Which of these is NOT a robot?

• A. Lego Mindstorms
• B. Mars Rover
• C. CNC milling machine
• D. Robowalker

Answer: (C)

A robot is a programmable system that can sense its environment, decide what to do, and act to perform tasks, often with mobility. Lego Mindstorms fits this idea because it’s a programmable kit with sensors and motors that you can program to respond to what it senses. A Mars Rover embodies a mobile, autonomous system that navigates terrain, collects data, and makes decisions to carry out scientific goals. A walking robot like Robowalker demonstrates locomotion, sensing, and control used to complete tasks in real environments. The CNC milling machine, however, is a computer-controlled tool designed to remove material along a fixed toolpath. It doesn’t sense, adapt, or decide based on real-time feedback in the way a robot does; it follows a predetermined program to perform a machining operation.