[Al Skierkiewicz]

Super,
The only issue would be heat. As the compressor does it's thing, the head gets hot. Upside down the heat from the head would rise into the body of the compressor. A fan might help. Do not use the vibration isolators that came with the pump though. They are designed for compression and I have seen them fail when used in other orientations. You can purchase other types as linked above or you can hard mount the pump. it will still vibrate and will make more noise as the vibration is transferred into the robot frame. You could also hard mount it on a small plate and then isolate the plate from the frame of the robot to quench vibration noise.