Multi-channel air spring displacement loading system and control method thereof

Abstract

The invention discloses a multichannel air spring displacement loading system and a control system thereof. The multichannel air spring displacement loading system comprises a tool (1), a pressure sensor (2), an air spring (3), a laser displacement sensor (4), a guide mechanism (5) and a limiting mechanism (6), the tool 1 is of a rigid structure, is located on the upper floating face of the air spring 3 and serves as a common lifting face of the upper surface of the air spring 3. The lower surface of the tool (1) is fixedly connected with the upper surface of the air spring (3), and the lower surface of the air spring (3) is fixedly connected with a foundation; the pressure sensors (2) are installed on the air springs (3) and used for measuring the real-time air pressure in each air spring and transmitting the real-time air pressure to the control system through signal cables. Each independent air spring is matched with a pressure sensor (2); the air springs (3) are actuating mechanisms for realizing displacement loading, and a plurality of air springs (3) are arranged; the laser displacement sensors (4) are installed on the sides of the air springs and used for measuring the displacement changes of the upper surfaces and the lower surfaces close to the air springs (3) and transmitting the displacement changes to a control system through signal cables, and each independent air spring (3) is matched with the corresponding laser displacement sensor (4). Under the no-load condition of the tool (1), the guide mechanism (5) is installed, it is guaranteed that the floating and falling processes of the tool (1) are stable, and resultant force generated by the air spring (3) is not suddenly changed.

Description

Technical Field

[0001] This invention belongs to the field of vibration testing technology, specifically involving the application of multiple air springs used together to support the same rigid structure, and is applicable in situations where high positional accuracy is required, such as when vibration testing is performed after displacement loading of the test piece. Background Technology

[0002] In liquid-fueled spacecraft such as launch vehicles, the fuel in the storage tanks needs to be pressurized and transported to the engine through fuel delivery pipelines. Simultaneously, during normal engine operation, engine vibrations can be transmitted to the fuel storage tanks via these pipelines, which typically contain a pressure of around 1 MPa. To fully simulate the operating conditions of the fuel delivery pipelines during ground testing, vibration tests under static loads with flexible displacement are necessary.

[0003] During ground testing, flexible displacement loading can be achieved using air springs. For conditions with large dimensions or significant reaction forces during displacement loading, multiple air springs are typically required to be arranged separately and loaded together. Since the test requires complex vibration conditions, the structure or fixture supported by multiple air springs has high stiffness. For multi-point (4 points or more) synchronous positioning control systems, which are typically statically indeterminate systems, prolonged position maintenance without the theoretical bearing capacity of a single point may lead to excessively large or small loads on individual air springs, introducing test risks. Summary of the Invention

[0004] (I) Technical problems to be solved This invention discloses a multi-channel air spring displacement loading system and its control method, which uses a combination of pressure and displacement control to achieve high-precision flexible displacement loading.

[0005] (II) Technical Solution A multi-channel air spring displacement loading system includes tooling, a pressure sensor, an air spring, a laser displacement sensor, a guide mechanism, and a limiting mechanism; The fixture is a rigid structure located on the upper surface of the air spring, serving as a common support surface for the upper surface of the air spring; the lower surface of the fixture is fixed to the upper surface of the air spring by bolts, and the lower surface of the air spring is fixed to the foundation by bolts. The pressure sensor is mounted on the air spring to measure the real-time air pressure inside each air spring and transmits the data to the control system via a signal cable; each independent air spring is equipped with a pressure sensor. The air spring 3 is the actuator for realizing displacement loading, and multiple air springs are provided; The laser displacement sensor is installed on the side of the air spring to measure the displacement changes of the upper and lower surfaces near the air spring and transmits the data to the control system via a signal cable. Each independent air spring is equipped with a laser displacement sensor. The lower end of the guide mechanism is fixed to the ground when stationary, and the upper end, which moves axially, is fixed to the tooling. This is used to retain only the vertical degree of freedom and constrain the degrees of freedom in other directions, so as to prevent the tooling 1 from generating angular motion in the pitch and roll directions during the movement. Limiting mechanisms are installed at both ends of the tooling, and the limiting mechanisms are fixed to the foundation by bolts; When the tooling is unloaded, install a guide mechanism to ensure that the tooling floats and falls smoothly and that the resultant force generated by the air spring does not change abruptly.

[0006] Furthermore, if the air chambers of multiple air springs are connected, then the interconnected air springs are considered as an independent air spring.

[0007] Furthermore, lugs are provided at both ends of the tooling, which work in conjunction with the flange structure to limit the range of motion of the tooling in the vertical direction and prevent the tooling from being positioned too high or too low. The system installation method and process are as follows: A1: Based on the approximate load distribution and loading stroke requirements of the tooling, select and arrange air springs. A2: Select and arrange air springs. A3: Based on the vibration frequency requirements of the tooling test process, design the vertical support frequency of the air spring and install the corresponding additional air chamber; A4: When the tooling is unloaded, install a guide mechanism to ensure that the tooling floats and falls smoothly and that the resultant force generated by the air spring does not change abruptly. A5 designed and installed a limit mechanism 6 according to the loading stroke requirements.

[0008] A control method for a multi-channel air spring displacement loading system, the process of which is as follows: B1: With the fixture unloaded, use all air springs to slowly control the position, float the fixture to the test position and hold it there, and record the load distribution values ​​of all air springs 3. B2: Apply 30% and 60% of the maximum test static load to the tooling step by step, and record the load distribution values ​​of all air springs respectively; B3: Based on the load variation trend of each air spring, extrapolate the load distribution value of all air springs when the fixture is subjected to 60%-100% static load, and calculate the load distribution ratio. For example, the ratio of n air springs is 1:f2:f3:f4……fn. B4: When the self-weight of the tooling is less than 10% of the maximum static load borne by the tooling, it can be considered that the load distribution of the air spring under 60% static load is no different from the load distribution of the extrapolated air spring under 60%-100% static load. B4: Select the three air springs located near the edge of the tooling and set them to displacement closed-loop control mode; set the remaining air springs to load closed-loop control mode. B5: During the loading process, two types of air springs and two control modes coexist.

[0009] (III) Beneficial technical effects This invention enables high-precision flexible displacement loading. It is particularly suitable for applications requiring high-precision multi-channel displacement loading on flexible boundaries, eliminating the need for prior knowledge of the theoretical load at a single point and preventing situations where the load distribution is not ideal.

[0010] To ensure the safety and effectiveness of the experiment, this invention incorporates a limiting device and a guiding device in its hardware design, facilitating integrated testing with other testing equipment such as vibration tables. Attached Figure Description

[0011] Figure 1 : A structural diagram of a multi-channel air spring displacement loading system; Wherein: 1-tooling; 2-pressure sensor; 3-air spring; 4-laser displacement sensor; 5-guide mechanism; 6-limiting mechanism; Figure 2 : A control flowchart of a multi-channel air spring displacement loading system; Detailed Implementation

[0012] Besides the embodiments described below, the present invention may also have other embodiments or be implemented in different ways. Therefore, it should be understood that the present invention is not limited to the details of the results described in the following specification or shown in the accompanying drawings. When only one embodiment is described herein, the claims are not limited to that embodiment.

[0013] like Figure 1 As shown, the present invention provides a multi-channel air spring displacement loading system, comprising a tooling 1, pressure sensors 2 (10 in the system), air springs 3 (10 in the system), laser displacement sensors 4 (10 in the system), a guide mechanism 5 (3 in the system), and a limiting mechanism 6 (3 in the system).

[0014] The fixture 1 is a rigid structure that serves as a common support surface for the upper surface of the air spring. The design of the fixture 1, including its shape, thickness, and whether it has holes, is entirely dependent on the test conditions.

[0015] The pressure sensor 2 is used to measure the real-time air pressure inside each air spring and transmits the data to the control system via a signal cable. Each individual air spring is equipped with a pressure sensor 2.

[0016] If the air chambers of multiple air springs 3 are connected, the interconnected air springs are considered as an independent air spring.

[0017] The air spring 3 is the actuator for realizing displacement loading. The system can select and match the air spring according to factors such as load conditions, load distribution, displacement loading requirements, and spatial conditions.

[0018] The laser displacement sensor 4 is used to measure the displacement changes of the upper and lower surfaces near the air spring 3 and transmits the data to the control system via a signal cable. Each independent air spring is equipped with a laser displacement sensor 4.

[0019] The guide mechanism 5 is used to retain only the vertical motion degree of freedom and constrain the other directional degrees of freedom to prevent the tooling 1 from generating angular motion in the pitch and roll directions during the motion.

[0020] The limiting mechanism 6, in conjunction with the lugs, flanges and other structures on the tooling 1, is used to limit the range of motion of the tooling 1 in the vertical direction and prevent the tooling 1 from being in a position that is too high or too low.

[0021] The installation process of a multi-channel air spring displacement loading system is as follows: The selection and arrangement of air spring 3 are based on the load or load distribution on tooling 1 and the loading stroke requirements. Based on the vibration frequency requirements of the test process of tooling 1, the vertical support frequency of air spring 3 is designed, and the corresponding additional air chamber is installed. When tooling 1 is unloaded, install guide mechanism 5 to ensure that the upward and downward process of tooling 1 is smooth and that the resultant force generated by air spring 3 is not abrupt. Based on the loading stroke requirements, limit mechanism 6 was designed and installed.

[0022] A control method for a multi-channel air spring displacement loading system, the process of which is as follows: With fixture 1 unloaded, use all air springs 3 to slowly control the position, float fixture 1 to the test position and hold it there, and record the load distribution values ​​of all air springs 3; Apply 30% and 60% of the maximum test static load to fixture 1 in stages, and record the load distribution values ​​of all air springs 3 respectively; Based on the load variation trend of each air spring 3, extrapolate the load distribution values ​​of all air springs 3 when the fixture 1 bears 60%-100% static load, and calculate the load distribution ratio. For example, the ratio of n air springs is 1:f2:f3:f4……fn. When the weight of tooling 1 is less than 10% of the maximum static load borne by tooling 1, it can be considered that the load distribution of air spring 3 under 60% static load is no different from the load distribution of outward air spring 3 under 60%-100% static load. Among all the air springs 3, select three air springs 3 located close to the edge of tooling 1 and set them to displacement closed-loop control mode, such as air springs 3 numbered [k2], [k6], and [k10]. Set the remaining air springs 3 to load closed-loop control mode.

[0023] During the loading process, two types of air springs 3 and two control modes coexist.

[0024] like Figure 2 As shown, the following is an example of a 10-channel air spring with 3 closed-loop control. The specific control method is as follows.

[0025] For ease of representation, the load feedback value for each channel is calculated as follows: ; During the loading process, the control strategy ensures that the total load of the displacement control channel is within a certain range. Interval.

[0026] The load fine-tuning value x in the control strategy ranges from 0.01 to 0.05.

[0027] The initial value of the load command is set by the operator, and this value should generally not exceed the weight of tooling 1.

[0028] Displacement commands are set by the operator according to the working conditions.

[0029] Therefore, this invention discloses a multi-channel air spring displacement loading system and its control method, which can achieve the following technical effects: high-precision flexible displacement loading is achieved by using a combination of pressure and displacement control. This invention discloses the system composition, system installation process, and system control method. Applying this invention can achieve high-precision loading of multi-channel air spring displacement. For experimental safety and effectiveness, this invention incorporates limiting and guiding devices in its hardware design, facilitating integrated testing with vibration tables and other experimental equipment.

[0030] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A multi-channel air spring displacement loading system, characterized in that: Includes tooling (1), pressure sensor (2), air spring (3), laser displacement sensor (4), guide mechanism (5), and limit mechanism (6); The fixture 1 is a rigid structure located on the upper surface of the air spring 3, serving as a common support surface for the upper surface of the air spring (3); the lower surface of the fixture (1) is fixedly connected to the upper surface of the air spring (3), and the lower surface of the air spring (3) is fixedly connected to the foundation. The pressure sensor (2) is installed on the air spring (3) to measure the real-time air pressure in each air spring and transmit it to the control system via a signal cable; each independent air spring is equipped with a pressure sensor (2). The air spring (3) is an actuator for realizing displacement loading, and multiple air springs (3) are provided; The laser displacement sensor (4) is installed on the side of the air spring to measure the displacement change of the upper and lower surfaces near the air spring 3 and transmits it to the control system through a signal cable. Each independent air spring (3) is equipped with a laser displacement sensor (4). The lower end of the guide mechanism (5) is fixed to the ground while the upper end is fixed to the tooling (1) for axial movement. This is to retain only the vertical degree of freedom and constrain the other degrees of freedom to prevent the tooling 1 from generating angular motion in the pitch and roll directions during the movement. Limiting mechanisms (6) are installed at both ends of the tooling; When the tooling (1) is unloaded, install the guide mechanism (5) to ensure that the tooling (1) floats and falls smoothly and that the resultant force generated by the air spring (3) does not change abruptly.

2. The system as described in claim 1, characterized in that: If the air chambers of multiple air springs (3) are connected, the interconnected air springs are considered as an independent air spring.

3. The system as described in claim 1, characterized in that: The tooling (1) is provided with lugs at both ends, which are used in conjunction with the flange structure to limit the range of motion of the tooling (1) in the vertical direction and prevent the tooling 1 from being in a position that is too high or too low.

4. The installation method of the system as described in claim 1, characterized in that: The process is as follows: A1: Based on the load or load distribution on the tooling (1), loading stroke requirements, etc., select and arrange the air springs (3); A3: Based on the vibration frequency requirements of the test process of tooling 1, design the vertical support frequency of the air spring (3) and install the corresponding additional air chamber; A4: When the tooling (1) is unloaded, install the guide mechanism (5) to ensure that the tooling (1) floats and falls smoothly and that the resultant force generated by the air spring (3) does not change abruptly. A5 designs and installs a limit mechanism (6) according to the loading stroke requirements.

5. A control method for a multi-channel air spring displacement loading system, characterized in that, The process is as follows: B1: When the fixture (1) is unloaded, use all the air springs (3) to slowly control the position, float the fixture 1 to the test position and hold it, and record the load distribution value of all the air springs (3). B2: Apply 30% and 60% of the maximum test static load to the fixture (1) step by step, and record the load distribution values ​​of all air springs (3) respectively; B3: Based on the load change trend of each air spring (3), extrapolate the load distribution value of all air springs 3 when the fixture (1) bears 60%-100% static load, and calculate the load distribution ratio. For example, the ratio of n air springs is 1:f2:f3:f4……fn; B4: When the self-weight of tooling (1) is less than 10% of the maximum static load borne by tooling 1, it can be considered that the load distribution of air spring (3) under 60% static load is no different from the load distribution of outward air spring (3) under 60%-100% static load. B4: Select three air springs (3) whose positions are close to the edge of the tooling (1) and set them to displacement closed-loop control mode; set the remaining air springs (3) to load closed-loop control mode. B5: During the loading process, two types of air springs (3) exist simultaneously, and two control modes coexist.

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