In modern buildings, elevators have become an indispensable vertical transportation tool. With the continuous advancement of technology, the intelligence level of elevators is also gradually improving. Among them, the automatic sensing function is crucial for enhancing the user experience and operation efficiency. The application of radar sensing technology has brought new changes to the automatic sensing of elevators.
I. Principle of Radar Sensing Technology
A radar sensor is a technology that uses radio waves for detection and ranging. Its working process mainly includes two key links: transmission and reception. The radar sensor emits radio frequency signals of a specific frequency. When these signals encounter an object, they will be reflected, forming an echo signal. After the sensor receives the echo, through a series of complex data processing algorithms, it can accurately calculate key information such as the distance, speed, and orientation of the target object. For example, in the common application of car reversing radars, the sensors on the rear bumper of the car emit ultrasonic waves under the instruction of the controller. When they encounter an obstacle, an echo is generated. The sensors receive and process the echo to determine the position of the obstacle and assist the driver in parking safely.
In addition, radar sensing technology also cleverly uses the Doppler effect. When the target object approaches or moves away from the radar sensor, the frequency of the reflected signal will change, and this phenomenon is called the Doppler frequency shift. By accurately analyzing this frequency change, the radar sensor can accurately measure the relative speed of the target object, thereby more comprehensively perceiving the motion state of the target object.
II. Advantages of Radar Sensing in Elevator Automatic Sensing
(1) High Sensitivity and Precision
Compared with traditional elevator sensing technologies, such as infrared sensing, radar sensing technology has higher sensitivity and precision. Taking the 60G elevator human body sensing sensor as an example, its sensing precision is as high as 95%, which can more accurately and safely sense the presence of the human body. In complex elevator usage environments, such as in situations with insufficient light, obstructions, or crowded people, infrared sensing may experience misjudgments or missed judgments. However, relying on its characteristic of using radio waves for detection, radar sensing can effectively avoid these problems and stably and accurately detect the presence and position information of the human body.
(2) Strong Anti-interference Ability
The operating environment of elevators is complex, with various interference factors, such as electromagnetic interference generated by metal structures. Aiming at this specific application scenario, radar sensing technology has demonstrated strong anti-interference ability. The 60G elevator human body sensing sensor has improved its anti-interference ability to metal through optimized design, ensuring that it can still work stably in an environment with many metal parts like an elevator and accurately obtain the signal of the presence of the human body, providing a reliable guarantee for the automatic sensing of the elevator.
(3) Flexible Sensing Range and Angle
Radar sensing technology has great flexibility in terms of the sensing range and angle. The sensing distance of some elevator radar sensors can reach 6 meters, and the sensing angle supports horizontal ±60° and pitch ±60° detection. This means that it can cover a large area. Whether inside the elevator car or at the elevator entrance, it can real-time obtain rich information such as the presence and orientation of the human body within the sensing range, providing comprehensive data support for the elevator control system, and thus more accurately controlling the operation and door opening and closing actions of the elevator.
III. Specific Application Scenarios of Radar Sensing in Elevators
(1) Detection of Human Presence at Elevator Landings
Installing a radar human presence sensing module above each elevator landing is an important part of realizing the intelligent operation of the elevator. This module detects the human presence signal by emitting electromagnetic waves and converts it into an electrical signal for output. When someone enters its sensing range, the module will output a high level; conversely, when there is no one in the sensing range, it will output a low level. During the operation of the elevator, the elevator system will continuously read the output signals of these radar human presence sensing modules. Once it detects that the passengers have left the landing, that is, it reads a low level signal, the elevator system will automatically cancel the button call for that floor through a preset program, effectively reducing the invalid stops of the elevator, greatly improving the operation efficiency of the elevator, and avoiding energy waste.
(2) Intelligent Control of Elevator Door Opening and Closing
In the control of elevator doors, radar sensing technology also plays a key role. When the elevator arrives at the floor and is ready to open the door, the radar sensor installed near the elevator door will monitor the human situation in the door area in real time. If it detects that someone is waiting at the door, the elevator door will open normally; if no one is detected waiting within the detection cycle, the elevator door may not open and will directly execute the next operation instruction. During the closing process of the elevator door, the radar sensor also keeps monitoring at all times. Once it detects that an object (such as a human body) enters the door area, it will immediately stop the door closing action and reopen the door to ensure the safety of passengers and prevent accidents such as people being caught.
(3) Association of Intelligent Control Inside the Elevator Car
In addition to its applications at the elevator landing and on the elevator door, radar sensing technology can also be associated with other systems inside the elevator car to achieve more comprehensive intelligent control. For example, connecting the ventilation, lighting and other systems inside the elevator to the radar sensor. When the sensor senses that there are people in the car, it will automatically turn on the ventilation and lighting systems; when it detects that there are no people in the car, it will automatically turn off these systems, thereby achieving the goal of energy conservation and also improving the intelligent management level of the elevator.
IV. Practical Application Cases and Effects
A large commercial complex introduced an elevator automatic sensing system based on radar sensing technology during its upgrading and renovation. Before the renovation, due to the limitations of traditional sensing technology, the elevator often made invalid stops. Especially during non-peak hours, there were an average of 5-8 invalid stops per hour, resulting in low operation efficiency of the elevator and increased energy consumption. After the renovation, 60G elevator human body sensing sensors and supporting radar human presence sensing modules were installed. After a period of data statistics, the number of invalid stops of the elevator was greatly reduced, with an average of only 1-2 invalid stops per hour. The operation efficiency of the elevator increased by about 30%, and the energy consumption decreased by about 15%. Moreover, due to the high precision and stability of radar sensing technology, the occurrence of safety accidents such as people being caught by the elevator was effectively reduced, and the riding experience and satisfaction of customers were improved.
V. Summary and Outlook
Relying on its unique advantages, radar sensing technology has shown great application potential in the field of elevator automatic sensing. Through comprehensive applications at the elevator landing, on the elevator door, and inside the elevator car, it not only improves the operation efficiency and safety of the elevator but also brings users a more convenient and comfortable riding experience. With the continuous development of technology, radar sensing technology is expected to be further optimized. For example, breakthroughs can be made in reducing costs and improving integration, so as to be more widely applied to various types of elevators and promote the entire elevator industry to move towards intelligence and high efficiency. In the future, we have every reason to believe that radar sensing technology will continue to inject new vitality into the development of elevator automatic sensing technology and bring more convenience and surprises to people's vertical travel.
