I had to look at original post to understand the objective.
It is usually not efficient, from an engineering perspective, to do an empirical 'hunt and peck' system when the results can be totally predicted in advance.
The sun can be considered at optical infinity, so it is like setting up a telescope with a clock motor drive such the axis of rotation is parallel with earth's axis (north star pointing in astronomy). The sun's distance allows the movement of the true earth polar axis to your location, keeping it parallel to original true polar axis, with little tracking error at your location even across the earth's daily rotation.
The solar panel is then bolted down on this polar rotational axis 'pole' with an offset tilt angle that points directly at the sun. From a solar panel perspective this is good for about a month but because of the precession of the earth (23.45 degrees) it requires this offset tilt to polar axis be adjusted for time of year to realign the panel-to-polar axis offset to point to the sun. Assuming northern hemisphere it will range +23.45 degrees in summer going to -23.45 degrees in winter relative to the polar rotational axis.
You said you wanted a single rotational axis.
A simple way is just to do the polar axis rotation based on time of day (with appropriate stop positions to avoid running the panel into the ground). The panel tilt angle offset to polar axis can be reset manually every month or two to improve tracking across the seasons. Some systems just set the panel parallel to polar axis and take the error. There is about a 10% worse case loss for this but still much better then a roof top fixed mount panel. When you put the 10% worse case loss up against the losses for clouds it does not amount to much additional loss.
A more complicated mechanics is a year based cam motor offset to automatically adjust the panel tilt angle to polar axis for time of year.
You could use an acme screw drive used for geostationary satellite dish adjustment for the polar axis time-of-day drive and a small acme screw drive for the seasonal panel offset tilt.
Some sites that may help.
https://www.electro-tech-online.com/custompdfs/2009/08/solartracker.pdf
**broken link removed**
Astronomical Applications — Naval Oceanography Portal