In recent years, automatic mobile robots (AMR) have been widely concerned in various fields, such as material handling, unmanned aerial vehicle (UAV) cruise, automatic factories and so on. Compared with traditional robots, an AMR bring system poses several challenges such as adaptation to the environment, stable communication and robust control. For example, when in a complex environment, it can observe the surrounding environment in real time to avoid obstacles, and track the target in real time to change its trajectory until the task is completed, which improves the flexibility and mobility of the robot. More importantly, AMR systems require supports from various technologies including real-time positioning and navigation, trajectory planning, target tracking, multi-agent systems, robot monitoring and so on. In the near future, its geometric adaptability, design characteristics, mobility, flexibility, obstacle avoidance and fault-tolerant control will be further improved. This article gives a comprehensive elaboration on the four aspects of AMR systems, namely, AMR applications, perception technologies, robot communications, and control mechanisms. Future research directions are also pointed out.