Carrier rocket propellant liquid level measurement filtering method based on volume extrapolation

Abstract

The invention relates to a carrier rocket propellant liquid level measurement filtering method based on volume extrapolation. The method comprises the steps that the current section number of a liquid level sensor is judged; adopting a triangular wave fitting method to calculate the liquid level height of a non-inflection point area; performing inflection point area liquid level height calculation by adopting a volume extrapolation method: if the current section number is an odd number, when the triangular wave voltage is smaller than Umin + deltaV for the first time, or if the current section number is an even number, and when the triangular wave voltage is larger than Umax-deltaV for the first time, performing least square fitting and extrapolating a volume trend line by utilizing the liquid level volume data within the time T0 before the moment, the volume data within the time Tw after the moment are all replaced by the data on the volume trend line, and finally the volume is inversely transformed back to the height value. According to the method, the problem of inflection point distortion is eliminated under the condition that the height calculation precision is not reduced, input information does not need to be externally connected, and the implementation mode is relatively simple.

Description

Technical Field

[0001] The invention belongs to the overall technical field of launch vehicles and relates to a launch vehicle propellant level measurement filtering method based on volume extrapolation. Background Art

[0002] Using liquid level sensor Figure 1 For the segmented capacitive sensor shown in the figure, when the liquid level passes through the node between two adjacent segments, the triangular wave voltage will produce an inflection point, and the height solution value will be distorted, causing it to jump, such as Figure 2 shown.

[0003] At present, the basic algorithm for continuous liquid level height calculation mainly includes three steps: node number determination, triangle wave fitting, and height calculation. The jump of liquid level height at the inflection point is mainly related to the current height calculation algorithm. The specific reasons are divided into two: the first is the time delay in determining the inflection point of the triangle wave voltage, and the second is the distortion caused by the fitting algorithm within a specific time after the inflection point is completed.

[0004] The above two reasons work together to cause the height solution value to deviate at the inflection point, which in turn causes it to jump.

[0005] The processing requirements of the liquid level triangle wave signal present the characteristics of alternating high and low pass. In the rising or falling section (i.e., non-inflection point section), it is expected to be as smooth as possible, that is, the algorithm presents a low-pass characteristic; at the inflection point, it is expected to complete the turning at the fastest speed, that is, present a high-pass characteristic. Due to the above contradictions, if the triangle wave is used as the object, no matter what single improved algorithm is used, it is destined to be unable to take into account both the low-pass characteristics of the non-inflection point area and the high-pass characteristics of the inflection point area. Summary of the invention

[0006] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a launch vehicle propellant level measurement filtering method based on volume extrapolation, so as to eliminate the inflection point distortion problem without reducing the height solution accuracy, and no external input information is required, and the implementation method is relatively simple.

[0007] The technical solution of the present invention is: a launch vehicle propellant level measurement filtering method based on volume extrapolation, comprising the following steps:

[0008] Determine the current number of sections of the liquid level sensor;

[0009] According to the results of node number identification, the triangle wave fitting method is used to calculate the liquid level height in the non-inflection point area;

[0010] According to the results of the number of nodes, the volume extrapolation method is used to calculate the liquid level height in the inflection point area, including:

[0011] If the current number of nodes is an odd number, when the triangle wave voltage is less than Umin +ΔV, or, if the current node number is an even number, when the triangle wave voltage is greater than U for the first time max When -ΔV, the liquid level volume data in the time T0 before this moment is used for least square fitting, and the volume trend line is extrapolated. The volume data in the time Tw after this moment are replaced by the data on the volume trend line, and finally the volume is inversely transformed back to the height value; where U max , U min are the maximum and minimum values ​​of the triangular wave voltage output by the liquid level sensor, and ΔV is the trigger mark point threshold.

[0012] Furthermore, the current number of nodes of the liquid level sensor is determined, including:

[0013] The first node determination starts at the preset flight time: the first node determination compares the relationship between the preset initial node number and the slope of the triangle wave signal: after the first node determination starts, a number of triangle wave voltage values ​​are continuously collected for linear fitting. If the slope fitting result is positive, it means that the current node number is an even number. If the slope fitting result is negative, it means that the current node number is an odd number. It is compared with the preset initial node number in the various parameters. If the parity is consistent, it is determined to be equal to the initial node number. If the parity is inconsistent, it is determined that the current node number is the initial node number minus one.

[0014] After completing the first section judgment, continue to perform subsequent section judgments: continue to collect a number of consecutive voltage data for linear fitting, and each time a positive or negative change in the slope is detected, the number of sections is reduced by 1 based on the number of the previous section.

[0015] Furthermore, a triangle wave fitting method is used to calculate the liquid level height in the non-inflection point area, including:

[0016] If the current number of nodes is an odd number, the triangle wave voltage is greater than U min When +ΔV, the height is calculated as follows:

[0017]

[0018] H=h+h0

[0019] The current number of nodes is an even number, and the triangle wave voltage is less than U max When -ΔV, the height is calculated as follows:

[0020]

[0021] H=h+h0

[0022] Where: N is the current number of liquid level sensors; H c is the length of each section of the liquid level sensor; h0 is the installation height of the liquid level sensor, U is the current fitting triangle wave voltage value; H 节间距is the distance between two adjacent sections of the liquid level sensor; h is the liquid level height value of the liquid level sensor, and H is the total liquid level height.

[0023] Furthermore, the trigger mark point threshold ΔV is based on the principle of covering the changes in the maximum and minimum voltages of the triangle wave during a flight, and the value is 0.1V to 0.3V.

[0024] Furthermore, the least squares fitting time T0 selects the landmark point U min +ΔV or U max The voltage data of 2s before -ΔV are fitted.

[0025] Furthermore, the extrapolated calculation interval Tw ranges from 5s to 7s.

[0026] Furthermore, the volume extrapolation method is not used before the first inflection point to ensure that the maximum and minimum voltages match.

[0027] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the launch vehicle propellant level measurement filtering method based on volume extrapolation are implemented.

[0028] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the launch vehicle propellant level measurement filtering method based on volume extrapolation are implemented.

[0029] A computer program product comprises a computer program, which, when executed by a processor, implements the steps of the launch vehicle propellant level measurement filtering method based on volume extrapolation.

[0030] The beneficial effects of the present invention compared with the prior art are:

[0031] (1) The present invention proposes a volume extrapolation-based launch vehicle propellant level measurement filtering method, which changes the algorithm optimization object from triangular wave to liquid level volume, and eliminates inflection point distortion without reducing the accuracy of height calculation by alternating the basic triangular wave calculation and the low-pass transformation based on liquid level height, volume or residual mass. Taking a certain type of rocket hydrogen-oxygen final stage as an example, Figure 6 The comparison results of the calculated value of the residual volume of hydrogen after adopting the improved algorithm of the present invention and the existing algorithm show that the improved algorithm obviously eliminates the jump at the node, and the transition after each extrapolation is more natural without a sharp drop or rise.

[0032] (2) The embodiment of the present invention realizes the switching of the algorithm by designing the least square fitting time and the extrapolation calculation interval, thereby improving the inflection point jump phenomenon. The least square fitting time selects the voltage data 2s before the mark point for fitting, which is sufficient to eliminate accidental errors and interference from liquid surface shaking; the extrapolation calculation interval ranges from 5s to 7s, which can take into account the low-pass characteristics of the non-inflection point area and the high-pass characteristics of the inflection point area. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the liquid level sensor and its nodes;

[0034] Figure 2 This is a schematic diagram of the liquid level height jump during the festival;

[0035] Figure 3 The schematic diagram of the filtering method for measuring the liquid level of a launch vehicle propellant based on volume extrapolation of the present invention is shown in FIG.

[0036] Figure 4 It is a schematic diagram of the marking points of the present invention;

[0037] Figure 5 The present invention is a flow chart of a launch vehicle propellant level measurement filtering method based on volume extrapolation;

[0038] Figure 6 This is a comparison chart between the liquid level measurement filtering method of the present invention and the results of the existing algorithm. DETAILED DESCRIPTION

[0039] The volume extrapolation-based filtering method for measuring the propellant level of a launch vehicle proposed in this invention changes the algorithm optimization object from triangular wave to liquid level volume, and eliminates the inflection point distortion without reducing the accuracy of height calculation by alternating the basic triangular wave calculation and the low-pass transformation based on liquid level height, volume or residual mass. The basic principle is as follows: Figure 3 shown.

[0040] like Figure 5 As shown, the propellant liquid level measurement filtering method of the present invention comprises the following steps:

[0041] Step 1: Determine the current number of nodes of the liquid level sensor;

[0042] Step 2: According to the result of node number identification, the triangle wave fitting method is used to calculate the liquid level height in the non-inflection point area:

[0043] If the current number of nodes is an odd number, the triangle wave voltage is greater than U min When +ΔV, the height is calculated as follows:

[0044]

[0045] H=h+h0

[0046] The current number of nodes is an even number, and the triangle wave voltage is less than U max When -ΔV, the height is calculated as follows:

[0047]

[0048] H=h+h0

[0049] Where: ΔV is the trigger mark threshold, N is the current number of liquid level sensor nodes; H c is the length of each section of the liquid level sensor; h0 is the installation height of the liquid level sensor, U is the current fitting triangle wave voltage value; U max The maximum value of the triangle wave voltage output by the liquid level sensor; U min H is the minimum value of the triangle wave voltage output by the liquid level sensor; 节间距 is the distance between two adjacent sections of the liquid level sensor; h is the liquid level height value of the liquid level sensor, and H is the total liquid level height.

[0050] Step 3: Based on the results of the number of nodes, the volume extrapolation method is used to calculate the liquid level height in the inflection point area:

[0051] If the current number of nodes is an odd number, when the triangle wave voltage is less than U min +ΔV, or, if the current node number is an even number, when the triangle wave voltage is greater than U for the first time max When -ΔV is reached, the liquid level volume data within T0 time before this moment is used for least squares fitting to extrapolate the volume trend line. The volume data within Tw time after this moment are replaced by the data on the volume trend line, and finally the volume is inversely transformed back to the height value.

[0052] The present invention will be further described below in conjunction with the embodiments.

[0053] Example 1

[0054] Step 1: Determine the current number of sections of the liquid level sensor.

[0055] The first segment judgment starts at the preset flight time: The first segment judgment mainly compares the relationship between the preset initial segment number and the slope of the triangle wave signal: After the first segment judgment starts, 70 triangle wave voltage values ​​(i.e. 7 seconds) are continuously collected for linear fitting. If the slope fitting result is positive, it means that the current number of segments is an even number. If the slope fitting result is negative, it means that the current number of segments is an odd number, which is compared with the preset initial number of segments in the various parameters. If the parity is consistent, it is judged to be equal to the initial number of segments. If the parity is inconsistent, it is judged that the current number of segments is the initial number of segments minus one.

[0056] After completing the first section judgment, continue to perform subsequent section judgments: continue to collect 40 consecutive voltage data for linear fitting, and each time a positive or negative change in the slope is detected, the number of sections is reduced by 1 based on the number of the previous section.

[0057] Step 2: According to the result of node number identification, the liquid level height in the non-inflection point area is calculated using the triangle wave fitting method.

[0058] Select U in the rising section of the liquid level triangle wave signal max -ΔV is the trigger mark point, and U is selected in the descending section of the liquid level triangle wave signal. min +ΔV is the trigger mark point;

[0059] If the current number of nodes is an odd number, the triangle wave voltage is greater than U min When +ΔV, the height is calculated as follows:

[0060]

[0061] H=h+h0

[0062] The current number of nodes is an even number, and the triangle wave voltage is less than U max When -ΔV, the height is calculated as follows:

[0063]

[0064] H=h+h0

[0065] Where: ΔV is the trigger mark threshold, N is the current number of liquid level sensor nodes; H c is the length of each section of the liquid level sensor; h0 is the installation height of the liquid level sensor, U is the current fitting triangle wave voltage value; U max The maximum value of the triangle wave voltage output by the liquid level sensor; U min H is the minimum value of the triangle wave voltage output by the liquid level sensor; 节间距 is the distance between two adjacent sections of the liquid level sensor; h is the liquid level height value of the liquid level sensor, and H is the total liquid level height.

[0066] The current fitting triangle wave voltage value U is calculated as follows: 40 consecutive voltage values ​​before the current time t are taken for linear fitting, the slope and intercept of the interval are obtained, and the fitting voltage value at time t is calculated.

[0067] Among them, the design of the extrapolation trigger mark point is specifically as follows:

[0068] Combined with the structure of the liquid level sensor and the characteristics of the liquid level signal, the maximum value of the triangular wave voltage output by the liquid level sensor is selected. max -ΔV (even nodes) or minimum value U min +ΔV (odd nodes) is used as the extrapolation trigger mark point. The selection of ΔV can be 0.1V~0.3V, in principle, to cover the maximum and minimum voltage changes of the triangle wave in a flight, such as Figure 4 shown.

[0069] Step 3: Based on the results of the number of nodes, the volume extrapolation method is used to calculate the liquid level height in the inflection point area:

[0070] If the current number of nodes is an odd number, when the triangle wave voltage is less than U min When +ΔV, the liquid level volume data within the time T0 before this moment is used for least squares fitting to extrapolate the volume trend line. The volume data within the time Tw after this moment are replaced by the data on the volume trend line, and finally the volume is inversely transformed back to the height value.

[0071] If the current number of nodes is an even number, when the triangle wave voltage is greater than U max When -ΔV is reached, the liquid level volume data within T0 time before this moment is used for least squares fitting to extrapolate the volume trend line. The volume data within Tw time after this moment are replaced by the data on the volume trend line, and finally the volume is inversely transformed back to the height value.

[0072] Among them, the design of the least square fitting time T0 is specifically as follows:

[0073] The least squares fitting time is the length of volume data used for extrapolation calculation after reaching the mark point. The least squares fitting time selects the voltage data 2s before the mark point for fitting, which is sufficient to eliminate accidental errors and interference from liquid surface shaking.

[0074] The design of the extrapolation calculation interval Tw is specifically as follows:

[0075] The extrapolation calculation interval refers to the time that the extrapolation calculation needs to last after the mark point. The extrapolation calculation interval Tw ranges from 5s to 7s, which can take into account the low-pass characteristics of the non-inflection point area and the high-pass characteristics of the inflection point area. This embodiment uses the extrapolation calculation interval that switches back to the triangle wave fitting algorithm after extrapolating for 5s.

[0076] The extrapolation optimization algorithm is not applied before the first inflection point to ensure that the maximum and minimum voltages match.

[0077] Taking a certain type of rocket hydrogen-oxygen final stage as an example, Figure 6 The comparison results of the calculated value of the residual volume of hydrogen after adopting the improved algorithm of the present invention and the existing algorithm are shown in Figure 1. It can be seen that the improved algorithm significantly eliminates the jump at the node, and the transition after each extrapolation is relatively natural without a significant drop or rise.

[0078] The present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer executes Figure 5 The method described.

[0079] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0080] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0081] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0082] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0084] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A launch vehicle propellant level measurement filtering method based on volume extrapolation, characterized in that: The following steps are involved: Determine the current number of sections of the liquid level sensor; According to the results of node number identification, the triangle wave fitting method is used to calculate the liquid level height in the non-inflection point area; According to the results of the number of nodes, the volume extrapolation method is used to calculate the liquid level height in the inflection point area, including: If the current number of nodes is an odd number, when the triangle wave voltage is less than U min +ΔV, or, if the current node number is an even number, when the triangle wave voltage is greater than U for the first time max When -ΔV, the liquid level volume data in the time T0 before this moment is used for least square fitting, and the volume trend line is extrapolated. The volume data in the time Tw after this moment are replaced by the data on the volume trend line, and finally the volume is inversely transformed back to the height value; where U max , U min are the maximum and minimum values ​​of the triangular wave voltage output by the liquid level sensor, and ΔV is the trigger mark point threshold.

2. The launch vehicle propellant level measurement filtering method based on volume extrapolation according to claim 1 is characterized in that: Determine the current number of sections of the liquid level sensor, including: The first node determination starts at the preset flight time: the first node determination compares the relationship between the preset initial node number and the slope of the triangle wave signal: after the first node determination starts, a number of triangle wave voltage values ​​are continuously collected for linear fitting. If the slope fitting result is positive, it means that the current node number is an even number. If the slope fitting result is negative, it means that the current node number is an odd number. It is compared with the preset initial node number in the various parameters. If the parity is consistent, it is determined to be equal to the initial node number. If the parity is inconsistent, it is determined that the current node number is the initial node number minus one. After completing the first section judgment, continue to perform subsequent section judgments: continue to collect a number of consecutive voltage data for linear fitting, and each time a positive or negative change in the slope is detected, the number of sections is reduced by 1 based on the number of the previous section.

3. The launch vehicle propellant level measurement filtering method based on volume extrapolation according to claim 1 is characterized in that: The triangle wave fitting method is used to calculate the liquid level height in the non-inflection point area, including: If the current number of nodes is an odd number, the triangle wave voltage is greater than U min When +ΔV, the height is calculated as follows: H=h+h0 The current number of nodes is an even number, and the triangle wave voltage is less than U max When -ΔV, the height is calculated as follows: H=h+h0 Where: N is the current number of liquid level sensors; H c is the length of each section of the liquid level sensor; h0 is the installation height of the liquid level sensor, U is the current fitting triangle wave voltage value; H 节间距 is the distance between two adjacent sections of the liquid level sensor; h is the liquid level height value of the liquid level sensor, and H is the total liquid level height.

4. The launch vehicle propellant level measurement filtering method based on volume extrapolation according to claim 1 is characterized in that: The trigger mark point threshold ΔV is based on the principle of covering the changes in the maximum and minimum voltages of the triangle wave during a flight, and its value is 0.1V~0.3V.

5. The launch vehicle propellant level measurement filtering method based on volume extrapolation according to claim 1 is characterized in that: The least squares fitting time T0 selects the landmark point U min +ΔV or U max The voltage data of 2s before -ΔV were fitted.

6. The launch vehicle propellant level measurement filtering method based on volume extrapolation according to claim 1 is characterized in that: The extrapolation calculation interval Tw ranges from 5s to 7s.

7. The launch vehicle propellant level measurement filtering method based on volume extrapolation according to claim 1 is characterized in that: No volume extrapolation is used before the first inflection point to ensure that the maximum and minimum voltages match.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method described in any one of claims 1 to 7 are implemented.

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