A coasting time detection method and detection system

Abstract

The present application relates to the technical field of vehicle performance detection, and particularly relates to a coasting time detection system and method. The system comprises: establishing a data link between a main control unit and a speed sampling device, automatically identifying the speed sampling device and completing communication initialization configuration; adjusting the sampling roller to make it abut against the surface of the chassis dynamometer roller and locking the spatial pose through a multi-stage adjusting mechanism; setting a starting speed threshold and an ending speed threshold based on the measured speed interval and configuring a conversion reference; controlling the main control unit to enter a monitoring state, receiving an original pulse signal based on a preset clock frequency and converting it into a real-time linear speed, automatically triggering timing and latching the effective coasting time according to the real-time linear speed; and associating and storing the effective coasting time with test attribute information. The present application realizes self-adaptive and accurate positioning of the sampling roller through the multi-stage adjusting mechanism, and automatically triggers timing based on a one-way continuous downward trend, thereby improving the precision and efficiency of the coasting time detection.

Description

Technical Field

[0001] This invention relates to the field of vehicle performance testing technology, and in particular to a coasting time testing system and method. Background Technology

[0002] Coasting time testing is one of the core components in the calibration of chassis dynamometers used for automotive exhaust pollutant testing. Existing testing instruments mainly consist of a contact-type speed sensor and a data control and processing unit. During use, the sensor is held against the surface of a roller to measure linear velocity. Existing patents disclose related solutions, such as using limiting blocks and locking mechanisms for fixation, or using height adjustment components to adjust the height of the sampling roller and reduce vibration.

[0003] However, the existing technologies mentioned above still have the following shortcomings: First, the installation and fixing methods of the sampling wheel are relatively simple, mostly relying on magnetic adsorption or screw locking, lacking multi-degree-of-freedom fine adjustment capabilities. The contact posture during installation depends on experience judgment, making it difficult to ensure consistency. Vibration during high-speed rotation can easily lead to changes in the contact state, affecting accuracy. Second, non-contact solutions such as optical and laser are easily affected by factors such as light and dust, resulting in unstable signals. Third, timing triggering relies on manual operation, which has reaction delay and human error. Summary of the Invention

[0004] To overcome the above shortcomings, the present invention provides a gliding time detection system and method, which aims to improve the problems of poor installation consistency of sampling wheels, susceptibility to environmental interference and manual timing errors in the prior art.

[0005] In a first aspect, the present invention provides the following technical solution: a method for detecting coasting time, comprising:

[0006] Establish a data link between the main control unit and the speed sampling device, automatically identify the speed sampling device, and perform communication initialization configuration;

[0007] Adjust the sampling roller of the speed sampling device so that the sampling roller abuts against the surface of the chassis dynamometer drum, and lock the spatial position of the sampling roller through a multi-stage adjustment mechanism;

[0008] The starting speed threshold and ending speed threshold are set based on the measured speed range, and the conversion reference of the speed sampling device is configured.

[0009] The main control unit is controlled to enter the monitoring state, receive the original pulse signal in real time based on the preset clock frequency and convert it into real-time linear velocity, and automatically trigger timing and lock the effective coasting time according to the real-time linear velocity.

[0010] The effective gliding time is associated with and stored with the test attribute information.

[0011] Furthermore, the step of automatically identifying the velocity sampling device includes:

[0012] The main control unit monitors the access status of external devices in real time and automatically identifies the device type when the speed sampling device is detected to be connected.

[0013] Based on the recognition results, the corresponding communication protocol is loaded, and the communication parameters are configured and the registers are initialized.

[0014] Furthermore, the step of locking the spatial pose of the sampling roller through a multi-level adjustment mechanism specifically includes the step of spatial pose initialization:

[0015] The sampling roller is positioned and coupled to the chassis dynamometer frame by magnetic adsorption fixation.

[0016] By adjusting the multi-stage adjustment mechanism, the spatial attitude parameters of the sampling roller are determined, so that the sampling roller abuts against the surface of the drum.

[0017] By adjusting the feed amount of the multi-stage adjustment mechanism, the sampling roller is driven to move radially along the drum until it makes initial contact with the drum surface and the multi-stage adjustment mechanism is locked.

[0018] Furthermore, the spatial pose initialization also includes an adaptive optimization step:

[0019] Rotate the chassis dynamometer roller, and use the friction between the sampling roller and the roller surface to drive the sampling roller to generate a follow-up displacement, so that it deflects to the target position that is stably in contact with the roller surface;

[0020] After reaching a stable engagement state, the multi-stage adjustment mechanism is locked again to fix the sampling roller at the target pose.

[0021] Furthermore, the conversion benchmark includes at least the diameter parameter of the sampling roller and the number of encoder pulses per revolution.

[0022] Furthermore, before converting to real-time linear velocity, the original pulse signal is digitally filtered and de-jittered to eliminate measurement noise introduced by mechanical vibration.

[0023] Furthermore, the step of automatically triggering timing and locking the valid coasting time based on the real-time linear velocity includes:

[0024] When the real-time linear velocity is detected to be continuously decreasing in a unidirectional direction from the initial velocity threshold, timing is automatically started.

[0025] When the real-time linear velocity is detected to continuously decrease to the end speed threshold, the timing is automatically stopped and the current time period is locked as the valid coasting time.

[0026] Furthermore, the test attribute information includes at least one of the following: test timestamp, unique device serial number, operator identifier, and ambient temperature parameter.

[0027] Furthermore, it also includes a calibration step:

[0028] A standard square wave signal is connected to the main control unit, and the theoretical speed value is calculated based on the frequency of the standard square wave signal and the conversion reference.

[0029] The theoretical speed value is compared with the measured speed value, and the conversion benchmark is corrected based on the comparison results.

[0030] Secondly, the present invention provides the following technical solution: a coasting time detection system for implementing the above-mentioned coasting time detection method, the system comprising:

[0031] The link initialization module is used to establish a data link between the main control unit and the speed sampling device, automatically identify the speed sampling device, and perform communication initialization configuration.

[0032] The position and pose adjustment and locking module is used to adjust the sampling roller of the speed sampling device so that the sampling roller abuts against the surface of the chassis dynamometer drum, and locks the spatial position and pose of the sampling roller through a multi-stage adjustment mechanism.

[0033] The parameter configuration setting module is used to set the starting speed threshold and the ending speed threshold based on the measured speed range, and to configure the conversion reference of the speed sampling device;

[0034] The coasting monitoring and processing module is used to control the main control unit to enter the monitoring state, receive the original pulse signal in real time based on the preset clock frequency and convert it into real-time linear speed, and automatically trigger timing and lock the effective coasting time according to the real-time linear speed.

[0035] The data association and storage module is used to associate and store the effective gliding time with the test attribute information.

[0036] The present invention has the following beneficial effects:

[0037] 1. In this invention, the spatial pose of the sampling roller is coarsely and finely adjusted through a multi-stage adjustment mechanism, and the sampling roller is driven by the friction force of the roller to adaptively deflect to a stable and matching target pose, thereby achieving automatic parallelism between the axis of the sampling roller and the axis of the roller, eliminating spatial pose deviation and lateral friction resistance caused by manual installation, and ensuring the consistency of the contact posture.

[0038] 2. In this invention, by continuously comparing adjacent sampling points to determine whether the speed shows a unidirectional continuous downward trend from the initial speed threshold, the timing is automatically started when the condition is met, and the timing is automatically stopped and the effective gliding time is locked when the speed drops to the end threshold. This realizes the fully automatic triggering of the timer and eliminates the reaction delay and human error of manual operation.

[0039] 3. In this invention, the speed sampling device is connected and used immediately by the main control unit through real-time monitoring of the connection status of the speed sampling device and automatic identification of the device type. No manual configuration of communication parameters is required, which simplifies the detection process. Attached Figure Description

[0040] Figure 1 This is a flowchart of a coasting time detection method proposed in this invention;

[0041] Figure 2 This is a flowchart of the spatial pose calibration process proposed in this invention;

[0042] Figure 3 This is the core detection and automatic judgment flowchart proposed in this invention;

[0043] Figure 4 This is a flowchart of the system self-calibration process proposed in this invention;

[0044] Figure 5 This is a diagram of a vehicle performance testing system architecture proposed in this invention. Detailed Implementation

[0045] The technical solutions in 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, and 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.

[0046] Example 1

[0047] In a first embodiment of the present invention, the present invention provides a method for detecting coasting time, such as... Figure 1 As shown, it includes the following steps:

[0048] S100: Establish a data link between the main control unit and the speed sampling device, automatically identify the speed sampling device, and perform communication initialization configuration;

[0049] Furthermore, the step of automatically identifying the velocity sampling device includes:

[0050] The main control unit monitors the access status of external devices in real time and automatically identifies the device type when the speed sampling device is detected to be connected.

[0051] Based on the recognition results, the corresponding communication protocol is loaded, and the communication parameters are configured and the registers are initialized.

[0052] Specifically, the signal output terminal of the speed sampling device is connected to the speed encoder interface on the back of the main control unit via a signal transmission line. The controller inside the main control unit monitors the connection status of this interface in real time through a preset monitoring program, and automatically identifies the type of connected device when a speed sampling device is detected.

[0053] Based on the identified device type, the main control unit retrieves and loads the matching communication protocol from the storage module, and completes the communication parameter configuration and register initialization to ensure accurate capture of the pulse signals generated by the speed sampling device. During this process, the main control unit confirms the integrity of the signal transmission channel, ensuring the data link between the main control unit and the speed sampling device is ready.

[0054] After completing the communication initialization configuration, the main control unit uses the given roller diameter... and encoder pulse count per revolution In this embodiment, it is given , A conversion benchmark from pulse frequency to linear velocity is established. The main control unit calculates the pulse frequency based on the real-time received pulse frequency. Calculate the real-time linear velocity using the following formula. :

[0055] ;

[0056] in, Real-time linear velocity, unit: It is used to reflect the instantaneous motion state of the chassis dynamometer roller; The diameter of the sampling roller, in units of ; The original pulse frequency received by the main control unit, in units of This is generated by the encoder rotating with the roller; The number of pulses generated by the encoder in one revolution, in units of 3.6 is a unit conversion factor used to convert... Convert to .

[0057] By real-time monitoring of the access status of the speed sampling device and automatic identification of the device type by the main control unit, and by automatically loading the matching communication protocol and completing the parameter configuration based on the identification results, the speed sampling device can be used immediately after connection, avoiding the tedious operation of manually configuring communication parameters in traditional solutions. At the same time, by establishing a conversion benchmark from pulse frequency to linear velocity based on roller diameter and encoder pulse number, physical parameters and mathematical formulas are integrated into a unified linear velocity calculation model, so that subsequent coasting time acquisition has a clear physical quantity traceability basis, providing measurement assurance for the accuracy and consistency of coasting time detection.

[0058] S200: Adjust the sampling roller of the speed sampling device so that the sampling roller abuts against the surface of the chassis dynamometer drum, and lock the spatial position of the sampling roller through a multi-stage adjustment mechanism;

[0059] Furthermore, such as Figure 2 As shown, locking the spatial pose of the sampling roller through a multi-level adjustment mechanism specifically includes the step of spatial pose initialization:

[0060] The sampling roller is positioned and coupled to the chassis dynamometer frame by magnetic adsorption fixation.

[0061] By adjusting the multi-stage adjustment mechanism, the spatial attitude parameters of the sampling roller are determined, so that the sampling roller abuts against the surface of the drum.

[0062] By adjusting the feed amount of the multi-stage adjustment mechanism, the sampling roller is driven to move radially along the drum until it makes initial contact with the drum surface and the multi-stage adjustment mechanism is locked.

[0063] Specifically, the entire sampling mechanism is placed on the iron plate surface of the chassis dynamometer stand by utilizing a strong magnetic force manually switched magnet mounting base at the bottom of the speed sampling device. The magnetic switch is then operated to activate the magnetic force, using magnetic attraction to securely couple the mounting base to the stand surface. In this embodiment, the magnetic base's attraction force is configured to resist mechanical vibrations generated during the test, ensuring that the sampling mechanism does not shift or loosen under high-speed rotation conditions.

[0064] Subsequently, the operator performs initial spatial orientation positioning using a multi-stage adjustment mechanism. This mechanism includes a multi-directionally rotatable support rod, an external threaded handle, and an internal threaded handle. The operator releases the locking handle and adjusts the height of the support rod and the angle of the swing arm, bringing the sampling roller initially close to the surface of the chassis dynamometer's drum. At this point, the height and swing angle of the rod are initially fixed using the external threaded handle.

[0065] Next, the operator drives the sampling roller to move radially along the drum by adjusting the feed compensation component of the multi-stage adjustment mechanism. During this process, the operator continuously observes the contact between the sampling roller and the drum surface until initial contact is achieved. At this point, the radial feed position of the sampling roller is pre-locked using the internal thread handle to maintain the sampling roller in the initial contact state.

[0066] In this embodiment, after completing the radial feed fine-tuning, the external threaded handle is in a slightly locked state, i.e., not completely locked, which allows the multi-stage adjustment mechanism to retain a certain degree of freedom of movement in this state. This semi-locked state allows the sampling roller to adaptively deflect with friction during the subsequent drum rotation step, thereby automatically adjusting to the target pose that stably engages with the drum surface; on the other hand, since each adjustment component is constrained to the initial contact position, uncontrolled shaking caused by complete loosening can be avoided, ensuring the safety and controllability of the adjustment process. This state is defined as a semi-locked state in this embodiment, that is, the spatial pose of the sampling roller is constrained to the initial contact position, but each adjustment component still retains a limited degree of freedom of movement.

[0067] Furthermore, the spatial pose initialization also includes an adaptive optimization step:

[0068] Rotate the chassis dynamometer roller, and use the friction between the sampling roller and the roller surface to drive the sampling roller to generate a follow-up displacement, so that it deflects to the target position that is stably in contact with the roller surface;

[0069] After reaching a stable engagement state, the multi-stage adjustment mechanism is locked again to fix the sampling roller at the target pose.

[0070] Specifically, to eliminate spatial orientation deviations during installation and achieve an ideal measurement state, the system executes an adaptive optimization step. The operator drives the chassis dynamometer roller to rotate at a low speed. At this time, the sampling roller begins to rotate under the frictional force on the roller surface, producing a small follow-up displacement.

[0071] Since the multi-stage adjustment mechanism is in a semi-locked state at this time, that is, each adjustment component is constrained but retains a limited margin of movement. Preferably, the support of the sampling roller is mounted via a pivot structure, possessing rotational freedom about a direction perpendicular to the roller axis, to ensure that it can freely deflect to the target pose of stable engagement with the roller surface under the action of friction. The sampling roller will automatically deflect according to the principle of force balance until its rotation axis is parallel to the rotation axis of the chassis dynamometer roller, that is, to achieve the target pose of perpendicular tangency. When the sampling roller achieves stable rotation without abnormal jumping during the follow-up process, it indicates that the sampling roller has formed a stable engagement with the roller surface.

[0072] After the sampling roller and the roller surface reach a stable engagement state, the operator locks the external thread handle to completely lock the multi-stage adjustment mechanism, so that the spatial pose of the sampling roller is fixed at the target pose, thus completing the rigid solidification of the final spatial pose of the sampling roller.

[0073] Under stable engagement conditions, there is no relative sliding between the sampling roller and the drum surface, and the linear velocity of the sampling roller is consistent with the linear velocity of the drum surface, thus ensuring the measurement accuracy of the sliding time detection. Through the above-mentioned multi-stage adjustment and adaptive optimization process, the lateral frictional resistance caused by the installation tilt of the sampling roller can be effectively avoided, ensuring the accuracy and consistency of speed acquisition.

[0074] The sampling mechanism is quickly and reliably installed on the chassis dynamometer frame by magnetic adsorption. The two-stage adjustment of the linkage and feed compensation component of the multi-stage adjustment mechanism enables the initial positioning of the sampling roller's spatial attitude and independent control of the contact feed amount. At the same time, rotating the drum with the external thread handle in a semi-locked state uses friction to drive the sampling roller to adaptively deflect to the target position that stably matches the drum surface, so that the axis of the sampling roller and the axis of the drum automatically tend to be parallel. This eliminates spatial attitude deviation and lateral frictional resistance caused by manual installation, and provides physical contact guarantee for the accuracy and consistency of coasting time detection.

[0075] S300: Set the starting speed threshold and ending speed threshold based on the measured speed range, and configure the conversion reference of the speed sampling device;

[0076] Furthermore, the conversion benchmark includes at least the diameter parameter of the sampling roller and the number of encoder pulses per revolution.

[0077] Specifically, after completing the hardware connection and physical installation, the main control unit receives parameter configuration commands via an integrated touchscreen and enters the parameter setting interface. The system first configures the conversion reference for the speed sampling device, which serves as the mathematical basis for subsequently converting electrical pulse signals into physical motion parameters. In this embodiment, the system receives the actual diameter of the input sampling roller. for and the number of pulses per revolution of the encoder. for These data are stored in the non-volatile memory of the main control unit as fixed coefficients in the linear velocity conversion formula, used to calculate the edge linear velocity of the sampling roller in real time.

[0078] Based on specific testing standards or calibration specifications, trigger boundary conditions for coasting time testing are set, namely, the starting speed threshold and the ending speed threshold. In this embodiment, for the performance calibration task of the chassis dynamometer, the starting speed threshold is set... Set as (The specific value is only an exemplary implementation method; in actual applications, it can be set to other values ​​according to the requirements of different testing standards or calibration specifications.) End speed threshold. Set as These two thresholds constitute the speed monitoring range for automatic timing.

[0079] By configuring the conversion benchmark, the main control unit establishes a linear mapping relationship between the pulse frequency signal and the real-time linear velocity, ensuring high accuracy in speed measurement. By setting the start and end speed thresholds, the logical boundary of the system's automatic trigger timer is determined, ensuring that the recording of coasting time is strictly locked within the preset speed range. This eliminates timing lag or lead errors caused by manual operation of the timer, thus providing a standardized data basis for evaluating chassis transmission system resistance and calculating fuel-saving and emission-reduction indicators.

[0080] S400: Control the main control unit to enter the monitoring state, receive the original pulse signal in real time based on the preset clock frequency and convert it into real-time linear speed, and automatically trigger timing and lock the effective coasting time according to the real-time linear speed.

[0081] Furthermore, before converting to real-time linear velocity, the original pulse signal is digitally filtered and de-jittered to eliminate measurement noise introduced by mechanical vibration.

[0082] Specifically, the main control unit enters high-speed monitoring mode in response to the start test command. The high-speed counter inside the main control unit operates according to a preset clock frequency (in this embodiment, ). The sampling frequency is used to capture the original pulse signal transmitted by the speed sampling device. Since the chassis dynamometer generates mechanical vibrations during high-speed rotation, which may cause pulse waveform distortion or generate spurious pulses, the main control unit uses a built-in digital filter to de-jitter the signal. In this embodiment, the digital filter uses a moving average filtering algorithm to de-jitter the signal, i.e., at a continuous sampling frequency. The average value of each sampling point is used as the current effective pulse frequency, where This is the depth of the sliding window. Those skilled in the art can determine this based on the actual signal characteristics and noise level. The specific value of . In one specific implementation of this embodiment, The value is set to 10 to balance signal response speed and noise suppression effect.

[0083] Furthermore, such as Figure 3 As shown, the steps of automatically triggering timing and locking the valid coasting time based on the real-time linear velocity include:

[0084] When the real-time linear velocity is detected to be continuously decreasing in a unidirectional direction from the initial velocity threshold, timing is automatically started.

[0085] When the real-time linear velocity is detected to continuously decrease to the end speed threshold, the timing is automatically stopped and the current time period is locked as the valid coasting time.

[0086] Specifically, the main control unit calculates the linear velocity in real time using the filtered frequency described above. When the drive power of the chassis dynamometer is disconnected, the roller begins to slide under the action of inertia, with a linear velocity... The speed shows a downward trend. The main control unit determines whether the speed has exceeded the initial speed threshold by continuously comparing the speed values ​​of adjacent sampling periods. It began a one-way, continuous decline.

[0087] The unidirectional continuous downward trend described in this article refers to the overall direction of change of real-time linear velocity in a macroscopic manner being a unidirectional decrease. It allows for minor local fluctuations caused by mechanical vibration, quantization error, or signal noise, but the amplitude of the local fluctuations does not exceed a preset fluctuation threshold and does not change the overall downward direction of the velocity.

[0088] In this embodiment, when Furthermore, when multiple consecutive sampling points (such as more than 3) show a downward trend, the timer inside the main control unit will automatically start timing.

[0089] During the timing process, the controller continuously monitors the linear velocity. When linear velocity is detected Further decrease to the end speed threshold (Right now When the clock difference for that period of time is reached, the timer immediately stops running and locks the clock difference as the valid coasting time. At this time, the main control unit locks the clock difference for that period of time as the valid coasting time. In this embodiment, the system timing error is better than... It meets the calibration specifications of the coasting time meter.

[0090] By performing a moving average filter on the original pulse signal after the main control unit enters the monitoring state, the interference of mechanical vibration on the pulse signal during the high-speed rotation of the chassis dynamometer is eliminated, improving the stability and smoothness of speed calculation. At the same time, by continuously comparing adjacent sampling points, it is determined whether the speed shows a unidirectional continuous downward trend from the initial speed threshold and the timing is automatically started when the condition is met, and the timing is automatically stopped when the speed drops to the end threshold, realizing the fully automatic triggering of the timer without manual intervention. Based on the combination of filtering and automatic triggering timing logic, closed-loop control of the coasting time measurement process is realized, ensuring the high repeatability of coasting time acquisition and the reliability of measurement results within the same speed range.

[0091] S500: The effective gliding time is associated with and stored with the test attribute information.

[0092] Furthermore, the test attribute information includes at least one of the following: test timestamp, unique device serial number, operator identifier, and ambient temperature parameter.

[0093] Specifically, the main control unit locks the effective coasting time. Subsequently, internal system resources and sensor data are synchronously accessed. The system clock chip generates the current test timestamp to record the precise time the test occurred. In this embodiment, the test timestamp is accurate to the second, such as 2026-06-18 08:49:33. The device's unique serial number serves as a unique identifier for the hardware and is read from the read-only memory by the main control unit to ensure that the test data is bound to the specific coasting time detector hardware. The operator's identifier is obtained through the login interface of the integrated touchscreen and is used to record the identity information of the operator performing the current test task. The main control unit collects the temperature parameters of the test environment through the built-in ambient temperature sensor or an externally connected temperature and humidity sensor. The real-time temperature data is used to assess the potential impact of environmental factors on the viscosity of the chassis lubricating oil and the roller resistance.

[0094] In the data storage stage, the main control unit associates the aforementioned discrete attribute information with the effective coasting time according to a preset structured format to form a complete detection record. To meet the requirement of detection repeatability, the system automatically records at least three sets of coasting time data and generates a data table during a complete test process.

[0095] The resulting associated dataset is stored in the storage module inside the main control unit. When an external USB storage device is connected, the main control unit responds to the export command on the touchscreen and exports the historical gliding time data and associated attribute information via the USB interface for external devices to perform data analysis.

[0096] By associating and storing the effective coasting time with the test timestamp, the equipment's unique serial number, the operator's identification, and the ambient temperature parameters, each set of coasting time data has complete traceability information. By automatically recording at least three sets of coasting time data and generating a data table in a single test process, the recording requirements for repeatability of the test are met. At the same time, a data export function is provided through a USB interface, allowing the stored associated data to be accessed and analyzed by external devices. This achieves the traceability and analyzability of the test data, providing a data foundation for the compliance review of the chassis dynamometer coasting test and subsequent fault diagnosis.

[0097] Furthermore, such as Figure 4 As shown, it also includes a calibration step:

[0098] A standard square wave signal is connected to the main control unit, and the theoretical speed value is calculated based on the frequency of the standard square wave signal and the conversion reference.

[0099] The theoretical speed value is compared with the measured speed value, and the conversion benchmark is corrected based on the comparison results.

[0100] Specifically, the calibration steps are performed before the device is used for the first time, automatically during device use at a preset cycle, or in response to a user's manual calibration command. The calibration process begins with a hardware link switch. The operator connects the calibration signal input line to the speed encoder interface on the back of the main control unit. The signal input terminal of the calibration signal input line is connected to an external standard signal generator, such as a sweep frequency signal generator. The standard signal generator inputs a standard square wave signal with a stable frequency to the main control unit.

[0101] After receiving the standard square wave signal, the main control unit calculates the theoretical speed value based on a preset conversion benchmark. The physical calculation model for the theoretical speed value is as follows:

[0102] ;

[0103] in, This is the theoretical speed value, in units of... , as a reference for calibration; In this embodiment, the diameter parameter of the sampling roller is set. ; The known frequency output by a standard signal generator, in units of... ; The number of pulses per revolution of the encoder is set to [value] in this embodiment. ; and These are the unit conversion factor and the constant for pi, respectively. In this embodiment, when , , At that time, the theoretical speed value is approximately .

[0104] The main control unit enters the coasting time test interface, receiving a standard square wave signal while simultaneously calculating and displaying the measured speed value in real time. The operator compares the measured speed value with the theoretical speed value. If the deviation exceeds a preset accuracy threshold, the conversion benchmark needs to be corrected. The formulas for deviation evaluation and correction coefficients are as follows:

[0105] ;

[0106] in, This is the vehicle speed correction factor, used to proportionally compensate the original conversion benchmark; This is the theoretical velocity value calculated using a standard signal; This is the actual speed value currently collected and displayed by the device.

[0107] In this embodiment, according to the technical specifications, the speed measurement accuracy is within... to The interval should reach If the deviation between the measured speed value and the theoretical value exceeds the error range, the operator can access the parameter setting page via the integrated touchscreen, input and save the calculated vehicle speed correction coefficient. In subsequent measurement logic, the main control unit will multiply the real-time calculated linear velocity by this correction coefficient to complete the dynamic correction of the conversion benchmark.

[0108] In addition, for time accuracy calibration, operators use the linear sweep function of a standard signal generator to set specific start and end frequencies and sweep times. The main control unit calculates the theoretical time required for the corresponding speed range based on these parameters and compares it with the measured coasting time. If there is a deviation, it is corrected by adding a time coefficient.

[0109] By inputting a standard square wave signal to the main control unit and calculating the theoretical speed value based on the conversion reference, independent verification of speed measurement accuracy is achieved. The system can complete self-calibration without relying on an external speed reference source. The vehicle speed correction coefficient is calculated by comparing the theoretical speed value with the measured speed value. The correction coefficient is applied to the real-time linear velocity to achieve dynamic correction of the conversion reference. This eliminates measurement errors caused by long-term wear of the sampling roller or drift of electronic component characteristics. The time accuracy is calibrated according to the linear frequency sweep function, achieving system-level accuracy assurance for both speed and time parameters, ensuring that the coasting time detector maintains a high-precision measurement state for a long time.

[0110] Example 2

[0111] In actual vehicle inspection stations, the coasting time test of the chassis dynamometer is one of the core items of vehicle annual inspection and comprehensive performance testing. Inspectors need to install the speed sampling device of the coasting time meter in conjunction with the rollers of the chassis dynamometer. By measuring the coasting time of the rollers after power is disconnected, they can assess whether parameters such as the basic inertia and coasting time under load of the dynamometer meet the requirements of the metrological calibration standard (JJF 1221-2009).

[0112] Currently, the installation and operation of coasting time detectors have the following shortcomings: Existing speed sampling devices mostly use non-contact photoelectric sensors, which are easily affected by stray light interference; contact-type solutions have fixed sampling roller installation positions, lacking multi-degree-of-freedom fine adjustment and reliable locking mechanisms, and vibration during high-speed rotation can easily cause changes in the contact state, affecting the accuracy and stability of speed acquisition. The timing of coasting time start and stop largely relies on manual operation, resulting in reaction delays and subjective errors; detection data is recorded only in temporary numerical form, lacking a mechanism for associating and storing information with attributes such as time, equipment, personnel, and environment, making it difficult to achieve objective traceability of the detection data. To solve the above problems, this invention provides a vehicle performance testing system, the structure of which is as follows: Figure 5 As shown. The system includes a link initialization module, a pose adjustment and locking module, a parameter configuration setting module, a gliding monitoring and processing module, and a data association and storage module. Its specific implementation process is as follows:

[0113] Link initialization module

[0114] This module connects the speed sampling device to the main control unit. The main control unit monitors the interface access status in real time, automatically identifies the device type when a device is detected, loads the corresponding communication protocol, and completes parameter configuration, putting the data link in a ready state. A conversion benchmark from pulse frequency to linear speed is established based on the roller diameter and encoder pulse count.

[0115] Position adjustment and locking module

[0116] The module uses a magnetic mounting base to attach the sampling mechanism to the platform surface. The height of the connecting rod and the angle of the swing arm are adjusted using the external threaded handle to bring the sampling roller close to the drum surface. The sampling roller is then driven radially by the internal threaded handle until initial contact is made. With the external threaded handle in a semi-locked state, rotating the drum causes the sampling roller to deflect to a stable engagement position. Locking the external threaded handle completes the fixation.

[0117] Parameter configuration setting module

[0118] This module accesses the parameter setting interface via a touchscreen, receives the input roller diameter and encoder pulse count, and saves them in memory as conversion coefficients. It sets start and end speed thresholds based on detection standards, which serve as the speed monitoring range for the timer.

[0119] Taxiing monitoring and processing module

[0120] This module enters high-speed monitoring mode, capturing pulse signals at a preset clock frequency. After being processed by a digital filter to remove jitter, the signals are converted into real-time linear speed. After power is disconnected, the module checks whether the linear speed is continuously decreasing in one direction from the initial threshold. If the condition is met, timing starts; when the linear speed decreases to the end threshold, timing stops, and the current time period is locked as the valid coasting time.

[0121] Data association storage module

[0122] After locking in the valid coasting time, this module acquires the test timestamp, device serial number, operator identification, and ambient temperature parameters, and stores this information in association with the coasting time to form a test record. The system automatically records at least three sets of coasting time data and generates a data table, which can be exported via USB interface for analysis by external devices.

[0123] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting coasting time, characterized in that, include: Establish a data link between the main control unit and the speed sampling device, automatically identify the speed sampling device, and perform communication initialization configuration; Adjust the sampling roller of the speed sampling device so that the sampling roller abuts against the surface of the chassis dynamometer drum, and lock the spatial position of the sampling roller through a multi-stage adjustment mechanism; The starting speed threshold and ending speed threshold are set based on the measured speed range, and the conversion reference of the speed sampling device is configured. The main control unit is controlled to enter the monitoring state, receive the original pulse signal in real time based on the preset clock frequency and convert it into real-time linear velocity, and automatically trigger timing and lock the effective coasting time according to the real-time linear velocity. The effective gliding time is associated with and stored with the test attribute information; The step of locking the spatial pose of the sampling roller through a multi-level adjustment mechanism specifically includes the step of spatial pose initialization: The sampling roller is positioned and coupled to the chassis dynamometer frame by magnetic adsorption fixation. By adjusting the multi-stage adjustment mechanism, the spatial attitude parameters of the sampling roller are determined, so that the sampling roller abuts against the surface of the drum. By adjusting the feed rate of the multi-stage adjustment mechanism, the sampling roller is driven to move radially along the drum until it makes initial contact with the drum surface, and then the multi-stage adjustment mechanism is locked. The spatial pose initialization also includes an adaptive optimization step: Rotate the chassis dynamometer roller, and use the friction between the sampling roller and the roller surface to drive the sampling roller to generate a follow-up displacement, so that it deflects to the target position that is stably in contact with the roller surface; After reaching a stable engagement state, the multi-stage adjustment mechanism is locked again to fix the sampling roller at the target pose.

2. The coasting time detection method according to claim 1, characterized in that, The step of automatically identifying the velocity sampling device includes: The main control unit monitors the access status of external devices in real time and automatically identifies the device type when the speed sampling device is detected to be connected. Based on the recognition results, the corresponding communication protocol is loaded, and the communication parameters are configured and the registers are initialized.

3. The coasting time detection method according to claim 1, characterized in that, The conversion reference includes at least the diameter parameter of the sampling roller and the number of encoder pulses per revolution.

4. The coasting time detection method according to claim 1, characterized in that, Before converting to real-time linear velocity, the original pulse signal is digitally filtered and de-jittered to eliminate measurement noise introduced by mechanical vibration.

5. The coasting time detection method according to claim 1, characterized in that, The steps of automatically triggering timing and locking the valid coasting time based on the real-time linear velocity include: When the real-time linear velocity is detected to be continuously decreasing in a unidirectional direction from the initial velocity threshold, timing is automatically started. When the real-time linear velocity is detected to continuously decrease to the end speed threshold, the timing is automatically stopped and the current time period is locked as the valid coasting time.

6. The coasting time detection method according to claim 1, characterized in that, The test attribute information includes at least one of the following: test timestamp, unique device serial number, operator identifier, and ambient temperature parameter.

7. The coasting time detection method according to claim 1, characterized in that, It also includes a calibration step: A standard square wave signal is connected to the main control unit, and the theoretical speed value is calculated based on the frequency of the standard square wave signal and the conversion reference. The theoretical speed value is compared with the measured speed value, and the conversion benchmark is corrected based on the comparison results.

8. A coasting time detection system, characterized in that, The system for the coasting time detection method according to any one of claims 1-7 comprises: The link initialization module is used to establish a data link between the main control unit and the speed sampling device, automatically identify the speed sampling device, and perform communication initialization configuration. The position and pose adjustment and locking module is used to adjust the sampling roller of the speed sampling device so that the sampling roller abuts against the surface of the chassis dynamometer drum, and locks the spatial position and pose of the sampling roller through a multi-stage adjustment mechanism. The parameter configuration setting module is used to set the starting speed threshold and the ending speed threshold based on the measured speed range, and to configure the conversion reference of the speed sampling device; The coasting monitoring and processing module is used to control the main control unit to enter the monitoring state, receive the original pulse signal in real time based on the preset clock frequency and convert it into real-time linear velocity, and automatically trigger timing and lock the effective coasting time according to the real-time linear velocity. The data association and storage module is used to associate and store the effective gliding time with the test attribute information.

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