This document discusses various applications of robotics. It describes how robots can be designed with mechanical arms, transmission mechanisms, and engines. It also discusses the internal components of robots, including microcontrollers that act as the brain, motor drivers to control motors, sensors to sense the environment, and batteries as an energy source. The document then gives examples of using robots for underwater exploration, healthcare like surgery assistance, medical device sterilization and medication distribution, demining explosives, vacuum cleaning, industrial applications, and mobile robots for uses like assembly lines, industry, military, and security.