A filtering circuit for a large-load driverless engineering vehicle

Abstract

The present invention relates to the technical field of filter circuits, and discloses a filter circuit for a large-load driverless engineering vehicle, including: an N-MOS transistor, whose drain is connected to the signal input end and whose source is connected to the signal output end; a filter capacitor, one end of which is connected to the source of the N-MOS transistor and the other end of which is grounded; an ADC sampling unit, whose input end is connected to the signal output end to sample the output signal; an 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 transistor. After outputting a driving voltage to make the N-MOS transistor operate in the variable resistance region, it calculates the actual signal-to-noise ratio of the output signal, calculates an error signal with the target signal-to-noise ratio corresponding to the type of the output signal, and adjusts in real time the driving voltage output to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor until the error signal converges, so as to complete the filtered output of the current input signal.

Description

Technical Field

[0001] The present invention relates to the technical field of filter circuits, and particularly to a filter circuit for large-load driverless engineering vehicles. Background Art

[0002] With the increasing popularity of electrification and intelligentization in the automotive field, large-load engineering vehicles have also started to turn towards electrification and intelligentization; with the development of intelligentization, driverless technology has also begun to be tried in large-load engineering vehicles. The working conditions of large-load engineering vehicles are complex, and various analog quantities of working conditions are collected through a voltage sampling circuit. During the electrification process, the working current of the motor is large, and the electromagnetic interference is strong, so the voltage sampling circuit is extremely vulnerable to interference; at the same time, during the driverless process, the voltage sampling circuit is a necessary circuit for monitoring various road conditions.

[0003] 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 filter circuit, the RC series filter circuit in large-load driverless electric engineering vehicles requires an adjustable cut-off frequency to better filter out interference; the larger the adjustment range of its cut-off frequency, the higher the filtering accuracy.

[0004] Refer to Figure 1 As shown, it is a schematic diagram of a traditional RC filter circuit; the traditional RC filter circuit, as a common combination in electronic circuits, is composed of a resistor R and a capacitor C connected in series or in parallel. This circuit has a wide range of applications in signal processing, filtering, and timing circuits; the interaction between the resistor and the capacitor enables the RC circuit to produce a specific response to the input signal, such as smoothing DC signals, filtering out high-frequency noise, etc. Among them, the RC series circuit is the most commonly used filter circuit.

[0005] In an RC series circuit, the values of the resistor and the capacitor determine the time constant of the circuit, that is, the response speed of the circuit to signal changes. The larger the time constant, the slower the response of the circuit to signal changes; conversely, the smaller the time constant, the faster the response of the circuit to signal changes; this characteristic makes the RC series circuit have unique advantages in filtering and signal processing. The RC series circuit is also called an RC low-pass filter, and the cut-off frequency is an important parameter for the circuit to filter the input signal. For an RC series circuit, its cut-off frequency determines the highest frequency that the circuit can pass. When the frequency of the input signal is higher than the cut-off 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 more difficult it is for the signal to pass.

[0006] However, in the existing RC series circuit, the total resistance value composed of each component is a fixed value and cannot be adjusted according to the actual situation, resulting in a fixed filtering frequency. When facing large-load driverless engineering vehicles, there are various different input signals, and corresponding different cut-off frequencies are required for filtering. Therefore, the existing RC series filtering circuit is not applicable to large-load driverless 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 in large-load driverless engineering vehicles is poor.

[0008] To solve the above technical problem, the present invention provides a filtering circuit for large-load driverless engineering vehicles, including:

[0009] An N-MOS transistor, whose drain is connected to the signal input terminal and whose source is connected to the signal output terminal;

[0010] A filtering capacitor, one end of which is connected to the source of the N-MOS transistor and the other end of which is grounded;

[0011] An ADC sampling unit, whose input terminal is connected to the signal output terminal to sample the output signal;

[0012] An MCU, whose input terminal is connected to the output terminal of the ADC sampling unit, and whose output terminal is connected to the gate of the N-MOS transistor. After outputting a driving voltage to make the N-MOS transistor work in the variable resistance region, it calculates the actual signal-to-noise ratio of the output signal, calculates an 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 transistor in real time within the voltage range corresponding to the variable resistance region of the N-MOS transistor until the error signal converges, and completes the filtered output of the current input signal.

[0013] Preferably, the voltage input to the gate of the N-MOS transistor is greater than the turn-on voltage of the N-MOS transistor, and the drain-source voltage of the N-MOS transistor is less than the difference between the voltage of the gate of the N-MOS transistor and the turn-on voltage, so that the N-MOS transistor works in the variable resistance region.

[0014] Preferably, completing the filtered output of the current input signal includes: making the voltage input to the gate of the N-MOS transistor greater than the turn-on voltage of the N-MOS transistor, so that the N-MOS transistor works in the constant current region, and the filtered input signal is transmitted to the signal output terminal.

[0015] Preferably, after completing the filtered output of the current input signal, it further includes: making the voltage input to the gate of the N-MOS transistor less than the turn-on voltage of the N-MOS transistor, so that the N-MOS transistor operates in the pinch-off region, turning off the signal transmission between the signal input terminal and the signal output terminal until the next input signal is input, and making the N-MOS transistor operate in the variable resistance region to perform filtered output on the next input signal.

[0016] Preferably, 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 driving voltage output to the gate of the N-MOS transistor in real time within the voltage range corresponding to the variable resistance region of the N-MOS transistor, including:

[0017] 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, then reduce the driving voltage output to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor, thereby reducing the on-resistance of the N-MOS transistor, increasing the filter cut-off frequency, and improving the actual signal-to-noise ratio of the output signal;

[0018] 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, then increase the driving voltage output to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor, thereby increasing the on-resistance of the N-MOS transistor, reducing the filter cut-off frequency, and reducing the actual signal-to-noise ratio of the output signal.

[0019] Preferably, calculating the actual signal-to-noise ratio of the output signal includes:

[0020] Performing FFT transformation on the output signal to obtain the signal spectrum;

[0021] Based on the signal spectrum, divide the target signal frequency band and the noise frequency band, and calculate the corresponding band powers;

[0022] Based on the target signal band power and the noise band power , calculate the actual signal-to-noise ratio of the output signal , expressed as: .

[0023] Preferably, the types of output signals include motor voltage signals, motor current signals, steering sensor signals, environmental perception sensor signals, and vehicle-mounted communication signals.

[0024] Preferably, it further includes a temperature sensor to collect the ambient temperature in real time and generate an analog signal output for:

[0025] After the ADC sampling unit acquires the analog signal and converts it into a digital signal, the MCU calculates and obtains the compensation voltage according to the preset temperature-voltage compensation comparison table, and compensates the driving voltage output to the gate of the N-MOS transistor.

[0026] Preferably, the temperature sensor and the N-MOS transistor are coupled through a heat sink.

[0027] Preferably, it further includes: a body diode, connected in parallel across the two ends of the N-MOS transistor, with its anode connected to the source of the N-MOS transistor and its cathode connected to the drain of the N-MOS transistor.

[0028] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0029] When implementing the filtering circuit of a large-load driverless engineering vehicle, the present invention uses the variable resistance region of the N-MOS transistor to provide a variable resistance for the filtering circuit to change the filtering frequency band for filtering the input signal; however, since the on-resistance of the N-MOS transistor when working in the variable resistance region is not linearly related to the gate voltage, therefore, it is impossible to directly control the gate voltage to accurately control the on-resistance of the N-MOS transistor and the filtering cut-off frequency of the circuit; on this basis, the present invention provides a method for controlling the filtering frequency of the circuit by controlling the driving voltage input to the gate of the N-MOS transistor.

[0030] Based on the actual signal-to-noise ratio of the output signal after filtering by the N-MOS transistor and the filter capacitor and the target signal-to-noise ratio corresponding to the type of the output signal, the present invention calculates an error signal, adaptively adjusts the driving voltage input to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor, thereby changing the current working resistance value of the N-MOS transistor working in the variable resistance region, combined with the filter capacitor, changing the filtering frequency band for filtering the input signal, so as to realize the adjustment of the filtering cut-off frequency of the circuit, enabling abnormal signals to be bypassed to the ground by the filter capacitor, eliminating the abnormal signals in the circuit, changing the output signal, and the error signal also changes until the error signal converges, completing the filtering output of the current input signal.

[0031] The present invention adaptively adjusts the gate voltage input to the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor through closed-loop control, changes the resistance value of the N-MOS transistor to change the filtering cut-off frequency of the circuit, realizes the cut-off frequency adjustment in milliseconds, can filter out abnormal information of different frequencies, improves the versatility of the filtering circuit based on the N-MOS transistor, and further, when facing a large-load driverless engineering vehicle, can set corresponding cut-off frequencies for different input signals to achieve precise filtering of various input signals in the large-load driverless engineering vehicle.

[0032] The present invention is also provided with a temperature sensor. Since temperature changes can cause the on-resistance of the N-MOS transistor to drift, affecting the stability of the cut-off frequency, the present invention detects the temperature change of the N-MOS transistor, generates a compensation voltage, and dynamically adjusts the gate voltage of the N-MOS transistor to ensure the stable and accurate cut-off frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the content of the present invention easier to be clearly understood, the following further details the present invention according to specific embodiments of the present invention in conjunction with the drawings, wherein:

[0034] Figure 1 is a schematic diagram of a traditional RC filter circuit;

[0035] Figure 2 is a schematic diagram of the transfer characteristics of an N-MOS transistor;

[0036] Figure 3 is a schematic diagram of the filter circuit of a large-load driverless engineering vehicle provided by the present invention;

[0037] Figure 4 is a schematic diagram of signal transmission of the filter circuit of a large-load driverless engineering vehicle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The following further describes the present invention in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments cited do not limit the present invention.

[0039] The cut-off frequency of an RC series circuit is the frequency at which the input signal power is reduced by 3 dB, also known as the -3 dB frequency. At the cut-off frequency, the output voltage amplitude becomes 0.707 (1 / ) times the original. In the traditional RC series circuit as shown in Figure 1 , the capacitive reactance is , and the total impedance of the series connection of the resistor and the capacitor is ; assuming that at a frequency of , the value becomes 0.707 times that of , expressed as ; therefore, the cut-off frequency is expressed as ; it can be seen therefrom that in an RC filter circuit, the circuit cut-off frequency is inversely proportional to the resistance value.

[0040] Therefore, when adjusting R and C in the RC filter circuit, the cut-off frequency also changes accordingly, and the series RC circuit can filter out high-frequency signals; when implementing the filter circuit of a large-load driverless engineering vehicle, the present invention uses the variable resistance region of the N-MOS transistor to provide a variable resistance for the filter circuit to change the filtering frequency band for filtering the input signal.

[0041] Referring to Figure 2 As shown, it is a schematic diagram of the transfer characteristics of an N-MOS transistor; the transfer characteristics of an N-MOS transistor are divided into three regions, including the pinch-off region, the constant-current region, and the variable-resistance region; the present invention utilizes the variable-resistance region of the N-MOS transistor, through different resistance values corresponding to different gate voltages, in an RC series circuit, replaces the resistor R with an N-MOS, and applies different voltages to the gate of the N-MOS according to the working requirements to achieve different on-resistances of the N-MOS transistor. From Figure 2 it can be seen that when the N-MOS transistor operates in the variable-resistance region, the on-resistance and the gate voltage are not linearly related. Therefore, it is impossible to directly control the on-resistance of the N-MOS transistor and the accurate control of the filter cut-off frequency of the circuit by controlling the gate voltage; on this basis, the present invention provides a method for controlling the filter frequency of a circuit by controlling the drive voltage input to the gate of the N-MOS transistor.

[0042] Referring to Figure 3 As shown, it is a schematic diagram of the filter circuit of a large-load driverless engineering vehicle according to the present invention. The specific circuit includes:

[0043] An N-MOS transistor, whose drain is connected to the signal input terminal and whose source is connected to the signal output terminal;

[0044] A filter capacitor, one end of which is connected to the source of the N-MOS transistor and the other end is grounded;

[0045] An ADC sampling unit, whose input terminal is connected to the signal output terminal to sample the output signal;

[0046] An MCU, whose input terminal is connected to the output terminal of the ADC sampling unit, and whose output terminal is connected to the gate of the N-MOS transistor. After outputting a drive voltage to make the N-MOS transistor operate in the variable-resistance region, it calculates the actual signal-to-noise ratio of the output signal, calculates an error signal with the target signal-to-noise ratio corresponding to the type of the output signal, and adjusts the drive voltage output to the gate of the N-MOS transistor in real time within the voltage range corresponding to the variable-resistance region of the N-MOS transistor until the error signal converges, and completes the filtered output of the current input signal.

[0047] In this embodiment, the voltage input to the gate of the N-MOS transistor is made greater than the turn-on voltage of the N-MOS transistor, and the drain-source voltage of the N-MOS transistor is less than the difference between the gate voltage and the turn-on voltage of the N-MOS transistor, so that the N-MOS transistor operates in the variable-resistance region.

[0048] In this embodiment, completing the filtered output of the current input signal includes: making the voltage input to the gate of the N-MOS transistor greater than the turn-on voltage of the N-MOS transistor, so that the N-MOS transistor operates in the constant-current region, and the filtered input signal is transmitted to the signal output terminal.

[0049] In this embodiment, after filtering and outputting the current input signal, the following steps are further included: making the voltage input to the gate of the N-MOS transistor less than the turn-on voltage of the N-MOS transistor, so that the N-MOS transistor operates in the pinch-off region, turning off the signal transmission between the signal input terminal and the signal output terminal until the next input signal is input, making the N-MOS transistor operate in the variable resistance region, and filtering and outputting the next input signal.

[0050] Among them, calculating the actual signal-to-noise ratio of the output signal, calculating an 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 transistor in real time within the voltage range corresponding to the variable resistance region of the N-MOS transistor includes:

[0051] 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, then within the voltage range corresponding to the variable resistance region of the N-MOS transistor, reduce the driving voltage output to the gate of the N-MOS transistor, thereby reducing the on-resistance of the N-MOS transistor, increasing the filter cut-off frequency, and improving the actual signal-to-noise ratio of the output signal;

[0052] 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, then within the voltage range corresponding to the variable resistance region of the N-MOS transistor, increase the driving voltage output to the gate of the N-MOS transistor, thereby increasing the on-resistance of the N-MOS transistor, reducing the filter cut-off frequency, and reducing the actual signal-to-noise ratio of the output signal.

[0053] Based on the actual signal-to-noise ratio of the output signal after filtering by the N-MOS transistor and the filter capacitor and the target signal-to-noise ratio corresponding to the type of the output signal, the present invention calculates an error signal, adaptively adjusts the driving voltage input to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor, thereby changing the current operating resistance value of the N-MOS transistor operating in the variable resistance region, combining with the filter capacitor, changing the filter frequency band for filtering the input signal, thereby realizing the adjustment of the filter cut-off frequency of the circuit, making the abnormal signal bypassed to the ground by the filter capacitor, eliminating the abnormal signal in the circuit, changing the output signal, and the error signal also changes until the error signal converges, completing the filtering and output of the current input signal.

[0054] In this embodiment, the types of output signals include motor voltage signals, motor current signals, steering sensor signals, environmental perception sensor signals, and vehicle-mounted communication signals.

[0055] For different types of output signals, the method of calculating the actual signal-to-noise ratio is the same. Calculating the actual signal-to-noise ratio of the output signal includes:

[0056] Perform FFT transformation on the output signal to obtain the signal spectrum;

[0057] Based on the signal spectrum, divide the target signal frequency band and the noise frequency band, and calculate the corresponding band power;

[0058] Based on the target signal band power and the noise band power , calculate the actual signal-to-noise ratio of the output signal , expressed as: .

[0059] In the present invention, through closed-loop control, the gate voltage input to the N-MOS transistor is adaptively adjusted within the voltage range corresponding to the variable resistance region of the N-MOS transistor, and the resistance value of the N-MOS transistor is changed to change the circuit filter cut-off frequency, realizing cut-off frequency adjustment at the millisecond level, capable of filtering abnormal information of different frequencies, improving the versatility of the filter circuit based on the N-MOS transistor. Furthermore, when facing large-load driverless engineering vehicles, corresponding cut-off frequencies can be set for different input signals to achieve precise filtering of various input signals in large-load driverless engineering vehicles.

[0060] Specifically, this embodiment further includes a body diode, which is connected in parallel across the two ends of the N-MOS transistor, with its anode connected to the source electrode of the N-MOS transistor and its cathode connected to the drain electrode of the N-MOS transistor. The body diode of the N-MOS transistor can clamp the output signal to ensure that the output signal is 0.7V higher than the input signal, making the output signal safer.

[0061] Based on the above embodiment, in the embodiment of the present invention, a temperature sensor is further included, which real-time collects the ambient temperature, generates an analog signal output, so that the ADC sampling unit can obtain the analog signal, convert it into a digital signal, and then enable the MCU to calculate and obtain a compensation voltage according to a preset temperature-voltage compensation look-up table to compensate the drive voltage output to the gate of the N-MOS transistor.

[0062] Among them, in order to enable the temperature sensor to more accurately sense the temperature change of the N-MOS transistor, in this embodiment, the temperature sensor and the N-MOS transistor are coupled through a heat sink to achieve more accurate temperature compensation.

[0063] The present invention is also provided with a temperature sensor. Since temperature changes will cause the on-resistance of the N-MOS transistor to drift, affecting the stability of the cut-off frequency, the present invention detects the temperature change of the N-MOS transistor, generates a compensation voltage, and dynamically adjusts the gate voltage of the N-MOS transistor to ensure the stable and accurate cut-off frequency.

[0064] Refer to Figure 4 shown, which is a signal transmission schematic diagram of the filter circuit for large-load driverless engineering vehicles; among them, is the input signal, Let the output signal be \(Y\), the \(N\)-MOS transistor be \(Z\), the body diode of the \(N\)-MOS transistor be \(K\), the filter capacitor be \(C\), and the sampling circuit samples the output signal. , The control unit samples the input signal and the output signal, and outputs a control signal to the \(N\)-MOS transistor. The input signal is connected to the drain of the \(N\)-MOS transistor \(Z\) and the cathode of the body diode \(K\) of the \(N\)-MOS transistor, and is also connected to the control unit. The source of the \(N\)-MOS is connected to the anode of the body diode \(K\) of the \(N\)-MOS, and is also connected to one end of the filter capacitor and the output signal. , and is also connected to one end of the sampling circuit. The other end of the sampling circuit is connected to the control system. The other end of the filter capacitor is grounded. One end of the control system is connected to the gate of the \(N\)-MOS transistor \(Z\).

[0065] Specifically, Let the input signal be \(X\). The input signal may be interfered with and contaminated with various abnormal signals. Let the output signal be \(Y\). It is expected to collect a 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 operate in the variable resistance region. 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 signals of the input signal, and the normal signal is transmitted to the output signal. ; At the same time, due to the body diode of the \(N\)-MOS, the input signal is clamped. If the output signal is abnormally interfered, the body diode of the \(N\)-MOS will ensure that the output signal is higher than the input signal by \(0.7V\), protecting the input signal.

[0066] In summary, in the actual application process of large-load driverless electric engineering vehicles, the voltage sampling circuit is extremely vulnerable to interference. In this embodiment, the variable resistance region in the transfer characteristics of the \(N\)-MOS is utilized. According to the needs of the system, it is converted into the required resistance. The resistance and capacitance determine the cut-off frequency, thereby realizing adjustable cut-off frequency and effectively filtering out interference. In the variable resistance region of the transfer characteristics of the \(N\)-MOS, the variable resistance can range from dozens to hundreds of \(K\) ohms. Compared with traditional circuits, the change range of the cut-off frequency is large. At the same time, the adjustable resistance accuracy of the \(N\)-MOS is large, and resistances of a few ohms or even smaller can be achieved, so the cut-off frequency can be accurately adjusted. At the same time, the body diode of the \(N\)-MOS outputs a signal to protect the input signal.

[0067] Based on the actual signal-to-noise ratio of the output signal after filtering by an N-MOS transistor and a filter capacitor and the target signal-to-noise ratio corresponding to the type of the output signal, an error signal is calculated. By adaptively adjusting the driving voltage of the gate of the input N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor, the current operating resistance value of the N-MOS transistor operating in the variable resistance region is changed. Combined with the filter capacitor, the filter frequency band for filtering the input signal is changed, thereby realizing the adjustment of the filter cut-off frequency of the circuit, enabling abnormal signals to be bypassed to ground by the filter capacitor, eliminating the abnormal signals in the circuit, changing the output signal, and the error signal also changes until the error signal converges, completing the filtered output of the current input signal. The present invention adaptively adjusts the gate voltage input to the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor through closed-loop control, changes the resistance value of the N-MOS transistor to change the filter cut-off frequency of the circuit, realizes the cut-off frequency adjustment at the millisecond level, can filter out abnormal information of different frequencies, improves the versatility of the filter circuit based on the N-MOS transistor, and thus when facing large-load unmanned engineering vehicles, corresponding cut-off frequencies can be set for different input signals to achieve precise filtering of various input signals in large-load unmanned engineering vehicles.

[0068] Those skilled in the art should understand that the embodiments of the present application may be provided as a method, a system, or a computer program product. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application may take 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 code.

[0069] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0070] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more of the processes and / or blocks Figure 1 one or more processes and / or blocks Figure 1 specified in the function of the block or blocks.

[0071] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes and / or blocks Figure 1 one or more processes and / or blocks Figure 1 specified in the function of the block or blocks.

[0072] Obviously, the above embodiments are only examples for clear illustration and are not limitations on the implementation. For those of ordinary skill 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 enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A filtering circuit for a large-load driverless engineering vehicle, characterized in that, Including: An N-MOS transistor, whose drain is connected to the signal input terminal and whose source is connected to the signal output terminal; A filtering capacitor, one end of which is connected to the source of the N-MOS transistor and the other end of which is grounded; An ADC sampling unit, whose input terminal is connected to the signal output terminal to sample the output signal; An MCU, whose input terminal is connected to the output terminal of the ADC sampling unit, and whose output terminal is connected to the gate of the N-MOS transistor. After outputting a driving voltage to make the N-MOS transistor operate in the variable resistance region, it calculates the actual signal-to-noise ratio of the output signal, calculates an error signal with the target signal-to-noise ratio corresponding to the type of the output signal, and adjusts in real time the driving voltage output to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor until the error signal converges, thereby completing the filtered output of the current input signal; Among them, calculating the actual signal-to-noise ratio of the output signal, calculating an error signal with the target signal-to-noise ratio corresponding to the type of the output signal, and adjusting in real time the driving voltage output to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor includes: 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, then reduce the driving voltage output to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor, thereby reducing the on-resistance of the N-MOS transistor, increasing the filtering cut-off frequency, and increasing 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, then increase the driving voltage output to the gate of the N-MOS transistor within the voltage range corresponding to the variable resistance region of the N-MOS transistor, thereby increasing the on-resistance of the N-MOS transistor, reducing the filtering cut-off frequency, and reducing the actual signal-to-noise ratio of the output signal.

2. The filter circuit of the large-load driverless engineering vehicle according to claim 1, wherein Make the voltage input to the gate of the N-MOS transistor greater than the turn-on voltage of the N-MOS transistor, and the drain-source voltage of the N-MOS transistor is less than the difference between the voltage of the gate of the N-MOS transistor and the turn-on voltage, so that the N-MOS transistor operates in the variable resistance region.

3. The filter circuit of the large-load driverless engineering vehicle according to claim 1, characterized in that Completing the filtered output of the current input signal includes: making the voltage input to the gate of the N-MOS transistor greater than the turn-on voltage of the N-MOS transistor, so that the N-MOS transistor operates in the constant current region, and enabling the filtered input signal to be transmitted to the signal output terminal.

4. The filter circuit of the large-load driverless engineering vehicle according to claim 1, wherein, After completing the filtered output of the current input signal, it further includes: making the voltage input to the gate of the N-MOS transistor less than the turn-on voltage of the N-MOS transistor, so that the N-MOS transistor operates in the pinch-off region, turning off the signal transmission between the signal input terminal and the signal output terminal until the next input signal is input, making the N-MOS transistor operate in the variable resistance region, and performing filtered output on the next input signal.

5. The filtering circuit of the large-load driverless engineering vehicle according to claim 1, wherein Calculating the actual signal-to-noise ratio of the output signal includes: Performing FFT transformation on the output signal to obtain the signal spectrum; Based on the signal spectrum, dividing the target signal frequency band and the noise frequency band, and calculating the corresponding band powers; Based on the target signal band power and the noise band power , calculate the actual signal-to-noise ratio of the output signal , expressed as: .

6. The filter circuit of the large-load driverless engineering vehicle according to claim 1, wherein, The types of output signals include motor voltage signals, motor current signals, steering sensor signals, environment perception sensor signals, vehicle-mounted communication signals.

7. The filter circuit of the large-load driverless engineering vehicle according to claim 1, characterized in that, It further includes a temperature sensor that collects the ambient temperature in real time and generates an analog signal output for: After the ADC sampling unit acquires an analog signal and converts it into a digital signal, the MCU calculates and obtains a compensation voltage according to a preset temperature-voltage compensation comparison table, and compensates the driving voltage output to the gate of the N-MOS transistor.

8. The filter circuit of the large-load driverless engineering vehicle according to claim 7, characterized in that The temperature sensor and the N-MOS transistor are coupled through a heat sink.

9. The filtering circuit of the large-load driverless engineering vehicle according to claim 1, characterized in that, It further includes: A body diode is connected in parallel across the two ends of the N-MOS transistor, its anode is connected to the source of the N-MOS transistor, and its cathode is connected to the drain of the N-MOS transistor.

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