Escalator full load braking performance evaluation method

Abstract

The present application belongs to the technical field of escalators, and relates to a method for evaluating the braking performance of an escalator under full load, which first establishes an initial equivalent conversion relationship between the no-load braking distance and the full-load braking distance based on the braking test data of the same type of escalator under no-load and full-load conditions, then identifies the key components involved in the braking energy dissipation of the escalator, analyzes the equivalent friction coefficients of the key components under no-load and full-load conditions respectively, generates a correction factor based on the difference between the equivalent friction coefficients under no-load and full-load conditions, and corrects the initial equivalent conversion relationship, finally obtains the no-load braking distance of the target escalator under the current state, predicts the full-load braking distance of the target escalator based on the corrected equivalent conversion relationship, and includes the service state information of the target escalator into the safety compliance evaluation of the prediction result, effectively improving the prediction accuracy and reliability of the full-load braking distance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of escalators, and relates to an evaluation method for the braking performance of an escalator under full load. BACKGROUND

[0002] As an important vertical transportation tool in public places, the reliability of the braking performance of an escalator is directly related to the personal safety of passengers, and the advantages and disadvantages of the performance under full load are concentrated in whether the stopping distance meets the safety standards. Therefore, accurate evaluation of the braking distance of an escalator under full load is a key link in the safety inspection of special equipment.

[0003] At present, the existing technical solutions in this field mainly fall into two categories: the first category is a direct test method, for example, an automatic action capture method and device for an escalator disclosed in Chinese Patent Publication No. CN108975119A, which detects the current value of the motor and the distance value between itself and the preset reference point in real time, judges the starting point of braking according to the continuous reduction of the current, records the first distance value, judges the stopping point according to the distance change being less than a threshold value, and records the second distance value, and obtains the stopping distance by calculating the difference between the two values. The method can accurately test the stopping distance of the escalator under full load, and is simple and reliable to operate.

[0004] The second category is an indirectly improved test method, for example, a measurement method for the stopping distance of an escalator disclosed in Chinese Patent Publication No. CN112320550B, which sequentially performs empty load running, empty load braking without braking, empty load braking with braking, and one-time light load braking test, collects parameters such as speed, power and average deceleration, and substitutes them into a stopping distance conversion formula to calculate the full load stopping distance, thereby avoiding the use of a large number of weights and saving manpower and resources.

[0005] However, the existing technology, especially the calculation method represented by the measurement method for the stopping distance of an escalator disclosed in Chinese Patent Publication No. CN112320550B, still has the following limitations: 1. The existing technology relies on a fixed physical formula to calculate the full load braking distance, and the underlying logic implicitly assumes that the equivalent friction characteristics of the entire braking system of the escalator remain unchanged under empty load, light load and full load. However, in actual situations, the friction behavior of key components such as the brake, the step chain and the guide rail will change nonlinearly with factors such as load pressure, ignoring the differences in friction coefficients under different working conditions, which may lead to an increase in calculation errors and fundamental limitations in the universality and precision of the fixed physical formula.

[0006] 2. The existing technology only calculates based on instantaneous parameters from a single test, lacks consideration of the service state of different escalators, cannot distinguish the differences in braking performance baselines between new and old equipment of the same type, and lacks individual adaptability and forward-looking warning capabilities, which may result in missed or false judgments.

[0007] 3. The prior art lacks a no-load and full-load braking dynamic response consistency criterion based on synchronous comparative test verification, and a kinematics physical constraint tolerance criterion, resulting in a lack of physical basis for the equivalent conversion relationship, weak reliability and explainability. SUMMARY

[0008] In view of this, to solve the problems raised in the background art, an escalator full-load braking performance evaluation method is proposed.

[0009] The purpose of the present application can be achieved by the following technical solutions: The present application provides an escalator full-load braking performance evaluation method, comprising: based on the braking test data of the same type of escalator under no-load and full-load working conditions, establishing an initial equivalent conversion relationship between the no-load braking distance and the full-load braking distance.

[0010] Identify the key components involved in the braking energy dissipation of the escalator, analyze the equivalent friction coefficients of the key components under no-load and full-load working conditions respectively, and generate a correction factor based on the difference between the equivalent friction coefficients under no-load and full-load working conditions to correct the initial equivalent conversion relationship, and obtain the corrected equivalent conversion relationship.

[0011] Obtain the no-load braking distance of the target escalator under the current state, predict the full-load braking distance of the target escalator based on the corrected equivalent conversion relationship, and evaluate the safety compliance of the prediction result.

[0012] Compared with the prior art, the present application has the following advantages: (1) The present application sets up a double-checking mechanism, and only when the physical constraint tolerance judgment is consistent with the dynamic response judgment, can the initial equivalent conversion relationship between the no-load braking distance and the full-load braking distance be established, ensuring that the data set involved in the initial conversion relationship construction has authenticity and reliability, and improving the accuracy of the conversion relationship from the source.

[0013] (2) The present application identifies the key components and inverses their equivalent friction coefficients under no-load and full-load, generates a correction factor based on the difference between the equivalent friction coefficients under the two working conditions, quantifies and compensates for the nonlinear load effect of the escalator braking system friction, and corrects the initial equivalent conversion relationship, effectively improving the prediction accuracy and reliability of the full-load braking distance.

[0014] (3) The present application incorporates the service state information of the target escalator into the safety compliance evaluation process of the full-load braking distance, realizes the individualization and dynamicization of the safety evaluation standard, can give a forward-looking warning for performance degradation, and effectively avoids missed or false judgments. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings described in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0016] Figure 1 The method of the present application is implemented in the flow chart.

[0017] Figure 2 The constraint logic diagram is established for the initial equivalent conversion relationship of the present application.

[0018] Figure 3 The equivalent friction coefficient inversion logic diagram of the present application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0020] Please refer to Figure 1 The present application provides an escalator full load braking performance evaluation method, which comprises the following steps: S1. Based on the braking test data of the same type of escalator under no-load and full-load working conditions, an initial equivalent conversion relationship between the no-load braking distance and the full-load braking distance is established.

[0021] Please refer to Figure 2 To establish a reliable initial equivalent conversion relationship, the present application first needs to obtain reference data through comparative test, and double-verify the data quality to ensure that the physical basis of subsequent relationship establishment is reliable. The specific implementation process is as follows: perform synchronous comparative test, respectively collect the first braking distance and the first braking deceleration change sequence of the same type of escalator under laboratory environment when the escalator is in no-load emergency braking, and the second braking distance and the second braking deceleration change sequence of the same type of escalator under laboratory environment when the escalator is in full-load emergency braking.

[0022] Directly using the original test data to construct the initial equivalent conversion relationship may have risks, so the effectiveness of the data and the consistency of the braking system response need to be checked. This process contains two layers of verification: physical constraint tolerance verification: based on the classical kinematics principle, the braking distance and the braking average deceleration should satisfy the basic relationship of , wherein is the braking distance, is the braking initial speed, The average braking deceleration is used to calculate the first and second average braking decelerations under no-load and full-load conditions, respectively. It is then determined whether the deviation between the measured braking distance and the theoretical distance calculated from the average braking deceleration is within the preset physical constraint tolerance. For example, the deviation should not exceed ±5% of the measured braking distance. This verification is used to exclude invalid data due to gross measurement errors or severe data distortion.

[0023] Dynamic response consistency verification: The dynamic characteristics of the braking system should be load-invariant. By comparing the waveform, peak value, slope, and other trend characteristics of the first and second braking deceleration change sequences, it is determined whether the dynamic responses of no-load emergency braking and full-load emergency braking are consistent. Specifically, the two change sequences can first be aligned on the time axis, and then linear interpolation can be used to unify them to the same sampling frequency. Subsequently, the normalized cross-correlation coefficient of the two change sequences is calculated. When the normalized cross-correlation coefficient is greater than 0.85, the dynamic response is considered consistent, indicating that the dynamic characteristics of the braking system have not changed substantially under different loads, thus satisfying the premise of establishing a simple proportional relationship.

[0024] The experimental data are considered valid and applicable for constructing the initial equivalent transformation relationship only if both the physical constraint tolerance verification and the dynamic response consistency verification are passed.

[0025] Subsequently, a correlation analysis was conducted on the first braking distance and the second braking distance, and the mass ratio was defined as the ratio of the total load mass of the escalator under full load condition to the total load mass under empty load condition. This is based on the fundamental physical principle of the balance between inertial force and friction during the braking process.

[0026] The mass ratio conversion factor is obtained by dividing the ratio of the second braking distance to the first braking distance by the mass ratio.

[0027] However, in order to improve the universality and robustness of the initial equivalent conversion relationship, it is necessary to use multiple sets of data to calibrate the mass ratio conversion factor: select multiple sets of effective no-load and full-load braking distance data of the same model but different machines, or the same machine under different test cycles, calculate the mass ratio conversion factor corresponding to each set, and statistically analyze the standard deviation of multiple sets of mass ratio conversion factors.

[0028] If the standard deviation is less than or equal to the preset fluctuation threshold, which can be set according to engineering experience, for example 0.05, it indicates that the data consistency is good. The multiple quality ratio conversion factors are sorted directly according to the numerical order, and the median of the sequence is selected as the conversion factor marked by the initial equivalent conversion relationship to resist the influence of possible slight outliers.

[0029] Conversely, if the standard deviation is greater than the preset fluctuation threshold, it indicates that the data dispersion is large and there may be outlier tests. In this case, box plots or the three-standard-deviation principle should be used to identify and remove outliers that significantly deviate from the cluster. Then, the arithmetic mean of the quality ratio conversion factor should be recalculated using the remaining valid data as the final conversion factor for the initial equivalent conversion relationship. This establishes the initial equivalent conversion relationship with the quality ratio as the conversion factor.

[0030] If the verification fails, the braking test for the corresponding state must be re-executed until valid data that meets the dual verification requirements is obtained, thus forming a closed loop for data quality control.

[0031] This invention establishes a dual verification mechanism, ensuring that the initial equivalent conversion relationship between the no-load braking distance and the full-load braking distance is established only when the physical constraint tolerance judgment is consistent with the dynamic response judgment. This ensures that the dataset involved in the initial conversion relationship construction is authentic and reliable, thereby improving the accuracy of the conversion relationship from the source.

[0032] The initial equivalent transformation relationship is based solely on the mass ratio and fails to reflect the nonlinear changes in the internal frictional characteristics of the braking system with load. To improve prediction accuracy, it is necessary to delve deeper into the braking system, quantify the load-sensitivity characteristics of key components, and correct the initial equivalent transformation relationship accordingly.

[0033] Based on this, S2. Identify the key components involved in the dissipation of braking energy in the escalator, analyze the equivalent friction coefficients of the key components under no-load and full-load conditions, and generate a correction factor based on the difference in equivalent friction coefficients under no-load and full-load conditions to correct the initial equivalent conversion relationship and obtain the corrected equivalent conversion relationship.

[0034] Since the braking process of an escalator is essentially a process in which kinetic energy is converted into heat energy and dissipated through friction between various components of the braking system, the key components involved in the braking energy dissipation in the overall structure of the escalator can be obtained first. These key components include at least the brake, the step chain, and the guide rail.

[0035] Based on the principle of energy conservation, the total kinetic energy consumed during braking is equal to the sum of the frictional dissipation energy of each key component. The total kinetic energy consumed during the braking process can be decomposed into the frictional dissipation energy term borne by each key component. Using the equivalent friction coefficient corresponding to each key component as the parameter to be solved, a total frictional torque equation containing the frictional dissipation energy term of all key components is established.

[0036] Taking the aforementioned set of key components, including the brake, ladder chain, and guide rail, as an example, the corresponding equation for the total frictional torque is as follows: .

[0037] in For total load mass, It is the acceleration due to gravity. These are the equivalent friction coefficients for the brake, ladder chain, and guide rail, respectively. These are constant dimensionless structural parameters reflecting the force relationship between the brake and the step chain. They are standard technical parameters provided by escalator manufacturers and can convert the total load weight into equivalent normal force acting on the brake and step chain. The angle of inclination of the escalator. The term represents the component of the total load weight perpendicular to the guide rail.

[0038] The left side of the equation represents the total kinetic energy possessed by the escalator at the moment of braking initiation.

[0039] The right-hand side of the equation represents the total work consumed by friction of all key components during braking, which can be decomposed into the brake friction dissipation energy term. Cascade chain friction dissipation energy term and the energy dissipation due to friction of the guide rail .

[0040] It should be noted that this decomposition does not refer to the independent and sequential energy consumption of each key component, but rather describes the parallel and superimposed relationship of their work done simultaneously within the same braking process and braking distance. In actual braking, all key components generate friction simultaneously, collectively causing the escalator to decelerate. This equation assumes that the frictional force of each key component is constant or has a constant average effect throughout the braking process, and that the braking distance is the same. Therefore, the total work is the sum of the work done by the frictional forces of each key component. Furthermore, since the frictional force of each key component is proportional to the total load mass, the right-hand side of the equation can be factored out to present a compact form.

[0041] The entire equation is based on the principle of energy conservation. The frictional energy consumption of each key component during braking is physically equivalent and lumped by introducing equivalent friction coefficients and structural parameters, thereby transforming the complex multibody friction problem into a solvable mathematical equation.

[0042] Please see Figure 3 As shown, the first braking distance and the total unloaded load mass, and the second braking distance and the total fully loaded load mass are substituted into the total friction torque equation, respectively, to obtain the equivalent friction coefficients of each key component under unloaded and fully loaded conditions. The specific process is as follows: Based on the overall deviation between the predicted braking distance calculated from the total friction torque equation using the current equivalent friction coefficient and the measured braking distance under the corresponding conditions, a target error function is constructed. The form of the target error function can refer to the root mean square error function. The smaller the function value, the more the current equivalent friction coefficient matches the measured data.

[0043] To improve inversion efficiency and avoid getting trapped in local optima, reasonable initial guess values ​​need to be set for each equivalent friction coefficient. Based on the structural layout of the escalator, all mechanical contact interfaces that participate in kinetic energy dissipation during braking are identified, and each key component is mapped to one or more mechanical contact interfaces.

[0044] By consulting mechanical design manuals, the typical friction coefficient range of the materials involved in each mechanical contact interface is obtained. The median value of this range is taken as the reference friction coefficient of the corresponding mechanical contact interface. When a key component corresponds to only one mechanical contact interface, the reference friction coefficient of the mapped mechanical contact interface is directly used as the initial guess value of the equivalent friction coefficient of the key component.

[0045] When a critical component corresponds to multiple mechanical contact interfaces, the multiple mechanical contact interfaces are equivalent to a single aggregate interface. The reference friction coefficients are weighted and averaged based on the equivalent action radius of each mechanical contact interface, and the final weighted average value is used as the initial guess value of the equivalent friction coefficient of the critical component.

[0046] Starting from the initial guess value, for both no-load and full-load conditions, the equivalent friction coefficient of each key component is iteratively updated to bring the value of the target error function to within the preset tolerance range.

[0047] It should be noted that the iterative update method can be gradient descent, quasi-Newton method, etc., which is determined by the actual application, and this invention does not impose any special restrictions.

[0048] During the iteration process, multiple sets of candidate equivalent friction coefficients that make the target error function converge are recorded, and the set of equivalent friction coefficients that minimizes the global target error function is selected as the final inversion result output.

[0049] The ratio of the equivalent friction coefficient of each key component under full load and no-load conditions is taken as the friction change rate.

[0050] However, the influence of each key component in the braking energy transmission path varies. It is necessary to determine the topological order of each key component in the energy transmission path from the drive system to the actuator. The topological structure is usually brake-drive transmission component-step chain-guide rail. The key components are assigned weights according to this topological order, following the principle that the earlier the component is in the topological order, the greater the weight. This principle is based on the premise that the entire braking system of the escalator is regarded as a series energy dissipation chain. The key component located at the front of the topological order has changes in its friction characteristics that not only affect its own energy consumption, but also cascade and affect the energy state available to all subsequent components. Therefore, its weight should be greater.

[0051] To this end, this invention provides a specific example of assigning weights to key components, defining a weight decay mechanism based on topological position, setting the weight value of the first key component in the topological order to 1, then the key component in the topological order is located at the [missing value]. The weight values ​​of each key component can be respectively as follows: , As a preset attenuation factor, It can be simulated or experimentally calibrated according to the energy transfer efficiency of different escalator models. The value is usually between 0.7 and 0.9, and it is used to control the attenuation rate of energy or weight along the transmission path.

[0052] The friction change rate of each key component is weighted and multiplied, and the result of the weighted multiplication is squared to obtain the correction factor, which is the total number of key components.

[0053] The correction factor Conversion factor with quality ratio By coupling, a corrected equivalent transformation relation is generated, which can be expressed as the following formula: .

[0054] in, The braking distance and total load weight under full load conditions. The braking distance and total load weight are under no-load conditions.

[0055] It should be noted that this formula is a mathematical expression of the equivalent transformation relationship derived step by step and finally established in steps S1 and S2 above. The meaning, acquisition process and function of each parameter in the formula have been explained in the preceding content. The purpose of presenting it here is to clearly show the final structure of the equivalent transformation relationship after correction, so as to facilitate understanding and application. The specific derivation details and physical principles will not be repeated.

[0056] This invention identifies key components and inverts their equivalent friction coefficients under no-load and full-load conditions. Based on the difference in equivalent friction coefficients between the two conditions, a correction factor is generated to quantify and compensate for the nonlinear load effect of friction in the escalator braking system, thereby correcting the initial equivalent conversion relationship and effectively improving the prediction accuracy and reliability of the full-load braking distance.

[0057] To ensure the reliability of the corrected equivalent transformation relationship and its applicability to the target equipment in engineering applications, and to avoid prediction biases that may result from directly extrapolating the equivalent transformation relationship established based on specific samples to similar equipment, this invention introduces a verification step for the applicability of the corrected mapping relationship before performing an unloaded braking test on the target escalator to predict its full-load braking performance: First, at least one reference escalator with the same model, manufacturing batch, and service life as the target escalator is selected as a verification sample.

[0058] Secondly, no-load and full-load braking tests were performed on the reference escalator to obtain its measured braking distance under no-load and full-load conditions.

[0059] Then, the unloaded measured braking distance of the reference escalator is input into the formula presented by the above-corrected equivalent transformation relationship to calculate its full-load predicted braking distance and compare it with the actual full-load measured braking distance of the reference escalator to evaluate whether the prediction error is within the preset engineering accuracy acceptance range, such as ±10% which is acceptable in engineering. This threshold example is set based on the industry consensus on the general accuracy of indirect prediction methods.

[0060] If the prediction error meets the accuracy requirements, the corrected mapping relationship is deemed applicable to the same type of escalator and can be used for predicting the full-load braking distance of the target escalator. Otherwise, data from multiple reference escalators needs to be collected again to optimize the mapping relationship.

[0061] Based on the fact that the prediction error meets the accuracy requirements, S3. Obtain the no-load braking distance of the target escalator in the current state, predict the full-load braking distance of the target escalator based on the corrected equivalent transformation relationship, and conduct a safety compliance evaluation based on the prediction results.

[0062] The specific process of the safety compliance evaluation is as follows: collect service status information of the target escalator from its maintenance file, including the cumulative operating cycle, the number of brake actions, and the most recent maintenance record.

[0063] Based on the service status information, determine whether the current service status of the target escalator meets at least one of the following key braking performance degradation characteristics: I. The cumulative operating cycle exceeds the critical braking aging cycle specified for the target escalator.

[0064] II. The number of braking cycles exceeds the design durability cycle of the escalator's embedded brake.

[0065] III. The most recent maintenance record is more than a reasonable maintenance interval has passed since then, and no critical braking components were replaced during that period.

[0066] It should be noted that the critical period for brake aging is set based on the overhaul cycle recommended by the escalator manufacturer, the number of design durability cycles is the mechanical life cycle specified in the brake product manual, and the reasonable maintenance interval is determined based on the maintenance cycle recommended in the technical maintenance manual provided by the equipment manufacturer, combined with industry-recognized maintenance procedures.

[0067] If at least two of the following conditions are met, the braking performance of the target escalator is determined to be severely degraded.

[0068] If only one of the performance criteria is met, the braking performance is judged to be moderately diminished.

[0069] If any one of the performance criteria is not met, the braking performance is determined to be either no degradation or slight degradation.

[0070] Based on the graded assessment results of the braking performance degradation of the target escalator, the maximum allowable value of the full-load braking distance specified in the safety standard of the target escalator is adaptively adjusted. Specifically, the preset safety factor mapping relationship is queried. If the braking performance is severely degraded, the adjustment factor is the preset minimum safety factor.

[0071] If the attenuation is moderate, the adjustment coefficient is determined by linear interpolation within a preset adjustment coefficient range based on the magnitude of the over-limit parameter in the corresponding key attenuation performance. Taking the cumulative operating cycle exceeding the critical braking aging period of the target escalator as an example, the number of days of overdue operation is taken as the over-limit parameter, and the ratio of it to the critical braking aging period of the target escalator is taken as the over-limit magnitude. The adjustment coefficient obtained after linear interpolation is obtained by subtracting the product of the over-limit magnitude and the range of the adjustment coefficient range from the preset maximum safety factor.

[0072] The other two key attenuation indicators correspond to the following over-limit parameters: the number of braking cycles exceeding the design durability cycle and the number of days exceeding the reasonable maintenance cycle. The specific process of determining the adjustment coefficient by linear interpolation is the same as the specific logic of the above example of the cumulative operating cycle exceeding the critical cycle of braking aging of the target escalator, and will not be elaborated here.

[0073] If there is no attenuation or slight attenuation, the adjustment factor is the preset maximum safety factor.

[0074] The basis for the above-mentioned grading assessment of braking performance degradation and corresponding adaptive adjustments is that: escalators simultaneously meeting at least two key degradation characteristics indicate that the deterioration of their braking system has multi-dimensional and systemic features. For example, the coexistence of overdue operation and excessive braking actions means that components are simultaneously experiencing material fatigue and excessive mechanical wear; overdue maintenance coupled with any other manifestation indicates that performance degradation continues to accumulate without intervention. The superposition of multiple factors significantly increases the risk of systemic failure, therefore, the most stringent safety limit tightening strategy must be adopted.

[0075] The escalator only meets the single-item degradation performance standard, indicating the existence of a clear and isolated risk factor. Although this factor will cause negative performance changes, the state of the rest of the system is still acceptable, and the overall degradation is in a controllable and gradual stage. Therefore, appropriate adjustments to the safety limits are needed based on the specific degree to which this risk factor exceeds the limits.

[0076] The escalator did not meet any critical attenuation performance criteria, indicating that its operating time, number of actuations, and maintenance records are all within design or specification benchmarks. The braking system has no significant abnormal risks, and its performance baseline is stable or only exhibits slight natural aging. Therefore, it can be directly evaluated using standard safety margins without the need for preventative limit tightening.

[0077] As an example, the preset minimum safety factor is 0.7, the maximum safety factor is 1.0, and the adjustment factor range is [0.7, 1.0]. This setting is based on maintaining a standard safety margin under no-attenuation or mild-attenuation conditions. Under severe-attenuation conditions, based on the industry's conservative estimate of performance degradation under extreme wear conditions of critical components, the safety margin is further tightened by 30%. Those skilled in the art can adjust this principle based on specific safety specifications.

[0078] The dynamic safety limit is obtained by multiplying the adjustment coefficient by the original maximum allowable braking distance under full load.

[0079] If the predicted full-load braking distance is less than or equal to the dynamic safety limit, it is determined that the target escalator meets the dynamic safety standard under its current service condition; otherwise, a maintenance warning or a command to prohibit full-load operation is issued.

[0080] This invention incorporates the service status information of the target escalator into the safety compliance evaluation process of the full-load braking distance, realizing the individualization and dynamism of the safety evaluation standard, enabling forward warning of performance degradation, and effectively avoiding missed or misjudgments.

[0081] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, and all such modifications and additions should fall within the protection scope of the present invention.

Claims

1. A method for evaluating the braking performance of an escalator under full load, characterized in that, include: Based on braking test data of the same model of escalator under no-load and full-load conditions, an initial equivalent conversion relationship between no-load braking distance and full-load braking distance is established. Key components involved in braking energy dissipation in escalators are identified, and the equivalent friction coefficients of these key components under no-load and full-load conditions are analyzed. Based on the difference in equivalent friction coefficients under no-load and full-load conditions, a correction factor is generated to correct the initial equivalent transformation relationship, resulting in the corrected equivalent transformation relationship. Obtain the no-load braking distance of the target escalator in the current state, predict the full-load braking distance of the target escalator based on the corrected equivalent transformation relationship, and conduct a safety compliance evaluation based on the prediction results; Synchronous comparative tests were conducted, collecting data on the changes in the first braking distance and first braking deceleration during emergency braking under no-load conditions and the second braking distance and second braking deceleration during emergency braking under full load conditions for the same model of escalator in a laboratory environment. The average deceleration of the first and second braking actions was calculated. Based on kinematic relationships, the numerical relationships between the first and second braking distances and their average decelerations were verified to ensure compliance with physical constraint tolerances. The trend characteristics of the first and second braking deceleration change sequences were compared to verify the consistency of the dynamic responses during emergency braking under no-load and full load conditions. If and only if the physical constraint tolerance verification is consistent with the dynamic response verification, a correlation analysis was performed on the first and second braking distances to establish an initial equivalent conversion relationship using the mass ratio as a conversion factor. Otherwise, the braking tests under the corresponding conditions were re-executed until the requirements were met. The mass ratio is defined as the ratio of the total load mass of the escalator under full load conditions to the total load mass under no-load conditions; the mass ratio conversion factor is obtained by dividing the ratio of the second braking distance to the first braking distance by the mass ratio. Select multiple sets of no-load and full-load braking distance data of the same model but different machines or the same machine under different test cycles, calculate the corresponding mass ratio conversion factor for each set, and statistically analyze the standard deviation of multiple sets of mass ratio conversion factors. If the standard deviation is less than or equal to the preset fluctuation threshold, the multiple quality ratio conversion factors are sorted in numerical order, and the median of the sequence is selected as the conversion factor marked in the initial equivalent conversion relationship; otherwise, if the standard deviation is greater than the preset fluctuation threshold, outliers in the sequence are identified and removed, and the arithmetic mean of the quality ratio conversion factors is recalculated using the remaining valid data as the conversion factor marked in the initial equivalent conversion relationship.

2. The method for evaluating the braking performance of an escalator under full load according to claim 1, characterized in that, The equivalent friction coefficients of the key components analyzed under no-load and full-load conditions include: Obtain the set of key components involved in braking energy dissipation in the overall structure of the escalator, wherein the key components include at least the brake, the step chain, and the guide rail; Based on the principle of energy conservation, the total kinetic energy consumed during the braking process of the whole machine is decomposed into the frictional dissipation energy term borne by each key component; Using the equivalent friction coefficients of each key component as the parameters to be solved, a total friction torque equation containing the frictional dissipation energy of all key components is established. Substituting the first braking distance and the total unloaded load mass, and the second braking distance and the total fully loaded load mass, into the total friction torque equation, respectively, the equivalent friction coefficients of each key component under unloaded and fully loaded conditions are obtained by inversion.

3. The method for evaluating the braking performance of an escalator under full load according to claim 2, characterized in that, The inversion process of the equivalent friction coefficient of each key component under no-load and full-load conditions includes: Based on the overall deviation between the predicted braking distance calculated from the total friction torque equation using the current equivalent friction coefficient and the measured braking distance under the corresponding working conditions, a target error function is constructed. Based on the structural layout of the escalator, identify all mechanical contact interfaces that participate in kinetic energy dissipation during braking, and map each key component to one or more mechanical contact interfaces. Based on the typical friction coefficient range of the materials involved in the mechanical contact interface, an initial guess value is set for the equivalent friction coefficient of each key component; Starting from the initial guess value, for both no-load and full-load conditions, the equivalent friction coefficient of each key component is iteratively updated to bring the target error function to a preset tolerance range. During the iteration process, multiple sets of candidate equivalent friction coefficients that make the target error function converge are recorded, and the set of equivalent friction coefficients with the smallest target error function is selected as the final inversion result output.

4. The method for evaluating the braking performance of an escalator under full load according to claim 3, characterized in that, The process of setting initial guesses for the equivalent friction coefficient of each key component includes: The median value of the typical friction coefficient range of the materials involved in the mechanical contact interface is used as the reference friction coefficient of the mechanical contact interface. If a critical component corresponds to only one mechanical contact interface, then the reference friction coefficient of the mapped mechanical contact interface is used as the initial guess value. If there are multiple mechanical contact interfaces, they are equivalent to a single aggregate interface, with the initial guess value being the weighted average of the reference friction coefficients of the interfaces involved, based on a specified radius of action.

5. The method for evaluating the braking performance of an escalator under full load according to claim 1, characterized in that, Correcting the initial equivalent transformation relationship includes: The ratio of the equivalent friction coefficient of each key component under full load and no-load conditions is taken as the friction change rate. Based on the direction of braking energy transmission, determine the topological order of each key component in the energy transmission path, and assign weights to each key component according to this topological order. The friction change rate of each key component is weighted and multiplied, and the square root of the weighted multiplication result is taken to obtain the correction factor. The correction factor is coupled with the mass ratio conversion factor to generate the corrected equivalent conversion relationship.

6. The method for evaluating the braking performance of an escalator under full load according to claim 1, characterized in that, The safety compliance assessment includes: The target escalator's service status information includes cumulative operating cycles, number of brake actions, and the most recent maintenance record. Based on the service status information, the degree of braking performance degradation of the target escalator is assessed in a graded manner, and the maximum allowable value of the full-load braking distance specified in the safety standard of the target escalator is adaptively adjusted accordingly to generate dynamic safety limits; If the predicted full-load braking distance is less than or equal to the dynamic safety limit, it is determined that the target escalator meets the dynamic safety standard under its current service condition; otherwise, a maintenance warning or a command to prohibit full-load operation is issued.

7. The method for evaluating the braking performance of an escalator under full load according to claim 6, characterized in that, The graded assessment of the degree of braking performance degradation of the target escalator includes: Determine whether the target escalator currently meets at least one of the following key braking performance degradation characteristics: I. The cumulative operating cycle exceeds the critical braking aging period specified for the target escalator; II. The number of braking cycles of the brake exceeds the design durability cycle of the target escalator's embedded brake; III. The most recent maintenance record is more than the reasonable maintenance interval, and no critical braking components were replaced during that period; If at least two of the following conditions are met, the braking performance of the target escalator is determined to be severely degraded. If only one of the performance criteria is met, the braking performance is judged to be moderately diminished. If any one of the performance criteria is not met, the braking performance is determined to be either no degradation or slight degradation.

8. The method for evaluating the braking performance of an escalator under full load according to claim 7, characterized in that, The adaptive adjustment process includes: Based on the braking performance attenuation level, query the preset safety factor mapping relationship to obtain the corresponding adjustment factor; The safety factor mapping relationship is specified at least as follows: If braking performance is severely degraded, the adjustment factor is the preset minimum safety factor; If it is moderate attenuation, the adjustment coefficient is determined by linear interpolation within the preset adjustment coefficient range based on the magnitude of the out-of-limit parameter in the corresponding key attenuation performance. If there is no attenuation or slight attenuation, the adjustment factor is the preset maximum safety factor; The dynamic safety limit is obtained by multiplying the adjustment coefficient by the original maximum allowable braking distance under full load.

Images