I don't think the mechanical mechanism is that hard. Once they detect a weed ahead, they could just lower a small plough-like thing in worst case scenario. Or

I don't think the mechanical mechanism is that hard. Once they detect a weed ahead, they could just lower a small plough-like thing in worst case scenario. Or a pinch could go down, grab the weed and go up. But yes, they seem be secretive about the working.