Imagine you are a robotics researcher. You are free to use all the resources of the best Japanese university for any project you can think of. What do you do?
If it was me, I’d probably go for Grendizer, or a protocol droid at the least – but if your name is Nobuhiro Takahashi you are obviously a serious scientist, so you choose a sensible subject. Like a prototype unit to carefully study the interaction dynamics between humans and almost-lifelike androids. By spanking it on its naked butt. With a vibrator inside. You know, for science.