Escalator passenger fall detection apparatus and method based on microwave sensors

Abstract

The application discloses an escalator passenger falling detection device based on a microwave sensor, which comprises a microwave radar sensor and a falling discrimination controller; the microwave radar sensor is installed on the inner side plate of the escalator and is configured to detect the moving speed and direction of passengers in the coverage area by using the Doppler effect; the falling discrimination controller is configured to determine that a passenger falling event occurs when the rate of change of the downward moving speed of a human body exceeds a preset acceleration threshold, the moving direction is downward along the escalator, the moving speed exceeds a preset speed threshold, and the duration exceeds a preset minimum duration. The application does not collect passenger images, has no privacy controversy, and has low hardware cost; the sensor is installed on a fixed component, power supply and maintenance are simple; the Doppler effect and double thresholds are used to accurately discriminate falling, dust and water mist can be penetrated, environmental adaptability is high, and the escalator can be controlled in linkage to ensure passenger safety.

Description

Technical Field

[0001] This invention relates to the field of escalator safety technology, specifically to an escalator passenger fall detection device and method based on a microwave sensor. Background Technology

[0002] Escalators are widely used in public places such as shopping malls, train stations, and airports. Incidents of passengers falling while riding escalators due to instability, sudden illness, or loss of balance while carrying belongings are not common. If the escalator is not detected and stopped in time, fallen passengers may be crushed by subsequent steps or downstream passengers, causing secondary injuries.

[0003] Currently, existing technologies for escalator passenger fall detection mainly include the following categories: 1. Fall detection scheme based on computer vision / deep learning For example, patent document CN109726750B discloses a passenger fall detection device and method, which is based on image acquisition and processing, and determines whether a fall has occurred by analyzing changes in passenger posture through visual images. Another example is patent document CN108805093B, which discloses a deep learning-based method for detecting passenger falls on escalators, using a deep learning model to detect passenger fall behavior by acquiring video images of the escalator. Yet another example is patent document CN110472473A, which discloses a method for detecting falls on escalators based on posture estimation, using a human posture estimation algorithm to analyze the positions of key points on the human body and the trajectory of movement to detect falls.

[0004] The aforementioned vision-based solutions have the following drawbacks: they require the installation of high-definition cameras and the use of edge computing units to run image analysis algorithms, resulting in high hardware and deployment costs; they are greatly affected by environmental factors such as lighting conditions, occlusion, and angle, and lack robustness in outdoor or complex lighting escalator scenarios; the collection of passenger images raises privacy concerns; and they do not involve triggering the escalator control system to slow down or stop the escalator after detection.

[0005] 2. Scheme for installing vibration / pressure sensors in the ladder steps For example, patent document CN113916358B discloses a method for escalator hazard monitoring and response based on vibration signal analysis. This method involves setting up a data sampling device array on the escalator step treads to collect vertical vibration signals, using time-domain characteristic values ​​to determine if an object has fallen, and using frequency-domain characteristic values ​​to determine if a person has fallen. Another example is patent document CN107915111B, which discloses a passenger behavior monitoring method and device. This method monitors passenger behavior using pressure sensors installed on the inner wall of the escalator step surface and infrared sensors on both sides of the step surface.

[0006] The sensors in the above-mentioned scheme are installed on the step treads or kick plates, which are moving parts in a cyclic motion. They require independent power supply and wireless communication for each step, resulting in high system complexity and difficult maintenance. The vibration signals are easily interfered with by the mechanical vibration of the escalator itself, leading to a high false alarm rate. Furthermore, it only focuses on behavior monitoring and visual warnings, without addressing the control of escalator deceleration / stop after a fall.

[0007] 3. Passenger detection scheme based on infrared physical sensors For example, patent document CN104058325A discloses an escalator safety warning system that uses through-beam infrared sensors installed on both sides of the escalator. When a passenger enters, the infrared beam is blocked, and the system detects the passenger's presence and issues a warning. Another example is Korean patent document KR102308850B1, which discloses a safety operation control device for escalators and moving walkways. Infrared sensors are installed facing each other on the lower part of the handrails on both sides of the escalator exit side. Combined with a load sensor, the escalator's operating speed is controlled based on the detection results.

[0008] The above solution uses through-beam infrared sensors to detect the presence of passengers (binary detection), which cannot identify changes in posture such as passengers falling; the infrared sensors are only installed at the exit to detect the passengers' descent, not for full-time monitoring; and they do not have fall recognition functionality. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a device and method for detecting passenger falls on escalators based on microwave sensors, which, without collecting passenger images or privacy disputes, uses the Doppler effect to accurately detect sudden changes in the speed and direction of human movement (downward acceleration) to determine a fall. It has strong environmental adaptability (can penetrate dust and water mist) and can be linked with the escalator control system to achieve deceleration and stopping.

[0010] To solve the above-mentioned technical problems, the present invention provides an escalator passenger fall detection device based on a microwave sensor, comprising: a microwave radar sensor and a fall detection controller; the microwave radar sensor is installed on the inner side plate of the escalator and is configured to detect the movement speed and movement direction of passengers within the coverage area using the Doppler effect; The fall detection controller is electrically connected to the microwave radar sensor and is configured to: receive the motion speed and motion direction signals output by the microwave radar sensor; when the rate of change of the downward motion speed of a human body exceeds a preset acceleration threshold (a_th), the motion direction is downward along the escalator, the motion speed exceeds a preset speed threshold (V_th), and the duration exceeds a preset minimum duration (T_min), a passenger fall event is determined to have occurred.

[0011] Preferably, the microwave radar sensor operates at a frequency of 24 GHz or 5.8 GHz, the coverage distance of a single microwave radar sensor is 1 m to 3 m, and the distance between two adjacent microwave radar sensors along the escalator's running direction is approximately 2 m.

[0012] Preferably, the preset acceleration threshold (a_th) is ≥1 m / s², the preset velocity threshold (V_th) is >0.5 m / s and greater than the step running speed, and the preset minimum duration (T_min) is 0.3 s.

[0013] Preferably, it also includes an audible and visual alarm device, which is connected to the fall detection controller and is triggered by the fall detection controller when a passenger fall event is detected.

[0014] Preferably, the fall detection controller is connected to the escalator control system and is configured to issue a deceleration and stop command to the escalator control system after a fall event is detected, so that the escalator control system controls the main drive motor to decelerate and brake according to a preset deceleration curve through the frequency converter.

[0015] The present invention also provides a method for detecting passenger falls on escalators based on microwave sensors, comprising the following steps: Step S1: Install a microwave radar sensor on the inner side panel of the escalator; Step S2: Continuously detect the speed and direction of movement of passengers within the coverage area using the Doppler effect; Step S3: When the rate of change of the downward movement speed of a human body exceeds the preset acceleration threshold (a_th), the movement direction is downward along the escalator, the movement speed exceeds the preset speed threshold (V_th), and the duration exceeds the preset minimum duration (T_min), a passenger fall event is determined to have occurred. Step S4: After determining that a fall has occurred, a deceleration and stop command is sent to the escalator control system to control the escalator to decelerate and stop.

[0016] Preferably, the microwave radar sensor operates at a frequency of 24GHz or 5.8GHz, and the coverage distance of a single microwave radar sensor is 1m to 3m. A microwave radar sensor is installed approximately every 2m along the direction of escalator operation.

[0017] Preferably, the preset acceleration threshold (a_th) is ≥1 m / s², the preset velocity threshold (V_th) is >0.5 m / s and greater than the step running speed, and the preset minimum duration (T_min) is 0.3 s.

[0018] Preferably, in step S4, the escalator control system controls the main drive motor to decelerate according to an S-shaped deceleration curve via a frequency converter, with the deceleration rate not exceeding 1.0 m / s². After decelerating to a low speed, the working brake is activated to bring the escalator to a complete stop.

[0019] Preferably, in step S4, the audible and visual alarm and voice alarm are activated simultaneously with the deceleration and elevator stop command.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. Low cost and no privacy concerns: Using microwave radar sensors instead of cameras, it does not collect passenger images, thus avoiding privacy concerns. The hardware cost is significantly lower than that of visual AI solutions, and there is no need to equip it with edge computing devices.

[0021] 2. Fixed components are easy to install and maintain: The sensor is installed on the inner side plate (fixed component) of the escalator and can be directly powered by a fixed line and wired communication. There is no need to solve the problem of independent power supply and wireless communication for the moving steps. The system has low complexity and is easy to maintain.

[0022] 3. Accurate fall detection based on the Doppler effect: The Doppler effect is used to detect sudden changes in the speed and direction of human movement (downward acceleration), which has a clear physical basis; dual discrimination conditions of velocity threshold V_th and acceleration threshold a_th are set to reduce false alarms caused by normal passenger movements while ensuring detection sensitivity.

[0023] 4. Strong environmental adaptability: Microwave sensors have the ability to penetrate dust and water mist, are not affected by light conditions, and are suitable for various complex operating environments such as outdoor, underground passages, and humid environments.

[0024] 5. Fewer sensors and easier installation: A single microwave radar sensor covers a distance of 1m to 3m, and one sensor can be installed every 2m to achieve full coverage. The number of sensors is less than that of the through-beam sensor solution, making installation simpler.

[0025] 6. Interlocking escalator control ensures safety: Upon detecting a fall, the escalator control system is immediately activated to decelerate and stop the escalator in an S-shaped deceleration curve, while simultaneously activating audible and visual alarms and voice warnings to prevent secondary injuries. Detailed Implementation

[0026] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can fully understand other advantages and technical effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and the details in this specification can also be applied based on different viewpoints, with various modifications or changes made without departing from the overall design concept of the invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. The following exemplary embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the specific embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary embodiments to those skilled in the art. Example

[0027] This embodiment provides an escalator passenger fall detection device based on a microwave sensor, including a microwave radar sensor and a fall detection controller.

[0028] The microwave radar sensor is installed on the inner side panel of the escalator and is configured to detect the speed and direction of movement of passengers within the coverage area using the Doppler effect. Furthermore, the microwave radar sensor operates at a frequency of 24GHz or 5.8GHz, with a coverage distance of 1m to 3m for a single sensor and a spacing of approximately 2m between two adjacent sensors along the escalator's running direction. In this embodiment, the microwave radar sensor operates at 24GHz (or the commonly used 5.8GHz band), with a coverage distance of approximately 2m to 3m for a single sensor. Installing one sensor approximately every 2m along the escalator's running direction achieves full coverage. The microwave radar sensor is powered by a fixed line and communicates with the fall detection controller via a wired connection, eliminating the need for independent power supply and wireless communication for the moving steps.

[0029] The fall detection controller is electrically connected to the microwave radar sensor and is configured as follows: • Receives motion speed and direction signals output by microwave radar sensor 5; • When the rate of change of a person's downward movement speed exceeds the preset acceleration threshold a_th, the movement direction is downward along the escalator, the movement speed exceeds the preset speed threshold V_th, and the duration exceeds the preset minimum duration T_min, a passenger fall event is determined to have occurred.

[0030] Furthermore, the preset acceleration threshold a_th ≥ 1 m / s², the preset velocity threshold V_th > 0.5 m / s and is greater than the step-level running speed, and the preset minimum duration T_min is 0.3 s. In this embodiment, a_th = 1 m / s², V_th = 0.5 m / s (greater than the step-level running speed), and T_min = 0.3 s.

[0031] The fall detection controller is configured to: when a passenger is standing normally while riding the escalator, identify that their movement speed is close to the escalator's operating speed, and use this as a benchmark to determine whether the passenger is accelerating downwards.

[0032] The device also includes an audible and visual alarm device connected to the fall detection controller, which is triggered by the fall detection controller when a passenger fall event is detected. In this embodiment, the audible and visual alarm device includes a warning light and a speaker, which can issue audible and visual alarms and voice warnings (such as "Emergency, the escalator is about to slow down").

[0033] The fall detection controller is connected to the escalator control system and is configured to issue a deceleration and stop command to the escalator control system after detecting a fall event. This causes the escalator control system to control the main drive motor to decelerate and brake according to a preset deceleration curve via a frequency converter. In this embodiment, the escalator control system controls the main drive motor to decelerate according to an S-shaped deceleration curve via a frequency converter, with a deceleration rate not exceeding 1.0 m / s². After the frequency converter decelerates to a low speed, the working brake activates, completely stopping the escalator. After stopping, the escalator enters a locked state, requiring maintenance personnel to confirm safety on-site and manually reset it before operation can resume.

[0034] Working principle of the device When a passenger is standing normally on the escalator, their body moves along with the steps at the escalator's running speed. The radial velocity detected by the microwave radar sensor is close to zero or the same as the step speed (reference state). When a passenger falls, their body accelerates downward relative to the escalator. The microwave radar sensor detects a sudden increase in the body's velocity and its downward direction based on the Doppler effect.

[0035] To avoid misjudging normal actions such as bending over or turning around as falls, this invention sets up a triple discrimination condition: an acceleration threshold a_th, a velocity threshold V_th, and a minimum duration T_min, which must be met simultaneously to determine a fall, effectively reducing the false alarm rate. Example

[0036] This embodiment provides a method for detecting passenger falls on escalators based on microwave sensors, including the following steps: Step S1: Install microwave radar sensor 5 on the inner side panel 1 of the escalator.

[0037] Furthermore, the operating frequency of the microwave radar sensor is selected as 24GHz or 5.8GHz, the coverage distance of a single microwave radar sensor 5 is 1m to 3m, and a microwave radar sensor 5 is installed approximately every 2m along the running direction of the escalator. In this embodiment, the operating frequency is selected as 24GHz, the coverage distance of a single sensor is approximately 2m to 3m, and one sensor is installed approximately every 2m along the running direction.

[0038] Step S2: Continuously detect the speed and direction of movement of passengers within the coverage area using the Doppler effect.

[0039] When passengers are standing and riding the escalator normally, the system detects that the passenger's movement speed along the escalator's direction of travel is close to the escalator's operating speed (typically about 0.5 m / s), and the radial relative movement speed is close to zero. This is used as the baseline state.

[0040] Step S3: When the rate of change of the downward movement speed of the human body exceeds the preset acceleration threshold a_th, the movement direction is downward along the escalator, the movement speed exceeds the preset speed threshold V_th, and the duration exceeds the preset minimum duration T_min, a passenger fall event is determined to have occurred.

[0041] Furthermore, the preset acceleration threshold a_th ≥ 1 m / s², the preset velocity threshold V_th > 0.5 m / s and is greater than the step-by-step running speed, and the preset minimum duration T_min is 0.3 s. In this embodiment, a_th = 1 m / s², V_th = 0.5 m / s, and T_min = 0.3 s.

[0042] The fall detection controller analyzes the signals output by the microwave radar sensor in real time: • When a sudden increase in the downward motion speed of the human body is detected, the rate of change of velocity (acceleration) exceeds the preset threshold a_th=1 m / s²; • And the direction of movement is downward along the escalator; • And the speed of movement V > V_th = 0.5 m / s (greater than the speed of the steps); • And the duration exceeds T_min=0.3s; If all of the above conditions are met, it is determined to be a passenger fall incident.

[0043] To avoid misclassifying normal passenger movements such as bending over or turning as falls, this step sets up three criteria: a velocity threshold V_th filters out cases with no significant downward movement; an acceleration threshold a_th filters out slow movements; and a minimum duration T_min filters out instantaneous movements. A fall is only determined when all three criteria are met, effectively reducing the false alarm rate.

[0044] Step S4: After determining that a fall has occurred, a deceleration and stop command is sent to the escalator control system to control the escalator to decelerate and stop.

[0045] Furthermore, in step S4, the escalator control system controls the main drive motor to decelerate according to an S-shaped deceleration curve via a frequency converter. The deceleration rate does not exceed 1.0 m / s². After decelerating to a low speed, the working brake is activated to bring the escalator to a complete stop.

[0046] Furthermore, in step S4, while issuing the deceleration and elevator stop command, the audible and visual alarm and voice alarm are activated.

[0047] In this embodiment, upon confirmation of a fall, the fall detection controller sends a deceleration and stop command to the escalator control system, triggering an audible and visual alarm, frequency converter deceleration, and automatic braking. The escalator control system uses a frequency converter to control the main drive motor to decelerate according to an S-shaped deceleration curve, with a deceleration rate not exceeding 1.0 m / s². After decelerating to a low speed, the working brake engages, completely stopping the escalator. After stopping, the escalator enters a locked state, requiring on-site safety confirmation and manual reset by maintenance personnel before operation can resume. Simultaneously with issuing the deceleration and stop command, an audible and visual alarm and a voice warning (such as "Emergency situation, escalator is about to decelerate") are activated.

[0048] The present invention has been described in detail above through specific embodiments and examples, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A microwave sensor-based escalator passenger fall detection device, characterized in that, include: Microwave radar sensor and fall detection controller; The microwave radar sensor is installed on the inner side panel of the escalator and is configured to detect the speed and direction of movement of passengers within the coverage area using the Doppler effect. The fall detection controller is electrically connected to the microwave radar sensor and is configured to: receive the motion speed and motion direction signals output by the microwave radar sensor; when the rate of change of the downward motion speed of a human body exceeds a preset acceleration threshold (a_th), the motion direction is downward along the escalator, the motion speed exceeds a preset speed threshold (V_th), and the duration exceeds a preset minimum duration (T_min), a passenger fall event is determined to have occurred.

2. The escalator passenger fall detection device based on a microwave sensor according to claim 1, characterized in that, The microwave radar sensor operates at a frequency of 24 GHz or 5.8 GHz, and the coverage distance of a single microwave radar sensor is 1 m to 3 m. The distance between two adjacent microwave radar sensors along the direction of escalator operation is approximately 2 m.

3. The escalator passenger fall detection device based on a microwave sensor according to claim 1, characterized in that, The preset acceleration threshold (a_th) is ≥1 m / s², the preset velocity threshold (V_th) is >0.5 m / s and greater than the step running speed, and the preset minimum duration (T_min) is 0.3s.

4. The escalator passenger fall detection device based on a microwave sensor according to claim 1, characterized in that, It also includes an audible and visual alarm device, which is connected to the fall detection controller and is triggered by the fall detection controller when a passenger fall event is detected.

5. The escalator passenger fall detection device based on a microwave sensor according to claim 1, characterized in that, The fall detection controller is connected to the escalator control system and is configured to send a deceleration and stop command to the escalator control system after a fall event is detected, so that the escalator control system controls the main drive motor to decelerate and brake according to a preset deceleration curve through the frequency converter.

6. A method for detecting passenger falls on escalators based on microwave sensors, characterized in that, Includes the following steps: Step S1: Install a microwave radar sensor on the inner side panel of the escalator; Step S2: Continuously detect the speed and direction of movement of passengers within the coverage area using the Doppler effect; Step S3: When the rate of change of the downward movement speed of a human body exceeds the preset acceleration threshold (a_th), the movement direction is downward along the escalator, the movement speed exceeds the preset speed threshold (V_th), and the duration exceeds the preset minimum duration (T_min), a passenger fall event is determined to have occurred. Step S4: After determining that a fall has occurred, a deceleration and stop command is sent to the escalator control system to control the escalator to decelerate and stop.

7. The method for detecting passenger falls on escalators based on microwave sensors according to claim 6, characterized in that, The microwave radar sensor operates at a frequency of 24GHz or 5.8GHz. The coverage distance of a single microwave radar sensor is 1m to 3m. A microwave radar sensor is installed approximately every 2m along the direction of escalator operation.

8. The method for detecting passenger falls on escalators based on microwave sensors according to claim 6, characterized in that, The preset acceleration threshold (a_th) is ≥1 m / s², the preset velocity threshold (V_th) is >0.5 m / s and greater than the step running speed, and the preset minimum duration (T_min) is 0.3s.

9. The method for detecting passenger falls on escalators based on microwave sensors according to claim 6, characterized in that, In step S4, the escalator control system controls the main drive motor to decelerate according to an S-shaped deceleration curve via a frequency converter. The deceleration rate does not exceed 1.0 m / s². After decelerating to a low speed, the working brake is activated to bring the escalator to a complete stop.

10. The method for detecting passenger falls on escalators based on microwave sensors according to claim 6, characterized in that, In step S4, the audible and visual alarm and voice alarm are activated simultaneously with the deceleration and elevator stop command.