Elevator hoisting machine braking force self-monitoring method and system

Abstract

The application belongs to the technical field of elevator safety maintenance control, and particularly relates to a kind of elevator hoisting machine braking force self-monitoring method and system, wherein the method comprises: closing hall car door and disabling when elevator is idle; controlling car to run to the same horizontal position of car and counterweight and stably running at preset speed; removing motor current; monitoring motor torque current value, when it is zero, controlling brake to lose power braking; collecting angular velocity signal of deceleration braking section to calculate average angular acceleration; calculating actual braking torque according to torque balance equation and comparing it with preset lower limit value, if it is less than lower limit value, then alarming and disabling. The application also detects up and down braking torque respectively and calculates difference value to determine guide system blocking or poor brake shoe adhesion. The application directly detects dynamic friction braking torque in dynamic braking process, overcomes the risk of misjudgment caused by static detection method replacing dynamic friction with static friction, and improves detection accuracy and elevator safety.

Description

Technical Field

[0001] This invention relates to the field of elevator safety maintenance and control technology, and in particular to a method and system for self-monitoring the power of an elevator traction mechanism. Background Technology

[0002] The elevator traction mechanism brake is a key component for the safe operation of elevators. According to safety standards, when the elevator traction mechanism brake is used as a safety component such as a braking subsystem to stop unexpected car movement or an overspeed protection device, the braking force needs to be tested periodically.

[0003] Patent application CN109540367A discloses a method and system for detecting the braking force of an elevator traction machine brake. The main approach is to test the traction machine by driving the drive unit while the brake is stationary. Another example is patent application CN105905729A, which discloses a big data-based method for monitoring the power of an elevator traction machine. The method involves the following steps: after the brake loses power and engages the traction sheave, the frequency converter drives the traction machine to operate with the brake engaged. The output power of the frequency converter is monitored, and the encoder determines whether the traction machine is rotating. When the encoder senses that the traction machine has started to rotate, the instantaneous power value is recorded.

[0004] The aforementioned existing technologies all have the following drawbacks: First, the tests measure static friction braking torque, not the dynamic friction braking torque that functions during actual emergency braking. All the above methods involve the traction machine being driven by the actuator to attempt rotation after the brake is engaged, testing the critical torque (i.e., maximum static friction torque) at which the brake begins to slip from rest. According to tribological principles, the static friction coefficient is usually greater than the dynamic friction coefficient, meaning static friction force is greater than dynamic friction force. Therefore, a brake that passes the static test may have insufficient braking force during actual dynamic emergency braking, posing a serious safety hazard.

[0005] Second, indirectly estimating power by setting torque current values ​​or monitoring power values ​​ignores the influence of factors such as motor armature reaction, resulting in calibration errors and insufficient detection accuracy.

[0006] Third, it has a single function, only able to output the result of whether the braking force is sufficient, and cannot diagnose specific faults such as guide system jamming or poor brake shoe fit. Summary of the Invention

[0007] This invention proposes a method and system for self-monitoring the power of an elevator traction mechanism, aiming to solve the technical problem of misjudgment risk in existing elevator traction mechanism power detection methods due to the detection of static friction braking torque instead of dynamic friction braking torque.

[0008] In a first aspect, the present invention provides a method for self-monitoring the power of an elevator traction mechanism, comprising: When the elevator is in an unloaded and idle state, close the elevator hall door and car door, and set the elevator to a disabled state; Control the elevator car to the shaft position corresponding to when the car and counterweight are at the same horizontal position, and run stably at a preset speed; Turn off the current to the elevator traction machine motor; Monitor the motor torque current value; when it is zero, control the brake to de-energize and brake. During the elevator deceleration and braking process, the angular velocity signal of the traction machine motor is collected, and the average angular acceleration of the motor in the braking and deceleration phase is calculated. According to the torque balance equation, the actual braking torque of the brake is calculated using the average angular acceleration. If the actual braking torque is less than the preset lower limit of the braking torque, it is determined that the braking torque of the brake is insufficient, an alarm signal is output, and the elevator is kept in a disabled state.

[0009] Furthermore, the calculated average angular acceleration of the motor during the braking deceleration phase is specifically as follows: The collected discrete angular velocity signals are digitally filtered to identify the start and end sampling times of the braking deceleration phase from the filtered angular velocity sequence. The angular velocity values ​​at the start and end sampling times are obtained, and the average angular acceleration is calculated.

[0010] Furthermore, the step of calculating the actual braking torque of the brake using the average angular acceleration based on the torque balance equation includes: When the elevator is going up, the average angular acceleration is multiplied by the total moment of inertia of the empty elevator converted to the traction sheave, and then the torque of the weight difference between the empty car side and the counterweight side converted to the traction sheave is subtracted to obtain the upward braking torque. When the elevator descends, the downward braking torque is obtained by multiplying the average angular acceleration by the total moment of inertia of the unloaded elevator referred to the traction sheave, and adding the torque of the weight difference referred to the traction sheave.

[0011] Furthermore, it also includes: Perform upward braking detection and downward braking detection respectively to obtain the upward braking torque and the downward braking torque; The difference between the upward braking torque and the downward braking torque, the difference between the upward average angular acceleration and the downward average angular acceleration, and the torque converted from the weight difference to the traction sheave are used to calculate the difference between the friction torque of the upward guidance system and the friction torque of the downward guidance system. If the absolute value of the difference between the frictional torque of the upward guide system and the frictional torque of the downward guide system is greater than the preset difference limit, it is determined that the guide system is stuck or the brake shoe is not properly attached to the brake surface, and a maintenance reminder signal is output.

[0012] Furthermore, the difference limit is obtained in advance in the following way: before the elevator is installed and put into use, after confirming that the elevator is in normal operating condition, at least two upward braking tests and downward braking tests are performed, and the difference between the friction torque of the upward guide system and the friction torque of the downward guide system corresponding to each test is obtained. The absolute value is taken and multiplied by a preset safety margin coefficient, and the result is stored in the elevator control system as the difference limit.

[0013] Furthermore, the total moment of inertia and the torque converted to the traction sheave based on the weight difference are obtained from the elevator design documents and stored in advance in the memory of the elevator control system; the torque converted to the traction sheave based on the weight difference is calculated based on the counterweight mass, the empty car mass, the gravitational acceleration, and the diameter of the traction sheave.

[0014] Furthermore, the monitoring of the motor torque current value, when it is zero, controls the brake to de-energize and brake, specifically by: reading the feedback value of the motor torque current in real time through a current sensor or Hall effect current detector set in the motor drive circuit; when the feedback value is zero for a predetermined time interval, it is confirmed that the motor torque current has returned to zero, and then the brake is controlled to de-energize and brake.

[0015] Furthermore, the position signal of the hoistway position corresponding to the car and counterweight being at the same horizontal position is obtained from the hoistway position detection device of the elevator system. The hoistway position detection device includes a leveling sensor, a magnetic ruler, or an absolute encoder installed in the hoistway.

[0016] Furthermore, the above steps are repeated periodically at preset time intervals, which are set according to the elevator operating frequency or calendar time.

[0017] Secondly, the present invention provides an elevator traction mechanism power self-monitoring system, comprising: An elevator traction machine includes a traction sheave, a motor, and a brake. The traction sheave is connected to the car and the counterweight via a suspension system. An encoder, mechanically connected coaxially to the motor, is used to acquire the angular velocity signal of the motor; The shaft position detection device is installed inside the elevator shaft and is used to detect the position of the car in the shaft; A current detection device is installed in the motor's drive circuit to monitor the motor's torque current value; The elevator control system is electrically connected to the motor, the brake, the encoder, the shaft position detection device, and the current detection device. The elevator control system includes a memory and a processor. The memory stores a preset lower limit value of braking torque, the total moment of inertia of the unloaded elevator converted to the traction sheave, the absolute value of the torque of the weight difference between the unloaded car side and the counterweight side converted to the traction sheave, and a preset difference limit value. When the processor executes the program stored in the memory, it implements the steps of the method.

[0018] The technical effects of the technical solution disclosed in this invention are: (1) The present invention ensures that the brake is engaged only after confirming that the motor torque current is completely zero, so that the brake can generate braking torque independently without being disturbed by the residual torque of the motor. This enables the accurate detection of dynamic friction braking torque during the actual operation of the elevator, and fundamentally avoids the risk of misjudgment caused by substituting static friction braking torque for dynamic friction braking torque in the existing static detection method.

[0019] (2) The present invention uses an encoder to collect the angular velocity signal during the actual braking process, and obtains the angular acceleration through digital filtering and differential calculation. Then, the specific value of the braking torque is quantitatively calculated through the torque balance equation, which avoids the influence of motor armature reaction and calibration error introduced by setting the torque current value equivalent torque in the prior art.

[0020] (3) By detecting the braking torque in the upward and downward directions and calculating the difference, the present invention can effectively separate the difference in friction torque of the guide system in the upward and downward directions. When the difference exceeds the normal range, it can be accurately determined that the guide system is stuck or the brake shoe is not properly attached to the brake surface, providing elevator maintenance personnel with accurate fault diagnosis reference information.

[0021] (4) By performing the test when the car and the counterweight are at the same level, the present invention eliminates the interference of the mass difference of the suspension systems on both sides of the traction wheel on the calculation results, and further improves the calculation accuracy of the braking torque. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the principle of a self-monitoring method for the power of an elevator traction mechanism proposed in an embodiment of the present invention; Figure 2 This is a flowchart illustrating a self-monitoring method for the power of an elevator traction mechanism proposed in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached diagram: 1-Traction sheave; 2-Car; 3-Counterweight; 4-Suspension system. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] To address the technical problem mentioned in the background art regarding the risk of misjudgment in elevator traction mechanism power detection methods due to the substitution of static friction braking torque for dynamic friction braking torque, this invention provides an elevator traction mechanism power self-monitoring method. Before the elevator is installed and put into use, the following parameters are obtained from the elevator design documents and pre-stored in the memory of the elevator control system: (1) The total moment of inertia J of an unloaded elevator converted to the traction sheave. The physical meaning of J is: when the elevator is in an unloaded state, the equivalent moment of inertia of all moving parts of the elevator (including the traction sheave, motor rotor, suspension system, car, counterweight, etc.) converted to the traction sheave shaft. For a specific elevator specification, J is a constant and can be calculated according to the principle of conservation of kinetic energy using the component mass and moment of inertia parameters in the elevator design documents.

[0026] (2) The absolute value of the torque on the traction sheave converted from the weight difference between the unloaded car side and the counterweight side. . The physical meaning is: when the elevator is unloaded, the weight on the car side is not equal to the weight on the counterweight side (usually the counterweight side is slightly heavier than the unloaded car side), and the torque generated by this weight difference is related to the rotation direction of the traction sheave. Calculate using the following formula: ; in, For counterweight mass, For the weight of the empty car, It is the acceleration due to gravity. The diameter is the traction sheave. For a specific elevator, it is a constant.

[0027] (3) Preset lower limit of braking torque. This value is the minimum braking torque required by the brake calculated according to GB 7588 "Safety Code for Elevator Manufacturing and Installation" and related safety standards. It is usually taken as 1.5 times or 2 times the torque converted to the traction sheave under the rated load of the elevator. The specific value is determined according to the rated load capacity, rated speed, traction ratio and other parameters of the elevator.

[0028] (4) Preset difference limit. This value is used to determine whether the difference in friction torque between the up and down guide systems is abnormal. For the method of obtaining it, please refer to the detailed description of the determination of the up and down difference below.

[0029] The complete process of the elevator traction mechanism power self-monitoring method of the present invention is described in detail below. This embodiment uses a complete unidirectional (upward) braking force detection as an example for illustration; the process of downward braking force detection is symmetrical to that of upward. (See reference...) Figure 1 and Figure 2 As shown.

[0030] Step 1: Triggering and Preparation. The elevator control system first determines whether the elevator simultaneously meets the following two conditions: (a) The elevator is in an unloaded state, i.e., there are no passengers or goods in the car. This information is obtained through a weighing device in the car (such as a pressure sensor installed at the bottom of the car). The weighing device outputs an electrical signal proportional to the car's load to the elevator control system. The elevator control system determines whether the load is zero or less than the unloaded threshold based on this signal; (b) The elevator is in an idle state, i.e., there are no external call signals, no internal selection signals, and no running instructions within a predetermined time interval (e.g., 30 seconds). The elevator control system determines whether this condition is met by checking its internal call signal register and running status register. When both conditions are met, the elevator control system sends a door closing command to the door operator controller, closing the elevator hall door and car door, and confirms through the door lock circuit that both the hall door and car door are completely closed. Subsequently, the elevator control system sets the elevator to a disabled state (i.e., sets a disabled flag bit inside the control system, no longer responding to any external call or internal selection signals) to prevent external call or internal selection signals from interrupting the detection process.

[0031] Step Two: Pre-run. The elevator control system obtains the current position of the car in the shaft through the shaft position detection device. Specifically, the shaft position detection device transmits the detected position signal (such as the switch signal of the leveling sensor or the encoded signal of the magnetic ruler) to the elevator control system, which calculates the current absolute position of the car according to the preset shaft position mapping table.

[0032] Subsequently, the elevator control system sends a speed command to the motor driver, controlling the motor to drive the traction sheave to rotate, causing the car to travel along the hoistway to the hoistway position corresponding to when the car and counterweight are at the same horizontal level. This position is determined as follows: the elevator control system calculates the absolute position value of the car when it is at the same horizontal level with the counterweight based on pre-stored hoistway data (including the height of each floor, the total height of the hoistway, the initial positions of the car and counterweight, etc.), and uses this as the target position.

[0033] The physical significance of this chosen position is that when the car and counterweight are at the same horizontal level, the lengths of the suspension systems on both sides of the traction sheave are equal, and the mass of the suspension systems themselves is equal on both sides. Therefore, the mass difference of the suspension systems does not have an additional impact on the torque balance on both sides of the traction sheave, eliminating the systematic error introduced by the mass distribution of the suspension systems into the subsequent braking torque calculation results. The elevator control system performs closed-loop control based on the position signal fed back in real time by the shaft position detection device. When the car reaches the target position, the elevator control system stops position adjustment and confirms that the car has accurately reached that position.

[0034] Subsequently, the elevator control system sends a low-speed command to the motor driver, controlling the motor to operate at a preset speed. Drive the traction sheave to operate stably. A relatively low speed value (0.2 m / s to 0.5 m / s) is selected, which is pre-stored in the elevator control system's memory. This speed selection takes into account two aspects: firstly, This ensures that the encoder collects a sufficient number of angular velocity signals during the braking and deceleration phase (usually no less than 10 sampling points) for the elevator control system to perform digital filtering and differential calculations; on the other hand, because... The lower friction distance between the brake shoes and the brake surface during brake engagement effectively reduces wear on the brake shoes during the detection process. The elevator control system uses the angular velocity signal fed back from the encoder for closed-loop speed control (such as PID control) to stabilize the elevator speed at a constant value. The value is monitored until the angular velocity fluctuation remains within ±5% for 0.5 seconds, confirming that the elevator has entered a stable operating state.

[0035] Step 3: Force Removal. The elevator control system sends a torque command (torque setpoint is zero) to the motor driver, canceling the motor current and making the motor's output torque zero. At this time, the traction sheave is no longer driven by the motor's torque, and the car and counterweight lose balance under the influence of gravity difference. Driven by gravity difference, the car begins to accelerate along the hoistway (but since this stage lasts for a very short time, the acceleration and displacement are extremely small; see Step 4 for immediate response).

[0036] It should be noted that the time interval from the cancellation of the motor current to the torque current feedback returning to zero is extremely short (usually within a few milliseconds). Furthermore, since this method has already controlled the elevator's preset speed to an extremely low value (0.2 m / s to 0.5 m / s) in step two, the car's displacement within this extremely short time interval will not exceed 1 mm, which is far less than the stopping distance allowed in elevator safety regulations (usually tens of centimeters to several meters), and will not affect the safe operation of the elevator. In addition, in normal elevator control logic, when the elevator detects that the car has moved unexpectedly beyond a preset threshold (e.g., 100 mm), the elevator control system will immediately trigger additional stopping devices such as safety clamps or rope clamps to further ensure safety.

[0037] Step Four: Braking. The elevator control system monitors the motor's torque current feedback value in real time through a current detection device. This current detection device is located in the motor's drive circuit (e.g., any one of the three phases U, V, and W, or on the DC bus side). The elevator control system continuously reads the analog signal output by the current detection device and converts it into a digital current value using an analog-to-digital converter (ADC). When the elevator control system detects that the torque current feedback value remains zero for a predetermined time interval (e.g., 10 milliseconds, i.e., multiple consecutive sampling points) (i.e., the digital current value is less than a preset zero current threshold, such as 1% of the rated current), it confirms that the motor's torque current has completely returned to zero, meaning the motor is no longer outputting any torque.

[0038] After confirming that the motor torque current has returned to zero, the elevator control system immediately sends a power-off command to the brake (i.e., cuts off the power supply circuit to the brake's electromagnet), controlling the brake to lose power. The brake is a power-off braking type, and its working principle is as follows: During normal operation, the electromagnet is energized, generating electromagnetic force that overcomes the spring force, causing the brake shoes to separate from the braking surface; after power loss, the electromagnetic force disappears, and the spring pushes the brake shoes to immediately grip the braking surface (the braking surface of the traction sheave or the brake disc on the motor output shaft), generating braking torque. The elevator decelerates under the combined action of the brake's braking torque and the weight difference torque between the car and the counterweight, stopping within 0.5 meters.

[0039] The purpose of waiting until the motor torque current feedback reaches zero before applying the brake in this step is to ensure that the motor is completely not outputting torque when the brake is engaged. This avoids the residual torque output by the motor from superimposing with the braking torque of the brake, which would interfere with the subsequent calculation results of the braking torque. If the brake is engaged before the motor torque current has returned to zero, the subsequently calculated braking torque will actually be the superposition of the braking torque of the brake and the residual torque of the motor, leading to calculation errors.

[0040] Step 5: Angular Acceleration Acquisition. During elevator deceleration and braking, the encoder acquires the motor's angular velocity signal in real time according to a preset sampling frequency (e.g., 500 Hz or 1000 Hz), and feeds back the acquired angular velocity signal to the elevator control system in real time via pulse sequence or digital communication. For incremental encoders, the elevator control system calculates the angular velocity by measuring the number of pulses per unit time; for absolute encoders, the elevator control system directly reads the digital angle value and calculates the difference to obtain the angular velocity.

[0041] The elevator control system receives discrete angular velocity sequences from the encoder. ,in These are the sampling times, The values ​​represent the angular velocity values ​​at each sampling time. The elevator control system first performs digital filtering on this discrete angular velocity sequence to eliminate noise interference. Digital filtering can be performed using a moving average filtering method, which takes the arithmetic mean of 5 consecutive sampling points as the filtered value for that point; or a low-pass filtering method (first-order RC low-pass digital filter) can be used, with the filter cutoff frequency set to 1 / 10 to 1 / 5 of the sampling frequency, the specific value of which is determined based on the mechanical vibration frequency of the elevator system.

[0042] Subsequently, the elevator control system performs differential calculations on the filtered angular velocity sequence. The starting sampling time of the braking deceleration phase is then identified from the filtered angular velocity sequence. and the time to terminate sampling Start sampling time The identification method is as follows: starting from the first sampling point after the brake power failure command is issued, the angular velocity values ​​of adjacent sampling points are compared sequentially. When the angular velocity values ​​of three consecutive sampling points are all lower than the stable operating speed, the identification method is determined. When the corresponding angular velocity value shows a monotonically decreasing trend, the first descent point is defined as the initial sampling time. Termination of sampling time The identification method is as follows: starting from the initial sampling time, continue monitoring the angular velocity value. When the angular velocity value first falls below a predetermined threshold (e.g., 0.01 rad / s), the previous sampling point is defined as the termination sampling time. .

[0043] Then calculate the average angular acceleration during the braking deceleration phase using the following formula: ; in, This is the starting sampling time for the braking deceleration phase. This is the end sampling time of the braking deceleration phase. The angular velocity value at the initial sampling time. This represents the angular velocity value at the point where sampling ceases. Because the angular velocity continuously decreases during braking and deceleration, The value is negative, and its absolute value indicates the severity of braking deceleration.

[0044] Step Six: Braking Torque Calculation. The elevator control system calculates the actual braking torque of the brake based on the torque balance equation. The following detailed derivation uses the elevator's upward movement as an example; the downward movement is symmetrical.

[0045] Taking the elevator's direction of travel as positive, when the elevator goes up, the car moves upward and the counterweight moves downward. angular acceleration during braking deceleration It is a negative value.

[0046] During the elevator's upward braking process, the torque acting on the traction sheave includes: (a) Braking torque of the brake, in the opposite direction to the running direction (i.e., in the negative direction), with a value marked with a sign. ,in This represents the magnitude of the braking torque (positive value). (b) Weight difference torque: The weight on the counterweight side is greater than the weight on the unloaded car side, and the direction is opposite to the running direction (i.e., along the negative direction). Its sign value is... ,in This represents the magnitude of the weight difference torque (positive value). (c) The frictional torque of the guiding system, in the opposite direction to the running direction (i.e., along the negative direction), has a sign value. ,in This refers to the magnitude of the frictional torque (positive value), including the frictional force between the car guide shoes and the guide rails, and the frictional force between the suspension system and the traction wheel.

[0047] According to the differential equation of rigid body rotation about a fixed axis (the net torque equals the product of the moment of inertia and the angular acceleration), we have: ; because Since the value is negative, after rearranging the terms, we get: ; After digital discretization, With average angular acceleration Approximate substitution: ; Similarly, when the elevator is descending, taking the elevator's direction of travel (downward) as the positive direction, the car moves downward while the counterweight moves upward, and the angular velocity... >0, angular acceleration during braking deceleration phase It is a negative value.

[0048] During downward braking, the torque acting on the traction sheave includes: (a) Braking torque of the brake, in the opposite direction to the running direction (i.e., in the negative direction), with a sign value. ; (b) Weight difference torque: The weight on the counterweight side is greater than the weight on the unloaded car side, but the direction is the same as the running direction (i.e., along the positive direction, auxiliary downward). The value with a sign is... ; (c) The frictional torque of the guiding system, in the opposite direction to the running direction (i.e., in the negative direction), with a sign value of .

[0049] According to the differential equation of rigid body rotation about a fixed axis: ; Rearranging the terms, we obtain the braking torque of the downward brake: ; After digital discretization: ; In a normally operating elevator, the frictional torque of the guide system... and The value relative to the braking torque of the brake is usually small (2% to 5%) and can be neglected in engineering calculations. and The above formula simplifies to: When the elevator goes up: ; When the elevator is descending: ; in, This is the upward braking torque of the brake during upward travel (positive value). This is the downward braking torque of the brake during downward movement (positive value). This represents the total moment of inertia of the unloaded elevator referred to the traction sheave. This represents the average angular acceleration (negative value) during the upward braking deceleration phase. This represents the average angular acceleration (negative value) during the downward braking and deceleration phase. It is the absolute value (positive value) of the torque on the traction sheave, calculated from the weight difference between the unloaded car side and the counterweight side.

[0050] The physical meaning is as follows: When braking upwards, the braking torque needs to overcome the inertial torque (generated by deceleration) and subtract the auxiliary effect of the gravitational difference torque (the gravitational difference torque helps with braking when moving upwards). When braking downwards, the braking torque needs to overcome the inertial torque and additionally overcome the resisting effect of the gravitational difference torque (the gravitational difference torque hinders braking when moving downwards).

[0051] Step 7: Comparison and determination. The elevator control system reads the preset lower limit value of braking torque from the memory. The calculated actual braking torque and Compare them.

[0052] like If the braking torque of the brake is determined to meet the requirements for safe operation, the elevator control system will record the test results (including test time, braking torque value, and judgment result) in the log file in the memory and mark it as normal.

[0053] like If the braking torque of the brake is determined to be insufficient, the elevator control system shall immediately perform the following operations: (a) send an alarm message to the remote monitoring platform through the elevator IoT module (such as a 4G / 5G communication module or a wired network module). The alarm message includes the elevator number, detection time, measured braking torque value, and lower limit of braking torque; (b) display the fault code through the human-machine interface (such as an LCD screen) inside the elevator; (c) maintain the elevator in a disabled state (i.e., keep the disabled flag in a valid state), prohibit the elevator from being put into normal operation until maintenance personnel arrive at the site to confirm and eliminate the fault. Then, the disabled flag is cleared by manual reset operation (such as by inputting a reset command through a dedicated maintenance controller) to restore elevator operation.

[0054] Step 8: Recovery. The elevator control system sends a speed command to the motor driver, controlling the motor to drive the traction sheave to rotate, causing the car to move to the nearest floor leveling position. After the elevator control system confirms that the car has reached the leveling position through the shaft position detection device (i.e., the leveling sensor sends a signal indicating arrival), it cancels the elevator's disabled state (clears the disabled flag), and the elevator resumes normal operation. The elevator control system restarts responding to external calls and internal selection signals, and sends an opening command to the door operator to open the hall door and car door.

[0055] Step Nine: Periodic Repetition. The elevator control system automatically triggers steps one through eight at preset time intervals. The preset time interval is set based on the elevator's operating frequency (e.g., triggering once every 2000 runs) or calendar time (e.g., triggering once every 7 or 30 days), or triggering when either of these conditions is met simultaneously. Specifically, the elevator control system has an internal run counter. The counter increments by 1 after each elevator run. A detection is triggered when the counter value reaches a preset run count threshold (e.g., 2000 runs). Simultaneously, the elevator control system has an internal calendar timer. A detection is triggered when the time since the last detection reaches a preset calendar time threshold (e.g., 7 or 30 days). After the detection is complete, the corresponding counter or timer resets, and the next round of counting begins.

[0056] In addition to the aforementioned unidirectional braking force detection, this invention also provides an upward and downward differential value determination function to diagnose faults such as steering system jamming or poor brake shoe contact. The specific implementation of this function is as follows: During one self-monitoring cycle of the elevator, the elevator control system sequentially performs upward braking detection and downward braking detection. The upward braking detection is performed according to steps one through six above (the car moves upwards), calculating the upward braking torque. The average angular acceleration during the upward braking deceleration phase The downward braking test is performed according to steps one through six above (as the car moves downwards), and the downward braking torque is calculated. The average angular acceleration during the downward braking deceleration phase Between the two tests, the elevator control system controls the car to return to the middle position of the shaft before performing a reverse run test.

[0057] Subsequently, the elevator control system calculates the frictional torque of the upward guiding system according to the following derivation. Frictional torque with the down-steering system The difference: .

[0058] The elevator control system will calculate the The absolute value and the preset difference limit Compare them.

[0059] Difference Limit The pre-acquisition method is as follows: Before the elevator is installed and put into use, the commissioning personnel enter the self-learning mode through the commissioning interface of the elevator control system to confirm that the elevator is in normal operating condition (i.e., confirm that the guide system is not obstructed and the brake shoes are in good contact with the brake surface). At least two (preferably three to five) upward brake tests and downward brake tests are performed according to the above method, and the corresponding data for each set of tests are obtained. Value. Under normal conditions, the frictional torques of the upward and downward guiding systems are basically symmetrical. The value should be a small value (theoretically close to zero). The elevator control system takes the values ​​obtained from each group of tests. The absolute value is used to calculate the arithmetic mean, which is then multiplied by a safety margin factor (1.5 to 2.0, which is pre-stored in memory) to determine the difference limit. It is stored in the memory of the elevator control system.

[0060] like If the elevator's guiding system is found to be jammed (e.g., abnormally increased friction between the car guide shoes and guide rails, possibly due to guide shoe wear, poor guide rail lubrication, or guide rail installation misalignment) or if the brake shoes are not properly fitted to the brake surface (e.g., inconsistent gaps on both sides of the brake shoes leading to asymmetrical braking torque in both directions, possibly due to improper brake mechanical adjustment or uneven wear of the brake shoes), the elevator control system will output a maintenance alert signal. This signal will send fault type information (including a preliminary assessment of guiding system jamming or poor brake shoe fit) to maintenance personnel via the elevator IoT module. This information will also be recorded in the elevator control system's log file. This maintenance alert signal does not disable the elevator; it only serves as a warning to remind maintenance personnel to conduct targeted checks during the next scheduled maintenance.

[0061] like If the guide system and brake shoe are found to be in normal contact, the elevator control system 8 records the test result and continues to operate normally.

[0062] Based on the same inventive concept, embodiments of the present invention also provide an elevator traction mechanism power self-monitoring system, comprising: The traction sheave 1 connects the car 2 and the counterweight 3 via a suspension system 4 (traction wire rope or steel belt). The car 2 and the counterweight 3 are suspended on both sides of the traction sheave 1. One end of the suspension system 4 is fixed to the top of the car 2, and the other end passes around the traction sheave 1 and is fixed to the top of the counterweight 3.

[0063] The motor is mechanically connected to the traction sheave 1 (e.g., via a gearbox or direct drive) to drive the traction sheave 1 to rotate, thereby causing the car 2 and counterweight 3 to move up and down in the hoistway. The motor is preferably a permanent magnet synchronous motor or an asynchronous motor.

[0064] The brake is located at the output end of the motor or on the shaft of the traction sheave 1. It is a power-off braking type brake (i.e., when energized, the electromagnet engages and releases the brake shoes; when de-energized, the spring pushes the brake shoes to engage the brake surface), used to generate braking torque by engaging the brake surface when power is lost. The brake typically includes a brake electromagnet, a brake spring, brake shoes, and a brake surface (brake disc or brake wheel).

[0065] An encoder, mechanically connected coaxially to the motor (e.g., directly connected to the motor's output shaft via a coupling), is used to acquire the motor's rotational angular velocity signal in real time and feed the angular velocity signal back to the elevator control system. The encoder is preferably an incremental encoder or an absolute encoder, and its resolution should meet the accuracy requirements of angular velocity measurement.

[0066] A current detection device, installed in the motor's drive circuit, is used to monitor the motor's torque current value in real time. The current detection device is preferably a current sensor (such as a Hall effect current sensor) or a sampling resistor, and its output signal is a voltage or current signal proportional to the motor's torque current.

[0067] A shaft position detection device, installed inside the elevator shaft, is used to detect the real-time position of the car 2 within the shaft. The shaft position detection device may include a leveling sensor (such as a permanent magnet sensor or photoelectric sensor), a magnetic scale, or an absolute encoder installed within the shaft. The leveling sensor is typically located at the leveling position of each floor, emitting a position signal when a magnetic shield or light-shielding plate on the car 2 passes by.

[0068] The elevator control system is electrically connected to the motor, brake, encoder, current detection device, and hoistway position detection device via signal lines. The elevator control system includes a memory and a processor (such as a PLC, microcontroller, or embedded industrial computer). The memory stores preset lower limits for braking torque, the total moment of inertia of the unloaded elevator referred to the traction sheave, the absolute value of the torque calculated from the weight difference between the unloaded car side and the counterweight side referred to the traction sheave, and preset difference limits. The processor executes the program stored in the memory to implement the steps of the elevator traction mechanism power self-monitoring method of this invention.

[0069] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A method for self-monitoring the power of an elevator traction mechanism, characterized in that, include: When the elevator is in an unloaded and idle state, close the elevator hall door and car door, and set the elevator to a disabled state; Control the elevator car to the shaft position corresponding to when the car and counterweight are at the same horizontal position, and run it stably at a preset speed; Turn off the current to the elevator traction machine motor; Monitor the motor torque current value; when it is zero, control the brake to de-energize and brake. During the elevator deceleration and braking process, the angular velocity signal of the traction machine motor is collected, and the average angular acceleration of the motor in the braking and deceleration phase is calculated. According to the torque balance equation, the actual braking torque of the brake is calculated using the average angular acceleration. If the actual braking torque is less than the preset lower limit of the braking torque, it is determined that the braking torque of the brake is insufficient, an alarm signal is output, and the elevator is kept in a disabled state.

2. The method according to claim 1, characterized in that, The calculated average angular acceleration of the motor during the braking deceleration phase is specifically as follows: The collected discrete angular velocity signals are digitally filtered to identify the start and end sampling times of the braking deceleration phase from the filtered angular velocity sequence. The angular velocity values ​​at the start and end sampling times are obtained, and the average angular acceleration is calculated.

3. The method according to claim 1, characterized in that, The step of calculating the actual braking torque of the brake based on the torque balance equation and the average angular acceleration includes: When the elevator is going up, the average angular acceleration is multiplied by the total moment of inertia of the empty elevator converted to the traction sheave, and then the torque of the weight difference between the empty car side and the counterweight side converted to the traction sheave is subtracted to obtain the upward braking torque. When the elevator descends, the downward braking torque is obtained by multiplying the average angular acceleration by the total moment of inertia of the unloaded elevator referred to the traction sheave, and adding the torque of the weight difference referred to the traction sheave.

4. The method according to claim 3, characterized in that, Also includes: Perform upward braking detection and downward braking detection respectively to obtain the upward braking torque and the downward braking torque; The difference between the upward braking torque and the downward braking torque, the difference between the upward average angular acceleration and the downward average angular acceleration, and the torque converted from the weight difference to the traction sheave are used to calculate the difference between the friction torque of the upward guidance system and the friction torque of the downward guidance system. If the absolute value of the difference between the frictional torque of the upward guide system and the frictional torque of the downward guide system is greater than the preset difference limit, it is determined that the guide system is stuck or the brake shoe is not properly attached to the brake surface, and a maintenance reminder signal is output.

5. The method according to claim 4, characterized in that, The difference limit is obtained in advance in the following way: before the elevator is installed and put into use, after confirming that the elevator is in normal operating condition, at least two upward braking tests and downward braking tests are performed, and the difference between the friction torque of the upward guide system and the friction torque of the downward guide system corresponding to each test is obtained. The absolute value is taken and multiplied by a preset safety margin coefficient, and the result is stored in the elevator control system as the difference limit.

6. The method according to claim 3, characterized in that, The total moment of inertia and the torque converted to the traction sheave based on the weight difference are obtained from the elevator design documents and stored in advance in the memory of the elevator control system; the torque converted to the traction sheave based on the weight difference is calculated based on the counterweight mass, the empty car mass, the gravitational acceleration and the diameter of the traction sheave.

7. The method according to claim 1, characterized in that, The monitoring of motor torque current value, when it is zero, controls the brake to de-energize and brake. Specifically, the feedback value of motor torque current is read in real time by a current sensor or Hall effect current detector set in the motor drive circuit. When the feedback value is zero for a predetermined time interval, it is confirmed that the motor torque current has returned to zero, and then the brake is de-energized and braked.

8. The method according to claim 1, characterized in that, The position signal of the hoistway position when the car and the counterweight are at the same horizontal position is obtained from the hoistway position detection device of the elevator system. The hoistway position detection device includes a leveling sensor, a magnetic ruler, or an absolute encoder installed in the hoistway.

9. The method according to claim 1, characterized in that, The above steps are repeated periodically at preset time intervals, which are set according to the elevator operating frequency or calendar time.

10. A self-monitoring system for elevator traction mechanism power, characterized in that, include: An elevator traction machine includes a traction sheave, a motor, and a brake. The traction sheave is connected to the car and the counterweight via a suspension system. An encoder, mechanically connected coaxially to the motor, is used to acquire the angular velocity signal of the motor; The shaft position detection device is installed inside the elevator shaft and is used to detect the position of the car in the shaft; A current detection device is installed in the motor's drive circuit to monitor the motor's torque current value; An elevator control system is electrically connected to the motor, the brake, the encoder, the shaft position detection device, and the current detection device, respectively. The elevator control system includes a memory and a processor. The memory stores a preset lower limit value of braking torque, the total moment of inertia of the unloaded elevator converted to the traction sheave, the absolute value of the torque of the weight difference between the unloaded car side and the counterweight side converted to the traction sheave, and a preset difference limit value. When the processor executes the program stored in the memory, it implements the steps of the method as described in any one of claims 1 to 9.

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