Autosteer - step motors

Hi. Does anyone use step motors for autosteer?

Currently planing an experiment with a stepper motor: AOG without wheel angle sensor - #20 by doppelgrau

But no experience yet.

In the telegram group you can find a guy, Alexander, who is using a stepper motor

Not sure a stepper motor is useful here or appropriate, if you’re using a WAS. Absolute position of the motor itself isn’t that necessary if you have WAS feedback. It’s more equivalent to a closed-loop servo system.

What is WAS?

Wheel angle sensor

Wheel Angle Sensor, the potentiometer-like device used to detect the angle of one of your front wheels. Output: voltage (about 2.5V = 0°, when mounted correctly)


I setup stepper motor with AOG - second Arduino control stepper motor driver based on PWM from main Arduino (original autosteer program) :wink:

Sure, stepper motors will work, but what is the benefit? A DC motor takes the current, it needs for a given torque. For a stepper motor, you have to inject a current that is higher than for the torque needed, otherwise the motor won’t run. So you need (much) more electrical power. The only benefit I see is to avoid the need of a WAS. doppelgrau is working on that as he mentioned above, let’s see. I personally prefer a DC motor + encoder for the reasons I mentioned above.

Yeah but stepper motor not required any Gearset (planetary etc). I mount it directly to steering wheel and I can steer manually with engaged (of course disabled :sweat_smile:) . Stepper motor have more torque in lower speed so it not required any gearset :wink:

I am working on a stepper-motor solution for my NH, but it is still not as expected.
Some gearratio is required. I have printed 2 different diameters for the gears, but still not satisfying. I have increased (NEMA23) motor tourque from 1Nm to 3Nm with full steps, supply voltage from 12v to 36v, but still … :worried:
The Gt2-belt solution was promising, but the motormount is more difficult to get a constant tension in both rotation directions. (i had slipping in one rotation direction)
The printed gear distance has to be fixed, because otherwise it looses to much torque due to friction of the gears. (I had just pressed the motor onto the stearingwheelgear with a strong rubberband)

I am using accelstepper library included in the arduino nano-autosteer sketch. But still debugging/improving logic.

Due to the fact that my steeringwheel position is not always the same for a given tire-position, i have to use a WAS and update the virtual (stepper) position to the real center in the code.

Trying to use the already implemented configuration possibilities to adjust stepper-stepps-per-degree of the WAS, max acceleration and max stepper speed.

At slow spees the stepper is realy nice to get a perfect position, but there is an increasing tourque loss on speed.

I will get it to work, but it is not as easy as i expected, but the winter is long … :grin:

IMG_20200828_120331 IMG_20200828_120334 IMG_20200913_153919 IMG_20200913_153925


@hagre very nice work! What kind of center sensor are u using? I’m working on a WAS-free system as well, but my test with an inductive proximity switch was not satisfying so far (no clear switching point).

Okay could you please write here all components I need for stepper motor properly work? I can’t find all in one because there are lot of components I think…

You have to small gearset and motor. I use bigger motor without any problems :wink:

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@GoRoNb At the Moment i am still using a normal WAS to Update the virtual-stepper Position frequently. In the future, i would like to remove the WAS and use just a “center-switch” on the hydraulic actuator.

unfortunately this center switch is trickier than expected to me. Inductive proximity switches seem not suitable (at least my one). Testing with a magnetic sensor right now…

Let’s list what features an ideal engine for an autoster should have:
High torque
Small dimensions
Quiet work
Quick change of direction (no rotor inertia)
No resistance (free turning of the steering wheel) after turning off the power.
It seems to me that the above conditions are best met by a simple brushless motor.
If we have a steering sensor, the stepper motor does not make sense because it has more disadvantages than advantages. The control loop is based on the indications of the steering sensor anyway and measuring the steering wheel turns does not make sense.


And I think that stepper motors aren’t fast enough for uturn

it also could be an brushed motor without gearbox . . .

Hey how did you set up the code/make sign control a stepper?