A commercial vehicle frame height automatic adjusting system and adjusting control method

Abstract

The application belongs to the technical field of frame height adjustment, and specifically provides a commercial vehicle frame height automatic adjustment system and an adjustment control method. The method comprises the following steps: acquiring the current vehicle speed and brake frequency in a set time period; determining the current driving road condition of the vehicle according to the vehicle speed and the brake frequency, and correcting the received target height according to the driving road condition; calculating the height difference between the current height and the corrected target height, and outputting a frame height control adjustment strategy; outputting the corresponding duty cycle according to the frame height control adjustment strategy, adjusting the air volume of the air spring by controlling the on-off state of the electromagnetic valve, and adjusting the frame to the corrected target height. By monitoring the vehicle speed and brake frequency in a set time period in real time, the application can intelligently determine the current driving road condition of the vehicle and dynamically adjust the target height of the frame accordingly. The application ensures that the vehicle can maintain the required vehicle body posture under different road conditions, thereby improving the safety and stability of driving.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of frame height adjustment, in particular to a commercial vehicle frame height automatic adjustment system and an adjustment control method. BACKGROUND

[0002] Traditional suspensions are mainly composed of steel plate springs or coil springs, shock absorbers and guide mechanisms, and their stiffness and damping cannot be adjusted, which are passive suspensions. With the development of new materials, electronic control technology, and new requirements of relevant regulations, high-end users and market demands, the design and application of air suspension systems have gradually improved.

[0003] Air suspensions use air springs as elastic elements, and their superior stiffness characteristics have been recognized by the market. They play a crucial role in improving the comfort of vehicles and can effectively reduce damage to the road. The market share is also rising.

[0004] However, existing air suspensions are manually adjusted to cause horizontal height changes, such as loading or unloading at loading docks, or when commercial vehicles are on ships to rest the vehicle body on rubber bumpers. The actual situation of the road is not taken into account, and the frame height cannot be automatically adjusted for different vehicle speeds and road conditions. Therefore, there is an urgent need for a commercial vehicle frame height automatic adjustment control method to achieve rapid and accurate control of the frame height of commercial vehicle air suspensions. SUMMARY

[0005] To solve the problem that the frame height of the air suspension system cannot be automatically adjusted for different vehicle speeds and road conditions, the present application provides a commercial vehicle frame height automatic adjustment system and an adjustment control method.

[0006] In the first aspect, the present application provides a commercial vehicle frame height automatic adjustment system, which includes a vehicle height control unit and an air spring arranged on the frame. The vehicle height control unit is connected with a target height determination unit, a frame height monitoring unit and an electromagnetic valve.

[0007] The air spring is connected with the electromagnetic valve, and the electromagnetic valve is connected with an air source.

[0008] The target height determination unit determines the target height of the vehicle frame according to the vehicle model and transmits it to the vehicle height control unit.

[0009] The frame height monitoring unit obtains the current height of the frame and transmits it to the vehicle height control unit.

[0010] The whole vehicle height control unit obtains the current vehicle speed and the brake frequency in the set time period, determines the current driving road condition of the vehicle according to the vehicle speed and the brake frequency, corrects the received target height according to the driving road condition, calculates the height difference between the current height and the corrected target height, formulates the vehicle frame height control adjustment strategy, outputs the corresponding duty cycle according to the vehicle frame height control adjustment strategy, adjusts the air spring inflation amount by controlling the on-off state of the electromagnetic valve, and adjusts the vehicle frame to the corrected target height.

[0011] As a preferred technical scheme of the present application, the vehicle frame height monitoring unit comprises a first height sensor arranged on the left vehicle frame and a second height sensor arranged on the right vehicle frame, the first height sensor transmits the collected height of the left vehicle frame to the whole vehicle height control unit, and the second height sensor transmits the collected height of the right vehicle frame to the whole vehicle height control unit.

[0012] As a preferred technical scheme of the present application, the whole vehicle height control unit obtains the current vehicle speed and the cumulative brake frequency in the current set time period, i.e. the brake frequency, through the CAN bus;

[0013] If the obtained vehicle speed is greater than the set vehicle speed and the brake frequency is lower than the first set threshold, it is determined that the vehicle is driving on the first road condition, the target height correction value corresponding to the first road condition is obtained, and the received target height input by the target height determination unit is corrected; wherein the corrected target height is equal to the difference between the received target height and the target height correction value;

[0014] If the obtained vehicle speed is less than or equal to the set vehicle speed and the brake frequency is higher than the first set threshold, it is determined that the vehicle is driving on the second road condition, the target height correction value corresponding to the second road condition is obtained, and the received target height input by the target height determination unit is corrected; wherein the corrected target height is equal to the sum of the received target height and the target height correction value.

[0015] As a preferred technical scheme of the present application, the whole vehicle height control unit calculates the first height difference L1 and the second height difference L2 of the left vehicle frame according to the vehicle frame height hl1 collected by the first height sensor and the corrected target height h0 corresponding to the road condition; and calculates the first height difference R1 and the second height difference R2 of the right vehicle frame according to the vehicle frame height hr1 collected by the second height sensor and the corrected target height h0.

[0016] The vehicle frame height control adjustment strategy is determined by comparing the first height difference and the second height difference of the left vehicle frame and the first height difference and the second height difference of the right vehicle frame.

[0017] As a preferred technical scheme of the present application, the vehicle frame height control adjustment strategy is as follows:

[0018] If ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0))!= 0 and L1 + R1 > L2 + R2, the vehicle height control unit sends a signal to the solenoid valve. At this time, if L1 > L2, the vehicle height control unit controls the solenoid valve to open, and the air spring on the left frame deflates, reducing the height of the left frame of the vehicle. If R1 > R2, the vehicle height control unit sends a signal to the solenoid valve, the solenoid valve opens, and the air spring on the right frame deflates, reducing the height of the right frame of the vehicle.

[0019] If ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0))!= 0 and L1 + R1 < L2 + R2, the vehicle height control unit sends a signal to the solenoid valve. At this time, if L1 < L2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring, increasing the height of the left frame of the vehicle. If R1 < R2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring, increasing the height of the right frame of the vehicle.

[0020] If ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0)) == 0, there is no need to adjust the height of the vehicle frame. The vehicle height control unit sends a signal to the solenoid valve, the solenoid valve closes, and the height of the vehicle frame remains unchanged.

[0021] As a preference of the technical solution of the present invention, the first height difference L1 of the left frame = hl1 - h0 - e, and the second height difference L2 of the left frame = h0 - hl1 - e;

[0022] The first height difference R1 of the right frame = hr1 - h0 - e, and the second height difference R2 of the right frame = h0 - hr1 - e;

[0023] In the formula, e is the allowable error value.

[0024] As a preference of the technical solution of the present invention, the vehicle height control unit continuously controls the average flow rate through the solenoid valve by adjusting the duty cycle D, realizes the control of the gas flow rate of the air spring, and further realizes the adjustment of the frame height;

[0025] The flow rate through the solenoid valve within a set time ;

[0026] In the formula, Q is the average flow rate through the solenoid valve within the time, is the flow coefficient, is the maximum area of the maximum opening of the solenoid valve, is the pressure difference of the air pressure, is the density of the gas.

[0027] In a second aspect, the present application provides a commercial vehicle frame height automatic adjustment control method, comprising the following steps:

[0028] obtaining the current height of the vehicle frame and the preset target height;

[0029] obtaining the current vehicle speed and the brake frequency in a set time period;

[0030] determining the current driving road condition of the vehicle according to the vehicle speed and the brake frequency, and correcting the received target height according to the driving road condition;

[0031] calculating the height difference between the current height and the corrected target height, and outputting a frame height control adjustment strategy;

[0032] outputting the corresponding duty cycle according to the frame height control adjustment strategy, adjusting the air spring inflation amount by controlling the on-off state of the electromagnetic valve, and adjusting the frame to the corrected target height.

[0033] As a preferred embodiment of the present application, the step of determining the current driving road condition of the vehicle according to the vehicle speed and the brake frequency, and correcting the received target height according to the driving road condition comprises:

[0034] if the obtained vehicle speed is greater than the set vehicle speed and the brake frequency is lower than the first set threshold, it is determined that the vehicle is driving on the first road condition, the target height correction value corresponding to the first road condition is obtained, and the received target height determined by the target height determination unit is corrected; wherein the corrected target height is equal to the difference between the received target height and the target height correction value;

[0035] if the obtained vehicle speed is less than or equal to the set vehicle speed and the brake frequency is higher than the first set threshold, it is determined that the vehicle is driving on the second road condition, the target height correction value corresponding to the second road condition is obtained, and the received target height determined by the target height determination unit is corrected; wherein the corrected target height is equal to the sum of the received target height and the target height correction value.

[0036] As a preferred embodiment of the present application, the whole vehicle height control unit calculates the first height difference L1 and the second height difference L2 of the left frame according to the frame height hl1 collected by the first height sensor and the target height h0 corrected according to the road condition, and calculates the first height difference R1 and the second height difference R2 of the right frame according to the frame height hr1 collected by the second height sensor and the corrected target height h0.

[0037] The frame height control adjustment strategy is determined by comparing the first height difference and the second height difference of the left frame and the first height difference and the second height difference of the right frame.

[0038] As the preferred technical scheme of the present application, the step of calculating the height difference between the current height and the corrected target height and outputting the vehicle frame height control adjustment strategy comprises:

[0039] The first height difference L1 and the second height difference L2 of the left frame are calculated according to the frame height hl1 collected by the first height sensor and the target height h0 corrected according to the road condition, and the first height difference R1 and the second height difference R2 of the right frame are calculated according to the frame height hr1 collected by the second height sensor and the corrected target height h0.

[0040] If (L1>0) || (L2>0) || (R1>0) || (R2>0)!=0 and L1+R1>L2+R2, the vehicle height control unit sends a signal to the electromagnetic valve; at this time, if L1>L2, the vehicle height control unit controls the electromagnetic valve to open, the air spring of the left frame is deflated, and the height of the left frame of the whole vehicle is lowered; if R1>R2, the vehicle height control unit sends a signal to the electromagnetic valve, the electromagnetic valve is opened, the air spring of the right frame is deflated, and the height of the right frame of the whole vehicle is lowered.

[0041] If (L1>0) || (L2>0) || (R1>0) || (R2>0)!=0 and L1+R1<L2+R2, the vehicle height control unit sends a signal to the electromagnetic valve; at this time, if L1<L2, the vehicle height control unit controls the electromagnetic valve to open, the air spring is inflated by the air source, the height of the left frame of the whole vehicle is raised, if R1<R2, the vehicle height control unit controls the electromagnetic valve to open, the air spring is inflated by the air source, and the height of the right frame of the whole vehicle is raised.

[0042] If ((L1>0) || (L2>0) || (R1>0) || (R2>0))==0, the vehicle frame height does not need to be adjusted, the vehicle height control unit sends a signal to the electromagnetic valve, the electromagnetic valve is closed, and the vehicle frame height remains unchanged.

[0043] As the preferred technical scheme of the present application, the first height difference L1 of the left frame is hl1-h0-e, and the second height difference L2 of the left frame is h0-hl1-e.

[0044] The first height difference R1 of the right frame is hr1-h0-e, and the second height difference R2 of the right frame is h0-hr1-e.

[0045] In the formula, e is an allowable error value.

[0046] As the preferred technical scheme of the present application, the vehicle height control unit continuously controls the average flow through the electromagnetic valve by adjusting the duty cycle D, realizes the control of the air spring gas flow, and further realizes the adjustment of the frame height.

[0047] Flow rate through the solenoid valve within a set time period ;

[0048] In the formula, Q is the average flow rate through the solenoid valve within a time interval. For flow coefficient, This represents the maximum area of ​​the solenoid valve's largest opening. The pressure difference is the air pressure. Let be the density of the gas.

[0049] As can be seen from the above technical solutions, the present invention has the following advantages: For commercial vehicles equipped with air suspension, an error range is set, which can not only effectively adjust the overall vehicle frame height, but also automatically adjust the overall vehicle frame height according to different road conditions compared with traditional control methods, effectively avoiding the impact of unsuitable air suspension height, thereby increasing the vehicle's handling stability and improving its fuel economy.

[0050] By monitoring vehicle speed and braking frequency over a set time period in real time, this invention can intelligently determine the current road conditions and dynamically adjust the target height of the chassis accordingly. This dynamic adjustment ensures that the vehicle maintains the required body posture under different road conditions, thereby improving driving safety and stability. The air spring inflation is precisely adjusted according to the corrected target height, which can more effectively absorb and dampen road vibrations, providing passengers with a smoother and more comfortable ride whether the vehicle is traveling on a smooth highway or a bumpy road.

[0051] This invention uses a target height determination unit to preset a target height based on the vehicle model, enabling the system to be applied to different commercial vehicle models without requiring individual settings for each vehicle type, greatly enhancing the system's versatility and adaptability. By intelligently adjusting the chassis height, this invention can minimize unnecessary energy consumption during vehicle operation while ensuring driving safety. For example, appropriately lowering the chassis height on flat roads can lower the vehicle's center of gravity, reduce wind resistance, and thus achieve energy conservation and emission reduction. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a system block diagram of an embodiment of the present invention.

[0054] Figure 2is a schematic flow chart of the method of one embodiment of the present application.

[0055] In the figure, 1 - first height sensor, 2 - second height sensor, 3 - air spring, 4 - vehicle height control unit, 5 - target height determination unit, 6 - electromagnetic valve, 7 - left side frame, 8 - right side frame, 9 - air source. DETAILED DESCRIPTION

[0056] For different road conditions, the target height of the vehicle is determined according to the vehicle parameters, the absolute value of the difference between the target height and the actual height is calculated, and the frame height is adjusted according to the absolute value of the difference, thereby improving the vehicle ride comfort, fuel economy and vehicle passability. The present application provides a commercial vehicle frame height automatic adjustment system and adjustment control method. In order to enable personnel in the technical field to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0057] As shown in Figure 1 the embodiment of the present application provides a commercial vehicle frame height automatic adjustment system, which comprises a vehicle height control unit 4 and an air spring 3 arranged on the frame, the vehicle height control unit 4 is connected with a target height determination unit 5, a frame height monitoring unit and an electromagnetic valve 6;

[0058] The air spring 3 is connected with the electromagnetic valve 6, and the electromagnetic valve 6 is connected with an air source 9;

[0059] The target height determination unit 5 determines the target height of the vehicle frame according to the vehicle model and transmits it to the vehicle height control unit 4;

[0060] The frame height monitoring unit obtains the current height of the frame and transmits it to the vehicle height control unit;

[0061] The vehicle height control unit obtains the current vehicle speed and the brake frequency in a set time period, determines the current driving road condition of the vehicle according to the vehicle speed and the brake frequency, corrects the received target height according to the driving road condition, calculates the height difference between the current height and the corrected target height, and formulates a frame height control adjustment strategy, outputs the corresponding duty cycle according to the frame height control adjustment strategy, adjusts the air charge of the air spring by controlling the on-off state of the electromagnetic valve, and adjusts the frame to the corrected target height.

[0062] The specific adjustment logic is as follows:

[0063] The current vehicle speed information is obtained in real time through the vehicle speed sensor. The vehicle height control unit records and counts the activation frequency of the brake system within a set time period (such as the past 1 minute, 5 minutes, etc.). According to the collected vehicle speed and brake frequency, combined with the preset algorithm or rule base, it is determined whether the vehicle is currently in a suburban road condition, a highway road condition, or other special road conditions (such as mountain roads, slopes, etc.). The target height determination unit receives the preset target vehicle frame height value. According to the determined driving road condition, the received target height is adjusted appropriately. For example, on a bumpy mountain road, the vehicle frame height may need to be lowered to improve stability, while on a highway, the vehicle frame height may need to be raised to improve driving comfort. The actual height of the current vehicle frame is obtained through the height sensor and compared with the corrected target height to calculate the difference between the two. According to the size and direction of the height difference, as well as the possible vehicle dynamic response requirements, specific strategies for adjusting the vehicle frame height are developed, including the direction of adjustment (up or down); according to the developed vehicle frame height control adjustment strategy, the corresponding electromagnetic valve control signal duty cycle is calculated and output. The duty cycle determines the opening and closing time ratio of the electromagnetic valve, thereby controlling the inflation or deflation rate of the air spring. The calculated duty cycle signal is converted into the actual control signal of the electromagnetic valve, and the inflation amount of the air spring is adjusted through the on-off state of the electromagnetic valve. The change in vehicle frame height is continuously monitored, and the control signal of the electromagnetic valve is adjusted as needed until the vehicle frame height reaches the corrected target height. The final adjustment result of the vehicle frame height is fed back to the vehicle control system or other related modules for further monitoring and analysis. During vehicle driving, the vehicle height control unit should continuously monitor the change in vehicle frame height and make necessary fine adjustments according to actual conditions to ensure that the vehicle frame height remains in the best state.

[0064] In some embodiments, the vehicle frame height monitoring unit includes a first height sensor 1 arranged on the left vehicle frame 7 and a second height sensor 2 arranged on the right vehicle frame 8, the first height sensor 1 transmits the collected height of the left vehicle frame 7 to the vehicle height control unit 4, and the second height sensor 2 transmits the collected height of the right vehicle frame 8 to the vehicle height control unit 4.

[0065] It should be noted that the first height sensor and the second height sensor are used to obtain the current height signals of the left and right vehicle frames respectively, and the current height signals are filtered and transmitted to the vehicle height control unit.

[0066] In some embodiments, the vehicle height control unit obtains the current vehicle speed and the cumulative number of brake times within the current set time period, i.e. the brake frequency, through the CAN bus;

[0067] If the acquired vehicle speed is greater than the set vehicle speed, and the brake frequency is lower than the first set threshold, it is determined that the vehicle is running on the first road condition, the target height correction value corresponding to the first road condition is acquired, and the target height input by the target height determination unit is corrected; wherein the corrected target height is equal to the difference between the received target height and the target height correction value; here, the first road condition is a highway, national road and other road conditions, under which the target height of the vehicle frame should be appropriately reduced to reduce wind resistance and improve fuel economy.

[0068] If the acquired vehicle speed is less than or equal to the set vehicle speed, and the brake frequency is higher than the first set threshold, it is determined that the vehicle is running on the second road condition, the target height correction value corresponding to the second road condition is acquired, and the target height input by the target height determination unit is corrected; wherein the corrected target height is equal to the sum of the received target height and the target height correction value; the second road condition is a rural road, mountain road and other road conditions, under which the target height of the vehicle frame should be appropriately increased to improve the riding comfort of the vehicle.

[0069] In some embodiments, the vehicle height control unit calculates the first height difference L1 and the second height difference L2 of the left side frame according to the frame height hl1 collected by the first height sensor and the target height h0 corrected according to the road condition; calculates the first height difference R1 and the second height difference R2 of the right side frame according to the frame height hr1 collected by the second height sensor and the corrected target height h0;

[0070] The frame height control adjustment strategy is determined by comparing the first height difference and the second height difference of the left side frame and the first height difference and the second height difference of the right side frame. By controlling the on-off state of the electromagnetic valve related to the adjustment of the vehicle frame height, the left side frame 7 and the right side frame 8 are adjusted from their respective current heights to the target height.

[0071] Here, the frame height control adjustment strategy is as follows:

[0072] If (L1>0) || (L2>0) || (R1>0) || (R2>0)!=0 and L1+R1>L2+R2, the vehicle height control unit sends a signal to the electromagnetic valve; at this time, if L1>L2, the vehicle height control unit controls the electromagnetic valve to open, the air spring of the left side frame is deflated, and the height of the left side frame of the vehicle is lowered; if R1>R2, the vehicle height control unit sends a signal to the electromagnetic valve, the electromagnetic valve is opened, the air spring of the right side frame is deflated, and the height of the right side frame of the vehicle is lowered;

[0073] If ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0))!= 0 and L1 + R1 < L2 + R2, the vehicle height control unit sends a signal to the solenoid valve; at this time, if L1 < L2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring to increase the height of the left frame of the vehicle. If R1 < R2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring to increase the height of the right frame of the vehicle.

[0074] If ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0)) == 0, there is no need to adjust the height of the vehicle frame. The vehicle height control unit sends a signal to the solenoid valve, and the solenoid valve closes, keeping the height of the vehicle frame unchanged.

[0075] It should be noted that ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0)) == 0 holds when L1 <= 0, L2 <= 0, R1 <= 0, and R2 <= 0 are all established simultaneously.

[0076] The first height difference L1 of the left frame = hl1 - h0 - e, and the second height difference L2 of the left frame = h0 - hl1 - e;

[0077] The first height difference R1 of the right frame = hr1 - h0 - e, and the second height difference R2 of the right frame = h0 - hr1 - e;

[0078] In the formula, e is the allowable error value. In the embodiment of the present invention, the range of the allowable error value e is [-5, +5] mm.

[0079] In some embodiments, during the deflation process, the vehicle height control unit determines the adjustment mode according to the height difference and applies this series of control commands to the electromagnetic coil of the solenoid valve. Then, within a cycle time There is Time when the valve passage is open and there is a flow Q passing through, and there is Time when the valve is closed and no flow passes through. The ratio of the time To Is the pulse width modulation rate (also known as the duty cycle), denoted as D = / , Is the pulse width, Is the pulse period. Let Q be the average flow rate through the solenoid valve, Is the flow coefficient, Is the maximum area of the maximum opening of the high-speed switching valve, Is the pressure difference, D is the pulse width signal modulation rate, The average flow Q through the electromagnetic valve in a certain time can be used to express the output flow of the electromagnetic valve in this time:

[0080]

[0081] By adjusting the duty cycle D of the station, the average flow through the electromagnetic valve can be continuously controlled, realizing the quasi-continuous control of the flow. The electromagnetic valve is controlled to be opened, and then the gas in the air spring is discharged through the electromagnetic valve exhaust port. When the deflation process is over, the vehicle height control unit sends a control signal to the electromagnetic valve to make it close, and the gas in the air spring stops discharging.

[0082] During the inflation process, the vehicle height control unit sends a control signal to the electromagnetic valve to make it open, and then the inflation source inflates the air spring. When the inflation process is over, the vehicle height control unit sends a control signal to the electromagnetic valve to make it close, and the inflation source stops inflating the air spring.

[0083] The adjustment of the vehicle frame height in the embodiment of the application includes but is not limited to the same height of the left and right vehicle frames.

[0084] The vehicle height control unit continuously controls the average flow through the electromagnetic valve by adjusting the duty cycle D, realizes the control of the air spring gas flow, and further realizes the adjustment of the vehicle frame height.

[0085] The flow through the electromagnetic valve in a certain time ;

[0086] In the formula, Q is the average flow through the electromagnetic valve in a certain time, is the flow coefficient, is the maximum area of the maximum opening of the electromagnetic valve, is the pressure difference of the gas pressure, is the density of the gas, the gas pressure in the air spring needs to be measured by setting a pressure sensor. Under the condition that the current vehicle weight is known, the vehicle frame height is received in real time when the pressure changes, and the corresponding height change is obtained, and the corresponding relationship between the pressure change and the duty cycle is obtained, and the adjustment of the vehicle frame height is realized.

[0087] Ensure that the height sensor accurately reflects the actual height of the vehicle frame. This usually needs to be done when the vehicle is stationary and the load is stable. According to the vehicle design and manufacturer's recommendations, set a baseline pressure value and the corresponding duty cycle as a reference point for subsequent adjustment. Collect the height information of the vehicle frame in real time through the height sensor and transmit it to the vehicle height control unit. Based on the vehicle design and experimental data, establish a mapping relationship between pressure change, vehicle frame height change and solenoid valve duty cycle. This mapping relationship may be linear or nonlinear, depending on the specific characteristics and needs of the vehicle. According to the perceived height change (and possibly pressure change), combined with the mapping relationship, determine the solenoid valve duty cycle that needs to be adjusted; send the calculated target duty cycle signal to the solenoid valve controller to adjust the on-off state of the solenoid valve, thereby changing the inflation or deflation rate of the air spring. Continue to receive data from the height sensor in real time to monitor the actual change of the vehicle frame height. If the vehicle frame height does not reach the expected target, recalculate the duty cycle according to the new height data and adjust the solenoid valve again until the vehicle frame height stabilizes within the target range. In practical applications, machine learning or adaptive algorithms are introduced to continuously optimize the pressure-height-duty cycle mapping relationship based on historical data and real-time feedback, improving the accuracy and efficiency of the adjustment.

[0088] As Figure 2 shown, the embodiment of the present application also provides a commercial vehicle frame height automatic adjustment control method, comprising the following steps:

[0089] Step 1: Obtain the current height of the vehicle frame and the preset target height;

[0090] Step 2: Obtain the current vehicle speed and brake frequency in a set time period;

[0091] Step 3: Determine the current driving road condition of the vehicle according to the vehicle speed and the brake frequency, and correct the received target height according to the driving road condition;

[0092] Step 4: Calculate the height difference between the current height and the corrected target height, and output the vehicle frame height control adjustment strategy;

[0093] Step 5: Output the corresponding duty cycle according to the vehicle frame height control adjustment strategy, adjust the inflation amount of the air spring by controlling the on-off state of the solenoid valve, and adjust the vehicle frame to the corrected target height.

[0094] In some embodiments, the step of determining the current driving road condition of the vehicle according to the vehicle speed and the brake frequency, and correcting the received target height according to the driving road condition comprises:

[0095] If the acquired vehicle speed is greater than the set vehicle speed, and the brake frequency is lower than the first set threshold, it is determined that the vehicle is running on the first road condition, the target height correction value corresponding to the first road condition is acquired, and the target height input by the target height determination unit is corrected; wherein the corrected target height is equal to the difference between the received target height and the target height correction value;

[0096] If the acquired vehicle speed is less than or equal to the set vehicle speed, and the brake frequency is higher than the first set threshold, it is determined that the vehicle is running on the second road condition, the target height correction value corresponding to the second road condition is acquired, and the target height input by the target height determination unit is corrected; wherein the corrected target height is equal to the sum of the received target height and the target height correction value.

[0097] In some embodiments, the vehicle height control unit calculates the first height difference L1 and the second height difference L2 of the left side frame according to the frame height hl1 collected by the first height sensor and the corrected target height h0 corresponding to the road condition; calculates the first height difference R1 and the second height difference R2 of the right side frame according to the frame height hr1 collected by the second height sensor and the corrected target height h0.

[0098] The frame height control adjustment strategy is determined by comparing the first height difference and the second height difference of the left side frame and the first height difference and the second height difference of the right side frame.

[0099] In some embodiments, the step of calculating the height difference between the current height and the corrected target height and outputting the frame height control adjustment strategy includes:

[0100] The first height difference L1 and the second height difference L2 of the left side frame are calculated according to the frame height hl1 collected by the first height sensor and the corrected target height h0 corresponding to the road condition; the first height difference R1 and the second height difference R2 of the right side frame are calculated according to the frame height hr1 collected by the second height sensor and the corrected target height h0.

[0101] If (L1>0) || (L2>0) || (R1>0) || (R2>0)!=0 and L1+R1>L2+R2, the vehicle height control unit sends a signal to the electromagnetic valve; at this time, if L1>L2, the vehicle height control unit controls the electromagnetic valve to open, the air spring of the left side frame is deflated, and the height of the left side frame of the vehicle is lowered; if R1>R2, the vehicle height control unit sends a signal to the electromagnetic valve, the electromagnetic valve is opened, the air spring of the right side frame is deflated, and the height of the right side frame of the vehicle is lowered;

[0102] If (L1>0) || (L2>0) || (R1>0) || (R2>0)!=0 and L1+R1<L2+R2, the vehicle height control unit sends a signal to the electromagnetic valve; at this time, if L1<L2, the vehicle height control unit controls the electromagnetic valve to open, and the air source charges the air spring to make the left side of the vehicle frame height rise, if R1<R2, the vehicle height control unit controls the electromagnetic valve to open, and the air source charges the air spring to make the right side of the vehicle frame height rise.

[0103] If ((L1>0) || (L2>0) || (R1>0) || (R2>0)) == 0, the vehicle frame height does not need to be adjusted, the vehicle height control unit sends a signal to the electromagnetic valve, the electromagnetic valve is closed, and the vehicle frame height remains unchanged.

[0104] It should be noted that ((L1>0) || (L2>0) || (R1>0) || (R2>0)) == 0 is true when L1<= 0, L2<=0, R1<= 0 and R2<= 0 are true at the same time.

[0105] Here, the first height difference L1 of the left frame is hl1-h0-e, and the second height difference L2 of the left frame is h0-hl1-e.

[0106] The first height difference R1 of the right frame is hr1-h0-e, and the second height difference R2 of the right frame is h0-hr1-e.

[0107] In the formula, e is an allowable error value.

[0108] In some embodiments, the method provided by the present application is based on the method of the system described in the above embodiments, specifically as follows:

[0109] The vehicle height control unit receives the target height determined by the target height determination unit according to the vehicle model; and receives the current height of the frame obtained by the frame height monitoring unit;

[0110] The vehicle height control unit obtains the current vehicle speed and brake frequency in a set time period, and determines the current driving road condition of the vehicle according to the vehicle speed and the brake frequency; corrects the received target height according to the driving road condition, calculates the height difference between the current height and the corrected target height, and formulates a frame height control adjustment strategy, outputs the corresponding duty cycle according to the frame height control adjustment strategy, adjusts the air volume of the air spring by controlling the on-off state of the electromagnetic valve, and adjusts the frame to the corrected target height.

[0111] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0112] The embodiments of the present invention provide an automatic adjustment control method for the chassis height of commercial vehicles. This method belongs to the same inventive concept as the automatic adjustment system for the chassis height of commercial vehicles described in the above embodiments. For details not described in detail in the embodiments of the automatic adjustment control method for the chassis height of commercial vehicles, please refer to the embodiments of the automatic adjustment system for the chassis height of commercial vehicles described above.

[0113] Although the present invention has been described in detail with reference to the accompanying drawings and preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention.

Claims

1. An automatic chassis height adjustment system for commercial vehicles, characterized in that, It includes a vehicle height control unit and an air spring mounted on the chassis. The vehicle height control unit is connected to a target height determination unit, a chassis height monitoring unit, and a solenoid valve. The air spring is connected to the solenoid valve, and the solenoid valve is connected to an air source; The target height determination unit determines the target height of the vehicle frame according to the vehicle model and transmits it to the vehicle height control unit; The chassis height monitoring unit acquires the current height of the chassis and transmits it to the vehicle height control unit; The vehicle height control unit acquires the current vehicle speed and the braking frequency over a set time period, determines the current road conditions based on the vehicle speed and the braking frequency, corrects the received target height based on the road conditions, calculates the height difference between the current height and the corrected target height, formulates a frame height control adjustment strategy, outputs the corresponding duty cycle based on the frame height control adjustment strategy, and adjusts the air spring inflation amount by controlling the on / off state of the solenoid valve to adjust the frame to the corrected target height. If the acquired vehicle speed is greater than the set vehicle speed and the braking frequency is lower than the first set threshold, it is determined that the vehicle is traveling in the first road condition. The target height correction value corresponding to the first road condition is acquired, and the target height input by the received target height determination unit is corrected. The corrected target height is equal to the difference between the received target height and the target height correction value. If the obtained vehicle speed is less than or equal to the set vehicle speed and the braking frequency is higher than the first set threshold, it is determined that the vehicle is traveling in the second road condition. The target height correction value corresponding to the second road condition is obtained, and the target height input by the target height determination unit is corrected. The corrected target height is equal to the sum of the received target height and the target height correction value. The vehicle height control unit continuously controls the average flow rate through the solenoid valve by adjusting the duty cycle D, thereby controlling the air flow rate of the air spring and adjusting the vehicle frame height. Flow rate through the solenoid valve within a set time period ; In the formula, Q is the average flow rate through the solenoid valve within a time interval. For flow coefficient, This represents the maximum area of ​​the solenoid valve's largest opening. The pressure difference is the air pressure. Let be the density of the gas.

2. The automatic vehicle frame height adjustment system according to claim 1, characterized in that, The chassis height monitoring unit includes a first height sensor located on the left side of the chassis and a second height sensor located on the right side of the chassis. The first height sensor transmits the height of the left side of the chassis to the vehicle height control unit, and the second height sensor transmits the height of the right side of the chassis to the vehicle height control unit.

3. The automatic vehicle frame height adjustment system according to claim 2, characterized in that, The vehicle height control unit calculates the first height difference L1 and the second height difference L2 of the left side frame based on the frame height hl1 collected by the first height sensor and the target height h0 after road condition correction; and calculates the first height difference R1 and the second height difference R2 of the right side frame based on the frame height hr1 collected by the second height sensor and the corrected target height h0. The frame height control adjustment strategy is determined by comparing the first and second height differences of the left frame and the first and second height differences of the right frame.

4. The automatic vehicle frame height adjustment system according to claim 3, characterized in that, The chassis height control and adjustment strategies include: When ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0))!= 0 and L1 + R1 > L2 + R2, the vehicle height control unit sends a signal to the solenoid valve. At this time, if L1 > L2, the vehicle height control unit controls the solenoid valve to open, and the air spring on the left frame deflates, reducing the height of the left frame of the vehicle. If R1 > R2, the vehicle height control unit sends a signal to the solenoid valve, the solenoid valve opens, and the air spring on the right frame deflates, reducing the height of the right frame of the vehicle. When ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0))!= 0 and L1 + R1 < L2 + R2, the vehicle height control unit sends a signal to the solenoid valve. At this time, if L1 < L2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring, increasing the height of the left frame of the vehicle. If R1 < R2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring, increasing the height of the right frame of the vehicle. When ((L1 > 0) || (L2 > 0) || (R1 > 0) || (R2 > 0)) == 0, there is no need to adjust the height of the vehicle frame. The vehicle height control unit sends a signal to the solenoid valve, and the solenoid valve closes, keeping the height of the vehicle frame unchanged.

5. The automatic vehicle frame height adjustment system according to claim 4, characterized in that, The first height difference L1 of the left frame = hl1 - h0 - e, and the second height difference L2 of the left frame = h0 - hl1 - e; The first height difference R1 of the right frame = hr1 - h0 - e, and the second height difference R2 of the right frame = h0 - hr1 - e; In the formula, e is the allowable error value.

6. A method for automatic adjustment and control of the chassis height of a commercial vehicle applied to the system described in any one of claims 1-5, characterized in that, It includes the following steps: Obtain the current height of the vehicle frame and the preset target height; Obtain the current vehicle speed and the braking frequency within a set time period; Judge the current driving condition of the vehicle according to the vehicle speed and the braking frequency, and correct the received target height according to the driving condition; Calculate the height difference between the current height and the corrected target height, and output the vehicle frame height control adjustment strategy; Output the corresponding duty cycle according to the vehicle frame height control adjustment strategy, and adjust the inflation amount of the air spring by controlling the on-off state of the solenoid valve to adjust the vehicle frame to the corrected target height.

7. The automatic adjustment and control method for the frame height of a commercial vehicle according to claim 6, characterized in that, The step of judging the current driving condition of the vehicle according to the vehicle speed and the braking frequency, and correcting the received target height according to the driving condition includes: If the obtained vehicle speed is greater than the set vehicle speed and the braking frequency is lower than the first set threshold, it is determined that the vehicle is driving in the first driving condition, obtain the target height correction value corresponding to the first driving condition, and correct the target height input by the target height determination unit received; among them, the corrected target height is equal to the received target height minus the target height correction value; If the obtained vehicle speed is less than or equal to the set vehicle speed and the braking frequency is higher than the first set threshold, it is determined that the vehicle is driving in the second driving condition, obtain the target height correction value corresponding to the second driving condition, and correct the target height input by the target height determination unit received; among them, the corrected target height is equal to the received target height plus the target height correction value.

8. The automatic adjustment and control method for the frame height of a commercial vehicle according to claim 7, characterized in that, The steps of calculating the height difference between the current height and the corrected target height and outputting the vehicle frame height control adjustment strategy include: Calculating the first height difference L1 and the second height difference L2 of the left vehicle frame according to the vehicle frame height hl1 collected by the first height sensor and the corrected target height h0 corresponding to the road condition; calculating the first height difference R1 and the second height difference R2 of the right vehicle frame according to the vehicle frame height hr1 collected by the second height sensor and the corrected target height h0; If (L1 > |0|) || (L2 > |0|) || (R1 > |0|) || (R2 > |0|)!= 0 and L1 + R1 > L2 + R2, the vehicle height control unit sends a signal to the solenoid valve; at this time, if L1 > L2, the vehicle height control unit controls the solenoid valve to open, and the air spring of the left vehicle frame deflates, reducing the height of the left vehicle frame of the whole vehicle; if R1 > R2, the vehicle height control unit sends a signal to the solenoid valve, the solenoid valve opens, and the air spring of the right vehicle frame deflates, reducing the height of the right vehicle frame of the whole vehicle; If (L1 > |0|) || (L2 > |0|) || (R1 > |0|) || (R2 > |0|)!= 0 and L1 + R1 < L2 + R2, the vehicle height control unit sends a signal to the solenoid valve; at this time, if L1 < L2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring, increasing the height of the left vehicle frame of the whole vehicle; if R1 < R2, the vehicle height control unit controls the solenoid valve to open, and the inflation source inflates the air spring, increasing the height of the right vehicle frame of the whole vehicle; If ((L1 > |0|) || (L2 > |0|) || (R1 > |0|) || (R2 > |0|)) == 0, there is no need to adjust the vehicle frame height of the whole vehicle. The vehicle height control unit sends a signal to the solenoid valve, and the solenoid valve closes, keeping the vehicle frame height of the whole vehicle unchanged. Note: In the original Chinese text, the logical expressions seem a bit inconsistent in terms of the use of "!= 0" which might be a typo. In the translation, I added "|0|" to make the logical expressions more standard in English. If this is not what you intended, please clarify.

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