CN106081776B - The method, apparatus and system of elevator safety monitoring - Google Patents

Abstract

The invention relates to a method, device and system for elevator safety monitoring. The method includes: controlling a preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receiving electromagnetic radiation reflected by objects; calculating the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and according to the phase difference Obtaining the current depth information between the detection device and the object; comparing the depth information with a preset safety depth, and judging whether an unsafe behavior occurs in the target monitoring area according to the comparison result. The invention can effectively detect whether passengers touch or lean against the target monitoring area, thereby facilitating timely dangerous emergency treatment and preventing elevator accidents.

Description

Method, device and system for elevator safety monitoring

technical field

The invention relates to the technical field of elevators, in particular to a method, device and system for elevator safety monitoring.

Background technique

At present, elevators are widely used in people's lives, and elevator safety is becoming more and more important. During the lifting process of the elevator or the opening and closing of the car door, passengers often have unsafe behaviors such as clinging, touching, leaning on the elevator door, or even kicking the elevator door. These behaviors are likely to lead to elevator accidents However, the current elevators are unable to control these unsafe behaviors, so there are great potential safety hazards.

Contents of the invention

Based on this, the embodiments of the present invention provide a method, device and system for elevator safety monitoring, which can effectively detect unsafe behavior of passengers and perform corresponding elevator operation control.

One aspect of the present invention provides a method for elevator safety monitoring, including:

Control the preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected by the object;

calculating the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and obtaining current depth information between the detection device and the object according to the phase difference;

Comparing the depth information with a preset safe depth, and judging whether an unsafe behavior occurs in the target monitoring area according to the comparison result;

Wherein, the safety depth is: the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area.

Another aspect of the present invention provides a device for elevator safety monitoring, including:

The transceiver control module is used to control the preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected by the object;

The detection depth calculation module is used to calculate the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and obtain the current depth information between the detection device and the object according to the phase difference;

A judging module, configured to compare the depth information with a preset safe depth, and judge whether an unsafe behavior occurs in the target monitoring area according to the comparison result;

Wherein, the safety depth is the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area.

Another aspect of the present invention also provides an elevator safety monitoring system, including an elevator main control, and a detection device arranged on the top of the car, and the detection device is connected to the elevator main control;

said detection device is capable of emitting and receiving electromagnetic radiation;

The main control of the elevator can control the detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected back by the object; calculate the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and according to the phase difference Obtaining the current depth information between the detection device and the object; and comparing the depth information with a preset safety depth, and judging whether an unsafe behavior occurs in the target monitoring area according to the comparison result;

Wherein, the safety depth is: the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area.

In the above technical solution, by controlling the preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receiving the electromagnetic radiation reflected back by the object, the target monitoring can be judged based on the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation. Whether an unsafe act has occurred in the area. The invention can effectively detect whether unsafe behavior occurs in the target monitoring area in the elevator, facilitates timely dangerous emergency response, and prevents elevator accidents.

Description of drawings

Fig. 1 is a schematic flow chart of a method for elevator safety monitoring of an embodiment;

Fig. 2 is a schematic diagram of the effective detection area of the detection device in a preferred embodiment;

Fig. 3 is a schematic diagram of the effective detection area of the detection device when no unsafe behavior occurs;

Fig. 4 is a schematic diagram of the effective detection area of the detection device when an unsafe behavior occurs;

Figure 5 is a schematic diagram of emergency response when opening and closing the door;

Fig. 6 is a schematic flow chart of the safety monitoring method in the elevator door opening process of an embodiment;

Fig. 7 is a schematic flow chart of the safety monitoring method in the elevator door closing process of an embodiment;

Fig. 8 is a schematic structural diagram of an elevator safety monitoring device in an embodiment;

Fig. 9 is a schematic structural diagram of an elevator safety monitoring system according to an embodiment.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Fig. 1 is a schematic flow chart of a method for elevator safety monitoring in an embodiment; in this embodiment, the method is applied to the elevator main control as an example for illustration, and of course it can also be applied to the control connected with the elevator main control device.

As shown in Figure 1, the method for elevator safety monitoring in the present embodiment comprises steps:

S11, controlling the preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receiving the electromagnetic radiation reflected back by the object;

Preferably, the target monitoring area is the car door area (of course, according to actual needs, the solution of the present invention can also be used to monitor the car side wall area). The preset detection device can be a TOF (Time of Flight, time of flight) detector, as shown in Figure 2, the TOF detector is installed on the top of the elevator car, and its detection area in the car space is a quadrangular pyramid , as shown in Figure 2, the shaded area is the detection area 4. Since the dimensions of the car and the ground are fixed, the background of the depth information of the car door area detected by the TOF detector is fixed.

It can be understood that the depth information can be understood as: the distance information between the TOF detector and the point of reflected electromagnetic radiation in the detection area 4; if there is no obstacle, that is, the TOF detector and the detection The distance information between the points on the car door reflecting electromagnetic radiation in the area 4 certainly includes the distance information between the TOF detector and the points on the car floor reflecting electromagnetic radiation in the detection area 4 .

S12. Calculate the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and obtain current depth information between the detection device and the object according to the phase difference;

In Figures 2 to 4, mark 1 marks the top of the car door frame, mark 2 marks the distance between the TOF sensor lens and the car door, mark 3 marks the TOF detector device, mark 4 marks the TOF detection area, and mark 5 The sign is the car door, the sign 6 is the direction of the entrance and exit door, the sign 7 is the passenger, the sign 8 is the car, the sign 9 is the direction of the elevator, and the sign 10 is the hoisting traction machine. Mark 11 marks the controller used to control the lift, mark 12 marks the controller for opening and closing the door, mark 13 marks the motor of the controller for opening and closing the door, mark 14 marks the hall door, mark 15 marks the The top of the landing door frame, mark 16 marks the direction of opening and closing the door, mark 17 marks the obstacle, mark 18 marks the distance h1 between the obstacle and the side of the car door frame, and mark 19 marks the vertical distance between the obstacle and the closed door. The distance h2 between the lines (in the case of closing the door in the middle). With reference to Figures 2 to 4, unsafe behaviors such as touching, leaning on the elevator door, and TOF detectors are similar in any position in the door opening and closing direction 16 . In order to facilitate the description of the problem, Figure 3 and Figure 4 illustrate a two-dimensional section in the direction of the door width. Figure 3 shows the detection area of the TOF detector when the car door is completely closed, and the detection areas 4.1 to 4.3 represent the spatial area that the TOF detector can detect in the door-entry direction 6 . When the concern is to prevent passengers from touching, leaning on car doors and other unsafe behaviors, the detection area 4.1 is the target monitoring area of the present invention.

S13, comparing the depth information with a preset safety depth, and judging whether unsafe behaviors occur in the target monitoring area according to the comparison result;

As shown in Figure 3, when no obstacle is in the target monitoring area, the depth information between the detection device and each point on the car door (the car door area corresponding to area 4.1) is fixed, and can be obtained The minimum depth between the detection device and the car door is taken as the safety depth. As shown in Fig. 4, when there is an obstacle in the target monitoring area 4.1, the electromagnetic radiation is actually reflected by the obstacle, and the depth between the detection device and the obstacle must be smaller than the safety depth.

During the process of opening and closing the car door, the depth information of the image corresponding to the area 4.1 may change. When the car door is completely closed, the depth information of the image corresponding to the area 4.1 is the minimum value that can ensure safety. Determine safe depth. That is, when the actually obtained depth information is less than the minimum value, it means that there are obstacles in the area 4.1, regardless of the position of the car door. This minimum value can be obtained by recording the first frame of image when the car door is completely closed and there is no obstacle in area 4.1.

If the depth information is less than the safe depth, it is judged that there is an obstacle in the target monitoring area, and an unsafe behavior occurs in the target monitoring area; if the depth information is equal to the safe depth, it is judged that there is no obstacle in the target monitoring area. The target monitoring area, where no unsafe behavior occurs in the target monitoring area. Further, the detection result is transmitted to the door machine controller 12 or the elevator main controller 11, and corresponding emergency response can be carried out according to the different working conditions of the elevator, including outputting preset alarm prompt information, controlling the elevator to stop the lifting operation etc.; thereby avoiding the occurrence of elevator accidents. Wherein, the door machine controller 12 is used to control the door opening/closing of the elevator, and the elevator main controller 11 is used to control the lifting and lowering of the elevator and floor display and the like.

As a preferred embodiment, in the process of opening and closing the car door, if there is an obstacle close to the car door, the elevator safety monitoring method of the present invention can further detect, and make a corresponding emergency response according to the detection result , including:

1) The state of the door opening process, as shown in Figure 6.

S21. When it is judged that there is an obstacle in the target monitoring area, further obtain the current running state of the elevator; if the current state is the door opening process, obtain the distance h1 between the obstacle and the car door frame;

It can be understood that if the car door is opened from the middle to both sides, h1 is as shown in Figure 5; if the car door moves to the left to open the door, h1 is the distance from the obstacle to the door frame ( That is, the distance from the left door frame); if the car door moves to the right to open the door, h1 is the distance from the obstacle to the door opening (ie, the right door frame).

S22. Detect whether the distance h1 is less than or equal to a preset first distance threshold, if yes, perform step S23, if not, perform step S24, and detect whether the distance h1 is less than or equal to a preset second distance threshold;

Step S23, control the elevator to execute the preset first door-opening emergency plan, and end.

In the embodiment of the present invention, if it is the first door-opening emergency solution, the elevator is controlled to stop the door-opening action, and a corresponding voice alarm prompt is output;

Step S24, detecting whether the distance h1 is less than or equal to a preset second distance threshold; the second distance threshold is greater than the first distance threshold; if it is less than or equal to the preset second distance threshold, perform step S25; otherwise, Execute step S26.

S25, controlling the elevator to execute the preset second door-opening emergency plan, and ending.

In the embodiment of the present invention, if it is the second door-opening emergency solution, the elevator is controlled to slow down the door-opening action, and a corresponding voice alarm prompt is output.

S26, control the elevator to execute the preset third door opening emergency plan, and end.

In the embodiment of the present invention, if it is the third door-opening emergency solution, the door-opening action of the elevator is not changed, and a corresponding voice alarm prompt is output, so as to avoid affecting passengers' use of the elevator.

Through the above-mentioned door opening emergency solution, accidents such as passengers leaning against the elevator door frame during the door opening process, causing clothing, hair, etc. to be caught in the elevator door frame by the door opening action, can be prevented.

2) The state of the door closing process, as shown in Figure 7.

S31. When it is judged that there is an obstacle in the target monitoring area, further obtain the current running state of the elevator; if it is currently in the door closing process state, then obtain the vertical line 20 when the obstacle and the car door are fully closed The distance h2;

If the car door is closed from both sides to the middle, h2 is as shown in Figure 5; if the car door moves to the left to close the door, h2 is the distance from the obstacle to the door frame (that is, the left door frame) If the car door moves to the right to close the door, h2 is the distance between the obstacle and the door frame (that is, the right door frame) that closes the door in place.

S32. Detect whether the distance h2 is less than or equal to a preset third distance threshold, if yes, perform step S33, if not, perform step S34;

Step S33, control the elevator to execute the preset first door-closing emergency plan, and end.

In the embodiment of the present invention, if it is the first door-closing emergency solution, the elevator is controlled to stop the door-closing action, and a corresponding voice alarm prompt is output;

Step S34, detecting whether the distance h2 is less than or equal to a preset fourth distance threshold; the fourth distance threshold is greater than the third distance threshold; if it is less than or equal to the preset fourth distance threshold, execute step S35; otherwise, Execute step S36.

S35, control the elevator to execute the preset second door closing emergency plan, and end.

In the embodiment of the present invention, if it is the second door-closing emergency solution, the elevator is controlled to slow down the door-closing action, and a corresponding voice alarm prompt is output.

S36, control the elevator to execute the preset third door closing emergency plan, and end.

In the embodiment of the present invention, if it is the third door-closing emergency solution, the door-closing action of the elevator is not changed, and a corresponding voice alarm prompt is output, so as to avoid affecting passengers' use of the elevator.

In addition, if it is determined that there is an obstacle in the target monitoring area, and it is determined that the car door has been fully closed, the elevator is prohibited from moving up and down, and a voice warning is given to avoid the situation that the car door is sandwiched by the obstacle.

It should be noted that for the foregoing method embodiments, for the sake of simplicity of description, they are expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because Certain steps may be performed in other orders or simultaneously in accordance with the present invention.

Based on the same idea as the elevator safety monitoring method in the above embodiments, the present invention also provides an elevator safety monitoring device, which can be used to implement the above elevator safety monitoring method. For the convenience of description, in the schematic structural diagram of the embodiment of the elevator safety monitoring device, only the parts related to the embodiment of the present invention are shown. Those skilled in the art can understand that the illustrated structure does not constitute a limitation on the device, and may include More or fewer components are shown, or some components are combined, or different component arrangements are shown.

Fig. 8 is a schematic structural diagram of an elevator safety monitoring device according to an embodiment of the present invention, and the device can be applied to an elevator main control or a controller connected to an elevator main control. As shown in Figure 8, the device for elevator safety monitoring of the present embodiment includes: transceiver control module 310, detection depth calculation module 320, and judgment module 330, each module is described in detail as follows:

The transceiver control module 310 is used to control the preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected by the object;

Preferably, the target monitoring area is the car door area (of course, according to actual needs, the solution of the present invention can also be used to monitor the car side wall area). The preset detection device may be a TOF (Time of Flight, time of flight) detector.

The detection depth calculation module 320 is used to calculate the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and obtain the current depth information between the detection device and the object according to the phase difference;

It can be understood in conjunction with the accompanying drawings that the depth information can be understood as: the distance information between the TOF detector and the point of reflection of electromagnetic radiation in the detection area 4; if there is no obstacle, the TOF detector and the The distance information between the points on the car door reflecting electromagnetic radiation in the detection area 4 certainly includes the distance information between the TOF detector and the points on the car floor reflecting electromagnetic radiation in the detection area 4 .

The judging module 330 is configured to compare the depth information with a preset safe depth, and judge whether an unsafe behavior occurs in the target monitoring area according to the comparison result;

Wherein, the safety depth is the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area.

Preferably, the elevator safety monitoring device further includes an emergency response module (not shown in FIG. 8 ), which is used to control the output of preset alarm prompt information if an unsafe behavior occurs in the target monitoring area; and/or , control the elevator to stop the lifting operation, and/or, control the elevator to stop or slow down the door opening/closing process.

Further, the emergency response module may also include:

The first emergency response unit is used to obtain the current running state of the elevator, and if it is currently in the state of the door opening process, then obtain the distance h1 between the obstacle and the side of the car door frame;

Detecting whether the distance h1 is less than or equal to a preset first distance threshold, if so, controlling the elevator to execute a preset first door opening emergency plan, if not, detecting whether the distance h1 is less than or equal to a preset second distance threshold; The second distance threshold is greater than the first distance threshold; if it is less than or equal to the second distance threshold, the elevator is controlled to execute the second preset door-opening emergency plan, otherwise, the elevator is controlled to execute the preset third door-opening emergency plan.

And, the second emergency response unit is used to obtain the current running state of the elevator, if the current state is the door closing process, then obtain the distance h2 between the obstacle and the vertical line when the car door is fully closed;

Detecting whether the distance h2 is less than or equal to the preset third distance threshold, if so, controlling the elevator to execute the preset first door closing emergency plan, if not, detecting whether the distance h2 is less than or equal to the preset fourth distance threshold, and The fourth distance threshold is greater than the third distance threshold; if it is less than or equal to the fourth distance threshold, the elevator is controlled to execute the second preset door closing emergency plan, otherwise, the elevator is controlled to execute the third preset door closing emergency plan.

Fig. 9 is a schematic structural diagram of an elevator safety monitoring system according to an embodiment of the present invention. As shown in Fig. 9, the elevator safety monitoring system of this embodiment includes an elevator master control 101, and also includes a detection system arranged on the top of the car. device 102, the detection device 101 is connected to the elevator master control 101.

Wherein, the detecting device 102 is capable of emitting and receiving electromagnetic radiation. Wherein, the elevator main control 101 can control the detection device 102 to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected by the object; calculate the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, according to The phase difference obtains the current depth information between the detection device and the object; and compares the depth information with a preset safety depth, and judges whether an error occurs in the target monitoring area according to the comparison result. safe behavior. In the embodiment of the present invention, the safety depth is the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area.

Preferably, the elevator safety monitoring system further includes a door machine controller connected to the elevator main control, so as to control the elevator to stop or slow down the door opening/closing process after detecting unsafe behavior in the target monitoring area.

It should be noted that, in the implementation of the elevator safety monitoring device of the above example, the information interaction and execution process between the modules/units are based on the same concept as the foregoing method embodiment of the present invention, and the technology brought by it The effects are the same as those of the foregoing method embodiments of the present invention, and for specific content, please refer to the descriptions in the method embodiments of the present invention, which will not be repeated here.

In addition, in the implementation of the elevator safety monitoring device in the above example, the logical division of each functional module is only an example. The above function allocation is accomplished by different functional modules, that is, the internal structure of the elevator safety monitoring device is divided into different functional modules to complete all or part of the functions described above. Each function module can be implemented in the form of hardware or in the form of software function modules.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above-mentioned embodiments can be completed by instructing related hardware through computer programs, and the programs can be stored in a computer-readable storage medium as independent product sale or use. When the program is executed, all or part of the steps in the embodiments of the above-mentioned methods can be executed. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM) or a random access memory (Random Access Memory, RAM) and the like.

In the foregoing embodiments, the descriptions of each embodiment have their own emphases, and for parts not described in detail in a certain embodiment, reference may be made to relevant descriptions of other embodiments. It can be understood that the terms "first", "second", etc. used herein are used to distinguish objects, but these objects are not limited by these terms.

The above-mentioned embodiments only express several implementation modes of the present invention, and should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. A method for elevator safety monitoring, characterized in that, comprising: Control the preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected by the object; calculating the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and obtaining depth information between the detection device and the object according to the phase difference; Comparing the depth information with a preset safe depth, and judging whether an unsafe behavior occurs in the target monitoring area according to the comparison result; Wherein, the safety depth is: the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area. 2. The method for elevator safety monitoring according to claim 1, wherein the target monitoring area is a car door area or a car side wall area. 3. The method for elevator safety monitoring according to claim 2, wherein the step of judging whether an unsafe behavior occurs in the target monitoring area according to the comparison result comprises: If the depth information is less than the safe depth, it is judged that there is an obstacle in the target monitoring area, and an unsafe behavior occurs in the target monitoring area; if the depth information is equal to the safe depth, it is judged that there is no obstacle in the target monitoring area. The target monitoring area, where no unsafe behavior occurs in the target monitoring area. 4. The method for elevator safety monitoring according to claim 3, characterized in that, after the step of judging that an unsafe behavior occurs in the target monitoring area, it also includes: Control the alarm device to output preset alarm prompt information; And/or, control the elevator to stop the lifting operation; And/or, control the elevator to stop or slow down the door opening/closing process. 5. The method for elevator safety monitoring according to claim 3, characterized in that, after judging that there is an obstacle in the target monitoring area, the step of unsafe behavior occurring in the target monitoring area also includes: Obtain the current running state of the elevator, if the current state is the door opening process, then obtain the distance h1 between the obstacle and the car door frame; Detecting whether the distance h1 is less than or equal to a preset first distance threshold, if so, controlling the elevator to execute a preset first door opening emergency plan, if not, detecting whether the distance h1 is less than or equal to a preset second distance threshold; the second distance threshold is greater than the first distance threshold; If it is less than or equal to the second distance threshold, the elevator is controlled to execute the second preset door opening emergency plan; otherwise, the elevator is controlled to execute the third preset door opening emergency plan. 6. The method for elevator safety monitoring according to claim 5, wherein the step of controlling the elevator to execute the preset first door-opening emergency plan/second door-opening emergency plan/third door-opening emergency plan comprises: If it is the first door-opening emergency plan, control the elevator to stop the door-opening action, and output the corresponding voice alarm prompt; If it is the second door-opening emergency plan, control the elevator to slow down the door-opening action, and output the corresponding voice alarm prompt; If it is the third door-opening emergency solution, the door-opening action of the elevator is not changed, and a corresponding voice alarm prompt is output. 7. The method for elevator safety monitoring according to claim 3, characterized in that, after judging that there is an obstacle in the target monitoring area, the step of unsafe behavior occurring in the target monitoring area also includes: Obtain the current running state of the elevator, if it is currently in the door closing process state, then obtain the distance h2 between the obstacle and the vertical line when the car door is fully closed; Detecting whether the distance h2 is less than or equal to the preset third distance threshold, if so, controlling the elevator to execute the preset first door closing emergency plan, if not, detecting whether the distance h2 is less than or equal to the preset fourth distance threshold; the fourth distance threshold is greater than the third distance threshold; If it is less than or equal to the fourth distance threshold, the elevator is controlled to implement the second preset door closing emergency plan; otherwise, the elevator is controlled to execute the third preset door closing emergency plan. 8. The method for elevator safety monitoring according to claim 7, wherein the step of controlling the elevator to execute the preset first door-closing emergency plan/second door-closing emergency plan/third door-closing emergency plan comprises: If it is the first door-closing emergency plan, control the elevator to stop the door-closing action, and output the corresponding voice alarm prompt; If it is the second door-closing emergency plan, control the elevator to slow down the door-closing action, and output the corresponding voice alarm prompt; If it is the third door-closing emergency solution, the door-closing action of the elevator will not be changed, and a corresponding voice alarm prompt will be output. 9. A device for elevator safety monitoring, characterized in that it comprises: The transceiver control module is used to control the preset detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected by the object; The detection depth calculation module is used to calculate the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and obtain the current depth information between the detection device and the object according to the phase difference; A judging module, configured to compare the depth information with a preset safe depth, and judge whether an unsafe behavior occurs in the target monitoring area according to the comparison result; Wherein, the safety depth is: the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area. 10. A system for elevator safety monitoring, comprising an elevator main control, characterized in that it also includes a detection device arranged on the top of the car, and the detection device is connected to the elevator main control; said detection device is capable of emitting and receiving electromagnetic radiation; The main control of the elevator can control the detection device to emit electromagnetic radiation to the target monitoring area of the elevator, and receive the electromagnetic radiation reflected back by the object; calculate the phase difference between the emitted electromagnetic radiation and the received electromagnetic radiation, and according to the phase difference Obtaining the current depth information between the detection device and the object; and comparing the depth information with a preset safety depth, and judging whether an unsafe behavior occurs in the target monitoring area according to the comparison result; Wherein, the safety depth is the minimum depth between the detection device and the target monitoring area when there is no obstacle in the target monitoring area.