Hydraulic cylinder friction force test servo module and system

Abstract

The utility model discloses a hydraulic cylinder friction force test servo module and system, and the module comprises an execution oil path which is connected with an oil supply source and a tested element, an oil return path which is connected with the tested element and an oil tank, and a displacement sensor which is arranged on the tested element. The execution oil way comprises a first oil way and a second oil way which are respectively connected with a rodless cavity and a rod cavity of a tested element, the flow control unit comprises a first direction flow control valve arranged on the first oil way and a second direction flow control valve arranged on the second oil way, and the module further comprises a pressure control unit. The pressure control unit is used for compensating the pressure drop in the execution oil way, adjusting the pressure in the execution oil way to be within the test pressure range and stabilizing the back pressure during the test. The direction flow control valve is directly connected with a tested element, response is fast, displacement feedback is output to the tested cylinder in real time through the displacement sensor, and sinusoidal motion and constant-speed motion control over the tested cylinder can be conveniently achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to hydraulic test technical field especially relates to a kind of hydraulic cylinder friction test servo module and system. BACKGROUND

[0002] With the improvement of the control accuracy of hydraulic servo system, the friction of hydraulic cylinder has become an important problem that cannot be ignored. The nonlinear friction of hydraulic cylinder has a great influence on the static and dynamic characteristics of the system, mainly manifested in the crawling phenomenon at low speed, the waveform distortion phenomenon at zero speed, the generation of static dead zone and dynamic dead zone, and even the limit cycle oscillation phenomenon. In order to better describe the friction of hydraulic cylinder, it is necessary to study the accurate test of hydraulic cylinder friction and identify the friction parameters.

[0003] Patent document CN101441122A provides a kind of servo hydraulic cylinder no-load starting friction test system and test method, wherein the oil outlet of oil pump is communicated with the P port of electro-hydraulic servo valve through filter, the A port or B port of electro-hydraulic servo valve is communicated with the A port of throttle valve, the pipeline connected with the A port or B port of electro-hydraulic servo valve and the A port of throttle valve is communicated with the rodless cavity of the hydraulic cylinder to be tested. Displacement sensor is arranged on the piston rod of the hydraulic cylinder to be tested, and the displacement sensor is electrically connected with the A / D port of data acquisition card; pressure sensor is installed on the pipeline connected with the A port or B port of electro-hydraulic servo valve and the A port of throttle valve, and the pressure sensor is electrically connected with the A / D port of data acquisition card; data acquisition card and computer aided test software are installed in computer.

[0004] However, in the technical solution of the above patent, pressure drop is inevitably generated when oil flows through electro-hydraulic servo valve and throttle valve, but effective compensation mechanism is not set, which may lead to instability of hydraulic cylinder input pressure, thereby affecting the precision of friction test. UTILITY MODEL CONTENT

[0005] Therefore, it is necessary to provide a kind of hydraulic cylinder friction test servo module and system with pressure drop compensation for the problem that the above technical solution cannot compensate pressure drop.

[0006] The application provides a kind of hydraulic cylinder friction test servo module, including the execution oil circuit connected with oil supply source and the element to be tested, the back oil circuit connected with the element to be tested and oil tank, and the displacement sensor arranged on the element to be tested, the execution oil circuit includes the first oil circuit and the second oil circuit connected with the rodless cavity and the rod cavity of the element to be tested respectively,

[0007] The test device further comprises a flow control unit, the flow control unit comprises a first directional flow control valve arranged on the first oil passage and a second directional flow control valve arranged on the second oil passage, an A1 oil port of the first directional flow control valve is connected to a rodless chamber of the test element through a Pa oil port of the test element, a P1 oil port of the first directional flow control valve is connected to an oil supply source, an A oil port of the second directional flow control valve is connected to a rod chamber of the test element through a Pb oil port of the test element, and a P2 oil port of the second directional flow control valve is connected to the oil supply source.

[0008] The test device further comprises a pressure control unit, the oil return passage comprises a third oil passage and a fourth oil passage, one end of the third oil passage is connected to the oil tank, and the other end is arranged between the A1 oil port of the first directional flow control valve and the Pa oil port of the test element, one end of the fourth oil passage is connected to the oil tank, and the other end is arranged between the A2 oil port of the second directional flow control valve and the Pb oil port of the test element, the pressure control unit comprises a first pressure control valve arranged on the third oil passage and a second pressure control valve arranged on the fourth oil passage, and the pressure control unit is used to compensate for pressure drop in the execution oil passage, adjust the pressure in the execution oil passage to the test pressure range, and stabilize the back pressure during the test.

[0009] Optionally, the execution oil passage further comprises a converging oil passage, one end of the converging oil passage is connected to the P oil port of the first directional flow control valve and the P2 oil port of the second directional flow control valve, and the other end is connected to the oil supply source.

[0010] Optionally, the pressure control unit further comprises a first pressure sensor, the first pressure sensor is arranged on the converging oil passage and is used to detect and upload the oil pressure input by the oil supply source.

[0011] Optionally, the pressure control unit further comprises a second pressure sensor and a third pressure sensor, the second pressure sensor is arranged between the A1 oil port of the first directional flow control valve and the Pa oil port of the test element, and the third pressure sensor is arranged between the A2 oil port of the second directional flow control valve and the Pb oil port of the test element, and the second pressure sensor and the third pressure sensor are used to detect and upload the oil pressure in the pipeline of the first oil passage and the pipeline of the second oil passage.

[0012] Optionally, the pressure control unit further comprises a first pressure gauge, the first pressure gauge is arranged on the converging oil passage and is used to measure the oil pressure input by the oil supply source.

[0013] Optionally, the pressure control unit further comprises a second pressure gauge and a third pressure gauge, the second pressure gauge is arranged between the A1 oil port of the first direction flow control valve and the Pa oil port of the test element, the third pressure gauge is arranged between the A2 oil port of the second direction flow control valve and the Pb oil port of the test element, and the second pressure gauge and the third pressure gauge are used to measure the oil pressure in the pipeline of the first oil circuit and the pipeline of the second oil circuit.

[0014] Optionally, the pressure control unit further comprises a first pressure gauge cut-off valve, the first pressure gauge cut-off valve is arranged on the first pressure gauge and is used to control the opening and closing of the first pressure gauge measuring pipeline.

[0015] Optionally, the pressure control unit further comprises a second pressure gauge cut-off valve and a third pressure gauge cut-off valve, the second pressure gauge cut-off valve is arranged on the second pressure gauge, the third pressure gauge cut-off valve is arranged on the third pressure gauge, and the second pressure gauge cut-off valve and the third pressure gauge cut-off valve are used to control the opening and closing of the second pressure gauge measuring pipeline and the third pressure gauge measuring pipeline.

[0016] Optionally, the oil filter is arranged on the converging oil circuit and is used to filter the pressure oil delivered by the oil supply source.

[0017] The application further provides a hydraulic cylinder friction force test system, which comprises the hydraulic cylinder friction force test servo module, an oil tank and an oil supply device, the oil supply device is used to extract the oil in the oil tank and deliver the oil to the execution oil circuit, and the oil tank is further connected with the return oil circuit.

[0018] Compared with the prior art, the technical scheme provided by the application has the following beneficial effects:

[0019] The first direction flow control valve and the second direction flow control valve of the hydraulic cylinder friction force test servo module are directly connected with the rodless cavity and the rod cavity of the test element, the oil circuit design path is simplified, the system response speed and the control accuracy are improved, and in particular, in the control of continuous sinusoidal motion or uniform motion, more stable and rapid feedback control can be realized. The first pressure control valve and the second pressure control valve arranged on the third oil circuit and the fourth oil circuit can automatically compensate the pressure drop in the execution oil circuit caused by the oil flowing through the direction flow control valve, ensure that the pressure in the test process is maintained within the set range, and thus the reliability of the friction force measurement is improved. The return oil circuit connects the execution oil circuit and the oil tank through the third oil circuit and the fourth oil circuit and is adjusted by the pressure control unit, which can stabilize the back pressure in the test process, so as to ensure that the pressure of the test element is stable during reciprocating motion and avoid test data errors caused by back pressure fluctuation. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A hydraulic cylinder friction test servo module structure diagram is provided for an embodiment of the present application.

[0021] Reference signs:

[0022] 1 - test element; 2 - displacement sensor; 3 - first direction flow control valve; 4 - second direction flow control valve; 5 - first pressure control valve; 6 - second pressure control valve; 7 - first pressure sensor; 8 - second pressure sensor; 9 - third pressure sensor; 10 - first pressure gauge; 11 - second pressure gauge; 12 - third pressure gauge; 13 - first pressure gauge stop valve; 14 - second pressure gauge stop valve; 15 - third pressure gauge stop valve; 16 - oil filter. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purpose, features and advantages of the present application more apparent, obvious and understandable, the specific embodiments of the present application will be described in detail below with reference to the drawings. In the following description, a large number of specific details are set forth in order to facilitate a full understanding of the present application. However, the present application can be implemented in many different ways other than those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0024] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0025] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0026] In the utility model, unless another definite provision and limitation, the terms "mount", "link", "connect", "fix" and so on should do the broad sense understanding, for example, can be fixed connection, also can be detachable connection, or be integrated;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can be indirectly connected through the intermediate medium, can be the communication of two elements or the interaction of two elements, unless another definite limitation.For the ordinary skilled person in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0027] In the utility model, unless another definite provision and limitation, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium.Moreover, the first feature "over", "above" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature.The first feature "under", "below" and "on" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0028] It should be noted that when an element is referred to as "fixed to" or "provided on" another element, it can be directly on the other element or there can be a middle element.When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be a middle element.The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0029] Referring to Figure 1 The utility model discloses an embodiment provides a kind of hydraulic cylinder friction force test servo module, including the execution oil circuit of connecting oil supply source and test element 1, connecting the oil return oil circuit of test element 1 and oil tank, and setting displacement sensor 2 on test element 1, the execution oil circuit includes the first oil circuit and second oil circuit respectively connecting the rodless cavity and rod cavity of test element 1;

[0030] Further comprising a flow control unit, the flow control unit includes a first directional flow control valve 3 disposed on the first oil circuit and a second directional flow control valve 4 disposed on the second oil circuit, the A1 oil port of the first directional flow control valve 3 is connected to the rodless cavity of the test element 1 through the Pa oil port of the test element 1, the P1 oil port of the first directional flow control valve 3 is connected to the oil supply source, the A2 oil port of the second directional flow control valve 4 is connected to the rod cavity of the test element 1 through the Pb oil port of the test element 1, and the P2 oil port of the second directional flow control valve 4 is connected to the oil supply source.

[0031] The pressure control unit is further included, the oil return oil path includes a third oil path and a fourth oil path, one end of the third oil path is connected with the oil tank, the other end is arranged between the A1 oil port of the first direction flow control valve and the Pa oil port of the test element 1, one end of the fourth oil path is connected with the oil tank, the other end is arranged between the A2 oil port of the second direction flow control valve and the Pb oil port of the test element 1, the pressure control unit includes a first pressure control valve 5 arranged on the third oil path and a second pressure control valve 6 arranged on the fourth oil path, the pressure control unit is used for compensating the pressure drop in the execution oil path, adjusting the pressure in the execution oil path to the test pressure range and stabilizing the back pressure during the test.

[0032] In the implementation, when the first direction flow control valve 3 is opened and the second direction flow control valve 4 is closed, the pressure oil of the oil supply source enters the A1 oil port through the P1 oil port of the first direction flow control valve 3, and then is transported to the rodless cavity of the test element 1 along the first oil path, and pushes the piston rod to move right through the Pa oil port. At the same time, the first pressure control valve 5 is closed to prevent the oil from flowing, and the second pressure control valve 6 is opened to allow the compressed oil in the rod cavity to flow into the second oil path through the Pb oil port and then flow into the fourth oil path, and then overflow through the second pressure control valve 6 and flow back to the oil tank through the Tb oil port.

[0033] When the second direction flow control valve 4 is opened and the first direction flow control valve 3 is closed, the pressure oil of the oil supply source enters the A2 oil port through the P2 oil port of the second direction flow control valve 4, and then is transported to the rod cavity of the test element 1 along the second oil path, and pushes the piston rod to move left through the Pb oil port. At this time, the second pressure control valve 6 is closed to prevent the oil from flowing, and the first pressure control valve 5 is opened to allow the compressed oil in the rodless cavity to flow into the first oil path through the Pa oil port and then flow into the third oil path, and then overflow through the first pressure control valve 5 and flow back to the oil tank through the Ta oil port.

[0034] Specifically in the embodiment, the first direction flow control valve 3 and the second direction flow control valve 4 are electrically modulated direction flow control valves, and the first pressure control valve 5 and the second pressure control valve 6 are electrically modulated pressure control valves, specifically proportional overflow valves or servo overflow valves. The combination of the electrically modulated direction flow control valve and the proportional overflow valve makes the embodiment have higher precision and response speed in the control of flow and pressure. In the test process, the flow and the back pressure are adjusted in real time through the electrically modulated valve, which not only ensures the accuracy of the sinusoidal motion or uniform motion of the piston of the test element 1, but also significantly improves the stability and reliability of the friction test data. This design can well meet the strict requirements of the hydraulic cylinder friction test on the dynamic performance and pressure control.

[0035] In this embodiment, the first direction flow control valve 3 and the second direction flow control valve 4 in the embodiment are directly connected with the rodless cavity and the rod cavity of the test element 1, which simplifies the oil path design path, thereby improving the system response speed and control accuracy, especially in the control of sinusoidal motion or uniform motion, more stable and rapid feedback control can be realized. By setting the first pressure control valve 5 and the second pressure control valve 6 on the third oil path and the fourth oil path, the pressure drop in the execution oil path caused by the oil flowing through the direction flow control valve can be automatically compensated, ensuring that the pressure in the test process is maintained within the set range, thereby improving the accuracy of the friction force measurement. The return oil path connects the execution oil path and the oil tank through the third oil path and the fourth oil path, and is adjusted by the pressure control unit, which can stabilize the back pressure in the test process, thereby ensuring that the pressure of the test element 1 is stable during reciprocating motion, avoiding test data errors caused by back pressure fluctuations.

[0036] Referring to Figure 1 The hydraulic cylinder friction test servo module provided by the embodiment further comprises a converging oil path, one end of the converging oil path is connected with the P1 oil port of the first direction flow control valve 3 and the P2 oil port of the second direction flow control valve 4, and the other end is connected with the oil supply source.

[0037] In this embodiment, the design of the converging oil path centralizes the oil supply path, which can effectively improve the oil supply efficiency and ensure the uniformity of oil supply of the first oil path and the second oil path, simplifying the oil path structure design. The multiple oil supply paths are integrated into one centralized oil supply pipeline, reducing the complexity of pipeline arrangement, improving the integration level of the servo module, making it more compact and convenient to install and maintain. In addition, as the central hub of the oil supply path, the converging oil path effectively avoids the pressure fluctuation interference between multiple independent oil supply paths, further improves the stability of the input pressure of the direction flow control valve, and enhances the operation reliability of the system during the test. Under different test conditions, the converging oil path does not need to adjust the oil supply path, ensuring the efficiency and stability of the hydraulic cylinder friction test.

[0038] Referring to Figure 1 The pressure control unit of the hydraulic cylinder friction test servo module provided by the embodiment further comprises a first pressure sensor 7, which is arranged on the converging oil path and used for detecting and uploading the oil pressure input by the oil supply source. By arranging the first pressure sensor 7, the pressure state of the oil supply source can be dynamically monitored, and accurate input pressure data can be provided for the pressure control unit, ensuring the accuracy of the execution oil path pressure regulation. When the input pressure of the oil supply source abnormally fluctuates, the first pressure sensor 7 can collect data in time and upload it to the control device, so as to adjust the output parameters of the pressure control valve, thereby avoiding the influence of abnormal oil supply pressure on the test accuracy and stability of the hydraulic cylinder.

[0039] Referring to Figure 1The hydraulic cylinder friction test servo module provided by the embodiment, the pressure control unit further comprises a second pressure sensor 8 and a third pressure sensor 9, the second pressure sensor 8 is arranged between the A1 oil port of the first direction flow control valve and the Pa oil port of the test element 1, the third pressure sensor 9 is arranged between the A2 oil port of the second direction flow control valve and the Pb oil port of the test element 1, and the second pressure sensor 8 and the third pressure sensor 9 are used for detecting and uploading the oil pressure in the pipeline of the first oil circuit and the pipeline of the second oil circuit.

[0040] The arrangement of the second pressure sensor 8 and the third pressure sensor 9 enables accurate monitoring of the pressure state of the pipeline of the first oil circuit and the pipeline of the second oil circuit during the test, and uploading of the collected pressure data to the control device. This design provides complete feedback information for the pressure control unit, and can better assist the control device in adjusting the pressure, so that the input pressure of the test hydraulic cylinder during the test is always maintained within the set range.

[0041] Referring to Figure 1 The hydraulic cylinder friction test servo module provided by the embodiment, the pressure control unit further comprises a first pressure gauge 10, the first pressure gauge 10 is arranged on the converging oil circuit, and is used for measuring the oil pressure input by the oil supply source.

[0042] Referring to Figure 1 The hydraulic cylinder friction test servo module provided by the embodiment, the pressure control unit further comprises a second pressure gauge 11 and a third pressure gauge 12, the second pressure gauge 11 is arranged between the A1 oil port of the first direction flow control valve and the Pa oil port of the test element 1, the third pressure gauge 12 is arranged between the A2 oil port of the second direction flow control valve and the Pb oil port of the test element 1, and the second pressure gauge 11 and the third pressure gauge 12 are used for measuring the oil pressure in the pipeline of the first oil circuit and the pipeline of the second oil circuit.

[0043] The hydraulic cylinder friction test servo module provided by the embodiment, the pressure control unit further comprises a first pressure gauge cutoff valve 13, the first pressure gauge cutoff valve 13 is arranged on the first pressure gauge 10, and is used for controlling the opening and closing of the measurement pipeline of the first pressure gauge 10.

[0044] Referring to Figure 1 The hydraulic cylinder friction test servo module provided by the embodiment, the pressure control unit further comprises a second pressure gauge cutoff valve 14 and a third pressure gauge cutoff valve 15, the second pressure gauge cutoff valve 14 is arranged on the second pressure gauge 11, the third pressure gauge cutoff valve 15 is arranged on the third pressure gauge 12, and the second pressure gauge cutoff valve 14 and the third pressure gauge cutoff valve 15 are used for controlling the opening and closing of the measurement pipeline of the second pressure gauge 11 and the third pressure gauge 12.

[0045] In order to improve the safety and service life of the pressure measuring system, the first pressure gauge cutoff valve 13 is arranged on the first pressure gauge 10 to control the opening and closing of the measuring pipeline of the first pressure gauge 10. Similarly, the second pressure gauge 11 and the third pressure gauge 12 are respectively provided with the second pressure gauge cutoff valve 14 and the third pressure gauge cutoff valve 15 to control the opening and closing of the measuring pipeline. The design of the cutoff valves can cut off the measuring pipeline when the pressure gauge does not need to work, so as to protect the pressure gauge from the damage caused by high pressure impact or long-term use, thereby prolonging the service life of the system.

[0046] Referring to Figure 1 The hydraulic cylinder friction test servo module also comprises an oil filter 16 arranged on the converging oil path and used for filtering the pressure oil delivered by the oil supply source. By additionally arranging the oil filter 16 in the converging oil path, the impurities and particles in the oil supply source can be effectively removed, so that the oil entering the execution oil path and the pressure control unit has high cleanliness. The arrangement of the oil filter 16 can not only protect the key elements (such as the directional flow control valve, the pressure control valve and the tested hydraulic cylinder) in the hydraulic system from the wear and blockage caused by the impurities in the oil, but also can reduce the risk of system failure caused by the impurities, thereby significantly improving the reliability and service life of the servo module.

[0047] An embodiment of the utility model further provides a kind of hydraulic cylinder friction test system, comprising the hydraulic cylinder friction test servo module described above, still comprising oil tank and oil supply device, oil supply device is used to extract the oil in oil tank and is delivered to execution oil path, oil tank is also connected with return oil path.

[0048] In the embodiment, after the friction test starts, the control device of the test system controls the spool of the first electric modulation directional flow control valve to act, so that the pressure oil of the oil supply source enters the A1 oil port through the P1 oil port of the first electric modulation directional flow control valve 3 and is delivered to the rodless cavity of the tested element 1 along the first oil path, and the pressure and flow are input through the Pa oil port to push the piston of the tested element 1 to move to the right. In combination with the real-time displacement signal collected by the displacement sensor 2, the control device realizes the sinusoidal motion or uniform motion of the piston of the tested element 1. At the same time, the control device controls the second electric modulation pressure control valve to open, so as to maintain the back pressure of the rod cavity of the tested element 1 stable and ensure that the pressure is maintained within the set range. In this process, the second pressure sensor 8 and the third pressure sensor 9 collect the pressure data of the rodless cavity and the rod cavity respectively, and the control device of the test system calculates the friction value according to the collected data and outputs the friction curve.

[0049] When the piston of the test element 1 moves to the rightmost limit position, the control device of the test system switches the control of the valve core of the second electric modulation direction flow control valve, so that the pressure oil of the oil supply source enters the A2 oil port through the P2 oil port of the second electric modulation direction flow control valve, and is delivered to the rod cavity of the test element 1 along the second oil path, and the pressure and flow are input through the Pb oil port, and the piston is pushed to move to the left. Combined with the real-time displacement signal collected by the displacement sensor 2, the control device also realizes the sinusoidal motion or uniform motion of the piston. At the same time, the control device controls the first electric modulation pressure control valve to open, so as to maintain the back pressure of the rodless cavity stable, and ensure that the pressure of the rodless cavity is in the set range. In this process, the second pressure sensor 8 and the third pressure sensor 9 continue to collect the pressure data of the rodless cavity and the rod cavity respectively, and the control device of the test system calculates the friction value according to the collected data and outputs the friction curve.

[0050] Through the cooperation of the electric modulation direction flow control valve and the electric modulation pressure control valve, the test system can accurately control the reciprocating motion of the piston and the oil path pressure, realize efficient and accurate friction force test and data output.

[0051] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, it should be considered that it is within the scope of the present application.

[0052] The above-described embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A hydraulic cylinder friction test servo module, comprising an execution oil path connecting an oil supply source and a test element (1), a return oil path connecting the test element (1) and an oil tank, and a displacement sensor (2) arranged on the test element (1), the execution oil path comprising a first oil path and a second oil path respectively connecting a rodless cavity and a rod cavity of the test element (1), characterized in that, further comprising a flow control unit, the flow control unit comprising a first direction flow control valve (3) arranged on the first oil path and a second direction flow control valve (4) arranged on the second oil path, an A1 oil port of the first direction flow control valve (3) being connected with the rodless cavity of the test element (1) through a Pa oil port of the test element (1), a P1 oil port of the first direction flow control valve (3) being connected with the oil supply source, an A2 oil port of the second direction flow control valve (4) being connected with the rod cavity of the test element (1) through a Pb oil port of the test element (1), and a P2 oil port of the second direction flow control valve (4) being connected with the oil supply source; further comprising a pressure control unit, the return oil path comprising a third oil path and a fourth oil path, one end of the third oil path being connected with the oil tank, the other end being arranged between the A1 oil port of the first direction flow control valve (3) and the Pa oil port of the test element (1), one end of the fourth oil path being connected with the oil tank, the other end being arranged between the A2 oil port of the second direction flow control valve (4) and the Pb oil port of the test element (1), the pressure control unit comprising a first pressure control valve (5) arranged on the third oil path and a second pressure control valve (6) arranged on the fourth oil path, the pressure control unit being used for compensating pressure drop in the execution oil path, adjusting pressure in the execution oil path to a test pressure range, and stabilizing back pressure during the test. the execution oil path further comprising a converging oil path, one end of the converging oil path being connected with the P1 oil port of the first direction flow control valve (3) and the P2 oil port of the second direction flow control valve (4), the other end being connected with the oil supply source.

2. The hydraulic cylinder friction test servo module of claim 1, wherein, the pressure control unit further comprising a first pressure sensor (7), the first pressure sensor (7) being arranged on the converging oil path, and being used for detecting and uploading oil pressure input by the oil supply source.

3. The hydraulic cylinder friction test servo module of claim 2, wherein, the pressure control unit further comprising a second pressure sensor (8) and a third pressure sensor (9), the second pressure sensor (8) being arranged between the A1 oil port of the first direction flow control valve (3) and the Pa oil port of the test element (1), the third pressure sensor (9) being arranged between the A2 oil port of the second direction flow control valve (4) and the Pb oil port of the test element (1), the second pressure sensor (8) and the third pressure sensor (9) being used for detecting and uploading oil pressure in the first oil path and the second oil path.

4. The hydraulic cylinder friction test servo module of claim 3, wherein, the pressure control unit further comprising a first pressure gauge (10), the first pressure gauge (10) being arranged on the converging oil path, and being used for measuring oil pressure input by the oil supply source.

5. The hydraulic cylinder friction test servo module of claim 2, wherein, ​ 6. The hydraulic cylinder friction test servo module of claim 5, wherein, The pressure control unit further comprises a second pressure gauge (11) and a third pressure gauge (12), the second pressure gauge (11) is arranged between the A1 oil port of the first direction flow control valve and the Pa oil port of the test element (1), the third pressure gauge (12) is arranged between the A2 oil port of the second direction flow control valve and the Pb oil port of the test element (1), the second pressure gauge (11) and the third pressure gauge (12) are used to measure the oil pressure in the pipelines of the first oil circuit and the second oil circuit.

7. The hydraulic cylinder friction test servo module of claim 6, wherein, The pressure control unit further comprises a first pressure gauge cut-off valve (13), the first pressure gauge cut-off valve (13) is arranged on the first pressure gauge (10) and is used to control the opening and closing of the measuring pipeline of the first pressure gauge (10).

8. The hydraulic cylinder friction test servo module of claim 7, wherein, The pressure control unit further comprises a second pressure gauge cut-off valve (14) and a third pressure gauge cut-off valve (15), the second pressure gauge cut-off valve (14) is arranged on the second pressure gauge (11), the third pressure gauge cut-off valve (15) is arranged on the third pressure gauge (12), the second pressure gauge cut-off valve (14) and the third pressure gauge cut-off valve (15) are used to control the opening and closing of the measuring pipelines of the second pressure gauge (11) and the third pressure gauge (12).

9. The hydraulic cylinder friction test servo module of claim 2, wherein, Further comprising an oil filter (16), the oil filter (16) is arranged on the converging oil circuit and is used to filter the pressure oil delivered by the oil supply source.

10. A hydraulic cylinder friction test system comprising the hydraulic cylinder friction test servo module of any one of claims 1-9, wherein, Further comprising an oil tank and an oil supply device, the oil supply device is used to extract the oil in the oil tank and deliver the oil to the execution oil circuit, the oil tank is further connected with the oil return circuit.

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