Doug Chiang - stap concept
Robot Sketches - looks like the robots from Machinarium.
Warbot from Rex, King of Space - Jonny Duddle
Robots by Spiros Karkavelas, found over at http://http://conceptrobots.blogspot.com
concept robots: Concept robots by Alexander Iglesias
Legs. | 17 Diagrams That Will Help You Draw (Almost) Anything drawing humans pencil sketch art prompt
Unisinos Institucional by Miagui Imagevertising