Car position detection method for an elevator system

Abstract

The invention discloses a lift car position detection method for an elevator system, and the elevator system comprises a lift car which ascends and descends in a hoistway, a code belt which is arranged along the hoistway, and a reading head which is arranged on the lift car and is used for reading code information on the code belt, the first end of the code belt is fixed to the top end of the shaft, the second end of the code belt is fixed to the bottom end of the shaft through an elastic component, and the change amount of the elongation of the elastic component caused by the acting force between the reading head and the code belt when the elevator car ascends and descends in the shaft is determined and utilized. Correcting a second car position determined according to the encoding information obtained by the reading head to obtain a third car position; and outputting the third car position as an elevator car position. According to the invention, the position detection error caused by the interaction force between the reading head and the code belt can be corrected, and the accuracy of car position detection is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of elevators, and in particular to a method for detecting a car position of an elevator system. Background Art

[0002] At present, many elevators have adopted a car position detection system based on a strip with coded information (such as a code tape), using a sensor (code reading head) installed on the elevator car to detect the coded information on the strip, and then obtain the car position information after processing (mainly the correspondence between the code and the position), such as: Chinese patent document CN2005100914085.

[0003] Considering that the strip-shaped body will change due to thermal expansion and contraction, the elevator car position information obtained by the car position detection system based on the strip-shaped body with coded information (such as a code belt) may have detection errors. In order to solve this problem, Chinese patent documents CN202080106061.X and CN202310076609.6 proposed solutions to the elevator car position detection error caused by temperature changes.

[0004] However, in actual applications, in addition to the elongation of the strip caused by temperature changes (and building settlement) that may cause errors in elevator car position detection, there is another possible reason for errors in elevator car position detection:

[0005] Normally, in order to keep the strip in a vertical state (no shaking or shaking within a limit) and work normally, the upper end of the strip is usually fixed to the top of the shaft, and the lower end is retractably fixed to the bottom of the shaft (such as the lower end of the strip is fixed to the pit floor via a spring, as shown in the figure in Chinese patent document 202080106061.X). For such a scenario, when there is an interaction force between the sensor and the strip, the force from the sensor applied to the strip will cause the elongation of the spring to change. After the elongation of the spring changes, the correspondence between the code and the position originally established based on the absence of such a change also changes. If the correspondence between the code and the position is still used to obtain the car position from the code without correction, the obtained car position will inevitably have a detection error.

[0006] Therefore, when there is an interaction force between the sensor's reading head and the code tape, how to improve the detection accuracy of the car position becomes an unresolved technical problem. Summary of the invention

[0007] The technical problem to be solved by the present invention is how to improve the detection accuracy of the car position when there is an interaction force between the reading head and the code tape.

[0008] In order to solve the above technical problems, the present invention discloses a car position detection method for an elevator system, wherein the elevator system includes a car that is lifted and lowered in a hoistway, a code tape arranged along the hoistway, and a reading head installed on the car for reading the coded information on the code tape, wherein the first end of the code tape is fixed to the top of the hoistway, and the second end is fixed to the bottom of the hoistway via an elastic component. The car position detection method determines and utilizes the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is lifted and lowered in the hoistway, corrects the second car position determined according to the coded information obtained by the reading head, and outputs the corrected third car position as the elevator car position.

[0009] Preferably, the car position detection method determines whether to correct the second car position according to a first direction in which the force acts on the code strip.

[0010] Preferably, when the first direction is the same as the direction of elevator operation, the car position detection method uses the force to correct the second car position only when the elevator car is moving upward; when the force is opposite to the direction of elevator operation, the car position detection method uses the force to correct the second car position only when the elevator car is moving downward.

[0011] Preferably, the car position detection method determines the force between the reading head and the code belt, determines the change in the elongation of the elastic component based on the force, and takes the sum of the second car position and the change in the elongation of the elastic component corresponding to the force as the third car position.

[0012] Preferably, the car position detection method pre-analyzes the generation mechanism of the force between the reading head and the code belt, and determines the magnitude of the force based on the generation mechanism, and when the first direction is the same as the elevator running direction, the change in the elongation of the elastic component at any point during the upward movement of the elevator car is taken as the change in the elongation of the elastic component corresponding to the force; when the first direction is opposite to the elevator running direction, the change in the elongation of the elastic component at any point during the downward movement of the elevator car is taken as the change in the elongation of the elastic component corresponding to the force.

[0013] Preferably, the car position detection method takes the car position when the elevator car passes a specific position in the shaft when the first direction is vertically downward as the first position, takes the car position when the elevator car passes a specific position in the shaft when the first direction is vertically upward as the second position, and takes the difference between the first position and the second position as the change in the elongation of the elastic component.

[0014] Preferably, the elevator system also includes a measuring unit for measuring the elongation of the second end of the code band relative to a reference position, wherein the reference position refers to a reference point when determining the position of an elevator car after the installation and commissioning of the elevator is completed. When determining the position of the elevator car, the car position detection method records a first measurement result of the measuring unit when the elevator car is stationary or when the direction of movement of the elevator car is such that the first direction of the force is vertically downward, and uses the offset of the first measurement result relative to the reference position to correct the first car position to obtain the second car position; the first car position is determined based on the coding information obtained by the reading head.

[0015] Preferably, the car position detection method determines the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is lifted or lowered in the hoistway by: recording the running direction of the elevator car so that the second measurement result of the measuring unit when the first direction is vertically upward; calculating the difference between the second measurement result and the first measurement result, and using the difference as the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is lifted or lowered in the hoistway.

[0016] Preferably, the force comprises at least one of a friction force between the reading head and the code strip, and a force applied by a first one of the reading head and the code strip to a second one through an action of a field generated by the first one of the reading head and the code strip.

[0017] Preferably, when the applied force is the friction force between the reading head and the code strip and the force applied to the second party by the first party of the reading head and the code strip through the action of the field generated by them, the car position detection method determines the applied force according to a pre-established mathematical model that reflects the relationship between the applied force and its influencing factors, and determines the change in the elongation of the elastic component caused by the applied force according to the characteristics of the applied force and the elastic component.

[0018] Preferably, the first party and the second party are configured to keep the direction and magnitude of the force unchanged when the moving direction of the elevator car remains unchanged.

[0019] Beneficial technical effects

[0020] The present invention can correct the position detection error caused by the interaction force between the reading head and the code belt, and improve the accuracy of car position detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of an elevator system that uses code tape and a reader to detect the position of the car. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention. It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence.

[0023] Example 1

[0024] Elevator systems that use code tapes and reading heads to detect the position of the car, such as Figure 1 As shown, the elevator system includes a car that rises and falls in a hoistway, a code tape arranged along the hoistway, and a reading head installed on the car for reading the coded information on the code tape, wherein the first end of the code tape is fixed to the top end of the hoistway, and the second end is fixed to the bottom end of the hoistway via an elastic component.

[0025] The car position detection method for an elevator system provided in this embodiment determines and uses the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is lifted and lowered in the hoistway to correct the second car position determined according to the coded information obtained by the reading head to obtain a third car position; the third car position is output as the elevator car position. In this embodiment, the position information corresponding to the coded information obtained by the reading head is directly determined as the second car position.

[0026] There are many ways to generate the force between the reading head and the code tape. One way of generating the force is, for example, the friction between the reading head and the code tape. This force is directed to a contact-type detection device. The reading head includes a vertical annular body, and the code tape passes through the annular body, thereby limiting the portion of the code tape corresponding to the reading head to a certain range, so that the distance between the code tape and the reading head does not exceed the allowable range, so as to ensure that the reading head can correctly and reliably read the coded information on the code tape. Since there is contact between the code tape and the annular body when the car moves up and down in the hoistway, there is a sliding friction between the two. For the reading head, the direction of the friction force is always opposite to the direction of movement of the car, and for the code tape, the direction of the friction force is always the same as the direction of movement of the car.

[0027] Another form of force is, for example, the force applied to the second party by the first party in the reading head and the code strip through the action of the field generated by them. For example, the force between the reading head and the code strip is generated by the magnetic field. This type of force is related to the magnetic field, the ferromagnetic body (not necessarily limited to ferromagnetic body, as long as it is a material that can be affected by the magnetic field and thus generate force) and the moving speed of the car. According to physical principles, a mathematical model with the magnetic field, the ferromagnetic body (mainly due to its encoding, the characteristics vary with different positions) and the moving speed of the car as independent variables and the force as the dependent variable can be established in advance. The moving speed of the ferromagnetic body and the car can be determined by the detection results of the reading head, and the magnetic field can be determined by the permanent magnet (usually a constant parameter) that generates the magnetic field or the magnetic field generating device of the electric excitation (such as the excitation current).

[0028] When the force is a friction force, the direction of the force acting on the code tape is the same as the direction of movement of the car. When the force is a field force, the direction of the force acting on the code tape may be the same as or opposite to the direction of movement of the car. The direction is determined based on whether the component generating the field is the code tape or the reading head. Therefore, the car position detection method determines whether to correct the second car position according to the first direction of the force acting on the code tape. When the first direction is the same as the direction of elevator operation, the car position detection method only uses the force to correct the second car position when the elevator car is moving upward; when the force is opposite to the direction of elevator operation, the car position detection method only uses the force to correct the second car position when the elevator car is moving downward.

[0029] In general, as long as the force acting on the code belt is downward, since the upper end of the code belt is rigidly fixed to the top of the shaft, the force will not affect the expansion and contraction of the code belt, and there is no need to correct the position of the second car; if the force acting on the code belt is upward, since the lower end of the code belt is fixed to the bottom of the shaft through an elastic component, the force will affect the expansion and contraction of the elastic component, causing the position of the magnetic scale relative to the shaft to change accordingly. If the car position is still obtained based on the code read by the reading head using the pre-established correspondence between the code and the position and used as the actual position of the car, detection errors will inevitably occur. Therefore, it is necessary to correct the car position obtained based on the code read by the reading head using the pre-established correspondence between the code and the position.

[0030] Example 2

[0031] This embodiment specifically describes the method for correcting the car position based on the embodiment 1 as follows:

[0032] The first step is to determine the force between the reading head and the code tape. For example, when the force is the friction between the reading head and the code tape and the force applied to the second party by the first party of the reading head and the code tape through the action of the field generated by them, the car position detection method determines the force based on a pre-established mathematical model that reflects the relationship between the force and its influencing factors.

[0033] In order to ensure the implementation effect, taking the magnetic field as an example, the magnetic field and the ferromagnetic body should ensure that the direction of the force remains unchanged when the direction of movement of the car remains unchanged; that is, the first party (the generated field) and the second party ensure that the direction and magnitude of the force remain unchanged when the direction of movement of the elevator car remains unchanged.

[0034] When the car moves in a given direction at a constant speed, the magnetic field and the ferromagnetic body should be such that the magnitude of the force remains unchanged or increases or decreases monotonically; preferably, the magnetic field is generated by a permanent magnet (so that the magnetic field will be constant), and the linear density of the ferromagnetic body along the length of the magnetic field is constant or increases or decreases monotonically.

[0035] The second step is to determine the change in the elongation of the elastic component according to the action force and the characteristics of the elastic component. When the first direction is the same as the elevator running direction, the change in the elongation of the elastic component at any point during the elevator car's upward movement is taken as the change in the elongation of the elastic component corresponding to the action force; when the first direction is opposite to the elevator running direction, the change in the elongation of the elastic component at any point during the elevator car's downward movement is taken as the change in the elongation of the elastic component corresponding to the action force.

[0036] In the third step, the sum of the second car position and the change in the elongation of the elastic component corresponding to the force is taken as the third car position (i.e., the corrected car position).

[0037] Preferably, the change in the elongation of the elastic component can be measured by the following method: the position of the elevator car when the first direction is vertically downward and the car position when the first direction is vertically upward and the car position when the first direction is vertically upward and the car position when the first direction is vertically upward and the car position when the first direction is vertically upward and the car position when the first direction is vertically upward and the car position when the first direction is vertically upward and the car position when the first direction is vertically upward and the car position when the first direction is vertically upward and the car position when the elongation of the elastic component is determined. The change in the elongation of the elastic component can be obtained by the method without calculating the magnitude of the force, and the direction of the force can be determined, and the change in the elongation of the elastic component can be obtained by actual measurement.

[0038] Example 3

[0039] On the basis of Example 1, this embodiment further considers the detection error of the code band caused by temperature change. At this time, the elevator system also includes a measuring unit for measuring the elongation of the second end of the code band relative to the reference position, and the reference position refers to the reference point when the elevator determines the position of the elevator car after installation and commissioning. When determining the position of the elevator car, the car position detection method records the first measurement result of the measuring unit when the elevator car is stationary or the direction of the elevator car is such that the first direction of the force is vertically downward, and uses the offset of the first measurement result relative to the reference position to correct the first car position to obtain the second car position; the first car position is determined according to the coded information obtained by the reading head.

[0040] Although the second car position is determined based on the coded information obtained by the reading head, the process of determining the second car position in this embodiment is slightly different from that in Embodiment 1. Embodiment 1 directly determines the position information corresponding to the coded information obtained by the reading head as the second car position, while this embodiment first determines the position information corresponding to the coded information obtained by the reading head as the first car position, and then uses the offset of the first measurement result relative to the reference position to correct the first car position to obtain the second car position. In this way, the detection error caused by the temperature change of the code band is corrected.

[0041] The correction method here can utilize the technical solution disclosed in Chinese patent document 202080106061.X, which will not be repeated here.

[0042] After the second car position is obtained, the correction method of embodiment 1 or embodiment 2 can be used to correct the second car position, and finally the third car position is obtained.

[0043] In addition to using the method of Example 2 to determine the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is raised or lowered in the hoistway, this embodiment can also use the following method: record the running direction of the elevator car so that the second measurement result of the measuring unit when the first direction is vertically upward; calculate the difference between the second measurement result and the first measurement result, and use the difference as the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is raised or lowered in the hoistway.

Claims

1. A method for detecting the position of a car in an elevator system, wherein the elevator system comprises a car that is lifted and lowered in a hoistway, a code tape arranged along the hoistway, and a reading head installed on the car for reading the coded information on the code tape, wherein the first end of the code tape is fixed to the top of the hoistway, and the second end is fixed to the bottom of the hoistway via an elastic component, wherein: The car position detection method determines and utilizes the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is raised and lowered in the hoistway, corrects the second car position determined according to the coding information obtained by the reading head, and obtains the third car position; the third car position is output as the elevator car position.

2. The method for detecting the car position of an elevator system according to claim 1, characterized in that: The car position detection method determines whether to correct the second car position according to a first direction in which the force acts on the code strip.

3. The method for detecting the car position of an elevator system according to claim 2, characterized in that: When the first direction is the same as the direction of elevator operation, the car position detection method uses the force to correct the second car position only when the elevator car is moving upward; when the force is opposite to the direction of elevator operation, the car position detection method uses the force to correct the second car position only when the elevator car is moving downward.

4. The method for detecting the car position of an elevator system according to claim 3, characterized in that: The car position detection method determines the force between the reading head and the code belt, determines the change in the elongation of the elastic component according to the force, and takes the sum of the second car position and the change in the elongation of the elastic component corresponding to the force as the third car position.

5. The method for detecting the car position of an elevator system according to claim 4, characterized in that: The car position detection method pre-analyzes the generation mechanism of the force between the reading head and the code tape, and determines the magnitude of the force according to the generation mechanism, and when the first direction is the same as the elevator running direction, the change in the elongation of the elastic component at any point during the upward movement of the elevator car is used as the change in the elongation of the elastic component corresponding to the force; When the first direction is opposite to the elevator running direction, the change in the elongation of the elastic component at any point during the downward movement of the elevator car is taken as the change in the elongation of the elastic component corresponding to the acting force.

6. The method for detecting the car position of an elevator system according to claim 5, characterized in that: The car position detection method uses the car position when the first direction is vertically downward and passes through a specific position in the shaft as the first position, uses the car position when the first direction is vertically upward and passes through the specific position in the shaft as the second position, and uses the difference between the first position and the second position as the change in the elongation of the elastic component.

7. The method for detecting the car position of an elevator system according to claim 1, characterized in that: The elevator system also includes a measuring unit for measuring the elongation of the second end of the code band relative to a reference position, wherein the reference position refers to a reference point when the elevator car position is determined after the installation and commissioning is completed. When determining the elevator car position, the car position detection method records a first measurement result of the measuring unit when the elevator car is stationary or the elevator car is running in a direction such that the first direction of the force is vertically downward, and uses the offset of the first measurement result relative to the reference position to correct the first car position to obtain the second car position; the first car position is determined based on the coding information obtained by the reading head.

8. The method for detecting the car position of an elevator system according to claim 7, characterized in that: The method for determining the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car is lifted or lowered in the hoistway is as follows: Recording the running direction of the elevator car so that the second measurement result of the measuring unit when the first direction is vertically upward; The difference between the second measurement result and the first measurement result is calculated, and the difference is used as the change in the elongation of the elastic component caused by the force between the reading head and the code tape when the elevator car rises and falls in the hoistway.

9. The method for detecting the car position of an elevator system according to any one of claims 1 to 8, characterized in that: The acting force comprises at least one of a friction force between the reading head and the code strip, and a force applied by a first one of the reading head and the code strip to a second one through an action of a field generated by the first one of the reading head and the code strip.

10. The method for detecting the car position of an elevator system according to claim 9, characterized in that: When the applied force is the friction force between the reading head and the code tape and the force applied to the second party by the first party of the reading head and the code tape through the action of the field generated by them, the car position detection method determines the applied force based on a pre-established mathematical model that reflects the relationship between the applied force and its influencing factors, and determines the change in the elongation of the elastic component caused by the applied force based on the characteristics of the applied force and the elastic component.

11. The method for detecting the car position of an elevator system according to claim 10, characterized in that: The first party and the second party ensure that the direction and magnitude of the force remain unchanged when the moving direction of the elevator car remains unchanged.

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