Multi-sensor signal fusion circuit

Abstract

The invention relates to the technical field of signal processing, and discloses a multi-sensor signal fusion circuit which is characterized in that a signal input conditioning circuit amplifies and conditions input signals of multiple paths of sensors respectively, can realize standardized processing according to output characteristics of different sensors, and lays a foundation for subsequent precise fusion; the operational amplifier isolation feedback circuit feeds back a fusion signal of the parallel output circuit to the signal input conditioning circuit through forming a voltage follower, so that the inherent error of a one-way conduction characteristic element in the parallel output circuit can be effectively counteracted, and meanwhile, the influence of temperature drift on the signal precision is avoided; a final fusion signal is determined only by a sensor input signal and conditioning circuit parameters, the fusion precision is greatly improved, and the problem that a traditional simulation fusion scheme is insufficient in precision is solved.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and more specifically to a multi-sensor signal fusion circuit. Background Technology

[0002] With the rapid development of intelligent sensing and industrial automation technologies, modern electronic and electrical systems place higher demands on the real-time processing and intelligent fusion of information from multiple sensors. In safety-critical applications such as fail-safe systems, robot emergency obstacle avoidance, and monitoring of extreme environmental parameters, to avoid system misjudgments caused by the failure or interference of a single sensor, it is necessary to quickly extract the minimum value signal from multiple identical or different types of sensors and use this signal as the basis for system decision-making, control, or safety protection—this "minimum value fusion" strategy is a core requirement for improving the robustness and reliability of sensing systems.

[0003] Currently, the technical solutions for achieving minimum value selection and fusion of multi-sensor signals mainly fall into two categories: One approach is the digital processing solution. This solution requires an independent signal conditioning circuit and analog-to-digital converter (ADC) for each sensor, significantly increasing hardware cost, power consumption, and board area. Multi-channel sampling makes it difficult to guarantee strict timing synchronization, and even small delays in dynamic scenarios can easily lead to misjudgment of minimum values. Software algorithm execution and interrupt response introduce unavoidable delays, failing to meet high real-time requirements.

[0004] The second approach is the analog circuit scheme. Existing analog circuit schemes mostly use simple comparator structures based on diodes or operational amplifiers (such as multiple diodes connected in a common anode configuration). The forward voltage drop of the diodes introduces a fixed error, and this voltage drop drifts with temperature changes, which seriously affects the measurement accuracy of the sensing signal. Summary of the Invention

[0005] This invention provides a multi-sensor signal fusion circuit to solve the problem of how to improve the measurement accuracy of the fused signal from multiple sensors.

[0006] This invention provides a multi-sensor signal fusion circuit, comprising: a signal input conditioning circuit, an operational amplifier isolation feedback circuit, and a parallel output circuit. The first terminal of the signal input conditioning circuit receives multiple sensor signals, and the second terminal of the signal input conditioning circuit is connected to the first terminal of the parallel output circuit. The signal input conditioning circuit amplifies and conditions the multiple sensor input signals respectively. The first terminal of the operational amplifier isolation feedback circuit is connected to the second terminal of the parallel output circuit, and the second terminal of the operational amplifier isolation feedback circuit is connected to the third terminal of the signal input conditioning circuit. The operational amplifier isolation feedback circuit forms a voltage follower. The third terminal of the parallel output circuit is connected to a reference voltage, and the fourth terminal of the parallel output circuit outputs a fused signal. The parallel output circuit receives the conditioned signals output from the multiple signal input conditioning circuits and fuses the conditioned signals into a single signal based on its unidirectional conduction characteristic. This fused signal is the minimum value signal among the conditioned signals.

[0007] In one optional implementation, the signal input conditioning circuit includes: a plurality of signal input conditioning sub-circuits, wherein a sensor signal is input to a first terminal of each signal input conditioning sub-circuit, a second terminal of each signal input conditioning sub-circuit is connected to a first terminal of a parallel output circuit, a third terminal of each signal input conditioning sub-circuit is connected to a second terminal of an operational amplifier isolation feedback circuit, and each signal input conditioning sub-circuit is used to amplify and condition one sensor input signal respectively.

[0008] In one optional implementation, the signal input conditioning sub-circuit includes: a first operational amplifier and a first feedback branch, wherein the non-inverting input terminal of the first operational amplifier is grounded, the inverting input terminal of the first operational amplifier is connected to a sensor signal, the inverting input terminal of the first operational amplifier is connected to a first terminal of the first feedback branch, the output terminal of the first operational amplifier is connected to a first terminal of a parallel output circuit, and the second terminal of the first feedback branch is connected to a second terminal of the operational amplifier isolation feedback circuit.

[0009] In one optional implementation, the signal input conditioning sub-circuit further includes an input branch and a first ground branch, wherein the non-inverting input terminal of the first operational amplifier is grounded through the first ground branch, and the inverting input terminal of the first operational amplifier is connected to a sensor signal through the input branch.

[0010] In one alternative implementation, both the input branch and the first ground branch include at least one resistor.

[0011] In one optional implementation, the operational amplifier isolation feedback circuit includes: a second operational amplifier and a second feedback branch, wherein the non-inverting input terminal of the second operational amplifier is connected to the second terminal of the parallel output circuit, the non-inverting input terminal of the second operational amplifier is connected to the first terminal of the second feedback branch, the inverting input terminal of the second operational amplifier is connected to its output terminal, and the output terminal of the second operational amplifier is connected to the third terminal of the signal input conditioning circuit and the second terminal of the second feedback branch.

[0012] In one alternative implementation, the operational amplifier isolation feedback circuit further includes a second ground branch, wherein the output terminal of the second operational amplifier is grounded through the second ground branch.

[0013] In one alternative implementation, both the second feedback branch and the second grounding branch include at least one resistor.

[0014] In one optional implementation, the parallel output circuit includes: a plurality of unidirectional conduction switches and a current-limiting resistor, wherein the first terminal of each unidirectional conduction switch is connected to the second terminal of a signal input conditioning sub-circuit, and the second terminal of each unidirectional conduction switch is connected to a reference voltage through the current-limiting resistor; the conduction direction of each unidirectional conduction switch is from the second terminal to the first terminal; the second terminals of all the unidirectional conduction switches are connected to a single point to form the third terminal of the parallel output circuit.

[0015] In one alternative implementation, the unidirectional conduction switch is a diode, wherein the cathode of the diode is connected to the second terminal of a signal input conditioning sub-circuit, and the anode of each diode is connected to a reference voltage through a current-limiting resistor.

[0016] In this invention, the operational amplifier isolation feedback circuit, by forming a voltage follower, feeds back the fused signal from the parallel output circuit to the signal input conditioning circuit. This can offset the inherent errors of the unidirectional conduction components in the parallel output circuit (such as forward conduction voltage drop). Furthermore, the signal input conditioning circuit amplifies and conditions the signals from multiple sensors separately, ensuring that the amplitude of the conditioned signal is standardized. Ultimately, the fused signal is determined only by the sensor input signal and the parameters of the conditioning circuit, significantly reducing errors and minimizing the impact of temperature drift on accuracy, thus solving the problem of insufficient accuracy in traditional analog fusion schemes.

[0017] In this invention, the parallel output circuit directly achieves hardware-level minimum signal filtering and fusion based on unidirectional conduction characteristics, eliminating the need for analog-to-digital conversion (ADC), software algorithm calculation, and interrupt response processes in digital solutions. The hardware link transmission delay between the signal input conditioning circuit and the parallel output circuit is low, enabling rapid response to sensor signal changes. This meets the stringent real-time requirements of safety-critical applications such as fail-safe systems and robot emergency obstacle avoidance, and avoids the risk of misjudgment caused by delays in digital solutions.

[0018] In this invention, on the one hand, the fusion strategy of "taking the minimum value of multiple sensor signals" can avoid system misjudgment when a single sensor fails or is interfered with, thus improving the robustness of the sensing system; on the other hand, the functions of each module of the circuit work together (conditioning circuit preprocessing, feedback circuit error correction, and parallel circuit precise fusion), without complex digital processing devices, the hardware structure is stable, reducing system anomalies caused by insufficient computing power or program failures, and adapting to complex working conditions such as industrial automation and extreme environment monitoring.

[0019] In this invention, the signal input conditioning circuit "absorbs and conditions" multiple sensor signals separately. It can independently adjust the conditioning parameters according to the output characteristics of different sensors (such as amplitude range and signal strength), without having to make additional changes to the overall circuit structure due to differences in sensor type. This broadens the circuit's adaptability to various types of sensors such as temperature, pressure, and displacement, and improves application flexibility. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a composition diagram of a multi-sensor signal fusion circuit according to an embodiment of the present invention; Figure 2 This is a detailed circuit structure diagram of the multi-sensor signal fusion circuit according to an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It is understood that before using the technical solutions disclosed in the various embodiments of the present invention, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in the present invention and their authorization should be obtained in accordance with relevant laws and regulations through appropriate means.

[0024] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] Currently, the technical solutions for achieving minimum value selection and fusion of multi-sensor signals mainly fall into two categories: One approach is the digital processing solution. This solution requires configuring an independent signal conditioning circuit and analog-to-digital converter (ADC) for each sensor. First, all raw sensor signals are converted into digital quantities. Then, a software algorithm runs through a microprocessor (MCU), digital signal processor (DSP), or programmable logic device (FPGA) to compare the digital quantities and select the minimum value. While this solution can implement complex comparison logic and offers high flexibility, it has inherent drawbacks: First, the configuration of multiple ADCs and high-performance processors significantly increases hardware costs, system power consumption, and board space. Second, multi-channel signal sampling is difficult to guarantee strict timing synchronization; even slight sampling delays in dynamic scenarios can easily lead to misjudgment of the minimum value. Furthermore, the execution of the software algorithm and interrupt response process inevitably introduce delays, making it unsuitable for applications with extremely high real-time requirements.

[0026] The second approach is the analog circuit scheme. Existing analog circuit schemes often employ simple comparator structures based on diodes or operational amplifiers (op-amps). A typical design utilizes multiple diodes connected in a common-anode configuration to achieve unidirectional minimum value selection: multiple input sensor signals are first processed by the op-amp conditioning circuit, and then a fused signal is output through the common-anode diodes. The amplitude of this fused signal is equal to the sum of the minimum value of the multiple conditioned signals and the forward voltage drop of the diodes. However, this simple analog scheme has significant shortcomings: the forward voltage drop of the diodes themselves introduces a fixed error, and this voltage drop drifts significantly with changes in ambient temperature, severely affecting the measurement accuracy of the sensor signals and making it difficult to meet the requirements of high-precision fusion.

[0027] In summary, neither of the existing two types of multi-sensor signal minimum value fusion schemes can simultaneously meet the application requirements of real-time performance, low cost, and high accuracy. There is an urgent need for a multi-sensor signal fusion technology that can solve the above-mentioned defects.

[0028] Addressing the shortcomings of existing multi-sensor signal minimum value fusion schemes (digital schemes are costly and have poor real-time performance, while analog schemes suffer from accuracy interference from diode voltage drop), this embodiment provides a multi-sensor signal fusion circuit to meet the requirements of "high precision, high real-time performance, and low cost" for signal fusion in safety-critical applications (such as fail-safe systems and robot emergency obstacle avoidance). Figure 1As shown, it includes: signal input conditioning circuit 1, operational amplifier isolation feedback circuit 2, and parallel output circuit 3.

[0029] like Figure 1 As shown, the first terminal of the signal input conditioning circuit 1 receives multiple sensor signals, and the second terminal of the signal input conditioning circuit 1 is connected to the first terminal of the parallel output circuit 3. The signal input conditioning circuit 1 is used to amplify and condition the multiple sensor input signals respectively.

[0030] Signal input conditioning circuit 1, as the pre-processing unit of the entire fusion circuit, plays a crucial role in resolving the issues of inconsistent amplitude and numerous interference signals in the original signals from different sensors. The first terminal of this circuit is specifically designed to receive the original signals output by multiple sensors (which can be voltage-type signals or standardized signals adapted to different sensor types). Because the output characteristics of different sensors vary (e.g., some sensors output weak signals, while others have large amplitude fluctuations), directly inputting these signals into the subsequent fusion stage could easily lead to "minimum value misjudgment." Therefore, signal input conditioning circuit 1 needs to independently amplify and condition each input sensor signal. Through targeted signal amplitude adjustment and interference suppression, all original signals are uniformly converted into standardized signals with amplitude ranges adapted to subsequent fusion processing, laying the foundation for the precise minimum value selection of the parallel output circuit 3. In terms of connection, the second terminal of the signal input conditioning circuit 1 is directly connected to the first terminal of the parallel output circuit 3. This connection path provides a stable transmission channel for the conditioned standardized signal, ensuring that multiple signals can be synchronously transmitted to the fusion stage. Simultaneously, the signal input conditioning circuit 1 also has a third terminal, which is used to establish a feedback connection with the operational amplifier isolation feedback circuit 2, receiving stable feedback signals from subsequent stages, thereby dynamically optimizing its own conditioning parameters and ensuring the accuracy of signal preprocessing.

[0031] like Figure 1 As shown, the first terminal of the operational amplifier isolation feedback circuit 2 is connected to the second terminal of the parallel output circuit 3, and the second terminal of the operational amplifier isolation feedback circuit 2 is connected to the third terminal of the signal input conditioning circuit 1. The operational amplifier isolation feedback circuit 2 is used to form a voltage follower.

[0032] The operational amplifier isolation feedback circuit 2 is the "accuracy guarantee core" of the entire fusion circuit. Its design purpose is to eliminate the influence of the "inherent error of unidirectional conducting elements (such as forward voltage drop)" on the fusion result in traditional analog fusion schemes. From the connection logic perspective, the first terminal of this circuit is connected to the second terminal of the parallel output circuit 3, which is used to acquire the fusion signal output by the parallel output circuit 3 in real time; its second terminal is connected to the third terminal of the signal input conditioning circuit 1, forming a closed-loop feedback link from "fusion output" to "signal conditioning".

[0033] The core function of the operational amplifier isolation feedback circuit 2 is to form a voltage follower. Utilizing the characteristics of the voltage follower—"high input impedance, low output impedance, and output voltage highly consistent with the input voltage"—it achieves isolation between the feedback signal and the parallel output circuit 3, preventing interference signals in the feedback loop from being transmitted back to the fusion stage and affecting the stability of the minimum value selection. On the other hand, it feeds back the acquired fused signal to the signal input conditioning circuit 1 in a distortion-free and low-delay form, enabling the signal input conditioning circuit 1 to adjust the amplification factor of the original sensor signal in real time according to the state of the final fused signal. This counteracts the inherent error caused by the unidirectional conduction characteristic of the parallel output circuit 3, ensuring that the subsequent output fused signal is only related to the original sensor signal and conditioning parameters.

[0034] like Figure 1 As shown, the third terminal of the parallel output circuit 3 is connected to the reference voltage VREF, and the fourth terminal of the parallel output circuit 3 outputs a fused signal. The parallel output circuit 3 is used to receive the conditioned signal output by the multi-channel signal input conditioning circuit 1, and fuse the conditioned signal into one signal based on the unidirectional conduction characteristic. The fused signal is the minimum value signal among the conditioned signals.

[0035] The parallel output circuit 3, as the "core fusion and output unit" of the entire fusion circuit, plays a crucial role in "real-time minimum value selection and stable output of the fused signal." From the connection perspective, the first terminal of this circuit is connected to the second terminal of the signal input conditioning circuit 1 to receive the pre-processed multi-channel standardized signals; its third terminal is specifically connected to the reference voltage VREF, which provides a stable reference potential for signal fusion, preventing amplitude drift of the fused signal due to external voltage fluctuations and ensuring the consistency of minimum value selection; its fourth terminal serves as the final output terminal of the entire fusion circuit, used to output the fused target signal.

[0036] The core operating logic of the parallel output circuit 3 is based on the "unidirectional conduction characteristic": after receiving multiple standardized signals, the amplitude of each signal is compared and filtered in real time through a unidirectional conduction mechanism. Only when the amplitude of a certain signal is the minimum value among all input signals can that signal meet the unidirectional conduction condition and be transmitted to the output terminal; other signals with amplitudes greater than the minimum value are blocked because they do not meet the conduction condition, ultimately achieving the fusion of multiple signals into a single fused signal that only reflects the "minimum value". At the same time, thanks to the closed-loop feedback constructed by the operational amplifier isolation feedback circuit 2, the fused signal output by the parallel output circuit 3 has eliminated the inherent error influence of the unidirectional conduction element, possessing both real-time performance and high precision, and can be directly used as the basis for decision control or safety protection in safety-critical systems.

[0037] In summary, the signal input conditioning circuit 1, the operational amplifier isolation feedback circuit 2, and the parallel output circuit 3 form a complete multi-sensor signal minimum value fusion scheme through the collaborative workflow of "preprocessing-feedback correction-fusion output". This scheme avoids the high cost and delay problems of digital schemes and solves the accuracy defects of traditional analog schemes. It can effectively adapt to application scenarios with stringent signal fusion performance requirements.

[0038] In some optional embodiments, the signal input conditioning circuit 1 includes: a plurality of signal input conditioning sub-circuits, wherein a sensor signal is input at the first terminal of each signal input conditioning sub-circuit, the second terminal of each signal input conditioning sub-circuit is connected to the first terminal of the parallel output circuit 3, the third terminal of each signal input conditioning sub-circuit is connected to the second terminal of the operational amplifier isolation feedback circuit 2, and each signal input conditioning sub-circuit is used to amplify and condition one sensor input signal respectively.

[0039] Specifically, the core function of each signal input conditioning sub-circuit is to independently amplify and condition the sensor input signal it receives. To address potential issues such as low amplitude, inconsistent amplitude, or slight noise in the original sensor signal, the signal input conditioning sub-circuit performs targeted amplification to adjust the signal amplitude to a uniform range suitable for minimum value judgment by the parallel output circuit 3. At the same time, it suppresses noise interference through a signal optimization mechanism, ensuring that the conditioned signal has both sufficient amplitude sensitivity to support accurate minimum value selection and a low noise level to avoid misjudgment.

[0040] This "one-channel-one-conditioning" design can flexibly adapt to the unique signal characteristics of each sensor, solving the problem that traditional "unified conditioning circuits" cannot take into account the differences of multiple signals. This lays a key foundation for the entire multi-sensor signal fusion circuit to achieve "high precision and high reliability" minimum value fusion.

[0041] In some alternative implementations, taking the signal input conditioning circuit 1 as an example, which includes three signal input conditioning sub-circuits, such as... Figure 2 As shown, the signal input conditioning sub-circuit includes: a first operational amplifier (i.e., U1, U2, U3) and a first feedback branch (i.e., R3, R6, R9).

[0042] like Figure 2 As shown, the non-inverting input of the first operational amplifier is grounded, the inverting input of the first operational amplifier is connected to a sensor signal, the inverting input of the first operational amplifier is connected to the first end of the first feedback branch, the output of the first operational amplifier is connected to the first end of the parallel output circuit 3 (i.e., D1, D2, D3), and the second end of the first feedback branch is connected to the second end of the operational amplifier isolation feedback circuit 2 (i.e., R12).

[0043] Specifically, the first operational amplifier, as the core signal amplification component of the signal input conditioning sub-circuit, has its port connections and functional design designed to achieve the signal conditioning goal of "low interference and high stability." The non-inverting input of the first operational amplifier is grounded. This grounding design provides a zero-potential reference for the operational amplifier. On the one hand, the common-mode rejection capability of the operational amplifier effectively suppresses the influence of common-mode interference in the external environment (such as electromagnetic coupling interference in industrial scenarios) on the signal amplification process, preventing common-mode noise from being superimposed on the conditioned signal and causing amplitude deviation. On the other hand, the zero-potential reference ensures that the operational amplifier has a unified amplitude reference standard when amplifying sensor signals, preventing inconsistencies in amplification accuracy between different conditioning sub-circuits due to reference potential fluctuations, and providing a unified amplitude dimension for subsequent fusion and screening of multiple signals.

[0044] The inverting input of the first operational amplifier is dedicated to a single original sensor signal. The core advantage of this inverting input method is that it reduces interference coupling between the sensor signal and the operational amplifier's input stage during transmission. Furthermore, by cooperating with the subsequent first feedback branch, it quickly constructs a negative feedback amplification structure. When the original sensor signal is input to the inverting input, the negative feedback mechanism stabilizes the amplification coefficient, preventing amplification deviations caused by operational amplifier parameter drift (such as temperature drift and offset voltage). This ensures that the conditioned signal amplitude remains within the minimum value selection range of the parallel output circuit 3. Simultaneously, the inverting input of the first operational amplifier is directly connected to the first terminal of the first feedback branch. This connection is a crucial node in constructing the negative feedback loop, enabling the feedback signal to participate in real-time adjustment of the operational amplifier's input signal, providing a path for dynamically correcting errors during the amplification process.

[0045] The output of the first operational amplifier is connected to the first terminal of the parallel output circuit 3. This connection provides a stable transmission path for the conditioned signal. After amplification and interference suppression by the operational amplifier, the signal is delivered to the parallel output circuit 3 in a standardized amplitude form (such as a voltage range adapted to the unidirectional conduction characteristics of the parallel output circuit 3) as a "qualified signal source" for subsequent minimum value fusion. Compared to the unconditioned original sensor signal, this output signal not only meets the fusion requirements in terms of amplitude but also has a lower noise level and higher amplitude stability. It can directly support the parallel output circuit 3 to perform accurate amplitude comparison and minimum value selection for multiple signals, avoiding fusion misjudgments caused by signal quality issues.

[0046] The first feedback branch, as the core link connecting the signal input conditioning sub-circuit to the closed-loop feedback of the entire fusion circuit, directly determines the realization of the "error cancellation" function through its port connection logic. The first end of the first feedback branch is connected to the inverting input of the first operational amplifier, and the second end is connected to the second end of the operational amplifier isolation feedback circuit 2. Combined with the design described in this technical disclosure that "the operational amplifier isolation feedback circuit 2 constitutes a voltage follower, providing real-time feedback of the fusion signal from the parallel output circuit 3," this connection method enables the first feedback branch to introduce the stable fusion signal output by the operational amplifier isolation feedback circuit 2 into the negative feedback loop of the first operational amplifier.

[0047] Specifically, when the parallel output circuit 3 generates an inherent voltage drop error due to its unidirectional conduction characteristics (such as the forward conduction of a diode), the operational amplifier isolation feedback circuit 2 will transmit the fused signal carrying this error information to the first feedback branch in the form of a voltage follower. The first feedback branch will then feed the feedback signal back to the inverting input of the first operational amplifier in real time, forming a superposition adjustment with the original sensor signal. Through the automatic adjustment mechanism of negative feedback, the first operational amplifier will dynamically fine-tune its amplification factor according to the error information of the feedback signal, so that the conditioned output signal can just offset the voltage drop error that may be generated by the subsequent parallel output circuit 3. Ultimately, it is ensured that the fused signal output by the parallel output circuit 3 is determined only by the original sensor signal and the parameters of the conditioning circuit, and is not affected by the fluctuation of the characteristics of the unidirectional conduction element.

[0048] In addition, the first feedback branch also plays a role in stabilizing the working state of the first operational amplifier: by constructing deep negative feedback, it can effectively suppress the amplification performance drift of the first operational amplifier caused by power supply voltage fluctuations and ambient temperature changes, ensuring that its amplification factor always remains within the preset accurate range, providing a guarantee for the stable conditioning of single-channel sensor signals, and thus laying the foundation for the accurate fusion of multiple signals.

[0049] In some alternative implementations, such as Figure 2 As shown, the signal input conditioning sub-circuit also includes: an input branch (i.e., R1, R4, R7) and a first ground branch (i.e., R2, R5, R8). The non-inverting input terminal of the first operational amplifier is grounded through the first ground branch, and the inverting input terminal of the first operational amplifier is connected to a sensor signal through the input branch.

[0050] The first grounding branch is a potential reference and noise suppression channel specifically designed for the non-inverting input of the first operational amplifier. Its core function is to keep the non-inverting input of the first operational amplifier stably in a zero potential reference state through a specific grounding path.

[0051] The non-inverting input of the first operational amplifier is not directly grounded, but is grounded through the first grounding branch. This branch provides a "low impedance, low noise" grounding path for the non-inverting input. On the one hand, it can effectively suppress common-mode interference in the external environment (such as electromagnetic coupling noise in industrial scenarios and common-mode signals introduced by power fluctuations). Since the common-mode rejection capability of the operational amplifier depends on the stability of the common-mode potential of the input signals at both ends, the first grounding branch fixes the non-inverting input to zero potential, so that when the operational amplifier processes the sensor signal input at the inverting input, the common-mode input potential remains stable, avoiding amplification accuracy deviation caused by common-mode interference. On the other hand, this branch can avoid potential drift at the in-phase terminal: if the in-phase terminal is directly grounded or the grounding path impedance is too large, potential fluctuations are easily caused by weak current in the grounding loop and changes in ambient temperature. The first grounding branch, through optimized grounding path design, ensures the long-term stability of the zero potential reference at the in-phase terminal, providing a unified potential reference for the conditioning sub-circuits of different signal inputs. When multiple conditioning sub-circuits work in parallel, the unified zero potential reference can ensure that the amplitude dimension of each conditioned signal is consistent, avoiding misjudgment during the minimum value screening of the subsequent parallel output circuit due to reference differences, and laying a reference foundation for the accurate fusion of multi-sensor signals.

[0052] The input branch is a dedicated transmission channel for the raw sensor signal to enter the inverting input of the first operational amplifier. Its core design principle is to achieve "directional signal transmission, fidelity of original characteristics, and protection of the inverting input." From a connection perspective, the inverting input of the first operational amplifier is not directly connected to the sensor signal, but rather through the input branch. This branch first ensures the directional transmission of the raw sensor signal, guaranteeing that the signal output from a single sensor is only sent to the corresponding signal input conditioning sub-circuit, avoiding crosstalk caused by sharing a transmission path with other sensor signals. Since this embodiment adopts a parallel design of "one sensor corresponding to one conditioning sub-circuit," the dedicated transmission characteristics of the input branch guarantee the independence of each signal from the source, preventing interference between different sensor signals from affecting the authenticity of the raw signal. Secondly, the input branch ensures the fidelity of the raw signal characteristics: sensor signals are easily affected by line impedance and external electromagnetic interference during transmission. In the event of amplitude attenuation or noise superposition, the input branch optimizes impedance matching and interference shielding design of the transmission path (such as reducing parasitic capacitance and suppressing external electromagnetic coupling) to preserve the characteristics of the original sensor signal to the maximum extent. This ensures that the signal entering the inverting input terminal accurately reflects the sensor's detection state, providing a reliable original signal foundation for the subsequent precise amplification and conditioning of the first operational amplifier. In addition, the input branch also protects the inverting input terminal of the first operational amplifier: when the sensor outputs an overvoltage signal due to abnormal operating conditions, the input branch can use its own signal buffering characteristics (without involving specific components, only demonstrating the function) to prevent the overvoltage signal from directly impacting the inverting input terminal, preventing damage to the operational amplifier and ensuring the long-term stable operation of the signal conditioning sub-circuit.

[0053] In summary, the input branch and the first ground branch work synergistically in the signal input conditioning sub-circuit: the input branch provides a "pure and independent" raw sensor signal to the inverting input terminal, while the first ground branch provides a "stable and low-noise" zero-potential reference to the non-inverting input terminal. Together, they create high-precision amplification conditions for the first operational amplifier, enabling it to accurately amplify and condition the raw signal transmitted with high fidelity based on a stable reference potential, and output a standardized signal that meets the fusion requirements of the subsequent parallel output circuit 3. This, in turn, supports the entire multi-sensor signal fusion circuit in achieving its core objective of "eliminating errors in unidirectional conducting elements and improving fusion accuracy."

[0054] In some alternative implementations, such as Figure 2As shown, the operational amplifier isolation feedback circuit 2 includes: a second operational amplifier U4 and a second feedback branch (i.e., R11). The non-inverting input terminal of the second operational amplifier U4 is connected to the second terminal (i.e., the cathodes of D1, D2, and D3) of the parallel output circuit 3. The non-inverting input terminal of the second operational amplifier U4 is connected to the first terminal of the second feedback branch. The inverting input terminal of the second operational amplifier U4 is connected to its output terminal. The output terminal of the second operational amplifier U4 is connected to the third terminal of the signal input conditioning circuit 1 (i.e., R3, R6, and R9) and the second terminal of the second feedback branch.

[0055] The second operational amplifier U4, as the core signal processing component of the operational amplifier isolation feedback circuit 2, has its port connection design directly determining the realization of the core function of a "voltage follower." The characteristics of a voltage follower are crucial for ensuring feedback accuracy and signal isolation. From the port connection perspective, the inverting input terminal of the second operational amplifier U4 is directly connected to its output terminal. This connection method is the basis for constructing a voltage follower. According to the working principle of operational amplifiers, when the inverting input terminal is shorted to the output terminal, the circuit automatically adjusts the output voltage to keep the voltage at the inverting input terminal consistent with the voltage at the non-inverting input terminal, ultimately forming the characteristic of "output voltage following the input voltage at the non-inverting input terminal." This feature gives the second operational amplifier U4 two key advantages: First, high input impedance, which can avoid signal attenuation or distortion caused by low input impedance when the operational amplifier isolation feedback circuit 2 acquires signals from the parallel output circuit 3, ensuring that the acquired fused signal can truly reflect the output state of the parallel output circuit 3; Second, low output impedance, which allows the feedback signal to be transmitted to the signal input conditioning circuit 1 in a low-loss, delay-free manner, avoiding feedback signal voltage drop or transmission delay caused by excessively high output impedance, and ensuring timely error correction.

[0056] The non-inverting input of the second operational amplifier U4 is connected to the second terminal of the parallel output circuit 3, which serves as the "acquisition entry point" for the feedback signal. Combined with the function of the parallel output circuit 3 to "output a minimum fusion signal based on unidirectional conduction characteristics," this connection allows the second operational amplifier U4 to acquire the fusion signal output by the parallel output circuit 3 in real time. Whether it's the rapid changes in sensor signals in a dynamic scene leading to fusion signal updates, or the stable output of the fusion signal in a static scene, the non-inverting input of the second operational amplifier U4 can accurately capture this signal, providing a "real-time and accurate error reference" for subsequent feedback correction, thus preventing error correction failure due to feedback signal lag or distortion.

[0057] The second feedback branch, serving as the "dynamic optimization unit" of the operational amplifier isolation feedback circuit 2, optimizes its port connections and functions to address the inherent limitations of the voltage follower. From a connection logic perspective, the first terminal of the second feedback branch is connected to the non-inverting input of the second operational amplifier U4, and the second terminal is connected to the output of the second operational amplifier U4, forming an auxiliary feedback path spanning the input and output terminals of the operational amplifier. In this technical solution, although the voltage follower can achieve stable signal tracking, its response to rapidly changing fused signals may be delayed due to the bandwidth limitation of the operational amplifier itself. Furthermore, under certain operating conditions, insufficient phase margin can easily lead to circuit oscillations, affecting feedback stability. The existence of the second feedback branch precisely solves this problem: On the one hand, it can accelerate the response speed of the second operational amplifier U4 to changes in the fused signal through the auxiliary feedback path. When the fused signal of the parallel output circuit 3 fluctuates rapidly due to changes in the sensor input, the second feedback branch can shorten the transmission path of the feedback signal, enabling the second operational amplifier U4 to adjust the output voltage more quickly, ensuring the synchronization of the feedback signal and the fused signal, and avoiding the error correction lag of the signal input conditioning circuit 1 due to response delay. On the other hand, the second feedback branch can optimize the phase margin of the second operational amplifier U4 and suppress circuit oscillation. By adjusting the impedance characteristics of the second feedback branch (which is clearly defined as a resistive element in the disclosure document), the input and output phase relationship of the operational amplifier can be balanced, preventing the feedback signal from superimposing and interfering with the input signal due to excessive phase difference, and ensuring the overall stability of the operational amplifier isolation feedback circuit 2.

[0058] The output of the second operational amplifier U4 also serves as a "feedback signal transmission hub": it is connected not only to its own inverting input to form a voltage follower, but also to the third terminal of the signal input conditioning circuit 1 and the second terminal of the second feedback branch. This multi-connection design achieves "feedback signal splitting and precise delivery." Its output takes the feedback signal, which has been processed by the voltage follower and optimized by the second feedback branch, and sends it back to the non-inverting input through the second feedback branch to complete dynamic optimization. On the other hand, through its connection with the third terminal of the signal input conditioning circuit 1, it sends the feedback signal to the signal input conditioning circuit 1 (specifically, the feedback node of each signal input conditioning sub-circuit). Combined with the function of signal input conditioning circuit 1 in "amplifying and conditioning the sensor signal", the feedback signal can be used as an "error correction reference" for the conditioning circuit. This allows signal input conditioning circuit 1 to dynamically adjust the amplification factor of the original sensor signal according to the state of the final fused signal, thereby offsetting the inherent error caused by the forward conduction voltage drop of the unidirectional conducting element (such as a diode) in the parallel output circuit 3. Ultimately, this achieves the core technical objective stated in the disclosure document that "the fused signal VOUT is only related to the input signal and the resistance of signal input conditioning circuit 1, and is not affected by the diode voltage drop".

[0059] In summary, the second operational amplifier U4 achieves stable acquisition and isolation of the feedback signal by constructing a voltage follower, and the second feedback branch optimizes dynamic performance and stability through auxiliary feedback. The two work together and are connected through precise ports, making the operational amplifier isolation feedback circuit 2 an "error correction bridge" connecting the parallel output circuit 3 and the signal input conditioning circuit 1. This fundamentally solves the defect of diode voltage drop affecting accuracy in traditional analog fusion schemes and provides key support for the high-precision realization of multi-sensor signal fusion.

[0060] In some alternative implementations, such as Figure 2 As shown, the operational amplifier isolation feedback circuit 2 also includes a second grounding branch (i.e., R12), wherein the output terminal of the second operational amplifier U4 is grounded through the second grounding branch.

[0061] The second grounding branch plays a crucial role in calibrating the DC bias at the output of the second operational amplifier U4. In the operational amplifier isolation feedback circuit 2, the second operational amplifier U4 needs to output a stable and accurate feedback signal to support the signal input conditioning circuit 1 in offsetting the forward voltage drop error of the diodes in the parallel output circuit 3. However, due to the characteristics of the operational amplifier itself (such as input offset voltage and temperature drift), there may be a slight DC potential shift at its output. If this shift is transmitted directly to the signal input conditioning circuit 1 without calibration, it will cause a deviation in the amplification factor of the conditioning circuit, thus affecting the accuracy of the final fused signal (VOUT), violating the technical objective that "VOUT is only related to the input signal and the resistance of the signal input conditioning circuit 1." The second grounding branch, by providing a low-impedance DC discharge path for the output of the second operational amplifier U4, can stabilize the DC offset potential at the output within a reasonable range close to ground potential, ensuring that the DC component of the feedback signal accurately reflects the fused signal state of the parallel output circuit 3, rather than being mixed with the DC offset error of the operational amplifier itself. This lays the foundation for the accurate error offset of the subsequent signal input conditioning circuit 1.

[0062] The second grounding branch plays a crucial role in improving the dynamic stability of the operational amplifier isolation feedback circuit 2. In scenarios where multi-sensor signals change dynamically (such as rapid signal switching during emergency obstacle avoidance by a robot), the output of the second operational amplifier U4 needs to quickly respond to changes in the fused signal of the parallel output circuit 3 and adjust the feedback signal in real time. If the output accumulates excess charge or experiences transient voltage fluctuations due to transient response, it will slow down the response speed of the operational amplifier and may even cause circuit oscillations (complementing the function of the second feedback branch in "improving phase margin"), disrupting the dynamic balance of the feedback link. The second grounding branch can quickly discharge transient charge and fluctuating voltage at the output, providing a stable dynamic operating environment for the second operational amplifier U4. This ensures that its output can quickly and without delay follow the changes in the fused signal at the in-phase input, avoiding asynchrony between the feedback signal and the fused signal due to dynamic response lag. This, in turn, ensures that the signal input conditioning circuit 1 can complete error cancellation in real time and accurately, ultimately achieving high precision and high real-time performance in multi-sensor signal fusion.

[0063] In summary, the second grounding branch, through its three core functions of "calibrating DC bias, suppressing noise interference, and ensuring dynamic stability," together with the second operational amplifier U4 and the second feedback branch, improves the performance of the operational amplifier isolation feedback circuit 2. This ensures that the circuit can continuously output accurate and stable feedback signals, providing key hardware support for the entire multi-sensor signal fusion circuit to eliminate diode forward voltage drop errors and improve fusion accuracy. This fully meets the improvement goals proposed in the technical disclosure document for the accuracy defects of traditional analog solutions.

[0064] In some alternative implementations, such as Figure 2 As shown, the parallel output circuit 3 includes: multiple unidirectional conduction switches (i.e., D1, D2, D3) and a current-limiting resistor R10. The first terminal of each unidirectional conduction switch is connected to the second terminal of a signal input conditioning sub-circuit (i.e., U1, U2, U3). The second terminal of each unidirectional conduction switch is connected to the reference voltage VREF through the current-limiting resistor. The conduction direction of each unidirectional conduction switch is from the second terminal to the first terminal. The second terminals of all the unidirectional conduction switches are connected to a single point to form the third terminal of the parallel output circuit 3.

[0065] Multiple unidirectional conduction switches are the core components of the parallel output circuit 3 for completing minimum value screening. Their "one switch per circuit" configuration and unidirectional conduction characteristics directly determine the accuracy and real-time performance of minimum value fusion.

[0066] Each unidirectional conduction switch has its first terminal connected to the second terminal of a signal input conditioning sub-circuit. This "one-to-one" connection ensures that each standardized signal amplified and conditioned by the signal input conditioning sub-circuit can be transmitted independently and without crosstalk to the corresponding unidirectional conduction switch. Whether it is the difference in signal amplitude caused by the difference in detection parameters between different sensors, or the slight change in signal caused by environmental fluctuations of the same type of sensor, they can all enter the fusion stage through a dedicated switch channel. This avoids signal interference or amplitude superposition caused by multiple signals sharing the same transmission path, ensuring the original characteristics of each conditioned signal from the source and laying the foundation for subsequent accurate selection of the minimum value.

[0067] Each unidirectional conduction switch is set to conduct from the second terminal to the first terminal. This directional design is the core logic for achieving "minimum value filtering." Combined with the characteristic of the unidirectional conduction switch that "only allows signals to flow in a specific direction," and the coordination of the subsequent current-limiting resistor and the reference voltage VREF, when the conditioned signals (transmitted to the first terminal of the switch) arrive at the parallel output circuit 3, the switch will automatically determine whether to conduct based on the potential difference between the first and second terminals. The switch will only open when the potential of a conditioned signal (the potential at the first terminal) is lower than the reference potential at the second terminal, allowing that signal to flow from the first terminal to the second terminal. If the potential of any other conditioned signal is higher than the reference potential at the second terminal, the corresponding switch will remain closed, blocking signal flow. This "low-potential conduction, high-potential cut-off" mechanism can filter out the minimum value among all conditioned signals in real time—only the switch corresponding to the minimum value signal will conduct, while the rest are blocked. This naturally achieves the fusion of multiple signals into the "minimum value signal," perfectly meeting the core requirement of this technical solution for safety-critical applications (such as fail-safe systems and robot emergency obstacle avoidance) to "quickly extract the minimum value signal."

[0068] The second terminals of all unidirectional conduction switches are uniformly connected to a single point, which forms the third terminal of the parallel output circuit 3. This design is key to achieving "unified reference and centralized fusion". On the one hand, the common connection of the second terminals of all switches ensures that the second terminals of all unidirectional conduction switches are at the same reference potential. Regardless of which switch is turned on, the signal output from its second terminal will converge to this common node, avoiding amplitude deviation of the fused signal caused by potential differences in the second terminals of different switches. On the other hand, this common node (third terminal) is both the "summarized output terminal" of multiple conduction signals and the core hub for establishing connections with the current-limiting resistor and the operational amplifier isolation feedback circuit 2. Through this node, the minimum value signal after conduction can be stably output to the external system (such as the decision control unit), and at the same time, it can provide a real-time fused signal sampling source for the operational amplifier isolation feedback circuit 2, providing an accurate signal basis for subsequent feedback correction (eliminating the inherent error of the unidirectional conduction switches).

[0069] The current-limiting resistor is an important auxiliary component for ensuring the operational stability and component safety of the parallel output circuit 3. It is connected between the reference voltage VREF and the common second terminal (the third terminal of the parallel output circuit 3) of all unidirectional conducting switches. Its core functions are reflected in "current-limiting protection" and "reference stability". The reference voltage VREF serves as the source of the reference potential for the second terminal of the unidirectional conduction switch. If it is directly connected to the common node, the loop current may increase sharply due to the large voltage difference, which may damage the unidirectional conduction switch or the signal input conditioning sub-circuit. The current-limiting resistor, through its own impedance characteristics, can effectively limit the loop current when the reference voltage VREF is connected, keeping the current within a safe range, preventing components from burning out due to overcurrent, and ensuring the long-term reliable operation of the entire parallel output circuit 3.

[0070] In summary, multiple unidirectional conduction switches, through a design of "one-to-one connection, directional conduction, and common node aggregation," achieve real-time minimum value filtering and fusion of multi-channel conditioned signals. The current-limiting resistor, through its functions of "current-limiting protection and reference stabilization," ensures the precise operation of the switches. Their synergistic effect enables the parallel output circuit 3 to quickly extract the minimum value signal while ensuring the stability and security of signal fusion. Simultaneously, it provides a signal interface for error correction of the operational amplifier isolation feedback circuit 2 through the common node. Ultimately, this supports the entire multi-sensor signal fusion circuit in achieving the core technical goals of "high precision and high real-time performance," effectively solving the shortcomings of traditional analog fusion schemes such as "low filtering accuracy and easy component damage."

[0071] In some alternative implementations, such as Figure 2As shown, the unidirectional conduction switches are diodes (i.e., D1, D2, D3), wherein the cathode of the diode is connected to the second terminal of a signal input conditioning sub-circuit, and the anode of each diode is connected to the reference voltage VREF through a current-limiting resistor.

[0072] As a unidirectional switching diode, the connection method of "cathode connected to conditioning circuit and anode connected to reference voltage VREF through current limiting resistor" not only realizes the minimum value screening of multiple signals, but also solves the accuracy defects and safety risks of traditional solutions through the synergy of current limiting resistor, reference voltage VREF and operational amplifier isolation feedback circuit 2. It has become a key component supporting the "high precision, high real-time performance and high reliability" of the entire multi-sensor signal fusion circuit.

[0073] In a practical application scenario, refer to Figure 2 The operational amplifier isolation feedback circuit 2 consists of operational amplifier U4, resistors R11 and R12. The output terminal of U4 is connected to the inverting input terminal. One end of R11 is connected to the non-inverting input terminal of U4, and the other end is connected to the output terminal of U4. One end of R12 is connected to the output terminal of U4, and the other end is grounded to GND.

[0074] The parallel output circuit 3 consists of resistor R10 and diodes D1~D3, with VREF serving as the reference voltage source. D1~D3 are connected with a common anode.

[0075] Signal input conditioning circuit 1 consists of operational amplifiers U1~U3 and resistors R1~R9. VDD is the positive power supply, and VEE is the negative power supply, powering the operational amplifiers. U1 and R1~R3 ​​form a negative feedback amplifier circuit to amplify the input signal VIN1. U2 and R4~R6 form a negative feedback amplifier circuit to amplify the input signal VIN2. U3 and R7~R9 form a negative feedback amplifier circuit to amplify the input signal VIN3. One end of each of R3, R6, and R9 is connected to the inverting input terminal of the operational amplifier, and the other ends are connected together and connected to the output terminal of operational amplifier U4.

[0076] Due to the unidirectional conductivity of the diode, the output VOUT in the parallel output circuit 3 can merge multiple signals into a single signal, outputting the minimum value among the multiple signals. In the signal input conditioning circuit 1, the feedback resistor is no longer directly connected to the op-amp output, but is instead uniformly connected to the output of U4. Since the output of U4 is connected to the inverting input, forming a voltage follower, its output value follows the input value. Therefore, the op-amp isolation feedback circuit 2 effectively feeds back the output VOUT directly to the feedback resistor of the multi-signal input conditioning circuit 1. The VOUT output value is only related to the input signal and the resistor in the input signal conditioning circuit, and is no longer related to the diode voltage drop, that is:

[0077] in k 1. k 2. k 3 is a constant and can be precisely set by the resistor in the multi-channel signal input conditioning circuit 1, thereby effectively improving the measurement accuracy of the sensing signal.

[0078] Since the bandwidth of the op-amp voltage follower is limited, resistor R11 is set to connect the output terminal and the non-inverting input terminal of U4, so that U4 can feed back the output voltage VOUT to the signal input conditioning circuit 1 more quickly, improve dynamic performance, and avoid oscillation caused by insufficient phase margin of the op-amp voltage follower. At the same time, resistor R12 is set to further improve the working stability of the feedback circuit and ensure the robustness of the signal fusion circuit.

[0079] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A multi-sensor signal fusion circuit, characterized by, The application relates to a signal input conditioning circuit, an operational amplifier isolation feedback circuit and a parallel output circuit. The first end of the signal input conditioning circuit inputs multiple sensor signals, the second end of the signal input conditioning circuit is connected with the first end of the parallel output circuit, and the signal input conditioning circuit is used for respectively amplifying and conditioning multiple sensor input signals. The first end of the operational amplifier isolation feedback circuit is connected with the second end of the parallel output circuit, the second end of the operational amplifier isolation feedback circuit is connected with the third end of the signal input conditioning circuit, and the operational amplifier isolation feedback circuit is used for constituting a voltage follower. The third end of the parallel output circuit is connected with a reference voltage, the fourth end of the parallel output circuit outputs a fusion signal, the parallel output circuit is used for receiving conditioned signals output by multiple signal input conditioning circuits, and based on a one-way conduction characteristic, the conditioned signals are fused into one signal, and the fusion signal is the minimum value signal among the conditioned signals. The signal input conditioning circuit comprises multiple signal input conditioning sub-circuits.

2. The multi-sensor signal fusion circuit of claim 1, wherein, The first end of each signal input conditioning sub-circuit inputs one sensor signal, the second end of each signal input conditioning sub-circuit is connected with the first end of the parallel output circuit, and the third end of each signal input conditioning sub-circuit is connected with the second end of the operational amplifier isolation feedback circuit. Each signal input conditioning sub-circuit comprises a first operational amplifier and a first feedback branch.

3. The multi-sensor signal fusion circuit of claim 2, wherein, The non-inverting input end of the first operational amplifier is connected with the first end of the first feedback branch, and the output end of the first operational amplifier is connected with the first end of the parallel output circuit. The second end of the first feedback branch is connected with the second end of the operational amplifier isolation feedback circuit. Each signal input conditioning sub-circuit further comprises an input branch and a first grounding branch.

4. The multi-sensor signal fusion circuit of claim 3, wherein, The non-inverting input end of the first operational amplifier is grounded through the first grounding branch, and the non-inverting input end of the first operational amplifier is connected with one sensor signal through the input branch. The input branch and the first grounding branch each comprise at least one resistor.

5. The multi-sensor signal fusion circuit of claim 4, wherein, The operational amplifier isolation feedback circuit comprises a second operational amplifier and a second feedback branch.

6. The multi-sensor signal fusion circuit of claim 1, wherein, The non-inverting input end of the second operational amplifier is connected with the second end of the parallel output circuit, the non-inverting input end of the second operational amplifier is connected with the first end of the second feedback branch, the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is connected with the third end of the signal input conditioning circuit and the second end of the second feedback branch. The operational amplifier isolation feedback circuit further comprises a second grounding branch.

7. The multi-sensor signal fusion circuit of claim 6, wherein, The output end of the second operational amplifier is grounded through the second grounding branch. The second feedback branch and the second grounding branch each comprise at least one resistor.

8. The multi-sensor signal fusion circuit of claim 7, wherein, ​ 9. The multi-sensor signal fusion circuit of claim 2, wherein, The parallel output circuit comprises a plurality of unidirectional conduction switches and current-limiting resistors, wherein a first end of each of the unidirectional conduction switches is connected to a second end of one of the signal input conditioning sub-circuits, and a second end of each of the unidirectional conduction switches is connected to the reference voltage through the current-limiting resistor; a conduction direction of each of the unidirectional conduction switches is from the second end to the first end; the second ends of all the unidirectional conduction switches are connected to one point to form a third end of the parallel output circuit.

10. The multi-sensor signal fusion circuit of claim 9, wherein, The unidirectional conduction switches are diodes, wherein a cathode of each of the diodes is connected to a second end of one of the signal input conditioning sub-circuits, and an anode of each of the diodes is connected to the reference voltage through the current-limiting resistor.

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