In the vertical transportation system of modern buildings, elevators have become an indispensable part. From towering skyscrapers to residential communities where people live daily, the efficient and safe operation of elevators is related to all aspects of people's lives. With the rapid development of science and technology, various advanced technologies are constantly integrated into the elevator field. Among them, radar sensing technology, with its unique advantages, is bringing about a new revolution in elevator automatic sensing and has become a key force in improving elevator performance and user experience.
I. Analysis of the Principle of Radar Sensing Technology
Radar, as an electronic device that uses electromagnetic waves to detect targets, has a sophisticated and efficient working mechanism. In the application of elevator automatic sensing, it mainly relies on two common radar technologies: Doppler radar and Frequency Modulated Continuous Wave (FMCW) radar.
Doppler radar utilizes the Doppler effect. When the emitted electromagnetic waves encounter moving targets such as the human body, the frequency of the reflected waves will change. By detecting this frequency shift, it can sense the motion state of the target, such as whether someone is approaching the elevator or moving inside the elevator. For example, when a passenger walks quickly towards the elevator, the Doppler radar can quickly capture the increase in the frequency of the reflected wave, thus triggering the relevant response mechanism of the elevator in a timely manner.
The FMCW radar emits a continuous wave whose frequency changes linearly with time and measures the frequency difference between the emitted wave and the reflected wave to accurately obtain information such as the distance, speed, and angle of the target. It can construct a detailed "picture" of the environment around the elevator, not only accurately determining the presence of people but also determining their specific positions, providing rich data support for the intelligent operation of the elevator.
II. Diverse Application Scenarios in Elevator Automatic Sensing
(1) Intelligent Opening and Closing Control of Elevator Doors
In traditional elevator door control, infrared sensing is a common method. However, in complex environments, such as under strong light interference or in a dusty environment, its accuracy is easily affected. The introduction of radar sensing technology has greatly improved the reliability and accuracy of elevator door opening and closing control. At the elevator landing, when a passenger enters the radar sensing range, the radar can instantly detect the human body signal and quickly transmit it to the elevator control system, instructing the elevator door to open smoothly. Moreover, during the closing process of the elevator door, if the radar detects an object blocking the door, even the slightest movement, it can immediately send a signal to make the elevator door stop closing and open again, effectively preventing accidents of pinching people or objects. Take the elevators in crowded places such as shopping malls as an example. Radar sensing ensures that the elevator doors can always respond quickly and accurately during frequent passenger access, maintaining efficient passenger flow transportation.
(2) Personnel Detection and Intelligent Services in the Car
Inside the car, the radar sensor also plays an important role. It can monitor the number and position distribution of people in the car in real time. Based on this data, the elevator can achieve intelligent ventilation and lighting control. When there is no one in the car, it automatically reduces the ventilation power and dims the lighting brightness to achieve the goal of energy conservation and emission reduction; once someone enters, it immediately restores to the normal operation state. In the elevators of some high-end office buildings, through the accurate detection of the people in the car by the radar, the intelligent floor recommendation function can also be realized. The system automatically recommends the most likely floor to go to according to the daily riding habits of people and the current distribution of people in the car, simplifying the operation process for passengers and improving the riding efficiency and experience.
(3) Passenger Monitoring in the Floor Waiting Area
To reduce the ineffective stops of the elevator, installing a radar human presence sensing module above each elevator landing is a key measure. This module continuously detects whether there are passengers in the floor waiting area by emitting electromagnetic waves. When a passenger enters the waiting area, the module outputs a high-level signal to the elevator control system; if the passenger leaves, the signal becomes a low level. During the operation of the elevator, the control system intelligently determines whether it is necessary to stop at this floor according to these signals. For example, during the non-peak hours of an office building, if there is no one in the waiting area of a certain floor, the elevator can directly skip this floor, reducing unnecessary stops, greatly improving the overall operation efficiency, reducing energy consumption, and at the same time shortening the waiting time for other passengers.
III. Significant Advantages of Radar Sensing Compared with Traditional Sensing Technologies
(1) Higher Detection Accuracy and Reliability
Compared with traditional infrared sensing, radar sensing is not significantly affected by environmental factors such as light, temperature, and humidity. In the elevator of a dimly lit underground parking lot or in the hot and humid summer, infrared sensing may have misjudgments or detection blind spots. However, radar sensing, relying on the characteristics of electromagnetic waves, can still stably and accurately detect the target, ensuring that the elevator automatic sensing system is always in a reliable operating state. In the complex application scenarios of elevators in industrial plants, even if there is a large amount of electromagnetic interference generated by surrounding machinery and equipment, advanced radar sensors can effectively filter out interference signals through self-calibration functions and special anti-interference designs and accurately sense human activities.
(2) Broader Detection Range and Angle
Radar sensors have obvious advantages in terms of detection range and angle. For some radar products applied to elevators, the sensing distance can reach several meters, and the sensing angle can cover a large range both horizontally and in the pitch direction. This means that in the elevator area of a spacious hotel lobby or a large commercial center, the radar can comprehensively and without blind spots monitor the human activities in all corners. Compared with traditional sensing technologies with limited detection ranges, it greatly expands the effective coverage area of elevator automatic sensing, providing passengers with more comprehensive and timely services.
(3) Excellent Detection Ability for Stationary and Slightly Moving Targets
Traditional sensing technologies often struggle to detect stationary or slightly moving targets, while radar sensing performs excellently in this regard. Whether it is a passenger standing still at the door when the elevator door is about to close or a person in a slightly shaking state inside the car, the radar can accurately identify them, effectively avoiding potential safety hazards caused by undetected targets and ensuring the safety of people during the operation of the elevator. In places such as hospitals where the safety requirements for elevator operation are extremely high, the accurate detection ability of radar sensing for stationary and slightly moving targets provides a solid guarantee for the safe riding of special patients.
IV. Outlook on the Development Trends of Elevator Radar Sensing Technology
(1) Multi-sensor Fusion for More Intelligent Control
In the future, the elevator automatic sensing system will develop towards the direction of multi-sensor fusion. Radar sensing will work in coordination with cameras, ultrasonic sensors, etc., complementing each other with data information. The camera can be used to identify the passenger's identity and judge the behavior. The ultrasonic sensor can assist in detecting nearby objects. Combined with the data such as distance and speed obtained by the radar, a more comprehensive and accurate model of the elevator operation environment can be constructed to achieve more intelligent and humanized control of the elevator. For example, through multi-sensor fusion, the elevator can predict the passenger's intention to ride in advance and prepare the car before the passenger reaches the elevator door, further improving the riding efficiency.
(2) Application of Higher Frequency Band Radars to Improve Performance
With the progress of science and technology, radar technologies in higher frequency bands will gradually be applied to the elevator field. For example, radars in the 60GHz or even higher frequency bands have higher resolution and narrower beam widths, which can provide more accurate detection results, further improving the recognition accuracy of the elevator automatic sensing system for the position and actions of people. At the same time, it can reduce the volume and power consumption of radar equipment, making the design of the elevator system more compact and energy-efficient. In the high-speed elevators of super high-rise buildings, high-frequency band radars can better adapt to the complex working conditions brought about by high-speed operation and ensure the stable and reliable automatic sensing performance of the elevator during high-speed lifting and lowering.
(3) Integration with the Internet of Things to Create a Smart Elevator Ecosystem
In the era of the Internet of Things, elevator radar sensing technology will be deeply integrated into the Internet of Things system. Through the Internet of Things, the radar sensing data of each elevator can be uploaded to the cloud in real time to achieve remote monitoring and management. Property managers can understand the operation status of the elevator and the riding situation of people anytime and anywhere, and promptly discover and deal with potential faults. At the same time, based on big data analysis, the operation mode of the elevator can also be optimized and adjusted, such as reasonably arranging the elevator stopping strategy according to the passenger flow at different times, providing users with more convenient and efficient riding services, and constructing a comprehensive smart elevator ecosystem.
Radar sensing technology is, with its unique technical advantages, setting off a profound revolution in the field of elevator automatic sensing. From improving the safety and efficiency of elevator operation to enhancing the user's riding experience, the application value of radar sensing is continuously highlighted. With the continuous innovation and development of technology, it will surely inject a continuous stream of power into the intelligent upgrading of the elevator industry, promote the full arrival of the era of smart elevators, and make people's vertical travel safer, more convenient, and more comfortable.
