In the current context of continuous upgrading of automated logistics and industrial production, the Automatic Guided Vehicle (AGV), as a crucial automated equipment, its safety performance is of vital importance. The anti-collision sensor, as the core component ensuring the safe operation of the AGV, is directly related to the smoothness of production operations and the safety of personnel and equipment. With its many unique advantages, radar sensing technology is being increasingly applied in the field of AGV anti-collision sensors, providing a reliable guarantee for the safe operation of AGVs.
Principles and Characteristics of Radar Sensing Technology
The working principle of a radar sensor is based on the transmission and reception of electromagnetic waves. It emits electromagnetic waves of a specific frequency into the surrounding space. When the electromagnetic waves encounter an object, they will be reflected, and the reflected waves are received by the radar sensor. By accurately measuring the time difference between the transmitted wave and the received wave, and based on the propagation speed of electromagnetic waves, the distance between the target object and the radar sensor can be accurately calculated. For example, in a common millimeter-wave radar, the electromagnetic waves in the millimeter-wave frequency band it emits have a short wavelength, which makes the radar perform excellently in spatial resolution and enables it to keenly capture the reflection signals of tiny objects.
At the same time, the radar sensor can also obtain the relative speed information of the target object by means of the Doppler effect. When the target object moves relative to the radar sensor, the frequency of the reflected wave will change, that is, the Doppler frequency shift. Through the precise analysis of this frequency shift, the radar sensor can accurately determine whether the target object is approaching or moving away, as well as the magnitude of its movement speed.
Radar sensing technology has a series of remarkable characteristics. Firstly, it has strong anti-interference ability. Compared with other types of sensors, such as optical sensors that are easily interfered by environmental factors such as light changes, dust, and smoke, radar sensors are minimally affected by these factors. In industrial production workshops, there are often a large amount of dust, smoke, and complex lighting conditions, but the radar sensor can still work stably and accurately detect surrounding objects. Secondly, it has the ability to work around the clock. Whether it is day or night, or in adverse weather conditions such as rain, snow, and fog, the radar sensor can operate normally and continuously provide reliable environmental perception information for the AGV. Thirdly, it has a relatively long detection range and high precision. The detection range of different models of radar sensors can reach several meters or even dozens of meters, and it can achieve high precision when measuring distance and speed, providing sufficient early warning time and accurate data support for the safe operation of the AGV.
Application Modes of Radar Sensing in AGV Anti-collision
In the actual operation process of the AGV, radar sensing technology mainly realizes the anti-collision function through the following methods. Firstly, radar sensors are installed at multiple key positions of the AGV body, such as the front, rear, and sides of the body. These sensors are like the "eyes" of the AGV, monitoring the surrounding environment in real time in all directions. When the radar sensor detects the presence of an object around it, it will quickly transmit information such as the distance and speed of the target object to the control system of the AGV.
After receiving the data transmitted by the radar sensor, the control system of the AGV will analyze and process these data according to the preset algorithm. For example, by calculating the intersection time between the target object and the current driving path of the AGV, it can determine whether there is a collision risk. If the system determines that there is a collision danger, it will immediately take corresponding obstacle avoidance measures. These measures include controlling the AGV to slow down to reduce the impact force of a collision; or adjusting the driving direction of the AGV to guide it to bypass the obstacle, thus avoiding the occurrence of a collision accident.
Take the AGV in a certain logistics warehouse as an example. During the operation of this AGV, the radar sensor at the front of the vehicle detected a stationary cargo pallet 2 meters ahead. The sensor quickly transmitted the distance information to the control system. After analysis and calculation, the control system determined that a collision would occur if it continued to travel at the current speed. Therefore, the control system immediately issued an instruction to make the AGV start to slow down and, at the same time, planned a new driving path, and finally successfully avoided the cargo pallet, ensuring the safety of itself and the cargo.
In addition, some advanced AGV systems also adopt the multi-radar sensor fusion technology. By fusing and processing the data obtained by multiple radar sensors, the accuracy and comprehensiveness of the AGV's perception of the surrounding environment can be further improved. Radar sensors at different positions can detect the target object from different angles, complementing each other's information, effectively reducing the detection blind area, and enhancing the obstacle avoidance ability of the AGV in complex environments.
Advantages of Radar Sensing in AGV Anti-collision Applications
Compared with traditional AGV anti-collision sensors, such as ultrasonic sensors and infrared sensors, radar sensing technology shows many obvious advantages in AGV anti-collision applications. Firstly, in terms of detection range, the radar sensor has a longer detection range. Generally, the effective detection range of ultrasonic sensors is relatively short, usually within a few meters, which makes it possible that the AGV may not be able to detect distant obstacles in time when traveling at high speed, thus increasing the collision risk. However, the detection range of the radar sensor can reach dozens of meters, which can provide more sufficient early warning time for the AGV, enabling it to have enough time to react and take obstacle avoidance measures.
Secondly, in terms of accuracy, the radar sensor has higher measurement accuracy. It can accurately measure the distance and speed of the target object with a very small error range. For example, in some industrial production scenarios with extremely high requirements for positioning accuracy, the AGV needs to accurately dock at the designated position for loading and unloading goods. The radar sensor can provide high-precision position information for the AGV, ensuring its accurate docking and avoiding collisions or loading and unloading errors caused by positioning errors.
Furthermore, in terms of adaptability to complex environments, the radar sensor performs excellently. As mentioned earlier, when ultrasonic sensors and infrared sensors encounter complex environments such as dust, smoke, and strong light, their performance will be seriously affected, and they may even make misjudgments or be unable to work. However, with its strong anti-interference ability and all-weather working characteristics, the radar sensor can operate stably in various complex environments, accurately detect surrounding objects, and ensure the safety of the AGV. For example, in a food processing workshop, there are often a large amount of steam and water mist in the environment, and ultrasonic sensors and infrared sensors can hardly work normally, but the radar sensor can easily cope with it and provide reliable obstacle avoidance support for the AGV.
