Vehicle height control method and device based on rear air suspension

Abstract

This application discloses a vehicle height control method and device based on a rear air suspension, relating to the field of vehicle control technology. The method includes: when receiving a door opening signal from a target vehicle, acquiring an initial height difference between the front axle suspension and the rear axle suspension in a first direction; an air spring system is provided at the rear axle suspension, the air spring system being used to support and adjust the height of the rear axle suspension; when receiving a door closing signal from the target vehicle, acquiring a real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction, and calculating a boundary height value based on the measured height difference and the initial height difference; if the boundary height value exceeds a preset height difference threshold, controlling the air spring system to operate, thereby adjusting the current height of the rear axle suspension to achieve vehicle height control of the target vehicle. This method, based on the control of the rear air suspension, can ensure the stability of the vehicle body posture in real time and effectively.

Description

Technical Field

[0001] This invention generally relates to the field of vehicle control technology, and specifically to a vehicle height control method and device based on a rear air suspension. Background Technology

[0002] With the development of automotive intelligent technology, the active suspension system inside the vehicle, which supports the body, absorbs shocks, maintains wheel contact with the ground, and adjusts the vehicle height, can ensure that the vehicle has good ride comfort and handling stability in different road scenarios. Among them, the general active suspension system includes air suspension, which is a device that raises and lowers the chassis height by inflating and deflating the air spring system, thereby controlling the height of the vehicle body.

[0003] Existing air spring-based vehicle height adjustment systems mostly use four air springs to control vehicle height. However, in reality, some vehicles cannot have air suspension installed in the front suspension, or due to cost constraints, the vehicle cannot use a complete air suspension system, resulting in the abandonment of installing air suspension in the front suspension. Faced with these problems, the only option is to try using air suspension only in the rear suspension. Therefore, there is an urgent need for a vehicle height control method based on rear suspension air suspension. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a vehicle height control method and device based on rear air suspension.

[0005] In a first aspect, this application provides a vehicle height control method based on a rear air suspension, comprising:

[0006] When a door opening signal is received from the target vehicle, the initial height difference between the front axle suspension and the rear axle suspension in the first direction is obtained; an air spring system is provided at the rear axle suspension, which is used to support and adjust the height of the rear axle suspension;

[0007] When a door closing signal is received from the target vehicle, the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction is obtained, and the boundary height value is calculated based on the measured height difference and the initial height difference.

[0008] If the boundary height value exceeds the preset height difference threshold, the air spring system is controlled to operate, thereby adjusting the current height of the rear axle suspension to achieve vehicle height control of the target vehicle.

[0009] According to the technical solution provided in the embodiments of this application, obtaining the initial height difference between the front axle suspension and the rear axle suspension in a first direction specifically includes:

[0010] Obtain vehicle information of the target vehicle; the vehicle information includes at least the initial attitude angle and the wheelbase of the front and rear wheels;

[0011] The initial height difference is calculated based on the initial attitude angle and the wheelbase.

[0012] According to the technical solution provided in the embodiments of this application, the front axle suspension and the rear axle suspension each include a left suspension and a right suspension, and the air spring system includes two air springs respectively corresponding to the left rear axle suspension and the right rear axle suspension;

[0013] The step of obtaining the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction, and calculating the boundary height value based on the measured height difference and the initial height difference, specifically includes:

[0014] The real-time measured height difference between the two suspensions located on the same side of the front axle suspension and the rear axle suspension in the first direction is obtained respectively;

[0015] Based on the two measured height differences and the initial height value, two boundary height values ​​corresponding to the left rear axle suspension and the right rear axle suspension are calculated respectively.

[0016] According to the technical solution provided in the embodiments of this application, the step of controlling the air spring system to operate when the boundary height value exceeds a preset height difference threshold specifically includes:

[0017] When any of the boundary height values ​​exceeds the preset height difference threshold, the real-time front axle height value of the front axle suspension on the same side as the rear axle suspension corresponding to the boundary height value is obtained.

[0018] The target leveling height value is calculated based on the front axle height value and the initial height difference.

[0019] Based on the target leveling height value, the operation of the air spring at the rear axle suspension corresponding to the boundary height value is controlled.

[0020] According to the technical solution provided in the embodiments of this application, the step of controlling the air spring system to operate when the boundary height value exceeds a preset height difference threshold specifically includes:

[0021] If both of the boundary height values ​​exceed the preset height difference threshold, then the real-time front axle height values ​​of the two side suspensions in the front axle suspension are obtained.

[0022] Based on the real-time front axle height values ​​corresponding to the two side suspensions and the initial height difference, the leveling height values ​​of the left rear axle suspension and the right rear axle suspension are calculated respectively.

[0023] Based on the leveling height values ​​of the left and right rear axle suspensions, the operation of the two air springs at the left and right rear axle suspensions is controlled respectively.

[0024] According to the technical solution provided in the embodiments of this application, before controlling the operation of the air spring at the rear axle suspension corresponding to the boundary height value, or before controlling the operation of the two air springs at the left rear axle suspension and the right rear axle suspension respectively, the method further includes:

[0025] Obtain the current speed and acceleration of the target vehicle;

[0026] If the vehicle speed is greater than a first preset vehicle speed threshold and the acceleration is less than a first preset acceleration threshold, then a designated air spring is controlled to operate. The designated air spring is the air spring at the rear axle suspension corresponding to any of the boundary height values ​​when the boundary height value exceeds the preset height difference threshold, or it is two air springs at the left rear axle suspension and the right rear axle suspension.

[0027] According to the technical solution provided in the embodiments of this application, the air spring system further includes a control circuit for controlling the two air springs; the control circuit includes at least: an air tank, an air tank control valve, at least two air spring control valves, and an exhaust valve;

[0028] The control of the specified air spring operation specifically includes:

[0029] A control command is sent to the air tank control valve, the air spring control valve corresponding to the designated air spring, and the exhaust valve to control the air tank to inflate the designated air spring or to exhaust air from the designated air spring through the exhaust valve; the control command includes at least: open or close.

[0030] The system acquires the real-time rear axle height value of one of the rear axle suspensions corresponding to the specified air spring, or the two suspensions of the left rear axle suspension and the right rear axle suspension. When the rear axle height value reaches the corresponding leveling height value, the system controls the air tank to stop supplying air to the specified air spring or to stop venting air from the specified air spring.

[0031] According to the technical solution provided in the embodiments of this application, the control loop further includes a compressor;

[0032] The method further includes:

[0033] Obtain the gas content inside the gas storage tank;

[0034] If the gas content is lower than a preset gas volume threshold, the compressor is controlled to charge the gas storage tank.

[0035] According to the technical solution provided in the embodiments of this application, after the rear axle height value reaches the corresponding leveling height value, the method further includes:

[0036] The adjustment time for one of the rear axle suspensions corresponding to the specified air spring, or for both the left and right rear axle suspensions, to reach the corresponding leveling height value, and the real-time pressure signal within the specified air spring are obtained.

[0037] If the adjustment time exceeds a preset time threshold and the pressure signal is detected abnormally, the air spring system is confirmed to be faulty, a fault alarm signal is sent, and the air spring system is disabled.

[0038] Secondly, this application provides a vehicle height control device based on a rear air suspension, comprising:

[0039] An initial height acquisition module is included, wherein the height detection module is used to acquire the initial height difference between the front axle suspension and the rear axle suspension in a first direction when a door opening signal of the target vehicle is received; an air spring system is provided at the rear axle suspension, wherein the air spring system is used to support and adjust the height of the rear axle suspension;

[0040] The height processing module, wherein the height detection module is used to obtain the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction when a door closing signal of the target vehicle is received, and to calculate the boundary height value based on the measured height difference and the initial height difference;

[0041] The judgment module is used to control the operation of the air spring system if the boundary height value exceeds a preset height difference threshold, thereby adjusting the current height of the rear axle suspension to achieve vehicle height control of the target vehicle.

[0042] In summary, this technical solution specifically discloses a vehicle height control method and device based on a rear air suspension. The vehicle height control method includes: upon receiving a door opening signal from a target vehicle, acquiring the initial height difference between the front axle suspension and the rear axle suspension in a first direction; an air spring system is installed at the rear axle suspension to support and adjust the height of the rear axle suspension; upon receiving a door closing signal from the target vehicle, acquiring the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction, and calculating a boundary height value based on the measured height difference and the initial height difference; if the boundary height value exceeds a preset height difference threshold, controlling the air spring system to operate, thereby adjusting the current height of the rear axle suspension to achieve vehicle height control of the target vehicle.

[0043] Existing air spring-based vehicle height adjustment systems mostly utilize four air springs to control vehicle height. However, in reality, some vehicles cannot use air suspension in the front suspension due to certain circumstances. This application provides a vehicle height control method for vehicles using air suspension only in the rear suspension. This method uses door opening and closing signals as preliminary conditions for vehicle height adjustment. It then calculates and determines whether the target vehicle needs vehicle height adjustment based on real-time measured height difference and initial height difference. If vehicle height adjustment is determined to be necessary, the air spring system at the rear axle suspension is controlled to operate. This method ensures the stability of the vehicle's posture in real time and effectively. Attached Figure Description

[0044] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0045] Figure 1 This is a flowchart illustrating a vehicle height control method based on a rear air suspension.

[0046] Figure 2 This is a flowchart illustrating step S100 in a vehicle height control method based on rear air suspension.

[0047] Figure 3 This is a flowchart illustrating step S200 in a vehicle height control method based on a rear air suspension.

[0048] Figure 4 This is a schematic diagram of the suspension system structure of the target vehicle.

[0049] Figure 5 This is a schematic diagram showing the initial height difference between the front and rear axle suspensions of the target vehicle in its initial posture.

[0050] Figure 6This is a schematic diagram showing the measured height difference between the front and rear axle suspensions of the target vehicle in the passenger boarding / alighting posture.

[0051] Figure 7 This is a schematic diagram comparing the height difference between the front and rear axle suspensions of the target vehicle in its initial and passenger boarding / alighting positions.

[0052] Figure 8 This is a schematic diagram of a vehicle height control device based on a rear air suspension.

[0053] The following are the labeling elements in the diagram: 101, Front Left Height Sensor; 102, Front Right Height Sensor; 103, Rear Left Height Sensor; 104, Rear Right Height Sensor; 201, ECU; 202, Compressor; 203, Solenoid Valve Assembly; 204, Air Tank; 300, Wheel; 401, Rear Axle Left Air Spring; 402, Rear Axle Right Air Spring; 600, Vehicle Height Control Device; 601, Initial Height Acquisition Module; 602, Height Processing Module; 603, Judgment Module; 604, Leveling Height Value Calculation Module; 605, Vehicle Parameter Acquisition Module; 606, Air Spring System Control Module. Detailed Implementation

[0054] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0055] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0056] Example 1

[0057] First, combined Figure 4 As can be seen, this method includes a target vehicle, which can be a new energy vehicle, such as a hybrid vehicle or a pure electric vehicle. The target vehicle includes a front axle suspension and a rear axle suspension. Since the space at the front of the vehicle is relatively limited, an air spring system is installed in the rear axle suspension to form a rear air suspension, which is used to adjust the vehicle height and stabilize the vehicle posture.

[0058] The following explains the suspension structure and other related aspects mentioned above.

[0059] The suspension system is mainly the mechanism that elastically connects the frame and the wheel 300. Its main function is to transmit all forces and torques acting between the wheel 300 and the frame, while mitigating the impact loads transmitted to the frame from uneven road surfaces. The air suspension system, on the other hand, uses airbags to support the vehicle body and adjusts the height and stiffness of the vehicle body by regulating the air pressure inside the airbags.

[0060] The air spring system is used to support the suspension and can adjust the height of the suspension according to road conditions and vehicle speed. The air spring system includes air springs corresponding to the left rear axle suspension and the right rear axle suspension respectively, as well as a control circuit that controls the operation of the air springs.

[0061] The control circuit includes at least: ① Compressor 202: The compressor 202 is used to pressurize atmospheric air and supply air to the air tank 204 or the air springs (including the rear axle left air spring 401 and the rear axle right air spring 402); ② Solenoid valve group 203: The solenoid valve group has 4 channels, including 2 air spring control valves, 1 air tank control valve, and 1 exhaust valve; ③ Air tank 204: Stores compressed air and inflates the air springs; ④ Height sensor: The height sensor is used to read the real-time height value of the suspension and send a corresponding height signal. In this embodiment, there are four height sensors, namely the left front height sensor 101, the right front height sensor 102, the left rear height sensor 103, and the right rear height sensor 104.

[0062] Combination Figure 4 As can be seen, this method can be executed by the vehicle itself, or by the vehicle's electronic control unit (ECU) and multiple sensors working together. For ease of explanation, the following description focuses on the ECU as the air suspension controller; please refer to [link / reference]. Figure 1 The flowchart shown in this embodiment illustrates a vehicle height control method based on a rear air suspension. The control method includes:

[0063] S100. When receiving the door opening signal collected by the vehicle detection sensor, the initial height difference between the front axle suspension and the rear axle suspension in the first direction is obtained; an air spring system is provided at the rear axle suspension, and the air spring system is used to support and adjust the height of the rear axle suspension.

[0064] The door opening signal is the signal that the door of the target vehicle is open. It can be collected by the corresponding sensors inside the vehicle. At the same time, the door opening signal is also the trigger condition for adjusting the height of the target vehicle.

[0065] When a door opening signal is received, the vehicle's height (posture) will be affected by the driver and passengers getting in and out of the vehicle, and the height of the front and rear axle suspensions will also change (see details). Figure 5 and Figure 6 Comparison of the height values ​​of the front axle suspension and the rear axle suspension.

[0066] The front axle suspension and rear axle suspension each include a left-side suspension and a right-side suspension; that is, the front axle suspension includes a left-side suspension located at the left front wheel and a right-side suspension located at the right front wheel; similarly, the rear axle suspension includes a left-side suspension located at the left rear wheel and a right-side suspension located at the right rear wheel. Furthermore, as can be seen from the foregoing, due to the relatively limited space at the front of the vehicle, the present invention only includes an air spring system in the rear axle suspension. This air spring system includes two air springs respectively located at the left and right rear axle suspensions to adjust the height of the two suspensions, thereby controlling the body adjustment of the target vehicle.

[0067] Since the height adjustment of the vehicle body mainly involves judging and adjusting the two suspensions on the same side of the target vehicle (specifically, the right suspension of the front axle and the right suspension of the rear axle are one set of judgment and control objects, while the left suspension of the front axle and the left suspension of the rear axle are another set of judgment and control objects), and the height control strategy for both sides is the same, for the sake of convenience, the height of the front axle suspension and the height of the rear axle suspension will be used as the basis for explanation.

[0068] like Figure 2 As shown, the adjustment of the vehicle body height needs to be based on the initial height difference of the target vehicle, so the initial height difference needs to be obtained in advance through the following steps;

[0069] S101. Obtain the vehicle information of the target vehicle; the vehicle information includes at least the initial attitude angle and the wheelbase of the front and rear wheels;

[0070] Vehicle information refers to the basic parameter information of the target vehicle, which can be calibrated by technicians at the beginning of the design. In order to calculate the initial height difference, it is necessary to obtain the initial attitude angle and the wheelbase of the front and rear wheels.

[0071] S102. The initial height difference is calculated based on the initial attitude angle and the wheelbase.

[0072] by Figure 5 Taking the situation shown as an example, the distance between the front axle suspension and the rear axle suspension can be expressed as the wheelbase, and the initial attitude angle... The initial height difference between the wheelbase and the wheel track can be calculated using basic trigonometric functions. .

[0073] For vehicle stability, the initial attitude angles of the front and rear axles of the target vehicle on both sides are kept consistent. Since the wheelbase of the front and rear wheels on both sides of the vehicle is also consistent, there is no distinction between the initial height difference on the left and right sides of the same target vehicle. However, different vehicles will have different initial attitude angles. The corresponding initial height difference will also be different. Similarly, different initial attitude angles can be defined for the left and right sides of the vehicle, without special restrictions here. Here, the first direction specifically refers to the vertical direction; and the initial attitude angle... It mainly refers to the horizontal angle formed by the line connecting the front axle suspension and the rear axle suspension on either side of the target vehicle.

[0074] S200: When a door closing signal of the target vehicle is received, the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction is obtained, and the boundary height value is calculated based on the measured height difference and the initial height difference.

[0075] The door closing signal is the door closing signal of the target vehicle. Once all doors of the target vehicle are closed, the measured height difference between the front and rear axle suspensions of the target vehicle is acquired, reflecting the situation after all passengers and drivers have boarded. Simultaneously, the horizontal angle formed by the lines connecting the front and rear axle suspensions on the same side of the target vehicle will also change after passengers have boarded, forming... Figure 6 The angle of boarding posture shown .

[0076] The boundary height value is used to determine whether the vehicle body needs to be adjusted in height.

[0077] The measured height difference is the height difference between the front and rear suspensions on the same side of the target vehicle's front axle suspension and rear axle suspension.

[0078] Furthermore, such as Figure 3 As shown, step S200 specifically includes:

[0079] S201. Obtain the real-time measured height difference in the first direction between the two suspensions located on the same side of the front axle suspension and the rear axle suspension;

[0080] The measured height difference can be calculated by collecting real-time height values ​​from the height sensors corresponding to the front and rear suspensions on the same side.

[0081] S202. Based on the two measured height differences and the initial height value, calculate the two boundary height values ​​corresponding to the left rear axle suspension and the right rear axle suspension, respectively.

[0082] Taking the left front axle suspension and left rear axle suspension of the target vehicle as an example, if the initial height difference is... The real-time measured height difference between the left front axle suspension and the left rear axle suspension is... The boundary height value It is calculated using the following formula (1):

[0083] Boundary height value (1)

[0084] The above formula (1) will calculate two boundary height values, and strictly speaking, the two boundary height values ​​correspond to the left front and rear axle suspension and the right front and rear axle suspension respectively.

[0085] S300. If the boundary height value exceeds the preset height difference threshold, the air spring system is controlled to operate, thereby adjusting the current height of the rear axle suspension to achieve vehicle height control of the target vehicle.

[0086] In practice, step S300 includes the following two adjustment scenarios:

[0087] Case 1: Any of the stated boundary height values Exceeding the preset height difference threshold;

[0088] Case 2: Both of the boundary height values ​​exceed the preset height difference threshold.

[0089] A preset height difference threshold can be selected, for example, as 4mm; however, in practice, the preset height difference threshold needs to be set according to the initial attitude angle of each vehicle model, and there is no specific limitation.

[0090] Specifically, for scenario one, step S300 includes:

[0091] Step 1: Any of the stated boundary height values When the height difference exceeds the preset height difference threshold, the real-time front axle height value of the front axle suspension on the same side as the rear axle suspension corresponding to the boundary height value is obtained;

[0092] When there is a boundary height value This means that the vehicle height needs to be adjusted at this point; therefore, considering the aforementioned placement of the air spring system, it is necessary to control the boundary height value that exceeds the preset height difference threshold. The corresponding air springs at the rear axle suspension operate to adjust the height of the rear axle suspension on the corresponding side, thereby stabilizing the vehicle's posture. It should be noted that whether to operate the air spring on the left or right side of the rear axle suspension depends on a boundary height value exceeding a preset height difference threshold. From the perspective of subordination.

[0093] Step 2: Calculate the target leveling height value based on the front axle height value and the initial height difference;

[0094] The target leveling height value is the boundary height value that exceeds the preset height difference threshold. The corresponding height value that the rear axle suspension needs to be adjusted to is based on ensuring that the real-time attitude angle formed by the front axle suspension and the rear axle suspension on the same side is consistent with the initial attitude angle. Therefore, it is necessary to ensure that the height difference between the front axle suspension and the rear axle suspension is consistent with the initial height difference.

[0095] like Figures 5-7 As shown, where, Figure 5 This is a schematic diagram showing the initial height difference between the front and rear axle suspensions on the same side of the target vehicle under their initial postures. Figure 6 This diagram illustrates the height difference between the front and rear axle suspensions on the same side of the target vehicle after passengers have boarded. It serves as a diagram for measuring the height difference. It is easy to see that the height values ​​of the front and rear axle suspensions are related to... Figure 5 Both have declined compared to the previous year; Figure 7 It can show the distance the current rear axle suspension needs to adjust to the desired height.

[0096] Furthermore, taking the left front axle suspension and rear axle suspension of the target vehicle as an example, the initial height difference is also... The real-time front axle height value is Target leveling height value It is calculated using the following formula (2):

[0097] Target leveling height value (2)

[0098] In addition, the target leveling height value can also be calculated by measuring the height difference and the initial height difference. In this case, the calculation formula is the same as formula (1).

[0099] Step 3: Based on the target leveling height value, control the operation of the air spring at the rear axle suspension corresponding to the boundary height value.

[0100] Once the target leveling height value is calculated, the corresponding air spring can be controlled to operate, so that the corresponding rear axle suspension (specifically the left rear axle suspension or the right rear axle suspension) reaches the target leveling height value and then stops. The specific control action can be to use the air spring to raise or lower the rear axle suspension.

[0101] In a preferred embodiment, since the passenger boarding situation of the target vehicle is varied in reality, there will inevitably be situations where the height of the target vehicle needs to be adjusted on both sides, the method also includes the above-mentioned second situation. For the second situation, step S300 specifically includes:

[0102] Step 1: If both of the boundary height values ​​exceed the preset height difference threshold, then obtain the real-time front axle height values ​​of the two side suspensions in the front axle suspension.

[0103] When both of the aforementioned boundary height values ​​exceed the preset height difference threshold, it indicates that both sides of the target vehicle need to be height adjusted. In this case, the calculation of the leveling height value is actually the same as the calculation principle of the aforementioned target adjustment height value. Therefore, it is necessary to first obtain the real-time front axle height values ​​of the suspensions on both sides of the current front axle suspension in order to perform subsequent calculations.

[0104] Step 2: Based on the real-time front axle height values ​​corresponding to the two side suspensions and the initial height difference, calculate the leveling height values ​​of the left rear axle suspension and the right rear axle suspension respectively.

[0105] The left rear axle suspension leveling height value is the height that the left rear axle suspension needs to be adjusted to when both rear axle suspensions need to be adjusted.

[0106] The rear axle right suspension leveling height value is the height that the rear axle right suspension needs to be adjusted to when both rear axle suspensions need to be adjusted.

[0107] In this step, the leveling height values ​​of the left and right rear axle suspensions are also calculated using the above formula (2). During the calculation process, only the real-time front axle height value needs to be considered. Simply substitute the real-time front axle height values ​​of the two sides of the front axle suspension obtained at the current location.

[0108] Step 3: Based on the leveling height values ​​of the left rear axle suspension and the right rear axle suspension, control the operation of the two air springs at the left and right rear axle suspensions respectively.

[0109] After obtaining the two corresponding leveling height values, these can be used as guidance data to control the operation of the two corresponding air springs, thereby ensuring the stability of the vehicle body posture by adjusting the height of the rear suspension bracket.

[0110] Furthermore, in a preferred embodiment, before controlling the operation of the air spring at the rear axle suspension corresponding to the boundary height value, or before controlling the operation of the two air springs at the left rear axle suspension and the right rear axle suspension respectively, in order to ensure stable vehicle height adjustment, the following entry conditions for the height adjustment stage need to be set:

[0111] Condition 1: Obtain the speed and acceleration of the target vehicle.

[0112] Condition 2: If the vehicle speed is greater than a first preset vehicle speed threshold and the acceleration is less than a first preset acceleration threshold, then the designated air spring is controlled to operate; the designated air spring is the air spring at the rear axle suspension corresponding to any of the boundary height values ​​when the boundary height value exceeds the preset height difference threshold, or it is the two air springs at the left rear axle suspension and the right rear axle suspension.

[0113] The term "air spring" refers to either one air spring that needs to operate in the two aforementioned different situations (for situation one, this air spring is the air spring at the rear axle suspension corresponding to the boundary height value that exceeds the preset height difference threshold) or two air springs that both need to be adjusted (when both of the boundary height values ​​exceed the preset height difference threshold).

[0114] The first preset vehicle speed threshold can be selected as 25km / h. When the vehicle speed is greater than 25km / h, the noise generated by the compressor in the vehicle is small. The first preset acceleration threshold can be selected as 0.1g to prevent the target vehicle from adjusting its height when making a sharp turn.

[0115] Furthermore, based on the foregoing description of the front axle suspension, rear axle suspension, and air spring system, the steps for "controlling the operation of a specified air spring" specifically include the following:

[0116] Step 1: Send control commands to the air tank control valve, the air spring control valve corresponding to the designated air spring, and the exhaust valve to control the air tank to inflate the designated air spring or to exhaust air from the designated air spring through the exhaust valve; the control commands include at least: open or close;

[0117] In a specific scenario, after calculating the target leveling height value, the next step is to control the operation of the air spring at the rear axle suspension corresponding to the boundary height value. In this case, the designated air spring is either the left rear axle air spring 401 or the right rear axle air spring 402. Inflating or deflating this air spring is necessary to adjust the height of the rear axle suspension. The specific air spring selected depends on the boundary height value exceeding a preset height difference threshold. From the perspective of subordination, we will not elaborate further here.

[0118] After calculating the leveling height values ​​of the left and right rear axle suspensions, the steps to be performed are to control the operation of the two air springs at the left and right rear axle suspensions respectively. At this time, the designated air springs are the left rear axle air spring 401 and the right rear axle air spring 402. The two air springs need to be inflated or deflated according to the calculated leveling height values ​​to adjust the height of the rear axle suspension.

[0119] Furthermore, whether to deflate or inflate the air springs depends on the leveling height value and the real-time rear axle height value of the rear axle suspension. If the rear axle height value is lower than the leveling height value, the corresponding air spring needs to be inflated; otherwise, the air spring needs to be deflated.

[0120] Step 2: Obtain the real-time rear axle height value of one of the rear axle suspensions corresponding to the specified air spring, or the two suspensions of the left rear axle suspension and the right rear axle suspension. When the rear axle height value reaches the corresponding leveling height value, control the air tank to stop supplying air to the specified air spring or stop venting air from the specified air spring.

[0121] It is important to note that when determining whether the rear axle suspension requiring adjustment has reached the leveling height value, this is typically done using a height sensor (see [link]). Figure 4 As shown, the left front height sensor 101, right front height sensor 102, left rear height sensor 103, and right rear height sensor 104 provide real-time feedback of the corresponding height information to determine the height. However, different vehicles will be calibrated with different height control advance amounts because there is a certain time difference between the inflation of the air spring and the actual raising or lowering process of the suspension. It is necessary to allow time for the gas to reach the air spring. Therefore, it is necessary to calibrate the height control advance amount in advance to prevent the air spring from being overcharged.

[0122] In addition, there are application scenarios where air springs need to be vented during vehicle height adjustment. For example, when the driver and passengers get off the vehicle or when passengers get off midway, if the rear axle suspension needs to be lowered from its original height to a certain value, the ECU201 needs to control the corresponding air spring to vent, which requires controlling the opening of the control valve and exhaust valve of the corresponding air spring.

[0123] In a preferred embodiment, in order to ensure the normal operation of the air spring, the control circuit further includes a compressor; the method ensures that the gas content in the air tank 204 meets the usage requirements through the following steps;

[0124] Step 1: Obtain the gas content inside the gas storage tank 204;

[0125] The gas content can be collected by a gas sensor to reflect the real-time gas content in the gas storage tank 204.

[0126] Step 2: If the gas content is lower than the preset gas volume threshold, control the compressor to charge the gas storage tank 204 with gas;

[0127] The preset gas volume threshold is a boundary value used to determine whether the gas in the gas storage tank 204 needs to be filled. This preset gas volume threshold needs to be set according to the design parameters of the gas storage tank 204 and the air spring. There are no special limitations. For example, the preset gas volume threshold can be selected as 20%.

[0128] In a preferred embodiment, during the height adjustment process, in response to the problem of air spring failure, after the rear axle height value reaches the corresponding leveling height value, the method further includes the following judgment step:

[0129] Step 1: Obtain the adjustment time of one of the rear axle suspensions corresponding to the specified air spring, or the two suspensions of the left rear axle suspension and the right rear axle suspension, to reach the corresponding leveling height value, and the real-time pressure signal in the specified air spring;

[0130] The adjustment duration is obtained by a timer, and the real-time pressure signal is obtained by a pressure sensor.

[0131] The adjustment time specifically includes: the time it takes for one of the rear axle suspensions corresponding to the specified air spring to reach the target leveling height value, the time it takes for the left rear axle suspension to reach the leveling height value of the left rear axle suspension, and the time it takes for the right rear axle suspension to reach the leveling height value of the right rear axle suspension.

[0132] Step 2: If the adjustment time exceeds the preset time threshold and the pressure signal is detected abnormally, the air spring system is confirmed to be faulty, a fault alarm signal is sent, and the air spring system is disabled.

[0133] The preset time threshold is a time boundary value used to determine whether the specified air spring has failed; abnormal pressure signal detection can be understood as an abnormal situation such as excessive pressure value or display as 0; when the above two situations occur, it is confirmed that the air spring system has a fault, and a fault alarm signal needs to be sent to the in-vehicle screen or other display terminals, while the system is disabled.

[0134] Example 2

[0135] This embodiment provides a vehicle height control device based on a rear air suspension, which applies the vehicle height control method based on a rear air suspension described in Embodiment 1, such as... Figure 8 As shown, the vehicle height control device 600 includes:

[0136] An initial height acquisition module 601 is used to acquire the initial height difference between the front axle suspension and the rear axle suspension in a first direction when a door opening signal of the target vehicle is received; an air spring system is provided at the rear axle suspension, and the air spring system is used to support and adjust the height of the rear axle suspension.

[0137] The height processing module 602, the height detection module 602 is used to obtain the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction when a door closing signal of the target vehicle is received, and to calculate the boundary height value based on the measured height difference and the initial height difference;

[0138] The judgment module 603 is used to control the operation of the air spring system if the boundary height value exceeds the preset height difference threshold, thereby adjusting the current height of the rear axle suspension to achieve the vehicle height control of the target vehicle.

[0139] In this embodiment, the initial height acquisition module 601 receives the door opening signal collected by the vehicle detection sensor, which also marks the beginning of the target vehicle height adjustment state. It then needs to start detecting and adjusting the vehicle body posture, subsequently calling vehicle information and obtaining the corresponding initial height difference. The height processing module 602 needs to perform real-time detection of the vehicle body posture when a door closing signal is detected, and simultaneously calculate the measured height difference and boundary height value between the front and rear axle suspensions on the same side. The judgment module 603 then receives and determines whether vehicle height adjustment is necessary. If vehicle height adjustment is required, it controls the air spring system to operate, thereby achieving control of the target vehicle body height.

[0140] In addition, the vehicle height control device 600 also includes: a leveling height calculation module 604, used to calculate the required height adjustment value of the corresponding rear axle suspension when the front and rear axle suspensions on any one or both sides need to be adjusted; a vehicle parameter acquisition module 605, used to collect the vehicle speed and acceleration of the target vehicle and determine whether the target vehicle's current state meets the requirements for entering the height adjustment stage; and an air spring system control module 606, used to perform the corresponding air spring inflation and deflation operations according to the calculated leveling height value, and at the same time, to monitor the gas content in the air tank 204 and the air spring failure to ensure the normal operation of the air spring system.

[0141] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A vehicle height control method based on rear air suspension, characterized in that, include: When a door opening signal is received from the target vehicle, the initial height difference between the front axle suspension and the rear axle suspension in the first direction is obtained; An air spring system is provided at the rear axle suspension, and the air spring system is used to support and adjust the height of the rear axle suspension. When a door closing signal is received from the target vehicle, the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction is obtained, and the boundary height value is calculated based on the measured height difference and the initial height difference. If the boundary height value exceeds the preset height difference threshold, the air spring system is controlled to operate, thereby adjusting the current height of the rear axle suspension to achieve vehicle height control of the target vehicle, so that the real-time attitude angle formed by the front axle suspension and the rear axle suspension on the same side is consistent with the initial attitude angle.

2. The vehicle height control method based on rear air suspension according to claim 1, characterized in that, The acquisition of the initial height difference between the front axle suspension and the rear axle suspension in the first direction specifically includes: Obtain vehicle information of the target vehicle; the vehicle information includes at least the initial attitude angle and the wheelbase of the front and rear wheels; The initial height difference is calculated based on the initial attitude angle and the wheelbase.

3. The vehicle height control method based on rear air suspension according to claim 1, characterized in that, The front axle suspension and the rear axle suspension each include a left suspension and a right suspension, and the air spring system includes two air springs corresponding to the left rear axle suspension and the right rear axle suspension, respectively; The step of obtaining the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction, and calculating the boundary height value based on the measured height difference and the initial height difference, specifically includes: The real-time measured height difference between the two suspensions located on the same side of the front axle suspension and the rear axle suspension in the first direction is obtained respectively; Based on the two measured height differences and the initial height difference, two boundary height values ​​corresponding to the left rear axle suspension and the right rear axle suspension are calculated respectively.

4. The vehicle height control method based on rear air suspension according to claim 3, characterized in that, If the boundary height value exceeds a preset height difference threshold, the air spring system is controlled to operate, specifically including: When any of the boundary height values ​​exceeds the preset height difference threshold, the real-time front axle height value of the front axle suspension on the same side as the rear axle suspension corresponding to the boundary height value is obtained. The target leveling height value is calculated based on the front axle height value and the initial height difference. Based on the target leveling height value, the operation of the air spring at the rear axle suspension corresponding to the boundary height value is controlled.

5. The vehicle height control method based on rear air suspension according to claim 3, characterized in that, If the boundary height value exceeds a preset height difference threshold, the air spring system is controlled to operate, specifically including: If both of the boundary height values ​​exceed the preset height difference threshold, then the real-time front axle height values ​​of the two side suspensions in the front axle suspension are obtained. Based on the real-time front axle height values ​​corresponding to the two side suspensions and the initial height difference, the leveling height values ​​of the left rear axle suspension and the right rear axle suspension are calculated respectively. Based on the leveling height values ​​of the left and right rear axle suspensions, the operation of the two air springs at the left and right rear axle suspensions is controlled respectively.

6. The vehicle height control method based on rear air suspension according to claim 4, characterized in that, Before the control of the air spring at the rear axle suspension corresponding to the boundary height value is activated, the method further includes: Obtain the current speed and acceleration of the target vehicle; If the vehicle speed is greater than a first preset vehicle speed threshold and the acceleration is less than a first preset acceleration threshold, then a designated air spring is controlled to operate. The designated air spring is the air spring at the rear axle suspension corresponding to any of the boundary height values ​​that exceeds the preset height difference threshold.

7. The vehicle height control method based on rear air suspension according to claim 5, characterized in that, Before controlling the operation of the two air springs at the left and right rear axle suspensions respectively, the method further includes: Obtain the current speed and acceleration of the target vehicle; If the vehicle speed is greater than a first preset vehicle speed threshold and the acceleration is less than a first preset acceleration threshold, then the designated air springs are controlled to operate. The designated air springs are the two air springs at the left rear axle suspension and the right rear axle suspension when any of the boundary height values ​​exceeds the preset height difference threshold.

8. The vehicle height control method based on rear air suspension according to claim 6 or 7, characterized in that, The air spring system also includes a control circuit for controlling the two air springs; the control circuit includes at least: an air tank, an air tank control valve, at least two air spring control valves, and an exhaust valve; The control of the specified air spring operation specifically includes: A control command is sent to the air tank control valve, the air spring control valve corresponding to the designated air spring, and the exhaust valve to control the air tank to inflate the designated air spring or to exhaust air from the designated air spring through the exhaust valve; the control command includes at least: open or close. The system acquires the real-time rear axle height value of one of the rear axle suspensions corresponding to the specified air spring, or the two suspensions of the left rear axle suspension and the right rear axle suspension. When the rear axle height value reaches the corresponding leveling height value, the system controls the air tank to stop supplying air to the specified air spring or to stop venting air from the specified air spring.

9. The vehicle height control method based on rear air suspension according to claim 8, characterized in that, The control circuit also includes a compressor; The method further includes: Obtain the gas content inside the gas storage tank; If the gas content is lower than a preset gas volume threshold, the compressor is controlled to charge the gas storage tank.

10. The vehicle height control method based on rear air suspension according to claim 9, characterized in that, After the rear axle height value reaches the corresponding leveling height value, the process further includes: The adjustment time for one of the rear axle suspensions corresponding to the specified air spring, or for both the left and right rear axle suspensions, to reach the corresponding leveling height value, and the real-time pressure signal within the specified air spring are obtained. If the adjustment time exceeds a preset time threshold and the pressure signal is detected abnormally, the air spring system is confirmed to be faulty, a fault alarm signal is sent, and the air spring system is disabled.

11. A vehicle height control device based on a rear air suspension, characterized in that, include: An initial height acquisition module is used to acquire the initial height difference between the front axle suspension and the rear axle suspension in a first direction when a door opening signal of the target vehicle is received; an air spring system is provided at the rear axle suspension to support and adjust the height of the rear axle suspension. A height processing module is used to obtain the real-time measured height difference between the front axle suspension and the rear axle suspension in the first direction when a door closing signal of the target vehicle is received, and to calculate the boundary height value based on the measured height difference and the initial height difference. The judgment module is used to control the air spring system to operate when the boundary height value exceeds the preset height difference threshold, thereby adjusting the current height of the rear axle suspension to achieve vehicle height control of the target vehicle, so that the real-time attitude angle formed by the front axle suspension and the rear axle suspension on the same side is consistent with the initial attitude angle.

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