I developed a patent pending prototype over the last few years with some spare time on pat leave.
My intention of the system is for off grid systems and commercial/industrial ground mount arrays where production is important.
I utilized relay logic for operating the wiper arm in manual or automatic mode. It uses a laser diffuse sensor to detect snow height on the solar panels and will automatically cycle across the array and clear the snow. It will clear with 1-2cm of buildup.
The system can be remotely operated and there are zero external electrical connections. It is powered with 12V LFP chemistry. It generally lasts over half a winter season before needing a recharge.
The wiper arm doesn’t actually touch the solar panels but has nylon door sweeps that are slightly above the panel faces. Snow that piles up acts as the “plow” contacting the glass.
So far some slight modifications in designs over the last few winters increased reliability. I can see switching to a PLC microcontroller in the near future may be best to handle fault conditions. 
