A multi-comprehensive vibration test system air pressure balance control system and method

Abstract

The present invention discloses a pressure balance control system and method for a multi-comprehensive vibration test system, comprising an air intake valve, a vacuum pump, a pipeline, a lower switch valve, an upper switch valve, a vibration table, a test box, a sensor system and a control unit, wherein the sensor system comprises a temperature sensor, an upper air pressure sensor, and a lower air pressure sensor, wherein the upper air pressure sensor is evenly distributed in a closed cavity of the test box, and the control unit collects state information of each sensor and controls the air intake valve, the vacuum pump, the lower switch valve, and the upper switch valve respectively in combination with the temperature change law during the test, and dynamically compensates for the pressure change caused by the temperature change, thereby realizing the balanced control of the air pressure in the closed cavity of the vibration table and the closed cavity of the test box. The system of the present invention is simple, low in cost, easy to install, highly adaptable, and has good use effect, and has wide practicability.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration tables, and in particular to an air pressure balance control system and method for a multi-integrated vibration test system. Background Art

[0002] At present, electric vibration tables are widely used in reliability research and testing of complete machines and parts of products in the aviation, aerospace, weapons, electronics, ships, machinery, energy, chemical industry, instrumentation and other departments. However, the experimental environment of some products is limited by environmental factors such as temperature, humidity, and air pressure, and vibration experiments cannot be carried out under special working conditions. The main method to solve this problem is to use the electric vibration table in conjunction with a comprehensive test box (used to simulate temperature, humidity, air pressure, and vibration environment). A crucial point in the use of a multi-comprehensive vibration test system is to achieve automatic balance of the air pressure inside the vibration table and the comprehensive test box. However, there are currently several deficiencies in the air pressure balance of the multi-comprehensive vibration test system:

[0003] 1. The existing multi-comprehensive vibration test system generally connects the inside of the vibration table with the inside of the comprehensive test box during air pressure equalization, and then uses a vacuum pump to simultaneously evacuate the inside of the connected vibration table and the inside of the comprehensive test box to simulate low pressure conditions. The vacuum pump usually runs at a fixed speed. If the speed of the vacuum pump is slow, it will take a long time to reach the desired air pressure. If the speed of the vacuum pump is too fast, it will easily cause the air pressure inside the comprehensive test box to be over-adjusted, resulting in poor air pressure equalization effect.

[0004] 2. The existing multi-comprehensive vibration test system generally ignores the change of air pressure in the comprehensive test box caused by the temperature rise during the temperature rise test in the comprehensive test box under low pressure environment, and does not take corresponding measures to dynamically compensate for the pressure change, resulting in poor pressure balance effect during the temperature rise test;

[0005] 3. In the existing low-pressure environment vibration test, when collecting the air pressure of the comprehensive test box, a single air pressure sensor is usually used to measure the air pressure of the comprehensive test box. The air pressure measurement in the comprehensive test box is not comprehensive and cannot accurately reflect the global air pressure value in the comprehensive test box. Air pressure equalization control based on this pressure value often causes a certain air pressure equalization error. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a multi-comprehensive vibration test system air pressure balance control system and method which has a simple structure, low cost and good use effect.

[0007] The present invention provides an air pressure balance control system for a multi-integrated vibration test system, comprising an intake valve, a vacuum pump, a pipeline, a lower switch valve, an upper switch valve, a vibration table, a test box, a sensor system and a control unit; the vibration table comprises a transition table, a moving coil and a cover body, the transition table is connected to the moving coil by screws, the moving coil and the cover body are connected by a seal, and a closed cavity of the vibration table is formed between the moving coil and the cover body by the seal; the test box is arranged above the transition table, the test box is connected to the transition table by a seal, and a closed cavity is arranged in the test box; the inlet end of the lower switch valve is connected to the closed cavity of the vibration table; the inlet end of the upper switch valve is connected to the closed cavity of the test box; the intake valve is an electromagnetic proportional reversing valve, and the valve opening is positively correlated with the current; the vacuum pump is arranged There are two gears of high speed and low speed; the pipeline is provided with an upper port, a lower port, a left port and a right port, the upper port is connected to the outlet end of the upper switch valve, the lower port is connected to the vacuum pump, the left port is connected to the outlet end of the intake valve, and the right port is connected to the outlet end of the lower switch valve; the sensor system includes a temperature sensor, an upper air pressure sensor, and a lower air pressure sensor, the upper air pressure sensor is evenly distributed in the closed cavity of the test box; the lower air pressure sensor is arranged in the closed cavity of the vibration table support part; the temperature sensor is arranged in the closed cavity of the test box; the control unit is used to collect the upper air pressure sensor signal, the lower air pressure sensor signal and the temperature sensor signal and to run the air pressure balance control method of the multi-integrated vibration test system provided by the present invention.

[0008] The present invention also provides a method for controlling air pressure balance of a multi-comprehensive vibration test system, comprising the following steps:

[0009] Step S1: Initially set the air pressure of the vibration test system before the vibration test begins. The value of the i-th upper air pressure sensor is recorded as P. i , where: i = 1, 2, 3...m, m is the number of upper air pressure sensors, the air pressure sensor closest to the upper switch valve is the first upper air pressure sensor; calculate the average value P of the m upper air pressure sensors 上 , P 上 The calculation formula is P 上 =(P1+P2+P3+...+P m ) / m; the rated speed of the vacuum pump is n 额 , high speed is n 高 , low speed is n 低 , where: n 高 and n 低 The expressions are n 高 =η 高 n 额 and n 低 =η 低 n 额 , η 高 and η低 They are high speed coefficient and low speed coefficient respectively;

[0010] Step S2, set the vacuum pump to run at a high speed to evacuate the airtight cavity of the test box and the airtight cavity of the vibration table, record the expected air pressure required for the vibration test as P, close the air inlet valve, open the upper switch valve and the lower switch valve, record δ P上 is the allowable error value of the air pressure in the closed cavity of the test chamber, α is the air pressure coefficient and α>1, collect the value P1 of the first upper air pressure sensor in real time and judge in real time whether |P1-αP|≤δ P上 Is it true if |P1-αP|≤δ P上 If |P1-αP|≤δ P上 If established, proceed to the next step;

[0011] Step S3: The vacuum pump uses a low speed to adjust the air pressure in the closed cavity of the test box and the closed cavity of the vibration table. When the closed cavity of the test box and the closed cavity of the vibration table reach the desired air pressure, the next step is performed. The vacuum pump uses a low speed to adjust the air pressure in the closed cavity of the test box and the closed cavity of the vibration table. The specific steps are:

[0012] Step S31, set the vacuum pump to run at a low speed, record δ P下 P is the allowable error value of the air pressure in the closed cavity of the vibration table. The values ​​of m upper air pressure sensors are collected in real time and calculated according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1 to obtain 上 , real-time acquisition of the pressure sensor value P 下 ;

[0013] Step S32: The value P calculated in real time based on the upper air pressure sensor 上 The value P collected in real time by the air pressure sensor 下 Compare and judge, if |PP 上 |>δ P上 And|PP 下 |>δ P下 , keep the upper switch valve and the lower switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |≤δ P上 And|PP 下 |>δ P下 , close the upper switch valve, keep the lower switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |>δ P上 And|PP 下 |≤δ P下 , then close the lower switch valve, keep the upper switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP上 |≤δ P上 And|PP 下 |≤δ P下 , directly proceed to the next step;

[0014] Step S33, judgment condition |PP 上 |≤δ P上 and |PP 下 |≤δ P下 Are they satisfied at the same time? If satisfied, |PP 上 |≤δ P上 And|PP 下 |≤δ P下 , indicating that the closed cavity of the test chamber and the closed cavity of the vibration table have reached the desired air pressure, close the upper switch valve, the lower switch valve and the vacuum pump; if it does not meet the |PP 上 |≤δ P上 And|PP 下 |≤δ P下 , then return to step S32;

[0015] Step S4: When performing a temperature rise test under low pressure, perform a temperature rise test pressure compensation at the same time. First, calculate the temperature difference ΔT of the temperature curve according to the temperature curve given by the temperature rise test. 升 , the initial temperature of the temperature curve is T 初 , the end temperature of the temperature curve is T 末 , ΔT 升 The calculation formula is ΔT 升 =T 末 -T 初 ;

[0016] Step S5: Determine ΔT 升 Whether ΔT is satisfied 升 <λ 下 , where: 下 is the lower limit of the temperature difference threshold, if ΔT 升 ≥λ 下 , then execute step S6; if ΔT 升 <λ 下 , to perform air pressure compensation of the closed cavity of the test box under small temperature difference, execute steps S51 to S52, the specific steps are as follows:

[0017] Step S51: collect the temperature sensor value T in real time and determine whether T≥T 初 +β 小 ΔT 升 Is it established, where: β 小 is a small temperature rise coefficient, if T ≥ T 初 +β 小 ΔT 升If T≥T 初 +β 小 ΔT 升 If established, open the upper switch valve, the vacuum pump runs at a low speed, and proceed to the next step;

[0018] Step S52: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true, if |PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S52 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation;

[0019] Step S6: Determine ΔT 升 Whether it satisfies λ 下 ≤ΔT 升 <λ 上 , where: 上 is the upper limit of the temperature difference threshold, if ΔT 升 ≥λ 上 , then execute step S7; if λ 下 ≤ΔT 升 <λ 上 , to perform air pressure compensation of the closed cavity of the test box under medium temperature difference, then execute steps S61 to S63, the specific steps are as follows:

[0020] Step S61: collect the value T of the temperature sensor in real time, record β 中 For medium temperature rise coefficient, judge T≥T 初 +β 中 ΔT 升 Is it true if T ≥ T 初 +β 中 ΔT 升 If T≥T 初 +β 中 ΔT 升 If established, open the upper switch valve, the vacuum pump runs at high speed, and execute the next step;

[0021] Step S62: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , denoted by P is the error value of vacuum pump speed conversion pressure, δP The value of is greater than δ P上 , real-time judgment |PP 上 |≤δ P Is it true, if |PP 上 |≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S62; if |PP 上 |≤δ P If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step;

[0022] Step S63: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true, if |PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S63 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation;

[0023] Step S7, performing air pressure compensation of the closed cavity of the test box under large temperature difference, comprising the following steps:

[0024] Step S71: collect the value T of the temperature sensor in real time, record β 高 For a high temperature rise coefficient, judge T≥T 初 +β 高 ΔT 升 Is it true if T ≥ T 初 +β 高 ΔT 升 If T≥T 初 +β 高 ΔT 升 If established, proceed to the next step;

[0025] Step S72: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P Is it true, if |PP 上 |≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S72; if |PP 上 |≤δP If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step;

[0026] Step S73: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true, if |PP 上 |≤δ P上 If the condition is not established, the upper switch valve is kept open, the vacuum pump continues to run at a low speed, and step S73 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation.

[0027] Preferably, the upper air pressure sensors are evenly distributed at the same height in the closed cavity of the test box.

[0028] Preferably, there are two or four upper air pressure sensors.

[0029] Preferably, the high gear speed coefficient η 高 The value range is 0.7~0.8, the low gear speed coefficient η 低 The value range is 0.5 to 0.6.

[0030] Preferably, the air pressure coefficient α ranges from 1.5 to 1.9.

[0031] Preferably, the permissible error value of the air pressure in the closed cavity of the test chamber is P上 The value range is 0.1Pa~0.3Pa, and the allowable error value of the air pressure in the closed cavity of the vibration table is δ P下 The value range is 0.1Pa~0.3Pa, the vacuum pump speed conversion pressure error value δ P The value range is 1Pa~1.5Pa.

[0032] Preferably, the lower limit of the temperature difference threshold λ 下 The value range is 100℃~200℃, and the upper limit of temperature difference threshold is λ 上 The value range is 500℃~600℃.

[0033] Preferably, a low temperature rise coefficient β 小 The value range is 0.6~0.65, the medium temperature rise coefficient β 中 The value range is 0.4~0.45, high temperature rise coefficient β 高 The value range is 0.3 to 0.35.

[0034] Beneficial effects:

[0035] 1. In the process of evacuating the airtight cavity of the vibration table test box and the airtight cavity of the vibration table, the vacuum pump used in the air pressure balance control method of the multi-comprehensive vibration test system proposed by the present invention adopts high speed and low speed operation according to different air pressure values, thereby shortening the time required for the air pressure of the airtight cavity of the vibration table test box and the airtight cavity of the vibration table to reach the desired air pressure, and improving the air pressure stability accuracy of the airtight cavity of the vibration table test box and the airtight cavity of the vibration table;

[0036] 2. The air pressure equalization control method of the multi-comprehensive vibration test system proposed in the present invention adopts different air pressure equalization control methods according to the different temperature differences between the initial temperature and the end temperature of the temperature curve during the temperature rise test. When the temperature difference is large or medium, the vacuum pump is operated at high speed and low speed to equalize the air pressure. When the temperature difference is small, the vacuum pump is operated at low speed to equalize the air pressure, thereby effectively ensuring the balance of the air pressure during the temperature rise experiment;

[0037] 3. The present invention evenly arranges a plurality of air pressure sensors at the same height in the closed cavity of the vibration table test box, and calculates the average value thereof as the air pressure value in the closed cavity of the vibration table test box, thereby improving the accuracy of air pressure detection;

[0038] 4. In the process of air pressure balance control of the multi-integrated vibration test system of the present invention, the vacuum pump only needs to be set to two gears, high and low, and there is no need to continuously adjust the speed of the vacuum pump. The system is simple, easy to construct, low cost, easy to install, simple and reliable, highly adaptable, and has good use effect, and has wide practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural principle diagram of the present invention.

[0040] Figure 2 Diagram of the arrangement of sensors in the test chamber of the present invention.

[0041] Figure 3 Air pressure initial setting control flow chart.

[0042] Figure 4 Temperature rise test air pressure compensation control flow chart.

[0043] 1. Inlet valve, 2. Vacuum pump, 3. Pipeline, 4. Lower switch valve, 5. Upper switch valve, 6. Transition table, 7. Closed cavity of test chamber, 8. Lower air pressure sensor, 9. Temperature sensor, 10. Upper air pressure sensor; 11. Test chamber, 12. Vibration table cover, 13. Closed cavity of vibration table, 14. Moving coil, 15. Control unit DETAILED DESCRIPTION

[0044] The present invention will be further described below with reference to the embodiments in the accompanying drawings:

[0045] The present invention provides an air pressure balance control system for a multi-integrated vibration test system, comprising an intake valve, a vacuum pump, a pipeline, a lower switch valve, an upper switch valve, a vibration table, a test box, a sensor system and a control unit; the vibration table comprises a transition table, a moving coil and a cover body, the transition table is connected to the moving coil by screws, the moving coil and the cover body are connected by a seal, and a closed cavity of the vibration table is formed between the moving coil and the cover body by the seal; the test box is arranged above the transition table, the test box is connected to the transition table by a seal, and a closed cavity is arranged in the test box; the inlet end of the lower switch valve is connected to the closed cavity of the vibration table; the inlet end of the upper switch valve is connected to the closed cavity of the test box; the intake valve is an electromagnetic proportional reversing valve, and the valve port opening is positively correlated with the current; the vacuum pump is provided with two types of high speed and low speed gear position; the pipeline is provided with an upper port, a lower port, a left port and a right port, the upper port is connected to the outlet end of the upper switch valve, the lower port is connected to the vacuum pump, the left port is connected to the outlet end of the intake valve, and the right port is connected to the outlet end of the lower switch valve; the sensor system includes a temperature sensor, an upper air pressure sensor, and a lower air pressure sensor, the upper air pressure sensors are evenly distributed in the closed cavity of the test box and are at the same height, and a total of 4 upper air pressure sensors are arranged; the lower air pressure sensor is arranged in the closed cavity of the vibration table support part; the temperature sensor is arranged in the closed cavity of the test box; the control unit is used to collect upper air pressure sensor signals, lower air pressure sensor signals and temperature sensor signals and to run the air pressure balancing control method of the multi-integrated vibration test system provided by the present invention.

[0046] The present invention also provides a method for controlling air pressure balance of a multi-comprehensive vibration test system, comprising the following steps:

[0047] Step S1: Initially set the air pressure of the vibration test system before the vibration test begins. The value of the i-th upper air pressure sensor is recorded as P. i , where: i = 1, 2, 3...m, m is the number of upper air pressure sensors, the air pressure sensor closest to the upper switch valve is the first upper air pressure sensor; calculate the average value P of the m upper air pressure sensors 上 , P 上 The calculation formula is P 上 =(P1+P2+P3+...+P m ) / m; the rated speed of the vacuum pump is n 额 , high speed is n 高 , low speed is n 低 , where: n 高 and n 低 The expressions are n 高 =η 高 n 额 and n 低 =η 低 n 额, η 高 and η 低 are high speed coefficient and low speed coefficient, respectively, 高 The value range is 0.7~0.8, η 低 The value range is 0.5~0.6;

[0048] Step S2, set the vacuum pump to run at a high speed to evacuate the airtight cavity of the test box and the airtight cavity of the vibration table, record the expected air pressure required for the vibration test as P, close the air inlet valve, open the upper switch valve and the lower switch valve, record δ P上 is the allowable error value of the air pressure in the closed cavity of the test chamber, δ P上 The value range is 0.1Pa~0.3Pa, α is the air pressure coefficient and α>1, α value range is 1.5~1.9, collect the value P1 of the first upper air pressure sensor in real time and judge in real time |P1-αP|≤δ P上 Is it true if |P1-αP|≤δ P上 If |P1-αP|≤δ P上 If established, proceed to the next step;

[0049] Step S3: The vacuum pump uses a low speed to adjust the air pressure in the closed cavity of the test box and the closed cavity of the vibration table. When the closed cavity of the test box and the closed cavity of the vibration table reach the desired air pressure, the next step is performed. The vacuum pump uses a low speed to adjust the air pressure in the closed cavity of the test box and the closed cavity of the vibration table. The specific steps are:

[0050] Step S31, set the vacuum pump to run at a low speed, record δ P下 is the allowable error value of the air pressure in the closed cavity of the vibration table, δ P下 The value range is 0.1Pa~0.3Pa, and the values ​​of m upper air pressure sensors are collected in real time and P is calculated according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , real-time acquisition of the pressure sensor value P 下 ;

[0051] Step S32: The value P calculated in real time based on the upper air pressure sensor 上 The value P collected in real time by the air pressure sensor 下 Compare and judge, if |PP 上 |>δ P上 And|PP 下 |>δ P下 , keep the upper switch valve and the lower switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |≤δ P上 And|PP 下 |>δ P下, close the upper switch valve, keep the lower switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |>δ P上 And|PP 下 |≤δ P下 , then close the lower switch valve, keep the upper switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |≤δ P上 And|PP 下 |≤δ P下 , directly proceed to the next step;

[0052] Step S33, judgment condition |PP 上 |≤δ P上 and |PP 下 |≤δ P下 Are they satisfied at the same time? If satisfied, |PP 上 |≤δ P上 And|PP 下 |≤δ P下 , indicating that the closed cavity of the test chamber and the closed cavity of the vibration table have reached the desired air pressure, close the upper switch valve, the lower switch valve and the vacuum pump; if it does not meet the |PP 上 |≤δ P上 And|PP 下 |≤δ P下 , then return to step S32;

[0053] Step S4: When performing a temperature rise test under low pressure, perform a temperature rise test pressure compensation at the same time. First, calculate the temperature difference ΔT of the temperature curve according to the temperature curve given by the temperature rise test. 升 , the initial temperature of the temperature curve is T 初 , the end temperature of the temperature curve is T 末 , ΔT 升 The calculation formula is ΔT 升 =T 末 -T 初 ;

[0054] Step S5: Determine ΔT 升 Whether ΔT is satisfied 升 <λ 下 , where: 下 is the lower limit of the temperature difference threshold, λ 下 The value range is 100℃~200℃. If ΔT 升 ≥λ 下 , then execute step S6; if ΔT 升 <λ 下 , to perform air pressure compensation of the closed cavity of the test box under small temperature difference, execute steps S51 to S52, the specific steps are as follows:

[0055] Step S51: collect the temperature sensor value T in real time and determine whether T≥T 初 +β 小 ΔT 升 Is it established, where: β 小 is the small temperature rise coefficient, β 小 The value range is 0.6~0.65. If T≥T 初 +β 小 ΔT 升 If T≥T 初 +β 小 ΔT 升 If established, open the upper switch valve, the vacuum pump runs at a low speed, and proceed to the next step;

[0056] Step S52: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true, if |PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S52 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation;

[0057] Step S6: Determine ΔT 升 Whether it satisfies λ 下 ≤ΔT 升 <λ 上 , where: 上 is the upper limit of the temperature difference threshold, λ 上 The value range is 500℃~600℃. If ΔT 升 ≥λ 上 , then execute step S7; if λ 下 ≤ΔT 升 <λ 上 , to perform air pressure compensation of the closed cavity of the test box under medium temperature difference, then execute steps S61 to S63, the specific steps are as follows:

[0058] Step S61: collect the value T of the temperature sensor in real time, record β 中 is the medium temperature rise coefficient, β 中 The value range is 0.4~0.45, judging T≥T 初 +β 中 ΔT 升 Is it true if T ≥ T 初 +β 中ΔT 升 If T≥T 初 +β 中 ΔT 升 If established, open the upper switch valve, run the vacuum pump at high speed, and proceed to the next step;

[0059] Step S62: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , denoted by P is the error value of vacuum pump speed conversion pressure, δ P The value of is greater than δ P上 , δ P The value range is 1Pa~1.5Pa, real-time judgment|PP 上 |≤δ P Is it true, if |PP 上 v≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S62; if |PP 上 |≤δ P If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step;

[0060] Step S63: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true, if |PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S63 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation;

[0061] Step S7, performing air pressure compensation of the closed cavity of the test box under large temperature difference, comprising the following steps:

[0062] Step S71: collect the value T of the temperature sensor in real time, record β 高 is a high temperature rise coefficient, β 高 The value range is 0.3~0.35, judging T≥T 初 +β 高 ΔT 升 Is it true if T ≥ T 初 +β 高 ΔT 升If T≥T 初 +β 高 ΔT 升 If established, proceed to the next step;

[0063] Step S72: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 v≤δ P Is it true, if |PP 上 |≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S72; if |PP 上 v≤δ P If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step;

[0064] Step S73: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true, if |PP 上 |≤δ P上 If the condition is not established, the upper switch valve is kept open, the vacuum pump continues to run at a low speed, and step S73 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation.

[0065] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Various changes that can be made within the knowledge scope of technicians in the relevant technical field without departing from the spirit of the present invention are all within the protection scope of the claims of the present invention.

Claims

1. A multi-comprehensive vibration test system air pressure balance control system, characterized in that: include: Inlet valve, vacuum pump, pipeline, lower switch valve, upper switch valve, vibration table, test chamber, sensor system and control unit; The vibration table comprises a transition table, a moving coil and a cover body, the transition table is connected to the moving coil by screws, the moving coil and the cover body are connected by a seal, and a closed cavity of the vibration table is formed between the moving coil and the cover body by the seal; the test box is arranged above the transition table, the test box is connected to the transition table by a seal, and a closed cavity is arranged in the test box; The inlet end of the lower switch valve is connected to the closed cavity of the vibration table; the inlet end of the upper switch valve is connected to the closed cavity of the test box; the air intake valve is an electromagnetic proportional reversing valve, and the valve opening is positively correlated with the current; the vacuum pump is provided with two gears of high speed and low speed; the pipeline is provided with an upper port, a lower port, a left port and a right port, the upper port is connected to the outlet end of the upper switch valve, the lower port is connected to the vacuum pump, the left port is connected to the outlet end of the air intake valve, and the right port is connected to the outlet end of the lower switch valve; The sensor system includes a temperature sensor, an upper air pressure sensor, and a lower air pressure sensor. The upper air pressure sensor is evenly distributed in the closed cavity of the test box; the lower air pressure sensor is arranged in the closed cavity of the vibration table support part; the temperature sensor is arranged in the closed cavity of the test box; The control unit is used to collect the upper air pressure sensor signal, the lower air pressure sensor signal and the temperature sensor signal and to run the air pressure equalization control method of the multi-integrated vibration test system; the air pressure equalization control method of the multi-integrated vibration test system comprises the following steps: Step S1: Initially set the air pressure of the vibration test system before the vibration test begins. The value of the i-th upper air pressure sensor is recorded as P. i , where: i = 1, 2, 3...m, m is the number of upper air pressure sensors, the air pressure sensor closest to the upper switch valve is the first upper air pressure sensor; calculate the average value P of the m upper air pressure sensors 上 , P 上 The calculation formula is P 上 =(P1+P2+P3+...+P m ) / m; the rated speed of the vacuum pump is n 额 , high speed is n 高 , low speed is n 低 , where: n 高 and n 低 The expressions are n 高 =η 高 n 额 and n 低 =η 低 n 额 , η 高 and η 低 They are high speed coefficient and low speed coefficient respectively; Step S2, set the vacuum pump to run at a high speed to evacuate the airtight cavity of the test box and the airtight cavity of the vibration table, record the expected air pressure required for the vibration test as P, close the air inlet valve, open the upper switch valve and the lower switch valve, record δ P上 is the allowable error value of the air pressure in the closed cavity of the test chamber, α is the air pressure coefficient and α>1, collect the value P1 of the first upper air pressure sensor in real time and judge in real time whether |P1-αP|≤δ P上 Is it true if P1-αP|≤δ P上 If |P1-αP|≤δ P上 If established, proceed to the next step; Step S3, the vacuum pump uses a low speed to adjust the air pressure of the closed cavity of the test box and the closed cavity of the vibration table. When the closed cavity of the test box and the closed cavity of the vibration table reach the desired air pressure, the next step is performed; Step S4: When performing a temperature rise test under low pressure, perform a temperature rise test pressure compensation at the same time. First, calculate the temperature difference ΔT of the temperature curve according to the temperature curve given by the temperature rise test. 升 , the initial temperature of the temperature curve is T 初 , the end temperature of the temperature curve is T 末 , ΔT 升 The calculation formula is ΔT 升 =T 末 -T 初 ; Step S5: Determine ΔT 升 Whether ΔT is satisfied 升 <λ 下 , where: 下 is the lower limit of the temperature difference threshold, if ΔT 升 ≥λ 下 , then execute step S6; if ΔT 升 <λ 下 , to perform air pressure compensation of the closed cavity of the test box under small temperature difference, execute steps S51 to S52, the specific steps are as follows: Step S51: collect the temperature sensor value T in real time and determine whether T≥T 初 +β 小 ΔT 升 Is it established, where: β 小 is a small temperature rise coefficient, if T ≥ T 初 +β 小 ΔT 升 If T≥T 初 +β 小 ΔT 升 If established, open the upper switch valve, the vacuum pump runs at a low speed, and proceed to the next step; Step S52: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true? If PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S52 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation; Step S6: Determine ΔT 升 Whether λ is satisfied 下 ≤ΔT 升 <λ 上 , where: 上 is the upper limit of the temperature difference threshold, if ΔT 升 ≥λ 上 , then execute step S7; if λ 下 ≤ΔT 升 <λ 上 , to perform air pressure compensation of the closed cavity of the test box under medium temperature difference, then execute steps S61 to S63, the specific steps are as follows: Step S61: collect the value T of the temperature sensor in real time, record β 中 For medium temperature rise coefficient, judge T≥T 初 +β 中 ΔT 升 Is it true if T ≥ T 初 +β 中 ΔT 升 If T≥T 初 +β 中 ΔT 升 If established, open the upper switch valve, run the vacuum pump at high speed, and proceed to the next step; Step S62: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , denoted by P is the error value of vacuum pump speed conversion pressure, δ P The value of is greater than δ P上 , real-time judgment |PP 上 |≤δ P Is it true, if |PP 上 |≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S62; if |PP 上 |≤δ P If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step; Step S63: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true? If PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S63 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation; Step S7, performing air pressure compensation of the closed cavity of the test box under large temperature difference, comprising the following steps: Step S71: collect the value T of the temperature sensor in real time, record β 高 For a high temperature rise coefficient, judge T≥T 初 +β 高 ΔT 升 Is it true if T ≥ T 初 +β 高 ΔT 升 If T≥T 初 +β 高 ΔT 升 If established, proceed to the next step; Step S72: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P Is it true? If PP 上 |≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S72; if |PP 上 |≤δ P If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step; Step S73: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true? If PP 上 |≤δ P上 If not, keep the upper switch valve open, the vacuum pump continues to run at a low speed, and repeat step S73; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation.

2. The air pressure balance control system of a multi-integrated vibration test system according to claim 1 is characterized in that: The upper air pressure sensors are evenly distributed at the same height in the closed cavity of the test box.

3. The air pressure balance control system of a multi-integrated vibration test system according to claim 1 is characterized in that: The number of the upper air pressure sensors is two or four.

4. A control method using the air pressure balance control system of a multi-integrated vibration test system as claimed in claim 1, characterized in that: The control method comprises the following steps: Step S1: Initially set the air pressure of the vibration test system before the vibration test begins. The value of the i-th upper air pressure sensor is recorded as P. i , where: i = 1, 2, 3...m, m is the number of upper air pressure sensors, the air pressure sensor closest to the upper switch valve is the first upper air pressure sensor; calculate the average value P of the m upper air pressure sensors 上 , P 上 The calculation formula is P 上 =(P1+P2+P3+...+P m ) / m; the rated speed of the vacuum pump is n 额 , high speed is n 高 , low speed is n 低 , where: n 高 and n 低 The expressions are n 高 =η 高 n 额 and n 低 =η 低 n 额 , η 高 and η 低 They are high speed coefficient and low speed coefficient respectively; Step S2, set the vacuum pump to run at a high speed to evacuate the airtight cavity of the test box and the airtight cavity of the vibration table, record the expected air pressure required for the vibration test as P, close the air inlet valve, open the upper switch valve and the lower switch valve, record δ P上 is the allowable error value of the air pressure in the closed cavity of the test chamber, α is the air pressure coefficient and α>1, collect the value P1 of the first upper air pressure sensor in real time and judge in real time whether |P1-αP|≤δ P上 Is it true if P1-αP|≤δ P上 If |P1-αP|≤δ P上 If established, proceed to the next step; Step S3, the vacuum pump uses a low speed to adjust the air pressure of the closed cavity of the test box and the closed cavity of the vibration table. When the closed cavity of the test box and the closed cavity of the vibration table reach the desired air pressure, the next step is performed; Step S4: When performing a temperature rise test under low pressure, perform a temperature rise test pressure compensation at the same time. First, calculate the temperature difference ΔT of the temperature curve according to the temperature curve given by the temperature rise test. 升 , the initial temperature of the temperature curve is T 初 , the end temperature of the temperature curve is T 末 , ΔT 升 The calculation formula is ΔT 升 =T 末 -T 初 ; Step S5: Determine ΔT 升 Whether ΔT is satisfied 升 <λ 下 , where: 下 is the lower limit of the temperature difference threshold, if ΔT 升 ≥λ 下 , then execute step S6; if ΔT 升 <λ 下 , to perform air pressure compensation of the closed cavity of the test box under small temperature difference, execute steps S51 to S52, the specific steps are as follows: Step S51: collect the temperature sensor value T in real time and determine whether T≥T 初 +β 小 ΔT 升 Is it established, where: β 小 is a small temperature rise coefficient, if T ≥ T 初 +β 小 ΔT 升 If T≥T 初 +β 小 ΔT 升 If established, open the upper switch valve, the vacuum pump runs at a low speed, and proceed to the next step; Step S52: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true? If PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S52 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation; Step S6: Determine ΔT 升 Whether λ is satisfied 下 ≤ΔT 升 <λ 上 , where: 上 is the upper limit of the temperature difference threshold, if ΔT 升 ≥λ 上 , then execute step S7; if λ 下 ≤ΔT 升 <λ 上 , to perform air pressure compensation of the closed cavity of the test box under medium temperature difference, then execute steps S61 to S63, the specific steps are as follows: Step S61: collect the value T of the temperature sensor in real time, record β 中 For medium temperature rise coefficient, judge T≥T 初 +β 中 ΔT 升 Is it true if T ≥ T 初 +β 中 ΔT 升 If T≥T 初 +β 中 ΔT 升 If established, open the upper switch valve, run the vacuum pump at high speed, and proceed to the next step; Step S62: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , denoted by P is the error value of vacuum pump speed conversion pressure, δ P The value of is greater than δ P上 , real-time judgment |PP 上 |≤δ P Is it true, if |PP 上 |≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S62; if |PP 上 |≤δ P If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step; Step S63: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true? If PP 上 |≤δ P上 If the upper switch valve is not established, the vacuum pump continues to run at a low speed and step S63 is repeated; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation; Step S7, performing air pressure compensation of the closed cavity of the test box under large temperature difference, comprising the following steps: Step S71: collect the value T of the temperature sensor in real time, record β 高 For a high temperature rise coefficient, judge T≥T 初 +β 高 ΔT 升 Is it true if T ≥ T 初 +β 高 ΔT 升 If T≥T 初 +β 高 ΔT 升 If established, proceed to the next step; Step S72: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P Is it true? If PP 上 |≤δ P If not established, keep the upper switch valve open, the vacuum pump runs at a high speed, and repeat step S72; if |PP 上 |≤δ P If established, keep the upper switch valve open, the vacuum pump runs at a low speed, and proceed to the next step; Step S73: collect m upper air pressure sensor values ​​in real time and calculate P according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1. 上 , and make real-time judgment |PP 上 |≤δ P上 Is it true? If PP 上 |≤δ P上 If not, keep the upper switch valve open, the vacuum pump continues to run at a low speed, and repeat step S73; if |PP 上 |≤δ P上 Establish, close the upper switch valve and vacuum pump, and end the temperature rise test pressure compensation.

5. The control method according to claim 4, characterized in that: In step S3, the specific steps of using the vacuum pump at a low speed to adjust the air pressure in the closed cavity of the test box and the closed cavity of the vibration table are as follows: Step S31, set the vacuum pump to run at a low speed, record δ P下 P is the allowable error value of the air pressure in the closed cavity of the vibration table. The values ​​of m upper air pressure sensors are collected in real time and calculated according to the average value calculation formula of the m upper air pressure sensor values ​​in step S1 to obtain 上 , real-time acquisition of the pressure sensor value P 下 ; Step S32: The value P calculated in real time based on the upper air pressure sensor 上 The value P collected in real time by the air pressure sensor 下 Compare and judge, if |PP 上 |>δ P上 And|PP 下 |>δ P下 , keep the upper switch valve and the lower switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |≤δ P上 And|PP 下 |>δ P下 , close the upper switch valve, keep the lower switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |>δ P上 And|PP 下 |≤δ P下 , close the lower switch valve, keep the upper switch valve open, the vacuum pump continues to run at a low speed, and then proceed to the next step; if |PP 上 |≤δ P上 And PP 下 |≤δ P下 , directly proceed to the next step; Step S33, judgment condition |PP 上 |≤δ P上 and |PP 下 |≤δ P下 Are they satisfied at the same time? If PP is satisfied 上 |≤δ P上 And|PP 下 |≤δ P下 , indicating that the closed cavity of the test chamber and the closed cavity of the vibration table have reached the desired air pressure, close the upper switch valve, the lower switch valve and the vacuum pump; if it does not meet the |PP 上 |≤δ P上 And|PP 下 |≤δ P下 , then return to step S32.

6. The control method according to claim 4, characterized in that: High gear speed coefficient η 高 The value range is 0.7~0.8, the low gear speed coefficient η 低 The value range is 0.5 to 0.6, and the value range of the air pressure coefficient α is 1.5 to 1.

9.

7. The control method according to claim 4, characterized in that: Permissible error value of air pressure in the closed cavity of the test chamber δ P上 The value range is 0.1Pa~0.3Pa, the vacuum pump speed conversion pressure error value δ P The value range is 1Pa~1.5Pa.

8. The control method according to claim 4, characterized in that: Temperature difference threshold lower limit λ 下 The value range is 100℃~200℃, and the upper limit of temperature difference threshold is λ 上 The value range is 500℃~600℃.

9. The control method according to claim 4, characterized in that: Low temperature rise coefficient β 小 The value range is 0.6~0.65, the medium temperature rise coefficient β 中 The value range is 0.4~0.45, high temperature rise coefficient β 高 The value range is 0.3 to 0.

35.

10. The control method according to claim 5, characterized in that: The allowable error value of the air pressure in the closed cavity of the vibration table δ P下 The value range is 0.1Pa~0.3Pa.

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