A method, system and device for locating the force point of ladder detection equipment

Abstract

The present invention belongs to the field of automatic control, and provides a method, system and device for locating the force point of a ladder detection device, which can identify abnormalities by continuing to monitor the relationship between vertical force data and displacement data, the relationship between vertical force data and tilt angle data, and the relationship between displacement data and tilt angle data after the compression turning point, so as to correct the abnormalities and continue testing. Not only the accuracy and safety of the ladder force point positioning are improved, but also the test time and cost are greatly reduced through automatic control technology.

Description

Technical Field

[0001] The invention belongs to the field of automatic control, and in particular relates to a method, system and equipment for locating a focus point of a ladder detection device. Background Art

[0002] As a common tool in daily life and industrial production, the safety and durability of ladders are of vital importance. In order to ensure the stability and reliability of ladders in various usage scenarios, manufacturers usually conduct repeated pressure tests to verify the performance of ladders under different loads. In the prior art, the pressure test of ladders is usually carried out by applying vertical pressure, focusing on the stress conditions of key parts of the ladder. However, the existing detection methods have many shortcomings in the positioning of the force point and the test accuracy. For example, the patent document with publication number CN201974290U discloses a ladder bearing pressure test device, and it is difficult for the detection equipment to accurately find the optimal force point of the ladder. Due to the complexity of the ladder structure and the mechanical properties of different materials, a slight deviation in the pressure point may lead to inaccurate test results, and even cause irreversible damage to the ladder during the pressure application process, especially when the pressure is too high, the fragile new product model is easily crushed. In the traditional method, manual adjustment is overly relied on when finding the force point, and the test process requires technicians to try repeatedly based on experience, which not only affects the test efficiency, but also increases the risk of product damage. Existing ladder testing equipment usually applies pressure to the ladder mechanically and manually measures parameters such as force and displacement. This method has poor real-time performance and is difficult to detect and correct problems in the force application process in a timely manner. When the applied pressure is too large or the force point is offset, it is often difficult to detect in time, which may eventually cause the ladder to deform or even damage. For example, the patent document with publication number CN217466191U discloses a new material ladder pressure test device and test system. In the process of finding the force point, the pressure cannot be dynamically adjusted through the real-time feedback mechanism, which is prone to uneven force or excessive force, making the test data inaccurate, thereby affecting the overall inspection quality of the product. Since the traditional method requires repeated manual adjustment of the pressure and the position of the force point, the testing process is very time-consuming. At the same time, manual operation relies on the experience of technicians, is inefficient, and is easily affected by human factors. In addition, when performing multiple rounds of pressure testing, there is a lack of automated positioning and adjustment means, which further increases the complexity of the testing work. In the prior art, abnormal conditions (such as equipment failure or operational errors) that occur during the pressure of the ladder are difficult to be discovered in time. The lack of comprehensive analysis of vertical force, displacement, tilt angle and other data results in the equipment being unable to automatically identify problems and correct them when operating abnormally, increasing the risk of equipment damage or distorted test results. Existing equipment is unable to respond and adjust promptly to minor anomalies that occur during the test, which may cause data distortion and affect the accuracy of the test results. Traditional ladder pressure testing methods have obvious technical defects in inaccurate positioning of the point of application, insufficient real-time monitoring, low efficiency, and difficulty in identifying abnormal situations. These deficiencies not only lead to low efficiency and increased costs in ladder testing, but also easily lead to the risk of product damage. Summary of the invention

[0003] The purpose of the present invention is to provide a method, system and device for locating the focus point of a ladder detection device, so as to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0004] In order to achieve the above object, according to one aspect of the present invention, a method for locating a force point of a ladder detection device is provided, the method comprising the following steps:

[0005] At the point where the cylinder contacts the ladder, it is used to measure the vertical force data applied by the cylinder in real time;

[0006] Between the cylinder and the ladder, the displacement data of the cylinder is monitored in real time;

[0007] At the part where the ladder is stressed, the strain data generated by the ladder after being stressed is measured in real time;

[0008] By measuring at each supporting point of the ladder, the inclination angle data of the ladder can be obtained in real time;

[0009] According to the growth trend of vertical force data and strain data in the time direction, the compression turning point of the ladder is monitored;

[0010] After the compression turning point, the ladder is continuously monitored to identify abnormalities in terms of the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the tilt angle data, and the relationship between the displacement data and the tilt angle data, so as to correct the abnormalities and continue testing.

[0011] Furthermore, a multi-axis force sensor is used to measure the vertical force applied by the cylinder in real time, and the multi-axis force sensor is installed at the point where the cylinder contacts the ladder.

[0012] Further, a linear displacement sensor is used to measure the distance moved by the cylinder, and the linear displacement sensor is installed between the cylinder and the ladder.

[0013] Furthermore, a strain gauge sensor is used to measure the stress and / or strain value generated by the ladder after being subjected to force. The strain gauge sensor is pasted on key parts of the ladder where force is applied, including rungs and / or pedals. The strain gauge sensor can calculate the stress distribution by measuring the deformation of the ladder material; an angle sensor is used to measure the inclination angle of the ladder on an uneven surface. The angle sensor is installed at each supporting point of the ladder.

[0014] Furthermore, according to the growth trend of the vertical force data and the strain data in the time direction, the method for monitoring the compression turning point of the ladder is: calculating the second-order derivative of the vertical force data on the ladder with time, calculating the second-order derivative of the strain data with time at time t, and then selecting the smaller value between the second-order derivative of the vertical force and the second-order derivative of the strain as the turning point signal. When the value of the turning point signal slows down or stops growing, it is the compression turning point.

[0015] Furthermore, according to the growth trend of the vertical force data and the strain data in the time direction, the method for monitoring the compressive turning point of the ladder is as follows:

[0016] The value of the vertical force data corresponding to the current moment is obtained as the real-time vertical force value, and the value of the strain data corresponding to the current moment is obtained as the real-time strain value; the arithmetic mean of the values ​​of the vertical force data at each sampling moment before the current moment is calculated as the previous vertical force mean, and the arithmetic mean of the values ​​of the strain data at each sampling moment before the current moment is calculated as the previous strain mean; the difference between the real-time vertical force value and the previous vertical force mean is used as the previous vertical force distance, the difference between the real-time strain value and the previous strain mean is used as the previous strain distance, the ratio of the exponential value of the previous vertical force distance to the exponential value of the previous vertical force mean is used as the previous vertical force trend, and the ratio of the previous strain distance to the previous strain mean is used as the previous strain trend; according to the previous vertical force trend and the previous strain trend, the compression turning point of the ladder is monitored.

[0017] Furthermore, after the compression turning point, the ladder is continuously monitored for the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the tilt angle data, and the relationship between the displacement data and the tilt angle data, to identify anomalies, and the specific method is:

[0018] After the stress turning point, a sliding time window is used for sampling;

[0019] An array consisting of the values ​​of the vertical force data corresponding to each sampling moment in each sliding time window in time sequence is used as the vertical force data of the sliding time window, an array consisting of the values ​​of the displacement data corresponding to each sampling moment in each sliding time window in time sequence is used as the displacement data of the sliding time window, and an array consisting of the values ​​of the tilt angle data corresponding to each sampling moment in each sliding time window in time sequence is used as the tilt angle data of the sliding time window;

[0020] Monitor the vertical force data, displacement data and tilt angle data of multiple sliding time windows. If the numerical relationship between the vertical force data and the displacement data, and the numerical relationship between the vertical force data and the tilt angle data become closer over time, and the numerical relationship between the displacement data and the tilt angle data deviates more and more over time, it is judged that the state of the ladder is abnormal.

[0021] The present invention also provides a system for locating the fulcrum point of a ladder detection device, the system for locating the fulcrum point of a ladder detection device comprising: a processor, a memory, and a computer program stored in the memory and executable on the processor, the processor implementing the steps in the method for locating the fulcrum point of a ladder detection device when executing the computer program, the system for locating the fulcrum point of a ladder detection device can be run in computing devices such as desktop computers, laptop computers, PDAs, and cloud data centers, the executable system may include, but is not limited to, a processor, a memory, and a server cluster, the processor executing the computer program runs in the following system units:

[0022] The data acquisition unit is used to: measure the vertical force data applied by the cylinder in real time at the contact point between the cylinder and the ladder; monitor the displacement data of the cylinder in real time between the cylinder and the ladder; measure the strain data generated by the ladder after the force is applied in real time at the position where the ladder is subjected to force; and obtain the inclination angle data of the ladder in real time by measuring at each supporting point of the ladder;

[0023] A turning point monitoring unit is used to monitor the compressive turning point of the ladder according to the growth trend of the vertical force data and the strain data in the time direction;

[0024] The abnormality identification unit is used to identify abnormalities after the compression turning point by continuing to monitor the ladder, including the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the tilt angle data, and the relationship between the displacement data and the tilt angle data, so as to correct the abnormalities and continue the test.

[0025] Correspondingly, the present invention also provides an electronic device, a readable storage medium and a computer program product:

[0026] An electronic device comprises: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for locating the fulcrum of a ladder detection device and the methods of each step therein.

[0027] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause the computer to execute the method for locating the force point of a ladder detection device and the steps thereof.

[0028] A computer program product comprises a computer program. When the computer program is executed by a processor, the method for locating a force point of a ladder detection device and the methods for each step thereof are implemented.

[0029] The beneficial effects of the present invention are as follows: the present invention provides a method, system and device for locating the force point of a ladder detection device, in order to solve the problem of the fragility of the aluminum alloy ladder in the process of finding the force point, ensure a durable testing process, and help the device to achieve the force point positioning in the ladder detection. The traditional pressure testing method is easy to apply excessive force in the process of finding the force point, resulting in damage to the ladder or its model, especially in the new product development stage, the fragile model is more vulnerable. The method of the present invention monitors the vertical force, displacement and strain data applied by the cylinder in real time. This method can prevent the force from being suddenly too large, thereby protecting the ladder and the model from damage, and improving the safety and reliability of the test. The force point positioning process is cumbersome and time-consuming, and manual detection is prone to errors, affecting the accuracy of the test results and the test efficiency. The traditional ladder force point search process is time-consuming, and requires technicians to repeatedly adjust manually, which greatly increases the test cycle and labor costs. In the detection process, data abnormalities may occur due to equipment failure or operational errors, which are difficult to detect and correct in time by traditional methods, resulting in inaccurate tests or product damage. Through the correlation analysis of physical quantities such as vertical force, displacement, and tilt angle, this method can detect equipment anomalies or operational problems in a timely manner and issue early warning signals to ensure the stability and consistency of the detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other features of the present invention will become more obvious by describing in detail the embodiments shown in the accompanying drawings. The same reference numerals in the accompanying drawings of the present invention represent the same or similar elements. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other accompanying drawings can be obtained based on these accompanying drawings without creative work. In the accompanying drawings:

[0031] Figure 1 Shown is a flow chart of a method for locating a force point of a ladder detection device;

[0032] Figure 2 The figure shows a system structure diagram of the fulcrum positioning of a ladder detection device. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention, so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments and features in the embodiments of this application can be combined with each other without conflict.

[0034] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] like Figure 1 The flowchart of the method for locating the force point of a ladder detection device according to the present invention is shown below. Figure 1 A method, system and device for locating a focus point of a ladder detection device according to an embodiment of the present invention will be described.

[0036] The present invention proposes a method for locating the force point of a ladder detection device, which applies pressure to the ladder by mechanical means (applies force to the ladder to be detected by a cylinder), and gradually controls and adjusts the force of the cylinder on the ladder. The method specifically includes the following steps:

[0037] At the contact point between the cylinder and the ladder, it is used to measure the vertical force data applied by the cylinder in real time; between the cylinder and the ladder, the displacement data of the cylinder is monitored in real time; at the force-bearing part of the ladder, the strain data generated by the ladder after the force is applied is measured in real time; by measuring at each supporting point of the ladder, the inclination angle data of the ladder is obtained in real time;

[0038] According to the growth trend of vertical force data and strain data in the time direction, the compression turning point of the ladder is monitored;

[0039] After the compression turning point, the ladder is continuously monitored to identify abnormalities in terms of the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the tilt angle data, and the relationship between the displacement data and the tilt angle data, so as to correct the abnormalities and continue testing.

[0040] In some specific embodiments, a full closed-loop force control is used to dynamically simulate the loading of the aluminum ladder through a servo motor, a servo cylinder (cylinder 1 and cylinder 2), a servo controller and a computer. The system uses a computer host to collect force sensor signals at high speed and feeds the signals back to the servo controller in real time to control the machine action. The computer dynamically displays the real-time curve of force and frequency. The test procedure steps may include:

[0041] a) Confirmation of ladder condition: Confirm that the free-standing ladder used for the test has no defects.

[0042] b) Ladder unfolding and placement: unfold the free-standing ladder to its maximum use state and place it on the test plane. The bottom ends of the four ladder frames of the fixed ladder, and the bottom end of the ladder frame on one of the supporting sides should be placed on a 20 mm high stainless steel plate to simulate an uneven surface.

[0043] c) Determine the force application position: determine the rod / pedal at the midpoint L2 / 2 (half the length) on the climbing side, or the upper rod / pedal closest to this position (if there is no rod / pedal at L2 / 2, the length of cylinder 2 is L2).

[0044] d) Installation of cylinder 2: Place the cylinder 2 with pad on the determined tread / pedal, and the distance between the center line and the inside of the ladder frame should be 70 mm ± 5 mm. Adjust the height of cylinder 2 so that the vertical distance between the lower surface of the pad and the upper surface of the tread / pedal is 5 mm ± 2 mm.

[0045] e) Installation of cylinder 1: Place cylinder 1 with gasket on the top rung / pedal / platform, the distance between the center line and the inside of the ladder frame should be 70 mm ± 5 mm.

[0046] Adjust the height of cylinder 1 so that the vertical distance between the lower surface of the pad and the upper surface of the treadle / pedal is 5 mm ± 2 mm.

[0047] f) Ladder frame fixing: Use elastic ropes or webbing to restrain the four ladder frames separately to ensure that the force position of the ladder remains basically unchanged during the test.

[0048] g) Load application: Adjust cylinder 1 and cylinder 2 to ensure that they can apply a load of 1500 N ± 50 N respectively.

[0049] h) Start the test: Start the test in accordance with the specified requirements.

[0050] i) Loading duration: Loading continues until one of the following occurs: the free-standing ladder fails, or the free-standing ladder reaches the required number of cycles for the test.

[0051] j) Record results: Record the test results.

[0052] Judgment criteria: If the ladder reaches the required number of test cycles and functions normally, it is considered to have passed; visible cracks are allowed, but after completing the preset tests, it must meet the requirements of its judgment criteria.

[0053] Sensors can be installed at the contact points between the cylinder and the ladder. At the contact points between the cylinder and the ladder, high-precision force sensors are installed to measure the vertical force applied by the cylinder in real time. These sensors must be able to withstand high loads and have high sensitivity to ensure the accuracy of the data. The vertical force sensor at each contact point transmits data to the control system in real time through the data acquisition system.

[0054] In the displacement system of the cylinder, a displacement sensor is installed. This sensor is used to monitor the up and down movement of the cylinder in real time and collect displacement data. The displacement sensor can be an optical encoder or LVDT (sometimes called linear variable differential transformer) to ensure high resolution and high frequency acquisition of displacement data.

[0055] Strain gauges are installed at key locations where the ladder is stressed, such as where the cylinder contacts the steps on the ladder. The strain gauges measure the strain changes of the ladder under stress in real time. Strain gauges are arranged at different stress-bearing locations of the ladder, such as the rungs and ladder frames, to ensure that the entire stress-bearing structure is covered. These strain gauges are connected to force sensors and transmit data through a data acquisition system.

[0056] Accelerometers or angle sensors are installed at each supporting point of the ladder, such as the supporting feet of the ladder, to measure the inclination angle of the ladder in real time. Based on the three-dimensional acceleration data collected by these sensors, the inclination angle change of the ladder under different test conditions is calculated to ensure that the angle of the ladder during the test is within a reasonable range.

[0057] Furthermore, a multi-axis force sensor is used to measure the vertical force applied by the cylinder in real time, and the multi-axis force sensor is installed at the point where the cylinder contacts the ladder.

[0058] Furthermore, a linear displacement sensor is used to calculate the deformation degree of the ladder after being subjected to force by measuring the distance moved by the cylinder, and the linear displacement sensor is installed between the cylinder and the ladder.

[0059] Furthermore, a strain gauge sensor is used to measure the stress and / or strain value generated by the ladder after being subjected to force. The strain gauge sensor is pasted on key parts of the ladder where force is applied, including rungs and / or pedals. The strain gauge sensor can calculate the stress distribution by measuring the deformation of the ladder material; an angle sensor is used to measure the inclination angle of the ladder on an uneven surface. The angle sensor is installed at each supporting point of the ladder.

[0060] Furthermore, according to the growth trend of vertical force data and strain data in the time direction, the monitoring method of the compression turning point can be: calculating the second-order derivative of the vertical force data on the ladder with time, calculating the second-order derivative of the strain data with time at time t, and then selecting the smaller value between the second-order derivative of the vertical force and the second-order derivative of the strain as the turning point signal, and the moment when the value of the turning point signal slows down or stops growing is the compression turning point.

[0061] Further, according to the growth trend of the vertical force data and the strain data in the time direction, the monitoring method of the compression turning point may also be:

[0062] The value of the vertical force data corresponding to the current moment is obtained as the real-time vertical force value, and the value of the strain data corresponding to the current moment is obtained as the real-time strain value; the arithmetic mean of the values ​​of the vertical force data at each sampling moment before the current moment is calculated as the previous vertical force mean, and the arithmetic mean of the values ​​of the strain data at each sampling moment before the current moment is calculated as the previous strain mean; the difference between the real-time vertical force value and the previous vertical force mean is used as the previous vertical force distance, the difference between the real-time strain value and the previous strain mean is used as the previous strain distance, the ratio of the exponential value of the previous vertical force distance to the exponential value of the previous vertical force mean is used as the previous vertical force trend, and the ratio of the previous strain distance to the previous strain mean is used as the previous strain trend; according to the previous vertical force trend and the previous strain trend, the compression turning point of the ladder is monitored.

[0063] The control system acquires vertical force and strain data from the force sensor and strain gauge in real time and synchronizes these data with time. By detecting the growth trend of the data, especially in the early stage of the test, the stress state of the ladder is analyzed.

[0064] In some less preferred embodiments, the monitoring of the pressure turning point may be:

[0065] When the vertical force data and strain data show a nonlinear growth trend in the time direction, the system automatically identifies the compressive turning point.

[0066] The time of data sampling is recorded as variable t, and the vertical force data at time t is calculated to represent the real-time force applied by the cylinder to the ladder during the test;

[0067] Calculate the strain data at time t, which represents the deformation of the key stress-bearing parts of the ladder after the ladder is subjected to stress;

[0068] Calculate the second derivative of the vertical force data at time t with time t, which represents the acceleration of the vertical force change. By calculating the acceleration of the force change, it can be determined whether the force growth begins to slow down or stop, which represents a turning point in compression.

[0069] The second derivative of the strain data at time t with time t is calculated to represent the acceleration of strain change, which reflects whether there is a significant change in the rate of deformation of the ladder.

[0070] Then, the second derivative of the vertical force and the second derivative of the strain are calculated, and the smaller value is selected as the signal of the turning point. This is because the turning point usually occurs when the rate of change of one of the two slows down significantly. In this way, the key point of the change of the vertical force and strain data, that is, the turning point, is found. The second derivative of the vertical force and the second derivative of the strain are used to represent the growth trend of the vertical force data and the strain data in the time direction. By comparing the second derivatives of force and strain, it is identified which one slows down or stops growing first. This point indicates that the ladder may have reached its pressure bearing limit or is close to the critical point of the test.

[0071] However, the above suboptimal implementation method originally relied on the differentiability of the second-order derivative of the vertical force and the second-order derivative of the strain. When the above suboptimal implementation method was actually run on the factory's ladder automation assembly line, its time complexity of derivation showed problems. In addition, in addition to the unexpected time complexity, the automatic control program also reported a bug that the second-order derivative was not differentiable, causing the value to not exist, which had a great impact on the production line. Therefore, we considered whether it was possible to bypass the second-order derivative between the two physical quantities to avoid program failures, and made some optimizations to the suboptimal implementation method.

[0072] In some preferred embodiments, the monitoring of the pressure turning point may be:

[0073] Similarly, the time of data sampling is recorded as variable t, and each sampling moment before time t is traversed. If t is the current moment, the value of the vertical force data corresponding to the current moment is obtained as the real-time vertical force value, and the value of the strain data corresponding to the current moment is obtained as the real-time strain value; the arithmetic mean of the values ​​of the vertical force data at each sampling moment before the current moment is calculated as the prior vertical force mean, and the arithmetic mean of the values ​​of the strain data at each sampling moment before the current moment is calculated as the prior strain mean; the difference between the real-time vertical force value and the prior vertical force mean is taken as the prior vertical force distance, and the difference between the real-time strain value and the prior strain mean is taken as the prior strain distance. The ratio of the exponential value of the prior vertical force distance to the exponential value of the prior vertical force mean is taken as the prior vertical force trend, and the ratio of the prior strain distance to the prior strain mean is taken as the prior strain trend. In this way, the growth range of the preceding vertical force distance and the preceding strain distance can be better compared and highlighted. The preceding vertical force trend and the preceding strain trend are used to represent the growth trend of the vertical force data and the strain data in the time direction, which can bypass the second-order derivative between the two physical quantities to avoid program failures. In addition, in the distance comparison of the preceding strain data and the vertical force data to calculate the preceding vertical force mean and the preceding strain mean, the same growth trend statistics of the second-order derivative of the vertical force and the second-order derivative of the strain can be achieved. Then, according to the preceding vertical force trend and the preceding strain trend, the compression turning point of the ladder is monitored.

[0074] Among them, in the first implementation method of monitoring the compression turning point of the ladder, the smaller value of the preceding vertical force trend and the preceding strain trend is selected as the signal of the turning point during the original test. When the signal of the turning point slows down or stops growing, the time point when the slowdown or stop growing is judged as the compression turning point of the ladder. However, in order for the signal of the turning point to slow down or stop growing, the second-order derivative still needs to be calculated in the underlying code to measure the slowdown of growth. Therefore, in the first implementation method of monitoring the compression turning point of the ladder, the compression turning point of the ladder is judged by the product of the preceding vertical force trend and the preceding strain trend. If the product of the preceding vertical force trend and the preceding strain trend is negative, it means that at least one of the growth trends of the vertical force data and the strain data in the time direction is negative, that is, the correlation direction of the vertical force data and the strain data in the time direction is nonlinear, and the nonlinear occurrence interval of the force-strain relationship usually corresponds to the yield point of the material, which is the point where the material begins to undergo permanent deformation.

[0075] Furthermore, after the compression turning point, the ladder is continuously monitored for the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the tilt angle data, and the relationship between the displacement data and the tilt angle data, to identify anomalies, and the specific method is:

[0076] After the stress turning point, a sliding time window is used for sampling;

[0077] An array consisting of the values ​​of the vertical force data corresponding to each sampling moment in each sliding time window in time sequence is used as the vertical force data of the sliding time window, an array consisting of the values ​​of the displacement data corresponding to each sampling moment in each sliding time window in time sequence is used as the displacement data of the sliding time window, and an array consisting of the values ​​of the tilt angle data corresponding to each sampling moment in each sliding time window in time sequence is used as the tilt angle data of the sliding time window;

[0078] Monitor the vertical force data, displacement data and tilt angle data of multiple sliding time windows. If the numerical relationship between the vertical force data and the displacement data, and the numerical relationship between the vertical force data and the tilt angle data become closer over time, and the numerical relationship between the displacement data and the tilt angle data deviates more and more over time, it is judged that the state of the ladder is abnormal.

[0079] During the test, the position of the force point can be dynamically adjusted according to the real-time stress and displacement feedback data to correct the abnormality and continue the test: if the stress at a certain force point is too large, the system will automatically move the cylinder to an area with less stress to disperse the load and avoid excessive concentration. According to the set test standards (such as the number of cycles, damage standards, etc.), it will automatically stop after the test requirements are met and generate a final test report. Detect possible equipment failures or abnormal conditions (such as force sensor failure), automatically take corresponding corrective measures or notify the operator. Alternatively, when the force abnormality caused by excessive ladder deformation or cylinder position deviation is detected, the cylinder position can be quickly adjusted to correct the abnormality and continue the test. For example, adjust the distance from the center line of the cylinder to the inside of the ladder frame to ensure that it meets the requirement of 70 mm ± 5 mm; for example, use a stepper motor or servo motor to accurately adjust the height of the ladder so that the bottom of the ladder frame on one of the supporting sides is accurately placed on a stainless steel plate 20 mm high; or, when the force at any position deviates from the preset value, automatically adjust the position of the cylinder and the force applied to ensure that the loading force is always kept within the range of 1500N ± 50N.

[0080] In some prior arts, after the compression turning point, the trigger program continues to monitor the relationship between the three groups of data: the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the tilt angle data, and the relationship between the displacement data and the tilt angle data. Among them, the system can be ensured to be in normal working condition by monitoring the relationship between the vertical force and the displacement data. If the displacement changes abnormally with the force, such as nonlinear or unreasonable changes, the system will identify it as an abnormality in the relationship between the vertical force and the displacement data. At the same time, if the inclination angle of the ladder should be kept within the design range when the cylinder applies force, if the angle changes beyond the predetermined range, there may be equipment failure or operation problems. The inclination abnormality can be identified by monitoring the vertical force and angle change curves. If the inclination abnormality exceeds the preset threshold, it is judged as an inclination angle abnormality. In addition, for displacement and tilt angle, if the ladder is abnormally tilted or the displacement speed is too fast during the vertical displacement process, the relationship between the displacement change rate and the angle change rate can be calculated to monitor whether there is an abnormality.

[0081] In this way, every time new data is collected, the relationship between the above three groups of parameters is automatically compared to determine whether there is an abnormality. If unreasonable data jumps or discontinuities are detected in any of the relationships between the vertical force data and the displacement data, the vertical force data and the tilt angle data, and the displacement data and the tilt angle data, the state of the ladder's fulcrum will be judged as abnormal. After identifying the abnormality, the software system will automatically adjust the applied load and displacement speed of the cylinder, or adjust the tilt angle of the test ladder through the control program. After correction, the system will re-calibrate according to the new data to ensure stable operation of the system after adjustment. After completing an abnormality correction, the system continues to monitor all key parameters in real time, and continuously analyzes the relationship between parameters to ensure that no abnormalities occur in subsequent tests.

[0082] However, this method actually relies on preset thresholds for the three data items. But it is not easy to conceive of any thresholds in actual factory production. Moreover, if there are positioning deviations of some construction workers on the production line, the thresholds may fail.

[0083] In a preferred embodiment, after the compression turning point, the cylinder continues to apply pressure to the ladder to be tested, and monitors the vertical force data, displacement data and tilt angle data of the ladder to be tested in multiple different sampling time periods. Among them, in the form of a sliding time window, each sliding time window is used as a sampling time period, and preferably 1 minute is used as a sliding time window, and sampling is performed 3 to 5 times per minute. In each sampling time period, multiple different sampling moments are selected in the form of average sampling and stratified sampling, and the number of sampling moments in each sliding time window is equal. This is done because the plastic deformation of the ladder has a time period law. Each time the ladder is plastically deformed by the vertical pressure of the force point test, it takes time to recover to be compressed again, so the sampling of the data requires a cycle of rebound. There can be partial overlap between the sliding time windows, but they cannot overlap completely. Then, the values ​​of the vertical force data, displacement data and tilt angle data at each sampling moment are obtained respectively.

[0084] Preferably, each sliding time window can be sorted in chronological order, and an array composed of the values ​​of the vertical force data corresponding to each sampling moment in each sliding time window in chronological order is used as the vertical force data of the sliding time window, an array composed of the values ​​of the displacement data corresponding to each sampling moment in each sliding time window in chronological order is used as the displacement data of the sliding time window, and an array composed of the values ​​of the inclination angle data corresponding to each sampling moment in each sliding time window in chronological order is used as the inclination angle data of the sliding time window.

[0085] After the compression turning point, monitor the vertical force data, displacement data and tilt angle data of multiple sliding time windows. If the numerical relationship between the vertical force data and the displacement data, and the numerical relationship between the vertical force data and the tilt angle data become closer over time, and the numerical relationship between the displacement data and the tilt angle data deviates more and more over time, it is judged that the state of the ladder is abnormal.

[0086] In some embodiments, the correlation coefficient between the vertical force data of each sliding time window and the displacement data of the sliding time window is used to represent the relationship between the vertical force data and the displacement data, the correlation coefficient between the vertical force data of each sliding time window and the tilt angle data of the sliding time window is used to represent the relationship between the vertical force data and the tilt angle data, and the correlation coefficient between the displacement data of each sliding time window and the tilt angle data of the sliding time window is used to represent the relationship between the displacement data and the tilt angle data:

[0087] Record the numerical value (recorded as variable FDv) for representing the relationship between the vertical force data and the displacement data, the numerical value (recorded as variable FAv) for representing the relationship between the vertical force data and the tilt angle data, and the numerical value (recorded as variable DAv) for representing the relationship between the displacement data and the tilt angle data corresponding to each sliding time window;

[0088] When it is detected that in multiple consecutive sliding time windows, the absolute value of the difference between the numerical value (FDv) used to represent the relationship between the vertical force data and the displacement data and the numerical value (FAv) used to represent the relationship between the vertical force data and the tilt angle data continues to decrease over time, and at the same time, it is detected that the numerical value (DAv) used to represent the relationship between the displacement data and the tilt angle data continues to increase over time, it indicates that the state of the ladder is abnormal and a warning signal is sent.

[0089] This is done because, after the compression turning point, the change in the data relationship between vertical force, displacement and tilt angle can reflect the transition of the ladder from elastic deformation to plastic deformation, as well as the process of material fatigue or structural failure. By real-time monitoring of the relationship between these three, abnormal phenomena in the ladder structure can be captured and early warnings can be issued to prevent serious structural failure. The core of this theory is the principles of plastic deformation, structural stability and fatigue failure in material mechanics, indicating that the internal changes of the ladder under complex stress states will lead to abnormal external morphology, including tilt angle, displacement, etc.

[0090] First, the irreversibility of plastic deformation and structural degradation. When the ladder is subjected to repeated pressure, the material will gradually enter the plastic deformation region from the elastic region over time. Under normal conditions, the vertical force, displacement and tilt angle should maintain a certain correlation with each other, which is consistent with the elastic theory of the material. However, when the ladder enters the plastic deformation stage, especially after the compression turning point, the internal structure of the ladder material begins to degenerate, which is manifested in the increasingly close relationship between the vertical force and displacement data and the increasingly close relationship between the vertical force and tilt angle data. As the material gradually becomes plastic, the overall rigidity of the ladder decreases, which is manifested in the increase in deformation when pressure is applied. At this time, the change of vertical force and displacement tends to be linear, because the ladder loses part of its recovery ability (i.e., the elastic modulus decreases), resulting in a relationship between force and displacement that is closer to stability or linear growth. In this state, the deformation of the ladder will cause the overall force distribution of the structure to change. This makes the correlation between the tilt angle and the vertical force gradually increase, because when the ladder is subjected to pressure, the structural deformation is mainly reflected in the change of its tilt angle. However, during the plastic deformation process, as the deformation accumulates, the nonlinear effect in the structure will intensify.

[0091] The second level of consideration is the abnormal change in the relationship between displacement and tilt angle. When the relationship between displacement and tilt angle begins to gradually deviate from the normal trajectory, this often indicates failure of the local structure of the ladder or further instability in the stress concentration area. Under normal circumstances, the relationship between displacement and tilt angle should remain consistent with the uniform distribution of force. However, when stress concentration, crack propagation, or local structural failure occurs inside the ladder material, the displacement data increases significantly with the increase in pressure, but the change in tilt angle does not keep up, because some areas may have partially failed and deformation is concentrated in specific locations, causing the overall tilt angle of the ladder to be relatively stable or abnormally fluctuating. The tilt angle lags behind the change in displacement, indicating that the ladder structure has lost its uniform deformation characteristics, resulting in uneven force distribution.

[0092] In addition, it is also due to the consideration of material fatigue and the formation of micro cracks. Under long-term pressure, metal materials (such as aluminum alloys commonly used to make ladders, aluminum alloy ladders, etc.) may experience fatigue. Fatigue leads to the formation of micro cracks inside the material, which gradually expand and affect the mechanical properties of the ladder. Its displacement continues to expand as the pressure increases, but the presence of cracks will reduce the material's bearing capacity, causing the relationship between the structural inclination angle and displacement to become inconsistent. The failure of the crack propagation area causes the change in the inclination angle to deviate from expectations, manifested as strain localization, and this failure process is often sudden.

[0093] From the perspective of structural stability, when a system is in equilibrium, external forces, displacements and tilt angles should maintain a dynamic balance. If the relationship between tilt angle and displacement no longer matches, it means that the system is becoming unstable. Structural instability is often caused by the redistribution of internal forces (such as stress) or the loss of function of certain support points. This instability is often an important signal that the ladder is abnormal during compression.

[0094] In some test projects, sliding time window sampling was used, with a data sampling frequency of 3 times per minute and a sliding time window of 5 minutes. The following data shows the performance of the ladder under pressure in several consecutive time windows. Among them, it is divided into five time windows (T1 to T5), each time window has three groups of values, corresponding to the vertical force (N), displacement (mm), tilt angle (°) data, and the correlation coefficient between them:

[0095] Time window T1:

[0096] Vertical force: 1400N, 1450N, 1500N

[0097] Displacement: 4.0mm, 4.5mm, 5.0mm

[0098] Tilt angle: 0.5°, 0.6°, 0.65°

[0099] Vertical force-displacement correlation (FDv): 0.95

[0100] Vertical force-tilt angle correlation (FAv): 0.90

[0101] Displacement-tilt angle correlation (DAv): 0.85

[0102] Time window T2:

[0103] Vertical force: 1500N, 1550N, 1600N

[0104] Displacement: 5.0mm, 5.5mm, 6.0mm

[0105] - Tilt angle: 0.65°, 0.7°, 0.75°

[0106] Vertical force-displacement correlation (FDv): 0.97

[0107] Vertical force-tilt angle correlation (FAv): 0.92

[0108] Displacement-tilt angle correlation (DAv): 0.80

[0109] Time window T3:

[0110] Vertical force: 1600N, 1650N, 1700N

[0111] Displacement: 6.0mm, 6.5mm, 7.0mm

[0112] Tilt angle: 0.75°, 0.8°, 0.85°

[0113] Vertical force-displacement correlation (FDv): 0.98

[0114] Vertical force-tilt angle correlation (FAv): 0.95

[0115] Displacement-tilt angle correlation (DAv): 0.75

[0116] Time window T4:

[0117] Vertical force: 1700N, 1750N, 1800N

[0118] Displacement: 7.0mm, 7.5mm, 8.0mm

[0119] Tilt angle: 0.85°, 0.9°, 0.95°

[0120] Vertical force-displacement correlation (FDv): 0.99

[0121] Vertical force-tilt angle correlation (FAv): 0.97

[0122] Displacement-tilt angle correlation (DAv): 0.65

[0123] Time window T5:

[0124] Vertical force: 1800N, 1850N, 1900N

[0125] Displacement: 8.0mm, 8.5mm, 9.0mm

[0126] Tilt angle: 0.95°, 1.0°, 1.05°

[0127] Vertical force-displacement correlation (FDv): 0.99

[0128] Vertical force-tilt angle correlation (FAv): 0.98

[0129] Displacement-tilt angle correlation (DAv): 0.50

[0130] Afterwards, through data analysis, it was found that for the relationship between vertical force and displacement data (FDv), in each time window, the correlation between vertical force and displacement gradually approached, showing a linear relationship, indicating that as the pressure increased, the displacement increased more and more obviously, which is consistent with the phenomenon that the rigidity of the ladder decreased during plastic deformation. For the relationship between vertical force and tilt angle data (FAv), the correlation between vertical force and tilt angle also gradually approached, indicating that the relationship between the overall tilt angle change of the ladder and the applied vertical pressure increased, which may be because after plastic deformation, the structural deformation is more concentrated and significant. As for the relationship between displacement and tilt angle data (DAv), in the first few time windows, the correlation between displacement and tilt angle gradually decreased from 0.85 to 0.50. This means that although the displacement is increasing, the change in tilt angle no longer follows the increase in displacement. This may be a signal of local failure or material fatigue inside the ladder, causing the overall structure to no longer deform uniformly.

[0131] It can be seen that under normal conditions, the displacement and tilt angle should change synchronously with the vertical pressure, but when the ladder enters an abnormal state, local areas may begin to fail, resulting in a deviation in the relationship between the displacement data and the tilt angle. At the same time, the continued application of pressure causes the material to enter the plastic region, resulting in a gradual strengthening of the relationship between the vertical force and the displacement, and the vertical force and the tilt angle, because the overall structural rigidity is weakened, showing a linear change. The phenomenon of a decrease in the correlation between displacement and tilt angle indicates that the structure has begun to become unstable, some areas have lost their support capacity, and the change in the overall tilt angle is no longer consistent with the change in displacement, which marks the beginning of the anomaly.

[0132] In some embodiments, it is detected that the absolute value of the difference between FDv and FAv in a plurality of consecutive sliding time windows continues to decrease over time, and simultaneously it is detected that DAv continues to increase over time. The specific monitoring method is:

[0133] Implementation method 1: If it is not a large-scale assembly line production, or in an application environment where large-scale data parallel quadratic derivation can be avoided, the difference between FDv and FAv and DAv can be quadratically derivatized over time, and the absolute value of the difference between FDv and FAv is judged to continue to decrease over time and DAv to continue to increase over time according to the result of the quadratic derivation;

[0134] Implementation method 2: According to actual engineering experience, it is preferred to take 5 sliding time windows; calculate the absolute value of the difference between FDv and FAv corresponding to each sliding time window; if the absolute value of the difference between FDv and FAv corresponding to the first three sliding time windows is greater than the absolute value of the difference between FDv and FAv corresponding to the fourth sliding time window, start to judge whether the absolute value of the difference between FDv and FAv corresponding to the fourth sliding time window is greater than the absolute value of the difference between FDv and FAv corresponding to the fifth sliding time window; if the fourth is also greater than the fifth, the absolute value of the difference between FDv and FAv continues to decrease over time; and correspondingly, calculate the DAv corresponding to each sliding time window; if the DAv corresponding to the first three sliding time windows is less than or its mean is less than the DAv corresponding to the fourth sliding time window, then optionally judge whether the DAv corresponding to the fourth sliding time window is less than the DAv corresponding to the fifth sliding time window; if so, the DAv continues to increase over time.

[0135] In the production process of aluminum alloy ladders, it is necessary to find the point of application of pressure by the cylinder. This step is to accurately find the appropriate point of application so that the ladder can be repeatedly pressure tested at the point of application. However, the process of finding the point of application needs to be very careful, and this process is also very long and fragile, especially for some new product models that are very fragile and took a lot of time to produce. If you are not careful, you will use too much force and the ladder will be crushed all at once. If you use too little force, it will be very long and time-consuming. Therefore, it is necessary to have a method for locating the point of application of a ladder detection device as described above in the present invention, which can monitor the subtle state of the ladder point of application in the positioning process in real time, prevent minor problems, and prevent product damage, so as to help the equipment to achieve positioning of the point of application in ladder detection.

[0136] The system for locating the fulcrum point of a ladder detection device runs on any computing device such as a desktop computer, a laptop computer, a PDA or a cloud data center. The computing device includes: a processor, a memory and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps in the method for locating the fulcrum point of a ladder detection device are implemented. The executable system may include, but is not limited to, a processor, a memory, and a server cluster.

[0137] An embodiment of the present invention provides a system for locating a force point of a ladder detection device, such as Figure 2 As shown, a system for locating a fulcrum point of a ladder detection device in this embodiment comprises: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned method for locating a fulcrum point of a ladder detection device are implemented. The processor executes the computer program to run in the following system units:

[0138] The data acquisition unit is used to: measure the vertical force data applied by the cylinder in real time at the contact point between the cylinder and the ladder; monitor the displacement data of the cylinder in real time between the cylinder and the ladder; measure the strain data generated by the ladder after the force is applied in real time at the position where the ladder is subjected to force; and obtain the inclination angle data of the ladder in real time by measuring at each supporting point of the ladder;

[0139] A turning point monitoring unit is used to monitor the compressive turning point of the ladder according to the growth trend of the vertical force data and the strain data in the time direction;

[0140] The abnormality identification unit is used to identify abnormalities after the compression turning point by continuing to monitor the ladder, including the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the tilt angle data, and the relationship between the displacement data and the tilt angle data, so as to correct the abnormalities and continue the test.

[0141] Among them, in order to better unify the numerical linear relationship and probabilistic connection between physical quantities of different units of measurement, different physical quantities can be dimensionally processed.

[0142] Among them, preferably, all undefined variables in the present invention, if not clearly defined, can be manually set thresholds.

[0143] The system for locating the point of application of a ladder detection device can be run in computing devices such as desktop computers, laptop computers, PDAs, and cloud data centers. The system for locating the point of application of a ladder detection device includes, but is not limited to, a processor and a memory. Those skilled in the art can understand that the example is only an example of a method, system, and device for locating the point of application of a ladder detection device, and does not constitute a limitation on the method, system, and device for locating the point of application of a ladder detection device. It can include more or fewer components than the example, or a combination of certain components, or different components. For example, the system for locating the point of application of a ladder detection device can also include input and output devices, network access devices, buses, etc.

[0144] The present invention also provides an electronic device, a readable storage medium and a computer program product:

[0145] An electronic device comprises: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for locating the fulcrum of a ladder detection device and the methods of each step therein.

[0146] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause the computer to execute the method for locating the force point of a ladder detection device and the steps thereof.

[0147] A computer program product comprises a computer program. When the computer program is executed by a processor, the method for locating a force point of a ladder detection device and the methods for each step thereof are implemented.

[0148] Wherein, electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0149] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0150] The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0151] In the context of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0152] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0153] The systems and techniques described herein may be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), and the Internet.

[0154] A computer system may include clients and servers. Clients and servers are generally remote from each other and usually interact through a communication network. The relationship of client and server is generated by computer programs running on respective computers and having a client-server relationship to each other.

[0155] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete component gate circuits or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the system for positioning the focus point of the ladder detection device, and uses various interfaces and lines to connect the various sub-areas of the entire system for positioning the focus point of the ladder detection device.

[0156] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the method, system and device for locating the focus point of the ladder detection device by running or executing the computer program and / or module stored in the memory and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0157] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps recorded in the present disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document is not limited here.

[0158] The present invention provides a method, system and device for locating the force point of a ladder detection device, which can be used to measure the vertical force data applied by the cylinder in real time at the force point where the cylinder contacts the ladder; monitor the displacement data of the cylinder in real time between the cylinder and the ladder; measure the strain data generated by the ladder after being stressed in real time at the force-bearing part of the ladder; obtain the inclination angle data of the ladder in real time by measuring at each supporting point of the ladder; monitor the compression turning point of the ladder according to the growth trend of the vertical force data and the strain data in the time direction; after the compression turning point, continue to monitor the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the inclination angle data, and the relationship between the displacement data and the inclination angle data, identify the abnormality, correct the abnormality and continue the test. Not only does it improve the accuracy and safety of the positioning of the ladder force point, but it also greatly reduces the test time and cost through automatic control technology.

[0159] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for locating the force point of a ladder detection device, applying force to a ladder to be detected by a cylinder, and adjusting the force of the cylinder on the ladder, characterized in that: The method comprises: measuring the vertical force data applied by the cylinder in real time at the contact point between the cylinder and the ladder; monitoring the displacement data of the cylinder in real time between the cylinder and the ladder; measuring the strain data generated by the ladder after the force is applied in real time at the position where the ladder is applied; acquiring the inclination angle data of the ladder in real time by measuring at each supporting point of the ladder; monitoring the compression turning point of the ladder according to the growth trend of the vertical force data and the strain data in the time direction; continuing to monitor the ladder after the compression turning point, identifying anomalies through the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the inclination angle data, and the relationship between the displacement data and the inclination angle data, so as to correct the anomalies and continue testing; Among them, correcting the abnormality and continuing the test specifically includes: adjusting the position of the cylinder, or adjusting the height of the ladder, or adjusting the force of the cylinder on the ladder; Among them, after the compression turning point, the ladder continues to be monitored, and the abnormality is identified through the relationship between the vertical force data and the displacement data, the relationship between the vertical force data and the inclination angle data, and the relationship between the displacement data and the inclination angle data. The specific method is: after the compression turning point, the sliding time window sampling is used to monitor the vertical force data, displacement data and inclination angle data of multiple sliding time windows. If the numerical relationship between the vertical force data and the displacement data, and the numerical relationship between the vertical force data and the inclination angle data become closer and closer over time, and the numerical relationship between the displacement data and the inclination angle data deviates more and more over time, it is judged that the state of the ladder is abnormal.

2. A method for locating the force point of a ladder detection device according to claim 1, characterized in that: in, The vertical force applied by the cylinder is measured in real time by a multi-axis force sensor installed at the point where the cylinder contacts the ladder.

3. A method for locating the force point of a ladder detection device according to claim 1, characterized in that: in, The distance the cylinder moves is measured by a linear displacement sensor, which is mounted between the cylinder and the ladder.

4. A method for locating a force point of a ladder detection device according to claim 1, characterized in that: in, The stress and / or strain values ​​generated by the ladder after being subjected to force are measured by a strain gauge sensor. The strain gauge sensor is pasted on key parts of the ladder where force is applied, including the rungs and / or pedals. The strain gauge sensor can calculate the stress distribution by measuring the deformation of the ladder material; the inclination angle of the ladder on an uneven surface is measured by an angle sensor, which is installed at each supporting point of the ladder.

5. A method for locating a force point of a ladder detection device according to claim 1, characterized in that: According to the growth trend of vertical force data and strain data in the time direction, the method for monitoring the compression turning point of the ladder is: calculate the second-order derivative of the vertical force data on the ladder with time, calculate the second-order derivative of the strain data with time, and then select the smaller value between the second-order derivative of the vertical force data with time and the second-order derivative of the strain data with time as the turning point signal. The moment when the value of the turning point signal stops increasing is the compression turning point.

6. A method for locating a force point of a ladder detection device according to claim 1, characterized in that: in, According to the growth trend of vertical force data and strain data in the time direction, the method for monitoring the compression turning point of the ladder is: The value of the vertical force data corresponding to the current moment is obtained as the real-time vertical force value, and the value of the strain data corresponding to the current moment is obtained as the real-time strain value; the arithmetic mean of the values ​​of the vertical force data at each sampling moment before the current moment is calculated as the previous vertical force mean, and the arithmetic mean of the values ​​of the strain data at each sampling moment before the current moment is calculated as the previous strain mean; the difference between the real-time vertical force value and the previous vertical force mean is used as the previous vertical force distance, the difference between the real-time strain value and the previous strain mean is used as the previous strain distance, the ratio of the exponential value of the previous vertical force distance to the exponential value of the previous vertical force mean is used as the previous vertical force trend, and the ratio of the previous strain distance to the previous strain mean is used as the previous strain trend; according to the previous vertical force trend and the previous strain trend, the compression turning point of the ladder is monitored.

7. A system for locating the force point of a ladder detection device, characterized in that: The system for locating the fulcrum point of a ladder detection device runs on a desktop computer, a laptop computer or any computing device in a cloud data center. The computing device includes: a processor, a memory and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps in the method for locating the fulcrum point of a ladder detection device as described in any one of claims 1 to 6 are implemented.

8. An electronic device, comprising: at least one processor; and a memory communicatively coupled to the at least one processor; The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 6.

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