to figure out the minimum required torque to turn the wheel I took a good resolution kitchen scale
and pressed up on the wheel as shown below:
(Note: I can turn the wheel with my pinky with no effort at all)
I measured numerous times, and ended up somewhere between 200 - 250g to move the wheel.
I didn't calculate speed or acceleration into the equation as the motor will only travel a few degrees at a time,
and only very slowly. The wheel can only move ~3.5 turns from full port side to full starboard.
My first question is: Are my torque calculations are correct?
(I realize that using different sized cogwheels on the steering wheel and the motor affects the calculations.
I plan to use the same size on both ends)
In case my calculations are correct I went ahead and found a suitable stepper motor from a local supplier:
https://minielektro.dk/nema-23-stepper-motor-bipolar-1-8deg-0-9nm-57x56mm.html
Datasheet:
https://ecksteinimg.de/Datasheet/Schrittmotor/JK57HS56-2804/JK57HS56-2804-01.pdf
I oversized it on purpose (1.26 Nm), so I wouldn't run into any issues in that regard.
Next I tried to find a suitable driver for the motor, from the same supplier:
https://minielektro.dk/tb6600-stepper-driver.html
Datasheet:
https://www.mcielectronics.cl/website_MCI/static/documents/TB6600_data_sheet.pdf
The driver should be big enough (5A) with the motor rated at 2.8A, but my concerns are regarding the voltages.
The motors nominal voltage is 2.5V but the driver takes 9 to 36V.
I have 12V onboard.
I haven't worked with stepper motors/drivers before so I'm uncertain how the driver outputs/limits the voltage,
so my second question is: Can this motor and driver work together with 12V supply?
I would also appreciate some advice if anybody sees some obvious flaws in my design.
Thanks in advance.