Intelligent shutdown method for last-stage flight section

Abstract

The invention provides a final-stage flight section intelligent shutdown method, comprehensively considers technical innovation and engineering feasibility, and provides a carrier rocket final-stage intelligent shutdown technology and architecture based on cooperative work of an on-rocket utilization system and a control system, an electrical system is a current existing on-rocket product, and matching of a new on-rocket product is not needed. According to the method, the reliability of judging the quality of the last-stage residual propellant is ensured through the reliability guarantee methods of determining the working process of the system, formulating the working time sequence of the system, designing the data transmission time between the systems, passing root and section mark words, formulating the judgment opportunity and criterion and the like, and the rail height is increased according to the residual amount of the last-stage propellant; the propellant consumption caused by satellite orbital transfer is reduced, and the on-orbit life of the satellite is prolonged.

Description

Technical Field

[0001] The present invention relates to a terminal flight segment intelligent shutdown method, and relates to an electrical system architecture and data definition and interaction between systems in the terminal flight segment intelligent shutdown technology, and belongs to the field of launch vehicle electrical overall design. Background Art

[0002] At present, most of the shutdown methods for the final stage of launch vehicles at home and abroad are guided shutdown, with the goal of reaching the predetermined orbit. When the onboard computer (flight control machine) determines that the rocket has reached the predetermined orbit, it controls the engine shutdown according to the flight sequence, and completes the flight mission after the rocket adjusts its attitude and the payload separates.

[0003] However, according to historical flight data and simulation analysis, taking a certain medium-sized launch vehicle as an example, after the final stage guidance is shut down, the remaining propellant is far greater than the unusable amount of propellant, and even higher than the propellant safety margin. Therefore, there is still a large carrying capacity to further raise the orbital altitude, reduce the propellant consumption caused by satellite orbit change, and increase the satellite's on-orbit life. At present, various types of launch vehicles at home and abroad still have technical defects in making full use of the remaining propellant. The mainstream launch vehicles still use the design margin to ensure that the remaining propellant meets the safety requirements for guidance shutdown, and the remaining propellant is not used; or the quality judgment method of the remaining propellant in the final stage is unreliable, resulting in a waste of design resources. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide an intelligent shutdown technology for the final flight stage, to achieve raising the orbital altitude according to the remaining amount of final stage propellant, to reduce the propellant consumption caused by satellite orbit change, and to increase the on-orbit life of the satellite.

[0005] The technical solution of the present invention is: a method for intelligent shutdown of the final stage flight stage, the electrical system architecture used includes: a utilization system and a control system, during which data is transmitted through an RS485 bus interface; the utilization system receives the liquid level sensor of the oxygen tank and the fuel tank on the launch vehicle and the liquid level converter of the final stage propellant liquid level data as input, and outputs it to the control system after calculation; the control system receives the data output by the utilization system, and sends the control command signal to the controlled unit after processing;

[0006] The intelligent shutdown methods for the final flight stage include:

[0007] After the system is used to complete the adjustment, the remaining propellant mass is calculated, and the remaining propellant mass and other related data are packaged in a fixed format and sent to the control system;

[0008] The control system calculates the propellant consumption per second based on the remaining propellant mass in a fixed cycle and determines whether the propellant consumption per second is within the normal deviation range;

[0009] The control system calculates the remaining propellant working time based on the second consumption data within the normal deviation range;

[0010] Iterative guidance is performed. In the calculation of the last remaining propellant working time before stopping iterative guidance, the control system makes a final judgment on whether to enter the extended-range trajectory and increase the apogee orbit altitude. If the judgment conditions are met, it switches to the corresponding extended-range trajectory. If the switching conditions are not met, the standard trajectory is maintained;

[0011] Standard trajectory at the final shutdown time Tk 末级关机 Shut down, extended range trajectory in Tk 末级关机 +T N Always turn off the power, T N It is the time difference between the flight time required for the rocket's final stage to reach the orbital altitude of the extended-range trajectory apogee and the flight time required to reach the orbital altitude of the standard trajectory apogee.

[0012] Preferably, the process of calculating the remaining propellant mass is:

[0013] The system uses the data of the liquid level sensor and the liquid level converter to complete the calculation of the remaining propellant liquid level;

[0014] The remaining propellant mass is calculated based on the remaining propellant liquid level combined with the propellant density and tank volume.

[0015] Preferably, the data transmission format when the remaining propellant mass and other related data are packaged in a fixed format and sent to the control system is specifically:

[0016] The first bit: frame header, agreed upon between systems;

[0017] The second bit: the root and node flag, indicating the root and node status of the liquid level sensor;

[0018] The third bit: timestamp, used for time synchronization between systems;

[0019] Fourth place: remaining mass of fuel tank propellant, used to calculate the flight time of remaining propellant in the fuel tank;

[0020] The fifth digit: the remaining mass of the oxygen tank propellant, which is used to calculate the flight time of the remaining propellant in the oxygen tank;

[0021] The sixth digit: cumulative sum, used for data verification and agreed upon between systems;

[0022] The seventh bit: frame end, agreed upon between systems.

[0023] Preferably, the control system's final judgment condition for whether to enter the extended-range trajectory and increase the apogee orbit altitude is that at least three of the five most recent calculated remaining propellant working times of the fuel tank and oxygen tank meet the requirements of a certain extended-range trajectory.

[0024] Preferably, in the calculation of the remaining propellant working time other than the last time before stopping the iterative guidance, the control system determines whether to enter the extended-range trajectory and increase the apogee orbit altitude, and updates the number of times a certain extended-range trajectory can be satisfied in the last five judgments after each calculation.

[0025] Preferably, the root and node flag character indicates whether the remaining propellant level of the utilization system has an inflection point in voltage due to discontinuity when passing through the level sensor during the descending process: when the root and node flag character indicates that the corresponding propellant has an inflection point, the data of the corresponding propellant is inaccurate;

[0026] The control system uses only the propellant mass data in the non-inflection point interval according to this flag word.

[0027] Preferably, the timestamp data is accumulated according to a fixed time period, and when the shutdown signals of various levels of the control system are received, the timestamp is cleared and accumulated again to ensure that the timestamp data will not overflow and be cleared.

[0028] Preferably, the remaining propellant mass includes: the remaining propellant mass of the fuel tank and the remaining propellant mass of the oxygen tank. The remaining propellant mass after the system stops adjusting is used when calculating the propellant consumption per second and the working time of the remaining propellant.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) The present invention ensures the reliability of the quality judgment of the remaining propellant in the final stage by clarifying the system working process, formulating the system working sequence, designing the data transmission time between systems, the root and node flags, formulating the judgment timing and criteria, etc., so as to achieve the orbit height increase according to the remaining propellant in the final stage, reduce the propellant consumption caused by the satellite orbit change, reduce resource waste, and increase the satellite's on-orbit life;

[0031] (2) The electrical systems of the present invention are all currently available products on the rocket, and there is no need to match new products on the rocket, thus saving design resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a diagram of the intelligent shutdown electrical system architecture of the present invention;

[0033] Figure 2 It is a diagram of the system working process of the present invention; DETAILED DESCRIPTION

[0034] The present invention proposes a method for intelligently shutting down the last stage of a launch vehicle based on the coordinated work of an onboard utilization system and a control system. The utilization system collects the height of the remaining propellant liquid level and calculates the remaining propellant mass and sends the relevant data to the control system. The control system calculates the working time of the remaining available propellant, determines the time for the launch vehicle to perform an extended-range flight based on the standard target orbit, and executes the corresponding shutdown sequence. On the basis of ensuring mission reliability, the orbital altitude is further raised, which is suitable for most flight missions where the payload cannot be directly put into orbit.

[0035] 1. System composition and architecture

[0036] According to the attached Figure 1 As shown in the intelligent shutdown electrical system architecture diagram, the system composition and architecture proposed by the present invention are as follows:

[0037] (1) With the liquid level data of the final-stage propellant such as the liquid level sensors and liquid level transducers of the oxygen tank and fuel tank on the launch vehicle as the system input and the controlled units such as the engine as the output object, the electrical system architecture of the final-stage intelligent shutdown technology proposed in the present invention includes a liquid level digital processor of the system, an onboard computer of the control system, and an RS485 bus interface connecting the liquid level digital processor and the onboard computer; the liquid level digital processor of the system receives the liquid level data of the final-stage propellant such as the liquid level sensors and liquid level transducers of the oxygen tank and fuel tank on the launch vehicle as input; after the onboard computer of the control system completes the processing, it acts on the final control command signal to the controlled units such as the engine.

[0038] (2) The liquid level digital processor utilized by the system, the arrow-borne computer of the control system, and the RS485 bus interface between systems are all currently existing arrow products, and the present invention does not require the matching of new arrow products.

[0039] 2. System Working Process

[0040] According to the attached Figure 2 As shown in the system working process diagram, the system working process proposed by the present invention is as follows:

[0041] (1) When the system ends the adjustment,

[0042] ① The system uses the data from the liquid level sensor and liquid level converter to calculate the remaining propellant liquid level;

[0043] ② Calculate the remaining propellant mass based on the remaining propellant liquid level, combined with the propellant density, tank volume, etc.;

[0044] ③ And send the data in the inter-system data transfer table shown in Table 1 to the control system through the RS485 interface;

[0045] ④ The control system uses a fixed period (e.g. 2s) to calculate the propellant consumption per second based on the remaining propellant mass, and determines whether the consumption per second is within the normal deviation range;

[0046] (2) Intelligent shutdown calculation stage: The control system calculates the remaining usable propellant working time based on the valid (i.e., within the normal deviation range) second consumption data, which serves as the judgment condition for whether the target orbit apogee can be switched to the corresponding extended-range ballistic trajectory altitude;

[0047] (3) Intelligent shutdown decision stage: Iterative guidance is performed. In the non-last calculation before stopping the iterative guidance, the control system determines whether to enter the extended-range trajectory and increase the apogee orbit altitude, and updates the number of times that a certain extended-range trajectory can be satisfied in the last five judgments after each calculation; in the last calculation of the remaining propellant working time before stopping the iterative guidance, the control system makes the final judgment on whether to enter the extended-range trajectory and increase the apogee orbit altitude. The judgment criterion is that at least three of the five most recent judgment results of the remaining propellant working time of the fuel tank and oxygen tank meet the requirements of a certain extended-range trajectory. If the judgment conditions are met, the corresponding extended-range trajectory will be switched. If the switching conditions are not met, the standard trajectory will be maintained.

[0048] (4) Shutdown stage: Standard trajectory at Tk 末级关机 Always shut down, extended range trajectory in Tk 末级关机 +T N Always turn off the power, T N It is the time difference between the flight time required for the rocket's final stage to reach the orbital altitude of the extended-range trajectory apogee and the flight time required to reach the orbital altitude of the standard trajectory apogee.

[0049] Table 1 Data transfer table between systems

[0050]

[0051]

[0052] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. A method for intelligent shutdown of the final flight segment, characterized in that include: The electrical system architecture used includes: utilizing system and control system, in which data is transmitted through RS485 bus interface; the utilizing system receives the liquid level sensor of oxygen tank and fuel tank on the launch vehicle and the liquid level data of the final stage propellant of the liquid level converter as input, and outputs it to the control system after calculation; the control system receives the data output by the utilizing system, and sends the control command signal to the controlled unit after processing; The intelligent shutdown methods for the final flight stage include: After the system is used to complete the adjustment, the remaining propellant mass is calculated, and the remaining propellant mass and other related data are packaged in a fixed format and sent to the control system; The control system calculates the propellant consumption per second based on the remaining propellant mass in a fixed cycle and determines whether the propellant consumption per second is within the normal deviation range; The control system calculates the remaining propellant working time based on the second consumption data within the normal deviation range; Iterative guidance is performed. In the calculation of the last remaining propellant working time before stopping iterative guidance, the control system makes a final judgment on whether to enter the extended-range trajectory and increase the apogee orbit altitude. If the judgment conditions are met, it switches to the corresponding extended-range trajectory. If the switching conditions are not met, the standard trajectory is maintained; Standard trajectory at the final shutdown time Tk 末级关机 Shut down, extended range trajectory in Tk 末级关机 +T N Always turn off the power, T N It is the time difference between the flight time required for the rocket's final stage to reach the orbital altitude of the extended-range trajectory apogee and the flight time required to reach the orbital altitude of the standard trajectory apogee.

2. A method for intelligent shutdown of the final flight segment according to claim 1, characterized in that: The procedure for calculating the remaining propellant mass is: The system uses the data of the liquid level sensor and the liquid level converter to complete the calculation of the remaining propellant liquid level; The remaining propellant mass is calculated based on the remaining propellant liquid level combined with the propellant density and tank volume.

3. The method for intelligent shutdown of the final flight segment according to claim 1, characterized in that: The data transmission format when the remaining propellant mass and other related data are packaged in a fixed format and sent to the control system is as follows: The first bit: frame header, agreed upon between systems; The second bit: the root and node flag, indicating the root and node status of the liquid level sensor; The third bit: timestamp, used for time synchronization between systems; Fourth place: remaining mass of fuel tank propellant, used to calculate the flight time of remaining propellant in the fuel tank; The fifth digit: the remaining mass of the oxygen tank propellant, which is used to calculate the flight time of the remaining propellant in the oxygen tank; The sixth digit: cumulative sum, used for data verification and agreed upon between systems; The seventh bit: frame end, agreed upon between systems.

4. The method for intelligent shutdown of the final flight segment according to claim 1, characterized in that: The control system's final judgment on whether to enter the extended-range trajectory and increase the apogee orbit altitude is based on the following conditions: at least three of the five most recent calculated remaining propellant working times of the fuel tank and oxygen tank meet the requirements of a certain extended-range trajectory.

5. The method for intelligent shutdown of the final flight segment according to claim 1, characterized in that: In the calculation of the remaining propellant's working time, which is not the last time before stopping the iterative guidance, the control system determines whether to enter the extended-range trajectory and increase the apogee orbit altitude, and updates the number of times a certain extended-range trajectory can be satisfied in the last five judgments after each calculation.

6. The method for intelligent shutdown of the final flight segment according to claim 3, characterized in that: The cross-root and cross-section flag indicates whether the remaining propellant level of the utilization system has an inflection point due to discontinuity when passing through the level sensor during the descending process: when the cross-root and cross-section flag indicates that the corresponding propellant has an inflection point, the data of the corresponding propellant is inaccurate; The control system uses only the propellant mass data in the non-inflection point interval according to this flag word.

7. The method for intelligent shutdown of the final flight segment according to claim 3, characterized in that: The timestamp data is accumulated at a fixed time period. When the shutdown signal of each level of the control system is received, the timestamp is cleared and accumulated again to ensure that the timestamp data will not overflow and be cleared.

8. The method for intelligent shutdown of the final flight segment according to claim 3, characterized in that: The remaining propellant mass includes: the remaining propellant mass of the fuel tank and the remaining propellant mass of the oxygen tank. The remaining propellant mass after the system stops adjusting is used when calculating the propellant consumption per second and the working time of the remaining propellant.

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