Event response time measuring method based on momentum detection sensor

Abstract

The invention discloses an event response time measuring method based on a momentum detection sensor, which is a method for acquiring a particle collision position through the momentum detection sensor based on a piezoelectric effect in combination with different response times of a sensor array. The method is characterized in that the response time of a sensor array is measured by combining threshold detection and a counter, and the original position where bending waves occur is obtained according to the difference of the response time of the array, so that the position analysis of the momentum collision event of the tiny dust particles is completed.

Description

Technical Field

[0001] This invention belongs to the field of space environment detection technology, and in particular relates to a method for obtaining the location of a collision event by using threshold comparison and a timer to achieve the difference in event response time of different sensors for the purpose of detecting the momentum of space dust particles. Background Technology

[0002] Currently, momentum detection of space dust particles and location of collision events mainly rely on in-situ detection techniques based on impact ionization effects. This field has evolved from simple particle counting to the ability to accurately analyze particle mass, velocity, composition, and impact location.

[0003] Existing collision location determination technologies mainly follow three paths: First, there's the simultaneous analysis of chemical composition and location, representing the cutting edge. Take the IDEX instrument, soon to be deployed in the IMAP mission, as an example. Its core is a grid-like sensor array divided into multiple independent detection units. When ultra-high-speed interstellar dust impacts the panel, it instantly vaporizes, creating ion clouds. The instrument not only analyzes these ion clouds to obtain their chemical elemental and isotopic composition, but it can also directly determine the approximate area of ​​the impact based on which specific grid unit collected the signal. This technology can simultaneously acquire two crucial pieces of information about an impact event: its origin and its location.

[0004] Secondly, there is the indirect location method based on spacecraft structural health monitoring. This method has greater engineering application value. Instead of directly detecting the dust itself, it deploys a distributed sensor network (such as piezoelectric sensors) on the spacecraft surface or inside the structure. When space debris or dust impacts the structure at extremely high speeds, stress waves are generated. By analyzing the time difference of the stress wave propagating to different sensors, the precise coordinates of the impact point can be calculated, similar to earthquake location. This technology is developing into a key component of future spacecraft active protection systems.

[0005] Third is passive sampling and laboratory analysis. This is mainly used in short-duration sounding rocket missions, where dust samples are collected from specific directions using special mechanical structures (such as funnels) and then returned to Earth for high-precision analysis. Although this method cannot be performed in real time, it can provide the most detailed physicochemical information about the particles.

[0006] Despite continuous technological advancements, probes still face challenges such as adaptability to the extreme space environment and identification of weak signals. Future trends will focus on developing higher-resolution sensors, enabling multi-platform collaborative observation, and improving real-time intelligent data processing capabilities, thereby more accurately mapping the distribution of space dust and ensuring the on-orbit safety of spacecraft. Summary of the Invention

[0007] In view of this, the present invention provides a design for obtaining the response time of different channels for momentum detection of tiny dust particles in space. Based on the characteristic that the wave velocity of a flexural wave is related to its frequency, the resonant electrical signal generated by a piezoelectric ceramic, the threshold voltage comparison signal, and the timer built into the FPGA are used in combination to extract the response time of different channels.

[0008] An event response time measurement method based on a momentum detection sensor, the measurement system comprising a pure aluminum plate (1), a piezoelectric ceramic cylinder (3), an amplification, filtering and peak hold detection circuit (5), a threshold comparison circuit (6), an FPGA built-in timer (7), and an FPGA main control chip (8); there are at least three piezoelectric ceramic cylinders (3) arranged at different positions on the pure aluminum plate (1); the amplification, filtering and peak hold detection circuit (5), the threshold comparison circuit (6), and the piezoelectric ceramic cylinders (3) are integrated into the system. When dust particles collide with the pure aluminum plate (1), a momentum event is generated. The piezoelectric ceramic cylinders (3) at different positions respond to the momentum event. Each piezoelectric ceramic cylinder (3) outputs the induced signal to its corresponding amplification, filtering and peak holding detection circuit (5) for signal processing. The signal peak is then sent to its corresponding threshold comparison circuit (6). The threshold comparison circuit (6) compares the signal peak with the set threshold. When the signal peak is greater than the set threshold, a trigger signal is sent to the FPGA internal timer (7). The FPGA internal timer (7) counts each trigger signal it receives. The FPGA main control chip (8) obtains the response time of the piezoelectric ceramic cylinder (3) at different positions based on the timing of the FPGA internal timer (7); and then calculates the location where the momentum event occurs by combining the positional relationship of the piezoelectric ceramic cylinder (3) on the pure aluminum plate (1).

[0009] Preferably, a digital-to-analog converter (D / A) circuit (9) is used to convert the digital form of the set threshold generated by the FPGA main control chip (8) into an analog signal and send it to the threshold comparison circuit (6).

[0010] Preferably, it also includes a support structure (2) for fixing and supporting the pure aluminum plate (1).

[0011] Preferably, the amplification, filtering and peak hold detection circuit (5) amplifies and filters the induced signal.

[0012] Preferably, there are 5 piezoelectric ceramic cylinders (3), which are respectively arranged at the 4 corners and the center of the square pure aluminum plate (1) to form a surface array.

[0013] Preferably, the effective detection area of ​​the pure aluminum plate (1) is 100mm × 100mm.

[0014] Preferably, the signal transmission from the piezoelectric ceramic column (3) to the amplification, filtering and peak holding detection circuit (5) is achieved using a coaxial shielded cable (4).

[0015] Preferably, the FPGA main control chip (8) also monitors the output of the threshold comparison circuit (6) of each channel to enable the FPGA internal timer (7) to start and record the response time of each channel.

[0016] The present invention has the following beneficial effects: This invention relates to a method for measuring the event response time based on a momentum sensing sensor. By using a momentum sensing sensor based on the piezoelectric effect and combining it with the different response times of a sensor array, the method obtains the location of particle collisions. The method is characterized by using a combination of threshold detection and a counter to measure the response time of the sensor array. By analyzing the differences in the array's response times, the original location of the bending wave is obtained, thereby completing the location analysis of momentum collision events involving tiny dust particles. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the detection system of the present invention.

[0018] In the diagram: 1 - pure aluminum plate, 2 - support structure, 3 - piezoelectric ceramic cylinder, 4 - coaxial shielded wire, 5 - amplification, filtering and peak hold detection circuit, 6 - threshold comparison circuit, 7 - FPGA internal timer, 8 - FPGA main control chip, 9 - digital-to-analog converter (D / A) circuit.

[0019] Figures 2(a) and 2(b) are schematic diagrams of response times for events at different locations in embodiments of the present invention.

[0020] In the diagram: position 1 is the collision point of the dust particles, and position 2 is the transmission path of the bending wave to the PZT sensor. Detailed Implementation

[0021] This invention provides an event response time measurement method based on a momentum detection sensor. The sensitive area is a 100mm × 100mm dust particle detection zone. Five piezoelectric ceramic sensors are used to extract the particle collision positions across the entire sensitive area. A front-end signal processing circuit extracts the characteristic signals from the piezoelectric ceramic sensors, converting the physical quantity of momentum into peak voltage amplitude information, which is then compared with a system-set threshold voltage. If the threshold is exceeded, an event is considered to have occurred. For a dust particle momentum collision at a certain location, the response time for threshold comparison of each signal channel varies due to the different distances from the piezoelectric ceramic sensor. The event response time indicators for different channels can be obtained at the FPGA end. Based on the time difference and combined with a position analysis algorithm, the dust particle collision position can be obtained.

[0022] The detection system includes a sensor composed of a pure aluminum plate and a piezoelectric ceramic column, a shielded cable, an amplification, filtering and peak hold detection circuit, a threshold comparison circuit, and an FPGA built-in timer, etc. The position resolution of the detection system depends on the reference time of the FPGA's built-in timer. In this design, the propagation speed of the 200kHz bending wave in the aluminum plate is about 2000m / s, and the system requires a position resolution of less than 1mm. Therefore, the reference time of the FPGA's built-in timer is set to 100ns, and its position resolution can reach 2000m / s*100ns=0.2mm, thus meeting the system requirements. In the initial state, since no collision event occurs, the threshold comparison circuit of the detection system has no signal in each channel, and the output state of the threshold comparison circuit of each channel is low. The FPGA internal timer is in a waiting state to start. The start condition is that the threshold comparison circuit of any channel generates an event flag first, then the timer starts, and the event response time of the channel that generates the event flag first is recorded as 0, i.e., time T0. The timer stops when it overflows.

[0023] The response time of each path event in the detection system is recorded as the count value of the FPGA built-in timer at the moment when the threshold comparison circuit of each path generates the event flag. The product of this count value and the timer's base time of 100ns represents the relative time of each path response time with respect to the response time of the first path that generates the event flag, and also reflects the relative difference in the length of the curved wave transmission path.

[0024] Example: like Figure 1 As shown, the system composition of the sensor and interface design for detecting the momentum of tiny dust particles in space according to the present invention consists of a pure aluminum plate 1, a support structure 2, a piezoelectric ceramic cylinder 3, a coaxial shielded wire 4, an amplification, filtering and peak holding detection circuit 5, a threshold comparison circuit 6, an FPGA internal timer 7, an FPGA main control chip 8, and a digital-to-analog converter (D / A) circuit 9.

[0025] Figure 1 The system configuration and implementation steps are as follows: (1) Five piezoelectric ceramic columns 3 are distributed at the four corners and the center of the square pure aluminum plate 1, forming a surface array. The effective detection area of ​​the pure aluminum plate 1 is 100mm×100mm, which is the pasting position of the center point of the piezoelectric ceramic at the four corners. The support structure 2 achieves mechanical support and electrical isolation between the pure aluminum plate 1 and the structural shell. (2) The signal transmission from the piezoelectric ceramic column 3 to the amplification, filtering and peak holding detection circuit 5 is achieved using a coaxial shielded cable 4; (3) The output signals of the amplification, filtering and peak hold detection circuit 5 and the digital-to-analog converter (D / A) circuit 9 are both sent as input signals to the threshold comparison circuit 6 for amplitude comparison. The output signal of the amplification, filtering and peak hold detection circuit 5 is connected to the "positive" input terminal of the comparator, and the output signal of the digital-to-analog converter (D / A) circuit 9 is connected to the "negative" input terminal of the comparator. The threshold comparison circuit 6 is powered by a 3.3V single-ended power supply. (4) The FPGA built-in timer 7 is implemented by software using the logic unit of the FPGA main control chip 8. The FPGA main control chip 8 also monitors the output of the threshold comparison circuit 6 of each channel to realize the start of the FPGA built-in timer 7 and record the response time of each channel. Figure 2 shows a schematic diagram of the response time of dust particle collision events at different locations according to the present invention, which consists of dust particle collision location 1 and the transmission path 2 of the bending wave to the PZT sensor.

[0026] The implementation process of Figure 2 is as follows: (1) The dust particle collision location 1 is the location where the momentum event occurs on the pure aluminum plate; (2) The line connecting the dust particle collision position 1 to each PZT sensor is the transmission path 2 of the curved wave from the collision position to the PZT sensor. Since the curved wave is determined according to the material and the PZT resonant frequency, the wave speed is approximately 2000 m / s in this system. The response time of receiving the curved wave and generating the resonant signal varies with different line lengths. Therefore, the response order and time difference of each detection path have unique characteristic values ​​when the collision position is different. (3) The PZT detection path where the bending wave arrives first generates a signal and triggers a timer, so that the response time of the path is 0, i.e., time T0. (4) Each subsequent path generates a signal in sequence according to the length of the path, and records the running value of the FPGA internal timer as the response time (relative to T0). (5) Based on the response time sequence and relative time difference shown in Figure 2, the location information of dust particle collisions can be further calculated using the location analysis algorithm. Specifically, the location information of dust particle collisions can be calculated when there are 3 response signals. If there are fewer than 3 response signals, it is considered to be due to noise.

[0027] The specific embodiments described above only illustrate the design principles of the present invention. The shapes and names of the components in this description may differ and are not limited. Therefore, those skilled in the art can modify or make equivalent substitutions to the technical solutions described in the foregoing embodiments; and these modifications and substitutions do not depart from the inventive spirit and technical solutions of the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A method of measuring the response time of an event based on a momentum detection sensor, characterized in that, The measurement system comprises a pure aluminum aluminum plate (1), a piezoelectric ceramic cylinder (3), an amplification filtering and peak holding detection circuit (5), a threshold comparison circuit (6), an FPGA internal configuration timer (7), and an FPGA master control chip (8); the piezoelectric ceramic cylinder (3) is arranged at different positions of the pure aluminum aluminum plate (1). When dust particles collide with the pure aluminum aluminum plate (1), momentum events are generated, and the piezoelectric ceramic cylinders (3) at different positions respond to the momentum events; each piezoelectric ceramic cylinder (3) outputs an induced signal to the corresponding amplification filtering and peak holding detection circuit (5) for signal processing, and then sends the signal peak to the corresponding threshold comparison circuit (6); the threshold comparison circuit (6) compares the signal peak with the set threshold value, and when the signal peak is greater than the set threshold value, a trigger signal is sent to the FPGA internal configuration timer (7), and the FPGA internal configuration timer (7) counts each trigger signal received. The FPGA master control chip (8) obtains the response time of the piezoelectric ceramic cylinder (3) at different positions in the momentum event according to the counting of the FPGA internal configuration timer (7); and then, in combination with the positional relationship of the piezoelectric ceramic cylinder (3) on the pure aluminum aluminum plate (1), the occurrence position of the momentum event is calculated. 2.The momentum-probe-sensor-based event response time measurement method of claim 1, wherein, A digital-to-analog conversion D / A circuit (9) is used to convert the digital form of the set threshold value generated by the FPGA master control chip (8) into an analog signal, which is sent to the threshold comparison circuit (6). 3.The momentum-probe-sensor-based event response time measurement method of claim 1, wherein, A support structure (2) is further included for fixing and supporting the pure aluminum aluminum plate (1). 4.The momentum-probe-sensor-based event response time measurement method of claim 1, wherein, The amplification filtering and peak holding detection circuit (5) performs signal amplification and filtering processing on the induced signal. 5.The momentum-probe-sensor-based event response time measurement method of claim 1, wherein, The piezoelectric ceramic cylinder (3) has five piezoelectric ceramic cylinders arranged at the four corners and the center of the square pure aluminum aluminum plate (1), forming a surface array. 6.The momentum-probe-sensor-based event response time measurement method of claim 1, wherein, The effective detection area of the pure aluminum aluminum plate (1) is 100mm×100mm. 7.The momentum-probe-sensor-based event response time measurement method of claim 1, wherein, The signal transmission from the piezoelectric ceramic cylinder (3) to the amplification filtering and peak holding detection circuit (5) is realized by using a coaxial shielded wire 4. 8.The momentum-probe-sensor-based event response time measurement method of claim 1, wherein, The FPGA master control chip (8) further monitors the output of each channel threshold comparison circuit (6) to start the FPGA internal configuration timer (7) and record the response time of each channel.

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