Sun Tracking Solar Control System

telescopes use this type of tracking system.

one of my friend also did the similar project in final year .....you will be needing high torque, low R.P.M motor for panel movement, working on feed back control.

IMO, for two-axis rotational control you'll need electrically operated actuators....

Check out Mother Earth News for DIY solar tracker frames etc. Do a Google search to find it. I could provide you with a long list of great DIY solar energy websites, but I really don't have the time this aM to copy and paste the links to my posting.

Good luck!

Mechanically you could build a single axis system, with that axis parallel to the Earth's axis. This axis can be made to track the sun with a single motor control turning the axis at rate of 1 revolution per day (needless to say), then slewing from West back to East at sunset.

If you really want to do a second axis you could add an axis orthogonal to the polar axis, which will allow the solar panel to track the Sun as it goes North and South of the celestial equator. The range of motion needed for this axis will be +/- 23.5 degrees, since that is the total angular movement of the Sun from the Equator. (Though of course this motion is very slow, since it's tracking the Sun through the seasons, going from 0 to +23.5 in the Spring, +23.5 to 0 in the Summer, etc.)

Here's a very simplified sketch of the frame and its axes.

Usbport has a good reply. I have done something (Didn't get it finished) that was on a pallet as an "equatorial platform" . (This is basically the same as USB port's thing but it should be easier to aim accurately. It is a total junk reuse thing. http://www.youtube.com/watch?v=MFTEGjkRazk shows a method to aim it with a "solar compass" and declination tables. (USBport's thing and the pallet must be aimed accurately north south or there will be errors). I also did the preliminaries on a low tech "liquid piston" dripper tracker. It is on http://solarcooking.wikia.com/wiki/Solar_tracking Before that I made waterclock dripper trackers to turn my parabolic dish. (Half dish). I think there are videos about them there too. My experiments were pretty crappy and I was hardly ever there for a full day but the drippers were very powerful and very stable too. The liquid piston tracker was "perfect" for a student on the uvic mecatronics course but they did not use it because I am not a business.

Anyway, to cut a long story short, the pallet and some sort of 3 or 4 wheeled thing on it, (like a shop vac on a track) would work as the primary axis. It is easier to align north south than the frame that USBport shows.

Brian

Actually the polar axis only needs to be within a few degrees of parallel to the Earth's axis, and there are ways to do this fairly easily -- align at night on Polaris, use a compass with a set of correction tables for true north, a GPS; there is probably even an iPhone App.

The above is true if the panels are open-frame mounted, so that there is no shadowing of the panels when misaligned (such as a shadowbox frame would cause). The alignment efficiency goes as the cosine of the mis-alignment angle, so the mis-alignment could be off by 5 degrees and the alignment efficiency would still be 99.6%.

Look for information on what is typically called an equatorial drive or Equatorial_mount.

Do you really need 2-axis tracking? Daily tracking only requires single axis movement. Seasonal adjustment does require a second axis, but this change is slow and can be accomplished by occasional (~1 degree weekly) manual adjustments.

Follow links and download/review pdfs for these simple single axis mechanical "clock" drive trackers.

http://cr4.globalspec.com/comment/587677/Re-How-to-Design-and-Make-a-Low-Cost-Low-Tech-Solar-Tracking-System

You may be able to adapt these designs for electrical motor control. Good luck on your project!

Here's a good link regarding the definition of a telescope equatorial mount along with some photos of large telescopes:

http://en.wikipedia.org/wiki/Equatorial_mount

IF you are so inclined and equipped to construct your own equatorial mount, here is a great website on how to construct a mount together with the clock motor (and worm gears/slip clutch):

http://www.astronomiainumbria.org/advanced_internet_files/meccanica/easyweb.easynet.co.uk/_chrish/eqnotes.htm

As an avid Newtonian reflector telescope builder for many years (I currently have a 12-inch diameter scope on a Orion equatorial mount w/ clock drive) my suggestion to you is not to build it unless you have access to a fully equipped metal machine shop and the necessary machining skills.....you'll need a CNC-controlled multi-axis milling machine and a metal lathe for starters.

Personally, if I were you I'd buy a ready-made equatorial mount and clock drive for your solar tracker OR buy the mount without the clock drive and electric motor and built the necessary tracker circuits. You can even find them for sale on Ebay for a good and reasonable price. Just make darn sure it's beefy enough to support the solar panel frame and PV solar array weight under wind loading! You'll also need to support this contraption, either with a stationary frame or a steel pipe support pole anchored into the ground in a concrete collar pier.

Here's a couple of good websites:

http://solar.physics.montana.edu/larson/Capella/

http://members.ziggo.nl/jhm.vangastel/Astronomy/Poncet/e_index.htm

Here's a very good and clear pic of a manufactured mount similar to my equipment:

Good luck with your project!