Pillowing on top of print on my R2

I'm using Cura for Robo and running the recommended (non-custom) PLA settings for my prints. I'm selecting the light fill. I'm noticing Pillowing on the top of my print. similar to this. It is only in a certain area that it happens on one specific print, which would be the biggest area of infill for the part (makes sense). Most of the other areas consist more of edges, so there is very little infill going on. Almost everything is close to a solid fill because the walls are so thin.

The reading i have found says there are typically a few ways to resolve this issue; increase the fan speed on the top layers, increase the number of top layers, and possibly increase or reduce the fill density. Has anyone else had this issue with their prints and if so, can you make any recommendations on what changes should be made to help my cause? I'm new to Cura for Robo, because I was using the MatterHackers software on my R1+. I was hoping to stay with the recommended settings as much as possible without futzing with the settings if possible. But, with 3D printing, I know that changing the settings based on the part being printed may ultimately be the answer, since all 3D designs could exhibit different problems based on the shape, size, etc.

I poked around in the custom settings, but I couldn't find a setting for the fans for the top layers only.
Thanks in advance.

 

Shell wall and top/bottom thickness default to 1mm, which is what it is set to.

 

Here is a close-up of the end that has the issue. It pillows on the end, but as you can see, as it goes up the shaft it doesn't pillow, because it is actually hollow under there and it is mostly edge fill instead of infill. the pillowed part is infill. Hopefully that makes sense.

 

I own an R1+, not an R2, so I don't know what the R2's fan configuration is; however, on my R1+, the default fan setup was pretty bad. (Basically, the fan just pointed roughly in the direction of the area being printed.) I printed a new fan duct from Thingiverse and that reduced pillowing and other problems. (The new setup directs the fan's output to a much narrower area of the print bed, thus improving its efficiency.) I see a couple of R2 fan duct designs on Thingiverse, so you might look into such an upgrade. OTOH, the R2 might not really need it. I'm just tossing this out as something you might want to investigate.

 

Good news... increasing the fill from 'light' to 'dense' when using the recommended settings in Cura for Robo completely resolved the issue of pillowing on the top of my print. The default infill for 'light' is 20% and dense defaults to 50%. So, somewhere in there between 20% and 50% is my real answer. Thanks to all who posted suggestions.