Terminal protection system and method based on absolute position of lift car

Abstract

The invention discloses a terminal protection system based on the absolute position of a lift car. The terminal protection system comprises a learning module, a storage module, an elevator lift car running position real-time monitoring module, a comparative analysis and judgment module, a signal output module, a control execution module and an absolute position value validity detection module. Whether the lift car is located at the abnormal position or not is judged through the lift car absolute position value, whether the lift car absolute position value obtained by the control system accurately reflects the actual position of the lift car or not is effectively judged through a certain mechanism, and the effectiveness of terminal protection is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of elevators, and particularly to a terminal protection system and method based on the absolute position of a car. Background Art

[0002] In order to ensure that the car can be effectively braked before running abnormally to the terminal of the hoistway and avoid casualties caused by the car hitting the top or bottom of the hoistway, terminal switches are generally installed near the terminal of the hoistway. The installation position of the terminal switch is outside the normal operation range and within the hoistway terminal range. When the car passes the switch (overshooting operation), the car is already in an abnormal position. At this time, the control system cuts off the power supply of the traction device and makes the brake apply braking to forcefully brake the car. Finally, with the assistance of devices such as buffers, the car is safely stopped in front of the hoistway terminal. The schematic diagram of the hoistway terminal protection mechanism using the hoistway terminal switch is as Figure 1 shown. In the figure, when the car (A) is in a position exceeding the upper terminal landing area (D), the terminal switch detection device (B) installed on the car causes the terminal switch (C) installed near the hoistway terminal to send an action signal. After receiving the signal, the control system brakes the car emergently, and finally the car stops in front of the terminal (position A').

[0003] The hoistway terminal switch is generally an electrical device including a mechanical structure. As the elevator is used, the internal and external components of the switch gradually age, and the terminal switch may have problems such as failure to act or delayed action. Even with the existing non-contact electrical detection methods such as optical detection in the prior art, since the terminal switch is installed in a position that the elevator does not pass through during normal operation, it is still difficult to verify whether the switch is effective during normal elevator operation. On the other hand, mechanical vibrations and electromagnetic interference generated during elevator operation may also cause the switch to malfunction, resulting in abnormal braking of the elevator and affecting the comfortable use of passengers.

[0004] Therefore, how to avoid the disadvantages of the hoistway switch and perform terminal protection of the car based on other more stable and reliable means that can also judge the effectiveness during normal elevator operation is a problem to be solved.

[0005] On the other hand, by adding a position sensor to the car and cooperating with arranging position markers (scales) penetrating the hoistway in the hoistway, continuous detection of the absolute position of the car relative to the bottom end of the hoistway can be achieved. Therefore, it is also possible to judge whether the position of the car is abnormal (close to the hoistway terminal) through the real-time absolute position value of the car, and then perform terminal protection of the car. Compared with the hoistway terminal switch, through absolute position detection, it is possible to avoid the protection mechanism not acting when the car passes near the hoistway terminal due to switch abnormalities; or abnormal emergency stops caused by switch malfunctions during normal elevator operation. The schematic diagram of the hoistway terminal protection mechanism using the car absolute position detection system is as Figure 2As shown in the figure. In the figure, when the car (A) is in a position exceeding the upper terminal landing door zone (D), the absolute position sensor (B) installed on the car reads the absolute position information on the scale installed in the hoistway and transmits the absolute position value of the car to the control system. The control system determines that the current position of the car has exceeded the normal operating range and is within the range of the position to be protected, then brakes the car emergently, and finally makes the car stop in front of the terminal (position A').

[0006] The terminal protection mechanism based on the absolute position of the car completely depends on the absolute position detection value of the car, and requires the control system to be able to know the accurate actual position of the car in the hoistway through the absolute position detection value. Before the elevator is put into use, through certain operation steps, the elevator control system needs to learn the relationship between the actual position of the car and the absolute position detection value, such as the position value of the lowest point of the hoistway, the position value of the highest point, etc.

[0007] After the elevator is put into use, the sensor or the scale may move for some reasons, which may cause the absolute position detection value not to match the actual position of the car anymore. If the deviation is large, when the car runs to an abnormal position, the control system may still think that the car is within the safe operating range, resulting in the failure of the hoistway terminal protection mechanism based on the absolute position and causing safety risks to the elevator. As Figure 3 shown in the figure, if the installation position of the sensor is moved downward, the actual position of the car will be higher than the absolute position value of the car detected by the control system, and there is a risk of terminal protection failure. Although the existing technology uses the method of segmented marking on the scale to let the elevator system determine the terminal position, it not only requires installing multiple special sensors, increasing the cost, but also cannot avoid the risk of terminal protection failure caused by the overall displacement of the scale.

[0008] Therefore, if the scale is replaced or the scale and the sensor are moved and no calibration operation is performed, the absolute position detection value will no longer match the actual position of the car. In this case, how to judge the abnormality of the position detection value in time through certain mechanisms and stop the elevator in advance to prevent it from approaching the terminal is also a technical problem to be solved.

[0009] In addition, for elevators using an absolute position detection system, since the scale is a slender object with a length approximately the same as that of the hoistway, it is difficult to avoid deformation caused by factors such as the elongation of the material itself, thermal expansion and contraction, and the change of the tension of the tensioning components due to aging. This results in that when the car is in the same position, the absolute position detection value obtained by the control system will also change within a certain range.

[0010] For some elevators (such as those with shallow pits and low top floors), when the car stops normally at the terminal floor, the distance (overspeed) between the bottom of the car / counterweight and the upper end face of the buffer is very limited. This poses a requirement for the control system to accurately identify that the car has jumped out of the terminal floor leveling area and entered the terminal abnormal area and to take protection measures in a timely manner. For the shaft terminal protection mechanism based on absolute position, the change in the absolute position detection value caused by the deformation of the scale may lead to the inability of the control system to effectively and timely provide terminal protection in this situation. As Figure 4 shown, when the scale (C) elongates due to a temperature rise (shown in red), the lower terminal protection action point (E) moves downward accordingly. If the protection area is small, there is a risk of protection failure (the power system is still running when the car hits the buffer (F)).

[0011] How to effectively identify and compensate for the inaccuracy of the absolute position of the scale caused by itself and the environment through a certain mechanism, ensure that the absolute position detection value accurately reflects the actual position of the car, and further ensure that the shaft terminal protection mechanism can also provide effective protection when the protection area is short is a technical problem to be solved. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide a terminal protection system based on the absolute position of the car, which determines whether the car is in an abnormal position through the absolute position value of the car, effectively determines whether the absolute position value of the car obtained by the control system accurately reflects the actual position of the car through a certain mechanism, ensures the effectiveness of terminal protection, and compensates for the inaccuracy of the absolute position of the scale caused by itself and the environment through a compensation mechanism, further ensuring that the terminal protection mechanism can also provide effective protection when the protection area is short.

[0013] To solve the above technical problems, the present invention discloses a terminal protection system based on the absolute position of the car, including:

[0014] Learning module: learning the absolute position of the normal operating range of the elevator car;

[0015] Storage module: storing and memorizing the absolute position value of the normal operating range of the elevator car learned by the learning module;

[0016] Real-time monitoring module for the running position of the elevator car: used for real-time monitoring of the running position of the elevator car to obtain the absolute position value of the elevator car;

[0017] Comparison, analysis and judgment module: comparing the absolute position value of the elevator car with the absolute position value of the normal operating range of the elevator car stored, and judging and analyzing whether the elevator car exceeds the normal operating range;

[0018] Signal output module: outputting a signal at the moment when the comparison, analysis and judgment module determines that the elevator car is exceeding the normal operating range;

[0019] The control execution module: receives the signal from the signal output module, issues an instruction to stop the elevator operation, and stops the elevator from ascending and descending.

[0020] Preferably, the real-time monitoring module for the running position of the elevator car includes an absolute position validity detection switch device, and when the car runs near the terminal of the hoistway, the absolute position validity detection switch device will be actuated.

[0021] Preferably, the absolute position validity detection switch device is an absolute position validity detection switch device capable of compensating for the deformation of the scale, and the method for detecting and compensating the scale deformation is as follows:

[0022] Each time the car passes the lower absolute position validity detection switch, calculate the difference between the actual detection switch actuation point position value and the learned detection switch position value, and obtain the current hoistway terminal protection actuation point position through the following formula:

[0023] e 下检测开关 = X 实际下开关动作位置 - X 下开关动作学习位置

[0024]

[0025] In the formula, X 井道上端 is approximately selected as the learning point of the upper protection switch actuation or the upper terminal floor leveling position point.

[0026] Preferably, the scale deformation compensation mechanism is used for leveling point compensation, and the method is as follows:

[0027]

[0028] Preferably, the absolute position validity detection switch device includes an optoelectronic switch and a light-shielding plate.

[0029] Preferably, the absolute position validity detection switch device includes a ball switch and a striking bow.

[0030] The present invention discloses a terminal protection method for an elevator based on absolute position, including the following steps:

[0031] Step S101: Learn the absolute position within the normal running range of the elevator car;

[0032] Step S102: Store the absolute position value within the normal running range of the elevator car learned in step S101;

[0033] Step S103: Real-time monitor the running position of the elevator car to obtain the value of the elevator car approaching the terminal position;

[0034] Step S104: Compare the elevator car approaching the terminal position value in step S103 with the absolute position value of the normal operating range of the elevator car stored in step S102;

[0035] Step S105: Determine whether the elevator car exceeds the normal operating range;

[0036] Step S106: When the comparison and judgment in step S105 identify that the elevator car is instantaneously exceeding the normal operating range, send a signal to the control system;

[0037] Step S107: When the control system receives the signal, immediately issue an instruction to stop the elevator operation and stop the elevator from ascending and descending.

[0038] Preferably, in step S101, the absolute position learning of the normal operating range of the elevator car is the learning of the absolute position value when the absolute position validity detection switch acts.

[0039] Preferably, after step S101, it further includes:

[0040] Step S201: Real-time detect whether the elevator car is approaching the terminal floor.

[0041] Preferably, if the elevator car is close to the terminal floor, after step S201, it further includes:

[0042] Step S202: Determine whether the detection switch acts. If the detection switch acts, then determine whether the deviation between the absolute position at the time of switch action and the learned record value is within a reasonable range. If it is not within a reasonable range, send a signal to the control system to stop the elevator.

[0043] Preferably, if the elevator car is close to the terminal floor, after step S201, it further includes:

[0044] Step S203: Determine whether the detection switch acts. If the detection switch does not act, then determine whether the absolute position of the car exceeds the reasonable range of detection switch action. If it exceeds the reasonable range, send a signal to the control system to stop the elevator.

[0045] Preferably, if the elevator is not close to the terminal floor, after step S201, it further includes:

[0046] Step S204: Determine whether the absolute position of the car exceeds the reasonable range of detection switch action. If it exceeds the reasonable range, send a signal to the control system to stop the elevator.

[0047] The present invention has the following technical effects:

[0048] 1. By judging whether the car exceeds the normal operating range through the absolute position, this judgment switch is saved

[0049] 2. By reusing the switches that can operate within the normal operating range, it is determined whether the collected absolute position is valid, thereby ensuring the normal function of Objective 1.

[0050] 3. Since the validity judgment can be made within the normal operating range of the elevator, it is possible to avoid the risk that the car runs to the terminal, but the terminal switch fails and the car exceeds the normal operation and cannot be detected for protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0052] Figure 1 FIG. is a schematic diagram of a terminal protection mechanism based on shaft terminal switches in the prior art.

[0053] Figure 2 FIG. is a schematic diagram of a terminal protection mechanism based on the absolute position of the car in the prior art.

[0054] Figure 3 FIG. is a schematic diagram of the failure of the shaft terminal protection device due to the displacement of the sensor installation in the prior art.

[0055] Figure 4 FIG. is a schematic diagram of the downward movement of the terminal protection action point due to the elongation of the scale in the prior art.

[0056] Figure 5 FIG. is a flowchart of a preferred embodiment of the elevator car absolute position detection method of the present invention.

[0057] Figure 6 FIG. is a flowchart of another preferred embodiment of the elevator car absolute position detection method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] The following specific embodiments are used to illustrate the implementation manners 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 implementation manners. The details in this specification can also be applied based on different viewpoints, and various modifications or changes can be made without departing from the overall design concept of the invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments 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 only to the specific embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present invention complete and thorough, and to fully convey the technical solutions of these exemplary specific embodiments to those skilled in the art.

[0059] Embodiment 1

[0060] The flow chart of the shaft terminal protection mechanism based on the absolute position of the car is as follows: Figure 5 shown.

[0061] For elevators equipped with a car absolute position detection system, the car absolute position can be used to determine whether the car is near the end of the shaft. If so, the elevator needs to be stopped immediately to prevent the car from rushing to the top or squatting at the bottom, causing personal injury or death to passengers. The premise for the normal implementation of this function is that the control system can infer the actual position of the car in the shaft through the obtained car absolute position value, and then determine whether protection is needed.

[0062] Therefore, before the elevator is put into normal operation, it is necessary to manually operate the elevator control system to learn the relationship between the absolute position value of the car and the actual position of the car. The learning content mainly includes: the absolute position of the car when it stops at each stop floor, the absolute position of the car when it is running near the shaft terminal, etc.

[0063] When the control system has learned the absolute position value corresponding to the normal operating range of the well, the well terminal protection mechanism takes effect. The control system obtains the absolute position of the car in real time during operation. When the control system determines that the car is close to the well terminal through the absolute position of the car and reaches or exceeds the terminal protection position point, the control system activates the terminal protection mechanism, cuts off the power supply of the traction system, and applies forced braking of the brake, etc. This forces the car to be braked to prevent the car from hitting the well terminal.

[0064] Example 2

[0065] The premise for the normal implementation of the hoistway terminal protection mechanism based on the absolute position of the car is that the absolute position value of the car obtained by the control system corresponds correctly to the actual position of the car in the hoistway. Therefore, it is necessary to let the control system learn the relationship between the absolute position value of the car and the actual position of the car through manual operation.

[0066] However, with the use of the elevator or subsequent maintenance work, the relationship between the absolute position value of the car and the actual position of the car may deviate due to some reasons: such as: the scale installation part sinks relative to the shaft, the scale is moved or replaced manually, the sensor installed in the car is moved manually in the vertical direction, etc. When the absolute position value cannot accurately reflect the actual position of the car in the shaft, the absolute position detection is invalid, and the shaft terminal protection mechanism based on the absolute position of the car may fail: when the control system determines that the car is still in a safe position based on the absolute position of the car, the actual car may have reached the shaft terminal.

[0067] The present invention employs a set of detection switches (such as photoelectric switches, light-shielding plates, ball switches, and striking bows, which are respectively installed near the car and the well shaft terminals), hereinafter referred to as absolute position validity detection switches. When the car runs near the well shaft terminals (within the normal operating range), the absolute position validity detection switches will be actuated. For example, a photoelectric switch is installed on the car, and light-shielding plates are installed near the upper and lower terminal floors of the well shaft. It is ensured that before the car reaches the upper or lower terminal floor, the light-shielding plate will pass by the photoelectric switch to make the absolute position validity detection switch emit an actuation signal. After the control system receives the actuation signal, it compares the real-time value of the absolute position of the car with the recorded value of the absolute position of the car at the switch actuation point during learning. If the deviation between the real-time position value and the comparison value exceeds the threshold, the control system determines that the car position value provided by the car absolute position detection system can no longer reflect the actual position of the car, and the absolute position detection function fails, thus unable to ensure that the terminal protection mechanism based on the absolute position of the car can be effectively executed. At this time, the control system will forcibly stop the car to prevent the car from approaching the well shaft terminal further.

[0068] Although the absolute position well shaft terminal protection mechanism including the absolute position validity detection switch and the well shaft terminal protection mechanism based on terminal switches both include switch components, the installation positions, functions, and underlying principles of the switches are completely different. Comparatively, it has the following advantages:

[0069] 1. The absolute position validity detection switches are arranged within the normal operating range of the car. Therefore, the functionality of the switches can be confirmed every time the car runs to the terminal floor, thus ensuring the effectiveness of the absolute position and terminal protection functions and avoiding the risk that the car runs near the terminal but the terminal switch fails to provide protection.

[0070] 2. The absolute position validity detection switches are arranged within the normal operating range of the car, with a flexible arrangement position. They can be shared with other function detection switches, reducing costs.

[0071] 3. Under the well shaft terminal protection mechanism based on terminal switches, the action point of the protection mechanism is the position point where the car actuates the terminal switch. When it needs to be changed, the installation position of the switch needs to be adjusted manually, which is time-consuming and laborious. Under the well shaft terminal protection mechanism based on absolute position, the action point of the protection mechanism is the position recorded when the car travels to the action point during the learning operation. Comparatively, it is easier to adjust the action point. One only needs to enter the learning operation and drive the car in the maintenance mode.

[0072] The detection flow chart for ensuring the effective execution of the well shaft terminal protection mechanism by judging whether the absolute position value of the car corresponds to the actual position of the car through the absolute position validity detection switch is as Figure 6 shown.

[0073] Embodiment 3

[0074] On the other hand, for some elevators, the leveling position of the terminal floor is relatively close to the upper end face of the buffer (overtravel) (such as in shallow pits and low top floors). This results in a very small margin for the range of the terminal protection action point of such elevators (the terminal protection action point should be outside the leveling position (including the re-leveling area) and before the car / counterweight contacts the upper end face of the buffer). Therefore, this poses a requirement for the control system to accurately determine whether the car is located at the protection action point.

[0075] The absolute position detection system includes sensors on the car side and scale components on the hoistway side. The scale is generally a slender object with a length close to that of the hoistway, which is suspended or attached. It will inevitably be affected by factors such as material stretching, thermal expansion and contraction, changes in the tension of the tensioning device, and changes in the adhesion of the attachment, resulting in deformation. The absolute position value recorded on the scale will also produce a slight offset in the vertical direction along with the deformation of the scale.

[0076] The deformation of the scale can reach the centimeter level, that is, when the car reads the same absolute position value in the lower section of the hoistway, the actual position of the car may deviate by several centimeters. For elevators with a small overtravel, the distance from the protection action point to the upper end face of the buffer may also be only a few centimeters. If no compensation measures are taken for the deviation of the scale deformation, it may occur that when the car hits the upper end face of the buffer, the control system has not detected the abnormal position of the car and the power system has not been powered off, posing a safety risk.

[0077] The detection switch device proposed in Embodiment 2 can be used to compensate for the deformation of the scale. The method for detecting and compensating the scale deformation is as follows: Each time the car passes the lower absolute position validity detection switch, calculate the difference between the actual detection switch action point position value and the learned detection switch position value. Assuming that the deformation of the scale is uniform and linear, the position of the current hoistway terminal protection action point can be obtained through the following formula:

[0078] e 下检测开关 = X 实际下开关动作位置 - X 下开关动作学习位置

[0079]

[0080] In the formula, X 井道上端 can be approximately selected as the learning point of the upper protection switch action or the upper terminal floor leveling position point.

[0081] Furthermore, this scale deformation compensation mechanism can also be used for leveling point compensation to improve the leveling accuracy:

[0082]

[0083] Based on the car absolute position detection system, the present invention judges whether the car is close to the vicinity of the hoistway terminal by detecting the car absolute position in real time and comparing it with the pre-learned hoistway absolute position range. If the car position passes through the position point to be protected (abnormal position), the control system forcibly stops the car by cutting off the power supply of the traction machine, emergency braking of the brake, etc., to prevent the car from hitting the hoistway terminal.

[0084] Meanwhile, the present invention is equipped with a set of detection switches (such as photoelectric switches and light-shielding plates, ball switches and striking bows, etc., which are respectively installed near the car and the hoistway terminal). When the car runs near the terminal floor, the switches are actuated. At this time, the control system compares the detected value of the car absolute position when the switches are actuated with the pre-learned switch position value. If the deviation exceeds the threshold value, the control system determines that the currently detected value of the car absolute position is not credible (absolute position detection fails), and the effectiveness of the hoistway terminal protection mechanism cannot be guaranteed. The control system will detect the fault, forcibly stop the elevator, and prevent the car from approaching the hoistway terminal further.

[0085] In addition, in the present invention, when the absolute position validity detection switch is actuated when the car runs near the terminal floor, the control system first performs the function of judging the absolute position by the above-mentioned detection switches. If it is judged that the absolute position detection is credible, the difference between the currently detected value of the switch position and the learned value of the switch position is calculated. According to the positional relationship between the learned value of the switch position and the learned value of the protection position point, the actual absolute position value of the current protection position point is calculated and converted as the current terminal protection action point, further improving the accuracy of protection. In addition, the flat layer positions can also be compensated by converting the position difference of the switches to improve the flat layer accuracy.

[0086] The present invention has been described in detail through specific embodiments and examples above, but these do not constitute a limitation to the present invention. Without departing from the principle of the present invention, those skilled in the art can also make many modifications and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. A terminal protection system based on the absolute position of the car, characterized in that: include: Learning module: to learn the absolute position of the elevator car within the normal operating range; Storage module: stores and memorizes the absolute position value of the normal operating range of the elevator car after learning by the learning module; Elevator car running position real-time monitoring module: used for real-time monitoring of the elevator car running position and obtaining the real-time absolute position value of the elevator car; Comparison analysis and judgment module: compares the real-time absolute position value of the elevator car with the stored absolute position value of the normal operating range of the elevator car, and judges and analyzes whether the elevator car exceeds the normal operating range; Signal output module: outputs a signal when the elevator car is out of the normal operating range according to the comparison and analysis module; Control execution module: receives the signal from the signal output module, issues a command to stop the elevator operation, and stops the elevator from rising or falling; The absolute position value validity detection module can determine whether the absolute position value of the car can reflect the actual position of the car through comparison.

2. The terminal protection system based on the absolute position of the car according to claim 1 is characterized in that ,The absolute position value validity detection module includes an absolute position validity detection switch. When the car runs to the vicinity of the well terminal, the absolute position validity detection switch will be actuated.

3. The terminal protection system based on the absolute position of the car according to claim 2, characterized in that: The absolute position validity detection switch device has the function of detecting and compensating for scale deformation, and the scale deformation detection and compensation method is as follows: Each time the car passes the absolute position validity detection switch, the difference between the actual detection switch action point position value and the learning detection switch position value is calculated, and the current well terminal protection action point position is obtained by the following formula: e 下检测开关 =X 实际下开关动作位置 -X 下开关动作学习位置 Where, X 井道上端 The approximate selection is the upper protection switch action learning point or the upper terminal layer leveling position point.

4. The terminal protection system based on the absolute position of the car according to claim 3 is characterized in that: The scale deformation compensation mechanism is used for leveling point compensation, and the method is as follows:

5. A terminal protection method based on the absolute position of the car, characterized in that: The following steps are involved: Step S101, learning the absolute position of the elevator car in the normal operating range; Step S102, storing the absolute position value of the normal operating range of the elevator car after learning in step S101; Step S103: monitor the running position of the elevator car in real time and obtain the absolute position value of the elevator car; Step S104: Compare the elevator car terminal approach position value in step S103 with the elevator car normal operation range absolute position value stored in step S102; Step S105: Determine whether the elevator car is beyond the normal operating range; Step S106: The comparison and judgment in step S105 identifies that the elevator car is exceeding the normal operating range and sends a signal to the control system; Step S107: The control system immediately issues a command to stop the elevator operation upon receiving the signal, thereby stopping the elevator from rising or falling.

6. The method for detecting the absolute position of an elevator car according to claim 5, characterized in that: In the step S101, the elevator car is subjected to absolute position learning within the normal operating range and the terminal accessory detection switch is subjected to absolute position learning when the terminal accessory detection switch is actuated.

7. The terminal protection method based on the absolute position of the car according to claim 5, characterized in that: After step S101, the method further includes: Step S201, real-time detection of whether the elevator car is approaching the terminal floor.

8. The terminal protection method based on the absolute position of the car according to claim 7, characterized in that: If the elevator car is close to the terminal floor, the following steps are further included after step S201: Step S202, determine whether the detection switch is actuated. If the detection switch is actuated, determine whether the deviation between the absolute position and the learning record value when the switch is actuated is within a reasonable range. If it is not within a reasonable range, the absolute position is considered invalid and a signal is sent to stop the elevator.

9. The terminal protection method based on the absolute position of the car according to claim 7, characterized in that: If the elevator car is close to the terminal floor, the following steps are further included after step S201: Step S203, determine whether the detection switch is actuated. If the detection switch is not actuated, determine whether the absolute position of the car exceeds the reasonable range of the detection switch actuation. If it exceeds the reasonable range, send a signal to the control system to stop the elevator.

10. The terminal protection method based on the absolute position of the car according to claim 7, characterized in that: If the elevator is not close to the terminal floor, the following steps are further included after step S201: Step S204, determine whether the absolute position of the car exceeds the reasonable range of the detection switch action. If it exceeds the reasonable range, send a signal to the control system to stop the elevator.

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