A fuel control system

Abstract

The present invention discloses a fuel control system, including: a data acquisition unit, used to collect analog data and digital data; a data processing unit, which performs data processing after the data acquisition unit completes data acquisition, including filtering, solving, recursion and correction processing; a data transmission unit, which is used to communicate with a flight control computer, including uploading analog data and digital data and specific identification to the flight control computer, and receiving downlink instructions from the flight control computer; and a fuel pump control unit, which performs analysis after the data transmission unit receives the control instructions sent by the flight control computer, and is used to control the main fuel pump and the auxiliary fuel pump. The system of the present invention calculates the fuel quantity and receives a low fuel quantity alarm signal when the fuel quantity is low, thereby realizing power supply control and power supply current monitoring of the main and auxiliary fuel pumps.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle flight control, and more specifically, to a fuel control system. Background Art

[0002] Since the UAV is unmanned during flight operations, a dedicated fuel control system needs to be designed to monitor the fuel temperature, fuel quantity, main and auxiliary fuel pump current, fuel pressure, fuel tank pressure and other parameters in real time, calculate the fuel quantity and receive the low fuel alarm signal when the fuel quantity is low, realize the power supply control and power supply current monitoring of the main and auxiliary fuel pumps, and ensure the flight safety of the UAV.

[0003] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0004] The present invention provides a fuel control system, which is an embedded software. The main control board is based on the TMS320F28335 processor and has the function of monitoring the status of the fuel system, including uploading the status information of the fuel system, receiving and parsing the control instructions of the flight control computer, starting and shutting down the main and auxiliary fuel pumps, and low oil level alarm.

[0005] The present invention provides a fuel control system, comprising:

[0006] A data acquisition unit, used for collecting analog data and digital data;

[0007] A data processing unit performs data processing after the data acquisition unit completes data acquisition, including filtering, solving, recursion and correction processing;

[0008] The data transmission unit is used to communicate with the flight control computer, including uploading analog data, digital data and specific identification to the flight control computer, and receiving downlink instructions from the flight control computer;

[0009] The oil pump control unit parses the control instructions sent by the flight control computer after the data transmission unit receives them, and is used to control the main oil pump and the auxiliary oil pump.

[0010] Furthermore, it also includes an initialization unit, which performs system initialization after the system is powered on, including system clock initialization, interrupt initialization, SCI initialization, timer initialization, SPI initialization, and GPIO initialization.

[0011] Furthermore, the initialization unit is used to perform initialization settings related to the DSP, initialization of status flags of other units and other data, and completion of serial port protocol settings.

[0012] Furthermore, it also includes a self-test unit, which determines whether self-test is required through a status flag bit. If self-test is required, a corresponding self-test program is executed after judging the serial port data flag bit, and the data is uploaded.

[0013] Further, the analog data includes main fuel pump current, auxiliary fuel pump current, fuel temperature, fuel pressure, main fuel tank fuel level, auxiliary fuel tank fuel level, and fuel tank pressure;

[0014] The digital data includes the main oil pump status, the auxiliary oil pump status and the low oil level alarm status, and the low oil level alarm status corresponds to the main oil tank.

[0015] Furthermore, the filtering process requires digital filtering of the collected analog data to improve the accuracy of the data.

[0016] Furthermore, the solving process needs to solve the collected analog data to obtain the actual representation value corresponding to each analog voltage value.

[0017] Furthermore, the recursive processing needs to recursively process the collected analog data and digital data;

[0018] The correction processing needs to make corresponding corrections to the analog data after recursion to meet the corresponding data resolution requirements.

[0019] Furthermore, the oil pump control unit completes the switching of the working states of the main oil pump and the auxiliary oil pump according to the four states of the main oil pump working, the auxiliary oil pump working, the dual oil pumps working and the dual oil pumps stopping working.

[0020] Furthermore, the data format transmitted by the data transmission unit is 8-bit data, one start bit, one stop bit, no parity check, and the checksum adopts byte XOR check; when multi-byte data is transmitted, the low byte is in front and the high byte is in the back; unsigned data is represented by original code, and signed data is processed in the form of data shift.

[0021] The fuel control system of the present invention receives control instructions of the flight control computer through a data communication serial port to realize the switch control of the main and auxiliary fuel pumps, and at the same time collects sensor data such as fuel temperature, fuel pressure, fuel tank pressure, main and auxiliary fuel pump currents, and main and auxiliary fuel tank oil quantities in the fuel system; collects fuel low oil level alarm signals; and uploads the above collected data to the flight control computer through the communication serial port.

[0022] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0024] Figure 1 An interface diagram of a fuel control system according to an embodiment of the present invention is shown.

[0025] Figure 2 A data collection distribution diagram of AD7606 of a fuel control system according to an embodiment of the present invention is shown.

[0026] Figure 3 A schematic diagram of a fuel control system according to an embodiment of the present invention is shown.

[0027] Figure 4 A self-check flow chart of a fuel control system according to an embodiment of the present invention is shown.

[0028] Figure 5 FIG. 4 shows an AD interruption flow chart of a fuel control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0030] The present invention discloses a fuel control system, which calculates the fuel quantity by monitoring parameters such as fuel temperature, main and auxiliary fuel quantity, main and auxiliary fuel pump current, fuel pressure, fuel tank pressure, etc., and receives a low fuel quantity alarm signal when the fuel quantity is low, thereby realizing power supply control and power supply current monitoring of the main and auxiliary fuel pumps. After the fuel control system is in operation, it first performs initialization and power-on self-test tasks, and sends corresponding monitoring and measurement information to the flight control computer when the self-test is normal.

[0031] Specifically, the present invention provides a fuel control system, comprising:

[0032] A data acquisition unit, used for collecting analog data and digital data;

[0033] A data processing unit performs data processing after the data acquisition unit completes data acquisition, including filtering, solving, recursion and correction processing;

[0034] The data transmission unit is used to communicate with the flight control computer, including uploading analog data, digital data and specific identification to the flight control computer, and receiving downlink instructions from the flight control computer;

[0035] The oil pump control unit parses the control instructions sent by the flight control computer after the data transmission unit receives them, and is used to control the main oil pump and the auxiliary oil pump.

[0036] Specifically, the fuel control system has units such as initialization, self-test, data acquisition, data processing, fuel pump control, and data transmission.

[0037] The initialization unit performs initialization after the system is powered on, including system clock initialization, interrupt initialization, SCI initialization, timer initialization, SPI initialization, GPIO initialization and other module initialization tasks. The main functional requirements are as follows:

[0038] a) Perform initialization settings related to DSP, such as system clock, timer, AD acquisition cycle, watchdog, SCI, SPI, etc.;

[0039] b) Initialization of status flags and other data of other modules;

[0040] c) Complete the serial port protocol settings, such as baud rate, start bit, data bit, parity check, etc.

[0041] The self-check unit determines whether self-check is needed through the status flag (FCUStatus). If self-check is needed, it will execute the corresponding self-check program and upload data after judging the serial port data flag (FCUUartStatus). Otherwise, it will enter the normal working mode.

[0042] After the power-on initialization and self-test function are completed, the data acquisition unit carries out analog and digital data acquisition tasks. Analog data acquisition includes 7 channels, including the main and auxiliary oil pump current, fuel temperature, fuel pressure, main and auxiliary oil volume, and fuel tank pressure. Among them, the main and auxiliary oil pump current acquisition is two channels, corresponding to the main oil pump and auxiliary oil pump respectively, and the main and auxiliary oil volume acquisition is two channels, corresponding to the main fuel tank and auxiliary fuel tank respectively. Digital quantity acquisition includes three channels of digital quantity acquisition, including the main and auxiliary oil pump status acquisition and low oil level alarm status acquisition. Among them, the main and auxiliary oil pump status acquisition is two channels, corresponding to the main oil pump and auxiliary oil pump respectively, and the low oil level alarm status acquisition is one channel, corresponding to the main fuel tank.

[0043] The data processing unit is executed after the data acquisition function is completed. The data processing function is divided into filtering function, solving function, recursive function and correction processing.

[0044] Specifically, the filtering process requires digital filtering of the collected analog data such as the main and auxiliary fuel pump currents, fuel temperature, fuel pressure, main and auxiliary fuel volumes, and fuel tank pressure to improve the accuracy of the data.

[0045] The solution processing requires solving the 7-channel data of analog data collected by the fuel control system, such as main and auxiliary fuel pump current, fuel temperature, fuel pressure, main and auxiliary fuel volume and fuel tank pressure, to obtain the actual representation value corresponding to each analog voltage value.

[0046] Recursive processing requires recursion of the 7-channel analog data and 3-channel digital data collected by the fuel controller to ensure the "smoothness" of the corresponding analog data and the accuracy of the digital data.

[0047] The correction processing requires corresponding correction of the analog data after recursion to achieve the corresponding data resolution requirements.

[0048] The fuel pump control unit analyzes the control command sent by the flight control computer after receiving it in the fuel control system, and then controls the main and auxiliary fuel pumps, including the four states of main fuel pump working, auxiliary fuel pump working, dual fuel pump working and dual fuel pump stopping. The fuel control system needs to switch the working state of the main and auxiliary fuel pumps based on these four states, and improve the control strategy according to the requirements of hardware error prevention control.

[0049] The data transmission unit is a communication between the fuel control system and the flight control computer through an RS422, including uplink and downlink communication. The fuel control system frames the analog data, digital data and specific identification, and uploads them to the flight control computer; after receiving the downlink command from the flight control computer, the fuel control system completes the work of distinguishing the identification code, receiving the command category word, receiving the command word and comparing the checksum.

[0050] Specifically, the data format is 8-bit data, one start bit, one stop bit, no parity check, and the checksum uses byte XOR check (including synchronization bytes, ID frame identification frames, etc.), and the baud rate is 19.2Kbps. When transmitting multi-byte data, it is agreed that the low byte is in front and the high byte is in the back; unsigned data is represented by original code, and signed data is processed in the form of data shift.

[0051] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to be limiting of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention may be combined with each other without conflict.

[0052] Reference Figure 1-5This embodiment provides a fuel control system, the system main control board is based on TMS320F28335, including power-on initialization function, self-test function, data acquisition function, filtering function, solution function, recursion function, correction function, fuel pump control function, and RS422 function.

[0053] The fuel control system of the present invention can collect 7-channel analog data of fuel temperature, fuel pressure, fuel tank pressure, main and auxiliary fuel quantities, and main and auxiliary fuel pump currents, as well as 3-channel discrete data of low fuel quantity alarm signal and main and auxiliary fuel pump status.

[0054] The fuel control system has an RS422 interface for data exchange with the flight control computer. The communication protocol uses 11 bytes for downlink and 39 bytes for uplink, and the communication baud rate is 19200bps.

[0055] The fuel control system is equipped with a main and auxiliary fuel pump current acquisition interface, which can collect the main and auxiliary fuel pump current data. The main and auxiliary fuel pump current data are located in the 0th and 1st channel data of the 8-channel AD acquisition channel. The data is converted into upload values ​​after solution, filtering, recursion and correction.

[0056] The fuel control system has a fuel temperature interface. The fuel temperature data is located in the 7th channel data collected by AD. After the temperature is collected by the temperature sensor, the collected voltage value is converted into a resistance value, and then converted into a temperature value through the corresponding solution formula, and then recursively and corrected before being converted into an upload value.

[0057] The fuel control system has a fuel quantity and low oil level alarm interface. The fuel quantity data is located in the 2nd and 4th channel data collected by AD. The 1# and 2# oil level signals (0~5V analog quantity) are output through the oil level measurement unit, and are converted into upload values ​​after solution, recursion and correction. The oil level measurement unit outputs a low oil level alarm signal (discrete quantity).

[0058] The fuel control system has a fuel pressure interface that can collect fuel pressure data. The fuel pressure data is located in the 6th channel data collected by AD. The pressure is measured by the fuel pressure sensor and converted into an upload value after solution, recursion and correction.

[0059] The fuel control system has a tank pressure interface that can collect tank pressure data. The tank pressure data is located in the 5th channel data collected by AD, and the pressure output is realized through the tank pressure sensor. After solution, recursion and correction, it is converted into an upload value.

[0060] The fuel control system has the main and auxiliary fuel pump status and control interface. The main and auxiliary fuel pump status are discrete quantities. The main and auxiliary fuel pump status are obtained through GPIO51 and GPIO55 in TMS320F28335, and the final signal is determined based on the digital recursive algorithm.

[0061] The fuel control system has a firmware interface, and the fuel control software is fixed into the Flash of TMS320F28335 through the Texas Instruments XDS100v3USB Emulator and the JTAG interface.

[0062] Specifically, the power-on initialization function is executed after the system is powered on, setting the system clock main frequency to 60MHz; setting the timer Timer0 interrupt period to 1ms; setting the AD acquisition to be triggered once every 2 ms, that is, an AD interrupt is triggered every 2 timer Timer0 interrupts; setting data to be uploaded to the flight control computer once every 500ms, that is, the data update rate is 2Hz; the watchdog restarts counting every 50ms; completes the initialization of the relevant status flag data and other data; completes the serial port protocol setting, the baud rate is set to 19200bps, 1 start bit, 8 data bits, and no parity bit.

[0063] The self-test function is executed after initialization is completed, such as Figure 4 As shown, the fuel controller software determines whether self-test is required through the status flag (FCUStatus). If self-test is required (FCUStatus==0), the corresponding self-test program is executed after judging the serial port data flag (FCUUartStatus) and the self-test information is uploaded (FCUUartStatus==0). Otherwise, it enters the normal working mode.

[0064] After the system is powered on and initialized, the data acquisition function Figure 2 and Figure 5 As shown in the figure, when the AD interrupt is triggered, the analog data is collected through the AD7606 16-bit 8-channel synchronous sampling analog-to-digital data acquisition system (DAS), and the data is received by the SPI FIFO of the TMS320F28335. When the data is written into the corresponding data queue (circular queue) AD1ScanQueue, it is converted into a voltage value, and the data collection work of the 7 channels is completed. The corresponding quantities of the 7-channel data collection are: main and auxiliary fuel pump current, fuel gauge 2, fuel gauge 1, fuel tank pressure, fuel pressure, and fuel temperature.

[0065] The filtering function is executed after the data collection is completed, mainly for processing the collected 7-channel analog data. Specifically, each channel in the collected AD1ScanQueue queue dequeues 50 groups of data and enters the AD1MiddleData queue. Then, the 50 groups of data of each channel in the queue are bubble sorted and the average value of the 12th to 37th groups of data is calculated (the data of the 0th to 11th groups and the 38th to 49th groups are removed to filter out the "burr" data), and finally the Average is queued into the AD1RealQueue circular queue.

[0066] After the AD collects the 7-channel analog data, the corresponding voltage value needs to be converted into the actual representation value of the corresponding quantity. This function is realized according to the corresponding quantity calculation formula. For example, in the fuel oil quantity calculation, the collected voltage value needs to be converted into the representation fuel quantity value according to the fuel quantity calculation formula. The calculation methods of other analog data are similar and will not be repeated here.

[0067] The recursive function processes the collected 8-channel analog data and 3-channel digital data. For analog data, after the Average is queued into AD1RealQueue, the average value of every 6 Averages is calculated again to obtain the ValueReturn return value, which can ensure the "smoothness" of the data. For the collected digital signal (1 or 0), the digital processing queue is FuelDataQueue_Digital. The length of this circular queue is 6. Every 5 groups of data are judged as 1 and 0. If the value is 1, the total value Cnt is increased by 1. If it is 0, the total value Cnt is reduced by 1. Finally, the result of the final signal recursion is judged by judging whether the value of Cnt is greater than or equal to 1.

[0068] The correction function is to perform final processing on the analog data, which is achieved through AD1DataCalculation_K[8] and AD1DataCalculation_B[8]. AD1DataCalculation_K[8] performs corresponding coefficient correction on the 8-channel analog data before uploading, and AD1DataCalculation_B[8] performs compensation on the 8-channel analog data before uploading to ensure the accuracy of the final uploaded data and meet the corresponding data resolution requirements.

[0069] After parsing the downlink instruction sent by the flight control computer, the oil pump control function parses the 8th to 10th bytes of the downlink data frame. This instruction belongs to the oil pump control instruction. The 8th, 9th and 10th byte instructions are exactly the same. 0xB1 indicates that the main oil pump is working, 0xB2 indicates that the auxiliary oil pump is working, 0xB3 indicates that the dual oil pumps are working, and 0xB4 indicates that the dual oil pumps stop working.

[0070] After completing data acquisition and the above processing, the data transmission function frames the data packet through SCI and uploads it. GPIO63 is set to SCI sending, and GPIO62 is set to SCI receiving. After the serial port interrupt of the fuel control system is triggered, it receives the downlink instruction issued by the flight control computer. First, it determines whether it is a frame header, that is, first determines whether the first byte is 0xEB. If the judgment result is correct, it determines whether the next byte is 0x90. If the judgment result is correct, it reads the subsequent data and uses 11 frame lengths as the judgment condition. After receiving 11 characters, the data is written to ReceiveData

[11] .

[0071] The system of the present invention calculates the fuel quantity and receives a low fuel quantity alarm signal when the fuel quantity is low, thereby realizing power supply control and power supply current monitoring of the main and auxiliary fuel pumps by monitoring parameters such as fuel temperature, main and auxiliary fuel quantity, main and auxiliary fuel pump current, fuel pressure, and fuel tank pressure. After the fuel control system is in operation, it first performs initialization and power-on self-test tasks, and sends corresponding monitoring and measurement information to the flight control computer when the self-test is normal.

[0072] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A fuel control system, characterized in that: include: A data acquisition unit, used to collect analog data and digital data, wherein the analog data includes the main fuel pump current, the auxiliary fuel pump current, the fuel temperature, the fuel pressure, the main fuel tank fuel level, the auxiliary fuel tank fuel level, and the fuel tank pressure, and the digital data includes the main fuel pump status, the auxiliary fuel pump status, and the low fuel level alarm status, wherein the low fuel level alarm status corresponds to the main fuel tank; A data processing unit performs data processing after the data acquisition unit completes data acquisition, including filtering processing, solving processing, recursive processing and correction processing. The filtering processing requires digital filtering of the collected analog data to improve the accuracy of the data. The solving processing requires solving the collected analog data to obtain the actual representation value corresponding to each analog voltage value. The recursive processing requires recursion of the collected analog data and digital data. The correction processing requires corresponding correction of the analog data after the recursive processing to meet the corresponding data resolution requirements. The data transmission unit is used to communicate with the flight control computer, including uploading analog data, digital data and specific identification to the flight control computer, and receiving downlink instructions from the flight control computer; The oil pump control unit is used to analyze the control instructions sent by the flight control computer after the data transmission unit receives them, and is used to control the main oil pump and the auxiliary oil pump; It also includes an initialization unit, which performs system initialization after the system is powered on, including system clock initialization, interrupt initialization, SCI initialization, timer initialization, SPI initialization, and GPIO initialization.

2. The fuel control system according to claim 1, characterized in that: The initialization unit is used to perform initialization settings related to the DSP, initialization of the status flags of other units and other data, and completion of serial port protocol settings.

3. The fuel control system according to claim 1, characterized in that: It also includes a self-test unit, which determines whether self-test is required through a status flag bit. If self-test is required, the corresponding self-test program is executed after judging the serial port data flag bit, and the data is uploaded.

4. The fuel control system according to claim 1, characterized in that: The oil pump control unit switches the working state of the main oil pump and the auxiliary oil pump according to the four states of the main oil pump working, the auxiliary oil pump working, the dual oil pump working and the dual oil pump stopping working.

5. The fuel control system according to claim 1, characterized in that: The data format transmitted by the data transmission unit is 8-bit data, one start bit, one stop bit, no parity check, and the checksum adopts byte XOR check; when multi-byte data is transmitted, the low byte is in front and the high byte is in the back; unsigned data is represented by original code, and signed data is processed in the form of data shift.

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