Brake performance detection device and detection method based on vehicle integrated inertial navigation technology, and computer system

Abstract

The invention discloses a brake performance detection device based on a vehicular integrated inertial navigation technology, which comprises a brake sensor for monitoring the state change of a brake pedal in the movement of a vehicle in real time, capturing the starting time and the ending time of a brake process, and outputting the starting time and the ending time to a brake performance resolving module; the vehicle combined inertial navigation module is used for detecting the kinematics state of the vehicle in real time and outputting the kinematics state to the braking performance resolving module; the braking performance resolving module is used for acquiring state data of a braking pedal and state data of vehicle kinematics and calculating braking performance parameters according to the starting time and the ending time of braking; and the error compensation module is used for compensating the brake performance parameter error caused by the delay of brake triggering and the inconsistency of the actual triggering speed and the target speed of the vehicle. The method has the advantages that data of multiple sensors are fused, and the precision and reliability of vehicle braking performance detection are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive braking performance detection, and particularly relates to a braking performance detection device, a detection method, and a computer system based on vehicle-mounted integrated inertial navigation technology. Background Art

[0002] With the rapid development of autonomous driving technology, the automotive industry has put forward higher requirements for intelligent, safe, and efficient driving experiences. In this context, active safety systems and Automatic Emergency Braking (AEB) systems have become particularly important in autonomous driving. In particular, the detection of braking performance directly affects the overall safety of the vehicle. To ensure that autonomous vehicles can accurately perceive the braking process, including braking time, braking deceleration, and other vehicle kinematic states, the accuracy and real-time performance of the detection system are crucial. However, most existing braking test systems rely on a single sensor to detect the kinematic state of the vehicle. Several technical solutions for existing brake test systems are as follows: Millimeter-wave radar, millimeter-wave radar uses millimeter-band electromagnetic waves (usually 30 GHz to 300 GHz) for detection, and is commonly used to measure the distance, speed, and angle of an object. It has the advantages of all-weather operation, strong penetration, and a relatively long detection distance. However, it also has the disadvantages of relatively low resolution, relatively poor angle and distance resolution, and inability to accurately draw the shape and contour of an object. The target recognition ability is limited. Due to the relatively low resolution, millimeter-wave radar has deficiencies in accurate target recognition and classification.

[0003] LiDAR, LiDAR measures the distance of an object by emitting laser beams and receiving reflected signals, generating high-resolution three-dimensional point cloud data. It has the advantages of high precision, a large detection range, and strong target recognition ability. However, it has the disadvantages of high cost: the hardware cost of LiDAR is relatively high, especially for high-precision mechanical LiDAR. Poor environmental adaptability, the performance will decline under harsh weather conditions such as rain and fog, and the laser may be absorbed or scattered. High power consumption, compared with other sensors, LiDAR has a relatively high power consumption.

[0004] A camera uses optical imaging technology to obtain a two-dimensional image or video of a scene. Combining computer vision algorithms, functions such as target detection, recognition, and tracking can be achieved. It has the advantages of low cost, rich information, and being friendly to human understanding. However, it also has the disadvantages of relying on lighting conditions, and its performance will significantly decline in cases of insufficient light (at night, in shadows) or excessive light (direct sunlight). Weak three-dimensional perception ability: The camera obtains two-dimensional information, and usually three-dimensional spatial information needs to be obtained through stereo vision or multi-sensor fusion. Poor anti-interference ability, strong light, shadows, dynamic changes, etc. in the environment are likely to interfere with the perception ability of the camera, etc.

[0005] Using a single sensor such as millimeter-wave radar, lidar, or camera to detect the kinematic state of a vehicle has the disadvantages of low resolution, weak target recognition ability; high hardware cost, poor environmental adaptability, and high power consumption; relying on lighting conditions, weak three-dimensional perception ability, and poor anti-interference ability, etc., and it is impossible to accurately evaluate and test the braking performance of the vehicle, which is the place that this application needs to focus on improving. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a braking performance detection device, detection method, and computer system based on vehicle-mounted integrated inertial navigation technology, which fuse the data of multiple sensors and significantly improve the accuracy and reliability of vehicle braking performance detection.

[0007] To solve the above technical problems, the present invention provides a braking performance detection device based on vehicle-mounted integrated inertial navigation technology, including: A brake pedal state detection module, including a brake sensor, which continuously monitors the state change of the brake pedal during vehicle movement, captures the start time and end time of the braking process, and outputs them to the braking performance calculation module; A vehicle-mounted integrated inertial navigation module, which integrates an inertial sensor, a satellite receiver (GNSS), and a wheel speed sensor. The inertial sensor continuously detects the attitude, angular velocity, and acceleration of the vehicle. The satellite receiver provides the global positioning data of the vehicle. The wheel speed sensor monitors the wheel speeds of each wheel of the vehicle. By fusing the data of these three sensors, it continuously provides high-precision vehicle kinematic state data, including position, speed, acceleration, angular velocity, and attitude angle, and outputs them to the braking performance calculation module; A braking performance calculation module, which obtains the state data of the brake pedal and the state data of the vehicle kinematics, and calculates braking performance parameters, including braking distance, braking time, and braking deceleration, according to the start and end times of braking; An error compensation module, which obtains the braking performance parameters and compensates for the errors of the braking performance parameters caused by the delay of braking triggering and the inconsistency between the actual triggering speed and the target speed of the vehicle; A storage module, which stores log data, The communication peripheral module provides an interface for external interaction.

[0008] The present invention also provides a vehicle equipped with the braking performance detection device based on the vehicle integrated inertial navigation technology.

[0009] The present invention also provides a braking performance detection method based on the vehicle integrated inertial navigation technology, including the following steps: Step S1: The vehicle integrated inertial navigation module real-time detects the kinematic state of the vehicle and outputs it to the braking performance calculation module; The inertial sensor real-time detects the attitude, acceleration, and angular velocity of the vehicle, providing high-frequency short-term accurate motion information; The satellite receiver provides the original satellite data of the vehicle, providing the absolute position and velocity information in the stable global coordinate system for a long time; The wheel speed sensor real-time monitors the wheel speeds of each wheel of the vehicle; The inertial sensor provides acceleration and angular velocity data, uses a physical model to predict the current position and velocity, and predicts the state at the next moment based on the current information; the absolute position and velocity information provided by the satellite receiver is called the observation value; the prediction covariance matrix reflects the prediction error of the inertial sensor, and the measurement covariance matrix reflects the error of GNSS measurement; When fusing the data of the three sensors, it determines their respective credibility. The Kalman filter calculates the Kalman gain, dynamically adjusts the weights of the two based on the uncertainty of the predicted value and the observation value, and generates a more accurate optimal estimate by weighted combination of the prior estimate of the inertial sensor and the observation value of the satellite receiver, representing the best system state after fusion at the current moment, including position and velocity information.

[0010] Step S2: The brake pedal state detection module real-time monitors whether the brake pedal is depressed during vehicle driving: No, go to step S1; Yes, continue to the next step; Step S3: The braking performance calculation module calculates the braking performance parameters, including the braking time, braking distance, and braking deceleration for each braking test; The process of calculating the braking distance is as follows: Assume that the braking test starts at time t0, and a calculation is performed every Δt. Then, for the time period [ti, ti+1], the displacement increment Δxi is given by the following formula: ; Substitute the displacement increment Δxi of each time period within the braking cycle into the following formula to obtain the braking distance Xn: ; Initial displacement X 0is 0, and after simplification, the calculation formula for the braking distance Xn is obtained: ; Calculation process of braking deceleration: Mean fully developed deceleration MFDD: MFDD = ((Vb)² – (Ve)²) / (25.92 * (Se – Sb)); Where: v: Initial braking speed of the test vehicle, km / h; Vb: Experimental vehicle speed of 0.8v, km / h; Ve: Experimental vehicle speed of 0.1v, km / h; Sb: Traveling distance of the experimental vehicle from v to Vb, unit m; Se: Traveling distance of the experimental vehicle from v to Ve, unit m; 25.92 is a conversion coefficient used to convert the speed square difference (Vb² - Ve²) in km / h and the difference in braking distance (Se - Sb) in m into m / s², which is the unit of deceleration; Calculation process of braking time: Assume that the braking test starts at time t0, and calculations are performed every Δt. After N cycles, the braking test ends. Then the calculation formula for braking time is as follows: ; Where: Δt is the calculation period, unit s; N is the number of cycles; Step S4: The error compensation module compensates for the error caused by the inconsistency between the braking trigger speed and the target speed, and the braking performance parameters are output through the communication interface; The empirical correction compensation formula is as follows: S = St*(Vo² / Vt²); Where: S is the corrected braking distance, unit m; St is the actual braking distance, unit m; Vo is the target braking speed, unit m / s; Vt is the actual braking speed, unit m / s; Step S5: The braking performance calculation module determines whether the braking end condition is met based on the current motion state: If not, go to step S3; if yes, the braking test result is output through the communication interface.

[0011] The present invention also provides a vehicle computer system, including a memory, a processor, and a computer program stored on the memory. The processor executes the computer program to implement the steps of the braking performance detection method based on vehicle combined inertial navigation technology.

[0012] Compared with traditional friction wheels or single sensors used, the superior effects of the present invention are: 1) High detection accuracy: By fusing multiple sensors, the kinematic state of the vehicle can be accurately obtained, overcoming the problem of insufficient detection accuracy of a single sensor; 2) High output frequency: The vehicle integrated inertial navigation can output the kinematic parameters of the vehicle at a high frequency, ensuring real-time detection of braking performance even under high-dynamic conditions; 3) Strong anti-external interference ability: By fusing inertial navigation and wheel speed data in the present invention, even when satellite signals are interfered with or interrupted, the kinematic state information of the vehicle can still be accurately output, ensuring the continuity and reliability of braking performance detection; 4) Wide range of applicable scenarios: Due to relying on a single sensor, it can maintain stable detection accuracy in various complex environments and is applicable to braking performance tests in various scenarios such as cities, highways, and tunnels; 5) Improved accuracy of braking performance parameters and reliability of the detection device: The error compensation module can compensate for errors caused by the delay in braking triggering and the errors generated by the inconsistency between the actual triggering speed and the target speed of the vehicle, making the braking performance parameters closer to the true values; Through error compensation, the present invention can still output stable and reliable braking performance parameters in the face of different braking conditions and environmental changes, improving the overall detection accuracy and credibility. Description of the Drawings

[0013] The specification drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is the flowchart of the present invention; Figure 2 is the circuit principle block diagram of the detection device in the specific embodiment of the present invention; Figure 3 is the flowchart of the detection method in the specific embodiment of the present invention; Figure 4 is the schematic diagram of the speed change comparison between the specific embodiment of the present invention and competing products; Explanation of the reference numerals in the drawings: 1 - Satellite receiver; 2 - Accelerometer; 3 - Angular velocity meter; 4 - Wheel speed meter; 5 - Braking sensor; 6 - Memory; 7 - Communication peripheral; 8 - Computing unit. Detailed Embodiments

[0014] The embodiments of the present invention will be described in detail below with reference to the drawings.

[0015] As Figure 2As shown in the figure, the present invention provides a braking performance detection device based on vehicle combined inertial navigation technology, including: A braking sensor 5 that monitors in real time the state change of the brake pedal during vehicle driving, captures the start time and end time of the braking process, and outputs them to the calculation unit 8; when the brake pedal is pressed or released, the braking sensor 5 captures the change in the action state, converts the non-electrical signal into an electrical signal, and inputs it into the calculation unit 8; through these signals, the start time and end time of the braking process are accurately captured; An inertial sensor, including an accelerometer 2 and an angular velocity meter 3, which detects the kinematic state of the vehicle in real time, obtains the speed, acceleration, and angular velocity of the vehicle, and outputs them to the calculation unit 8; A wheel speed meter 4, as a supplement and constraint condition for the satellite receiver and inertial sensor, monitors the wheel speeds of each wheel of the vehicle in real time and outputs them to the calculation unit 8; A satellite receiver 1 that monitors the original satellite data of the vehicle and outputs it to the calculation unit 8; A calculation unit 8 that performs acquisition, filtering, and fusion calculation of the original data. After obtaining the state data of the brake pedal and the kinematic state data of the vehicle, it performs data resolution, and calculates the braking distance, braking time, and braking deceleration during the braking process according to the start time and end time of braking; The calculation unit 8 includes an error compensation unit that compensates for the errors in the braking performance parameters caused by the delay in braking triggering and the inconsistency between the actual triggering speed and the target speed of the vehicle; A memory 6 for storing log data, A communication peripheral 7 through which the braking performance parameters are output.

[0016] The present invention also provides a vehicle equipped with the braking performance detection device based on vehicle combined inertial navigation technology.

[0017] As Figure 1 and Figure 3 shown, the present invention provides a braking performance detection method based on vehicle combined inertial navigation technology, including the following steps: Step S1: The accelerometer 2 and the angular velocity meter 3 detect the kinematic state of the vehicle in real time, obtain the speed, acceleration, and angular velocity of the vehicle; the satellite receiver 1 monitors the original satellite data of the vehicle; the wheel speed meter 4 monitors the wheel speeds of each wheel of the vehicle in real time; Output the above vehicle motion state data to the calculation unit 8 through multi-sensor fusion; Step S2: The braking sensor 5 detects the state of the brake pedal during vehicle driving in real time and determines whether the brake pedal is pressed: No, go to step S1; Yes, continue to the next step; Step S3: The calculation unit 8 calculates the braking performance parameters, including the braking time, braking distance, and braking deceleration for each braking test. Braking distance calculation process: Assume that the braking test starts at time t0, and calculations are performed every Δt. For the time period [ti, ti+1], the displacement increment Δxi is given by the following formula: ; Substitute the displacement increment Δxi for each time period within the braking cycle into the following formula to obtain the braking distance Xn: ; The initial displacement X 0 is 0, and after simplification, the calculation formula for the braking distance Xn is obtained: ; The braking distance calculated by the above braking distance calculation process is accurate, has wide applicability, the data is continuous and complete, and can more accurately evaluate the braking performance; Braking deceleration calculation process: Mean fully developed deceleration MFDD: MFDD = ((Vb)² – (Ve)²) / (25.92 * (Se – Sb)); Where: v: Initial braking speed of the test vehicle, km / h; Vb: Experimental vehicle speed of 0.8v, km / h; Ve: Experimental vehicle speed of 0.1v, km / h; Sb: Travel distance of the experimental vehicle from speed v to Vb, unit m; Se: Travel distance of the experimental vehicle from speed v to Ve, unit m; 25.92 is a conversion coefficient used to convert the speed square difference (Vb² - Ve²) in km / h and the difference in braking distance (Se - Sb) in m to m / s², where m / s² is the unit of deceleration; it fully considers the relationship between the experimental vehicle speed and the travel distance, more realistically reflects the change in deceleration during the braking process of the vehicle, has wide applicability, and provides a reliable basis for evaluating the braking performance.

[0018] Braking time calculation process: Assume that the braking test starts at time t0, and calculations are performed every Δt. After N cycles, the braking test ends. Then the braking time calculation formula is as follows: ; Where: Δt is the calculation cycle, unit s; N is the number of cycles.

[0019] Step S4: The error compensation module compensates for the error caused by the inconsistency between the braking trigger speed and the target speed, and the braking performance parameters are output through the communication interface. The empirical correction compensation formula is as follows: S = St*(Vo² / Vt²); Where: S is the corrected braking distance, unit m; St is the actual braking distance, unit m; Vo is the target braking speed, unit m / s; Vt is the actual braking speed, unit m / s. By considering the difference between the target braking speed and the actual braking speed, the actual braking distance is corrected, so as to obtain a braking distance closer to the real situation, and the accuracy of the braking distance data is improved in a cost-effective way.

[0020] From Figure 4 the speed change schematic diagram, it can be seen that the speed measurement errors and noises of competing products detected by a single sensor are large. The present invention effectively corrects the high-frequency noises and errors in the speed measurement values by using the multi-sensor data fusion method, so it has higher detection accuracy and stronger anti-interference ability than competing products with a single sensor.

[0021] Step S5: The calculation unit 8 determines whether the braking end condition is satisfied according to the current motion state: if not, go to step S3; if yes, the braking test result is output through the communication interface.

[0022] The braking performance parameters reflect the braking performance of the vehicle and are used to evaluate the braking effect of the vehicle under different conditions.

[0023] The present invention also provides a vehicle computer system, including a memory, a processor, and a computer program stored on the memory, and the processor executes the computer program to implement the steps of the braking performance detection method based on the vehicle-mounted integrated inertial navigation technology.

[0024] By integrating a variety of sensor technologies, the present invention more accurately monitors and evaluates the braking performance of the vehicle, has a broad application prospect, especially plays an important role in the testing of autonomous driving and active safety systems, and provides accurate and reliable testing and evaluation for the active safety and automatic emergency braking system AEB as well as the vehicle braking performance test.

[0025] In the test of the Automatic Emergency Braking for Rear-end Collision (AEB CCR) in the Automatic Emergency Braking System (AEB) of the active safety part in the "C-NCAP Management Rules" (China New Car Assessment Program), the following scenarios are included: the scenario of the leading vehicle being stationary, with the leading vehicle stationary and the following vehicle having speeds of 20 km / h, 30 km / h, and 40 km / h, and test scenarios with offset ratios of ±50% and 100%; the scenario of the leading vehicle moving slowly, with the leading vehicle at 20 km / h and the following vehicle having speeds of 20 km / h, 30 km / h, and 40 km / h, and test scenarios with offset ratios of ±50% and 100%. The present invention can be extremely conveniently and quickly applied to these test scenarios to accurately and reliably evaluate the braking performance.

[0026] The foregoing are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A braking performance detection device based on vehicle combined inertial navigation technology, comprising: The brake pedal state detection module includes a brake sensor, which monitors the state changes of the brake pedal during vehicle movement in real time, captures the start and end time of the braking process, and outputs it to the brake performance solution module; The vehicle-use combined inertial navigation module detects the vehicle's kinematic state in real time and outputs it to the braking performance calculation module; The braking performance calculation module obtains the state data of the brake pedal and the state data of the vehicle kinematics, and calculates the braking performance parameters according to the start and end time of braking; The error compensation module obtains the braking performance parameters and compensates for the braking performance parameter errors caused by the delay in braking triggering and the inconsistency between the actual triggering speed of the vehicle and the target speed.

2. The braking performance detection device based on vehicle combined inertial navigation technology according to claim 1 is characterized in that: The vehicle-used combined inertial navigation module comprises an inertial sensor, a satellite receiver and a wheel speed sensor.

3. The braking performance detection device based on vehicle combined inertial navigation technology according to claim 1 is characterized in that: Also includes Storage module, storing log data; The communication peripheral module provides an interface for external interaction.

4. A braking performance detection method based on vehicle combined inertial navigation technology, comprising the following steps: Step S1, the vehicle combined inertial navigation module detects the kinematic state of the vehicle in real time and outputs it to the braking performance solution module; Step S2: The brake pedal status detection module monitors in real time whether the brake pedal is pressed while the vehicle is driving: No, go to step S1; Yes, proceed to the next step; Step S3, the braking performance calculation module calculates the braking performance parameters, including the braking time, braking distance, and braking deceleration in each detection cycle; Step S4: the error compensation module compensates for the error caused by the inconsistency between the braking trigger speed and the target speed, and the braking performance parameters are output via the communication interface.

5. The braking performance detection method based on vehicle combined inertial navigation technology according to claim 4 is characterized in that: The vehicle-used combined inertial navigation module specifically comprises: an inertial sensor for real-time detection of the vehicle's posture, acceleration, and angular velocity; a satellite receiver for providing the vehicle's original satellite data; and a wheel speed sensor for real-time monitoring of the wheel speed of each wheel of the vehicle.

6. The braking performance detection method based on vehicle combined inertial navigation technology according to claim 4 is characterized in that: The step S5 is also included, the braking performance calculation module determines whether the braking end condition is met according to the current motion state: No, go to step S3; Yes, the braking test result is output through the communication interface and ends.

7. A vehicle, characterized in that: The vehicle is equipped with a braking performance detection device based on vehicle combined inertial navigation technology according to any one of claims 1 to 3.

8. A vehicle computer system, comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the braking performance detection method based on vehicle combined inertial navigation technology as described in any one of claims 4-6.

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