Wide-range high-precision flow control system and method

Abstract

The invention belongs to the technical field of aviation testing, and relates to a wide-range high-precision flow control system and method.The system comprises a large-flow pump assembly, a small-flow pump assembly, a middle pipeline, a large-flow adjusting pipeline, a small-flow adjusting pipeline, a control unit and an oil outlet pipeline; the other ends of the large-flow pump assembly and the small-flow pump assembly are connected with one end of the middle pipeline; the other ends of the large-flow adjusting pipeline and the small-flow adjusting pipeline are connected with the oil outlet pipeline; the control unit is connected with and controls the large-flow pump assembly, the small-flow pump assembly, the large-flow adjusting pipeline and the small-flow adjusting pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation testing and relates to a wide-range high-precision flow control system and method. Background Art

[0002] The flow control accuracy of the test system is one of the core conditions for the performance test of liquid-cooled accessories. The test flow range of liquid-cooled test products ranges from 2L / min to 500L / min, and different liquid-cooled test products have different requirements for the test flow and its accuracy. The test system needs to provide a flow control system with a wide adjustment range and high accuracy. The existing flow control system has a narrow flow adjustment range and a small upper and lower limit range. When the system flow range is designed to be wide, the system's adjustment accuracy will be greatly reduced. Conventional control systems are difficult to simultaneously meet the system design of a wide flow range and high-precision adjustment, and cannot meet the test requirements of liquid-cooled test products. Summary of the invention

[0003] Purpose of the invention: In order to solve the technical problems of narrow flow regulation range and low control accuracy in testing liquid-cooled test products, the present invention provides a wide-range and high-precision flow control system and method.

[0004] Technical Solution

[0005] A wide range high-precision flow control system, comprising: a large flow pump assembly, a small flow pump assembly, an intermediate pipeline, a large flow regulating pipeline, a small flow regulating pipeline, a control unit, and an oil outlet pipeline;

[0006] One end of the large flow pump assembly and the small flow pump assembly is connected to the oil tank, and the other end is connected to one end of the intermediate pipeline;

[0007] One end of the large flow regulating pipeline and the small flow regulating pipeline is connected to the middle pipeline, and the other end is connected to the oil outlet pipeline;

[0008] The control unit connects and controls the large flow pump assembly, the small flow pump assembly, the large flow regulating pipeline, and the small flow regulating pipeline.

[0009] Furthermore, the large flow pump assembly includes a large flow pump, a shock absorbing hose and an oil filter which are connected in sequence, and the large flow pump outputs a flow rate Q1 of 20L / min to 450L / min.

[0010] Furthermore, the large flow pump assembly includes a small flow pump, a shock absorbing hose and an oil filter which are connected in sequence, and the small flow pump outputs a flow rate Q2 of 2L / min to 50L / min.

[0011] Further, the large-flow regulation pipeline includes a large flowmeter and a large proportional valve; the flow range Q3 of the large flowmeter is 50 L / min to 500 L / min; accuracy: class 0.5, error ±2.5 L / min; the control precision D1 of the large proportional valve is 2 L / min.

[0012] Further, the small-flow regulation pipeline includes a small flowmeter and a small proportional valve; the flow range Q4 of the small flowmeter is 5 L / min to 50 L / min; accuracy: class 0.5, error ±0.25 L / min; the control precision D2 of the small proportional valve is 0.2 L / min.

[0013] Further, a pressure gauge is provided on the oil outlet pipeline.

[0014] Further, there is one intermediate pipeline, and the oil from the large-flow pump assembly and the small-flow pump assembly first merges and then flows to the large-flow regulation pipeline and the small-flow regulation pipeline respectively.

[0015] Further, there are two intermediate pipelines, and the oil from the large-flow pump assembly and the small-flow pump assembly flows to the large-flow regulation pipeline and the small-flow regulation pipeline respectively.

[0016] 9 A wide-range high-precision flow control method is implemented through the said system, and the steps are as follows:

[0017] S1: Set the test flow rate and accuracy requirements;

[0018] S2: When the test flow rate ≤ Q2, enter S3, the small-flow control mode; when the test flow rate > Q2 and the accuracy requirement ≥ D2, enter S4, the large-flow regulation mode; when the test flow rate > Q2 and the accuracy requirement < D2, enter S5, the fine flow regulation mode;

[0019] S3: The control unit controls the small-flow pump and the small proportional valve to open, and closes the large-flow pump and the large proportional valve;

[0020] Collect the flow value of the small flowmeter, and control the opening of the small proportional valve through the PID algorithm;

[0021] S4: When the test flow rate is greater than Q2 but less than Q1, the control unit controls the large-flow pump and the large proportional valve to open, and closes the small-flow pump and the small proportional valve; collect the flow value of the large flowmeter, and control the opening of the large proportional valve through the PID algorithm;

[0022] When the test flow rate is greater than Q1 and less than Q1 + Q2, the control unit controls the large-flow pump, the small-flow pump, and the large proportional valve to open, and closes the small proportional valve; collect the flow value of the large flowmeter, and control the opening of the large proportional valve through the PID algorithm;

[0023] S5: When the test flow rate is greater than Q2 but less than Q1, the control unit controls the large flow pump, large proportional valve, and small proportional valve to open, and closes the small flow pump;

[0024] Divide the total test flow Q into QA+QB;

[0025] The target flow of the large proportional valve is QA, and the target flow of the small proportional valve is QB. The flow values ​​of the large and small flow meters are collected respectively, and the opening of the large and small proportional valves are controlled respectively through the PID algorithm;

[0026] When the test flow rate is greater than Q1 and less than Q1+Q2, the control unit controls the large flow pump, small flow pump, large proportional valve, and small proportional valve to open;

[0027] Divide the total test flow Q into QA+QB;

[0028] The target flow of the large proportional valve is QA, and the target flow of the small proportional valve is QB; the flow values ​​of the large and small flow meters are collected respectively, and the opening of the large and small proportional valves are controlled respectively through the PID algorithm.

[0029] Furthermore, the value range of QB is: Q4.

[0030] Beneficial effect: The flow control system of the present invention sets two adjustment loops with different flow ranges and designs reasonable overlapping intervals for different flow adjustment ranges, thereby further effectively avoiding dead zones (non-adjustable intervals) within the target adjustment flow range, thereby achieving the purpose of expanding the flow adjustment range and improving the flow adjustment accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention includes 2 drawings, and the drawings and the descriptions of the drawings are as follows:

[0032] Figure 1 This is a schematic diagram of the pipeline principle;

[0033] Figure 2 This is the control system schematic.

[0034] Among them: 1. Oil tank, 2. Large flow pump, 3. Small flow pump, 4. Shock absorber hose, 5. Oil filter, 6. Check valve, 7. Large flow meter, 8. Large proportional valve, 9. Small flow meter, 10. Small proportional valve, 11. Large flow regulating pipeline, 12. Small flow regulating pipeline, 13. Pressure gauge, 14. Control unit, 15. Test product. DETAILED DESCRIPTION

[0035] The flow control system is controlled by a PLC system. Two flow control loops are designed independently. The flow control loop uses parallel control to achieve different flow range adjustments. The control unit of the flow control system allocates the output flow of the flow control loop according to the flow setting range. The control unit collects the flow of the large / small flow meter and controls the proportional valve to open / close through the PID algorithm until the flow is adjusted to the set value, completing the control of the corresponding channel flow.

[0036] The oil suction ports of the large flow pump 2 and the small flow pump 3 are connected to the oil tank 1 respectively, and the outlets are connected to the shock absorbing hose 4, which is used to stabilize the output flow of the large flow pump 2 and the small flow pump 3. The outlet of the shock absorbing hose 4 is connected to the oil filter 5, and the one-way valve 6 is connected after the large flow pump 2 to prevent the oil from flowing back. The large flow pump 2 and the small flow pump 3 are output in parallel, and after returning to the main pipeline, they are divided into two different flow regulating pipelines: the large flow regulating pipeline 11 and the small flow regulating pipeline 12.

[0037] A large flow meter 7 and a large proportional valve 8 are installed on the large flow regulating pipeline 11, and a small flow meter 9 and a small proportional valve 10 are installed on the small flow regulating pipeline 12. The control unit 14 obtains the flow values ​​of the large flow meter 7 and the small flow meter 9, controls the valve opening of the large proportional valve 8 and the small proportional valve 10, and realizes the target flow control. After that, the oil outputs the oil with a stable flow through the flow regulating pipeline 11 and the small flow regulating pipeline 12, and returns to the oil tank 1 after passing through the test product 15.

[0038] Introduction to the main components in the flow control system:

[0039] The output flow of the large flow pump 2 is 20L / min~450L / min;

[0040] The output flow rate of the small flow pump 3 is 2L / min~50L / min;

[0041] Large flow meter 7 flow range 50L / min~500L / min; accuracy: 0.5 level (i.e. error ±2.5L / min); output signal 4mA~20mA.

[0042] Small flow meter 9 flow range 5L / min~50L / min; accuracy: 0.5 level (i.e. error ±0.25L / min); output signal 4mA~20mA.

[0043] The control accuracy of large proportional valve 8 is 2L / min;

[0044] The control accuracy of the small proportional valve 10 is 0.2L / min.

[0045] The flow regulation loop control modes can be divided into three types:

[0046] a) Small flow regulation control mode: the large flow regulation loop is closed, and the output flow is controlled by the small flow regulation loop;

[0047] b) Large flow regulation control mode: The control system determines whether the small flow regulation loop or the large flow regulation loop is working according to the set flow. Or it can adjust the two loops at the same time to output the flow together;

[0048] c) Precision flow regulation control mode: The control system adjusts and controls the flow output according to the set flow. The large flow regulation loop is responsible for the output flow; the small flow regulation loop is responsible for controlling the precision.

[0049] The test personnel set the flow rate and select the large flow pump 2 or the small flow pump 3 according to the set flow range. The control unit 14 allocates the flow control circuit according to the flow setting range. The test oil is output through the large flow pump 2 or the small flow pump 3, and the control unit 14 obtains the flow values ​​of the large flow meter 7 and the small flow meter 9. The control unit 14 adds the flow values ​​of the large flow meter 9 and the small flow meter 9 to obtain the total flow value, compares the total flow value with the set flow, and then controls the valve opening of the large proportional valve 8 and the small proportional valve 10 to achieve the target flow control. The specific control is as follows:

[0050] a) Small flow control mode: When the set flow rate is within the range of 2L / min to 50L / min, the tester only needs to start the small flow pump 3. The control unit 14 controls the large proportional valve 8 to close. The control unit 14 collects the flow value of the small flow meter 9, and controls the small proportional valve 10 to open or close through the PID algorithm until the flow rate is adjusted to the set value, thereby completing the flow control.

[0051] b) Large flow rate adjustment mode (50L / min~500L / min): When the flow rate accuracy is not required, the set flow rate is within the range of 50L / min~450L / min, and the tester only needs to start the large flow pump 2; if the set flow rate is within the range of 450L / min~500L / min, the tester needs to start the large flow pump 2 and the small flow pump 3 at the same time. Then the control unit 14 controls the small proportional valve 10 to close, and the control unit 14 collects the flow value of the large flow meter 7, and controls the large proportional valve 8 to open or close until the flow rate is adjusted to the set value, thereby completing the flow control.

[0052] c) Precision flow adjustment mode (50L / min~500L / min): When the set flow is within the range of 50L / min~500L / min, and high-precision flow adjustment is set. The control unit 14 will adjust the large proportional valve 8 and the small proportional valve 10 at the same time to control the flow output. The large flow adjustment loop is responsible for the output flow; the small flow adjustment loop is responsible for controlling the accuracy.

[0053] If 320L / min is set, the control unit 14 will automatically distribute the flow, with the large flow regulation loop outputting 300L / min and the small flow regulation loop outputting 20L / min. When the control unit 14 starts the distribution, both channels are closed at the same time. After that, the large flow regulation loop will work first, and the large proportional valve 8 will be adjusted to distribute the target flow (300L / min) to the loop to maintain the flow of the channel. Then adjust the small proportional valve 10 to achieve the precision control of the remaining flow. Finally, a stable wide-range, high-precision flow of oil is output and supplied to the test product 15 for testing.

[0054] When the tested product 15 requires a different flow rate during the test, it is only necessary to adjust the set flow rate, and the control unit 14 will complete the flow rate adjustment again according to the above process based on the flow rate change.

Claims

1. A wide range and high precision flow control system, characterized in that: Including: A large-flow pump assembly, a small-flow pump assembly, an intermediate pipeline, a large-flow regulation pipeline, a small-flow regulation pipeline, a control unit, and an oil outlet pipeline; One end of the large-flow pump assembly and the small-flow pump assembly is connected to the fuel tank, and the other end is connected to one end of the intermediate pipeline; One end of the large-flow regulation pipeline and the small-flow regulation pipeline is connected to the intermediate pipeline, and the other end is connected to the oil outlet pipeline; The control unit is connected to and controls the large-flow pump assembly, the small-flow pump assembly, the large-flow regulation pipeline, and the small-flow regulation pipeline.

2. The system according to claim 1, characterized in that: The large-flow pump assembly includes a large-flow pump, a shock-absorbing hose, and an oil filter connected in sequence. The output flow rate Q1 of the large-flow pump is 20 L / min to 450 L / min.

3. The system according to claim 2, characterized in that: The small-flow pump assembly includes a small-flow pump, a shock-absorbing hose, and an oil filter connected in sequence. The output flow rate Q2 of the small-flow pump is 2 L / min to 50 L / min.

4. The system according to claim 3, characterized in that: The large-flow regulation pipeline includes a large flowmeter and a large proportional valve; the flow range Q3 of the large flowmeter is 50 L / min to 500 L / min; Accuracy: Class 0.5, error ±2.5 L / min; the control accuracy D1 of the large proportional valve is 2 L / min.

5. The system according to claim 4, characterized in that: The small-flow regulation pipeline includes a small flowmeter and a small proportional valve; the flow range Q4 of the small flowmeter is 5 L / min to 50 L / min; Accuracy: Class 0.5, error ±0.25 L / min; the control accuracy D2 of the small proportional valve is 0.2 L / min.

6. The system according to claim 5, characterized in that: A pressure gauge is provided on the oil outlet pipeline.

7. The system according to claim 6, characterized in that: There is one intermediate pipeline. The oil from the large-flow pump assembly and the small-flow pump assembly first merges and then flows to the large-flow regulation pipeline and the small-flow regulation pipeline respectively.

8. The system according to claim 7, characterized in that: There are two intermediate pipelines. The oil from the large-flow pump assembly and the small-flow pump assembly flows to the large-flow regulation pipeline and the small-flow regulation pipeline respectively.

9. A wide range high precision flow control method, implemented by any of the above described systems, characterized in that: The steps are as follows: S1: Set the test flow rate and accuracy requirements; S2: When the test flow rate ≤ Q2, enter S3, the small-flow control mode; when the test flow rate > Q2 and the accuracy requirement ≥ D2, enter S4, the large-flow regulation mode; when the test flow rate > Q2 and the accuracy requirement < D2, enter S5, the fine-flow regulation mode; S3: The control unit controls the small-flow pump and the small proportional valve to open, and closes the large-flow pump and the large proportional valve; Collect the flow rate value of the small flowmeter, and control the opening of the small proportional valve through the PID algorithm; S4: When the test flow rate is greater than Q2 but less than Q1, the control unit controls the large-flow pump and the large proportional valve to open, and closes the small-flow pump and the small proportional valve; collect the flow rate value of the large flowmeter, and control the opening of the large proportional valve through the PID algorithm; When the test flow rate is greater than Q1 and less than Q1 + Q2, the control unit controls the large-flow pump, the small-flow pump, and the large proportional valve to open, and the small proportional valve to close; collect the flow rate value of the large flowmeter, and control the opening of the large proportional valve through the PID algorithm; S5: When the test flow rate is greater than Q2 but less than Q1, the control unit controls the large-flow pump, the large proportional valve, and the small proportional valve to open, and closes the small-flow pump; Divide the total test flow rate Q total into QA + QB; The target flow rate of the large proportional valve is QA, and the target flow rate of the small proportional valve is QB; collect the flow rate values of the large and small flowmeters respectively, and control the openings of the large and small proportional valves through the PID algorithm respectively; When the test flow rate is greater than Q1 and less than Q1+Q2, the control unit controls the large flow pump, small flow pump, large proportional valve, and small proportional valve to open; Divide the total test flow Q into QA+QB; The target flow of the large proportional valve is QA, and the target flow of the small proportional valve is QB; the flow values ​​of the large and small flow meters are collected respectively, and the opening of the large and small proportional valves are controlled respectively through the PID algorithm.

10. The method according to claim 9, characterized in that: The value range of QB is: Q4.

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