A robot is a mechanical device that automatically performs work. It can accept human orders, run pre-programmed programs and act according to the principles formulated by artificial intelligence technology. Its task is to assist or replace human work, such as production, construction or dangerous work.

That is, the robot body, its arm generally adopts a spatial open-chain linkage mechanism, in which the motion pairs (rotating pairs or moving pairs) are often called joints, and the number of joints is usually the degree of freedom of the robot. According to the different joint configurations and motion coordinate forms, robot actuators can be divided into rectangular coordinate type, cylindrical coordinate type, polar coordinate type and joint coordinate type. For anthropomorphic purposes, the relevant parts of the robot body are often called base, waist, arm, wrist, hand (paw or end effector) and walking part (for mobile robot) respectively.

Born in science fiction, people are full of illusions about robots. Perhaps it is precisely because of the vague definition of robot that people are given full imagination and creative space.

According to the application environment, Chinese robotics experts divide robots into two categories, namely industrial robots and special robots. The so-called industrial robot is a multi-joint manipulator or multi-degree-of-freedom robot facing the industrial field. Special robots are all kinds of advanced robots except industrial robots, which are used in non-manufacturing industries and serve human beings, including service robots, underwater robots, entertainment robots, military robots, agricultural robots, robot machines and so on. Among special robots, some branches develop rapidly and tend to be independent systems, such as service robots, underwater robots, military robots and micro-manipulation robots. According to the application environment, international robotics scholars also divide robots into two categories: industrial robots in manufacturing environment and service and humanoid robots in non-manufacturing environment, which is consistent with the classification in China.

Aerial robots are also called unmanned machines. In the military robot family, UAV is the field with the most active scientific research activities, the greatest technological progress, the largest investment in research and procurement, and the richest practical experience. For more than 80 years, the development of UAVs in the world is basically based on the United States, which ranks first in the world in terms of technical level, types and quantity.