CAN bus-based cargo loading fault isolation control method and system for cargo machine

Abstract

The invention relates to the technical field of aeronautical equipment and electronic information, in particular to a CAN bus-based cargo loading fault isolation control method for a cargo machine, which comprises the following steps of: entering a periodic self-checking process if the input of a'test 'control signal is not detected; judging whether the voltage or circuit sampling result exceeds a threshold value or not; the power driving unit sends a CAN message to the sub-control unit, message filtering and screening are carried out according to a message ID, and a bus where the power driving unit is located in the control area and the fault state of the power driving unit in the control area are judged; performing jitter removal processing on the'test 'control signal; detecting whether the'test 'control signal is valid or not again, if not, returning to periodic self-inspection, and if yes, keeping the current fault diagnosis result and sending the current fault diagnosis result to the main control unit; and the self-inspection is ended. The problem that the fault detection process of the power drive and control unit is tedious and complex is solved.

Description

Technical Field

[0001] The present invention relates to the fields of aviation equipment and electronic information technology, and more specifically, to a method and system for isolating and controlling cargo loading faults of a cargo aircraft based on the CAN bus. Background Art

[0002] At present, as a multi-master serial communication bus, the CAN bus has characteristics such as high transmission rate, high electromagnetic interference resistance, high real-time performance, and high reliability. In a single network composed of the CAN bus, theoretically, an infinite number of nodes can be mounted. Based on this characteristic, although the number of bus nodes is restricted by the electrical characteristics of network hardware in actual use, this bus form can still greatly reduce the required number of cables as a communication means between electronic control devices.

[0003] In the prior art, the cargo loading system of a cargo aircraft is installed in the cargo hold of the cargo aircraft to realize functions such as cargo loading matching detection, cargo power transmission, multi-directional cargo transmission, and locking of cargo during air transportation, and is composed of various electronic devices such as a control system, a cargo information detection device, a transmission device, a guiding device, and a locking device.

[0004] According to the above-mentioned related prior art, in some special application scenarios, such as a large number of nodes and non-concentrated distribution, more cables are actually required to realize communication between electronic devices, and at the same time, the difficulty of fault diagnosis is increased. When a fault occurs in the system, a one-by-one inspection on-site will consume a lot of time, and the fault detection process for the power drive and control units is relatively cumbersome and complex. If there are multiple faults and all the fault nodes cannot be isolated in time, the fault detection process will have cross-interference, and the detection will take a long time, which will have a great impact on the operation of the entire communication network. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the system fault detection process is cumbersome and complex, the fault detection processes of the power drive unit and the control unit have cross-interference, it takes a long time, and early warning of faults cannot be realized. In view of the above-mentioned defects of the prior art, a method and system for isolating and controlling cargo loading faults of a cargo aircraft based on the CAN bus are provided.

[0006] On the one hand

[0007] The technical solution adopted by the present invention to solve its technical problems is: A method for isolating and controlling cargo loading faults of a cargo aircraft based on the CAN bus, including

[0008] When it is detected that the external "test" signal is not activated, enter the periodic self-check process;

[0009] Judge whether the voltage or circuit sampling result exceeds the preset safety threshold;

[0010] Receive the messages sent by the power drive unit via the CAN bus, filter and screen the messages according to the message ID, and determine the bus where the power drive unit is located within the control area and the fault status of the power drive unit within the control area;

[0011] Debounce the "test" control signal;

[0012] Secondarily verify the validity of the "test" signal. If it is invalid, return to the periodic self-check. If it is valid, keep the current fault diagnosis result and send it to the main control unit;

[0013] End the self-check process.

[0014] Preferably, for the step of based on the power drive unit sending CAN messages to the sub-control unit, filtering and screening the messages according to the message ID, and judging the bus where the power drive unit is located within the control area and the fault status of the power drive unit within the control area, it includes:

[0015] Allocate the respective CAN message IDs to the main control unit, sub-control unit, and power drive unit; confirm the cross-link information, CAN message communication protocol, and fault isolation truth table between each unit;

[0016] Power on the device, output the effective control signals of all indicator lights, and the ADC and sensor acquisition circuits start to work;

[0017] Receive the messages sent by the drive control unit via the CAN bus, extract the ID and effective data content of the messages; obtain the sensor acquisition results in real time and poll each acquisition channel to obtain the ADC sampling values, and compare the ADC sampling results with the preset threshold range;

[0018] The time interval for the power drive unit to send CAN messages to the sub-control unit is t2, and filter and screen the messages according to the message ID;

[0019] For the bus where the power drive unit is located within the control area, if no message reported by any power drive unit on a bus is received within 10*t2 time, then the bus enters the fault state and the periodic self-check fails; if 10 valid messages are sent by the power drive units on the bus within 20*t2 in the fault state, the bus returns to normal.

[0020] Preferably, for the step of entering the periodic self-check process based on the non-detection of the "test" signal,

[0021] For the power drive unit within the control area, if no message reported by this unit is received within 10*t2 time, it is considered that this power drive unit enters the fault state and the periodic self-check fails; if there are 10 valid messages sent by this power drive unit within 20*t2 of this bus in the fault state, it is considered that this power drive unit returns to normal and the periodic self-check passes.

[0022] Preferably, it further includes a power-on self-check process; based on the steps of the power-on self-check process, it includes:

[0023] Filter and screen messages according to the message ID. For the bus where the power drive unit within the control area is located, if a message sent by any drive unit on this bus is retrieved, it is considered that the power-on self-check of this bus communication is normal, otherwise the power-on self-check result will remain in the non-passing state;

[0024] The power-on self-check results of the bus where the power drive unit within the control area is located and the voltage or current sampled by the ADC will be used as the CAN message data content. Combining with the message ID for the current sub-control unit to report self-check information allocated in the communication protocol, the message will be sent to the CAN interface.

[0025] Preferably, based on the steps of performing the power-on self-check, it includes:

[0026] When the voltage or circuit sampling result exceeds the threshold, start counting, and clear the count when it returns within the threshold range; when the count exceeds t0, the power-on self-check of this path of voltage or circuit fails;

[0027] The power-on self-check process ends, with a duration of t1, and t1 > 10*t0.

[0028] Preferably, based on the steps of debouncing the "test" control signal, it includes:

[0029] The control signal input continues to be held;

[0030] Terminate the detection of the input signals of controls other than "emergency brake" and "test", force the drive control circuit to start running for t3 time, and update the real-time fault state of the voltage or current at the time point of t3 / 2, and maintain this state until the end of t3 time;

[0031] Comprehensively based on the real-time acquisition results of the sensor, voltage or current, and the periodic self-check results of the CAN bus and the power drive unit, judge the fault nodes and fault states within the control area according to the fault truth table.

[0032] Preferably, based on the steps of judging whether the voltage or circuit sampling result exceeds the threshold, it includes:

[0033] If it exceeds, start counting. If it returns to the threshold range, clear the count. When the count exceeds t0, it is considered that the voltage or circuit cycle self-check of this path fails, and the failed state is continuously maintained until it returns to the normal threshold range and lasts for a duration of t1;

[0034] Based on the real-time acquisition results of the integrated sensor, voltage or current, and the cycle self-check results of the CAN bus and the power drive unit, judge the fault nodes and fault states in the control area according to the fault truth table, and send fault information to the main control unit at time intervals of t2.

[0035] On the other hand

[0036] A cargo aircraft cargo loading fault isolation control system based on the CAN bus, including a main control unit, a sub-control unit, and a power drive unit; the sub-control unit is used to provide a control signal to the drive control circuit, is connected to the main control unit and the power drive unit through the CAN bus, and receives the status information sent by the power drive unit and sends the comprehensively processed information to the main control unit;

[0037] The sub-control unit includes a control panel and an FPGA control circuit;

[0038] The control panel, a human-machine interaction panel, the digital signal output of the controls on the panel is connected to the discrete instruction module, and receives the electrical signal output from the status indication control module and converts it into an optical signal.

[0039] Preferably, the FPGA control circuit includes a discrete instruction recognition module, a status indication control module, a sensor acquisition module, an instruction processing module, a data processing module, an ADC acquisition module, a voltage and current detection module, a fault detection and isolation module, a serial port communication module, a configuration module, a communication self-check module, and a CAN interface module;

[0040] The discrete instruction recognition module, the input interface is connected to the external digital control, and outputs a control signal to the instruction processing module and the status indication control module;

[0041] The status indication control module, the input interface is connected to the discrete instruction recognition module and the instruction processing module, and the output interface is connected to the light-emitting part of the control panel;

[0042] The sensor acquisition module, outputs the sensor acquisition results to be connected to the instruction acquisition module;

[0043] The instruction processing module, the input interface is connected to the sensor acquisition module, the discrete instruction recognition module, the fault detection and isolation module, and the data processing module, and the output interface is connected to the status indication control module, the fault detection and isolation module, and the data processing module;

[0044] The data processing module, with its input interface connected to the CAN interface module and the instruction processing module, and its output interface connected to the CAN processing module and the instruction processing module;

[0045] The ADC acquisition module, which acquires analog signals and outputs them as digital signals to the voltage and current monitoring module after conversion;

[0046] The voltage and current monitoring module, which receives digital signals from the ADC acquisition module, receives threshold information from the configuration module, and outputs monitoring results to the fault monitoring and isolation module;

[0047] The fault detection and isolation module, with its input interface connected to the communication self-check module and the instruction processing module, and outputs the results of fault detection to the instruction processing module;

[0048] The serial communication module, which converts serial data into parallel data and outputs it to the configuration module, and converts parallel data from the configuration module into serial data and outputs it to the outside world;

[0049] The configuration module, with its input interface connected to the serial communication module, and outputs configuration information to the voltage and current monitoring module and the communication self-check module;

[0050] The communication self-check module, with its input interface connected to the CAN interface module and the configuration module, and its output interface connected to the fault detection and isolation module;

[0051] The CAN interface module, with its input and output interfaces connected to the CAN bus network, has two-way data interaction with the data processing module, and outputs messages to the communication self-check module.

[0052] Preferably, the cargo loading system of the cargo aircraft further includes a drive control circuit; the main control unit, which is an aggregate of a control computer and a main human-computer interaction interface, is connected to each sub-control unit through the CAN bus, issues instructions to the sub-control unit, receives feedback information from the sub-control unit, and displays the device operation status and fault information;

[0053] The drive control circuit is used to receive control signals from the sub-control unit and convert them into corresponding control actions;

[0054] The power drive unit, as the physical carrier of the controlled node, is controlled by the drive control circuit and is connected to the sub-control unit through the CAN bus.

[0055] The beneficial effects of the present invention are as follows: Different IDs are assigned to the power drive units and control units at different positions. The sub-control unit continuously integrates the operating states of different power drives and the states of drive circuits, comprehensively judges the specific fault positions and fault types, and periodically reports them to the main control unit, which improves the real-time performance of fault diagnosis while enhancing the accuracy of fault diagnosis and effectively reducing the system downtime. The effective test control signal of the sub-control unit control panel is collected, and the drive unit is forced to operate in the normal operation state. Fault diagnosis is carried out based on this simulated state, and pre-detection of some fault types can be realized, reducing the fault risk during system operation.

[0056] On the premise of retaining real-time performance, reduce the cables required for system communication to reduce costs, improve the accuracy of fault diagnosis, and provide a function to simulate a normal operation environment to achieve early warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will further illustrate the present invention in conjunction with the drawings and embodiments. The drawings in the following description are only partial embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts:

[0058] Figure 1 It is a schematic diagram of the structure of the goods transfer system assembled in the embodiment of the present application.

[0059] Figure 2 It is a schematic diagram of the functional modules of the control method in the embodiment of the present application.

[0060] Figure 3 It is an application example diagram of the cargo loading system of the cargo aircraft in the embodiment of the present application.

[0061] Figure 4 It is a schematic diagram of the connection structure of the control circuit in the embodiment of the present application.

[0062] Figure 5 It is a schematic diagram of the structure of the CAN message data frame format in the embodiment of the present application.

[0063] Figure 6 It is a schematic diagram of the serial communication frame format in the embodiment of the present application.

[0064] Figure 7 It is a schematic diagram of an example of the fault isolation truth table in the embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention. Apparently, the described embodiments are partial embodiments of the present invention rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0066] Embodiment 1

[0067] A preferred embodiment of the present invention includes a method for isolating and controlling faults in the cargo loading of a cargo aircraft based on the CAN bus, including:

[0068] Allocating the CAN message IDs belonging to the master control unit, sub-control unit, and power drive unit respectively; confirming the cross-link information, CAN message communication protocol, and fault isolation truth table among the various units; where examples of the CAN message data frame format, serial communication frame format, and fault isolation truth table are referred to Figures 5 - 7 ;

[0069] Power on the device, output valid control signals for all indicator lights, and the ADC and sensor acquisition circuits start working;

[0070] Receive the message sent through the CAN bus from the drive control unit, extract the ID and valid data content of the message. Obtain the sensor acquisition results in real time and poll each acquisition channel to obtain the ADC sampling value, and compare the ADC sampling result with the preset threshold range;

[0071] Power-on self-check process;

[0072] Periodic self-check process;

[0073] End the self-check process.

[0074] Among them, the steps of the power-on self-check process include:

[0075] Filter and screen the messages according to the message ID. For the bus where the power drive unit is located in the control area, if a message sent by any drive unit on the bus is retrieved, it is considered that the power-on self-check of the bus communication is normal; otherwise, the power-on self-check result will remain in the non-passing state;

[0076] The power-on self-check results of the bus where the power drive unit is located in the control area and the voltage or current sampled by the ADC will be used as the CAN message data content, combined with the message ID for the current sub-control unit to report self-check information allocated by the communication protocol, and the message will be sent to the CAN interface.

[0077] When the voltage or circuit sampling result exceeds the threshold, counting starts, and the count is cleared when it returns within the threshold range; when the count exceeds t0, the power-on self-check of this voltage or circuit fails.

[0078] The power-on self-check process ends, with a duration of t1, where t1 > 10 * t0.

[0079] Among them, the steps of the periodic self-check process include:

[0080] When it is detected that the external "test" signal is not activated, the periodic self-check process is entered.

[0081] Judge whether the voltage or circuit sampling result exceeds the threshold; if it exceeds, counting starts, and the count is cleared when it returns within the threshold range. When the count exceeds t0, it is considered that the periodic self-check of this voltage or circuit fails, and the failed state is continuously maintained until it returns to the normal threshold range and lasts for a duration of t1.

[0082] Set the time interval for the power drive unit to send CAN messages to the sub-control unit as t2, and perform message filtering and screening according to the message ID.

[0083] For the bus where the power drive unit is located within the control area, if no message reported by any power drive unit on a bus is received within 10 * t2 time, then this bus enters the fault state and the periodic self-check fails; if 10 valid messages sent by power drive units are received within 20 * t2 in the fault state, then the bus returns to normal.

[0084] For the power drive unit within the control area, if no message reported by this unit is received within 10 * t2 time, then it is considered that this power drive unit enters the fault state and the periodic self-check fails; if 10 valid messages sent by this power drive unit are received within 20 * t2 in the fault state, then it is considered that this power drive unit returns to normal and the periodic self-check passes.

[0085] Integrate the real-time acquisition results of the comprehensive sensor, voltage or current, and the periodic self-check results of the CAN bus and the power drive unit, and judge the fault nodes and fault states within the control area according to the fault truth table, and send fault information to the main control unit at time interval t2.

[0086] The power drive unit sends CAN messages to the sub-control unit, performs message filtering and screening according to the message ID, and judges the fault states of the bus where the power drive unit is located within the control area and the power drive unit within the control area.

[0087] Debounce the "test" control signal; if the control signal input continues to be maintained, enter the next step, otherwise return to the periodic self-check process.

[0088] Terminate the input signal detection for controls other than "Emergency Braking" and "Test", force the drive control circuit to start running for time t3, update the real-time fault status of voltage or current at the time point of t3 / 2, and maintain this status until the end of time t3;

[0089] Comprehensively collect the real-time acquisition results of sensors, voltage or current, and the periodic self-check results of the CAN bus and the power drive unit, and judge the fault nodes and fault status in the control area according to the fault truth table

[0090] Detect again whether the "Test" control signal is valid. If it is invalid, return to the periodic self-check. If it is valid, keep the current fault diagnosis result and send it to the main control unit;

[0091] End the self-check process.

[0092] Embodiment 2

[0093] A cargo aircraft cargo loading fault isolation control system based on the CAN bus, referring to Figures 1 - 4 , the cargo aircraft cargo loading system based on the CAN bus includes a main control unit, a sub-control unit, a drive control circuit, and a power drive unit; the main control unit, which is a combination of a control computer and a main human-computer interaction interface, is connected to each sub-control unit through the CAN bus, sends instructions to the sub-control unit, receives feedback information from the sub-control unit, and displays the equipment operation status and fault information;

[0094] The sub-control unit is used to provide control signals to the drive control circuit, is connected to the main control unit and the power drive unit through the CAN bus, receives the status information sent by the power drive unit and sends the comprehensively processed information to the main control unit;

[0095] The drive control circuit is used to receive the control signals from the sub-control unit and convert them into corresponding control actions;

[0096] The power drive unit, as the physical carrier of the controlled node, is controlled by the drive control circuit and is connected to the sub-control unit through the CAN bus.

[0097] The sub-control unit is used to implement the fault isolation control method. The sub-control unit includes a control panel and an FPGA control circuit;

[0098] The control panel, a human-computer interaction panel, the digital signal output of the controls on the panel is connected to the discrete instruction module, receives the electrical signals output by the status indication control module and converts them into optical signals. The control panel has "Emergency Braking", "Test" and other controls for controlling the movement of the power drive unit, has control enable indicators for the controls, and has indicators for some statuses in the control area.

[0099] The FPGA control circuit includes a discrete instruction recognition module, a status indication control module, a sensor acquisition module, an instruction processing module, a data processing module, an ADC acquisition module, a voltage and current detection module, a fault detection and isolation module, a serial communication module, a configuration module, a communication self-check module, and a CAN interface module; as an alternative embodiment, the FPGA is implemented using an FPGA from Xilinx, with the model number xc7a100tfgg484-3.

[0100] The discrete instruction recognition module has its input interface connected to an external digital control, and outputs control signals to the instruction processing module and the status indication control module; it acquires the digital signals input by the control panel control, performs debounce processing, and the signal is stably maintained for 5 ms or more under specified state conditions, then outputs digital control signals to the instruction processing module and the status indication control module, otherwise ignores the signal input.

[0101] The status indication control module has its input interfaces connected to the discrete instruction recognition module and the instruction processing module, and its output interface connected to the light-emitting part of the control panel; it combines the digital control signals output from the discrete instruction processing module and the status signals of the instruction processing module and converts them into corresponding levels for output, to achieve the control of the light-emitting devices on the control panel.

[0102] The sensor acquisition module outputs the sensor acquisition results to be connected to the instruction acquisition module; it converts the optical signal into an electrical signal and transmits the acquisition results to the instruction processing module. The sensor acquisition results will be used as one of the reference bases for the normal operation of the power drive unit.

[0103] The instruction processing module has its input interfaces connected to the sensor acquisition module, the discrete instruction recognition module, the fault detection and isolation module, and the data processing module, and its output interfaces connected to the status indication control module, the fault detection and isolation module, and the data processing module; it receives the sensor acquisition results of the sensor acquisition module, the control signals of the discrete instruction recognition module, the fault diagnosis results and self-check results of the fault detection and isolation module, combines the overall control information of the main control unit transmitted through the CAN bus and the status information of the power drive unit, selects the final drive control signal and summarizes various status information, and uses the form of a state machine to implement the parsing of the structure body and the encapsulation and sending of the sending direction structure body.

[0104] In the initial state of receiving and parsing, an RDY signal is provided to the data processing module to notify it that this module is idle and can perform structure parsing. After receiving the structure transmitted by the data processing module, it enters the busy state and the RDY signal is pulled low. According to the ID and DLC in the structure, the valid byte data in the DATA is obtained, and the meaning of the data is confirmed according to the communication protocol. After parsing a structure, it will return to the initial state of receiving and parsing. Through information interaction with different modules, the obtained status information will be transmitted to the status instruction control module and the fault detection and isolation module, and the obtained drive control information will be combined with the control area status for the drive control circuit.

[0105] Upon detecting the power-on self-check completion indication output by the fault detection and isolation module, the transmission process is enabled. As an optional embodiment, the system clock period is 10 ns, the number of structures to be transmitted in one round is within 100, and the time interval between each round of transmissions is 40 ms. A 40 ms timer and a counter cnt_tx_cmd are constructed to control the message transmission, with an initial value of 0. When the rising edge of the power-on self-check completion signal is detected or the timer counts up to 40 ms, cnt_tx_cmd is set to 1 in the next clock cycle and accumulates according to the clock cycle until it counts up to the maximum number of structures to be transmitted required, and then is set to 0 in the next clock cycle until it counts up to 40 ms again. Each value of cnt_tx_cmd greater than 0 corresponds to a message ID, and different data contents will be transmitted according to the communication protocol based on different message IDs.

[0106] The data processing module has its input interface connected to the CAN interface module and the instruction processing module, and its output interface connected to the CAN processing module and the instruction processing module; for each CAN interface module, two FIFOs with a bit width of 99 bits and a depth of 1024 are instantiated, serving as the receive buffer (RX) and the transmit buffer (TX) respectively. Receive the structures from each CAN interface module, parse out the message identifier (ID), and determine whether the ID is the message ID expected to exist on the CAN bus connected to the CAN interface module. If so, store the structure in the RX_FIFO corresponding to the CAN interface module; otherwise, discard the structure. When any one of the RX_FIFOs is non-empty and the RDY signal of the instruction processing module is 1, the structure in the RX_FIFO can be read out to the instruction processing module; when multiple RX_FIFOs are non-empty simultaneously, the structure in the RX_FIFO with a lower subscript is preferentially read out. Generally, the RX_FIFO with a lower subscript matches the structure with a higher ID processing priority. In this embodiment, the CAN bus connecting the main control unit and the sub-control unit has the highest priority; only the structure in one RX_FIFO will be read out to the instruction processing module at the same time. Receive the structure transmitted from the instruction processing module, and distribute it to the TX_FIFO corresponding to each corresponding CAN interface module according to the ID in the structure. Check whether the TX_FIFO is non-empty every 1 ms. If it is non-empty, read out a structure and transmit it to the CAN interface module. Multiple TX_FIFOs can read out structures at the same time.

[0107] The ADC acquisition module acquires analog signals and outputs them as digital signals to the voltage and current monitoring module; as an alternative embodiment, the ADC128S chip is used to implement the acquisition and analog-to-digital conversion functions of partial voltage or current within the control area, poll each acquisition channel, and output the sampled values of voltage or current to the voltage and current monitoring module.

[0108] The voltage and current monitoring module receives the digital signals from the ADC acquisition module, receives the threshold information from the configuration module, and outputs the monitoring results to the fault monitoring and isolation module; compares the sampled values of voltage or current from the ADC acquisition module with the voltage or current threshold ranges from the configuration module in real time. During the power-on self-check, if the sampled value of voltage or current exceeds the specified threshold range and lasts for 200 ms, it is considered that the power-on self-check of the voltage or current fails. After the power-on self-check is completed, it enters the periodic self-check stage. If the sampled value of voltage or current exceeds the specified threshold range and lasts for 200 ms, it is considered that the periodic self-check of the voltage or current fails, and the periodic self-check result is a fault; when it returns to the normal threshold range and lasts for 200 ms, it is considered that the voltage or current is working normally. The results of the current or voltage self-check will be output to the fault monitoring and isolation module and used as one of the bases for fault diagnosis in the fault isolation module.

[0109] A fault detection and isolation module, whose input interface is connected to the communication self-check module and the instruction processing module, outputs the results of fault detection to the instruction processing module; receives the power-on self-check completion indication from the communication self-check module, integrates the power-on self-check results of voltage, current and CAN bus and transmits them transparently to the instruction processing module, and then starts periodic fault diagnosis.

[0110] Refer to Figure 7 , the diagnosis basis is the fault isolation truth table, "√" indicates that the self-check result is normal, "×" indicates that the self-check result is abnormal, and a fault diagnosis is performed every 400 ms and the fault information output to the instruction processing module is updated. When receiving a valid "test" control signal transmitted from the instruction processing module, a test process enable indication will be generated and fed back to the instruction processing module, and it will mask the control signals except the "test" and "emergency brake" controls. When the test process starts, all power drive units in the forced drive control area will be forced to operate in the normal working state for 3 s. Considering the time difference between the generation of the drive control signal and the response behavior of the power drive unit, the fault diagnosis is carried out only after 1.5 s. When the operation time ends, the obtained fault diagnosis result will no longer change until the "test" control indication fails, and then the fault diagnosis is carried out according to the real-time self-check result.

[0111] A serial communication module converts serial data into parallel data and outputs it to the configuration module, converts the parallel data from the configuration module into serial data and outputs it to the outside; communicates with the outside through RS422 / UART. The baud rate of serial data transmission is 115200. Each byte of data is serially received or sent in the form of 1 bit low-level start bit, 8 bits of data, and 1 bit high-level end bit. The data position where the lower bit is sent or received first within the byte is located at the lower bit within the byte.

[0112] Refer to Figure 6 , one count is increased for each valid byte received in the receiving direction. When the count reaches 11 bytes, it is judged whether it is a valid data frame. If not, the first received byte data is excluded, and the second received byte data becomes the earliest received byte data currently, and so on, until it is detected that the first byte and the last byte within these 11 bytes match the frame header and frame tail characters of the frame format, then the count is cleared, and at the same time, the ID information, operation type, operation address and operation data content are extracted. If the ID meets the expectation and the operation type is a valid value, the operation type, operation address and operation data content are transmitted to the configuration module. When receiving the read operation response indication from the configuration module, the return value of the configuration module is encapsulated according to the frame format and converted into serial data and sent out.

[0113] The configuration module has its input interface connected to the serial communication module and outputs configuration information to the voltage and current monitoring module and the communication self-check module. It is used to store the control circuit parameter settings. For example, voltage or circuit threshold parameters are used by the voltage and current detection module. When receiving the operation instruction from the serial communication module, if it is a write operation, it writes the operation data content into the register corresponding to the operation address; if it is a read operation, it obtains the value of the register corresponding to the operation address and returns it to the serial communication module.

[0114] The communication self-check module has its input interface connected to the CAN interface module and the configuration module, and its output interface connected to the fault detection and isolation module. It receives the structure transmitted by the CAN interface module, extracts the message ID. During the power-on self-check time, for the bus where the power drive unit is located, if a message sent by any drive unit is retrieved, it is considered that the bus communication is normal. After the power-on self-check ends, it transmits the power-on self-check result to the fault detection and isolation module. After the power-on self-check ends, it enters the periodic self-check. When no message reported by any power drive unit on a bus is received within 400 ms, it is considered that the bus enters the fault state, and the periodic self-check result output to the fault detection and isolation module is set to 1. When ten valid messages are reported by the bus within 800 ms in the fault state, it is considered that the bus communication resumes normal, and the output periodic self-check result is set to 0. For the power drive unit within the control area, when no message reported by the unit is received within 400 ms, it is considered that the power drive unit enters the fault state and the periodic self-check fails; when 10 valid messages sent by the power drive unit are received by the bus within 800 ms in the fault state, it is considered that the power drive unit resumes normal and the periodic self-check passes. The time values of 400 ms and 800 ms are provided by the configuration module.

[0115] The CAN interface module has its input and output interfaces connected to the CAN bus network, has two-way data interaction with the data processing module, and outputs messages to the communication self-check module. It implements the CAN interface underlying protocol.

[0116] Refer to Figure 5 , and use the extended frame format in the protocol data frame format. It receives CAN messages from the main control unit and the power drive unit, converts them into the structure form and outputs them to the data processing module and the communication self-check module. It also receives the structure data encapsulated by the data processing module and sends it to the CAN bus. Each pair of CAN_H and CAN_L bus signals will use one CAN interface module.

[0117] In the embodiments of the present application, the implementation principle of a cargo aircraft cargo loading fault isolation control method based on the CAN bus is as follows: Multiple sets of devices share the same main control unit. The main control unit integrates the information fed back by each sub-control unit as the overall control and has the highest CAN message transmission priority. Each sub-control unit in each embodiment has an independent control area. The power drive units within the control area feed back their own status information to the sub-control unit, and the sub-control unit realizes the control of all power drive units within this area through the drive control circuit. The main control unit can indirectly control the power drive units by sending control messages to the sub-control units.

[0118] It should be understood that for those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A cargo plane cargo loading fault isolation control method based on CAN bus, characterized in that: include When it is detected that the external "test" signal is not activated, it enters the periodic self-test process; Determine whether the voltage or circuit sampling result exceeds the preset safety threshold; Receive messages sent by the power drive unit through the CAN bus, filter and screen the messages according to the message ID, and determine the bus where the power drive unit in the control area is located and the fault status of the power drive unit in the control area; De-jitter the "test" control signal; Secondary verification of the validity of the "test" signal. If it is invalid, it will return to the periodic self-test. If it is valid, it will keep the current fault diagnosis result and send it to the main control unit; End the self-check process.

2. The method for isolating and controlling cargo loading faults of a cargo plane based on a CAN bus according to claim 1, characterized in that: The step of receiving a message sent by a power drive unit through a CAN bus, filtering and screening the message according to a message ID, and determining the bus where the power drive unit in the control area is located and the fault state of the power drive unit in the control area includes: Assign the CAN message IDs to the main control unit, sub-control unit and power drive unit; confirm the cross-linking information, CAN message communication protocol and fault isolation truth table between each unit; The device is powered on, outputs valid control signals for all indicators, and starts the ADC and sensor acquisition circuits; Receive messages sent from the drive control unit through the CAN bus, extract the message ID and valid data content; obtain sensor acquisition results in real time and poll each acquisition channel to obtain ADC sampling values, and compare the ADC sampling results with the preset threshold range; Set the time interval for the power drive unit to send CAN messages to the sub-control unit to t2, and filter and select the messages according to the message ID; For the bus where the power drive units in the control area are located, if no message reported by any power drive unit on the bus is received within 10*t2, the bus enters a fault state and fails the periodic self-test; when there are valid messages sent by 10 power drive units on the bus within 20*t2 in the fault state, the bus returns to normal.

3. The method for isolating and controlling cargo loading faults of a cargo plane based on a CAN bus according to claim 2, characterized in that: Based on the failure to detect the "test" signal, the steps to enter the periodic self-test process are: For the power drive unit in the control area, when no message reported by the unit is received within 10*t2, it is considered that the power drive unit has entered a fault state and the periodic self-test has failed; when there are 10 valid messages sent by the power drive unit within 20*t2 of the bus in the fault state, it is considered that the power drive unit has returned to normal and the periodic self-test has passed.

4. The method for isolating and controlling cargo loading faults of a cargo plane based on a CAN bus according to claim 1, characterized in that: It also includes the power-on self-test process; The steps based on the power-on self-test process include: Filter and screen messages according to message IDs. For the bus where the power drive unit in the control area is located, if a message sent by any drive unit on the bus is retrieved, it is considered that the bus communication power-on self-test is normal, otherwise the power-on self-test result will remain in a failed state; The power-on self-test results of the bus where the power drive unit in the control area is located and the voltage or current sampled by the ADC will be used as the CAN message data content, combined with the message ID of the current sub-control unit reporting the self-test information assigned in the communication protocol, and the message will be sent to the CAN interface.

5. A method for isolating and controlling cargo loading faults of a cargo plane based on a CAN bus according to claim 4, characterized in that: The steps for performing a power-on self-test include: When the voltage or circuit sampling result exceeds the threshold, counting begins, and the count is reset when it returns to the threshold range; when the count exceeds t0, the voltage or circuit power-on self-test fails; The power-on self-test process ends, and the duration is t1, where t1>10*t0.

6. The method for isolating and controlling cargo loading faults of a cargo plane based on a CAN bus according to claim 1, characterized in that: The steps based on de-jittering the "test" control signal include: The control signal input state is maintained continuously; Stop the input signal detection of controls other than "emergency brake" and "test", force the drive control circuit to start running for t3 time, and update the real-time fault status of voltage or current at the time point of t3 / 2, and keep this status until the end of t3 time; The real-time collection results of the comprehensive sensor, the voltage or current, and the periodic self-test results of the CAN bus and the power drive unit are used to determine the fault node and fault status in the control area according to the fault truth table.

7. The method for isolating and controlling cargo loading faults of a cargo plane based on a CAN bus according to claim 1, characterized in that: The step of judging whether the voltage or circuit sampling result exceeds the threshold comprises: If it exceeds, it starts counting. If it returns to the threshold range, the count is reset. When the count exceeds t0, it is considered that the voltage or circuit cycle self-test has failed, and it will continue to fail until it returns to the normal threshold range and lasts for t1; The real-time collection results of the comprehensive sensor, the voltage or current, and the periodic self-test results of the CAN bus and the power drive unit are used to determine the fault nodes and fault states in the control area according to the fault truth table, and the fault information is sent to the main control unit at the time interval t2.

8. A cargo plane cargo loading fault isolation control system based on CAN bus, comprising a main control unit, a sub-control unit and a power drive unit; characterized in that: The sub-control unit is used to provide control signals to the drive control circuit, is connected to the main control unit and the power drive unit through the CAN bus, receives status information sent by the power drive unit and sends the comprehensively processed information to the main control unit; The sub-control unit includes a control panel and an FPGA control circuit; Control panel, human-machine interaction panel, the digital signal output of the control on the panel is connected to the discrete instruction module, receives the electrical signal output from the status indication control module and converts it into an optical signal.

9. A cargo plane cargo loading fault isolation control system based on CAN bus according to claim 8, characterized in that: The FPGA control circuit includes a discrete instruction recognition module, a status indication control module, a sensor acquisition module, an instruction processing module, a data processing module, an ADC acquisition module, a voltage and current detection module, a fault detection and isolation module, a serial port communication module, a configuration module, a communication self-test module and a CAN interface module; A discrete instruction recognition module, whose input interface is connected to an external digital control, outputs control signals to the instruction processing module and the status indication control module; A status indication control module, the input interface of which is connected to the discrete instruction recognition module and the instruction processing module, and the output interface of which is connected to the light-emitting part of the control panel; The sensor acquisition module outputs the sensor acquisition results to the instruction acquisition module; The command processing module has an input interface connected to the sensor acquisition module, the discrete command recognition module, the fault detection and isolation module, and the data processing module, and an output interface connected to the status indication control module, the fault detection and isolation module, and the data processing module; The data processing module has an input interface connected to the CAN interface module and the instruction processing module, and an output interface connected to the CAN processing module and the instruction processing module; ADC acquisition module collects analog signals, converts them into digital signals and outputs them to the voltage and current monitoring module; The voltage and current monitoring module receives the digital signal from the ADC acquisition module, receives the threshold information from the configuration module, and outputs the monitoring results to the fault monitoring and isolation module; The fault detection and isolation module has an input interface connected to the communication self-check module and the instruction processing module, and outputs the fault detection result to the instruction processing module; The serial communication module converts serial data into parallel data and outputs it to the configuration module, and converts parallel data from the configuration module into serial data and outputs it to the outside world; Configuration module, the input interface is connected to the serial communication module, and outputs configuration information to the voltage and current monitoring module and the communication self-test module; Communication self-check module, the input interface is connected with the CAN interface module and the configuration module, and the output interface is connected with the fault detection and isolation module; The CAN interface module, whose input and output interfaces are connected to the CAN bus network, has two-way data interaction with the data processing module, and outputs messages to the communication self-test module.

10. A cargo plane cargo loading fault isolation control system based on CAN bus according to claim 8, characterized in that: The cargo plane cargo loading system also includes a drive control circuit; the main control unit is a collection of a control computer and a main human interface, which is connected to each sub-control unit through a CAN bus, sends instructions to the sub-control unit, receives feedback information from the sub-control unit, and displays the equipment operation status and fault information; The driving control circuit is used to receive the control signal from the sub-control unit and convert it into a corresponding control behavior; The power drive unit, as the physical carrier of the controlled node, is controlled by the drive control circuit and connected to the sub-control unit through the CAN bus.

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