Multi-parameter measurement method for elevator based on MEMS three-axis acceleration sensor

Abstract

The application discloses a kind of elevator multi-parameter measurement methods based on MEMS three-axis acceleration sensor, and relates to elevator or escalator multi-parameter comprehensive detection technical field.In the elevator multi-parameter measurement methods based on MEMS three-axis acceleration sensor, through the comprehensive detection analysis of vertical elevator brake performance parameters, car three-axis vibration comfort, running speed, running acceleration, start-stop acceleration, car levelness, guide rail installation plumbness, mechanical component abnormal vibration frequency and other parameters by MEMS three-axis acceleration sensor, the measurement accuracy can be effectively improved, and the real-time of field calculation;Through the comprehensive detection analysis of brake performance parameters, carrying device vibration comfort, handrail belt vibration comfort, running speed, escalator inclination angle, main mechanical component abnormal vibration frequency and other parameters of escalator or moving sidewalk by MEMS three-axis acceleration sensor, the measurement accuracy can be effectively improved, and the real-time of field calculation.

Description

Technical Field

[0001] This invention relates to the field of multi-parameter integrated detection technology for elevators or escalators, and in particular to a multi-parameter measurement method for elevators based on a MEMS triaxial accelerometer. Background Technology

[0002] Elevators, as a type of vertical transportation tool, play an important role in people's production and daily life. At the same time, as a type of electromechanical special equipment, their safety performance has also received widespread attention.

[0003] Based on their structure, elevators can be divided into vertical elevators, inclined elevators, escalators, and moving walkways. Various testing methods, tools, and instruments are required for all types of elevators during installation, maintenance, inspection, spot checks, and accident investigations.

[0004] Various sensors are widely used in testing instruments to measure the physical parameters of elevator mechanical and electrical components on-site. Accelerometers have been extensively applied in elevator testing, and different acceleration data analysis methods can be used to measure various elevator parameters. For example: the fluctuation characteristics of acceleration data around the average value can be used to analyze elevator vibration comfort; numerical integration of acceleration can measure parameters such as elevator speed and travel distance; frequency domain analysis of acceleration signals can reveal the main vibration frequencies, enabling fault tracing of failed components; and tilt angle data can be obtained by analyzing the projection components of gravitational acceleration on the three data axes of the sensor.

[0005] Existing elevator testing instruments based on triaxial accelerometers typically use traditional analog output accelerometers, resulting in large overall size, limited functionality, and low integration, making it difficult to meet the multi-parameter testing requirements of elevators on-site. For example, the widely used EVA625 elevator comprehensive performance tester is bulky and has various applications in elevators and escalators, but test results cannot be obtained instantly on-site. Data files need to be copied to a USB drive and then manually analyzed on a computer. Furthermore, the EVA625 tester's data files are closed to the user, making it inconvenient for custom data analysis and secondary plotting. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-parameter measurement method for elevators based on a MEMS triaxial accelerometer. This method can be comprehensively applied to various detection scenarios such as elevator or escalator motion parameter measurement, vibration comfort assessment, braking parameter measurement, mechanical component failure analysis, and tilt angle measurement, thereby fully leveraging the application effectiveness of MEMS accelerometers.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for measuring multiple parameters of an elevator based on a MEMS triaxial accelerometer includes the following steps:

[0009] A triaxial accelerometer is used to measure various parameters of a vertical elevator.

[0010] The measuring device has three conical feet at the bottom of its module. When measuring vibration comfort, the measuring device is placed on the car floor, with the X-axis or Y-axis perpendicular to the elevator door. The operator stands inside the car, holding a data terminal, and operates the elevator from the bottom floor to the top floor or from the top floor to the bottom floor. The three-axis vibration acceleration signals are recorded during the elevator operation. The data terminal analyzes the data to obtain vibration characteristic parameters, so as to quantitatively evaluate the car vibration and ride quality.

[0011] During the braking performance test, the measuring device module is placed on the car floor. During the data acquisition process, personnel leave the elevator car. The test ends after the braking is completed and the elevator is leveled. The data terminal automatically performs data analysis.

[0012] When testing the vibration of the ferromagnetic components of the elevator host, there is no need to use support legs. The magnet inside the measuring device is directly attached to the metal surface of the component under test, and the vibration condition is tested; or, the sensor is attached to the surface of the object under test by installing a circular magnetic base at the bottom of the module of the measuring device.

[0013] A triaxial accelerometer is used to measure various parameters of escalators or moving walkways:

[0014] Place the measuring device on the step, adjust the position of the support legs so that all three support legs simultaneously engage with the grooves on the surface of the step. The operator stands on a step near the step where the measuring device module is located, presses the switch button to establish communication with the data terminal, and operates the escalator after the test begins. During operation, the vibration of the steps is tested to achieve the upward vibration comfort test or downward vibration comfort test of the escalator steps, or to test the parameters of the escalator's average braking deceleration and braking distance.

[0015] Similarly, when testing the vibration comfort of moving walkway treads, the measuring device should be placed at both the inclined and horizontal sections.

[0016] When testing the vibration of the handrail belt of an escalator or moving walkway, the operator stands on the escalator step or moving walkway tread, holds the vibration measuring device, removes the three support feet at the bottom of the module, and makes the X direction of the measuring device point to the direction of elevator operation. The operator then operates the escalator or moving walkway and tests the vibration of the handrail belt during operation.

[0017] During the test, the vibration of the two handrail belts in both the upward and downward directions was measured, and the running speed of the handrail belts was measured over a short period of time.

[0018] Among them, when analyzing the vibration comfort of a straight elevator, due to the unevenness of the car floor and the assembly error of the module circuit board, the horizontal tilt angle of the module needs to be compensated and the DC component of gravity acceleration needs to be deducted before the vibration comfort calculation, so as to obtain an orthogonal triaxial vibration acceleration data sequence.

[0019] The angles between the X-axis, Y-axis, and Z-axis and the horizontal plane are calculated based on the projected components of the gravitational acceleration on the three data axes when the module is stationary. The calculation principle is as follows:

[0020]

[0021] In the formula: α is the angle between the module's X-axis and the horizontal plane (rad), β is the angle between the module's Y-axis and the horizontal plane (rad), γ is the angle between the module's Z-axis and the horizontal plane (rad), and a x The projection component of gravitational acceleration on the X-axis when the module is stationary (m / s²) 2 a y The projection component of gravitational acceleration on the Y-axis when the module is stationary (m / s²) 2 a z The projection component of gravitational acceleration on the Z-axis when the module is stationary (m / s²) 2 .

[0022] Specifically, during the calculation, a x a y and a z The average acceleration over 1 second when the module is stationary is taken; the original acceleration is corrected according to the projection relationship of gravitational acceleration on the three measurement axes to ensure that the acceleration data used in subsequent analysis are absolute horizontal and vertical data. The correction method is as follows:

[0023] A x =a x -A z sinα, A y =a y -A z sinβ;

[0024] In the formula: A z The corrected Z-axis acceleration in m / s² 2 A x The corrected X-axis acceleration in m / s² 2 A y The corrected Y-axis acceleration in m / s² 2 .

[0025] Furthermore, due to the influence of human physiological structure, different vibration frequencies will lead to differences in passengers' perception of vibration amplitude. In order to make the vibration test results more consistent with the human experience of elevator comfort, it is necessary to perform frequency weighting on vibration acceleration.

[0026] Frequency weighting includes four filtering processes: high-pass and low-pass second-order Butterworth filtering, av transform filtering, and high-pass filtering, to obtain the time-domain curves of the three-axis acceleration after frequency weighting. The peak-to-peak value sequence of the three axes is obtained through curve analysis. The peak-to-peak values ​​of the vibration are sorted, and the maximum peak-to-peak value and A95 peak-to-peak value are solved to quantitatively evaluate the vibration comfort.

[0027] In the escalator vibration comfort analysis, the total frequency weighting function is the product of four filter functions: high-pass and low-pass second-order Butterworth filter, av transform filter, and higher-order filter; the Z-transform transfer function of each filter process is:

[0028]

[0029] Where H(z) is the Z-transform output value, a is the numerator vector of the digital filter: a = [1, a2, a3], b is the denominator vector of the digital filter: b = [b1, b2, b3], and the Z vector is: Z = [1, z -1 , z -2 ] T .

[0030] Specifically, different frequency weighting methods are used for different vibration-sensing parts, vibration directions, and human postures, corresponding to different filter parameters;

[0031] Standing horizontal whole-body vibration using frequency weighting W d Standing vertical whole-body vibration using frequency weighting W k The hand-transmitted vibration uses frequency-weighted W h Different filter vectors a and b are used in different filtering processes under different frequency weighting methods. The recursive calculation formula for digital filtering of the m-th acceleration data is as follows:

[0032] y(m)=b1x(m)+b2x(m-1)+b3x(m-2)-a2y(m-1)-a3y(m-2);

[0033] In the formula, x is the data sequence before filtering, y is the data sequence after filtering, and m is the number of the filtered data in the sequence.

[0034] Furthermore, for step vibration, the RMS value of the triaxial frequency-weighted data needs to be calculated separately; for handrail vibration, the downward X-axis value of the handrail needs to be calculated. h The RMS value of the directional frequency-weighted data, with a time constant of 1 second, is calculated using the following formula for the Nth RMS data:

[0035]

[0036] In the formula, n is the number of acceleration data within a 1s time constant, and a is the acceleration value after frequency weighting;

[0037] For stepped vibration, the overall vibration energy is evaluated using a triaxial RMS vector sum:

[0038]

[0039] In the formula, a xyz Let a be the sum of vibration vectors. x a is the RMS value of the X-axis vibration. y a is the RMS value of the Y-axis vibration. z This represents the RMS value of the Z-axis vibration.

[0040] When analyzing the acceleration, deceleration, speed, and displacement of elevators or escalators during start-stop, before performing the elevator motion characteristic analysis, the original acceleration data of the sensor's Z-axis is first subjected to a second-order Butterworth low-pass filter with a filter cutoff frequency of 10Hz.

[0041] Acceleration and deceleration reflect the pressure exerted on the human body by the elevator car floor. Quantifying the maximum acceleration and maximum deceleration can be used to evaluate whether the elevator's operation control settings are reasonable in relation to passenger quality results. The maximum acceleration is the maximum value of the acceleration signal when the elevator starts, and the maximum deceleration is the maximum absolute value of the deceleration signal during the elevator's braking process. The A95 acceleration value is statistically calculated within the range of 5% to 95% of the maximum speed during acceleration, and 95% of the acceleration data within this range are less than this value. The A95 deceleration value is statistically calculated within the range of 95% to 5% of the maximum speed during deceleration, and 95% of the absolute values ​​of the deceleration data within this range are less than this value.

[0042] The maximum speed is the maximum absolute value of the speed throughout the entire elevator's operating cycle; the statistically calculated limit range of the V95 speed is from the maximum speed V during the acceleration phase. max1 95% corresponds to the maximum speed V during the deceleration phase from the 1 second following the data point. max2 95% corresponds to the first second of the time point where the data is located. Within this calculation limit, 95% of the velocity values ​​are less than the V95 velocity.

[0043] Specifically, the composite 1 / 3 Simpson numerical integration method is used to integrate the Z-axis acceleration after Butterworth filtering to calculate the velocity sequence. The numerical integral velocity calculation formula at time t is:

[0044]

[0045] In the formula, v(t) is the velocity at time t, in m / s, h is the time step of the acceleration data sequence, and a(0) is the initial acceleration, in m / s. 2a(t) is the acceleration at time t in m / s². 2 n is the number of data points in the integration interval;

[0046] The composite 1 / 3 Simpson method is used to numerically integrate the velocity data to calculate the elevator's displacement sequence, which yields information such as the lifting height. The formula for calculating the numerically integrated displacement at time t is:

[0047]

[0048] Furthermore, when analyzing the braking parameters of straight elevators or escalators, in order to reflect the actual running acceleration of the steps on the Z-axis, the gravitational acceleration bias needs to be subtracted. During the calculation, the average value of the Z-axis acceleration data within 3 seconds after the braking ends and before the data acquisition stops is taken as the gravitational acceleration bias.

[0049] The velocity and displacement data sequences in the horizontal and vertical directions are obtained using numerical integration methods. Acceleration, velocity, and displacement curves along the X and Z axes during the braking process are plotted. The characteristic values ​​of these curves are analyzed to calculate the braking parameters of the escalator in both the horizontal and vertical directions. During the braking process, the actual running direction of the escalator steps is downward at an incline. The sum of the velocity vectors in the X and Z directions represents the actual running velocity of the steps, and the sum of the displacement vectors represents the step displacement. By comprehensively analyzing the velocity and displacement vector sum curves, the average braking deceleration and total stopping distance can be calculated.

[0050] Compared with existing technologies, the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer described in this invention has the following advantages:

[0051] The multi-parameter measurement method for elevators based on MEMS triaxial accelerometers provided by this invention effectively improves measurement accuracy and real-time on-site calculation by comprehensively detecting and analyzing parameters such as vertical elevator braking performance parameters, car triaxial vibration comfort, running speed, running acceleration, start-stop acceleration and deceleration, car levelness, guide rail installation plumbness, and abnormal vibration frequency of mechanical components through MEMS triaxial accelerometers. Similarly, the comprehensive detection and analysis of parameters such as escalator or moving walkway braking performance parameters, carrier vibration comfort, handrail vibration comfort, running speed, escalator tilt angle, and abnormal vibration frequency of major mechanical components through MEMS triaxial accelerometers effectively improves measurement accuracy and real-time on-site calculation. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the first measurement state structure of the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer provided in an embodiment of the present invention.

[0053] Figure 2This is a schematic diagram of the second measurement state structure of the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer provided in an embodiment of the present invention.

[0054] Figure 3 This is a schematic diagram of the third measurement state structure of the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer provided in an embodiment of the present invention.

[0055] Figure 4 This is a schematic diagram of the fourth measurement state structure of the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer provided in an embodiment of the present invention.

[0056] Figure 5 This is a schematic diagram of the fifth measurement state structure of the multi-parameter measurement method for elevators based on a MEMS triaxial accelerometer provided in an embodiment of the present invention. Detailed Implementation

[0057] For ease of understanding, the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer provided in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0058] This invention provides a method for measuring multiple parameters of an elevator based on a MEMS triaxial accelerometer, such as... Figures 1-5 As shown, it includes the following steps:

[0059] A triaxial accelerometer is used to measure various parameters of a vertical elevator.

[0060] The measuring device has three conical feet at the bottom of its module. When measuring vibration comfort, the measuring device is placed on the car floor, with the X-axis or Y-axis perpendicular to the elevator door. The operator stands inside the car, holding a data terminal, and operates the elevator from the bottom floor to the top floor or from the top floor to the bottom floor. The three-axis vibration acceleration signals are recorded during the elevator operation. The data terminal analyzes the data to obtain vibration characteristic parameters, so as to quantitatively evaluate the car vibration and ride quality.

[0061] During the braking performance test, the measuring device module is placed on the car floor. During the data acquisition process, personnel leave the elevator car. The test ends after the braking is completed and the elevator is leveled. The data terminal automatically performs data analysis.

[0062] When testing the vibration of the ferromagnetic components of the elevator host, there is no need to use support legs. The magnet inside the measuring device is directly attached to the metal surface of the component under test, and the vibration condition is tested; or, the sensor is attached to the surface of the object under test by installing a circular magnetic base at the bottom of the module of the measuring device.

[0063] A triaxial accelerometer is used to measure various parameters of escalators or moving walkways:

[0064] Place the measuring device on the step, adjust the position of the support legs so that all three support legs simultaneously engage with the grooves on the surface of the step. The operator stands on a step near the step where the measuring device module is located, presses the switch button to establish communication with the data terminal, and operates the escalator after the test begins. During operation, the vibration of the steps is tested to achieve the upward vibration comfort test or downward vibration comfort test of the escalator steps, or to test the parameters of the escalator's average braking deceleration and braking distance.

[0065] Similarly, when testing the vibration comfort of moving walkway treads, the measuring device should be placed at both the inclined and horizontal sections.

[0066] When testing the vibration of the handrail belt of an escalator or moving walkway, the operator stands on the escalator step or moving walkway tread, holds the vibration measuring device, removes the three support feet at the bottom of the module, and makes the X direction of the measuring device point to the direction of elevator operation. The operator then operates the escalator or moving walkway and tests the vibration of the handrail belt during operation.

[0067] During the test, the vibration of the two handrail belts in both the upward and downward directions was measured, and the running speed of the handrail belts was measured over a short period of time.

[0068] Compared with existing technologies, the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer described in this embodiment of the invention has the following advantages:

[0069] The multi-parameter measurement method for elevators based on MEMS triaxial accelerometers provided in this invention effectively improves measurement accuracy and real-time on-site calculation by comprehensively detecting and analyzing parameters such as vertical elevator braking performance parameters, car triaxial vibration comfort, running speed, running acceleration, start-stop acceleration and deceleration, car levelness, guide rail installation plumbness, and abnormal vibration frequency of mechanical components through MEMS triaxial accelerometers. Similarly, the comprehensive detection and analysis of parameters such as escalator or moving walkway braking performance parameters, carrier vibration comfort, handrail vibration comfort, running speed, escalator tilt angle, and abnormal vibration frequency of major mechanical components through MEMS triaxial accelerometers effectively improves measurement accuracy and real-time on-site calculation.

[0070] Among them, when analyzing the vibration comfort of a straight elevator, due to the unevenness of the car floor and the assembly error of the module circuit board, the horizontal tilt angle of the module needs to be compensated and the DC component of gravity acceleration needs to be deducted before the vibration comfort calculation, so as to obtain an orthogonal triaxial vibration acceleration data sequence.

[0071] The angles between the X-axis, Y-axis, and Z-axis and the horizontal plane are calculated based on the projected components of the gravitational acceleration on the three data axes when the module is stationary. The calculation principle is as follows:

[0072]

[0073] In the formula: α is the angle between the module's X-axis and the horizontal plane (rad), β is the angle between the module's Y-axis and the horizontal plane (rad), γ is the angle between the module's Z-axis and the horizontal plane (rad), and a x The projection component of gravitational acceleration on the X-axis when the module is stationary (m / s²) 2 a y The projection component of gravitational acceleration on the Y-axis when the module is stationary (m / s²) 2 a z The projection component of gravitational acceleration on the Z-axis when the module is stationary (m / s²) 2 .

[0074] Specifically, during the calculation, a x a y and a z The average acceleration over 1 second when the module is stationary is taken; the original acceleration is corrected according to the projection relationship of gravitational acceleration on the three measurement axes to ensure that the acceleration data used in subsequent analysis are absolute horizontal and vertical data. The correction method is as follows:

[0075] A x =a x -A z sinα, A y =a y -A z sinβ;

[0076] In the formula: A z The corrected Z-axis acceleration in m / s² 2 A x The corrected X-axis acceleration in m / s² 2 A y The corrected Y-axis acceleration in m / s² 2 .

[0077] Furthermore, due to the influence of human physiological structure, different vibration frequencies will lead to differences in passengers' perception of vibration amplitude. In order to make the vibration test results more consistent with the human experience of elevator comfort, it is necessary to perform frequency weighting on vibration acceleration.

[0078] Frequency weighting includes four filtering processes: high-pass and low-pass second-order Butterworth filtering, av transform filtering, and high-pass filtering, to obtain the time-domain curves of the three-axis acceleration after frequency weighting. The peak-to-peak value sequence of the three axes is obtained through curve analysis. The peak-to-peak values ​​of the vibration are sorted, and the maximum peak-to-peak value and A95 peak-to-peak value are solved to quantitatively evaluate the vibration comfort.

[0079] In the escalator vibration comfort analysis, the total frequency weighting function is the product of four filter functions: high-pass and low-pass second-order Butterworth filter, av transform filter, and higher-order filter; the Z-transform transfer function of each filter process is:

[0080]

[0081] Where H(z) is the Z-transform output value, a is the numerator vector of the digital filter: a = [1, a2, a3], b is the denominator vector of the digital filter: b = [b1, b2, b3], and the Z vector is: Z = [1, z -1 , z -2 ] T .

[0082] Specifically, different frequency weighting methods are used for different vibration-sensing parts, vibration directions, and human postures, corresponding to different filter parameters;

[0083] Standing horizontal whole-body vibration using frequency weighting W d Standing vertical whole-body vibration using frequency weighting W k The hand-transmitted vibration uses frequency-weighted W h Different filter vectors a and b are used in different filtering processes under different frequency weighting methods. The recursive calculation formula for digital filtering of the m-th acceleration data is as follows:

[0084] y(m)=b1x(m)+b2x(m-1)+b3x(m-2)-a2y(m-1)-a3y(m-2);

[0085] In the formula, x is the data sequence before filtering, y is the data sequence after filtering, and m is the number of the filtered data in the sequence.

[0086] Furthermore, for step vibration, the RMS value of the triaxial frequency-weighted data needs to be calculated separately; for handrail vibration, the downward X-axis value of the handrail needs to be calculated. h The RMS value of the directional frequency-weighted data, with a time constant of 1 second, is calculated using the following formula for the Nth RMS data:

[0087]

[0088] In the formula, n is the number of acceleration data within a 1s time constant, and a is the acceleration value after frequency weighting;

[0089] For stepped vibration, the overall vibration energy is evaluated using a triaxial RMS vector sum:

[0090]

[0091] In the formula, a xyzLet a be the sum of vibration vectors. x a is the RMS value of the X-axis vibration. y a is the RMS value of the Y-axis vibration. z This represents the RMS value of the Z-axis vibration.

[0092] When analyzing the acceleration, deceleration, speed, and displacement of elevators or escalators during start-stop, before performing the elevator motion characteristic analysis, the original acceleration data of the sensor's Z-axis is first subjected to a second-order Butterworth low-pass filter with a filter cutoff frequency of 10Hz.

[0093] Acceleration and deceleration reflect the pressure exerted on the human body by the elevator car floor. Quantifying the maximum acceleration and maximum deceleration can be used to evaluate whether the elevator's operation control settings are reasonable in relation to passenger quality results. The maximum acceleration is the maximum value of the acceleration signal when the elevator starts, and the maximum deceleration is the maximum absolute value of the deceleration signal during the elevator's braking process. The A95 acceleration value is statistically calculated within the range of 5% to 95% of the maximum speed during acceleration, and 95% of the acceleration data within this range are less than this value. The A95 deceleration value is statistically calculated within the range of 95% to 5% of the maximum speed during deceleration, and 95% of the absolute values ​​of the deceleration data within this range are less than this value.

[0094] The maximum speed is the maximum absolute value of the speed throughout the entire elevator's operating cycle; the statistically calculated limit range of the V95 speed is from the maximum speed V during the acceleration phase. max1 95% corresponds to the maximum speed V during the deceleration phase from the 1 second following the data point. max2 95% corresponds to the first second of the time point where the data is located. Within this calculation limit, 95% of the velocity values ​​are less than the V95 velocity.

[0095] Specifically, the composite 1 / 3 Simpson numerical integration method is used to integrate the Z-axis acceleration after Butterworth filtering to calculate the velocity sequence. The numerical integral velocity calculation formula at time t is:

[0096]

[0097] In the formula, v(t) is the velocity at time t, in m / s, h is the time step of the acceleration data sequence, and a(0) is the initial acceleration, in m / s. 2 a(t) is the acceleration at time t in m / s². 2 n is the number of data points in the integration interval;

[0098] The composite 1 / 3 Simpson method is used to numerically integrate the velocity data to calculate the elevator's displacement sequence, which yields information such as the lifting height. The formula for calculating the numerically integrated displacement at time t is:

[0099]

[0100] Furthermore, when analyzing the braking parameters of straight elevators or escalators, in order to reflect the actual running acceleration of the steps on the Z-axis, the gravitational acceleration bias needs to be subtracted. During the calculation, the average value of the Z-axis acceleration data within 3 seconds after the braking ends and before the data acquisition stops is taken as the gravitational acceleration bias.

[0101] The velocity and displacement data sequences in the horizontal and vertical directions are obtained using numerical integration methods. Acceleration, velocity, and displacement curves along the X and Z axes during the braking process are plotted. The characteristic values ​​of these curves are analyzed to calculate the braking parameters of the escalator in both the horizontal and vertical directions. During the braking process, the actual running direction of the escalator steps is downward at an incline. The sum of the velocity vectors in the X and Z directions represents the actual running velocity of the steps, and the sum of the displacement vectors represents the step displacement. By comprehensively analyzing the velocity and displacement vector sum curves, the average braking deceleration and total stopping distance can be calculated.

[0102] Furthermore, in the spectral analysis of abnormal vibrations in elevators or escalators, a Fast Fourier Transform (FFT) is performed on the vibration data to obtain the frequency spectrum. By analyzing the FFT data sequence and sorting the amplitudes, the frequency corresponding to the maximum vibration energy can be obtained, which is generally the motor vibration frequency. If an abnormal vibration frequency exists, an abnormal peak will appear in the frequency spectrum, and the corresponding frequency is the abnormal vibration frequency. By analyzing the size and running speed of each moving part of the elevator or escalator, the natural frequency of each part can be calculated. By comparing the abnormal frequency with the natural frequency, the mechanical part that causes the abnormal vibration can be identified.

[0103] Furthermore, when analyzing the verticality of the elevator car installation or the tilt angle of the escalator, the gravitational acceleration (approximately 9.8 m / s²) is obtained when the module is stationary. 2 The acceleration projection components on the three acceleration data axes, and the vector sum of the three projection components is the vertically downward gravitational acceleration; the angle between the three data axes XYZ and the horizontal plane, i.e. the horizontal tilt angle, can be calculated according to the vector decomposition model; when the module is placed horizontally, the tilt angle of the Z axis is 90 degrees and the tilt angles of the X and Y axes are 0 degrees, which can measure parameters such as the tilt angle of the escalator and the verticality of the elevator car installation.

[0104] In summary, the elevator multi-parameter measurement method based on a MEMS triaxial accelerometer provided in this embodiment of the invention has the following advantages:

[0105] 1. MEMS accelerometers can be used to perform compatibility testing of multiple components and parameters, such as elevator cars, escalator steps, escalator handrails, and main units, using a single module;

[0106] 2. By comprehensively employing algorithms such as vibration frequency weighting, digital filtering, numerical integration, curve fitting, fast Fourier transform, and mathematical statistics, vibration comfort parameters and operating parameters of elevators or escalators are analyzed, such as speed, start-stop acceleration and deceleration, lifting height, braking time, braking distance, braking deceleration, abnormal vibration frequency, and tilt angle.

[0107] Third, relying on the powerful data processing capabilities of handheld smart terminals, test results can be obtained immediately on-site in elevators or escalators through text, curves, and other means, and original table data such as electronic test reports and plotted curves can be exported on-site, eliminating the need to import the data into a computer for analysis after testing.

[0108] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for measuring multiple parameters of an elevator based on a MEMS triaxial accelerometer, characterized in that, Includes the following steps: A triaxial accelerometer is used to measure various parameters of a vertical elevator. The measuring device has three conical feet at the bottom of its module. When measuring vibration comfort, the measuring device is placed on the car floor, with the X-axis or Y-axis perpendicular to the elevator door. The operator stands inside the car, holding a data terminal, and operates the elevator from the bottom floor to the top floor or from the top floor to the bottom floor. The three-axis vibration acceleration signals are recorded during the elevator operation. The data terminal analyzes the data to obtain vibration characteristic parameters, so as to quantitatively evaluate the car vibration and ride quality. During the braking performance test, the measuring device module is placed on the car floor. During the data acquisition process, personnel leave the elevator car. The test ends after the braking is completed and the elevator is leveled. The data terminal automatically performs data analysis. When testing the vibration of the ferromagnetic components of the elevator host, there is no need to use support legs. The magnet inside the measuring device is directly attached to the metal surface of the component under test, and the vibration condition is tested; or, the sensor is attached to the surface of the object under test by installing a circular magnetic base at the bottom of the module of the measuring device. A triaxial accelerometer is used to measure various parameters of escalators or moving walkways: Place the measuring device on the step, adjust the position of the support legs so that all three support legs simultaneously engage with the grooves on the surface of the step. The operator stands on a step near the step where the measuring device module is located, presses the switch button to establish communication with the data terminal, and operates the escalator after the test begins. During operation, the vibration of the steps is tested to achieve the upward vibration comfort test or downward vibration comfort test of the escalator steps, or to test the parameters of the escalator's average braking deceleration and braking distance. Similarly, when testing the vibration comfort of moving walkway treads, the measuring device should be placed at both the inclined and horizontal sections. When testing the vibration of the handrail belt of an escalator or moving walkway, the operator stands on the escalator step or moving walkway tread, holds the vibration measuring device, removes the three support feet at the bottom of the module, and makes the X direction of the measuring device point to the direction of elevator operation. The operator then operates the escalator or moving walkway and tests the vibration of the handrail belt during operation. During the test, the vibration of the two handrail belts in both the upward and downward directions was measured, and the running speed of the handrail belts was measured over a short period of time. When analyzing the vibration comfort of a straight elevator, due to the unevenness of the car floor and the assembly error of the module circuit board, it is necessary to compensate for the horizontal tilt angle of the module and deduct the DC component of the gravitational acceleration before calculating the vibration comfort, so as to obtain an orthogonal triaxial vibration acceleration data sequence. Due to the influence of human physiological structure, different vibration frequencies will lead to differences in passengers' perception of vibration amplitude. In order to make the vibration test results more consistent with the human experience of elevator comfort, it is necessary to perform frequency weighting on vibration acceleration.

2. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 1, characterized in that, When analyzing the vibration comfort of a straight elevator, due to the unevenness of the car floor and the assembly error of the module circuit board, it is necessary to compensate for the horizontal tilt angle of the module and deduct the DC component of the gravitational acceleration before calculating the vibration comfort, so as to obtain an orthogonal triaxial vibration acceleration data sequence. The angles between the X-axis, Y-axis, and Z-axis and the horizontal plane are calculated based on the projected components of the gravitational acceleration on the three data axes when the module is stationary. The calculation principle is as follows: , , ; In the formula: a is the angle between the module's X-axis and the horizontal plane (rad), b is the angle between the module's Y-axis and the horizontal plane (rad), g is the angle between the module's Z-axis and the horizontal plane (rad), and a x The projection component of gravitational acceleration on the X-axis when the module is stationary (m / s²) 2 a y The projection component of gravitational acceleration on the Y-axis when the module is stationary (m / s²) 2 a z The projection component of gravitational acceleration on the Z-axis when the module is stationary (m / s²) 2 .

3. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 2, characterized in that, During calculation, a x a y and a z The average acceleration over 1 second when the module is stationary is taken; the original acceleration is corrected according to the projection relationship of gravitational acceleration on the three measurement axes to ensure that the acceleration data used in subsequent analysis are absolute horizontal and vertical data. The correction method is as follows: , , ; In the formula: A z The corrected Z-axis acceleration in m / s² 2 A x The corrected X-axis acceleration in m / s² 2 A y The corrected Y-axis acceleration in m / s² 2 .

4. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 3, characterized in that, Due to the influence of human physiological structure, different vibration frequencies will lead to differences in passengers' perception of vibration amplitude. In order to make the vibration test results more consistent with the human experience of elevator comfort, it is necessary to perform frequency weighting on vibration acceleration. Frequency weighting includes four filtering processes: high-pass and low-pass second-order Butterworth filtering, av transform filtering, and high-pass filtering, to obtain the time-domain curves of the three-axis acceleration after frequency weighting. The peak-to-peak value sequence of the three axes is obtained through curve analysis. The peak-to-peak values ​​of the vibration are sorted, and the maximum peak-to-peak value and A95 peak-to-peak value are solved to quantitatively evaluate the vibration comfort.

5. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 1, characterized in that, In the escalator vibration comfort analysis, the total frequency weighting function is the product of the functions of four filters: high-pass and low-pass second-order Butterworth filter, av transform filter, and higher-order filter; the Z-transform transfer function of each filter process is: ； in, Here, 'a' represents the Z-transform output value, and 'a' represents the numerator vector of the digital filter. b is the denominator vector of the digital filter: The Z vector is: .

6. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 5, characterized in that, Different frequency weighting methods are used for different vibration sensing parts, vibration directions, and human postures, corresponding to different filter parameters; Standing horizontal whole-body vibration using frequency weighting W d Standing vertical whole-body vibration using frequency weighting W k The hand-transmitted vibration uses frequency-weighted W h Different filter vectors a and b are used in different filtering processes under different frequency weighting methods. The recursive calculation formula for digital filtering of the m-th acceleration data is as follows: ； In the formula, x is the data sequence before filtering, y is the data sequence after filtering, and m is the number of the filtered data in the sequence.

7. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 6, characterized in that, For step vibration, the RMS value of the triaxial frequency-weighted data needs to be calculated separately; for handrail vibration, the downward X-axis value of the handrail needs to be calculated. h The RMS value of the directional frequency-weighted data, with a time constant of 1 second, is calculated using the following formula for the Nth RMS data: ； In the formula, n is the number of acceleration data within a 1s time constant, and a is the acceleration value after frequency weighting; For stepped vibration, the overall vibration energy is evaluated using a triaxial RMS vector sum: ； In the formula, For the sum of vibration vectors, The RMS value of the X-axis vibration. The RMS value of the Y-axis vibration. This represents the RMS value of the Z-axis vibration.

8. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 1, characterized in that, When analyzing the acceleration, deceleration, speed, and displacement of elevators or escalators during start-stop, before performing the elevator motion characteristic analysis, a second-order Butterworth low-pass filter is applied to the raw acceleration data of the sensor's Z-axis, with a filter cutoff frequency of 10 Hz. Acceleration and deceleration reflect the pressure exerted on the human body by the elevator car floor. Quantifying the maximum acceleration and maximum deceleration can be used to evaluate whether the elevator's operation control settings are reasonable in relation to passenger quality results. The maximum acceleration is the maximum value of the acceleration signal when the elevator starts, and the maximum deceleration is the maximum absolute value of the deceleration signal during the elevator's braking process. The A95 acceleration value is statistically calculated within the range of 5% to 95% of the maximum speed during acceleration, and 95% of the acceleration data within this range are less than this value. The A95 deceleration value is statistically calculated within the range of 95% to 5% of the maximum speed during deceleration, and 95% of the absolute values ​​of the deceleration data within this range are less than this value. The maximum speed is the maximum absolute value of the speed throughout the entire elevator's operating cycle; the statistically calculated limit range of the V95 speed is from the maximum speed V during the acceleration phase. max1 95% corresponds to the maximum speed V during the deceleration phase, which is 1 second after the data point. max2 95% corresponds to the first second of the time point in the data. Within this calculation limit, 95% of the velocity values ​​are less than the V95 velocity.

9. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 8, characterized in that, The Z-axis acceleration after Butterworth filtering is integrated using the composite 1 / 3 Simpson numerical integration method to calculate the velocity sequence. The numerical integral velocity calculation formula at time t is as follows: ； In the formula, v(t) is the velocity at time t, in m / s, h is the time step of the acceleration data sequence, and a(0) is the initial acceleration, in m / s. 2 a(t) is the acceleration at time t in m / s². 2 n is the number of data points in the integration interval; The composite 1 / 3 Simpson method is used to numerically integrate the velocity data, and the elevator displacement sequence is calculated to obtain the lifting height information. The formula for calculating the numerically integrated displacement at time t is: 。 10. The elevator multi-parameter measurement method based on a MEMS triaxial accelerometer according to claim 9, characterized in that, When analyzing the braking parameters of straight elevators or escalators, in order to reflect the actual running acceleration of the steps on the Z-axis, the gravitational acceleration bias needs to be subtracted. During the calculation, the average value of the Z-axis acceleration data within 3 seconds after the braking ends and before the data acquisition stops is taken as the gravitational acceleration bias. The velocity and displacement data sequences in the horizontal and vertical directions are obtained using numerical integration methods. Acceleration, velocity, and displacement curves along the X and Z axes during the braking process are plotted. The characteristic values ​​of these curves are analyzed to calculate the braking parameters of the escalator in both the horizontal and vertical directions. During the braking process, the actual running direction of the escalator steps is downward at an incline. The sum of the velocity vectors in the X and Z directions represents the actual running velocity of the steps, and the sum of the displacement vectors represents the step displacement. By comprehensively analyzing the velocity and displacement vector sum curves, the average braking deceleration and total stopping distance can be calculated.

Images