Method for acquiring pressure of ground push-out test cylinder of air source type push-out mechanism

Abstract

The invention provides a method for acquiring the pressure of a ground push-out test cylinder of an air source type push-out mechanism. The method comprises the following steps: step 1, installing a strain gauge and a displacement measurement mark; step 2, performing measurement in a mechanism push-out process on the basis of the step 1 to obtain a curve of strain changing along with time and a curve of displacement changing along with time; step 3, calculating a curve of cylinder pressure changing along with displacement, including: 3.1, calculating the pressure of the whole gas path after being pushed out in place; 3.2, acquiring a strain value after the in-place strain change curve along with time is stabilized according to the strain change curve along with time acquired in the step 2; 3.3, according to the results obtained in the step 3.1 and the step 3.2, obtaining a change curve of the cylinder pressure along with time; and 3.4, acquiring a change curve of the cylinder pressure along with the displacement according to the change curve of the cylinder pressure along with the time and the change curve of the displacement along with the time. The method is simple and insensitive to temperature and noise, and the test cost is effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of ground push-out test of a mechanism, and in particular relates to a method for obtaining the pressure of a cylinder in a ground push-out test of an air source type push-out mechanism. Background Art

[0002] In the ground pushing test of the air-source pushing mechanism, it is crucial to obtain the relationship between the cylinder pressure of the air-source pushing mechanism and the pushing displacement, which is crucial for the analysis of the push-resistance relationship of the mechanism and the selection and verification of the impact reduction components.

[0003] In the existing test technology, the gas circuit pressure is collected and recorded by designing a pressure sensor interface in the gas circuit, installing the pressure sensor and connecting the data acquisition recorder and other installation test methods. The existing pressure sensor is highly temperature sensitive, easily disturbed by external noise, and easily damaged under high-speed impact conditions. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To this end, the present invention provides a method for obtaining the cylinder pressure of a ground push-out test of an air source type push-out mechanism.

[0006] The technical solution of the present invention is as follows: a method for obtaining the pressure of a ground push-out test cylinder of an air source push-out mechanism is provided, the method comprising:

[0007] Step 1: Install the strain gauges and displacement measurement markers, including:

[0008] 1.1 Install a unidirectional strain gauge on the bracket where the cylinder is installed, and connect the strain gauge to the dynamic strain gauge;

[0009] 1.2 Install the displacement identification mark of the high-speed photography equipment on the ejection mechanism;

[0010] Step 2: Based on step 1, measure the mechanism during its pushing out process to obtain a strain-time curve and a displacement-time curve;

[0011] Step 3: Calculate the cylinder pressure versus displacement curve, including:

[0012] 3.1 Calculate the pressure P of the entire gas path after it is pushed into place;

[0013] 3.2 According to the strain variation with time curve obtained in step 2, obtain the strain value ε after the strain variation with time curve is stabilized;

[0014] 3.3 Obtain a curve of cylinder pressure changing with time based on the results obtained in step 3.1 and step 3.2;

[0015] 3.4 Obtain the cylinder pressure versus displacement variation curve based on the cylinder pressure versus time variation curve and the displacement versus time variation curve.

[0016] Furthermore, the strain gauge is installed in a direction along which the surface of the bracket bears tensile stress.

[0017] Furthermore, the step 2 specifically includes:

[0018] 2.1 Use a dynamic strain gauge to measure and store the strain during the mechanism's push-out process, and obtain a strain-time curve;

[0019] 2.2 Use high-speed photography equipment to measure and store the displacement of the push-out structure during the push-out process of the mechanism, and obtain the displacement change curve over time.

[0020] Furthermore, the acquisition frequencies of the dynamic strain gauge and the high-speed photography equipment are both 1000 Hz.

[0021] Furthermore, step 2.1 also includes: filtering the strain-time variation curve.

[0022] Furthermore, the pressure P of the entire gas path after being pushed into place is calculated by the following formula:

[0023]

[0024] Among them, n is the polynomial index, which is 1.2; P0 is the initial pressure of the high-pressure gas cylinder at room temperature, V0 is the volume of the high-pressure gas cylinder, V1 is the volume of the gas pipeline, and V2 is the volume of the cylinder cavity after the cylinder is pushed into place.

[0025] Furthermore, the cylinder pressure variation curve over time is obtained according to the results obtained in step 3.1 and step 3.2 in the following manner:

[0026] According to the linear relationship between strain and cylinder pressure, Multiplying by the filtered strain value, we can obtain the cylinder pressure change curve over time.

[0027] The above technical scheme proposes a method for calculating the cylinder pressure of a ground pushing test of an air-source pushing mechanism based on the existing design parameters, strain and displacement measurement data. There is no need to design a pressure sensor interface, purchase a pressure sensor and an acquisition recorder. The cylinder pressure versus displacement curve can be obtained based on the existing design parameters, strain and displacement measurement data. The method is insensitive to temperature and noise and effectively reduces the test cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 Schematic diagram of the ejection mechanism and the installation position of the unidirectional strain gauge. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0032] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0033] like Figure 1As shown, in one embodiment of the present invention, a method for obtaining the cylinder pressure of a ground push-out test of an air source type push-out mechanism is provided, the method comprising:

[0034] Step 1: Install the strain gauges and displacement measurement markers, including:

[0035] 1.1 Install a unidirectional strain gauge 3 on the bracket 2 on which the cylinder 1 is installed. The strain gauge 3 is installed in the direction along which the surface of the bracket bears tensile stress, and the strain gauge 3 is connected to the dynamic strain gauge;

[0036] 1.2 Install the displacement identification mark of the high-speed photography equipment on the ejection mechanism;

[0037] Step 2: Based on step 1, measure the mechanism during its pushing out process to obtain a strain-time curve and a displacement-time curve;

[0038] Step 3: Calculate the cylinder pressure versus displacement curve, including:

[0039] 3.1 Calculate the pressure P of the entire gas path after it is pushed into place;

[0040] 3.2 According to the strain variation with time curve obtained in step 2, obtain the strain value ε after the strain variation with time curve is stabilized;

[0041] 3.3 Obtain a curve of cylinder pressure changing with time based on the results obtained in step 3.1 and step 3.2;

[0042] 3.4 Obtain the cylinder pressure versus displacement variation curve based on the cylinder pressure versus time variation curve and the displacement versus time variation curve.

[0043] That is, if Figure 1 The specific structure of the push-out mechanism shown is well-known in the art and will not be described in detail here. The embodiment of the present invention is to install strain gauges and displacement measurement marks on the basis of the mechanism to obtain the push-out test cylinder pressure.

[0044] In the embodiment of the present invention, the initial pressure P0 of the high-pressure gas cylinder at room temperature, the volume V0 of the high-pressure gas cylinder, the volume V1 of the gas pipeline, and the volume V2 of the cylinder cavity after the cylinder is pushed into place can be queried in advance according to the design document, thereby calculating the pressure of the gas circuit.

[0045] It can be seen that the embodiment of the present invention proposes a method for calculating the cylinder pressure of a ground pushing test of an air-source pushing mechanism based on existing design parameters, strain, and displacement measurement data. There is no need to design a pressure sensor interface, purchase a pressure sensor, and an acquisition recorder. The cylinder pressure versus displacement curve can be obtained based on the existing design parameters, strain, and displacement measurement data. The method is insensitive to temperature and noise, and effectively reduces the test cost.

[0046] In the above embodiment, the step 2 specifically includes:

[0047] 2.1 Use a dynamic strain gauge to measure and store the strain during the mechanism's push-out process, and obtain a strain-time curve;

[0048] 2.2 Use high-speed photography equipment to measure and store the displacement of the push-out structure during the push-out process of the mechanism, and obtain the displacement change curve over time.

[0049] Wherein, the acquisition frequencies of the dynamic strain gauge and the high-speed photography equipment are both 1000 Hz.

[0050] Preferably, step 2.1 further comprises: filtering the strain-time variation curve.

[0051] In the above embodiment, the pressure P of the entire gas path after the push-out is in place is calculated by the following formula:

[0052]

[0053] Among them, n is the polynomial index, which is 1.2; P0 is the initial pressure of the high-pressure gas cylinder at room temperature, V0 is the volume of the high-pressure gas cylinder, V1 is the volume of the gas pipeline, and V2 is the volume of the cylinder cavity after the cylinder is pushed into place.

[0054] In the above embodiment, the cylinder pressure variation curve over time is obtained according to the results obtained in step 3.1 and step 3.2 in the following manner:

[0055] According to the linear relationship between strain and cylinder pressure, Multiplying by the filtered strain value, we can obtain the cylinder pressure change curve over time.

[0056] In order to further understand the method of the embodiment of the present invention, a specific embodiment is described in detail below:

[0057] An embodiment of the present invention provides a method for obtaining the cylinder pressure of a ground push-out test of an air source type push-out mechanism, the method specifically comprising:

[0058] Step 1: Obtain calculation parameters: According to the design documents, query the initial pressure P0 of the high-pressure gas cylinder at room temperature, the volume V0 of the high-pressure gas cylinder, the volume V1 of the gas pipeline, and the volume V2 of the cylinder cavity after the cylinder is pushed into place;

[0059] Step 2: Install the strain and displacement measurement system:

[0060] 2.1) Install the unidirectional strain gauge 3 on the bracket 2 where the cylinder 3 is installed. The installation position and direction of the strain gauge 3 are as follows: Figure 1 As shown, the strain gauge is connected to the dynamic strain gauge;

[0061] 2.2) Install high-speed photography equipment and install displacement identification marks of high-speed photography equipment on the pushed-out structure;

[0062] Step 3: Measure and obtain the strain-time curve and displacement-time curve:

[0063] 3.1) Using a dynamic strain gauge with a collection frequency of 1000 Hz, the strain during the mechanism push-out process is measured and stored to obtain a strain-time curve;

[0064] 3.2) Filter the strain-time curve to eliminate high-frequency oscillations in individual time periods and obtain the filtered strain-time curve;

[0065] 3.3) Using high-speed photography equipment with a collection frequency of 1000 Hz, the displacement of the push-out structure during the push-out process of the mechanism is measured and stored to obtain a displacement versus time curve;

[0066] Step 4: Calculate the cylinder pressure versus displacement curve:

[0067] 4.1) According to the multivariable state change process equation of ideal gas, calculate the pressure P of the entire gas path after the push is in place, Among them, when studying the cylinder motion and piston motion speed, the polytropic index n is taken as 1.2;

[0068] 4.2) According to the filtered strain-time curve, read the strain value ε after the strain-time curve is stabilized;

[0069] 4.3) According to the linear relationship between strain and cylinder pressure, Multiplying by the filtered strain value, we can obtain the cylinder pressure variation curve over time;

[0070] 4.4) Based on the cylinder pressure variation curve and the displacement variation curve, the cylinder pressure variation curve is calculated and derived.

[0071] Features described and / or illustrated above for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or used in place of features in other embodiments.

[0072] It should be emphasized that the term "include / comprises" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps, components or combinations thereof.

[0073] The above method of the present invention can be implemented by hardware, or by hardware combined with software. The present invention relates to such a computer-readable program, which, when executed by a logic component, enables the logic component to implement the above-mentioned device or component, or enables the logic component to implement the above-mentioned various methods or steps. The present invention also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0074] The many features and advantages of these embodiments are apparent from this detailed description, and thus the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not intended that the embodiments of the invention be limited to the exact construction and operation illustrated and described, but rather all suitable modifications and equivalents falling within the scope thereof are intended to be covered.

[0075] Parts of the present invention that are not described in detail are well known to those skilled in the art.

Claims

1. A method for obtaining the cylinder pressure of a ground push-out test of an air source push-out mechanism, characterized in that: The method comprises: Step 1: Install the strain gauges and displacement measurement markers, including: 1.1 Install a unidirectional strain gauge on the bracket where the cylinder is installed, and connect the strain gauge to the dynamic strain gauge; 1.2 Install the displacement identification mark of the high-speed photography equipment on the ejection mechanism; Step 2: Based on step 1, measure the mechanism during its pushing out process to obtain a strain-time curve and a displacement-time curve; Step 3: Calculate the cylinder pressure versus displacement curve, including: 3.1 Calculate the pressure P of the entire gas path after it is pushed into place; 3.2 According to the strain variation with time curve obtained in step 2, obtain the strain value ε after the strain variation with time curve is stabilized; 3.3 Obtain a curve of cylinder pressure changing with time based on the results obtained in step 3.1 and step 3.2; 3.4 Obtain the cylinder pressure versus displacement variation curve based on the cylinder pressure versus time variation curve and the displacement versus time variation curve.

2. The method for obtaining the cylinder pressure of a ground push-out test of an air source push-out mechanism according to claim 1, characterized in that: The strain gauge is installed in the direction along which the bracket surface bears tensile stress.

3. A method for obtaining the cylinder pressure of a ground push-out test of an air source push-out mechanism according to claim 1-2, characterized in that: The specific details of step 2 include: 2.1 Use a dynamic strain gauge to measure and store the strain during the mechanism's push-out process to obtain a strain-time curve; 2.2 Use high-speed photography equipment to measure and store the displacement of the push-out structure during the push-out process of the mechanism, and obtain the displacement change curve over time.

4. A method for obtaining the cylinder pressure of a ground push-out test of an air source push-out mechanism according to claim 3, characterized in that: The acquisition frequencies of the dynamic strain gauge and the high-speed photography equipment are both 1000 Hz.

5. The method for obtaining the cylinder pressure of a ground push-out test of an air source push-out mechanism according to claim 3 is characterized in that: Step 2.1 also includes: filtering the strain-time variation curve.

6. The method for obtaining the cylinder pressure of a ground push-out test of an air source push-out mechanism according to claim 1, characterized in that: The pressure P of the entire gas path after it is pushed into place is calculated by the following formula: Among them, n is the polynomial index, which is 1.2; P0 is the initial pressure of the high-pressure gas cylinder at room temperature, V0 is the volume of the high-pressure gas cylinder, V1 is the volume of the gas pipeline, and V2 is the volume of the cylinder cavity after the cylinder is pushed into place.

7. A method for obtaining the cylinder pressure of a ground push-out test of an air source push-out mechanism according to claim 6, characterized in that: The cylinder pressure variation curve over time is obtained according to the results obtained in step 3.1 and step 3.2 in the following way: According to the linear relationship between strain and cylinder pressure, Multiplying by the filtered strain value, we can obtain the cylinder pressure change curve over time.

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