Embedded traffic overload control integrated machine system based on ARM architecture

Abstract

The application discloses an embedded traffic overload control integrated machine system based on an ARM architecture and relates to the field of traffic overload control.The system comprises a clock reference module, which is integrated in an ARM processor and is used for generating a reference clock signal and distributing the reference clock signal to each functional module in the system; and a sensing module, which is used for accessing an analog voltage signal output by a road weighing sensor, taking a rising edge of the reference clock signal as a starting trigger for analog-digital conversion, and converting the analog voltage signal into a weight digital quantity carrying a time label; the application makes the weight and the image time label homologous through a unified clock reference, combines temperature compensation and vehicle speed correction with row exposure, accurately associates with a space threshold, suppresses misplacement, writes each storage block in turns during storage to disperse the number of erasing and writing times, and adds a check value associated with a previous record to each record, so that the data can be self-checked and prevented from being changed, the subsequent transmission is not lost after communication interruption, and no complex hardware is added, which is beneficial to long-term stable operation.

Description

Technical Field

[0001] This invention relates to the field of traffic overload control technology, specifically to an embedded integrated traffic overload control system based on ARM architecture. Background Technology

[0002] Overloaded and oversized freight vehicles on highways directly threaten infrastructure safety and traffic order. Traditional methods of controlling overloading rely on fixed inspection stations and low-speed weighing equipment, which are inefficient and disruptive to traffic. With the promotion of non-site enforcement models, technologies such as dynamic weighing and license plate recognition are rapidly integrating. ARM architecture processors, with their low power consumption, high integration, and industrial-grade environmental adaptability, have been widely deployed in the field of traffic monitoring.

[0003] The invention patent application with application number 201610073884.2 discloses a source technology-based data acquisition system and method for controlling overloaded vehicles based on intelligent transportation. This application aims to solve the problems of low efficiency and easy conflict in the traditional source control mode. By integrating multiple detection components and special circuit topology, it provides an automated source control data acquisition solution.

[0004] However, existing solutions of this kind mostly consist of independent devices such as weighing sensors, cameras and industrial control computers connected through an external bus. Each module has an independent clock, making it difficult to accurately align dynamic weighing data with vehicle images on the timeline, resulting in significant matching errors in high-speed driving scenarios.

[0005] Therefore, it is necessary to build a hardware-level unified timestamp in the ARM all-in-one machine to achieve synchronous acquisition of multi-source data. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an embedded traffic control system based on ARM architecture, which can effectively solve the problems of the existing technology.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions;

[0008] This invention discloses an embedded traffic control system based on ARM architecture, comprising:

[0009] The system comprises a clock reference module, integrated within the ARM processor, which generates a reference clock signal and distributes it to various functional modules. A sensing module receives the analog voltage signal output from the road weighing sensor and uses the rising edge of the reference clock signal as the trigger for analog-to-digital conversion, converting the analog voltage signal into a digital weight value carrying a time tag. An acquisition module connects to a camera assembly and uses the rising edge of the reference clock signal as the trigger for image frame exposure, ensuring the exposed image frame carries a time tag originating from the digital weight value. An association module acquires the digital weight value and its time tag, as well as the image frame and its time tag, binding the digital weight value and the image frame as a structured data object of the same vehicle using the time tag as a unique key. A storage module receives the structured data object and writes it to an embedded non-volatile memory according to the time tag sequence. A communication module outputs the structured data object to an external platform according to the time tag sequence.

[0010] The clock reference module is connected to the sensing module and the acquisition module via an on-chip bus to establish a clock signal connection. The sensing module, acquisition module, association module, storage module and communication module are connected to each other via an on-chip data bus. The sensing module is connected to the road weighing sensor via an analog-to-digital conversion interface. The acquisition module is connected to the camera component via a serial interface.

[0011] The storage module establishes a connection with the embedded non-volatile memory through a storage interface, and the communication module establishes a connection with the external platform through a network interface.

[0012] Furthermore, the clock reference module includes a phase-locked loop, a clock distribution network, and a timestamp generator integrated within the ARM processor;

[0013] The phase-locked loop multiplies the external crystal oscillator frequency to the reference frequency. The clock distribution network transmits the generated reference clock signal to the sensing module, acquisition module, association module, storage module and communication module respectively via equal-length traces;

[0014] The timestamp generator includes a counter that increments on the rising edge of the reference clock signal. The count value of the counter, together with the start-up second count, constitutes the timestamp. The timestamp is a 64-bit unsigned integer, with the high 32 bits representing the number of seconds since system startup and the low 32 bits representing the reference clock cycle count value within the current second.

[0015] Furthermore, the clock reference module reads the lower 32-bit count values ​​of the time tags latched by the sensing module and the acquisition module on the same reference clock signal edge. If the absolute value of the difference between the two exceeds the preset out-of-synchronization threshold number of times consecutively, the clock is determined to be out of sync, an alarm signal is generated, and the clock distribution network is triggered to realign and distribute the clock.

[0016] Furthermore, the sensing module includes an instrumentation amplifier, an anti-aliasing filter, an analog-to-digital converter, a temperature sensor, and a compensation calculation unit;

[0017] The instrumentation amplifier receives the analog voltage signal output from the road surface weighing sensor. Its gain is set according to the ratio of the full-scale input range of the analog-to-digital converter to the maximum output voltage amplitude of the road surface weighing sensor under rated load, so that the output signal amplitude matches the input dynamic range of the analog-to-digital converter. The -3dB cutoff frequency of the anti-aliasing filter is set to [value missing]. ,in The reference frequency generated by the clock reference module, where k is a preset multiple greater than 2, is used to suppress frequencies higher than [the specified frequency]. Noise components are superimposed into the baseband;

[0018] The temperature sensor is thermally coupled to the road surface weighing sensor, acquiring the sensor temperature T in real time. The analog-to-digital converter initiates conversion on the rising edge of the reference clock signal, outputting the raw weight digital value. The compensation calculation unit stores the original weight digital value from the previous sample and assigns a corresponding time tag. and its time label, and based on the current sample The final weight is calculated using the difference Δt between the current time stamp and the previous sampling time stamp, and the temperature T, according to the following formula:

[0019] ;

[0020] In the formula: For calibrating the reference temperature; It is a first-order temperature coefficient; It is a second-order temperature coefficient; For dynamic correction of amplitude coefficient; This is the strain rate scaling factor; It is a time interval in seconds, calculated by dividing the difference between the time stamps of two samples by 1 / 2. It can be concluded that;

[0021] The final The time stamp of the sampling time constitutes the weighted digital quantity carrying the time stamp.

[0022] Furthermore, the camera component is a line exposure type image sensor;

[0023] The acquisition module records the time stamp of its first line of exposure trigger time. and the pre-defined row scan cycle And the line delay compensation value δ, where , Both δ and δ are expressed in terms of the number of reference clock cycles;

[0024] The acquisition module uses the time tag difference between two adjacent weight values ​​provided by the sensing module and the pre-stored length along the driving direction of the road surface weighing sensor. Calculate the vehicle's speed v;

[0025] The acquisition module performs motion compensation on the exposure time stamp of each row based on the following formula to obtain the corrected row time stamp:

[0026] ;

[0027] In the formula: For row index; The preset image sensor center row index; This represents the total number of rows in the image sensor. The reference frequency generated by the clock reference module;

[0028] The acquisition module uses the corrected row time tag sequence as the time tag carried by the image frame.

[0029] Furthermore, the association module obtains the time stamp of the weight digital quantity. and the row time tag sequence of the image frame And calculate the spatial deviation distance. ;

[0030] Will satisfy The row range is marked as a valid associated row. If there is more than one valid associated row, select the one that makes the association valid. The smallest row, binds the image of that row region to the weight digital value as a structured data object of the same vehicle; This is the preset spatial tolerance threshold.

[0031] Furthermore, the embedded non-volatile memory is divided into N physical storage blocks of equal capacity, and the storage module includes a write sequence counter and an address mapping table;

[0032] The write sequence number counter is set to zero during system initialization, and its value is incremented by one each time a structured data object is written.

[0033] The address mapping table takes the current write sequence number count as input, takes the modulo of the count value with the total number of physical storage blocks N to obtain the remainder r, and then uses r as the input index to look up the table from the preset N-ary replacement table to output the target physical block address;

[0034] The preset N-ary permutation table is a set A permutation of the given information, wherein the difference between the output addresses corresponding to any adjacent indices in the permutation is not 1, and the permutation table is generated and fixed in the address mapping table when the system is manufactured.

[0035] When the value of the write sequence counter reaches its maximum value, the next write operation resets it to zero and increments it again, so that in consecutive write cycles, the number of erases and writes of each physical block tends to be balanced with the increase of the total number of writes.

[0036] The storage module writes structured data objects into the target physical block output by the address mapping table according to the time stamp.

[0037] Furthermore, during the operation of the storage module, before writing the structured data objects to the physical blocks, a chained digest value is generated for each structured data object in chronological order based on its timestamp:

[0038] ;

[0039] In the formula: Hash is a preset cryptographic hash function; The timestamp of the i-th structured data object; Weight (numerical quantity); The image frame is a thumbnail obtained by downsampling. The double vertical line symbol indicates the concatenation of binary data.

[0040] The storage module stores the chained digest value The data is additionally stored in the corresponding structured data object record.

[0041] Furthermore, the communication module has a built-in sending queue and acknowledgment management unit;

[0042] The communication module sends the structured data objects to the external platform one by one in time tag order, and waits for the external platform to return confirmation information;

[0043] The confirmation management unit records the latest confirmed timestamp. When communication is interrupted and resumed, it reads the next structured data object with a later confirmation timestamp from the storage module to start the transmission.

[0044] Compared with the known prior art, the technical solution provided by this invention has the following beneficial effects:

[0045] This invention distributes a reference clock signal to each functional component, enabling weight acquisition and image exposure to share the same time stamp. It also introduces temperature drift compensation and dynamic strain rate correction at the sensing end, while performing motion compensation based on vehicle speed at the image end. Finally, it uses a spatial deviation threshold to accurately correlate weight with the image area. This system can effectively suppress data misalignment and measurement deviation caused by clock skew, temperature changes, vehicle speed differences, and rolling exposure distortion, thereby improving the reliability of overload control data in terms of temporal consistency and spatial correspondence.

[0046] Based on this, a wear leveling strategy using a substitution table mapping is adopted during storage to extend the service life of non-volatile media. The sequential appending of chained digest values ​​provides a self-verifiable anti-tampering basis for post-audit. The transmission resumption mechanism after communication interruption avoids repeated collection or data loss. The above measures together ensure the data integrity and transmission continuity of the system during long-term field operation. Moreover, the overall solution is implemented based on the internal resources of the ARM processor without adding extra complex hardware, which helps to maintain the economy and deployment convenience of embedded devices. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0048] Figure 1 This is a schematic diagram of an embedded traffic control system based on the ARM architecture.

[0049] Figure 2 This is a schematic diagram of the timing of reference clock synchronization distribution and line exposure motion compensation in this invention;

[0050] Figure 3 This is a flowchart illustrating the vehicle data association, tamper-proof chained storage, and communication continuation process in this invention. Detailed Implementation

[0051] 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] The present invention will be further described below with reference to embodiments.

[0053] Example:

[0054] This embodiment of the embedded traffic control system based on ARM architecture, such as... Figure 1 As shown, it includes:

[0055] The clock reference module, integrated inside the ARM processor, is used to generate a reference clock signal and distribute the reference clock signal down to various functional modules in the system;

[0056] The clock reference module includes a phase-locked loop, a clock distribution network, and a timestamp generator integrated within the ARM processor;

[0057] The phase-locked loop multiplies the external crystal oscillator frequency to the reference frequency. The clock distribution network transmits the generated reference clock signal to the sensing module, acquisition module, correlation module, storage module, and communication module via equal-length traces.

[0058] The timestamp generator contains a counter that increments on the rising edge of the reference clock signal. The counter's count value, together with the start-up second count, constitutes a timestamp. The timestamp is a 64-bit unsigned integer, with the high 32 bits representing the number of seconds since system startup and the low 32 bits representing the reference clock cycle count value within the current second.

[0059] The clock reference module reads the lower 32-bit count values ​​of the time tags latched by the sensing module and the acquisition module on the edge of the same reference clock signal. If the absolute value of the difference between the two exceeds the preset out-of-synchronization threshold for a number of consecutive times, the clock is determined to be out of sync, an alarm signal is generated, and the clock distribution network is triggered to realign and distribute the clock.

[0060] It needs to be further clarified that the aforementioned number of determinations is not general, but refers to a fixed threshold parameter that can be configured by the system, denoted as... ;

[0061] The specific value of this parameter is loaded into the configuration register of the clock reference module during the system initialization phase, and its value is determined according to the following engineering principles:

[0062] Because momentary congestion of the on-chip bus or short-term frequency pulling effect of the external crystal oscillator can cause random deviations of no more than two reference clock cycles in a single sampling time when the sensing module and the acquisition module latch their respective time tags, therefore A value greater than 1 is required to eliminate interference from this type of physical noise. Based on the measured data of the short-term frequency stability of the crystal oscillator of the industrial-grade ARM processor used in this system at temperatures ranging from -40℃ to 85℃, Setting it to 3 times can achieve the optimal balance between false alarm rate and missed alarm rate;

[0063] Meanwhile, this parameter is saved in plaintext in the system's factory configuration file. On-site maintenance personnel can read the current setting value through the maintenance serial port and adjust it according to actual operating conditions (such as the electromagnetic environment strength of the installation site). Manual tuning is performed within the range of 2 to 5. The tuned value is written into a non-volatile register and takes effect automatically after the system restarts, without requiring modification of the firmware source code.

[0064] The preset out-of-step threshold is determined based on the maximum transmission delay difference of each equal-length trace in the clock distribution network, and its value is rounded up to the number of reference clock cycles corresponding to the maximum transmission delay difference.

[0065] The sensing module is used to receive the analog voltage signal output by the road weighing sensor. The rising edge of the reference clock signal is used as the start trigger for analog-to-digital conversion, converting the analog voltage signal into a digital weight carrying a time tag.

[0066] The sensing module includes an instrumentation amplifier, an anti-aliasing filter, an analog-to-digital converter, a temperature sensor, and a compensation and processing unit;

[0067] The instrumentation amplifier receives the analog voltage signal output from the road surface weighing sensor. Its gain is set according to the ratio of the full-scale input range of the analog-to-digital converter (ADC) to the maximum output voltage amplitude of the road surface weighing sensor under rated load, so that the output signal amplitude matches the input dynamic range of the ADC. The -3dB cutoff frequency of the anti-aliasing filter is set to [value missing]. ,in The reference frequency generated by the clock reference module, where k is a preset multiple greater than 2, used to suppress frequencies higher than [the specified frequency]. Noise components are superimposed into the baseband;

[0068] The temperature sensor is thermally coupled to the road surface weighing sensor to acquire the sensor temperature T in real time. The analog-to-digital converter starts the conversion on the rising edge of the reference clock signal and outputs the raw weight digital value. It also assigns a corresponding time tag and compensates the computation unit for storing the original weight digital value of the previous sample. Its time stamp (regarding the initial state during the first sampling, the compensation calculation unit executes the following initialization process after power-on reset: the weight of the previous sample...) Initialize to the actual raw value of the current sample. The difference Δt between the previous and current sampling time stamps is initialized to a preset typical time interval value (this value is twice the design response time of the road weighing sensor, provided by the sensor's factory parameters), and the hyperbolic tangent function output in the dynamic correction term is directly set to zero. Through this initialization scheme, the first weight data output by the system is statically compensated only by the temperature drift exponent term, without introducing any dynamic correction based on strain rate. When the second and third samples arrive, the compensation calculation unit naturally obtains the true preceding value and the measured time difference, and the dynamic correction function seamlessly enters normal working state. This process is completed instantaneously in the first AD conversion completion interrupt after firmware startup (without affecting the subsequent real-time data processing pipeline), and is based on the current sampling... The final weight is calculated using the difference Δt between the current time stamp and the previous sampling time stamp, and the temperature T, according to the following formula:

[0069] ;

[0070] In the formula: For calibrating the reference temperature; It is a first-order temperature coefficient; It is a second-order temperature coefficient; For dynamic correction of amplitude coefficient; This is the strain rate scaling factor; It is a time interval in seconds, calculated by dividing the difference between the time stamps of two samples by 1 / 2. It can be concluded that;

[0071] The above formula uses an exponential term to fit the first and second order temperature drift of the sensor, and a hyperbolic tangent function to correct the dynamic weighing error of the vehicle's speed change. By calibrating and fitting a complete set of correction parameters through actual measurement, static temperature drift and dynamic load deviation are compensated simultaneously at one time. This changes the traditional practice of separately correcting the two types of errors in weighing equipment and improves weighing accuracy.

[0072] The final The time stamp of its sampling time constitutes the weighted digital quantity carrying the time stamp;

[0073] in, , Determined in the following ways:

[0074] Place the road surface weighing sensor in a temperature-controlled environment, and under zero load, allow the temperature to vary within a preset operating temperature range, recording the original weight values ​​at different temperature points. , and make The parameters are obtained by approximating the zero-drift curve caused by temperature.

[0075] β and γ are determined in the following way: At a given temperature, vehicles of known calibrated weight are driven across road weighing sensors at different speeds, and the data generated during the weighing process are recorded. , and Δt sequence, and make The parameters are obtained by fitting the data with the objective of minimizing the mean square error of the known calibration weight; Δt is obtained by dividing the difference between the time stamps of the two samples by... It can be concluded that;

[0076] It should be noted that the Δt involved in the above calculations must be constrained to prevent system shutdown due to division by zero anomalies. Specifically:

[0077] Before the compensation unit performs the division operation, it first compares the difference between the current sampling time tag and the previous sampling time tag; if the difference is less than 2 reference clock cycles, it forces Δt to be assigned the number of seconds corresponding to 2 reference clock cycles (i.e., 2 / At the same time, the dynamic correction term for this weight data is set to 0, and only the temperature drift index term is retained. Calculation;

[0078] If the difference is not less than 2 reference clock cycles, then the actual time difference is directly used in the calculation. The selection of this lower limit value of 2 is based on the following:

[0079] Two valid samples cannot occur completely simultaneously in physical terms. Any difference of less than 2 clock cycles is caused by on-chip bus competition or trigger signal glitches. Saturating these glitches ensures the absolute stability of the system operation without affecting the dynamic correction accuracy at normal vehicle speed.

[0080] The acquisition module is used to connect to the camera component and use the rising edge of the reference clock signal as the start trigger for image frame exposure, so that the image frame after exposure carries a time stamp that is of the same origin as the digital value of weight.

[0081] The camera component is a line exposure type image sensor;

[0082] It needs to be further clarified that the system does not initiate a new image exposure frame at every rising edge of the reference clock; the actual execution of frame exposure initiation is controlled by the triggering and discrimination logic inside the acquisition module.

[0083] The triggering logic uses the real-time weight digital sequence output by the sensor module as the basis for judgment. Specifically, the acquisition module continuously reads three weight digital sample values. If all three exceed the preset vehicle weighing weight threshold (this threshold is set during system installation based on the zero-drift measured value of the road weighing sensor, usually 2% of the rated range), it is determined that a vehicle has entered the weighing area. At this time, the triggering logic immediately sends a frame start enable signal to the frame synchronization control unit of the acquisition module. The acquisition module latches the time stamp of the first exposure trigger moment at the rising edge of the first reference clock after receiving the enable signal. The entire frame is exposed line by line according to the scanning cycle;

[0084] After the current frame exposure and subsequent associated storage operations are completed, the frame synchronization control unit automatically clears the enable signal, and the acquisition module returns to the ready-to-trigger state. Only when the next round of weight digital sequence meets the above judgment conditions can the acquisition of the next frame image be started.

[0085] For periods when the triggering conditions are not met, the acquisition module does not apply any exposure start operation to the camera component, thereby avoiding the system from continuously generating invalid image data during periods when there are no vehicles, reducing the frequency of erasing and rewriting the storage medium and reducing the invalid transmission burden on the communication module.

[0086] The acquisition module records the time stamp of the first exposure trigger moment. and the pre-defined row scan cycle And the line delay compensation value δ, where , Both δ and δ are expressed in terms of the number of reference clock cycles;

[0087] The data acquisition module uses the time tag difference between two consecutive weight readings provided by the sensor module and the pre-stored length along the driving direction from the road surface weighing sensor. Calculate the vehicle's speed v;

[0088] To accurately calculate the vehicle speed as it passes through the weighing area, variables are introduced. This variable is defined as the difference between the start and end times of the effective weighing time window of the same vehicle axle group through the road weighing sensor, rather than the inherent difference between two adjacent fixed clock sampling periods.

[0089] The compensation calculation unit inside the sensing module incorporates a lightweight state machine in the real-time sampling stream: when three consecutive weight samples exceed the preset vehicle weighing threshold, the first over-threshold sampling moment is latched as the window start time tag. ;

[0090] Subsequently, the weight sequence is continuously monitored. When three consecutive weight samples are all below the threshold, the last sample time that falls below the threshold is latched as the end time label of the window. ;

[0091] at this time Pick - The true difference (in reference clock cycles) varies significantly with the actual speed of the vehicle, with the vehicle speed calculated as follows: Calculated;

[0092] If the weight signal is above the threshold for an extended period due to extremely low vehicle speed, or if the number of valid sampling points is less than three due to extremely high vehicle speed, making it impossible to reliably determine the start and end times, the sensing module will abandon this autonomous speed measurement and set ν to the default reference vehicle speed value that was solidified in the non-volatile memory after multi-point calibration by the on-site radar speedometer during system installation. The metadata area of ​​this data will be marked with "vehicle speed is nominal value". This default value serves as a final guarantee to ensure that the line exposure compensation formula has an effective vehicle speed factor that can be substituted under any working condition, avoiding the interruption of the entire data processing pipeline due to speed measurement failure.

[0093] The acquisition module performs motion compensation on the exposure time stamps of each row based on the following formula to obtain the corrected row time stamps:

[0094] ;

[0095] In the formula: For row index; The preset image sensor center row index; This represents the total number of rows in the image sensor. The reference frequency generated by the clock reference module;

[0096] The above formula completes the basic timing calibration by superimposing the line period and hardware delay at the exposure trigger time. It calculates the time offset caused by vehicle displacement by combining the scale size, vehicle speed and sensor parameters, and compensates for the line exposure timing difference line by line. Unlike the unified timestamp scheme for the whole frame, it effectively eliminates the timing misalignment of images and text caused by vehicle movement.

[0097] The acquisition module uses the corrected row time label sequence as the time label carried by the image frame;

[0098] Among them, row scan cycle The calibration method is as follows: Under the drive of the reference clock signal, the line synchronization signal output by the image sensor is clocked for multiple consecutive line cycles, and the average value of the count is taken as the calibration result. The calibration method for the line delay compensation value δ is as follows: Under no ambient light conditions, use a point light source with a pulse width less than one reference clock cycle to simultaneously illuminate each line of the image sensor, measure the time interval from the transition of the line exposure trigger signal to the output of the pixel of that line reaching a preset threshold, and convert this time interval into the number of reference clock cycles to obtain δ.

[0099] Preset image sensor center row index The row number is either the row number corresponding to the geometric center of the pixel array of the image sensor, or the row number corresponding to the intersection of the optical axis of the camera component and the photosensitive surface of the image sensor.

[0100] The association module is used to obtain the weight digital quantity and its time tag, image frame and its time tag, and bind the weight digital quantity and image frame as the same vehicle structured data object with the time tag as the unique key value;

[0101] At the implementation level, the road weighing sensor will generate a series of sequential weight values ​​during the continuous passage of multi-axle vehicles, rather than a single isolated value. Therefore, the system must add an axle group buffer and a vehicle separation determination mechanism before the associated operation.

[0102] Specifically, the sensing module completes each instantaneous weight reading. After temperature and dynamic compensation, the data is not directly pushed outward, but temporarily stored in the axle group buffer. Simultaneously, an independently running timer is started. When the continuously received weight data in the buffer falls below the preset lower scale threshold (this threshold is the same as the aforementioned upper scale threshold, both being 2% of the rated capacity), and the low-level duration exceeds the preset minimum axle interval time (this time is determined to be 400 milliseconds based on the wheelbase and minimum passing speed of common freight vehicles on site, and is stored as a system configuration parameter in non-volatile memory), the buffer state machine determines that all axles of the current vehicle have passed. At this time, the buffer arithmetically sums all the instantaneous weight data corresponding to the vehicle to obtain the vehicle's total weight. (where m is the total number of axles of the vehicle), and at the same time, take the timestamp of the first weight value in the buffer as the timestamp of the vehicle. ;

[0103] After completing the above accumulation, the system will... Together They are submitted together to the associated module; if the buffer receives a new valid weight sample value within the minimum interval between axles, it is added to the buffer of the same vehicle and the accumulation continues until the separation condition is met.

[0104] The axle group buffer is forcibly cleared every time the system is powered on and reset. Through the axle group accumulation and vehicle separation logic, each weight data received by the association module is the complete total vehicle weight. After binding it with the whole vehicle image by time tag, the output structured data object truly has the one-to-one correspondence between "vehicle-weight-image" required for overload control enforcement, thus meeting the evidence chain requirements of off-site enforcement.

[0105] The associated module obtains the time stamp of the weight digital quantity. and the line time tag sequence of image frames And calculate the spatial deviation distance. ;

[0106] This formula converts the time difference between the image row and the weighing data into a time length, combines the vehicle speed into the longitudinal offset distance of the vehicle, quantifies the positional deviation of the image and text, no longer relies on rough matching of fuzzy time intervals, and uses quantifiable spatial distance as the criterion for vehicle data binding.

[0107] Will satisfy The row range is marked as a valid associated row. If there is more than one valid associated row, select the one that makes the association valid. The smallest row binds the image of that row region to the weight digital value as a structured data object of the same vehicle; The preset spatial tolerance threshold;

[0108] It should be added that, if the current weight is a digital time stamp... After traversing the entire time-stamp sequence of the image frames, no row was found that met the requirements. If so, the association module does not discard the weight data, but instead switches to a predefined abnormal association processing branch;

[0109] This branch performs the following operations:

[0110] Selecting from the entire frame image The row region with the smallest absolute value is written into the metadata area of ​​the structured data object as an additional tag field, and the effective confidence level of the data is marked as low confidence level pending review.

[0111] The storage and communication modules continue to store and upload this type of low-confidence data as usual. However, after receiving the tag, the external platform can provide a clear visual reminder on the display interface. The back-end manual reviewers will then make a secondary comparison between the original image and the weighing waveform to confirm whether the association is correct.

[0112] This mechanism ensures that even in extreme scenarios where the correlation conditions are not fully met, the system can still output traceable original evidence packages without implicitly discarding weight or image information due to the lack of matching rows, thus maintaining the integrity and verifiability of on-site data at the level of legal evidence collection.

[0113] in, , The longitudinal field of view height of the camera component at the road surface is calculated during system installation by measuring the installation height, pitch angle, and lens field of view of the camera component, and is pre-stored in the associated module;

[0114] Longitudinal field of view height Determined according to the following trigonometric geometric relationships:

[0115] Let h be the vertical height of the optical center of the camera lens from the road surface, θ be the pitch angle between the lens optical axis and the road surface, and the field of view of the lens in the vertical direction be... Then the longitudinal field of view height at the road surface ;

[0116] Based on this, the spatial tolerance threshold It is composed of two parts: the physical half-length of the weighing platform and the vertical resolution of a single row of pixels. ,in The physical meaning of is the actual physical height covered by a single pixel row in the longitudinal direction of the road surface. This value serves as a margin for spatial matching and is used to absorb positioning fluctuations caused by lateral vehicle offset and installation errors.

[0117] The above method integrates the half-length of the weighing platform and the vertical field of view distance of a single row of pixels in the camera to determine the matching tolerance threshold, taking into account both the physical boundary of weighing and the coverage of the camera image. It replaces the fixed threshold setting and can adaptively adjust the effective matching range according to the equipment installation and lens parameters.

[0118] The storage module is used to receive structured data objects and write them to the embedded non-volatile memory according to the time stamp.

[0119] The embedded non-volatile memory is divided into N physical memory blocks of equal capacity. The memory module contains a write sequence counter and an address mapping table.

[0120] The write sequence number counter is set to zero during system initialization, and its value is incremented by one each time a structured data object is written.

[0121] The address mapping table takes the current write sequence number count as input, takes the modulo of the count value with the total number of physical storage blocks N to get the remainder r, and then uses r as the input index to look up the table from the preset N-ary replacement table to output the target physical block address;

[0122] The pre-defined N-ary permutation table is a set A permutation of the system, where the difference between the output addresses corresponding to any adjacent indices in the permutation is not 1. The permutation table is generated and fixed in the address mapping table when the system is manufactured.

[0123] When the write sequence counter reaches its maximum value, the next write operation resets it to zero and increments it again, so that the number of erases and writes to each physical block tends to be balanced as the total number of writes increases in consecutive write cycles.

[0124] The storage module writes structured data objects into the target physical block output by the address mapping table according to the time stamp.

[0125] During the storage module's operation phase, before writing structured data objects to physical blocks, chained digest values ​​are generated for each structured data object in time-stamped order:

[0126] ;

[0127] In the formula: Hash is a preset cryptographic hash function; The timestamp of the i-th structured data object; Weight (numerical quantity); The image frame is a thumbnail obtained by downsampling. The double vertical line symbol indicates the concatenation of binary data.

[0128] The above formula concatenates the preceding digest, timestamp, weight, and thumbnail, and then generates the data digest of this line through cryptographic hashing, forming a one-way continuous verification chain. Relying on hardware encryption to accelerate the operation, unlike single independent verification, any data tampering will destroy the entire chain, realizing full data tamper-proof traceability.

[0129] The storage module will store the chained digest values. The data is additionally stored in the corresponding structured data object record;

[0130] in, This is the initial digest value written to the embedded non-volatile memory when the system leaves the factory;

[0131] The preset cryptographic hash function uses the SHA-256 algorithm or the SM3 cryptographic hash algorithm, which is executed by the secure hash hardware accelerator integrated in the ARM processor, and outputs a hash value of fixed length 256 bits.

[0132] The generation method is as follows:

[0133] At the factory, the system's unique device serial number, current timestamp, and random number are concatenated, and then processed by a preset cryptographic hash function to obtain the hash value, which is then written to a dedicated protected area of ​​the embedded non-volatile memory; chained digest value The timestamps, weights, and thumbnails of the structured data objects are stored in the same physical storage block, forming a data path from... Beginning, through A tamper-proof chain of sequential links;

[0134] The communication module outputs structured data objects to external platforms according to the time sequence of time tags;

[0135] The communication module has a built-in send queue and acknowledgment management unit;

[0136] The communication module sends structured data objects one by one to the external platform in time-stamped order, and waits for the external platform to return confirmation information;

[0137] The management unit confirms the latest confirmed timestamp. When communication is interrupted and resumed, it reads the next structured data object with a later confirmation timestamp from the storage module to start the transmission.

[0138] The clock reference module establishes a clock signal connection with the sensing module and the acquisition module through the on-chip bus. The sensing module, acquisition module, correlation module, storage module and communication module establish a data connection through the on-chip data bus. The sensing module establishes an electrical connection with the road weighing sensor through the analog-to-digital conversion interface. The acquisition module establishes a connection with the camera component through the serial interface.

[0139] The storage module establishes a connection with the embedded non-volatile memory through the storage interface, and the communication module establishes a connection with the external platform through the network interface.

[0140] In this embodiment, after the system is powered on, the clock reference module inside the ARM processor starts first. The phase-locked loop multiplies the external crystal oscillator to the reference frequency. The clock distribution network distributes the reference clock signal synchronously to each functional module through equal-length traces. At the same time, the counter in the timestamp generator increments with each rising edge, laying a unified time base for all subsequent data. This design ensures the homogeneity of the two heterogeneous data types, weight and image, in terms of time base from the source, avoiding systematic deviations introduced by clock asynchrony during later alignment.

[0141] The sensing module continuously monitors the analog voltage signal output by the road weighing sensor. Each rising edge of the reference clock triggers the analog-to-digital converter to start sampling once. The converted raw weight digital value, along with the currently latched time tag, is sent to the compensation calculation unit. This unit combines the weight value of the previous sample, the time interval between the two samples, and the real-time temperature to calculate the final weight digital value according to the preset temperature compensation and dynamic correction formulas. The temperature compensation coefficient is obtained in advance in the temperature control box by fitting the zero-load drift curve, while the dynamic correction coefficient is optimized based on the calibrated vehicle weighing data at different vehicle speeds, so that a relatively stable weight value can be output in a wide temperature range and dynamic weighing scenarios.

[0142] The acquisition module synchronously drives the camera component to expose image frames. The rising edge of the reference clock is used as the trigger for line exposure. Since the vehicle is in motion, the actual exposure time of each row of pixels is different. The module calculates the current vehicle speed based on the time tag difference of the digital weight. Then, combined with the pre-calibrated line scanning cycle and line delay compensation value, motion compensation is applied to the exposure time tag of each row. The corrected line time tag sequence is used as the timestamp of the frame image. The line scanning cycle is obtained by continuously counting and averaging the line synchronization signal. The line delay compensation is calibrated by illuminating with a narrow pulse light source and measuring the time interval from trigger to response in a dark environment, so that the spatial position of each row in the image can accurately correspond to the weighing time.

[0143] After obtaining the weight digital value and its time label, the association module compares it with the corrected time label of each row of the image frame one by one, calculates the spatial deviation distance, marks the row area that falls within the preset tolerance threshold as the valid association row, and selects the row with the smallest deviation first, and binds the image of the row area and the weight digital value as the same vehicle's structured data object. The tolerance threshold combines the length of the weighing sensor along the driving direction and the longitudinal field of view height of the camera component to ensure that even if the vehicle deviates slightly in the lane, the axle and the overall vehicle image can be correctly matched.

[0144] After receiving the structured data object, the storage module first generates a chained digest value in the order of the timestamps. Then, it concatenates the previous digest value, the current timestamp, the weight, and the thumbnail, and performs a hardware-accelerated hash function operation to obtain a new digest, which is then appended to the record. Next, it allocates physical storage block addresses by writing to the sequence number counter, taking the modulo, and looking up the replacement table. The data is then written to the non-volatile memory in sequence. The replacement table is specially designed to ensure that adjacent writes do not fall into adjacent blocks, which helps to balance the erase and write life of each block.

[0145] The communication module reads structured data objects from the storage module in time-stamped order, sends them one by one to the external platform and waits for confirmation. The confirmation management unit maintains the latest confirmed time stamps. Once communication is interrupted and resumed, it starts transmitting from the next record after that stamp, ensuring that the data is reported completely without duplication or omission. The entire process runs in a loop under the unified drive of the reference clock, which not only ensures the precise spatiotemporal synchronization of weighing and images, but also takes into account the integrity and reliability of the data through chained summaries and breakpoint resume mechanisms.

[0146] See Figure 2 As shown in the diagram, the upper part of the figure displays the reference frequency after the phase-locked loop (PLL) frequency multiplication by the clock reference module. The data is synchronously distributed to the sensing module and the acquisition module via equal-length traces. A "co-origin trigger edge" is marked with a dotted line on the same vertical reference, ensuring that the weight analog-to-digital conversion and image line exposure share the same rising edge of the reference clock. This generates co-originating 64-bit time stamps (high 32 bits for seconds count + low 32 bits for clock cycle count). However, frame exposure initiation is not executed cycle-by-cycle. Instead, the acquisition module's internal triggering logic only issues an enable signal if three consecutive weight samples exceed a preset weighing threshold. The first line exposure trigger time is latched only at the next rising edge of the reference clock. It also initiates full-frame exposure, preventing invalid exposure pulses from being generated during periods when there are no vehicles.

[0147] The lower half of the figure refers to line exposure image sensors, with the following labels marked sequentially. Row scan cycle The line delay compensation value δ is calculated based on the effective weighing window of the weighing platform. to Real-time calculated vehicle speed Index each row According to the formula By performing line-by-line displacement compensation, the corrected line time label sequence is finally obtained, thereby eliminating image distortion and weighing position shift caused by the rolling shutter when the vehicle is traveling at high speed.

[0148] See Figure 3 As shown in the diagram, the left side begins with the axle group accumulation and vehicle separation determination: the sensing module temporarily stores the instantaneous weight in the axle group buffer area. When the weight continuously falls below the weighing threshold and the interval exceeds the preset minimum time between axles (e.g., 400 milliseconds), the vehicle is determined to have passed, and the total vehicle weight is accumulated. And take the first timestamp as Submit to the associated module;

[0149] Then it proceeds to the intermediate spatial association matching stage, based on Calculate the spatial deviation distance, in order to To determine the threshold, if there exists that satisfies... If the row with the smallest deviation is selected for binding, and no matching row is found after traversing the entire graph, the process will switch to the abnormal association branch. The row with the smallest absolute deviation will be forcibly bound and marked with "low confidence pending review" before continuing to flow, ensuring that the evidence package is not lost in extreme scenarios.

[0150] The right-side storage stage generates chained digest values ​​in chronological order based on timestamps before writing. Attached to the record, forming a chain of interlocking anti-tampering measures, the written address is moduloed by the write sequence counter and the N-element replacement table is consulted to achieve wear leveling;

[0151] Finally, the communication module sends and records the confirmed timestamps in sequence. Once the interruption is recovered, the transmission resumes from the point of break, ensuring that the data is reported completely without duplication or omission.

[0152] In summary, the system in the above embodiments distributes the reference clock signal uniformly to each functional link, enabling weight acquisition and image exposure to share the same source time tag. Temperature drift compensation and dynamic strain rate correction are introduced at the sensing end, while motion compensation based on vehicle speed is performed on the line exposure time at the image end. Then, a spatial deviation threshold is used to complete the accurate correlation between weight and image area. This system can effectively suppress data misalignment and measurement deviation caused by clock skew, temperature changes, vehicle speed differences, and rolling exposure distortion, thereby improving the reliability of overload control data in terms of temporal consistency and spatial correspondence. On this basis, the wear leveling strategy of permutation table mapping is used during storage to extend the service life of non-volatile media. The sequential appending of chained summary values ​​provides a self-verifiable anti-tampering basis for post-event auditing. The continuation mechanism after communication interruption avoids repeated acquisition or data loss. The above measures jointly ensure the data integrity and transmission continuity of the system during long-term field operation. Moreover, the overall solution is implemented based on the internal resources of the ARM processor without adding additional complex hardware, which is conducive to maintaining the economy and deployment convenience of embedded devices.

[0153] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An embedded traffic control system based on ARM architecture, characterized in that, include: The clock reference module, integrated inside the ARM processor, is used to generate a reference clock signal and distribute the reference clock signal down to various functional modules in the system; The sensing module is used to receive the analog voltage signal output by the road weighing sensor, and uses the rising edge of the reference clock signal as the start trigger for analog-to-digital conversion to convert the analog voltage signal into a digital weight carrying a time tag. The acquisition module is used to connect to the camera component and use the rising edge of the reference clock signal as the start trigger for image frame exposure, so that the image frame after exposure carries a time tag of the same origin as the digital value of weight. The association module is used to obtain the weight digital quantity and its time tag, image frame and its time tag, and bind the weight digital quantity and image frame as the same vehicle structured data object with the time tag as the unique key value; The storage module is used to receive structured data objects and write them to the embedded non-volatile memory according to the time stamp. The communication module outputs structured data objects to external platforms according to the time stamp.

2. The embedded traffic control system based on ARM architecture according to claim 1, characterized in that, The clock reference module includes a phase-locked loop, a clock distribution network, and a timestamp generator integrated into the ARM processor. The phase-locked loop multiplies the external crystal oscillator frequency to the reference frequency. The clock distribution network transmits the generated reference clock signal to the sensing module, acquisition module, association module, storage module and communication module respectively via equal-length traces; The timestamp generator includes a counter that increments on the rising edge of the reference clock signal. The count value of the counter, together with the start-up second count, constitutes the timestamp. The timestamp is a 64-bit unsigned integer, with the high 32 bits representing the number of seconds since system startup and the low 32 bits representing the reference clock cycle count value within the current second.

3. The embedded traffic control system based on ARM architecture according to claim 2, characterized in that, The clock reference module reads the lower 32-bit count values ​​of the time tags latched by the sensing module and the acquisition module on the same reference clock signal edge. If the absolute value of the difference between the two exceeds the preset out-of-synchronization threshold number of times, the clock is determined to be out of synchronization, an alarm signal is generated, and the clock distribution network is triggered to realign and distribute the clock.

4. The embedded traffic control system based on ARM architecture according to claim 1, characterized in that, The sensing module includes an instrumentation amplifier, an anti-aliasing filter, an analog-to-digital converter, a temperature sensor, and a compensation and calculation unit. The instrumentation amplifier receives the analog voltage signal output from the road surface weighing sensor. Its gain is set according to the ratio of the full-scale input range of the analog-to-digital converter to the maximum output voltage amplitude of the road surface weighing sensor under rated load, so that the output signal amplitude matches the input dynamic range of the analog-to-digital converter. The -3dB cutoff frequency of the anti-aliasing filter is set to [value missing]. ,in The reference frequency generated by the clock reference module, where k is a preset multiple greater than 2, is used to suppress frequencies higher than [the specified frequency]. Noise components are superimposed into the baseband; The temperature sensor is thermally coupled to the road surface weighing sensor, acquiring the sensor temperature T in real time. The analog-to-digital converter initiates conversion on the rising edge of the reference clock signal, outputting the raw weight digital value. The compensation calculation unit stores the original weight digital value from the previous sample and assigns a corresponding time tag. and its time label, and based on the current sample The final weight is calculated using the difference Δt between the current time stamp and the previous sampling time stamp, and the temperature T, according to the following formula: ； In the formula: For calibrating the reference temperature; It is a first-order temperature coefficient; It is a second-order temperature coefficient; For dynamic correction of amplitude coefficient; This is the strain rate scaling factor; It is a time interval in seconds, calculated by dividing the difference between the time stamps of two samples by 1 / 2. It can be concluded that; The final The time stamp of the sampling time constitutes the weighted digital quantity carrying the time stamp.

5. The embedded traffic control system based on ARM architecture according to claim 2, characterized in that, The camera component is a line exposure type image sensor; The acquisition module records the time stamp of its first line of exposure trigger time. and the pre-defined row scan cycle And the line delay compensation value δ, where , Both δ and δ are expressed in terms of the number of reference clock cycles; The acquisition module uses the time tag difference between two adjacent weight values ​​provided by the sensing module and the pre-stored length along the driving direction of the road surface weighing sensor. Calculate the vehicle's speed v; The acquisition module performs motion compensation on the exposure time stamp of each row based on the following formula to obtain the corrected row time stamp: ； In the formula: For row index; The preset image sensor center row index; This represents the total number of rows in the image sensor. The reference frequency generated by the clock reference module; The acquisition module uses the corrected row time tag sequence as the time tag carried by the image frame.

6. The embedded traffic control system based on ARM architecture according to claim 5, characterized in that, The associated module obtains the time stamp of the weight digital value. and the row time tag sequence of the image frame And calculate the spatial deviation distance. ; Will satisfy The row range is marked as a valid associated row. If there is more than one valid associated row, select the one that makes the association valid. The smallest row, binds the image of that row region to the weight digital value as a structured data object of the same vehicle; This is the preset spatial tolerance threshold.

7. The embedded traffic control system based on ARM architecture according to claim 1, characterized in that, The embedded non-volatile memory is divided into N physical storage blocks of equal capacity, and the storage module includes a write sequence counter and an address mapping table. The write sequence number counter is set to zero during system initialization, and its value is incremented by one each time a structured data object is written. The address mapping table takes the current write sequence number count as input, takes the modulo of the count value with the total number of physical storage blocks N to obtain the remainder r, and then uses r as the input index to look up the table from the preset N-ary replacement table to output the target physical block address; The preset N-ary permutation table is a set A permutation of the given information, wherein the difference between the output addresses corresponding to any adjacent indices in the permutation is not 1, and the permutation table is generated and fixed in the address mapping table when the system is manufactured. When the value of the write sequence counter reaches its maximum value, the next write operation resets it to zero and increments it again, so that in consecutive write cycles, the number of erases and writes of each physical block tends to be balanced with the increase of the total number of writes. The storage module writes structured data objects into the target physical block output by the address mapping table according to the time stamp.

8. The embedded traffic control system based on ARM architecture according to claim 7, characterized in that, During the operation of the storage module, before writing structured data objects to physical blocks, a chained digest value is generated for each structured data object in time-stamped order: ； In the formula: Hash is a preset cryptographic hash function; The timestamp of the i-th structured data object; Weight (numerical quantity); The image frame is a thumbnail obtained by downsampling. The double vertical line symbol indicates the concatenation of binary data. The storage module stores the chained digest value The data is additionally stored in the corresponding structured data object record.

9. The embedded traffic control system based on ARM architecture according to claim 1, characterized in that, The communication module has a built-in transmission queue and acknowledgment management unit; The communication module sends the structured data objects to the external platform one by one in time tag order, and waits for the external platform to return confirmation information; The confirmation management unit records the latest confirmed timestamp. When communication is interrupted and resumed, it reads the next structured data object with a later confirmation timestamp from the storage module to start the transmission.

10. The embedded traffic control system based on ARM architecture according to claim 1, characterized in that, The clock reference module is connected to the sensing module and the acquisition module via an on-chip bus to establish a clock signal connection. The sensing module, acquisition module, association module, storage module and communication module are connected to each other via an on-chip data bus. The sensing module is connected to the road weighing sensor via an analog-to-digital conversion interface. The acquisition module is connected to the camera component via a serial interface. The storage module establishes a connection with the embedded non-volatile memory through a storage interface, and the communication module establishes a connection with the external platform through a network interface.

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