AGV mobile robots mainly utilize the following five positioning technologies:
I. Ultrasonic Navigation and Positioning Technology for Mobile Robots
The working principle of ultrasonic navigation and positioning is similar to that of laser and infrared. Typically, ultrasonic sensors emit ultrasonic waves from their transmitting probes, and these waves return to the receiving device when they encounter obstacles in the medium.
By receiving the reflected ultrasonic wave signal emitted by itself, and calculating the propagation distance S based on the time difference between the emission and reception of the ultrasonic wave and the propagation speed, the distance from the obstacle to the robot can be obtained. The formula is: S=Tv/2, where T is the time difference between the emission and reception of the ultrasonic wave, and v is the wave speed of the ultrasonic wave in the medium.
Due to their advantages such as low cost, fast data acquisition rate, and high distance resolution, ultrasonic sensors have long been widely used in the navigation and positioning of mobile robots. Furthermore, they do not require complex image processing techniques when acquiring environmental information, resulting in fast ranging speed and good real-time performance.
Furthermore, ultrasonic sensors are not easily affected by external environmental conditions such as weather, ambient light, shadows from obstacles, and surface roughness. Ultrasonic navigation and positioning have been widely applied in the perception systems of various mobile robots.
II. Visual Navigation and Positioning Technology for Mobile Robots
In visual navigation and positioning systems, the most widely used method both domestically and internationally is the navigation approach based on local vision, which involves installing onboard cameras within the robot. In this method, control equipment and sensors are mounted on the robot's body, while high-level decisions such as image recognition and path planning are handled by the onboard control computer.
In simple terms, the working principle of a visual navigation and positioning system is to perform optical processing on the robot's surrounding environment. First, a camera is used to collect image information, which is then compressed and fed back to a learning subsystem composed of neural networks and statistical methods. The learning subsystem then links the collected image information with the robot's actual position to complete the robot's autonomous navigation and positioning function.
III. GPS Global Positioning System
Currently, pseudorange differential dynamic positioning is commonly used in navigation and positioning technology applications for intelligent robots. This method involves using a base receiver and a dynamic receiver to jointly observe four GPS satellites, and then calculating the robot's three-dimensional position coordinates at a specific moment using a specific algorithm. Differential dynamic positioning eliminates satellite clock errors. For users located 1000km from the base station, it can eliminate satellite clock errors and errors caused by the troposphere, thus significantly improving dynamic positioning accuracy.
IV. Mobile Robot Optical Reflection Navigation and Positioning Technology
Typical optical reflection navigation and positioning methods primarily utilize laser or infrared sensors for distance measurement. Both laser and infrared sensors employ optical reflection technology for navigation and positioning.
A laser global positioning system typically consists of a laser rotation mechanism, a reflector, a photoelectric receiver, and a data acquisition and transmission device. While infrared sensing positioning also offers advantages such as high sensitivity, simple structure, and low cost, its high angular resolution but low distance resolution means it is often used as a proximity sensor in mobile robots to detect nearby or suddenly moving obstacles, facilitating emergency obstacle stopping for the robot.
V. Currently, the mainstream robot localization technology is SLAM technology.
Most leading service robot companies in the industry have adopted SLAM technology. Only SLAMTEC holds a unique advantage in SLAM technology. So what exactly is SLAM technology? Simply put, SLAM technology refers to the entire process by which a robot completes localization, mapping, and path planning in an unknown environment.
SLAM (Simultaneous Localization and Mapping), since its inception in 1988, has primarily been used to study the intelligent movement of robots. For completely unknown indoor environments, equipped with core sensors such as LiDAR, SLAM technology can help robots build maps of the indoor environment, facilitating autonomous movement.
