Electromagnetic brake air gap distance detection method

Abstract

This invention provides a method for detecting the air gap distance of an electromagnetic brake, solving the problems of low efficiency and high difficulty in manual detection of air gap distance in existing electromagnetic brake processes. The method includes the following steps: collecting data; setting several calibration positions between the electromagnetic brake armature and the stationary plate; fixing the electromagnetic brake armature according to the calibration positions to form an air gap position corresponding to each calibration position; energizing the brake coil; and sequentially recording the coil voltage for each calibration air gap. u and coil current i The flux linkage curve for each air gap is calculated using the flux linkage calculation formula, and a discrete flux linkage-current meter is established. The air gap at the detection point is calculated using the data from the four nearest points and the upper and lower limit air gaps. This allows for real-time comparison between the preset brake gap value stored in the status monitoring device and the current automatically detected air gap value, thereby determining the brake's wear condition and achieving real-time early warning, minimizing equipment accidents.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic brake testing technology, and in particular to a method for detecting the air gap distance of an electromagnetic brake. Background Technology

[0002] Electromagnetic brakes are crucial safety protection devices in lifting equipment such as elevators, directly impacting their safe operation. An electromagnetic brake consists of an armature, a stationary plate, and a coil. Electromagnetic brakes without monitoring and early warning devices are connected to the host computer control system via coil wiring. The distance between the armature's working surface and the stationary plate's working surface, defined as the armature's stroke, is called the air gap. When the coil is energized, the armature is attracted to the stationary plate by electromagnetic force, resulting in a zero air gap. When the coil is de-energized, the armature is reset by spring force, releasing the brake, which is when the air gap is at its maximum. The size of the air gap is the most important parameter for the electromagnetic brake's operating status. To ensure the safe operation of lifting equipment like elevators, frequent monitoring of the air gap is necessary. Currently, a common monitoring method involves installing microswitches at the armature's position. However, this only monitors the armature's movement and cannot provide quantitative monitoring of the air gap position or operating distance. Furthermore, due to the small armature stroke (generally no more than 0.5 mm, or even less), the microswitches cannot operate reliably, resulting in low reliability for monitoring devices using microswitches. Changes in the air gap size of an electromagnetic brake directly reflect the wear condition of the brake. If the gap is too large and the wear is severe, the elevator may become uncontrollable and cause a hazard. Current detection methods mandate manual inspection of the brake's wear every 15 days, requiring immediate replacement if wear is severe. However, this method is inefficient and difficult. In patent document CN113865476A, the applicant discloses a real-time status monitoring and early warning method and device for electromagnetic brakes. This invention utilizes this real-time status monitoring device to employ a method for detecting the air gap distance of an electromagnetic brake. Summary of the Invention

[0003] The purpose of this invention is to provide a method for detecting the air gap distance of an electromagnetic brake, which solves the problems of low efficiency and high difficulty in manual detection of the air gap distance in existing electromagnetic brake processes. It achieves automatic detection and early warning of the brake gap by establishing a magnetic flux table for the electromagnetic brake and performing table lookup calculations.

[0004] The technical solution adopted in this invention is: a method for detecting the air gap distance of an electromagnetic brake, comprising the following steps:

[0005] Step 1: Data Collection

[0006] Several calibration positions x1, x2, ..., x are set between the armature and the stationary plate of the electromagnetic brake. nFix the armature of the electromagnetic brake at the calibrated position to form an air gap position corresponding to each calibrated position. Energize the brake coil and record the coil voltage u and coil current i for each calibrated air gap in sequence.

[0007] Step 2: Calculate the flux linkage curve for each air gap using the flux linkage calculation formula.

[0008] The flux linkage is calculated using the following formula for the coil voltage u and coil current i recorded for each air gap.

[0009]

[0010] Where R is the brake coil resistance and t is the sampling time;

[0011] Step 3: Establish a discrete flux linkage-ammeter

[0012] (1) Set several discrete current points i at equal intervals for the brake current. k ={i1, i2, ..., i m};

[0013] (2) According to the air gap sequence, the above discrete currents i are connected one by one. k Corresponding magnetic flux The values ​​are marked in the discrete flux-current table;

[0014] Step 4: Determine the location of the point to be detected in the discrete flux linkage-current meter.

[0015] (1) The coil of the brake to be tested is energized and the coil voltage u and coil current i are recorded;

[0016] (2) Specify the specific current point i of the brake to be tested p Find out i p The time t of point ip And calculate its corresponding magnetic flux linkage Ψ p :

[0017]

[0018] (3) Search p(i) p ,Ψ p The position of point p(i) in the discrete flux linkage-current meter determines the area surrounding p(i). p ,Ψ p Data for the four neighboring points of point Ψ: a(i1,Ψ) a ),b(i2,Ψ b ),c(i1,Ψ c ),d(i2,Ψ d )

[0019] (4) Determine the lower limit air gap x1 from points a and b, and determine the upper limit air gap x2 from points c and d;

[0020] Step 5: Calculate the air gap at the detection point based on the data from the four nearest points and the upper and lower limit air gaps.

[0021] use Formula (1) calculates the ratio t of point p on line segment ab. i ;

[0022] Using ψ e =(1-t) i )ψ a +t i ψ b Formula (2) according to the ratio t i Calculate the magnetic flux interpolation data Ψ of point p on line segment ab. e ;

[0023] Using ψ f =(1-t) i )ψ c +t i ψ d Formula (3) based on the ratio t i Calculate the magnetic flux interpolation data Ψ of point p on line segment cd. f ;

[0024] use Formula (4) calculates the ratio t of point p on line segment ef. Ψ ;

[0025] Using x p =(1-t) ψ )x1+t ψ x2 according to the ratio t Ψ Calculate the interpolation data x of the air gap at the detection point between the lower limit air gap x1 and the upper limit air gap x2. p .

[0026] The advantages and positive effects of this invention are as follows: This invention utilizes the detection data of the voltage and current of the electromagnetic brake to calculate the brake's flux linkage data and constructs a discrete flux linkage-current meter. During each brake operation, the real-time brake status monitoring device calculates the current flux linkage data of the brake and obtains the current brake gap value through interpolation calculations in the discrete flux linkage-current meter, thereby achieving automatic detection of the brake gap and improving detection efficiency. By comparing the preset brake gap value stored in the real-time status monitoring device with the automatically detected current air gap value, the wear condition of the brake can be determined, achieving real-time early warning and minimizing equipment accidents. Attached Figure Description

[0027] The present invention will be further described in detail below with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the electrical principle of the electromagnetic brake real-time status monitoring device used in this invention;

[0029] Figure 2 This is a schematic diagram of the electromagnetic brake structure.

[0030] Figure 3 This is a schematic diagram of the discrete flux linkage-ammeter of the present invention;

[0031] Figure 4 This is a schematic diagram showing the location of the air gap point to be measured in the discrete flux-current meter according to the present invention;

[0032] Figure 5 yes Figure 4 Enlarged view of the location of the air gap point to be tested;

[0033] Figure 6 This is a schematic diagram of a discrete flux linkage-ammeter according to an embodiment of the present invention;

[0034] Figure 7 yes Figure 6 A schematic diagram showing the location of the air gap point to be measured in the discrete flux-current meter;

[0035] Figure 8 yes Figure 7 Enlarged view of the location of the air gap point to be tested.

[0036] The numbers in the diagram are explained as follows: 1. Host computer control system; 2. Coil circuit; 3. Monitoring and early warning circuit; 4. Monitoring and early warning device; 5. Voltage sampling module; 6. Current sampling module; 7. MCU component; 8. Monitoring and early warning output module; 9. Electromagnetic brake; 10. Armature; 11. Armature working surface; 12. Air gap; 13. Stationary plate working surface; 14. Coil; 15. Stationary plate. Detailed Implementation

[0037] according to Figure 1-8 This invention details a method for detecting the air gap distance of an electromagnetic brake. This method utilizes a real-time status monitoring and early warning device for electromagnetic brakes, as described in the applicant's patent document CN113865476A. The real-time status monitoring and early warning device is implemented for example... Figure 1 and Figure 2As shown, a monitoring and early warning device is installed on the coil line between the electromagnetic brake and the host computer control system to collect the current i and voltage U signals of the coil line. The calculated dynamic air gap value is then returned to the host computer control system via the monitoring and early warning line. The monitoring and early warning device connects the host computer control system and the brake coil line. It includes a current sampling module AMC1200, a voltage sampling module AMC1200, a single-chip microcomputer (MCU) component STM32F103, and a monitoring and early warning output module TJA1050. The current sampling module is connected in series in the coil line, and the voltage sampling module is connected in parallel in the coil line. The current and voltage signals of the coil line are converted and transmitted to the MCU component. The MCU component uses the collected current and voltage signals to analyze the monitoring and early warning information, converts the information into data corresponding to the host computer, and transmits it to the monitoring and early warning output module. The monitoring and early warning output module then transmits the data to the host computer control system via the monitoring and early warning line.

[0038] The structure of an electromagnetic brake is as follows Figure 2 As shown, it consists of an armature 10, a stationary plate 15, and a coil 14. The distance between the working surface 11 of the armature and the working surface 13 of the stationary plate is called the air gap 12. When the coil 14 is energized (i.e., the brake is energized), the armature 10 and the stationary plate 15 are attracted together (i.e., the brake is engaged), and the air gap is at its minimum (zero). When the coil 14 is de-energized (i.e., the brake is de-energized), the armature 10 returns to its original position (i.e., the brake is released), and the air gap is at its maximum.

[0039] The electromagnetic brake air gap distance detection method of this invention includes the following steps:

[0040] Step 1: Data Collection

[0041] Several calibration positions x1, x2, ..., x are set between the armature and the stationary plate of the electromagnetic brake. n The electromagnetic brake armature is fixed at the calibrated position to form an air gap position corresponding to each calibrated position. In this embodiment, when the brake resistance R is 100 ohms and the external power supply voltage is 110V, the air gap (mm) x = {0.0, 0.1, 0.2, 0.3} is set respectively. The brake coil is energized, and the monitoring device records the coil current i of the air gap at each calibrated position in sequence. x and coil voltage u x Data;

[0042] Step 2: Calculate the flux linkage curve for each air gap using the flux linkage calculation formula.

[0043] The flux linkage is calculated using the following formula for the coil voltage u and coil current i recorded for each air gap.

[0044]

[0045] R is the coil resistance, and t is the sampling time.

[0046] After substituting the values, it becomes:

[0047]

[0048] Where x1, x2, ..., x n To set the air gap position, i.e., the air gap height, in mm; i: coil current.

[0049] Unit: A; u: coil voltage, unit: V; Ψ: coil flux linkage, unit: Wb.

[0050] Step 3: Establish a discrete flux linkage-ammeter

[0051] (1) Set several discrete current points i at equal intervals for the brake current. k ={i1, i2, ..., i m},

[0052] After substituting the values, we get: i = {0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8};

[0053] (2) According to the air gap sequence, the above discrete currents i are connected one by one. k Corresponding magnetic chain Ψ x The values ​​are labeled in the discrete flux-current table.

[0054] After labeling the values, as follows Figure 6 As shown;

[0055] Step 4: Determine the location of the point to be detected in the discrete flux linkage-current meter.

[0056] (1) When the coil of the brake under test is energized, the monitoring device records the data of the electromagnetic brake coil voltage u and coil current i;

[0057] (2) Specify the specific current point i of the brake to be tested p =0.38, find i p The time t of point ip and using the formula

[0058] Calculate the corresponding magnetic flux linkage Ψ p =5.2;

[0059] (3) Search p(i) p ,Ψ p The position of point p(i) in the discrete flux linkage-current meter determines the area surrounding p(i). p ,Ψ p Data for the four neighboring points of point Ψ: a(i1,Ψ) a),b(i2,Ψ b ),c(i1,Ψ c ),d(i2,Ψ d ).

[0060] like Figure 4 and Figure 7 As shown, the search is confirmed.

[0061] a(i a ,Ψ a )=(0.3,4.4); b(i b ,Ψ b )=(0.4,4.8); c(i c ,Ψ c ) = (0.3, 5.4);

[0062] d(i d ,Ψ d ) = (0.4, 5.9);

[0063] p(i p ,Ψ p ) = (0.38, 5.2);

[0064] x1 = 0.2; x2 = 0.1;

[0065] i1=i a =i c =0.3; i2=i b =i d =0.4

[0066] (4) Determine the lower limit air gap x1 from points a and b, and determine the upper limit air gap x2 from points c and d.

[0067] Step 5: Calculate the air gap at the detection point using the data from the four nearest points and the upper and lower limit air gaps.

[0068] use Formula (1) calculates the ratio ti of point p on line segment ab.

[0069]

[0070] Using ψ e =(1-t) i )ψ a +t i ψ b Formula (2) calculates the magnetic flux interpolation data Ψ of point p on line segment ab according to the ratio ti. e ,

[0071] ψ e =(1-t) i )ψ a +ti ψ b = (1-0.8)4.4 + 0.8 × 4.8 = 4.72;

[0072] Using ψ f =(1-t) i )ψ c +t i ψ d Formula (3) based on the ratio t i Calculate the magnetic flux interpolation data Ψ of point p on line segment cd. f ,

[0073] ψ f =(1-t) i )ψ c +t i ψ b = (1-0.8)5.4 + 0.8 × 5.9 = 5.8;

[0074] use Formula (4) calculates the ratio t of point p on line segment ef. Ψ ,

[0075]

[0076] Using x p =(1-t) ψ )x1+t ψ x2 according to the ratio t Ψ Calculate the interpolation data x of the air gap at the detection point between the lower limit air gap x1 and the upper limit air gap x2. p ,

[0077] x p =(1-t) ψ )x1+t ψ x2=(1-0.44)×0.2+0.44×0.1=0.156.

[0078] Detection point air gap x p =0.156mm.

[0079] When air gap data x p When the value exceeds the preset range, a warning message will be issued.

[0080] For example: the preset value for brake clearance is 0.10mm, and the current value of the automatically detected air gap is 0.156mm, which exceeds the preset range by 56%, triggering an alarm.

[0081] In summary, the objective of this invention has been achieved.

Claims

1. A method for detecting the air gap distance of an electromagnetic brake, characterized in that: Includes the following steps: Step 1: Data Collection Several calibration positions x1, x2, ..., x are set between the armature and the stationary plate of the electromagnetic brake. n Fix the armature of the electromagnetic brake at the calibrated position to form an air gap position corresponding to each calibrated position. Energize the brake coil and record the coil voltage u and coil current i of the air gap at each calibrated position in sequence. Step 2: Calculate the flux linkage curve for each air gap using the flux linkage calculation formula. The flux linkage is calculated using the following formula for the coil voltage u and coil current i recorded for each air gap. R is the coil resistance, and t is the sampling time. Step 3: Establish a discrete flux linkage-ammeter (1) Set several discrete current points i at equal intervals for the brake current. k ={i1, i2, ..., i m }; (2) According to the air gap sequence, the above discrete current points i are sequentially connected. k Corresponding magnetic flux The values ​​are marked in the discrete flux-current table; Step 4: Determine the location of the point to be detected in the discrete flux linkage-current meter. (1) The coil of the brake to be tested is energized and the coil voltage u and coil current i are recorded; (2) Specify the specific current point i of the brake to be tested p Find out i p The time t of point ip And calculate its corresponding magnetic flux linkage Ψ p : (3) Search p(i) p ,Ψ p The position of point p(i) in the discrete flux linkage-current meter determines the area surrounding p(i). p ,Ψ p Data for the four neighboring points of point Ψ: a(i1,Ψ) a ),b(i2,Ψ b ),c(i1,Ψ c ),d(i2,Ψ d ) (4) Determine the lower limit air gap x1 from points a and b, and determine the upper limit air gap x2 from points c and d; Step 5: Calculate the air gap at the detection point based on the data from the four nearest points and the upper and lower limit air gaps. use Formula (1) calculates the ratio t of point p on line segment ab. i ; Using ψ e =(1-t) i )ψ a +t i ψ b Formula (2) according to the ratio t i Calculate the magnetic flux interpolation data Ψ of point p on line segment ab. e ; Using ψ f =(1-t) i )ψ c +t i ψ d Formula (3) based on the ratio t i Calculate the magnetic flux interpolation data Ψ of point p on line segment cd. f ; use Formula (4) calculates the ratio t of point p on line segment ef. Ψ ; Using x p =(1-t) ψ )x1+t ψ x2 according to the ratio t Ψ Calculate the interpolation data x of the air gap at the detection point between the lower limit air gap x1 and the upper limit air gap x2. p .

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