Air suspension-based curb detection method and system

Abstract

The application relates to a curb detection method based on an air suspension, comprising the following steps: acquiring suspension height signals at each wheel of a vehicle and a vehicle body posture angle, calculating posture compensation amounts caused by vehicle body tilting at each wheel based on the vehicle body posture angle, acquiring corrected heights after eliminating the influence of vehicle body tilting based on the suspension height signals at each wheel and the corresponding posture compensation amounts, and comparing the differences between the left and right wheels in the same shaft according to the corrected heights of each wheel. The application quantitatively deducts the height change caused by the vehicle body posture tilting from the wheel height signals from the physical mechanism level, and then compares the differences between the left and right wheels in the same shaft according to the corrected heights of each wheel, so that the overall road tilting and the wheel riding on the curb have clear numerical separability in the corrected height space, and the false positives caused by the road tilting and the false negatives caused by the curb contact are avoided.

Description

Technical Field

[0001] This invention relates to the field of automotive electronic control technology, specifically to a curb detection method and system based on air suspension. Background Technology

[0002] The Electronically Controlled Air Suspension (ECAS) system controls the inflation and deflation of four independent airbags in each wheel to achieve functions such as vehicle height adjustment, attitude control, and leveling. When a vehicle is parked on a curb or uneven surface, one or more wheels may mount the curb or other protrusions, causing the relative position of the wheels and the vehicle body to deviate from the normal coplanar state. If the suspension system performs active height adjustment (such as automatic leveling) in this state, it may lead to a risk of vehicle rollover or damage to the airbags / mechanical structures. Therefore, accurately identifying curb contact when the vehicle is stationary and suppressing inappropriate active suspension adjustments accordingly is an important requirement for ensuring parking safety.

[0003] Existing curb detection methods mainly include vision / radar detection schemes based on cameras or radar, and detection schemes based on absolute threshold comparison of suspension height signals. Among them, vision / radar schemes require additional sensor hardware, which is costly and greatly affected by environmental factors such as weather and lighting, and the system calibration is complex. Schemes based on absolute threshold of suspension height compare the height values ​​of each wheel with a fixed threshold, which makes it difficult to distinguish between normal height changes caused by the overall tilt of the road surface and abnormal height changes caused by individual wheels riding on the curb, which is prone to misjudgment. In addition, residual shaking of the vehicle body may exist after the vehicle is parked, and passengers getting in and out of the vehicle or loading and unloading luggage will also cause changes in suspension height. All of the above factors may interfere with the accuracy of curb detection, resulting in unreliable detection results. Therefore, there is an urgent need for a curb detection method that does not require additional sensor hardware and can eliminate interference from vehicle body tilt and various transient conditions, so as to accurately identify whether the vehicle is in contact with the curb. Summary of the Invention

[0004] This application provides a curb detection method and system based on air suspension to solve the above-mentioned problems.

[0005] In a first aspect, embodiments of this application provide a curb detection method based on air suspension, comprising the following steps: The suspension height signal and vehicle attitude angle at each wheel of the vehicle are obtained. The attitude compensation amount caused by vehicle tilt at each wheel is calculated based on the vehicle attitude angle. Based on the suspension height signal and the corresponding attitude compensation amount at each wheel, the corrected height after eliminating the effect of vehicle tilt is obtained. Based on the corrected height of each wheel, the difference between the left and right wheels on the same axle is compared, and the result of the difference comparison is used to determine whether to generate a curb detection signal. When a curb detection signal is generated, it is detected whether the vehicle body attitude angle meets the preset stability condition, whether the suspension height change rate meets the preset quasi-static condition, and whether the vehicle meets the stationary state condition. When all three conditions are met, it is determined that the vehicle is in a curb contact state and a curb confirmation signal is generated.

[0006] In conjunction with the first aspect, in one embodiment, the vehicle attitude angle includes the vehicle pitch angle and the vehicle roll angle.

[0007] In conjunction with the first aspect, in one implementation, the attitude compensation amount at each wheel caused by vehicle tilt is calculated based on the vehicle attitude angle, specifically including: The structural dimensions of the vehicle are calculated based on the sine functions of the vehicle's pitch angle and roll angle, including the wheelbase and track width.

[0008] In conjunction with the first aspect, in one implementation, the corrected height after eliminating the effect of vehicle body tilt is obtained based on the suspension height signal at each wheel and the corresponding attitude compensation amount. Specifically, this is obtained by calculating the sum of the suspension height signal at each wheel and the corresponding attitude compensation amount.

[0009] In conjunction with the first aspect, in one implementation, a difference comparison is made between the left and right wheels on the same axle based on the corrected height of each wheel, and a decision is made on whether to generate a curb detection signal based on the result of the difference comparison, specifically including: Calculate the absolute values ​​of the corrected height difference between the left and right front axle wheels and the corrected height difference between the left and right rear axle wheels respectively; The absolute value of each axis is compared with the preset detection threshold. When the absolute value of any axis is greater than or equal to the preset detection threshold, a height anomaly is determined to exist, and a curb detection signal is generated.

[0010] In conjunction with the first aspect, in one implementation, detecting whether the vehicle body attitude angle meets a preset stability condition specifically includes: Calculate the absolute values ​​of the changes in vehicle pitch angle and vehicle roll angle between the current sampling time and the previous sampling time, respectively. The number of sampling periods in which the absolute value of the pitch angle change is continuously less than a preset limit, and the number of sampling periods in which the absolute value of the roll angle change is continuously less than a preset limit are recorded. When both the first sampling period number and the second sampling period number are greater than or equal to a preset number threshold, the stability condition is determined to be met.

[0011] In conjunction with the first aspect, in one implementation method, detecting whether the rate of change of suspension height meets a preset quasi-static condition specifically includes: The suspension vertical velocity of each wheel is obtained based on the suspension height signal of each vehicle. Determine whether the absolute value of the vertical suspension velocity of each wheel is less than a preset vertical velocity threshold. If so, then the preset quasi-static conditions are met.

[0012] In conjunction with the first aspect, in one implementation method, detecting whether the vehicle meets the stationary state condition specifically includes: Acquire vehicle speed signal; Determine whether the speed signal is 0; If so, then the static state condition is satisfied.

[0013] In conjunction with the first aspect, in one embodiment, the method further includes a stabilization step, the stabilization step comprising: When all three conditions are met simultaneously and the duration of the condition meets the preset first time threshold, a curb confirmation signal is generated. When any one of the three conditions is not met and the duration of the condition is met reaches the preset second time threshold, the curb confirmation signal will be set to invalid.

[0014] Secondly, embodiments of this application provide a system for a curb detection method based on air suspension, comprising: The data acquisition module is used to acquire suspension height signals at each wheel of the vehicle and the vehicle body attitude angle. The generation module is used to calculate the attitude compensation amount caused by the vehicle tilt at each wheel based on the vehicle attitude angle, and to obtain the corrected height after eliminating the influence of vehicle tilt based on the suspension height signal at each wheel and the corresponding attitude compensation amount; to compare the difference between the left and right wheels on the same axle based on the corrected height of each wheel, and to determine whether to generate a curb detection signal based on the result of the difference comparison. The detection module is used to detect whether the vehicle body attitude angle meets the preset stability condition, whether the suspension height change rate meets the preset quasi-static condition, and whether the vehicle meets the stationary state condition when the curb detection signal is generated. When all three conditions are met, the vehicle is determined to be in the curb contact state and a curb confirmation signal is generated.

[0015] The beneficial effects of the technical solutions provided in this application include: 1. This application calculates the attitude compensation amount at each wheel due to vehicle tilt based on the vehicle attitude angle, and superimposes the suspension height signal at each wheel with the corresponding attitude compensation amount to obtain the corrected height after eliminating the influence of vehicle tilt. Through the above attitude compensation processing, the height change caused by vehicle tilt is quantitatively deducted from the height signal of each wheel from the physical mechanism level. On this basis, the difference between the left and right wheels on the same axle is compared according to the corrected height of each wheel, so that the two scenarios of overall road tilt and wheel riding on the curb have clear numerical separability in the corrected height space, thus avoiding false alarms caused by road tilt and false alarms caused by curb contact.

[0016] 2. After generating the curb detection signal based on coaxial difference comparison, the system further checks whether the vehicle body attitude angle meets preset stability conditions, whether the suspension height change rate meets preset quasi-static conditions, and whether the vehicle is stationary. A curb confirmation signal is only generated when all three conditions are met simultaneously. Attitude stability verification eliminates interference from residual vehicle body sway after parking; quasi-static suspension verification eliminates interference from normal usage scenarios such as passenger entry / exit and luggage loading / unloading; and vehicle stationary status confirmation limits the detection function to parking conditions, avoiding false triggers caused by road bumps during vehicle movement. This multi-condition joint verification mechanism effectively reduces the false trigger rate and ensures the reliability of the detection results.

[0017] 3. This application completes all signal inputs for curb detection by acquiring suspension height signals at each wheel and vehicle attitude angle. The suspension height sensor and inertial measurement unit are existing standard components of electronically controlled air suspension systems, requiring no additional sensor hardware such as cameras or radar, and without altering the existing system architecture or wiring harness layout. This solution can be directly deployed on mass-produced vehicles via software upgrades, demonstrating good compatibility and widespread application value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram illustrating the main steps of the present invention; Figure 2 This is a flowchart of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] Example 1: Please see Figure 1 and Figure 2 Embodiment 1 of this application provides a curb detection method based on air suspension, which includes the following steps: S1. Obtain the suspension height signal and vehicle attitude angle at each wheel of the vehicle. Calculate the attitude compensation amount caused by vehicle tilt at each wheel based on the vehicle attitude angle. Obtain the corrected height after eliminating the influence of vehicle tilt based on the suspension height signal and the corresponding attitude compensation amount at each wheel. In this embodiment, the vehicle attitude angle includes the vehicle pitch angle and the vehicle roll angle; Suspension height signal: acquired through the suspension height sensors of each wheel; Vehicle attitude angles: obtained through the vehicle inertial measurement unit; where, a vehicle pitch angle > 0 indicates that the front of the vehicle is raised, and a vehicle roll angle > 0 indicates that the left side of the vehicle is raised; Attitude compensation calculation: In this embodiment, the attitude compensation amount is calculated based on the vehicle's structural dimension parameters and the sine functions of the vehicle's pitch angle and roll angle. The structural dimension parameters include the wheelbase and track width, which are specifically expressed by the following formula: ; ; ; ; in, The vehicle body pitch angle, The body roll angle, Wheelbase Wheelbase; Those skilled in the art will understand that and These are fixed structural constants determined at the vehicle's factory and pre-programmed into the ECU; the sign of the above formula is determined by the positive directions of the pitch and roll angles: when the front of the vehicle is raised ( When φ > 0, the compensation amount of the two front axle wheels is negative (relative compression of the suspension) and the compensation amount of the two rear axle wheels is positive (relative extension of the suspension); when the left side of the vehicle body is lifted (φ > 0), the compensation amount of the two left wheels is negative and the compensation amount of the two right wheels is positive.

[0022] Corrected height: The suspension height signals at each wheel are superimposed with the corresponding attitude compensation amounts to obtain the corrected height after eliminating the effects of vehicle roll, which is expressed by the following formula: ; ; ; ; in, , , , These are the suspension height signals for the front left, front right, rear left, and rear right wheels, respectively. , , , These are the attitude compensation amounts for the corresponding wheels; The corrected height characterizes the equivalent height of each wheel suspension relative to an ideal level vehicle body after eliminating the effects of vehicle pitch and roll. When the vehicle is parked on a sloping road surface but all four wheels are in normal contact with the ground (coplanar), the corrected height of the left and right wheels on the same axle is theoretically equal. When a wheel rides on a curb or other protrusion that disrupts the coplanarity of the four wheels, the corrected height will show a significant difference between the left and right wheels on the same axle.

[0023] As an alternative, when both the vehicle pitch angle and roll angle are small (e.g., less than 10°), small-angle approximations sinθ≈θ and sinφ≈φ (angles expressed in radians) can be used to replace the sine function calculation, thereby reducing the trigonometric function calculation overhead of the ECU. It is understood that this approximation scheme is suitable for passenger vehicles whose main operating conditions are urban roads and highways, reducing the computational load while ensuring detection accuracy. The specific application can be selected according to the requirements.

[0024] S2. Based on the correction height of each wheel, compare the differences between the left and right wheels on the same axle, and determine whether to generate a curb detection signal based on the comparison results. In this embodiment, step S2 specifically includes: Calculate the absolute values ​​of the corrected height difference between the left and right front axle wheels and the corrected height difference between the left and right rear axle wheels respectively, that is: ; ; The absolute values ​​of each axis are compared with the preset detection thresholds. Compare; like ≥ or ≥ If the height anomaly is detected, a curb detection signal is generated; otherwise, no curb detection signal is generated, and the process returns to step S1 to continue monitoring. In this embodiment, the detection threshold As calibrable parameters, they are matched and set according to the suspension travel, wheel alignment parameters and curb height standards of different vehicle models.

[0025] By calculating the absolute value of the corrected height difference between the left and right wheels on the same axle and comparing this difference with a preset detection threshold, a quantitative assessment of the coplanarity of the four wheels is achieved. When the vehicle is parked normally on a level road or a uniformly inclined road, although the suspension height between each wheel and the body may differ due to the tilt, after the attitude compensation in step S1, the corrected height of the left and right wheels on the same axle is basically the same, and the difference is close to zero. When a wheel on one side rides on the curb or presses on a protrusion, the height of that wheel relative to the body is abnormally raised, and the corrected height difference between the left and right wheels on the same axle will increase significantly. When this difference exceeds the preset threshold, it is determined that there is a height abnormality, thereby triggering the generation of the curb detection signal. This step, by performing coaxial comparison in the corrected height space, effectively eliminates common-mode interference caused by vehicle body tilt, making the detection results depend solely on whether the four wheels are coplanar, thus providing an accurate front-end judgment basis for subsequent confirmation of curb contact status.

[0026] S3. When generating a curb detection signal, check whether the vehicle body attitude angle meets the preset stability condition, whether the suspension height change rate meets the preset quasi-static condition, and whether the vehicle meets the stationary state condition. When all three conditions are met, determine that the vehicle is in curb contact state and generate a curb confirmation signal.

[0027] After the conditions of height anomaly are met, this embodiment also includes performing attitude stability verification, suspension quasi-static verification, and vehicle stationary state verification. Specifically: ① Attitude stability verification: In response to the judgment result of height anomalies, to avoid the transient fluctuations in height difference caused by residual body sway (pitch and roll have not yet decayed to a steady state) during vehicle parking being misjudged as roadside curbs, this embodiment introduces stability verification based on vehicle attitude angles to eliminate misjudgments caused by residual body sway during vehicle parking. Specifically: Calculate the absolute value of the change in pitch angle between the current sampling time and the previous sampling time. and the absolute value of the change in roll angle ; Will , With preset limit Compare; statistics consecutively less than The number of the first sampling period, and consecutively less than The number of the second sampling period; When both the first sampling period and the second sampling period are greater than or equal to the preset number of times threshold When the condition is met, it is determined that the stability condition is satisfied.

[0028] In this embodiment, the preset limit value This is used to characterize the maximum fluctuation range of the allowable single change in vehicle attitude angle. It measures whether the change in vehicle pitch angle or vehicle roll angle between adjacent sampling periods is within an acceptable stable range. When the change in attitude angle is less than this limit, it indicates that the instantaneous sway of the vehicle in that direction is small and the vehicle body tends to be stable. When the change is greater than or equal to this limit, it indicates that there is still obvious sway of the vehicle body, which may interfere with height detection. Preset number of times threshold The minimum number of sampling periods required to continuously maintain a stable vehicle body attitude angle is used to characterize this, i.e., the duration requirement for measuring attitude stability. Since the change in attitude angle within a single sampling period is less than the limit, it only indicates that the instantaneous sway is small and does not mean that the vehicle body is completely stable. Therefore, it is necessary to count the number of sampling periods that continuously meet the stability condition. Only when the number of continuously stable periods reaches a certain threshold... Only when the vehicle body attitude truly reaches a stable state is the determination made. This threshold is used to eliminate short-term stability illusions caused by occasional disturbances, ensuring the reliability of the stability determination. Those skilled in the art will understand that The specific value needs to comprehensively consider the vibration characteristics of the vehicle suspension system, the typical attenuation amplitude of residual sway after parking, and the sensor noise level, in order to accurately distinguish between normal swaying and unstable states, and avoid misjudging the curb due to an excessively large limit or failing to meet stability conditions due to an excessively small limit. The specific value needs to be set in conjunction with the sampling period. For example, with a sampling period of 10ms, =10 corresponds to 100ms of continuous stability. This duration needs to be sufficient to cover the decay time of residual shaking of the vehicle body after parking, while also taking into account the detection response speed to avoid excessive confirmation time for curb detection due to an excessively large threshold.

[0029] The above two parameters and Together, they constitute the judgment criteria for attitude stability verification, among which The stable amplitude condition for a single sampling is determined. The determination of the required duration of stability, combined with the requirement of stability, can effectively distinguish between brief signal fluctuations and true attitude stability.

[0030] ②Suspension quasi-static verification: In addition, to avoid the slow changes in suspension height caused by normal use scenarios such as passengers getting on and off the vehicle, loading and unloading luggage or cargo being misjudged as curb contact, this embodiment introduces a quasi-static suspension verification to eliminate interference with the test results during dynamic changes in the suspension. Specifically: The vertical speed of the suspension of each wheel is obtained based on the suspension height signal of each wheel. In this embodiment, the vertical speed is obtained by performing a differential calculation on the measured suspension height of each wheel, that is, the difference between the suspension height at the current sampling moment and the suspension height at the previous sampling moment divided by the sampling period. Determine whether the absolute value of the vertical suspension velocity of each wheel is less than a preset vertical velocity threshold. When the absolute value of the vertical velocity of all four wheels is less than the preset vertical velocity threshold, the suspension is determined to be in a quasi-static state.

[0031] In this embodiment, the preset vertical velocity threshold is used to characterize the upper limit of the allowable rate of change of suspension height, that is, to measure whether the rate of change of suspension height of each wheel over time is within an acceptable static range. When the absolute value of the vertical velocity of the wheel is less than the threshold, it indicates that the change in suspension height at that wheel within the sampling period is small, and the suspension is basically at rest or quasi-static. When the absolute value of the vertical velocity is greater than or equal to the threshold, it indicates that there are still obvious dynamic changes in the suspension, such as when passengers are getting on or off the vehicle or luggage is being loaded or unloaded. At this time, the suspension height has not yet stabilized, and it is not appropriate to make a final determination of the curb contact state. Those skilled in the art will understand that the specific value of the preset vertical speed threshold needs to take into account the stiffness and damping characteristics of the suspension system, the sampling frequency, and the noise level of the suspension height signal when the vehicle is stationary. With a sampling period of 10ms, the preset vertical speed threshold can be calibrated according to the resolution and noise characteristics of the suspension height sensor. The suspension characteristics of different models are different, and its specific value is calibrated according to the actual vehicle test results in order to achieve a balance between detection reliability and response speed.

[0032] ③ Vehicle stationary state verification: To avoid misjudging roadside contact due to a sudden increase in the height difference between the left and right wheels on the same axle caused by bumps or speed bumps during vehicle operation, this embodiment also introduces vehicle stationary state verification to ensure that roadside detection only takes effect when the vehicle is stationary.

[0033] In this embodiment, the electronic control unit obtains the vehicle speed signal through the CAN bus and determines whether the vehicle speed signal is zero. When the vehicle speed is zero, it is determined that the vehicle is stationary.

[0034] Those skilled in the art will understand that, in addition to the vehicle speed signal, alternative embodiments can also determine that the vehicle is stationary by having all four wheel speed signals be zero, or by combining the parking brake status signal with the vehicle speed signal. All of the above methods fall within the protection scope of this invention.

[0035] When the above three conditions of attitude stability verification, suspension quasi-static verification and vehicle stationary state verification are met simultaneously, it is determined that the vehicle is indeed in contact with the curb, rather than a temporary height abnormality caused by vehicle body swaying, occupant activity or driving conditions, and a curb confirmation signal is generated at this time.

[0036] In summary, the above three-fold judgment mechanism effectively reduces the interference of residual vehicle body sway after parking on the test results through posture stability verification; eliminates the interference of normal use scenarios such as passenger getting in and out of the vehicle and loading and unloading luggage through suspension quasi-static verification; limits the detection function to parking conditions through vehicle stationary state confirmation, avoiding false triggering caused by road bumps during vehicle movement; and ensures the reliability of the test results by effectively reducing the false trigger rate through the multi-condition joint verification mechanism.

[0037] In addition, this embodiment also includes image stabilization processing, specifically: To further improve the stability and anti-interference ability of the detection results and avoid frequent flipping of the road edge confirmation signal due to transient signal fluctuations or critical states at threshold boundaries, this embodiment preferably includes a de-jitter processing step before and after generating the road edge confirmation signal. Specifically: A: When the above three conditions are met simultaneously and the duration of the condition meets the preset first time threshold, a curb confirmation signal is generated. Specifically, when all three conditions are met simultaneously and the duration reaches a preset first time threshold, a curb confirmation signal is generated; if any condition is not met during the duration, the time is reset and the duration is recalculated.

[0038] B: When any of the three conditions is not met and the duration of the condition is met reaches the preset second time threshold, the curb confirmation signal will be set to invalid.

[0039] Specifically, in the exit direction, when a curb confirmation signal has been generated and any one of the three conditions is not met, if the duration reaches a preset second time threshold, the curb confirmation signal will be set to invalid; if all three conditions are met again during the accumulation process, the curb confirmation signal will remain valid.

[0040] In this embodiment, both the first time threshold and the second time threshold are independently calibrable parameters. As a preferred option, the first time threshold is set to a shorter value (e.g., on the order of 100ms) to ensure a rapid response to actual curb contact. The second time threshold is set to a longer value (e.g., on the order of 1000ms) to avoid frequent state reversals caused by short-term signal fluctuations, thereby improving the stability and anti-interference capability of the system.

[0041] Those skilled in the art will understand that the specific values ​​of the first and second time thresholds can be calibrated based on real-vehicle test results and application scenario requirements. In scenarios requiring rapid response, the activation time threshold can be shortened; in scenarios with high anti-interference requirements, the exit time threshold can be extended.

[0042] When a curb confirmation signal is sent to the suspension controller, the suspension controller, based on this signal, suppresses the active height adjustment function, including but not limited to: disabling automatic leveling, disabling active height adjustment, and maintaining the current suspension height. Specifically: The suspension controller prohibits the execution of any inflation / deflation control commands for the independent airbags at the four wheels to prevent the vehicle's center of gravity from shifting, overturning, or damage to the suspension airbags and mechanical structure due to suspension height adjustment while in contact with the curb. When the curb confirmation signal or curb detection output mark is set to invalid, the suspension controller resumes normal height adjustment function. In addition, the electronic control unit can also issue a prompt to the driver through the instrument panel, central control screen or buzzer, informing the driver that the vehicle is currently in contact with the curb and suggesting that the surrounding environment be checked for safety before starting the vehicle.

[0043] Those skilled in the art will understand that during the effective period of the curb confirmation signal output, if the driver manually operates the vehicle to move away from the curb, the suspension height of each wheel gradually returns to normal, the height difference between the left and right wheels on the same axle falls back below the preset detection threshold, the curb confirmation signal is cleared, and the suspension controller resumes its normal height adjustment function without manual intervention.

[0044] The threshold parameters involved in the above embodiments—including but not limited to preset detection threshold, preset limit, preset number of times threshold, preset vertical velocity threshold, first time threshold, and second time—are all independently calibrable parameters. They can be matched and set according to different vehicle models and usage scenarios. They can adapt to vehicle models with different wheelbases, track widths, suspension travels, and sensitivity requirements for different curb height standards and usage scenarios without modifying the algorithm logic. Furthermore, the suspension height sensor and inertial measurement unit are existing standard components of electronically controlled air suspension systems, requiring no additional sensor hardware such as cameras or radar, and without changing the existing system architecture and wiring harness layout. This solution can be directly deployed on mass-produced vehicle models through software upgrades, demonstrating good compatibility and promotional value.

[0045] Example 2: Embodiment 2 of this application provides a system for curb detection based on air suspension, which includes a data acquisition module, a generation module, and a detection module. Specifically: Data acquisition module: used to acquire suspension height signals at each wheel of the vehicle and vehicle attitude angle; it includes a suspension height acquisition unit and a vehicle attitude acquisition unit; The suspension height acquisition unit is used to acquire the suspension height signal of each wheel. In this embodiment, the suspension height acquisition unit is a suspension height sensor installed at each wheel, which sends the suspension height signal of each wheel to the electronic control unit through the CAN bus at a preset period. The vehicle attitude acquisition unit is used to acquire the vehicle attitude angle. In this embodiment, the vehicle attitude acquisition unit is an inertial measurement unit (IMU) installed near the center of gravity of the vehicle body. It also provides vehicle pitch angle and vehicle roll angle signals at a preset period. The suspension height sensor and the inertial measurement unit are both existing standard components of the electronically controlled air suspension system, and no additional sensor hardware is required.

[0046] The generation module is used to perform the following processing based on the suspension height signal and vehicle attitude angle obtained by the data acquisition module: calculate the attitude compensation amount caused by vehicle tilt at each wheel based on the vehicle attitude angle; obtain the corrected height after eliminating the influence of vehicle tilt based on the suspension height signal and the corresponding attitude compensation amount at each wheel; compare the difference between the left and right wheels on the same axle based on the corrected height of each wheel; and determine whether to generate a curb detection signal based on the result of the difference comparison. The specific signal processing method of the generation module is exactly the same as steps S1 and S2 in Embodiment 1, and will not be repeated here.

[0047] The detection module is used to detect whether the vehicle body attitude angle meets the preset stability condition, whether the suspension height change rate meets the preset quasi-static condition, and whether the vehicle meets the stationary state condition when the generation module generates the curb detection signal. When all three conditions are met, the vehicle is determined to be in the curb contact state and a curb confirmation signal is generated. The specific verification method of the detection module for the three conditions is exactly the same as step S3 in Embodiment 1, and will not be repeated here.

[0048] As a preferred embodiment, the generation module and the detection module are integrated into the electronic control unit (ECU). The data acquisition module sends the acquired suspension height signal and vehicle attitude angle to the ECU. The generation module and the detection module in the ECU execute the corresponding processing steps and output a curb confirmation signal to the suspension controller. The suspension controller suppresses or restores the active height adjustment function according to the received signal.

[0049] As a specific application scenario of this application embodiment, when a vehicle is parked in a roadside parking space with a curb and the right front wheel is on the curb, the data acquisition module acquires the suspension height signal and vehicle attitude angle of each wheel in real time and sends them to the generation module. After attitude compensation, corrected height acquisition and coaxial difference comparison, the generation module determines that there is a height abnormality and generates a curb detection signal. In response to the curb detection signal, after the attitude stability verification, suspension quasi-static verification and vehicle static state verification are all satisfied, the detection module generates a curb confirmation signal and sends it to the suspension controller. The suspension controller then suppresses the active height adjustment function to ensure vehicle safety.

[0050] Those skilled in the art will understand that the air suspension-based curb detection system provided in Embodiment 2 and the air suspension-based curb detection method provided in Embodiment 1 belong to the same inventive concept. This system can realize the curb detection function by implementing the method of Embodiment 1. The specific implementation method can be found in the detailed description in Embodiment 1, and will not be repeated here.

[0051] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0052] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A curb detection method based on air suspension, characterized in that, Includes the following steps: The suspension height signal and vehicle attitude angle at each wheel of the vehicle are obtained. The attitude compensation amount caused by vehicle tilt at each wheel is calculated based on the vehicle attitude angle. Based on the suspension height signal and the corresponding attitude compensation amount at each wheel, the corrected height after eliminating the effect of vehicle tilt is obtained. Based on the corrected height of each wheel, the difference between the left and right wheels on the same axle is compared, and the result of the difference comparison is used to determine whether to generate a curb detection signal. When a curb detection signal is generated, it is detected whether the vehicle body attitude angle meets the preset stability condition, whether the suspension height change rate meets the preset quasi-static condition, and whether the vehicle meets the stationary state condition. When all three conditions are met, it is determined that the vehicle is in a curb contact state and a curb confirmation signal is generated.

2. The curb detection method based on air suspension according to claim 1, characterized in that, The vehicle attitude angles include the vehicle pitch angle and the vehicle roll angle.

3. The curb detection method based on air suspension according to claim 2, characterized in that, Based on the vehicle attitude angle, the attitude compensation amount at each wheel caused by vehicle tilt is calculated, specifically including: The structural dimensions of the vehicle are calculated based on the sine functions of the vehicle's pitch angle and roll angle, including the wheelbase and track width.

4. The curb detection method based on air suspension according to claim 1, characterized in that, Based on the suspension height signal at each wheel and the corresponding attitude compensation amount, the corrected height after eliminating the effect of vehicle body tilt is obtained. Specifically, it is obtained by calculating the sum of the suspension height signal at each wheel and the corresponding attitude compensation amount.

5. The curb detection method based on air suspension according to claim 1, characterized in that, Based on the corrected height of each wheel, the difference between the left and right wheels on the same axle is compared. Based on the result of the difference comparison, it is determined whether to generate a curb detection signal, specifically including: Calculate the absolute values ​​of the corrected height difference between the left and right front axle wheels and the corrected height difference between the left and right rear axle wheels respectively; The absolute value of each axis is compared with the preset detection threshold. When the absolute value of any axis is greater than or equal to the preset detection threshold, a height anomaly is determined to exist, and a curb detection signal is generated.

6. The curb detection method based on air suspension according to claim 2, characterized in that, Detecting whether the vehicle body attitude angle meets the preset stability conditions specifically includes: Calculate the absolute values ​​of the changes in vehicle pitch angle and vehicle roll angle between the current sampling time and the previous sampling time, respectively. The number of sampling periods in which the absolute value of the pitch angle change is continuously less than a preset limit, and the number of sampling periods in which the absolute value of the roll angle change is continuously less than a preset limit are recorded. When both the first sampling period number and the second sampling period number are greater than or equal to a preset number threshold, the stability condition is determined to be met.

7. The curb detection method based on air suspension according to claim 1, characterized in that, The test checks whether the rate of change of suspension height meets the preset quasi-static conditions, specifically including: The suspension vertical velocity of each wheel is obtained based on the suspension height signal of each vehicle. Determine whether the absolute value of the vertical suspension velocity of each wheel is less than a preset vertical velocity threshold. If so, then the preset quasi-static conditions are met.

8. The curb detection method based on air suspension according to claim 1, characterized in that, Checking whether a vehicle meets the conditions for being stationary includes: Acquire vehicle speed signal; Determine whether the speed signal is 0; If so, then the static state condition is satisfied.

9. The curb detection method based on air suspension according to claim 1, characterized in that, It also includes a stabilization step, which includes: When all three conditions are met simultaneously and the duration of the condition meets the preset first time threshold, a curb confirmation signal is generated. When any one of the three conditions is not met and the duration of the condition is met reaches the preset second time threshold, the curb confirmation signal will be set to invalid.

10. A system based on the air suspension-based curb detection method of claim 1, characterized in that, include: The data acquisition module is used to acquire suspension height signals at each wheel of the vehicle and the vehicle body attitude angle. The generation module is used to calculate the attitude compensation amount caused by the vehicle tilt at each wheel based on the vehicle attitude angle, and to obtain the corrected height after eliminating the influence of vehicle tilt based on the suspension height signal at each wheel and the corresponding attitude compensation amount; to compare the difference between the left and right wheels on the same axle based on the corrected height of each wheel, and to determine whether to generate a curb detection signal based on the result of the difference comparison. The detection module is used to detect whether the vehicle body attitude angle meets the preset stability condition, whether the suspension height change rate meets the preset quasi-static condition, and whether the vehicle meets the stationary state condition when the curb detection signal is generated. When all three conditions are met, the vehicle is determined to be in the curb contact state and a curb confirmation signal is generated.

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