(1) inertial navigation. Agv car is equipped with gyroscope, and the car has reference orientation when driving. Gyroscope measures acceleration, converts the coordinate values and acceleration of gyroscope into the current coordinates and direction of agv car, and compares them with the designated route. When the agv car deviates from the specified path, there will be a vector difference between the measured acceleration value and the specified value, and the deviation value can be obtained by integrating this difference twice, which can be used as the basis for correcting the driving direction. (2) Electromagnetic navigation. Bury underground cables along the predetermined running route. The cable is buried for 30 ~ 40 mm and wrapped with epoxy resin. The wire is connected with a low-frequency sine wave signal, so that an alternating electromagnetic field is generated around the wire. A pair of probes on the trolley can induce an error signal proportional to the running deviation of the trolley, which can drive the steering motor after amplification, thus driving the steering mechanism of the trolley and making the agv trolley run along the predetermined route. (3) Magnetic stripe navigation. Magnetic stripe navigation is similar to electromagnetic navigation, except that the guide wire is replaced by magnetic stripe, and an excitation coil is added outside the two detection coils. Because the magnetic field of the magnetic stripe is constant, the voltage will not be automatically induced in the detection coil. (4) Laser navigation. A series of reflectors are vertically arranged around the driving path of agv car in advance for laser guidance. The laser scanner installed on agv constantly scans the surrounding environment. When the reflector is scanned, the scanner can perceive it. As long as more than three mirrors are scanned, the controller can calculate the coordinates of the agv car in the current global coordinate system and the included angle between the normal of each mirror and the longitudinal axis according to the coordinate values of the mirrors, so as to realize accurate positioning and orientation. (5) Visual navigation. Visual navigation mode agv car uses strip road signs drawn on the ground as path identification, and uses computer vision to quickly identify the path. The optimal guidance controller can ensure the agv car to track the path accurately and stably. In the complex working environment of multi-parking lots and multi-branch paths, the designated target parking and target branch path tracking can be realized by recognizing the digital signs painted on the pavement in real time. By recognizing the special shape signs painted on the road surface in real time, the motion state control of vehicles such as acceleration, deceleration, right-angle turning and parking at special places can be realized. It has the functions of automatic obstacle avoidance, automatic alarm, automatic online and wireless communication.