This idea probably crossed my mind hundreds of times. Life would be better if there was a robot hair washing machine. I am certain my mom would be the first person to invest in a system like this to save her hand from over working. FYI, hairstylists need to condition their hands religiously. Otherwise, the skin would get rough patches due to overexposure of water and chemical. It ain't easy doing someone else's hair.
So, I found a video on Youtube and the lady above built a hair washing robot. I was actually excited to see how it works. One minute into the video I knew it was going to be a failed experiment. Anyways, I continue and finished the entire clip. Then I started looking for a real hair washing robot.
AND IT DOES EXIST.
After carefully examining the hair washing process I came to conclusion why I wouldn't invest in a hair washing robot. The thought of having a robot washing your hair is awesome but it's probably not practical. It would be difficult for a robot to detect the density and texture of hair and apply the right pressure.