An engine state acquisition circuit

Abstract

The application discloses an engine state acquisition circuit, and relates to the technical field of electronic circuits, comprising a temperature acquisition circuit, a pressure acquisition circuit, a valve position acquisition circuit and a rotating speed acquisition circuit, wherein the circuits are provided with two paths; a main controller circuit comprising a main controller, wherein an estimation model is arranged in the main controller, the estimation model is used for calculating virtual data, two paths of data are selected in a two-out-of-three mode from two paths of actual data and one path of virtual data, and an average value is calculated as final state data. The virtual state data is calculated in a software simulation mode through the estimation model built in the main controller, so that the data redundancy design requirement of two-out-of-three is met, and the requirement for the main controller and power supply is effectively reduced.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to circuits for acquiring status data of rocket engines. Background Technology

[0002] As the core power unit for space launch missions, the accurate monitoring of the rocket engine's operating status directly determines the success or failure of the launch. Under extreme operating conditions (combustion chamber temperature of 3000℃+, gas pressure of 20MPa+, vibration acceleration of 100g+, wide temperature range of -55℃ to 125℃), strict resource constraints (onboard power supply ≤10W, communication bandwidth less than a few Mbps, and strict control of payload weight), and zero-fault-tolerance reliability requirements, the data acquisition system must break through conventional design logic to achieve the core objectives of accurate acquisition, reliable processing, and safe transmission.

[0003] To achieve this goal, current standards require redundant design in the data acquisition circuits. This means that multiple acquisition circuits simultaneously collect status data, and then at least two data points are selected to determine the final status data. Generally, at least three acquisition circuits are needed, using a "two-out-of-three" voting method to select the most reliable status data, ensuring reliable data acquisition even if some acquisition circuits fail. Currently, most acquisition circuits obtain status data using pure circuit methods. Setting up multiple redundant acquisition circuits requires a high-performance main controller and demanding power supply capabilities, which impacts the deployment and practical use of the acquisition circuits. Summary of the Invention

[0004] This application provides an engine status acquisition circuit to solve the problem that the requirements for main control and power supply are relatively high when using multi-channel pure acquisition circuits in the prior art.

[0005] This application provides an engine status acquisition circuit, including: The temperature acquisition circuit is set up with two channels, and the two temperature acquisition circuits respectively collect the actual temperature data of the rocket engine. The pressure acquisition circuit is equipped with two channels, which separately acquire the actual pressure data of the rocket engine. The valve position acquisition circuit is equipped with two channels, which respectively acquire the actual valve position data of the rocket engine. The rotational speed acquisition circuit is equipped with two channels, which respectively acquire the actual rotational speed data of the rocket engine. The main controller circuit is connected to the temperature acquisition circuit, pressure acquisition circuit, valve position acquisition circuit, and speed acquisition circuit. The main controller circuit includes the main controller, which deploys an estimation model. The main controller acquires actual temperature data, actual pressure data, actual valve position data, and actual speed data. The estimation model calculates corresponding virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data based on the actual temperature data, actual pressure data, actual valve position data, and actual speed data. It selects two data sources from two actual temperature data, actual pressure data, actual valve position data, and actual speed data, and one virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data in a three-out-of-two manner, calculates the average value of the two data sources, and uses it as the final state data. The RS422 communication circuit is connected to the main controller circuit and is used to send status data to the ground control center.

[0006] An engine status acquisition circuit according to this application has the following advantages: After the two acquisition circuits collect actual state data in a redundant manner, the virtual state data is calculated by software simulation through the estimation model built into the main controller. Finally, the reliable state data is determined by a two-out-of-three voting method. This two-real-one-virtual data acquisition method not only meets the two-out-of-three data redundancy design requirements, but also effectively reduces the requirements for the main controller and power supply. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 The circuit diagram of the main controller circuit and RS422 communication circuit in an engine status acquisition circuit provided in this application embodiment is shown.

[0009] Figure 2 A circuit diagram of the analog-to-digital conversion circuit provided in the embodiments of this application.

[0010] Figure 3 A circuit diagram of the temperature acquisition circuit provided in the embodiments of this application.

[0011] Figure 4 A circuit diagram of the valve position acquisition circuit provided in the embodiments of this application.

[0012] Figure 5The circuit diagram is provided for the speed acquisition circuit in the embodiment of this application.

[0013] Figure 6 A circuit diagram of the pressure acquisition circuit provided in the embodiments of this application. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] Figure 1-6 A circuit diagram of an engine status acquisition circuit provided in an embodiment of this application. An embodiment of this application provides an engine status acquisition circuit, including: The temperature acquisition circuit is set up with two channels, and the two temperature acquisition circuits respectively collect the actual temperature data of the rocket engine. The pressure acquisition circuit is equipped with two channels, which separately acquire the actual pressure data of the rocket engine. The valve position acquisition circuit is equipped with two channels, which respectively acquire the actual valve position data of the rocket engine. The rotational speed acquisition circuit is equipped with two channels, which respectively acquire the actual rotational speed data of the rocket engine. The main controller circuit is connected to the temperature acquisition circuit, pressure acquisition circuit, valve position acquisition circuit, and speed acquisition circuit. The main controller circuit includes the main controller, which deploys an estimation model. The main controller acquires actual temperature data, actual pressure data, actual valve position data, and actual speed data. The estimation model calculates corresponding virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data based on the actual temperature data, actual pressure data, actual valve position data, and actual speed data. It selects two data sources from two actual temperature data, actual pressure data, actual valve position data, and actual speed data, and one virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data in a three-out-of-two manner, calculates the average value of the two data sources, and uses it as the final state data. The RS422 communication circuit is connected to the main controller circuit and is used to send status data to the ground control center.

[0016] For example, the temperature acquisition circuit includes a temperature sensor and a temperature conditioning circuit connected in sequence; the pressure acquisition circuit includes a pressure sensor and a pressure signal conditioning circuit connected in sequence; the valve position acquisition circuit includes a valve position switch and a valve position signal conditioning circuit connected in sequence; and the speed acquisition circuit includes a speed sensor and a speed conditioning circuit connected in sequence.

[0017] Specifically, temperature sensors are installed at the engine exhaust port and on the combustion chamber wall, converting temperatures from 0 to 1800°C into a 0 to 75mV temperature signal. Pressure sensors are installed in the combustion chamber and fuel lines, converting pressures from 5 to 25MPa into a 0.5 to 4.5V pressure signal. A speed sensor is installed at the turbine shaft end, detecting changes in gear magnetic flux and outputting a pulse signal with a frequency proportional to the rotational speed, where 0 to 12000 rpm corresponds to 1Hz to 1kHz. A valve position switch is mechanically linked to the fuel valve, converting the 0 to 100% opening degree into a 0 to 5V linear voltage signal. Two redundant acquisition circuits synchronously acquire data, ensuring parallel acquisition and independence of the raw signals.

[0018] The engine status acquisition circuit in this embodiment further includes an analog-to-digital converter circuit. The input terminals of the analog-to-digital converter circuit are respectively connected to the temperature acquisition circuit, the pressure acquisition circuit, the valve position acquisition circuit, and the speed acquisition circuit. The output terminal of the analog-to-digital converter circuit is connected to the main controller circuit.

[0019] exist Figure 1-6 In this chip, D1 is an RS422 communication chip, D2 is the main controller, D3 is a storage chip, D4 is an analog-to-digital converter chip, U1 and U3 are both signal conditioning chips, U2A and U2B are both optocouplers, and U4A and U4B are both operational amplifiers.

[0020] Furthermore, the estimation model obtains virtual pressure data by weighted summation of actual valve position data and actual rotational speed data; obtains virtual temperature data by weighted summation of actual pressure data and actual rotational speed data; obtains virtual rotational speed data by weighted summation of actual pressure data and actual valve position data; and obtains virtual valve position data by weighted summation of actual pressure data and actual rotational speed data.

[0021] Specifically, pressure is a core parameter of the engine, which is strongly coupled with valve position and engine speed. The input variable is the average of two actual valve position data. V avg and the average of the two actual speed data N avg The output is virtual pressure data. P est Temperature is strongly coupled with pressure and rotational speed; the input variable is the average of two actual pressure data streams. P avg and the average of the two actual speed data N avgThe output is virtual temperature data. T est Rotational speed is strongly coupled with pressure and valve position; the input variable is the average of two actual pressure data streams. P avg and the average of the two actual valve position data V avg The output is virtual speed data. N est The valve position is strongly coupled with pressure and speed; the input variable is the average of two actual pressure data streams. P avg and the average of the two actual speed data N avg The output is virtual valve position data. V est .

[0022] Furthermore, before weighted summation, the main controller first obtains the operating temperature of the environment and corrects the weighting coefficients used in weighted summation based on the operating temperature.

[0023] Specifically, the main controller reads its own operating temperature through an onboard temperature sensor. T board Unit: °C, accuracy ±1 °C, range -55~125 °C, updated every 100ms. Temperature drift coefficient set to... α =0.0001 / ℃, this coefficient is obtained by fitting high and low temperature tests. For every 1℃ change in temperature, the coefficient needs to be corrected by 0.01%. Reference temperature T ref =25℃.

[0024] Furthermore, the main controller uses fixed-point arithmetic to correct the weighting coefficients and calculate virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data.

[0025] Specifically, all actual data are calculated into corresponding virtual data according to the following formula:

[0026] in, Y est For virtual data, K 1. K 2 and K 0 represents a weighting coefficient. X 1 and X 2 represents the actual data needed to calculate the virtual data.

[0027] The main controller corrects the coefficients according to the following formula:

[0028] in, K 1_real_int These are the corrected weighting coefficients; the original weighting coefficients are... K 1. K 2 and K 0 is obtained by least-squares fitting based on data from different operating conditions during ground testing. int 32 t The following number indicates that the data is a 32-bit integer, 65535 is the normalization coefficient, which corresponds to a 16-bit integer, and >>16 means shifting 16 bits to the right.

[0029] Similarly, the coefficients can be... K 2 and K 0 is corrected, and the corresponding result is obtained. K 2_real_int and K 0_real_int .

[0030] After the coefficients are corrected, the virtual data can be calculated using the following formula:

[0031] in, temp _ total For the intermediate data obtained from the calculation, X 1 norm and X 2 norm Normalized X 1 and X 2.

[0032] Furthermore, virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data in integer form are calculated using fixed-point arithmetic. During the calculation, the weighting coefficients are multiplied by 1000. After the calculation, the results are shifted 10 places to the right to obtain normalized estimated values, which are then converted into actual physical quantities.

[0033] Specifically, the shift and restore are performed according to the following formula:

[0034] in, Y est_norm For the restored data, ( uint 16 t The expression ) indicates that the following data is a 16-bit unsigned integer, and >>10 indicates a right shift of 10 bits.

[0035] In particular, if Y est_norm If <0, then set its value to 0. Y est_normIf the value is greater than 65535, set it to 65535 to avoid overflow during the calculation process.

[0036] Then, the normalized estimate is converted into the actual physical quantity according to the following formula:

[0037] in, Y max and Y min They are respectively Y est_norm The maximum and minimum values.

[0038] Furthermore, the weighting coefficients used in the weighted summation are related to the operating conditions of the rocket engine. The operating conditions are determined based on the actual rotational speed data. After determining the operating conditions based on the actual rotational speed data, the weighting coefficients corresponding to the operating conditions are read from the storage unit.

[0039] Specifically, in this embodiment, the rocket engine's operating conditions include a start-up phase, a steady-state phase, and a shutdown phase. The average actual engine speed data during the start-up phase... N avg <8000rpm, steady-state range 8000rpm≤ N avg ≤10000rpm, shutdown range N avg >10000rpm or N avg <7500rpm.

[0040] The following details the estimation process for pressure, temperature, valve position, and speed under different operating conditions.

[0041] 1. Combustion chamber pressure P Estimate.

[0042] (1) Start-up segment ( N avg <8000rpm) The estimation formula is as follows: P est_norm = K 1a × V norm + K 2a × N norm + K 0a ×1000>>10 Physical quantity conversion formula:

[0043] in, P est_norm This is a normalized estimate of the pressure. K 1a , K 2a and K 0a The weighting coefficients for the startup segment. V norm and N norm These are the normalized values ​​for valve position and rotational speed, respectively.

[0044] (2) Steady-state range (8000rpm≤ N avg ≤10000rpm) The estimation formula is as follows: P est_norm = K 1b × V norm + K 2b × N norm + K 0b ×1000>>10 in, K 1b , K 2b and K 0b These are the weighting coefficients for the steady-state phase. The physical quantity conversion formulas are the same as those for the startup phase.

[0045] (3) Shutdown segment ( N avg >10000rpm or N avg <7500rpm) The estimation formula is as follows: P est_norm = K 1c × V norm + K 2c × N norm + K 0c ×1000>>10 in, K 1c , K 2c and K 0cThis represents the weighting coefficient for the shutdown phase. The physical quantity conversion formula is the same as that for the startup phase.

[0046] 2. Exhaust temperature T Estimate.

[0047] (1) Start-up segment ( N avg <8000rpm) The estimation formula is as follows: T est_norm = K 3a × P norm + K 4a × N norm + K 5a ×1000>>10 Physical quantity conversion formula:

[0048] in, T est_norm This is a normalized estimate of the temperature. K 3a , K 4a and K 5a The weighting coefficients for the startup segment. P norm and N norm These are the normalized values ​​for pressure and rotational speed, respectively.

[0049] (2) Steady-state range (8000rpm≤ N avg ≤10000rpm) The estimation formula is as follows: T est_norm = K 3b × P norm + K 4b × N norm + K 5b ×1000>>10 in, K 3b , K 4b and K 5bThese are the weighting coefficients for the steady-state phase. The physical quantity conversion formulas are the same as those for the startup phase.

[0050] (3) Shutdown segment ( N avg >10000rpm or N avg <7500rpm) The estimation formula is as follows: T est_norm = K 3c × P norm + K 4c × N norm + K 5c ×1000>>10 in, K 3c , K 4c and K 5c This represents the weighting coefficient for the shutdown phase. The physical quantity conversion formula is the same as that for the startup phase.

[0051] 3. Engine speed N Estimate.

[0052] (1) Start-up segment ( N avg <8000rpm) The estimation formula is as follows: N est_norm = K 6a × P norm + K 7a × V norm + K 8a ×1000>>10 Physical quantity conversion formula:

[0053] in, N est_norm This is a normalized estimate of the rotational speed. K 6a , K 7a and K 8a The weighting coefficients for the startup segment. P norm andV norm These are the normalized values ​​for pressure and valve position, respectively.

[0054] (2) Steady-state range (8000rpm≤ N avg ≤10000rpm) The estimation formula is as follows: N est_norm = K 6b × P norm + K 7b × V norm + K 8b ×1000>>10 in, K 6b , K 7b and K 8b These are the weighting coefficients for the steady-state phase. The physical quantity conversion formulas are the same as those for the startup phase.

[0055] (3) Shutdown segment ( Navg >10000rpm or Navg <7500rpm) The estimation formula is as follows: N est_norm = K 6c × P norm + K 7c × V norm + K 8c ×1000>>10 in, K 6c , K 7c and K 8c This represents the weighting coefficient for the shutdown phase. The physical quantity conversion formula is the same as that for the startup phase.

[0056] 4. Valve opening degree V Estimate.

[0057] (1) Start-up segment ( N avg <8000rpm) The estimation formula is as follows: Vest_norm = K 9a × P norm + K 10a × N norm + K 11a ×1000>>10 Physical quantity conversion formula:

[0058] in, V est_norm This is a normalized estimate of the valve position. K 9a , K 10a and K 11a The weighting coefficients for the startup segment. P norm and N norm These are the normalized values ​​for pressure and rotational speed, respectively.

[0059] (2) Steady-state range (8000rpm≤ N avg ≤10000rpm) The estimation formula is as follows: V est_norm = K 9b × P norm + K 10b × N norm + K 11b ×1000>>10 in, K 9b , K 10b and K 11b These are the weighting coefficients for the steady-state phase. The physical quantity conversion formulas are the same as those for the startup phase.

[0060] (3) Shutdown segment ( N avg >10000rpm or N avg <7500rpm) The estimation formula is as follows: V est_norm = K9c × P norm + K 10c × N norm + K 11c ×1000>>10 in, K 9c , K 10c and K 11c This represents the weighting coefficient for the shutdown phase. The physical quantity conversion formula is the same as that for the startup phase.

[0061] Furthermore, after obtaining two channels of actual temperature data, actual pressure data, actual valve position data, and actual speed data, as well as one channel of virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data, the main controller first performs a pre-verification of data validity, and then performs a two-out-of-three voting based on different scenarios after the verification passes.

[0062] Specifically, a two-out-of-three vote will be conducted according to the following scenarios: All three channels are valid: take the data from the two channels whose deviations are less than the threshold; if the deviations of all three channels exceed the threshold, take the actual data. Two sets of actual data are valid, and virtual data is invalid: take the valid actual data and mark it as "model failed"; One channel of actual data is valid, and one channel of virtual data is valid: Take the two valid data channels and mark "one channel as hardware fault"; Only one channel of actual data is valid: retrieve the valid actual data and trigger the switchover to the backup channel; Virtual data only: Retrieve virtual data and send an emergency alarm; If all three channels are invalid: output historical data and mark it as "serious system failure".

[0063] After obtaining the voting results, the mean is calculated using fixed-point arithmetic and stored in the data buffer. The unique fault code corresponding to the fault type is stored in the fault register.

[0064] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0065] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. An engine status acquisition circuit, characterized in that, include: The temperature acquisition circuit is configured with two channels, which respectively acquire the actual temperature data of the rocket engine. The pressure acquisition circuit is equipped with two channels, which respectively acquire the actual pressure data of the rocket engine. The valve position acquisition circuit is equipped with two channels, and the two channels of the valve position acquisition circuit respectively acquire the actual valve position data of the rocket engine. The rotational speed acquisition circuit is configured with two channels, which respectively acquire the actual rotational speed data of the rocket engine. The main controller circuit is connected to the temperature acquisition circuit, the pressure acquisition circuit, the valve position acquisition circuit, and the speed acquisition circuit. The main controller circuit includes a main controller, which deploys an estimation model. The main controller acquires the actual temperature data, the actual pressure data, the actual valve position data, and the actual speed data. The estimation model calculates corresponding virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data based on the actual temperature data, actual pressure data, actual valve position data, and actual speed data. Two data sources are selected from two actual temperature data, actual pressure data, actual valve position data, and actual speed data, and one virtual temperature data, virtual pressure data, virtual valve position data, and virtual speed data, in a three-out-of-two manner. The average value of the two data sources is calculated as the final state data. An RS422 communication circuit is connected to the main controller circuit, and the RS422 communication circuit is used to send the status data to the ground control center.

2. The engine status acquisition circuit according to claim 1, characterized in that, The temperature acquisition circuit includes a temperature sensor and a temperature conditioning circuit connected in sequence; the pressure acquisition circuit includes a pressure sensor and a pressure signal conditioning circuit connected in sequence; the valve position acquisition circuit includes a valve position switch and a valve position signal conditioning circuit connected in sequence; and the speed acquisition circuit includes a speed sensor and a speed conditioning circuit connected in sequence.

3. The engine status acquisition circuit according to claim 1, characterized in that, It also includes an analog-to-digital converter circuit, the input terminals of which are respectively connected to the temperature acquisition circuit, the pressure acquisition circuit, the valve position acquisition circuit and the speed acquisition circuit, and the output terminal of which is connected to the main controller circuit.

4. The engine status acquisition circuit according to claim 1, characterized in that, The estimation model obtains the virtual pressure data by weighted summation of the actual valve position data and the actual rotational speed data; and obtains the virtual temperature data by weighted summation of the actual pressure data and the actual rotational speed data. The virtual rotational speed data is obtained by weighted summation of the actual pressure data and the actual valve position data; The virtual valve position data is obtained by weighted summation of the actual pressure data and the actual rotation speed data.

5. The engine status acquisition circuit according to claim 4, characterized in that, Before weighted summation, the main controller first obtains the operating temperature of the environment and corrects the weighting coefficients used in weighted summation based on the operating temperature.

6. The engine status acquisition circuit according to claim 4, characterized in that, The weighting coefficients used in the weighted summation are related to the operating conditions of the rocket engine, which are determined based on the actual rotational speed data. After determining the operating conditions based on the actual rotational speed data, the weighting coefficients corresponding to the operating conditions are read from the storage unit.

7. The engine status acquisition circuit according to claim 5, characterized in that, The main controller uses fixed-point arithmetic to correct the weighting coefficients and calculate the virtual temperature data, the virtual pressure data, the virtual valve position data, and the virtual speed data.

8. The engine status acquisition circuit according to claim 7, characterized in that, The virtual temperature data, virtual pressure data, virtual valve position data, and virtual rotation speed data are calculated in integer form using fixed-point arithmetic. During the calculation, the weighting coefficients are multiplied by 1000. After the calculation, the results are shifted 10 places to the right to obtain normalized estimated values, which are then converted into actual physical quantities.

9. The engine status acquisition circuit according to claim 1, characterized in that, After obtaining two channels of actual temperature data, actual pressure data, actual valve position data, and actual rotation speed data, as well as one channel of virtual temperature data, virtual pressure data, virtual valve position data, and virtual rotation speed data, the main controller first performs a data validity pre-verification, and then performs a two-out-of-three voting based on different scenarios after the verification passes.

10. An engine status acquisition circuit according to claim 9, characterized in that, A two-out-of-three vote will be conducted in the following scenarios: All three channels are valid: take the data from the two channels whose deviations are less than the threshold; if the deviations of all three channels exceed the threshold, take the actual data. If both sets of actual data are valid and the virtual data are invalid, then the valid actual data will be used. One channel of actual data is valid, and one channel of virtual data is valid: take the valid data from both channels. Only one channel of actual data is valid: only valid actual data is used; Only valid for virtual data: retrieve virtual data; All three channels are invalid: Output historical data.

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