Filter circuit of heavy-load unmanned engineering vehicle

Abstract

The invention relates to the technical field of filter circuits, and discloses a heavy-load unmanned engineering vehicle filter circuit, which comprises an N-MOS (N-Metal Oxide Semiconductor) transistor, a signal input end, a signal output end, a signal output end, a signal output end and a signal output end, one end of the filter capacitor is connected with the source electrode of the N-MOS tube, and the other end of the filter capacitor is grounded; the input end of the ADC sampling unit is connected with the signal output end, and the ADC sampling unit samples output signals; the input end of the MCU is connected with the output end of the ADC sampling unit, the output end of the MCU is connected with the grid electrode of the N-MOS tube, and the MCU outputs driving voltage to enable the N-MOS tube to work in a variable resistance area, calculates the actual signal-to-noise ratio of an output signal, calculates an error signal according to the target signal-to-noise ratio corresponding to the type of the output signal and outputs the error signal to the ADC sampling unit. And the driving voltage output to the grid electrode of the N-MOS tube is adjusted in real time within the voltage range corresponding to the variable resistance region of the N-MOS tube until the error signal converges, and filtering output of the current input signal is completed.

Description

Technical Field

[0001] The invention relates to the technical field of filter circuits, and in particular to a filter circuit for a heavy-load unmanned engineering vehicle. Background Art

[0002] As electrification and intelligence become more and more popular in the automotive field, large-load engineering vehicles are also turning to electrification and intelligence; with the development of intelligence, unmanned driving is also beginning to be tried in large-load engineering vehicles. The working conditions of large-load engineering vehicles are complex, and various working condition analog quantities are collected through voltage sampling circuits. During the electrification process, the motor has a large working current and large electromagnetic interference, and the voltage sampling circuit is extremely susceptible to interference; at the same time, during the unmanned driving process, in order to monitor various road conditions, the voltage sampling circuit is a necessary circuit.

[0003] In order to avoid electromagnetic interference to the voltage sampling circuit, an RC circuit needs to be added to the voltage sampling circuit for filtering; compared with the traditional RC filtering circuit, the RC series filtering circuit in the large-load unmanned electric engineering vehicle requires an adjustable cutoff frequency to better filter out interference; the larger the cutoff frequency adjustment range, the higher the filtering accuracy.

[0004] Reference Figure 1 The figure shows a schematic diagram of a traditional RC filter circuit. As a common combination in electronic circuits, the traditional RC filter circuit is composed of a resistor R and a capacitor C in series or in parallel. This circuit is widely used in signal processing, filtering, and timing circuits. The interaction between resistors and capacitors enables the RC circuit to produce a specific response to the input signal, such as smoothing DC signals and filtering high-frequency noise. Among them, the RC series circuit is the most commonly used filter circuit.

[0005] In an RC series circuit, the values ​​of resistance and capacitance determine the time constant of the circuit, that is, the speed at which the circuit responds to signal changes. The larger the time constant, the slower the circuit responds to signal changes; conversely, the smaller the time constant, the faster the circuit responds to signal changes; this characteristic gives the RC series circuit a unique advantage in filtering and signal processing. The RC series circuit is also called an RC low-pass filter, and the cutoff frequency is an important parameter for the circuit to filter the input signal. For an RC series circuit, its cutoff frequency determines the highest frequency that the circuit can pass. When the frequency of the input signal is higher than the cutoff frequency, the circuit attenuates it, thereby filtering out high-frequency noise; that is, the lower the frequency, the easier it is for the signal to pass, and the higher the frequency, the less likely it is for the signal to pass.

[0006] However, the total resistance of the components in the existing RC series circuit is a fixed value and cannot be adjusted according to actual conditions, resulting in a fixed filtering frequency. When facing a large-load unmanned engineering vehicle, there are many different input signals, which require corresponding different cutoff frequencies for filtering. Therefore, the existing RC series filter circuit is not suitable for large-load unmanned engineering vehicles, has poor versatility, and cannot accurately transmit different types of input signals. Summary of the invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the filtering frequency of the RC series circuit in the prior art is fixed and the versatility is poor in large-load unmanned engineering vehicles.

[0008] In order to solve the above technical problems, the present invention provides a large-load unmanned engineering vehicle filter circuit, comprising: An N-MOS tube, whose drain is connected to the signal input terminal and whose source is connected to the signal output terminal; A filter capacitor, one end of which is connected to the source of the N-MOS tube and the other end of which is grounded; An ADC sampling unit, whose input end is connected to the signal output end, samples the output signal; The MCU, whose input end is connected to the output end of the ADC sampling unit and whose output end is connected to the gate of the N-MOS tube, outputs a driving voltage to make the N-MOS tube work in the variable resistance area, calculates the actual signal-to-noise ratio of the output signal, and calculates the error signal according to the target signal-to-noise ratio corresponding to the type of the output signal, and adjusts the driving voltage output to the gate of the N-MOS tube in real time within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube until the error signal converges, thereby completing the filtering output of the current input signal.

[0009] Preferably, the voltage input to the gate of the N-MOS tube is greater than the turn-on voltage of the N-MOS tube, and the drain-source voltage of the N-MOS tube is less than the difference between the voltage of the gate of the N-MOS tube and the turn-on voltage, so that the N-MOS tube works in the variable resistance area.

[0010] Preferably, completing the filtering output of the current input signal includes: making the voltage input to the gate of the N-MOS tube greater than the turn-on voltage of the N-MOS tube, so that the N-MOS tube operates in a constant current region, so that the filtered input signal is transmitted to the signal output end.

[0011] Preferably, after completing the filtering and outputting of the current input signal, it also includes: making the voltage input to the gate of the N-MOS tube less than the turn-on voltage of the N-MOS tube, so that the N-MOS tube operates in the pinch-off area, shutting off the signal transmission between the signal input end and the signal output end until the next input signal is input, making the N-MOS tube operate in the variable resistance area, and filtering and outputting the next input signal.

[0012] Preferably, calculating the actual signal-to-noise ratio of the output signal, calculating the error signal with the target signal-to-noise ratio corresponding to the type of the output signal, and adjusting the driving voltage output to the gate of the N-MOS tube in real time within the voltage range corresponding to the variable resistance region of the N-MOS tube, comprises: If the actual signal-to-noise ratio of the output signal is less than the target signal-to-noise ratio corresponding to the type of the output signal, the driving voltage output to the gate of the N-MOS tube is reduced within the voltage range corresponding to the variable resistance region of the N-MOS tube, thereby reducing the on-resistance of the N-MOS tube, increasing the filter cutoff frequency, and improving the actual signal-to-noise ratio of the output signal; If the actual signal-to-noise ratio of the output signal is greater than the target signal-to-noise ratio corresponding to the type of the output signal, the driving voltage output to the gate of the N-MOS tube is increased within the voltage range corresponding to the variable resistance region of the N-MOS tube, thereby increasing the on-resistance of the N-MOS tube, reducing the filter cutoff frequency, and reducing the actual signal-to-noise ratio of the output signal.

[0013] Preferably, calculating the actual signal-to-noise ratio of the output signal comprises: Perform FFT transformation on the output signal to obtain the signal spectrum; Based on the signal spectrum, the target signal band and the noise band are divided, and the corresponding band power is calculated; Based on the target signal band power and noise band power , calculate the actual signal-to-noise ratio of the output signal , expressed as: .

[0014] Preferably, the types of output signals include motor voltage signals, motor current signals, steering sensor signals, environment perception sensor signals, and vehicle communication signals.

[0015] Preferably, a temperature sensor is also included to collect the ambient temperature in real time and generate an analog signal output so as to: The ADC sampling unit obtains the analog signal and converts it into a digital signal, and then the MCU calculates the compensation voltage according to the preset temperature voltage compensation comparison table to compensate the driving voltage output to the gate of the N-MOS tube.

[0016] Preferably, the temperature sensor is coupled to the N-MOS tube via a heat sink.

[0017] Preferably, it further comprises: a body diode connected in parallel at both ends of the N-MOS tube, with an anode connected to the source of the N-MOS tube and a cathode connected to the drain of the N-MOS tube.

[0018] The above technical solution of the present invention has the following beneficial effects compared with the prior art: The present invention utilizes the variable resistance area of ​​an N-MOS tube to provide a variable resistor for the filter circuit when realizing a filter circuit for a heavy-load unmanned engineering vehicle, so as to change the filter frequency band for filtering an input signal; however, since the on-resistance of the N-MOS tube when working in the variable resistance area is not in a linear relationship with the gate voltage, it is impossible to directly control the gate voltage to achieve accurate control of the on-resistance of the N-MOS tube and the filter cutoff frequency of the circuit; on this basis, the present invention provides a method for controlling the filter frequency of the circuit by controlling the driving voltage input to the gate of the N-MOS tube.

[0019] The present invention calculates an error signal based on the actual signal-to-noise ratio of the output signal after filtering by the N-MOS tube and the filter capacitor and the target signal-to-noise ratio corresponding to the type of the output signal, and adaptively adjusts the driving voltage of the gate of the N-MOS tube within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube, thereby changing the current working resistance of the N-MOS tube working in the variable resistance area, and combining with the filter capacitor to change the filter frequency band for filtering the input signal, thereby achieving the adjustment of the circuit filter cutoff frequency, so that the abnormal signal is bypassed to the ground by the filter capacitor, the abnormal signal in the circuit is eliminated, the output signal is changed, and the error signal also changes until the error signal is adjusted to converge, and the filtering output of the current input signal is completed.

[0020] The present invention adaptively adjusts the gate voltage input to the N-MOS tube within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube through closed-loop control, changes the resistance value of the N-MOS tube to change the circuit filtering cutoff frequency, realizes millisecond-level cutoff frequency adjustment, can filter out abnormal information of different frequencies, improves the versatility of the filtering circuit based on the N-MOS tube, and further, when facing a heavy-load unmanned engineering vehicle, the corresponding cutoff frequency can be set for different input signals, thereby realizing accurate filtering of various input signals in the heavy-load unmanned engineering vehicle.

[0021] The present invention is also provided with a temperature sensor. Since temperature changes may cause the on-resistance of the N-MOS tube to drift, thus affecting the stability of the cut-off frequency, the present invention detects the temperature change of the N-MOS tube, generates a compensation voltage, and dynamically adjusts the gate voltage of the N-MOS tube to ensure the stability and accuracy of the cut-off frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a traditional RC filter circuit; Figure 2It is a schematic diagram of the transfer characteristics of the N-MOS tube; Figure 3 This is a schematic diagram of a filter circuit for a large-load unmanned engineering vehicle provided by the present invention; Figure 4 It is a schematic diagram of signal transmission of filter circuit for heavy load unmanned engineering vehicle. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0024] The cutoff frequency of the RC series circuit is the frequency at which the input signal power decreases by 3dB, also known as the -3dB frequency. At the cutoff frequency, the output voltage amplitude becomes 0.707 (1 / ) times. Figure 1 In the traditional RC series circuit shown, the capacitive reactance is The total impedance of the resistor and capacitor in series is ; Assume that the frequency is hour, The value becomes 0.707 times of ; Therefore, the cutoff frequency is expressed as ; From this we can see that in the RC filter circuit, the circuit cutoff frequency is inversely proportional to the resistance value.

[0025] Therefore, when adjusting R and C in the RC filter circuit, the cut-off frequency also changes, and the series RC circuit can filter out high-frequency signals; when realizing a large-load unmanned engineering vehicle filter circuit, the present invention uses the variable resistance area of ​​the N-MOS tube to provide a variable resistor to the filter circuit to change the filter frequency band for filtering the input signal.

[0026] Reference Figure 2 The figure shows the transfer characteristics of N-MOS tube. The transfer characteristics of N-MOS tube are divided into three regions, including pinch-off region, constant current region and variable resistance region. The present invention utilizes the variable resistance region of N-MOS tube, and uses different gate voltages to correspond to different resistance values. In the RC series circuit, N-MOS is used to replace the resistor R. According to the working requirements, different voltages are applied to the gate of N-MOS to achieve different on-resistances of N-MOS tube. Figure 2It can be seen that the on-resistance of the N-MOS tube when working in the variable resistance region is not in a linear relationship with the gate voltage. Therefore, it is impossible to directly control the gate voltage to achieve accurate control of the on-resistance of the N-MOS tube and the filter cutoff frequency of the circuit. On this basis, the present invention provides a method for controlling the filter frequency of the circuit by controlling the driving voltage input to the gate of the N-MOS tube.

[0027] Reference Figure 3 As shown, the schematic diagram of the filter circuit of the heavy load unmanned engineering vehicle of the present invention includes: An N-MOS tube, whose drain is connected to the signal input terminal and whose source is connected to the signal output terminal; A filter capacitor, one end of which is connected to the source of the N-MOS tube and the other end of which is grounded; An ADC sampling unit, whose input end is connected to the signal output end, samples the output signal; The MCU, whose input end is connected to the output end of the ADC sampling unit and whose output end is connected to the gate of the N-MOS tube, outputs a driving voltage to make the N-MOS tube work in the variable resistance area, calculates the actual signal-to-noise ratio of the output signal, and calculates the error signal according to the target signal-to-noise ratio corresponding to the type of the output signal, and adjusts the driving voltage output to the gate of the N-MOS tube in real time within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube until the error signal converges, thereby completing the filtering output of the current input signal.

[0028] In this embodiment, the voltage input to the gate of the N-MOS tube is greater than the turn-on voltage of the N-MOS tube, and the drain-source voltage of the N-MOS tube is less than the difference between the voltage of the gate of the N-MOS tube and the turn-on voltage, so that the N-MOS tube works in the variable resistance area.

[0029] In this embodiment, the filtering output of the current input signal is completed, including: making the voltage input to the gate of the N-MOS tube greater than the turn-on voltage of the N-MOS tube, so that the N-MOS tube operates in the constant current region, so that the filtered input signal is transmitted to the signal output end.

[0030] In this embodiment, after completing the filtering and outputting of the current input signal, it also includes: making the voltage input to the gate of the N-MOS tube less than the turn-on voltage of the N-MOS tube, so that the N-MOS tube operates in the pinch-off area, shutting off the signal transmission between the signal input end and the signal output end until the next input signal is input, making the N-MOS tube operate in the variable resistance area, and filtering and outputting the next input signal.

[0031] The actual signal-to-noise ratio of the output signal is calculated, and an error signal is calculated based on a target signal-to-noise ratio corresponding to the type of the output signal, and a driving voltage output to the gate of the N-MOS tube is adjusted in real time within a voltage range corresponding to a variable resistance region of the N-MOS tube, including: If the actual signal-to-noise ratio of the output signal is less than the target signal-to-noise ratio corresponding to the type of the output signal, the driving voltage output to the gate of the N-MOS tube is reduced within the voltage range corresponding to the variable resistance region of the N-MOS tube, thereby reducing the on-resistance of the N-MOS tube, increasing the filter cutoff frequency, and improving the actual signal-to-noise ratio of the output signal; If the actual signal-to-noise ratio of the output signal is greater than the target signal-to-noise ratio corresponding to the type of the output signal, the driving voltage output to the gate of the N-MOS tube is increased within the voltage range corresponding to the variable resistance region of the N-MOS tube, thereby increasing the on-resistance of the N-MOS tube, reducing the filter cutoff frequency, and reducing the actual signal-to-noise ratio of the output signal.

[0032] The present invention calculates an error signal based on the actual signal-to-noise ratio of the output signal after filtering by the N-MOS tube and the filter capacitor and the target signal-to-noise ratio corresponding to the type of the output signal, and adaptively adjusts the driving voltage of the gate of the N-MOS tube within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube, thereby changing the current working resistance of the N-MOS tube working in the variable resistance area, and combining with the filter capacitor to change the filter frequency band for filtering the input signal, thereby achieving the adjustment of the circuit filter cutoff frequency, so that the abnormal signal is bypassed to the ground by the filter capacitor, the abnormal signal in the circuit is eliminated, the output signal is changed, and the error signal also changes until the error signal is adjusted to converge, and the filtering output of the current input signal is completed.

[0033] In this embodiment, the types of output signals include motor voltage signals, motor current signals, steering sensor signals, environment perception sensor signals, and vehicle communication signals.

[0034] For different types of output signals, the method for calculating the actual signal-to-noise ratio is the same. Calculating the actual signal-to-noise ratio of the output signal includes: Perform FFT transformation on the output signal to obtain the signal spectrum; Based on the signal spectrum, the target signal band and the noise band are divided, and the corresponding band power is calculated; Based on the target signal band power and noise band power , calculate the actual signal-to-noise ratio of the output signal , expressed as: .

[0035] The present invention adaptively adjusts the gate voltage input to the N-MOS tube within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube through closed-loop control, changes the resistance value of the N-MOS tube to change the circuit filtering cutoff frequency, realizes millisecond-level cutoff frequency adjustment, can filter out abnormal information of different frequencies, improves the versatility of the filtering circuit based on the N-MOS tube, and further, when facing a heavy-load unmanned engineering vehicle, the corresponding cutoff frequency can be set for different input signals, thereby realizing accurate filtering of various input signals in the heavy-load unmanned engineering vehicle.

[0036] Specifically, this embodiment further includes a body diode connected in parallel at both ends of the N-MOS tube, with its anode connected to the source of the N-MOS tube and its cathode connected to the drain of the N-MOS tube. The body diode of the N-MOS tube can clamp the output signal to ensure that the output signal is 0.7V higher than the input signal, making the output signal safer.

[0037] Based on the above embodiments, the embodiments of the present invention also include a temperature sensor, which collects the ambient temperature in real time and generates an analog signal output, so that the ADC sampling unit obtains the analog signal and converts it into a digital signal, and then the MCU calculates and obtains the compensation voltage according to a preset temperature voltage compensation comparison table to compensate the driving voltage output to the gate of the N-MOS tube.

[0038] In order to enable the temperature sensor to more accurately sense the temperature change of the N-MOS tube, this embodiment couples the temperature sensor and the N-MOS tube through a heat sink to achieve more accurate temperature compensation.

[0039] The present invention is also provided with a temperature sensor. Since temperature changes may cause the on-resistance of the N-MOS tube to drift, thus affecting the stability of the cut-off frequency, the present invention detects the temperature change of the N-MOS tube, generates a compensation voltage, and dynamically adjusts the gate voltage of the N-MOS tube to ensure the stability and accuracy of the cut-off frequency.

[0040] Reference Figure 4 As shown, it is a schematic diagram of signal transmission of the filter circuit of a large-load unmanned engineering vehicle; is the input signal, is the output signal, Z is the N-MOS tube, K is the internal diode of the N-MOS tube, C is the filter capacitor, and the sampling circuit is the sampled output signal , the control unit samples the input signal and output signal, outputs the control signal to the N-MOS tube, and the input signal Connect to the drain of N-MOS tube Z and the cathode of diode K in the N-MOS tube, and connect to the control unit at the same time. The source of N-MOS is connected to the anode of diode K in the N-MOS body, and connected to one end of the filter capacitor and the output signal. , and connect one end of the sampling circuit at the same time, the other end of the sampling circuit is connected to the control system, the other end of the filter capacitor is grounded, and one end of the control system is connected to the gate of the N-MOS tube Z.

[0041] Specifically, The input signal may be interfered with and mixed with various abnormal signals. For the output signal, it is expected to collect the real signal; the control unit samples the input signal and the output signal respectively, and outputs different control voltages to the gate of the N-MOS according to the needs of the system. According to the transfer characteristics of the N-MOS, the control voltage makes the N-MOS work in the variable resistance area. At this time, the N-MOS becomes a resistor, and different resistance values ​​are combined with the filter capacitor C for filtering. At this time, the cut-off frequency also changes, filtering out the interference signal of the input signal, and the normal signal is transmitted to the output signal At the same time, due to the internal diode of N-MOS, the input signal is clamped. If the output signal is abnormally interfered, the internal diode of N-MOS will ensure that the output signal is 0.7V higher than the input signal, thus protecting the input signal.

[0042] In summary, in the actual application of large-load unmanned electric engineering vehicles, the voltage sampling circuit is very susceptible to interference. This embodiment uses the variable resistance area in the N-MOS transfer characteristic to convert it into the required resistance according to the needs of the system. The resistance and capacitance determine the cut-off frequency, thereby achieving adjustable cut-off frequency and effectively filtering out interference. In the variable resistance area in the N-MOS transfer characteristic, the variable resistance can range from tens to hundreds of K. Compared with traditional circuits, the cut-off frequency varies greatly. At the same time, the adjustable resistance accuracy of N-MOS is large, and a few ohms or even smaller can be achieved. The cut-off frequency can be accurately adjusted. At the same time, the diode in the N-MOS outputs the signal to protect the input signal.

[0043] The present invention calculates an error signal based on the actual signal-to-noise ratio of the output signal after filtering by the N-MOS tube and the filter capacitor and the target signal-to-noise ratio corresponding to the type of the output signal, and adaptively adjusts the driving voltage of the gate of the N-MOS tube within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube, thereby changing the current working resistance of the N-MOS tube working in the variable resistance area, and combining with the filter capacitor to change the filter frequency band for filtering the input signal, thereby achieving the adjustment of the circuit filter cutoff frequency, so that the abnormal signal is bypassed to the ground by the filter capacitor, the abnormal signal in the circuit is eliminated, the output signal is changed, and the error signal also changes until the error signal is adjusted to converge, and the filtering output of the current input signal is completed. The present invention adaptively adjusts the gate voltage input to the N-MOS tube within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube through closed-loop control, changes the resistance value of the N-MOS tube to change the circuit filtering cutoff frequency, realizes millisecond-level cutoff frequency adjustment, can filter out abnormal information of different frequencies, improves the versatility of the filtering circuit based on the N-MOS tube, and further, when facing a heavy-load unmanned engineering vehicle, the corresponding cutoff frequency can be set for different input signals, thereby realizing accurate filtering of various input signals in the heavy-load unmanned engineering vehicle.

[0044] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0045] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0046] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0047] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0048] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A filter circuit for a large load unmanned engineering vehicle, characterized in that: include: An N-MOS tube, whose drain is connected to the signal input terminal and whose source is connected to the signal output terminal; A filter capacitor, one end of which is connected to the source of the N-MOS tube and the other end of which is grounded; An ADC sampling unit, whose input end is connected to the signal output end, samples the output signal; The MCU, whose input end is connected to the output end of the ADC sampling unit and whose output end is connected to the gate of the N-MOS tube, outputs a driving voltage to make the N-MOS tube work in the variable resistance area, calculates the actual signal-to-noise ratio of the output signal, and calculates the error signal with the target signal-to-noise ratio corresponding to the type of the output signal, and adjusts the driving voltage output to the gate of the N-MOS tube in real time within the voltage range corresponding to the variable resistance area of ​​the N-MOS tube until the error signal converges, thereby completing the filtering output of the current input signal.

2. The heavy-load unmanned engineering vehicle filter circuit according to claim 1 is characterized in that: The voltage input to the gate of the N-MOS tube is made greater than the turn-on voltage of the N-MOS tube, and the drain-source voltage of the N-MOS tube is made smaller than the difference between the voltage of the gate of the N-MOS tube and the turn-on voltage, so that the N-MOS tube works in the variable resistance area.

3. The heavy-load unmanned engineering vehicle filter circuit according to claim 1 is characterized in that: The filtering output of the current input signal is completed, including: making the voltage input to the gate of the N-MOS tube greater than the turn-on voltage of the N-MOS tube, so that the N-MOS tube works in the constant current region, so that the filtered input signal is transmitted to the signal output end.

4. The heavy-load unmanned engineering vehicle filter circuit according to claim 1, characterized in that: After completing the filtering and outputting of the current input signal, it also includes: making the voltage input to the gate of the N-MOS tube less than the turn-on voltage of the N-MOS tube, so that the N-MOS tube works in the pinch-off area, shutting off the signal transmission between the signal input end and the signal output end until the next input signal is input, making the N-MOS tube work in the variable resistance area, and filtering and outputting the next input signal.

5. The heavy-load unmanned engineering vehicle filter circuit according to claim 1, characterized in that: Calculate the actual signal-to-noise ratio of the output signal, calculate the error signal with the target signal-to-noise ratio corresponding to the type of the output signal, and adjust the drive voltage output to the gate of the N-MOS tube in real time within the voltage range corresponding to the variable resistance region of the N-MOS tube, including: If the actual signal-to-noise ratio of the output signal is less than the target signal-to-noise ratio corresponding to the type of the output signal, the driving voltage output to the gate of the N-MOS tube is reduced within the voltage range corresponding to the variable resistance region of the N-MOS tube, thereby reducing the on-resistance of the N-MOS tube, increasing the filter cutoff frequency, and improving the actual signal-to-noise ratio of the output signal; If the actual signal-to-noise ratio of the output signal is greater than the target signal-to-noise ratio corresponding to the type of the output signal, the driving voltage output to the gate of the N-MOS tube is increased within the voltage range corresponding to the variable resistance region of the N-MOS tube, thereby increasing the on-resistance of the N-MOS tube, reducing the filter cutoff frequency, and reducing the actual signal-to-noise ratio of the output signal.

6. The heavy-load unmanned engineering vehicle filter circuit according to claim 1, characterized in that: Calculate the actual signal-to-noise ratio of the output signal, including: Perform FFT transformation on the output signal to obtain the signal spectrum; Based on the signal spectrum, the target signal band and the noise band are divided, and the corresponding band power is calculated; Based on the target signal band power and noise band power , calculate the actual signal-to-noise ratio of the output signal , expressed as: .

7. The heavy-load unmanned engineering vehicle filter circuit according to claim 1, characterized in that: The types of output signals include motor voltage signals, motor current signals, steering sensor signals, environmental perception sensor signals, and vehicle communication signals.

8. The heavy-load unmanned engineering vehicle filter circuit according to claim 1, characterized in that: It also includes a temperature sensor to collect ambient temperature in real time and generate analog signal output to: The ADC sampling unit obtains the analog signal and converts it into a digital signal, and then the MCU calculates the compensation voltage according to the preset temperature voltage compensation comparison table to compensate the driving voltage output to the gate of the N-MOS tube.

9. The heavy-load unmanned engineering vehicle filter circuit according to claim 8, characterized in that: The temperature sensor is coupled to the N-MOS tube via a heat sink.

10. The heavy-load unmanned engineering vehicle filter circuit according to claim 1, characterized in that: Also includes: A body diode is connected in parallel to both ends of the N-MOS tube, with an anode connected to the source of the N-MOS tube and a cathode connected to the drain of the N-MOS tube.

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