Multi-channel acquisition circuit, method and airborne device for use in an airborne system

Abstract

The application provides a multi-channel acquisition circuit and method applied to an airborne system and an airborne device, and relates to the technical field of avionics circuits. A controller determines a target sensor sampling channel according to a preset sampling time slice and generates an excitation gear switching instruction according to the target sensor sampling channel, and sends the excitation gear switching instruction to a multi-range constant-current excitation source module to make the multi-range constant-current excitation source module switch to a target constant-current gear. The controller generates a path switching instruction according to the preset sampling time slice, and sends the path switching instruction to a first analog multiplexer to make the first analog multiplexer switch to a reference resistance array or a sensor array. A sampling module is used for collecting a first sampling voltage value of the sensor array and a second sampling voltage value of the reference resistance array, and transmitting the first sampling voltage value and the second sampling voltage value to the controller. The controller compensates the first sampling voltage value by using a voltage compensation parameter determined according to the second sampling voltage value under the target constant-current gear. The consistency between a BIT detection result and a real measurement link state can be improved, and the self-checking coverage capability can be improved.

Description

Technical Field

[0001] This application relates to the field of avionics circuit technology, and in particular to a multi-channel acquisition circuit, method, and airborne equipment for use in airborne systems. Background Technology

[0002] Airborne sensor acquisition systems play a crucial role in modern aircraft platforms such as highly integrated electromechanical control systems, electric propulsion aircraft, unmanned aerial vehicles (UAVs), and electric vertical take-off and landing (eVTOL) aircraft. These systems place stringent requirements on the security, stability, and measurement accuracy of sensor acquisition interfaces to ensure the reliability of flight control and condition monitoring.

[0003] In the prior art, sensor acquisition circuits used in airborne systems typically have a built-in self-test (BIT) mechanism, which is designed to enable self-checking of the integrity of hardware functions.

[0004] However, some existing built-in self-test BIT excitation points are usually located in the analog-to-digital conversion or digital processing stage, or use a calibration branch that is independent of normal measurement, making it difficult to verify the full-link error from the excitation path to the sampling path. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of the prior art by providing a multi-channel acquisition circuit, method, and airborne equipment for use in airborne systems, which can improve self-test coverage capability.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, this application provides a multi-channel acquisition circuit for an airborne system, comprising: a first analog multiplexer, a multi-range constant current excitation source module, a sensor array, a reference resistor array, a sampling module, and a controller; The control terminal of the first analog multiplexer and the input terminal of the multi-range constant current excitation source module are electrically connected to the first output terminal and the second output terminal of the controller, respectively. The first analog multiplexer includes a common terminal and multiple selectable channels. The common terminal is electrically connected to the output terminal of the multi-range constant current excitation source module. At least one of the multiple selectable channels is electrically connected to the input terminal of the sensor array, and the remaining multiple selectable channels are electrically connected to the input terminal of the reference resistor array, respectively. The first sampling terminal of the sampling module is electrically connected to the input terminal of the reference resistor array and the input terminal of the sensor array, respectively. The second sampling terminal of the sampling module is electrically connected to the first output terminal of the reference resistor array and the output terminal of the sensor array, respectively. The output terminal of the sampling module is electrically connected to the input terminal of the controller. The controller is configured to generate a path switching instruction based on a preset sampling time slice and send it to the first analog multiplexer, determine the target sensor sampling channel based on the preset sampling time slice, and generate an excitation level switching instruction based on the target sensor sampling channel and send it to the multi-range constant current excitation source module. The multi-range constant current excitation source module is used to switch to the target constant current level corresponding to the target sensor sampling channel according to the excitation level switching command; The first analog multiplexer is used to switch to an electrical connection with the input terminal of the reference resistor array or the input terminal of the sensor array according to the path switching command; the second output terminal of the reference resistor array is connected to the analog reference terminal, and when the first analog multiplexer switches to the reference resistor array, a closed current loop of the BIT path is formed. The sampling module is used to acquire a first sampled voltage value of the sensor array and transmit it to the controller when the first analog multiplexer is electrically connected to the input terminal of the sensor array; and to acquire a second sampled voltage value of the reference resistor array and transmit it to the controller when the first analog multiplexer is electrically connected to the input terminal of the reference resistor array, so that the controller can compensate the first sampled voltage value using a voltage compensation parameter determined according to the second sampled voltage value at the target constant current level.

[0007] In an optional embodiment, the sensor array includes: a plurality of resistive sensors, and the multi-channel acquisition circuit further includes: a second analog multiplexer, the control terminal of the second analog multiplexer being electrically connected to the third output terminal of the controller, the multiple independent channel output terminals of the second analog multiplexer being electrically connected to one end of each of the plurality of resistive sensors in the sensor array, and the common terminal of the second analog multiplexer being connected to an analog reference terminal; The controller is also configured to generate a channel switching instruction based on a preset sampling time slice and send it to the second analog multiplexer; The second analog multiplexer is used to control the sensor array to switch to the target sensor sampling channel according to the channel switching command.

[0008] In an optional implementation, the controller is specifically configured to generate a first path switching instruction based on a preset sampling time slice and send it to the first analog multiplexer, or to determine a sampling idle time slice based on the preset sampling time slice, generate a periodic BIT self-test instruction based on the sampling idle time slice, and generate a second path switching instruction based on the periodic BIT self-test instruction and send it to the first analog multiplexer. The first analog multiplexer is configured to switch to electrical connection with the input terminal of the sensor array during the preset sampling time slice according to the first path switching instruction, or to switch to electrical connection with the input terminal of the reference resistor array during the sampling idle time slice according to the second path switching instruction to perform periodic BIT detection.

[0009] In an optional implementation, the controller is further configured to acquire a fault self-test command or a power-on self-test command, generate a second path switching command based on the fault self-test command or the power-on self-test command, and send it to the first analog multiplexer. The first analog multiplexer is configured to switch to an electrical connection with the input of the reference resistor array according to the second path switching instruction to perform fault BIT detection or power-on BIT detection.

[0010] In an optional implementation, the controller compensates the first sampled voltage value at the target constant current level using voltage compensation parameters determined based on the second sampled voltage value, including: The controller calculates voltage compensation parameters based on the second sampled voltage value and the theoretical reference voltage corresponding to the target constant current level; The first sampled voltage value is compensated according to the voltage compensation parameters, and the compensated first sampled voltage value is output.

[0011] In an optional implementation, the controller is further configured to determine the resistance value of the target resistive sensor corresponding to the target sensor sampling channel based on the compensated first sampling voltage value and the calibration excitation current corresponding to the target constant current level.

[0012] In an optional implementation, the controller is further configured to calculate the normalized link deviation based on the second sampled voltage value and the theoretical reference voltage corresponding to the target constant current level. The health status of the acquisition link is assessed based on the normalized link deviation.

[0013] In an optional implementation, the controller is further configured to determine whether the first sampled voltage value is less than the preset linear lower limit threshold corresponding to the sampling module based on the voltage outer loop algorithm; if so, a shift request is generated. Determine whether the first sampled voltage value is greater than the preset linear upper limit threshold corresponding to the sampling module. If so, generate a downshifting request. After the controller determines that the upshift or downshift request is allowed based on the stability inner loop algorithm, it sends an upshift or downshift command to the multi-range constant current excitation source module.

[0014] In an optional implementation, the controller is further configured to, after generating the upshift request, obtain a first sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm; or, after generating the downshift request, obtain a second sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm. A shift-up instruction is generated based on the first sampling sequence and sent to the multi-range constant current excitation source module; or a shift-down instruction is generated based on the second sampling sequence and sent to the multi-range constant current excitation source module.

[0015] In an optional implementation, the controller is specifically configured to calculate a first variance value based on the first sampling sequence, or to calculate a second variance value based on the second sampling sequence; If the first variance value is determined to be less than the first variance threshold, an upshift switching command is generated and sent to the multi-range constant current excitation source module; if the first variance value is greater than or equal to the first variance threshold, the current constant current level is maintained; if the second variance value is determined to be less than the second variance threshold, an downshift switching command is generated and sent to the multi-range constant current excitation source module; if the second variance value is greater than or equal to the second variance threshold, the current constant current level is maintained.

[0016] In an optional implementation, the sampling module includes: a differential sampling circuit and an analog-to-digital conversion module; The sampling terminals of the reference resistor array and the sensor array are electrically connected to the input terminal of the differential sampling circuit, respectively. The output terminal of the differential sampling circuit is electrically connected to the input terminal of the analog-to-digital converter module, and the output terminal of the analog-to-digital converter module is electrically connected to the input terminal of the controller. The differential sampling circuit and the second analog multiplexer form a single-channel conditioning multiplexing structure for polling and acquiring the quasi-static resistance signal output by the resistive temperature sensor in the sensor array.

[0017] In an optional implementation, the reference resistor array includes at least three reference resistors, which at least indicate: a low-resistance reference resistor, a medium-resistance reference resistor, and a high-resistance reference resistor, for use as a known test object during BIT testing; The multi-range constant current excitation source module includes multiple controlled constant current output branches, each of which is equipped with an independent precision feedback resistor to output the corresponding constant current range.

[0018] In an optional embodiment, the sensor array includes at least one of the following: NTC thermistor, PTC thermistor, and platinum resistance thermometer.

[0019] Secondly, this application provides a multi-channel acquisition method for an airborne system, applied to a controller in a multi-channel acquisition circuit for an airborne system as described in any of the foregoing embodiments, the method comprising: A path switching command is generated based on a preset sampling time slice and sent to the first analog multiplexer. The target sensor sampling channel is determined based on the preset sampling time slice. An excitation level switching command is generated based on the target sensor sampling channel and sent to the multi-range constant current excitation source module. The multi-range constant current excitation source module switches to the target constant current level corresponding to the target sensor sampling channel based on the excitation level switching command. The first analog multiplexer is used to switch to an electrical connection with the input terminal of the reference resistor array or the input terminal of the sensor array based on the path switching command. When the first analog multiplexer is electrically connected to the input terminal of the sensor array, the sampling module obtains the first sampled voltage value of the sensor array; when the first analog multiplexer is electrically connected to the input terminal of the reference resistor array, the sampling module obtains the second sampled voltage value of the reference resistor array. At the target constant current level, the first sampled voltage value is compensated using voltage compensation parameters determined based on the second sampled voltage value.

[0020] In an optional implementation, the controller is further configured to determine whether the first sampled voltage value is less than the preset linear lower limit threshold corresponding to the sampling module based on the voltage outer loop algorithm; if so, a shift request is generated. Determine whether the first sampled voltage value is greater than the preset linear upper limit threshold corresponding to the sampling module. If so, generate a downshifting request. After the controller determines that the upshift or downshift request is allowed based on the stability inner loop algorithm, it sends an upshift or downshift command to the multi-range constant current excitation source module.

[0021] In an optional implementation, the controller is further configured to, after generating the upshift request, obtain a first sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm; or, after generating the downshift request, obtain a second sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm. A shift-up instruction is generated based on the first sampling sequence and sent to the multi-range constant current excitation source module; or a shift-down instruction is generated based on the second sampling sequence and sent to the multi-range constant current excitation source module.

[0022] In an optional implementation, the controller is specifically configured to calculate a first variance value based on the first sampling sequence, or to calculate a second variance value based on the second sampling sequence; If the first variance value is determined to be less than the first variance threshold, an upshift switching command is generated and sent to the multi-range constant current excitation source module; if the first variance value is greater than or equal to the first variance threshold, the current constant current level is maintained; if the second variance value is determined to be less than the second variance threshold, an downshift switching command is generated and sent to the multi-range constant current excitation source module; if the second variance value is greater than or equal to the second variance threshold, the current constant current level is maintained.

[0023] Thirdly, this application provides an airborne device, including a multi-channel acquisition circuit applied to an airborne system as described in any of the foregoing embodiments.

[0024] The beneficial effects of this application are: The multi-channel acquisition circuit, method, and airborne equipment provided in this application, applicable to airborne systems, include: a first analog multiplexer, a multi-range constant current excitation source module, a sensor array, a reference resistor array, a sampling module, and a controller. The controller is configured to generate a path switching instruction based on a preset sampling time slice and send it to the first analog multiplexer; determine the target sensor sampling channel based on the preset sampling time slice; and generate an excitation level switching instruction based on the target sensor sampling channel and send it to the multi-range constant current excitation source module. The multi-range constant current excitation source module is configured to switch to the target constant current level corresponding to the target sensor sampling channel based on the excitation level switching instruction. The first analog multiplexer is configured to switch to the target constant current level corresponding to the target sensor sampling channel based on the path switching instruction. The input terminal of the reference resistor array, or, is electrically connected to the input terminal of the sensor array; the sampling module is used to acquire the first sampled voltage value of the sensor array and transmit it to the controller when the first analog multiplexer is electrically connected to the input terminal of the sensor array; and to acquire the second sampled voltage value of the reference resistor array and transmit it to the controller when the first analog multiplexer is electrically connected to the input terminal of the reference resistor array, so that the controller compensates the first sampled voltage value with voltage compensation parameters determined according to the second sampled voltage value at the target constant current level. Compared with setting an independent calibration branch, it can realize the unification of measurement function and detection function, improve the consistency between BIT detection results and the actual measurement link status, and improve self-test coverage capability.

[0025] Furthermore, this application connects multiple resistive sensors to the same differential sampling circuit and analog-to-digital conversion module in a time-division manner through a second analog multiplexer, eliminating the need to set up a conditioning circuit for each sensor channel, thereby reducing the number of conditioning devices and board space occupied, and reducing the workload of inter-channel consistency calibration; the differential sampling circuit acquires the voltage across the selected resistive sensor, which can also reduce the influence of the on-resistance of the second analog multiplexer and its temperature drift on the measurement results. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A functional module diagram of a multi-channel acquisition circuit applied to an airborne system is provided in an embodiment of this application; Figure 2 A schematic diagram of another functional module of a multi-channel acquisition circuit applied to an airborne system, provided in an embodiment of this application; Figure 3 A flowchart illustrating a multi-channel data acquisition method for an airborne system, provided as an embodiment of this application; Figure 4 A flowchart illustrating another multi-channel acquisition method for airborne systems provided in this application embodiment; Figure 5 A flowchart illustrating another multi-channel acquisition method for airborne systems provided in this application embodiment; Figure 6 This is a flowchart illustrating another multi-channel acquisition method for airborne systems provided in an embodiment of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] Figure 1 This is a functional module diagram of a multi-channel acquisition circuit applied to an airborne system, provided as an embodiment of this application. The airborne system in this application can specifically be an electric vertical takeoff and landing (eVTOL) aircraft system, an electric propulsion unmanned aerial vehicle (UAV) system, etc., and is not limited thereto. Figure 1 As shown, the multi-channel acquisition circuit may include: a first analog multiplexer 101, a multi-range constant current excitation source module 102, a sensor array 103, a reference resistor array 104, a sampling module 105, and a controller 106.

[0032] Optionally, the controller 106 may be implemented using a microcontroller, a processor, a programmable logic device, or a combination thereof. For example, for scenarios requiring deterministic timing control, a programmable logic device may be selected as the controller 106. This is not limited here, and the choice can be made flexibly according to the actual application scenario.

[0033] The control terminal of the first analog multiplexer 101 and the input terminal of the multi-range constant current excitation source module 102 are electrically connected to the first output terminal and the second output terminal of the controller 106, respectively. The first analog multiplexer 101 includes a common terminal and multiple selectable channels. The common terminal is electrically connected to the output terminal of the multi-range constant current excitation source module 102. At least one of the multiple selectable channels is electrically connected to the input terminal of the sensor array 103, and the remaining multiple selectable channels are electrically connected to the input terminal of the reference resistor array 104, respectively.

[0034] The output terminal of the multi-range constant current excitation source module 102 is electrically connected to the input terminal of the first analog multiplexer 101, and the output terminal of the first analog multiplexer 101 is electrically connected to the input terminal of the reference resistor array 104 or the input terminal of the sensor array 103.

[0035] The first sampling terminal of the sampling module 105 is electrically connected to the input terminal of the reference resistor array 104 and the input terminal of the sensor array 103, respectively. The second sampling terminal of the sampling module 105 is electrically connected to the first output terminal of the reference resistor array 104 and the output terminal of the sensor array 103, respectively. The output terminal of the sampling module 105 is electrically connected to the input terminal of the controller 106.

[0036] The controller 106 is used to generate a path switching instruction based on a preset sampling time slice and send it to the first analog multiplexer 101, determine the target sensor sampling channel based on the preset sampling time slice, and generate an excitation level switching instruction based on the target sensor sampling channel and send it to the multi-range constant current excitation source module 102; the multi-range constant current excitation source module 102 is used to switch to the target constant current level corresponding to the target sensor sampling channel based on the excitation level switching instruction. The first analog multiplexer 101 is used to switch to the input terminal of the reference resistor array 104 or the input terminal of the sensor array 103 according to the path switching command; the second output terminal of the reference resistor array 104 is connected to the analog reference terminal (not shown in the figure). When the first analog multiplexer 101 switches to the reference resistor array 104, a closed current loop of the BIT path is formed. The sampling module 105 is used to acquire the first sampled voltage value of the sensor array 103 and transmit it to the controller 106 when the first analog multiplexer 101 is electrically connected to the input terminal of the sensor array 103; and to acquire the second sampled voltage value of the reference resistor array 104 and transmit it to the controller 106 when the first analog multiplexer 101 is electrically connected to the input terminal of the reference resistor array 104, so that the controller 106 compensates the first sampled voltage value with voltage compensation parameters determined according to the second sampled voltage value at the target constant current level.

[0037] The sensor array may include multiple resistive sensors, each of which can be used to measure a physical quantity of different ranges. Optionally, the resistive sensor may be a resistive temperature sensor, which can be used for temperature measurement of aircraft power, electromechanical or avionics equipment.

[0038] In some embodiments, the plurality of resistive sensors may include: low-resistance sensors, medium-resistance sensors, high-resistance sensors, etc. Of course, this application does not limit the specific resistance value of each sensor, and can be flexibly set according to the actual application scenario. Optionally, one resistive sensor may correspond to one sensor sampling channel.

[0039] The reference resistor array may include at least three reference resistors, each of which may be a precision resistor. For example, it may include a low-resistance reference resistor, a medium-resistance reference resistor, and a high-resistance reference resistor. Each reference resistor serves as a known object of measurement in the reference detection link and can be used to measure the measurement error caused by excitation source drift and sampling module system deviation in the multi-channel sampling circuit, so that the controller can compensate for the first voltage value acquired by the sensor acquisition link accordingly.

[0040] The multi-range constant current excitation source module can output constant current excitation of different amplitudes, such as low current range, medium current range, and high current range. Under the control of the controller, the multi-range constant current excitation source module can provide constant current excitation of corresponding amplitude according to the resistance range of the target resistive sensor corresponding to the target sensor sampling channel, so as to adapt to the acquisition of target resistive sensors with different resistance ranges.

[0041] The path switching instructions can include: path switching instructions to switch to the sensor acquisition link and path switching instructions to switch to the reference detection link.

[0042] In some implementations, the controller can acquire the current time in real time, compare the current time with a preset sampling time slice, and generate a path switching command to switch to the sensor acquisition link or a path switching command to switch to the reference detection link based on the comparison result. Specifically, if the current time is within the preset sampling time slice, a path switching command to switch to the sensor acquisition link is generated; if the current time is within an idle sampling time slice, a path switching command to switch to the reference detection link is generated.

[0043] In some implementations, the controller can determine the target sensor sampling channel by polling according to a preset sampling time slice. The preset sampling time slice can be understood as the polling time of the sensor sampling channel. The target sensor sampling channel can be the sampling channel corresponding to any resistive sensor in the sensor array, which can be determined according to specific polling rules.

[0044] Optionally, if the controller determines the target sensor sampling channel based on a preset sampling time slice, it can determine the target constant current level based on the resistance range of the resistive sensor in that target sensor sampling channel. Based on this target constant current level, an excitation level switching command can be generated and sent to the multi-range constant current excitation source module. The excitation level switching command is used to instruct the multi-range constant current excitation source module to switch to the target constant current level.

[0045] Meanwhile, if the controller generates a path switching command to switch to the sensor acquisition link, the first analog multiplexer can switch to electrical connection with the input of the sensor array within a preset sampling time slice according to the path switching command.

[0046] It is understandable that when the first analog multiplexer is switched to be electrically connected to the input terminal of the sensor array, the controller, the first analog multiplexer, the multi-range constant current excitation source module, the sensor array, and the sampling module will form a sensor acquisition link. At this time, the sampling module can acquire the first sampled voltage value of the sensor array and transmit it to the controller.

[0047] If the controller generates a path switching command to switch to the reference detection link, the first analog multiplexer can switch to electrical connection with the input of the reference detection link according to the path switching command during the sampling idle time slice.

[0048] Understandably, when the first analog multiplexer is switched to be electrically connected to the input terminal of the reference resistor array, the controller, the first analog multiplexer, the multi-range constant current excitation source module, the reference resistor array, and the sampling module will form a reference detection link. The second output terminal of the reference resistor array is connected to the analog reference terminal, so that the constant current excitation output by the multi-range constant current excitation source module can form a closed current loop through the first analog multiplexer, the selected reference resistor, and the analog reference terminal. At this time, the sampling module can collect the second sampling voltage value of the reference detection link and transmit it to the controller.

[0049] Furthermore, after obtaining the second and first sampled voltage values ​​at the target constant current level, relevant voltage compensation parameters can be calculated based on the second sampled voltage value. These voltage compensation parameters characterize the measurement errors caused by excitation source drift and sampling module system deviation in the multi-channel sampling circuit. The first sampled voltage value can then be compensated based on these voltage compensation parameters to obtain a compensated first sampled voltage value, thereby improving the accuracy of the sampling results and the reliability of the multi-channel acquisition circuit.

[0050] As can be seen, in the multi-channel acquisition circuit provided in this application embodiment, by setting the sensor acquisition link and the reference detection link to be consistent in the excitation path and sampling path, and changing the object under test only by the first analog multiplexer, the measurement function and the detection function can be unified. Compared with setting an independent calibration branch, it can improve the consistency between the BIT detection result and the actual measurement link status, improve the self-test coverage capability, and help improve the accuracy, integration and security of airborne system key parameter monitoring.

[0051] Figure 2 This is a schematic diagram of a functional module of another multi-channel acquisition circuit applied to an airborne system, provided as an embodiment of this application. In optional implementations, such as... Figure 2 As shown, the sensor array includes multiple resistive sensors. The multi-channel acquisition circuit also includes a second analog multiplexer 109. The control terminal of the second analog multiplexer 109 is electrically connected to the third output terminal of the controller 106. The multiple independent channel output terminals of the second analog multiplexer 109 are respectively electrically connected to one end of each of the multiple resistive sensors in the sensor array. The common terminal of the second analog multiplexer 109 is connected to the analog reference terminal AGND. The controller 106 is also used to generate a channel switching command according to a preset sampling time slice and send it to the second analog multiplexer; the second analog multiplexer 109 is used to control the sensor array to switch to the target sensor sampling channel according to the channel switching command.

[0052] In some implementations, when making the connection, the control terminal of the second analog multiplexer (e.g., the address control terminal) and the third output terminal of the controller (e.g., the GPIO pin terminal) can be electrically connected.

[0053] In some implementations, the sensor array may include multiple resistive sensors, and the second analog multiplexer may have multiple independent channel outputs and a common terminal. Each independent channel output can be connected to the low-end reference node of each resistive sensor, and the common terminal can be connected to the analog reference terminal. Of course, this application does not limit the number of independent channel outputs in the second analog multiplexer; depending on the actual application scenario, it can be set to 8, 16, etc.

[0054] Optionally, during channel switching, the controller can poll multiple sensor sampling channels of the sensor array according to a preset sampling time slice to determine the target sensor sampling channel, generate a channel switching command based on the target sensor sampling channel, and select one of the independent channel output terminals and the common terminal corresponding to the target sensor sampling channel to connect the low-end reference node and the analog reference terminal of the target resistive sensor corresponding to the currently selected target sensor sampling channel.

[0055] Optionally, during specific sampling, the input end of the sensor array can be regarded as a high-end sampling node, and the output end of the sensor array can be regarded as a low-end sampling node. When the first sampling voltage value of the sensor array is acquired by the sampling module, the current sensor resistance value of the sensor array can be calculated based on the voltage drop between the high-end sampling node and the low-end sampling node. This eliminates the need to consider the setting of the second analog multiplexer during the sampling process, and avoids the influence of the on-resistance and temperature drift of the second analog multiplexer on the sampling results.

[0056] It can be understood that the multiple independent channel outputs of the second analog multiplexer are electrically connected to one end of each of the multiple resistive sensors in the sensor array, and the second analog multiplexer is grounded, forming a gating loop at the low potential end. That is, the second analog multiplexer is connected between the low potential end and the analog reference end, so that the common loop of all sensors in the sensor array converges here. Then, by controlling the address gating signal of the second analog multiplexer, the physical time-division gating of multiple channels can be realized.

[0057] By applying the embodiments of this application, by setting the sampling module and the second analog multiplexer to form a single-channel conditioning multiplexing structure, the number of repeated conditioning circuits can be reduced, which is beneficial to reducing the circuit board area and the workload of inter-channel consistency debugging, and reducing the occupation of hardware resources.

[0058] In an optional implementation, the controller is specifically configured to generate a first path switching instruction based on a preset sampling time slice and send it to the first analog multiplexer, or to determine a sampling idle time slice based on the preset sampling time slice, generate a periodic BIT self-test instruction based on the sampling idle time slice, and generate a second path switching instruction based on the periodic BIT self-test instruction and send it to the first analog multiplexer. A first analog multiplexer is used to switch to electrical connection with the input terminal of the sensor array within a preset sampling time slot according to a first path switching instruction, or to switch to electrical connection with the input terminal of the reference resistor array during a sampling idle time slot according to a second path switching instruction to perform periodic BIT detection.

[0059] Specifically, when generating path switching instructions, the path switching instruction to the sensor acquisition link can be recorded as the first path switching instruction, and the path switching instruction to the reference detection link can be regarded as the second path switching instruction.

[0060] In some implementations, if the current time falls within a sampling idle time slice (i.e., the switching interval), a periodic BIT self-test instruction can be generated, and a second path switching instruction can be further generated based on this periodic BIT self-test instruction. The process of path switching based on the first and second path switching instructions can be found in the foregoing descriptions and will not be repeated here.

[0061] In an optional implementation, the controller is further configured to acquire a fault self-test command or a power-on self-test command, generate a second path switching command based on the fault self-test command or the power-on self-test command, and send it to the first analog multiplexer; the first analog multiplexer is configured to switch to an electrical connection with the input terminal of the reference resistor array based on the second path switching command to perform fault BIT detection or power-on BIT detection.

[0062] Optionally, the controller can be configured to generate a power-on self-test command after power-on initialization is completed; the controller can also communicate with a host computer via a bus interface to receive fault self-test commands from the host computer.

[0063] When the controller receives a fault self-test command, it can generate a second path switching command that indicates switching to the reference detection link and send it to the first analog multiplexer. The first analog multiplexer then switches to an electrical connection with the input of the reference resistor array to perform fault BIT detection. When the controller receives a power-on self-test command, it can generate a second path switching command and send it to the first analog multiplexer. The first analog multiplexer then switches to an electrical connection with the input of the reference resistor array to perform power-on BIT detection.

[0064] Understandably, fault bit detection or power-on bit detection can be performed based on a reference detection link consisting of the controller, multi-range constant current excitation source module, first analog multiplexer, reference resistor array, and sampling module. By performing fault bit detection or power-on bit detection, various anomalies such as excitation drift and sampling gain deviation can be identified in a timely manner, allowing the controller to update voltage compensation parameters promptly and improving the reliability of the multi-channel acquisition circuit.

[0065] Figure 3 This application provides a flowchart illustrating a multi-channel data acquisition method for an airborne system. In optional implementations, such as... Figure 3 As shown, the controller compensates the first sampled voltage value using voltage compensation parameters determined based on the second sampled voltage value at the target constant current level, including: S301. The controller calculates the voltage compensation parameters based on the second sampled voltage value and the theoretical reference voltage corresponding to the target constant current level.

[0066] S302. Compensate the first sampled voltage value according to the voltage compensation parameters and output the compensated first sampled voltage value.

[0067] The second sampling voltage value can be acquired when the first analog multiplexer is electrically connected to the input terminal of the reference resistor array, and it can be regarded as the reference readback voltage.

[0068] The theoretical reference voltage corresponding to the target constant current range can be calculated by multiplying the calibrated excitation current corresponding to the target constant current range with the resistance value of the reference resistor selected in the reference resistor array.

[0069] Alternatively, the voltage compensation parameters can be measured using equivalent gain parameters, zero-point offset parameters, etc. In some implementations, the voltage compensation parameters can be calculated using the following formula:

[0070] in, This indicates the second sampled voltage value. Represents the equivalent gain parameter. This represents the zero-position offset parameter. This indicates the theoretical reference voltage corresponding to the target constant current level.

[0071] In some implementations, the equivalent gain parameter The following formula can be used to calculate it:

[0072] in, This represents the second sampled voltage value when the reference resistor array selects the first reference resistor at the target constant current level. This represents the second sampled voltage value when the reference resistor array selects the second reference resistor at the target constant current level. This indicates the theoretical reference voltage corresponding to the selection of the first reference resistor in the reference resistor array at the target constant current level. This indicates the theoretical reference voltage when the reference resistor array selects the second reference resistor under the target constant current range. The first and second reference resistors are two reference resistors with different resistance values ​​in the reference resistor array.

[0073] It is understandable that in calculating and determining the equivalent gain parameters... Then, the zero-position offset parameter can be calculated using the formula described above. .

[0074] Optionally, after calculating the equivalent gain parameter and the zero-position offset parameter, the first sampled voltage value can be compensated using the following formula to output the compensated first sampled voltage value. The compensation formula is as follows:

[0075] in, This represents the first sampled voltage value after compensation. This represents the first sampled voltage value. Represents the equivalent gain parameter. This represents the zero offset parameter.

[0076] Optionally, the controller is also used to determine the resistance value of the target resistive sensor corresponding to the target sensor sampling channel based on the compensated first sampling voltage value and the calibration excitation current corresponding to the target constant current range.

[0077] In some implementations, the resistance value of the target resistive sensor corresponding to the target sensor sampling channel can be calculated using the following formula:

[0078] Where R represents the resistance value of the target resistive sensor. This represents the first sampled voltage value after compensation, and I represents the calibrated excitation current corresponding to the target constant current range.

[0079] Optionally, when the target resistive sensor is a temperature-sensing resistor, the controller can further convert the resistance value of the target resistive sensor into a temperature value by calling the corresponding resistance-temperature relationship, lookup table, or calibration curve according to the resistance value of the target resistive sensor.

[0080] Of course, it should be noted that the corresponding voltage compensation parameters may differ for different constant current ranges. Using the embodiments of this application, it is possible to correct the equivalent gain error and zero-point offset introduced by the sensor acquisition link consisting of the multi-range constant current excitation source module, the first analog multiplexer, and the sampling module through voltage compensation parameters.

[0081] Optionally, the controller is further configured to calculate a normalized link deviation based on the second sampled voltage value and the theoretical reference voltage corresponding to the target constant current level; and to evaluate the health status of the sensor acquisition link based on the normalized link deviation.

[0082] In some implementations, the normalized link deviation ΔE can be calculated using the following formula:

[0083] in, This is the second sampled voltage value. The theoretical reference voltage corresponding to the target constant current level. This is the full-scale input voltage corresponding to the analog-to-digital conversion module in the sampling module.

[0084] In some implementations, when the normalized link deviation ΔE meets the preset deviation threshold range, the controller can update the voltage compensation parameters for the corresponding constant current level using the method described above.

[0085] Optionally, when the normalized link deviation does not exceed the preset deviation threshold range, the health status of the sensor acquisition link determined based on the normalized link deviation assessment can be considered normal. When the normalized link deviation exceeds the preset deviation threshold range, the controller can maintain the most recent voltage compensation parameters, and the health status of the sensor acquisition link based on the normalized link deviation assessment can be classified as degraded, failed, or faulty. The assessed health status may vary depending on the application scenario. Specifically, a smaller ΔE indicates that the actual reference readback voltage is closer to the theoretical reference voltage, the sensor acquisition link is closer to the reference state, and the health level is higher; a larger ΔE indicates that the sensor acquisition link deviation is more significant, and the health level is lower. Specific assessment methods are detailed in Table 1 below. Table 1

[0086] As shown in Table 1, the first threshold, the second threshold, and the third threshold can be configured according to the system accuracy requirements, the BIT detection strategy, and the security analysis results, and the first threshold must be less than the second threshold, and the second threshold must be less than the third threshold.

[0087] Optionally, if ΔE ≤ the first threshold, it indicates that the health status of the acquisition link in the multi-channel acquisition circuit is normal. In this case, the compensated first sampled voltage value can be output, and online compensation can be performed using the method described above. If the first threshold < ΔE ≤ the second threshold, it indicates that the health status of the acquisition link in the multi-channel acquisition circuit is degraded. In this case, the most recent valid compensation parameter can be retained, and a degradation flag can be added while outputting the compensated first sampled voltage value for identification by the host system. Maintenance can be performed promptly based on the identification result. If the second threshold < ΔE ≤ the third threshold, it indicates that the health status of the acquisition link in the multi-channel acquisition circuit is failed. At this point, updating the relevant channel data can be stopped, or a safe default value can be output. The safe default value can be determined based on the monitored object and the security policy of the host system. For example, for temperature signals, a preset safe temperature value, the last reliable value, or an invalid flag can be used. If ΔE > the third threshold, it indicates that the health status level of the acquisition link in the multi-channel acquisition circuit is faulty. At this point, a fault reporting or redundancy switching mechanism can be triggered. There are no restrictions here, and the choice can be made flexibly according to the actual application scenario. This can help identify hidden faults such as drift and changes in the gain of the analog-to-digital conversion module, and provide a basis for the host system to perform data shielding, alarms, or redundancy switching.

[0088] In some implementations, the controller may also be configured to encapsulate the first sampled voltage value obtained under the normal measurement path and the corresponding health status flag into an airborne communication message that can be transmitted via the CAN bus, and upload it to the flight control computer or airborne management equipment, so that the flight control computer or airborne management equipment can quickly identify the reliability of the channel data and the subsequent processing strategy based on the health status flag.

[0089] The health status flag can be determined according to the health status level. Optionally, the health status flag can use at least two bits to represent different health status levels. For example, 00 represents the Normal status, 01 represents the Degraded status, 10 represents the Invalid status, and 11 represents the Critical status. In other embodiments, an enumeration field, status word, or fault code field can also be used to represent the status level, which is not limited here.

[0090] Optionally, if any channel remains in an "Invalid" state for a preset number of consecutive frames, the controller can be configured to discard the signal and switch to a backup sensor link.

[0091] In an optional implementation, the controller is further configured to determine whether the first sampled voltage value is less than the preset linear lower limit threshold corresponding to the sampling module based on the voltage outer loop algorithm; if so, a shift request is generated. Determine whether the first sampled voltage value is greater than the preset linear upper limit threshold corresponding to the sampling module. If so, generate a downshifting request. After the controller determines that the upshift or downshift request is allowed based on the stability inner loop algorithm, it sends an upshift or downshift command to the multi-range constant current excitation source module.

[0092] The preset linear lower threshold and preset linear upper threshold of the sampling module define the optimal linear operating range of the sampling module. An upshift request is used to request switching to a constant current range with a higher output current, while a downshift request is used to request switching to a constant current range with a lower output current.

[0093] Optionally, the sampling module may include a differential sampling circuit and an analog-to-digital conversion module. The optimal linear operating range of the sampling module may be determined by the performance parameters of the analog-to-digital conversion module. For example, it may be 10% to 90% of the full scale of the analog-to-digital conversion module. The specific range (10% to 90%) may be configured according to the input range of the analog-to-digital conversion module and the system accuracy requirements.

[0094] It is understandable that when the optimal linear operating range of the sampling module is 10% to 90% of the full scale of the analog-to-digital converter module, the preset lower linear threshold can be 10% of the full scale of the analog-to-digital converter module, and the preset upper linear threshold can be 90% of the full scale of the analog-to-digital converter module.

[0095] In some implementations, if the voltage outer loop algorithm determines that the first sampled voltage value is less than a preset linear lower threshold, the controller, after determining permission based on the stability inner loop algorithm, sends an upshift switching command to the multi-range constant current excitation source module. If the voltage value is greater than the preset linear upper threshold, the controller, after determining permission based on the stability inner loop algorithm, sends a downshift switching command to the multi-range constant current excitation source module. Thus, the multi-range constant current excitation source module can adjust the upshift according to the upshift switching command, or adjust the downshift according to the downshift switching command, thereby achieving adaptive gear adjustment.

[0096] Figure 4 This is a flowchart illustrating another multi-channel data acquisition method for airborne systems provided in an embodiment of this application. In optional implementations, such as... Figure 4 As shown, the controller is also used for: S401. After generating an upshift request, obtain the first sampling sequence of the sensor array within a first preset historical time period based on the stability inner loop algorithm; or, after generating a downshift request, obtain the second sampling sequence of the sensor array within a first preset historical time period based on the stability inner loop algorithm.

[0097] S402. Generate an upshift switching command based on the first sampling sequence and send it to the multi-range constant current excitation source module, or generate a downshift switching command based on the second sampling sequence and send it to the multi-range constant current excitation source module.

[0098] In some implementations, considering that the airborne system will generate severe mechanical vibrations during eVTOL takeoff and landing, tilting, or high-load operation of the motor, the sensor connection parts may be affected by vibration or electromagnetic interference, causing the first sampling voltage value to fluctuate in a short period of time. Therefore, the controller, based on the above-mentioned voltage outer loop algorithm, can also combine the stability inner loop algorithm for secondary judgment to determine whether to generate an upshift or downshift switching command. This effectively prevents range skipping and signal oscillation caused by environmental noise, and significantly enhances the data stability of the multi-channel sampling circuit provided in this application under extreme aviation conditions.

[0099] Optionally, taking the generation of a shift-up command as an example, the controller is further configured to, when determining that the first sampled voltage value is less than the preset linear lower limit threshold corresponding to the sampling module, obtain the first sampled sequence of the sensor array within a first preset historical time period based on the sliding window length N using a stability inner loop algorithm, calculate the evaluation parameters of the first sampled sequence, which can reflect the fluctuation of the first sampled sequence. If the evaluation parameters meet the preset requirements (e.g., the standard deviation is less than the preset standard deviation threshold), then a shift-up command is generated and sent to the multi-range constant current excitation source module, effectively preventing range jumps and signal oscillations caused by environmental noise, and significantly enhancing the data stability of the multi-channel sampling circuit provided in this application under extreme aviation conditions.

[0100] The sliding window length N can be set according to the channel sampling period, sensor response time, allowable shift response delay, etc. Optionally, N can be an integer greater than or equal to 3, for example, between 4 and 16, to balance the ability to resist transient interference and response speed.

[0101] For example, the evaluation parameters of the first sampling sequence may include variance, standard deviation, etc., which are not limited here and can be flexibly selected according to the actual application scenario.

[0102] The process of generating a downshifting instruction based on the second sampling sequence and sending it to the multi-range constant current excitation source module can be found in the relevant description of the upshifting instruction mentioned above, and will not be repeated here.

[0103] Figure 5 This is a flowchart illustrating another multi-channel data acquisition method for airborne systems provided in an embodiment of this application. In optional implementations, such as... Figure 5 As shown, the controller is specifically used for: S501. Calculate the first variance value based on the first sampling sequence, or calculate the second variance value based on the second sampling sequence.

[0104] S502. If the first variance value is determined to be less than the first variance threshold, an upshift switching instruction is generated and sent to the multi-range constant current excitation source module; if the first variance value is greater than or equal to the first variance threshold, the current constant current level is maintained; if the second variance value is determined to be less than the second variance threshold, an downshift switching instruction is generated and sent to the multi-range constant current excitation source module; if the second variance value is greater than or equal to the second variance threshold, the current constant current level is maintained.

[0105] In some implementations, the evaluation parameter can be selected as variance. For the first sampling sequence, a first variance value can be calculated, and the relationship between the first variance value and a first variance threshold is compared. If the first variance value is less than the first variance threshold, it indicates that the fluctuation of the first sampling sequence is relatively smooth, meaning that the current target sensor sampling channel fluctuates less within the sliding window. In this case, an upgrade switching command can be generated and sent to the multi-range constant current excitation source module. The first variance threshold can be set based on empirical values.

[0106] It should be noted that if the first variance value is greater than or equal to the first variance threshold, the current sampled signal is determined to be in a state of strong fluctuation (such as vibration or electromagnetic interference). At this time, the range switching command is blocked to avoid frequent switching of the range under unstable operating conditions.

[0107] For details on the process of calculating the second variance value based on the second sampling sequence and generating a downshifting instruction to send to the multi-range constant current excitation source module, please refer to the relevant description of the upshifting instruction mentioned above, which will not be repeated here.

[0108] By applying the embodiments of this application and introducing the voltage outer loop algorithm and the stability inner loop algorithm, frequent range switching can be suppressed during sampling signal fluctuations. This is beneficial to improving the data continuity under complex airborne electromagnetic and vibration environments and improving the range stability under dynamic operating conditions, thus providing uninterrupted accuracy assurance in complex airborne electromagnetic environments.

[0109] In alternative implementations, such as Figure 2 As shown, the sampling module 105 includes a differential sampling circuit 107 and an analog-to-digital converter module 108. The sampling terminals of the reference resistor array 104 and the sensor array 103 are electrically connected to the input terminals of the differential sampling circuit 107, respectively. The output terminal of the differential sampling circuit 107 is electrically connected to the input terminal of the analog-to-digital converter module 108, and the output terminal of the analog-to-digital converter module 108 is electrically connected to the input terminal of the controller 106. The differential sampling circuit 107 and the second analog multiplexer 109 form a single-channel conditioning multiplexing structure for polling and acquiring the quasi-static resistance signal output by the resistive temperature sensor in the sensor array 103.

[0110] It is understandable that when the sampling module includes a differential sampling circuit and an analog-to-digital conversion module, the aforementioned voltage compensation parameter can characterize the measurement error in the multi-channel sampling circuit caused by excitation source drift, differential sampling circuit offset, and zero-position or gain error of the analog-to-digital conversion module.

[0111] In this process, it is understood that the differential sampling circuit can acquire the differential analog signals of the reference resistor array and sensor array, and perform gain conditioning, noise filtering and voltage protection on them. Then, it inputs the analog voltage to the analog-to-digital conversion module. The analog-to-digital conversion module receives the analog voltage output by the differential sampling circuit, converts it into a digital sample value and transmits it to the controller to realize the sampling.

[0112] In an optional implementation, the reference resistor array includes at least three reference resistors, which at least indicate: a low-resistance reference resistor, a medium-resistance reference resistor, and a high-resistance reference resistor, for use as a known test object during BIT testing; the multi-range constant current excitation source module includes multiple controlled constant current output branches, each of which is equipped with an independent precision feedback resistor for outputting the output current of the corresponding constant current range.

[0113] In some implementations, each reference resistor may be a precision low-temperature drift resistor, the accuracy class and temperature drift index of which are determined according to the system measurement accuracy requirements.

[0114] Since the controller can compensate the first sampled voltage value using voltage compensation parameters determined based on the second sampled voltage value at the target constant current level, and considering that a single reference resistor can only calibrate a single operating point and cannot characterize the excitation source output deviation, sampling gain deviation, and analog-to-digital conversion error corresponding to low-resistance, medium-resistance, and high-resistance sensors in the sensor array, this application sets the reference resistor array to include at least three reference resistors to be applicable to compensation for low-resistance, medium-resistance, and high-resistance sensors, thereby improving the reliability of compensation.

[0115] Optionally, the multi-range constant current excitation source module can be configured with multiple independent controlled constant current output branches. Each branch can be equipped with a precision feedback resistor to form a closed-loop current negative feedback. By matching feedback resistors with different resistance values, the output current of a single branch is precisely limited, so that each branch can stably output low, medium and high constant current excitation levels. This achieves multi-level adjustable constant current excitation output, meeting the differentiated sampling excitation requirements of low-resistance, medium-resistance and high-resistance sensors and reference resistor arrays.

[0116] In an optional implementation, the sensor array includes at least one of the following: NTC thermistor, PTC thermistor, and platinum resistance thermometer.

[0117] Optionally, the sensor array can be selected from at least one type of temperature-sensing resistor, such as NTC thermistor, PTC thermistor, or platinum resistance thermometer. No limitation is imposed here, and the appropriate type can be selected flexibly according to the actual application scenario.

[0118] In some implementations, the multi-channel acquisition circuit described above can also be equipped with a symmetrical RC anti-aliasing filter network. The anti-aliasing filter network is located between the sampling node and the input of the differential sampling circuit to attenuate high-frequency interference components that are higher than the effective signal bandwidth before the analog-to-digital conversion module samples, thus preventing such high-frequency interference from folding into low-frequency errors during discrete sampling.

[0119] The cutoff frequency of the anti-aliasing filter network can be determined based on the sensor signal bandwidth, sampling frequency, channel polling period, and system response time.

[0120] Figure 6 This is a flowchart illustrating another multi-channel acquisition method for airborne systems provided in this application embodiment. This multi-channel acquisition method can be applied to the controller in the multi-channel acquisition circuit of an airborne system as described in any of the foregoing embodiments. The basic principle and technical effects of this method are the same as those in the corresponding circuit embodiments described above. For the sake of brevity, parts not mentioned in this embodiment can be referred to the corresponding content in the foregoing embodiments. Figure 6 As shown, the method includes: S601. Generate a path switching instruction based on the preset sampling time slice and send it to the first analog multiplexer. Determine the target sensor sampling channel based on the preset sampling time slice. Generate an excitation level switching instruction based on the target sensor sampling channel and send it to the multi-range constant current excitation source module.

[0121] The multi-range constant current excitation source module switches to the target constant current range corresponding to the target sensor sampling channel according to the excitation range switching command; the first analog multiplexer is used to switch to the input terminal of the reference resistor array or the input terminal of the sensor array according to the path switching command. S602. When the first analog multiplexer is electrically connected to the input terminal of the sensor array, the first sampled voltage value of the sensor array is obtained through the sampling module. When the first analog multiplexer is electrically connected to the input terminal of the reference resistor array, the second sampled voltage value of the reference resistor array is obtained through the sampling module.

[0122] S603. Under the target constant current setting, the first sampled voltage value is compensated using the voltage compensation parameters determined based on the second sampled voltage value.

[0123] In an optional implementation, the controller is further configured to determine the resistance value of the target resistive sensor corresponding to the target sensor sampling channel based on the compensated first sampling voltage value and the calibration excitation current corresponding to the target constant current level.

[0124] In an optional implementation, the controller is further configured to determine whether the first sampled voltage value is less than the preset linear lower limit threshold corresponding to the sampling module based on the voltage outer loop algorithm; if so, a shift request is generated. Determine whether the first sampled voltage value is greater than the preset linear upper limit threshold corresponding to the sampling module. If so, generate a downshifting request. After the controller determines that the upshift or downshift request is allowed based on the stability inner loop algorithm, it sends an upshift or downshift command to the multi-range constant current excitation source module.

[0125] In an optional implementation, the controller is further configured to, after generating the upshift request, obtain a first sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm; or, after generating the downshift request, obtain a second sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm. A shift-up instruction is generated based on the first sampling sequence and sent to the multi-range constant current excitation source module; or a shift-down instruction is generated based on the second sampling sequence and sent to the multi-range constant current excitation source module.

[0126] In an optional implementation, the controller is specifically configured to calculate a first variance value based on the first sampling sequence, or to calculate a second variance value based on the second sampling sequence; If the first variance value is determined to be less than the first variance threshold, an upshift switching command is generated and sent to the multi-range constant current excitation source module; if the first variance value is greater than or equal to the first variance threshold, the current constant current level is maintained; if the second variance value is determined to be less than the second variance threshold, an downshift switching command is generated and sent to the multi-range constant current excitation source module; if the second variance value is greater than or equal to the second variance threshold, the current constant current level is maintained.

[0127] By applying the embodiments of this application and introducing the voltage outer loop algorithm and the stability inner loop algorithm, frequent range switching can be suppressed during sampling signal fluctuations. This is beneficial to improving the data continuity under complex airborne electromagnetic and vibration environments and improving the range stability under dynamic operating conditions, thus providing uninterrupted accuracy assurance in complex airborne electromagnetic environments.

[0128] Optionally, this application provides an airborne device, including a multi-channel acquisition circuit for an airborne system as described in any of the foregoing embodiments. The basic principle and technical effects of this airborne device are the same as those of the corresponding circuit embodiments described above. For the sake of brevity, parts not mentioned in this embodiment can be referred to the corresponding content in the foregoing embodiments, and will not be repeated here.

[0129] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0130] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0131] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0132] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0133] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0134] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A multi-channel data acquisition circuit for airborne systems, characterized in that, include: The system comprises an analog multiplexer, a multi-range constant current excitation source module, a sensor array, a reference resistor array, a sampling module, and a controller. The control terminal of the first analog multiplexer and the input terminal of the multi-range constant current excitation source module are electrically connected to the first output terminal and the second output terminal of the controller, respectively. The first analog multiplexer includes a common terminal and multiple selectable channels. The common terminal is electrically connected to the output terminal of the multi-range constant current excitation source module. At least one of the multiple selectable channels is electrically connected to the input terminal of the sensor array, and the remaining multiple selectable channels are electrically connected to the input terminal of the reference resistor array, respectively. The first sampling terminal of the sampling module is electrically connected to the input terminal of the reference resistor array and the input terminal of the sensor array, respectively. The second sampling terminal of the sampling module is electrically connected to the first output terminal of the reference resistor array and the output terminal of the sensor array, respectively. The output terminal of the sampling module is electrically connected to the input terminal of the controller. The controller is configured to generate a path switching instruction based on a preset sampling time slice and send it to the first analog multiplexer, determine the target sensor sampling channel based on the preset sampling time slice, and generate an excitation level switching instruction based on the target sensor sampling channel and send it to the multi-range constant current excitation source module. The multi-range constant current excitation source module is used to switch to the target constant current level corresponding to the target sensor sampling channel according to the excitation level switching command; The first analog multiplexer is used to switch to an electrical connection with either the input terminal of the reference resistor array or the input terminal of the sensor array according to the path switching instruction. The second output terminal of the reference resistor array is connected to the analog reference terminal. When the first analog multiplexer switches to the reference resistor array, a closed current loop of the BIT path is formed. The sampling module is used to acquire a first sampled voltage value of the sensor array and transmit it to the controller when the first analog multiplexer is electrically connected to the input terminal of the sensor array; and to acquire a second sampled voltage value of the reference resistor array and transmit it to the controller when the first analog multiplexer is electrically connected to the input terminal of the reference resistor array, so that the controller can compensate the first sampled voltage value using a voltage compensation parameter determined according to the second sampled voltage value at the target constant current level.

2. The multi-channel acquisition circuit according to claim 1, characterized in that, The sensor array includes multiple resistive sensors. The multi-channel acquisition circuit further includes a second analog multiplexer. The control terminal of the second analog multiplexer is electrically connected to the third output terminal of the controller. The multiple independent channel output terminals of the second analog multiplexer are respectively electrically connected to one end of each of the multiple resistive sensors in the sensor array. The common terminal of the second analog multiplexer is connected to an analog reference terminal. The controller is also configured to generate a channel switching instruction based on a preset sampling time slice and send it to the second analog multiplexer; The second analog multiplexer is used to control the sensor array to switch to the target sensor sampling channel according to the channel switching command.

3. The multi-channel acquisition circuit according to claim 1, characterized in that, The controller is specifically configured to generate a first path switching instruction based on a preset sampling time slice and send it to the first analog multiplexer, or to determine a sampling idle time slice based on the preset sampling time slice, generate a periodic BIT self-test instruction based on the sampling idle time slice, and generate a second path switching instruction based on the periodic BIT self-test instruction and send it to the first analog multiplexer. The first analog multiplexer is configured to switch to electrical connection with the input terminal of the sensor array during the preset sampling time slice according to the first path switching instruction, or to switch to electrical connection with the input terminal of the reference resistor array during the sampling idle time slice according to the second path switching instruction to perform periodic BIT detection.

4. The multi-channel acquisition circuit according to claim 1, characterized in that, The controller is also used to acquire a fault self-test command or a power-on self-test command, generate a second path switching command based on the fault self-test command or the power-on self-test command, and send it to the first analog multiplexer. The first analog multiplexer is configured to switch to an electrical connection with the input of the reference resistor array according to the second path switching instruction to perform fault BIT detection or power-on BIT detection.

5. The multi-channel acquisition circuit according to claim 1, characterized in that, The controller compensates the first sampled voltage value at the target constant current level using voltage compensation parameters determined based on the second sampled voltage value, including: The controller calculates voltage compensation parameters based on the second sampled voltage value and the theoretical reference voltage corresponding to the target constant current level; The first sampled voltage value is compensated according to the voltage compensation parameters, and the compensated first sampled voltage value is output.

6. The multi-channel acquisition circuit according to claim 5, characterized in that, The controller is also used to determine the resistance value of the target resistive sensor corresponding to the target sensor sampling channel based on the compensated first sampling voltage value and the calibration excitation current corresponding to the target constant current level.

7. The multi-channel acquisition circuit according to claim 1, characterized in that, The controller is also used to calculate the normalized link deviation based on the second sampled voltage value and the theoretical reference voltage corresponding to the target constant current level. The health status of the acquisition link is assessed based on the normalized link deviation.

8. The multi-channel acquisition circuit according to claim 1, characterized in that, The controller is also used to determine whether the first sampled voltage value is less than the preset linear lower limit threshold corresponding to the sampling module according to the voltage outer loop algorithm. If so, a shift request is generated. Determine whether the first sampled voltage value is greater than the preset linear upper limit threshold corresponding to the sampling module. If so, generate a downshifting request. After the controller determines that the upshift or downshift request is allowed based on the stability inner loop algorithm, it sends an upshift or downshift command to the multi-range constant current excitation source module.

9. The multi-channel acquisition circuit according to claim 8, characterized in that, The controller is further configured to, after generating the upshift request, obtain a first sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm; or, after generating the downshift request, obtain a second sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm. A shift-up instruction is generated based on the first sampling sequence and sent to the multi-range constant current excitation source module; or a shift-down instruction is generated based on the second sampling sequence and sent to the multi-range constant current excitation source module.

10. The multi-channel acquisition circuit according to claim 9, characterized in that, The controller is specifically configured to calculate a first variance value based on the first sampling sequence, or to calculate a second variance value based on the second sampling sequence; If it is determined that the first variance value is less than the first variance threshold, an upgrade switching instruction is generated and sent to the multi-range constant current excitation source module; If the first variance value is greater than or equal to the first variance threshold, then maintain the current constant current level; If it is determined that the second variance value is less than the second variance threshold, a downshifting switching instruction is generated and sent to the multi-range constant current excitation source module; If the second variance value is greater than or equal to the second variance threshold, then maintain the current constant current level.

11. The multi-channel acquisition circuit according to claim 2, characterized in that, The sampling module includes: a differential sampling circuit and an analog-to-digital conversion module; The sampling terminals of the reference resistor array and the sensor array are electrically connected to the input terminal of the differential sampling circuit, respectively. The output terminal of the differential sampling circuit is electrically connected to the input terminal of the analog-to-digital converter module, and the output terminal of the analog-to-digital converter module is electrically connected to the input terminal of the controller. The differential sampling circuit and the second analog multiplexer form a single-channel conditioning multiplexing structure for polling and acquiring the quasi-static resistance signal output by the resistive temperature sensor in the sensor array.

12. The multi-channel acquisition circuit according to any one of claims 1-11, characterized in that, The reference resistor array includes at least three reference resistors, which at least indicate: a low-resistance reference resistor, a medium-resistance reference resistor, and a high-resistance reference resistor, for use as a known test object during BIT testing; The multi-range constant current excitation source module includes multiple controlled constant current output branches, each of which is equipped with an independent precision feedback resistor to output the corresponding constant current range.

13. The multi-channel acquisition circuit according to any one of claims 1-11, characterized in that, The sensor array includes at least one of the following: NTC thermistor, PTC thermistor, and platinum resistance thermometer.

14. A multi-channel acquisition method applied to an airborne system, characterized in that, The method comprises: a controller applied in a multi-channel acquisition circuit of an airborne system according to any one of claims 1-13; and the method further comprises: A path switching command is generated based on a preset sampling time slice and sent to the first analog multiplexer. The target sensor sampling channel is determined based on the preset sampling time slice. An excitation level switching command is generated based on the target sensor sampling channel and sent to the multi-range constant current excitation source module. The multi-range constant current excitation source module switches to the target constant current level corresponding to the target sensor sampling channel based on the excitation level switching command. The first analog multiplexer is used to switch to an electrical connection with the input terminal of the reference resistor array or the input terminal of the sensor array based on the path switching command. When the first analog multiplexer is electrically connected to the input terminal of the sensor array, the sampling module obtains the first sampled voltage value of the sensor array; when the first analog multiplexer is electrically connected to the input terminal of the reference resistor array, the sampling module obtains the second sampled voltage value of the reference resistor array. At the target constant current level, the first sampled voltage value is compensated using voltage compensation parameters determined based on the second sampled voltage value.

15. The multi-channel acquisition method according to claim 14, characterized in that, The controller is also used to determine whether the first sampled voltage value is less than the preset linear lower limit threshold corresponding to the sampling module according to the voltage outer loop algorithm. If so, a shift request is generated. Determine whether the first sampled voltage value is greater than the preset linear upper limit threshold corresponding to the sampling module. If so, generate a downshifting request. After the controller determines that the upshift or downshift request is allowed based on the stability inner loop algorithm, it sends an upshift or downshift command to the multi-range constant current excitation source module.

16. The multi-channel acquisition method according to claim 15, characterized in that, The controller is further configured to, after generating the upshift request, obtain a first sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm; or, after generating the downshift request, obtain a second sampling sequence of the sensor array within a first preset historical time period based on a stability inner loop algorithm. A shift-up instruction is generated based on the first sampling sequence and sent to the multi-range constant current excitation source module; or a shift-down instruction is generated based on the second sampling sequence and sent to the multi-range constant current excitation source module.

17. The multi-channel acquisition method according to claim 16, characterized in that, The controller is specifically configured to calculate a first variance value based on the first sampling sequence, or to calculate a second variance value based on the second sampling sequence; If it is determined that the first variance value is less than the first variance threshold, an upgrade switching instruction is generated and sent to the multi-range constant current excitation source module; If the first variance value is greater than or equal to the first variance threshold, then maintain the current constant current level; If it is determined that the second variance value is less than the second variance threshold, a downshifting switching instruction is generated and sent to the multi-range constant current excitation source module; If the second variance value is greater than or equal to the second variance threshold, then maintain the current constant current level.

18. An airborne device, characterized in that, The multi-channel acquisition circuit for airborne systems, as described in any one of claims 1-13.

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