Self-leveling suspension control system and control method, and vehicle

Abstract

The present invention discloses a control system and control method of a self-leveling suspension, and a vehicle. The control system obtains the pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels to an uneven road, calculates the pressure change value of each oil cylinder, and compares it with the pressure adjustment range of the accumulator. If the pressure change value of the oil cylinder is within the pressure adjustment range of the accumulator, active vibration reduction adjustment is not performed through oil replenishment by the hydraulic system, and passive vibration reduction adjustment is achieved only through self-compensation by the oil and gas system of the accumulator; if it exceeds the pressure adjustment range of the accumulator, the controller controls the hydraulic system to intervene to replenish oil in the oil cylinder to achieve active vibration reduction adjustment. In addition, the hydraulic system actively replenishes oil when the vehicle just travels to an uneven road, realizing the early intervention of the hydraulic system, which can effectively reduce the shaking amplitude of the suspension during the process of traveling from a flat road to an uneven road, making the vehicle travel more smoothly.

Description

Technical Field

[0001] The present invention relates to the technical field of self-leveling suspension, and in particular to a control system and a control method of a self-leveling suspension. In addition, the present invention also particularly relates to a vehicle using the control system of the self-leveling suspension. Background Art

[0002] The oil-gas suspension is a widely used automobile suspension at present, which can improve the driving smoothness, passability and fuel economy of the automobile. The current oil-gas suspension system often adopts an independent oil-gas separation system with a hydraulic four-cylinder accumulator. Each suspension cylinder is equipped with a magnetostrictive displacement sensor. The displacement sensor detects the telescopic displacement of each suspension cylinder, and the pressure sensor detects the internal pressure of each suspension cylinder. The tilt sensor detects the tilt angle of the whole vehicle in the front and rear directions and the left and right directions on the horizontal plane. A solenoid valve is set on the pipeline connecting each suspension cylinder and the oil pump. When the tilt sensor detects that the tilt angle of the vehicle body is within a certain threshold range, the suspension cylinder performs self-compensation through the oil-gas system of the accumulator connected to it to achieve passive vibration reduction. At this time, the corresponding solenoid valve is closed; when the tilt sensor detects that the tilt angle of the vehicle body exceeds a certain threshold range, the suspension cylinder in the corresponding position performs passive vibration reduction adjustment through the accumulator, and the controller controls the corresponding solenoid valve to open, and the oil pump of the hydraulic system performs active vibration reduction adjustment by replenishing or releasing oil. Passive vibration reduction adjustment through the accumulator can eliminate most road bumps, and active vibration reduction adjustment through the intervention of the hydraulic system can keep the vehicle relatively level on a certain slope and in local potholes, ensuring the stability of driving operations.

[0003] However, due to the feedback time of the adjustment speed of the hydraulic system and the frequency of the electronic control calculation, the existing leveling control strategy of the oil cylinder plus accumulator will have lag, and the faster the vehicle travels, the worse the leveling accuracy will be. The vehicle will shake more during the leveling process, which has little effect on vehicles with slower travel speed requirements, but is not applicable to vehicles with higher travel speed requirements. For example, for photovoltaic panel cleaning vehicles, the travel speed directly affects the operating efficiency. Therefore, the faster the vehicle speed is, the better it is under the premise of ensuring normal operation. Summary of the invention

[0004] The present invention provides a control system and a control method for a self-leveling suspension and a vehicle, so as to solve the technical problems that the leveling control strategy of the existing oil-gas suspension system has hysteresis and the vehicle has a large shaking amplitude.

[0005] According to one aspect of the present invention, a control system of a self-leveling suspension is provided, wherein the self-leveling suspension comprises four legs, each leg is provided with a cylinder and an accumulator connected thereto, each cylinder is provided with a pressure detection device, and a solenoid valve is provided on a pipeline connecting each cylinder and a hydraulic system, and the control system comprises:

[0006] The controller is electrically connected to the pressure detection device and the solenoid valve, and is used to obtain the pressure value of each cylinder when the vehicle is traveling on a flat road and the pressure value of each cylinder when the vehicle just travels to an uneven road, and calculate the pressure change value of each cylinder, and compare the pressure change value of each cylinder with the pressure adjustment range of the accumulator. If the pressure change value of the cylinder is within the pressure adjustment range of the accumulator, the solenoid valve corresponding to the cylinder is controlled to be closed; if the pressure change value of the cylinder exceeds the pressure adjustment range of the accumulator, the solenoid valve is controlled to be opened, and the hydraulic system is controlled to replenish oil to the cylinder.

[0007] Furthermore, the controller calculates the volume of oil replenished by the hydraulic system to each cylinder based on the following formula:

[0008] H n =k1*ΔP n -H0

[0009] Among them, H n It represents the oil replenishment volume of the hydraulic system to the nth cylinder, k1 represents the pressure adjustment coefficient, ΔP n It represents the pressure change value of the nth oil cylinder, and H0 represents the upper limit value of the oil adjustment volume of the accumulator.

[0010] Furthermore, the controller also calculates the oil replenishment flow rate of each cylinder according to the current vehicle speed and the oil replenishment volume.

[0011] Furthermore, each cylinder is equipped with a displacement sensor electrically connected to the controller for detecting the telescopic displacement of the cylinder. The controller is also used to calculate the height of each leg based on the detection results of the displacement sensor when the vehicle is traveling on an uneven road, and select the leg closest to the preset suspension height as the reference leg, and level the remaining three legs.

[0012] Furthermore, the suspension is also provided with an inclination detection device electrically connected to the controller, which is used to detect the inclination angle of the suspension in the front-to-back direction and the left-to-right direction. When the remaining three legs are leveled, the controller calculates the adjustment height of the three legs based on the following formula:

[0013] ΔZ2=X*tanα

[0014] ΔZ3=Y*tanβ

[0015] ΔZ4=X*tanα+Y*tanβ

[0016] Among them, ΔZ2 represents the adjusted height of the second leg, and the second leg is adjacent to the reference leg in the left-right direction, ΔZ3 represents the adjusted height of the third leg, and the third leg is adjacent to the reference leg in the front-back direction, ΔZ4 represents the adjusted height of the fourth leg, and the fourth leg is diagonally arranged with the reference leg, X represents the distance between the left and right legs when the suspension is in a horizontal state, Y represents the distance between the front and rear legs when the suspension is in a horizontal state, and α and β represent the inclination angles of the suspension in the left-right direction and the front-back direction, respectively.

[0017] Furthermore, the controller calculates the oil replenishment flow of each cylinder corresponding to the three legs that need to be leveled based on the following formula:

[0018] M2=k2*J2

[0019]

[0020]

[0021] Among them, M2, M3, and M4 represent the oil replenishment flow rates of the second leg, the third leg, and the fourth leg respectively, k2 represents the oil replenishment speed coefficient, and J2 represents the oil replenishment volume of the second leg during leveling, which is calculated based on the adjustment height and the cross-sectional area of ​​the cylinder.

[0022] Furthermore, the controller is also used to correct the pressure adjustment coefficient and the oil replenishment speed coefficient according to the operating data.

[0023] Furthermore, the controller divides an operating interval into N sub-intervals with a preset unit length, obtains the cylinder extension and contraction data with the largest adjustment stroke in each sub-interval, and calculates the average value of the N cylinder extension and contraction data. Then, the correction coefficient is set to iteratively correct the pressure adjustment coefficient and the oil replenishment speed coefficient, and the average value of the N cylinder extension and contraction data after each iterative correction is calculated until the average value is less than the preset threshold value, thereby obtaining the corrected pressure adjustment coefficient and the oil replenishment speed coefficient.

[0024] In addition, the present invention also provides a control method for a self-leveling suspension, wherein the self-leveling suspension includes four legs, each leg is provided with a cylinder and an accumulator connected thereto, each cylinder is provided with a pressure detection device, and a solenoid valve is provided on a pipeline connecting each cylinder and a hydraulic system, including the following contents:

[0025] The pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels on an uneven road are obtained respectively, and the pressure change value of each oil cylinder is calculated;

[0026] The pressure change value of each cylinder is compared with the pressure adjustment range of the accumulator. If the pressure change value of the cylinder is within the pressure adjustment range of the accumulator, the solenoid valve corresponding to the cylinder is controlled to close; if the pressure change value of the cylinder exceeds the pressure adjustment range of the accumulator, the solenoid valve is controlled to open and the hydraulic system is controlled to replenish oil to the cylinder.

[0027] In addition, the present invention also provides a vehicle, which adopts the control system as described above.

[0028] The present invention has the following effects:

[0029] The control system of the self-leveling suspension of the present invention obtains the pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels to an uneven road, thereby calculating the pressure change value of each oil cylinder when the vehicle enters an uneven road from a flat road, and comparing the pressure change value of each oil cylinder with the pressure adjustment range of the accumulator. If the pressure change value of the oil cylinder is within the pressure adjustment range of the accumulator, active vibration reduction adjustment is not performed by replenishing oil through the hydraulic system, and passive vibration reduction adjustment is achieved only through self-compensation of the oil and gas system of the accumulator; if the pressure change value of the oil cylinder exceeds the pressure adjustment range of the accumulator, it means that the adjustment stroke of the oil cylinder exceeds the adjustment range of the accumulator, and the controller controls the hydraulic system to intervene to replenish oil to the oil cylinder to achieve active vibration reduction adjustment. In addition, the controller controls the hydraulic system to actively replenish oil when the vehicle just travels to an uneven road, realizing the early intervention of the hydraulic system, which can effectively reduce the shaking amplitude of the suspension during the process of traveling from a flat road to an uneven road, making the vehicle travel more smoothly.

[0030] In addition, the control method and vehicle of the self-leveling suspension of the present invention also have the above advantages.

[0031] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 It is a schematic diagram of the module structure of the control system of the self-leveling suspension according to the preferred embodiment of the present invention.

[0034] Figure 2 It is a flow chart of a control method of a self-leveling suspension according to another embodiment of the present invention. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0036] It can be understood that a preferred embodiment of the present invention provides a control system for a self-leveling suspension, wherein the self-leveling suspension includes four legs, each leg is provided with a cylinder and an accumulator connected thereto, during initial calibration, the pre-charge pressure of the accumulator is about 8Mpa, each cylinder is in a neutral position, the total stroke of the cylinder is set to 405mm, the cylinder diameter is 120mm, and the rod diameter is 110mm. Each cylinder is provided with a pressure detection device, and a solenoid valve is provided on the pipeline connecting each cylinder to the hydraulic system. The pressure detection device is any one of a pressure sensor, a pressure transmitter and a pressure gauge, which is specifically arranged on the pipeline connecting the accumulator and the rodless chamber of the cylinder. Figure 1 As shown, the control system of the self-leveling suspension also includes a controller, which is electrically connected to the pressure detection device and the solenoid valve. The controller is used to obtain the pressure value of each cylinder when the vehicle is traveling on a flat road and the pressure value of each cylinder when the vehicle just travels to an uneven road, and calculate the pressure change value ΔP of each cylinder based on the pressure value before and after each cylinder travels. n , the pressure change value of each cylinder ΔP n Compare with the pressure adjustment range P0 of the accumulator. If the pressure change value of the cylinder is within the pressure adjustment range of the accumulator, that is, ΔP n ≤P0, the solenoid valve corresponding to the cylinder is controlled to close; if the pressure change value of the cylinder exceeds the pressure adjustment range of the accumulator, that is, ΔP n >P0, the solenoid valve is controlled to open, and the hydraulic system is controlled to replenish oil to the cylinder. When the cylinder needs to be extended, the hydraulic system replenishes oil to the rodless chamber of the cylinder, and when the cylinder needs to be retracted, the hydraulic system replenishes oil to the rod chamber of the cylinder.

[0037] It is understandable that when a vehicle travels from a flat road to an uneven road, it takes a certain amount of time for the mechanical structure of the suspension to tilt due to inertia, and the first thing to change is the pressure in the cylinder. If the pressure increases, it means that there is an uphill slope ahead, and if the pressure decreases, it means that there is a downhill slope ahead. The greater the pressure change, the greater the slope. In order to ensure that the upper plane of the suspension remains horizontal, the greater the stroke that the cylinder needs to adjust. The control system of the self-leveling suspension of this embodiment obtains the pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels to an uneven road, thereby calculating the pressure change value of each oil cylinder when the vehicle enters an uneven road from a flat road, and comparing the pressure change value of each oil cylinder with the pressure adjustment range of the accumulator. If the pressure change value of the oil cylinder is within the pressure adjustment range of the accumulator, active vibration reduction adjustment is not performed through oil replenishment by the hydraulic system, and passive vibration reduction adjustment is only achieved through self-compensation by the oil and gas system of the accumulator; if the pressure change value of the oil cylinder exceeds the pressure adjustment range of the accumulator, it means that the adjustment stroke of the oil cylinder exceeds the adjustment range of the accumulator, and the controller controls the hydraulic system to intervene to replenish oil to the oil cylinder to achieve active vibration reduction adjustment. In addition, the controller controls the hydraulic system to actively replenish oil when the vehicle just travels to an uneven road, realizing the early intervention of the hydraulic system, which can effectively reduce the shaking amplitude of the suspension during the process of traveling from a flat road to an uneven road, making the vehicle travel more smoothly.

[0038] Optionally, the controller calculates the volume of oil replenished by the hydraulic system to each cylinder based on the following formula:

[0039] H n =k1*ΔP n -H0

[0040] Among them, H n It indicates the oil replenishment volume of the hydraulic system for the nth cylinder, n = 1, 2, 3, 4, k1 indicates the pressure adjustment coefficient, ΔP n represents the pressure change value of the nth oil cylinder, and H0 represents the upper limit of the oil adjustment volume of the accumulator. It can be understood that the present invention can preliminarily estimate the volume of oil replenished by the hydraulic system to each oil cylinder based on the above formula, so as to estimate the adjustment stroke of each oil cylinder, thereby improving the leveling accuracy of the hydraulic system's early intervention.

[0041] Optionally, the controller also calculates the oil replenishment flow rate of each cylinder according to the current vehicle speed and the oil replenishment volume. Specifically, the controller calculates the oil replenishment flow rate of each cylinder based on the following formula:

[0042] L n =k2*H n *V

[0043] Among them, L nrepresents the oil replenishment flow of the nth cylinder, k2 represents the oil replenishment speed coefficient, and V represents the current vehicle speed.

[0044] It can be understood that if a fixed oil replenishment speed is used, there will be great differences in the leveling effect under different driving speeds and different oil replenishment volumes. The present invention calculates the oil replenishment flow of each cylinder based on the current vehicle speed and the oil replenishment volume, and accurately controls the oil replenishment speed, thereby further improving the leveling accuracy of the hydraulic system's early intervention.

[0045] It can be understood that each oil cylinder is equipped with a magnetostrictive displacement sensor for detecting the telescopic displacement of the oil cylinder. The inclination detection device can be any one of an inclination sensor, a total station, and an inclinometer. The controller is also used to calculate the height of each leg according to the detection result of the displacement sensor when the vehicle is traveling on an uneven road, and select the leg closest to the preset suspension height as the reference leg, and level the remaining three legs.

[0046] Specifically, when the hydraulic system intervenes in advance and the upper plane of the suspension is still not adjusted to a horizontal state when the vehicle is traveling on an uneven road, it is necessary to adjust the oil cylinder to restore the upper plane of the suspension to a horizontal state. The controller first obtains the telescopic displacement of the oil cylinder detected by each displacement sensor when the vehicle is traveling on an uneven road, and then calculates the height value of each leg at this time in combination with the initial height value of the leg. Then, the leg closest to the preset suspension height is selected as the reference leg, and the remaining three legs are leveled to restore the upper plane of the suspension to a horizontal state. Among them, the preset suspension height is the preset height value of each leg when the suspension is in a horizontal state.

[0047] It can be understood that the control system of the self-leveling suspension of the present invention, after the hydraulic system's early intervention still fails to adjust the suspension's upper plane to a horizontal state, calculates the height value of each leg and uses the leg closest to the preset suspension height as the reference leg to level the remaining three legs, thereby further correcting the suspension posture adjusted by the hydraulic system's early intervention, so that the suspension's upper plane returns to a horizontal state when the vehicle is traveling on an uneven road. By adopting the control strategy of early intervention and late correction, the leveling accuracy is greatly improved, and the shaking amplitude of the suspension during driving is further reduced, thereby improving driving stability.

[0048] It can be understood that the suspension is also provided with an inclination detection device electrically connected to the controller, which is used to detect the inclination angle of the suspension in the front-back direction and the left-right direction. When leveling the remaining three legs, the controller calculates the adjustment height of the three legs based on the following formula:

[0049] ΔZ2=X*tanα

[0050] ΔZ3=Y*tanβ

[0051] ΔZ4=X*tanα+Y*tanβ

[0052] Among them, ΔZ2 represents the adjustment height of the second leg, the second leg is adjacent to the reference leg in the left-right direction, ΔZ3 represents the adjustment height of the third leg, the third leg is adjacent to the reference leg in the front-back direction, ΔZ4 represents the adjustment height of the fourth leg, the fourth leg is set diagonally to the reference leg, X represents the distance between the left and right legs when the suspension is in a horizontal state, Y represents the distance between the front and back legs when the suspension is in a horizontal state, α and β represent the inclination angles of the suspension in the left-right direction and the front-back direction, respectively. It can be understood that the adjustment height of each leg is the telescopic distance of the corresponding cylinder, so the oil replenishment volume of each cylinder can be calculated based on the telescopic distance of each cylinder and the cylinder cross-sectional area.

[0053] It can be understood that the controller calculates the oil replenishment flow of each cylinder corresponding to the three legs that need to be leveled based on the following formula:

[0054] M2=k2*J2

[0055]

[0056]

[0057] Among them, M2, M3, and M4 represent the oil replenishment flow rates of the second leg, the third leg, and the fourth leg respectively, k2 represents the oil replenishment speed coefficient, and J2 represents the oil replenishment volume of the second leg during leveling, which is calculated based on the adjustment height and the cross-sectional area of ​​the cylinder.

[0058] It can be understood that the present invention controls the oil replenishment flow of the cylinders of each leveling leg by adopting the above-mentioned oil replenishment flow control scheme. Compared with each cylinder adjusting the corresponding leg to the target height at the fastest oil replenishment speed, the three adjusted legs form a plane that rotates as a whole relative to the reference leg, thereby achieving coordinated adjustment between the various adjustment legs, further reducing the shaking amplitude of the suspension during the leveling process, and thus further improving the driving stability.

[0059] It can be understood that, since the present invention adopts the control strategy of early intervention and late correction, and the early intervention leveling process and the late correction leveling process are performed synchronously in some time periods, therefore, for a certain synchronous moment, the oil replenishment amount of the cylinder is L n and M nWhen the wheel of a certain outrigger just passes the crest of the road, the mechanism tilts and the height of the outrigger needs to be lowered by contracting the oil cylinder. However, the road ahead is going downhill immediately, the oil cylinder pressure decreases and the oil cylinder needs to be extended again. At this time, the two oil replenishment amounts are neutralized and the amount of oil required by the hydraulic system is reduced, which is easy to control. At the same time, the suspension is more stable during the leveling process.

[0060] It can be understood that the values ​​of the pressure adjustment coefficient k1 and the oil replenishment speed coefficient k2 will directly affect the final value of the oil replenishment flow rate. If a fixed coefficient value is used, the accuracy is low, so it is necessary to frequently correct the pressure adjustment coefficient k1 and the oil replenishment speed coefficient k2 to ensure a better vibration reduction effect. Preferably, the controller is also used to correct the pressure adjustment coefficient and the oil replenishment speed coefficient according to the operating data. Specifically, the controller divides an operating interval into N sub-intervals with a preset unit length, obtains the cylinder extension data with the largest adjustment stroke in each sub-interval, and calculates the average value of N cylinder extension data, then sets the correction coefficient to iteratively correct the pressure adjustment coefficient and the oil replenishment speed coefficient, and calculates the average value of the N cylinder extension data after each iterative correction until the average value is less than the preset threshold value, and obtains the corrected pressure adjustment coefficient and oil replenishment speed coefficient.

[0061] For example, for a running distance of 1000m, it is divided into 10 sub-intervals with a unit length of 100m. For each sub-interval, the point with the largest inclination angle in this sub-interval is taken, and the cylinder extension data ΔZ with the largest adjustment stroke is obtained, and then the average value of the 10 sub-intervals is calculated. Then, a correction coefficient is set to iteratively correct the pressure adjustment coefficient and the oil filling speed coefficient. Specifically, in the first iteration, the pressure adjustment coefficient and the oil filling speed system are corrected to k1+k3 and k2+k3, and the new average value is calculated. like In the second iteration, the pressure adjustment coefficient and the oil filling speed system are corrected to k1-k3 and k2-k3; if In the second iteration, the pressure adjustment coefficient and the oil filling speed system are corrected to k1+2k3 and k2+2k3; the new average value is calculated in the second iteration. like If it is greater than or equal to the preset threshold, the coefficients of the third iteration are corrected to k1+3k3 and k2+3k3. Assuming that after n iterations, If it is less than the preset threshold, the iteration ends, and the corrected pressure adjustment coefficient and oil replenishment speed coefficient are k1+nk3 and k2+nk3.

[0062] In addition, if Figure 2As shown, another embodiment of the present invention further provides a control method for a self-leveling suspension, wherein the self-leveling suspension includes four legs, each leg is provided with a cylinder and an accumulator connected thereto, each cylinder is provided with a pressure detection device, and a solenoid valve is provided on a pipeline connecting each cylinder and a hydraulic system, and preferably adopts the control system as described above. The control method specifically includes the following contents:

[0063] Step S1: respectively obtaining the pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels on an uneven road, and calculating the pressure change value of each oil cylinder;

[0064] Step S2: Compare the pressure change value of each cylinder with the pressure adjustment range of the accumulator. If the pressure change value of the cylinder is within the pressure adjustment range of the accumulator, the solenoid valve corresponding to the cylinder is controlled to be closed; if the pressure change value of the cylinder exceeds the pressure adjustment range of the accumulator, the solenoid valve is controlled to open, and the hydraulic system is controlled to replenish oil to the cylinder.

[0065] It can be understood that the control method of the self-leveling suspension of this embodiment obtains the pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels to an uneven road, thereby calculating the pressure change value of each oil cylinder when the vehicle enters an uneven road from a flat road, and comparing the pressure change value of each oil cylinder with the pressure adjustment range of the accumulator. If the pressure change value of the oil cylinder is within the pressure adjustment range of the accumulator, active vibration reduction adjustment is not performed through oil replenishment by the hydraulic system, and passive vibration reduction adjustment is only achieved through self-compensation by the oil and gas system of the accumulator; if the pressure change value of the oil cylinder exceeds the pressure adjustment range of the accumulator, it means that the adjustment stroke of the oil cylinder exceeds the adjustment range of the accumulator, and the controller controls the hydraulic system to intervene to replenish oil to the oil cylinder to achieve active vibration reduction adjustment. In addition, the controller controls the hydraulic system to actively replenish oil when the vehicle just travels to an uneven road, realizing the early intervention of the hydraulic system, which can effectively reduce the shaking amplitude of the suspension during the process of traveling from a flat road to an uneven road, making the vehicle travel more smoothly.

[0066] In addition, another embodiment of the present invention further provides a vehicle, preferably using the control system as described above, wherein the vehicle is preferably a photovoltaic panel cleaning vehicle.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control system for a self-leveling suspension, wherein: The self-leveling suspension includes four legs, each leg is provided with a cylinder and an accumulator connected thereto, each cylinder is provided with a pressure detection device, and a solenoid valve is provided on the pipeline connecting each cylinder and the hydraulic system, and is characterized in that the control system includes: The controller is electrically connected to the pressure detection device and the solenoid valve, and is used to obtain the pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels to an uneven road, and calculate the pressure change value of each oil cylinder, and compare the pressure change value of each oil cylinder with the pressure adjustment range of the accumulator. If the pressure change value of the oil cylinder is within the pressure adjustment range of the accumulator, the solenoid valve corresponding to the oil cylinder is controlled to be closed; if the pressure change value of the oil cylinder exceeds the pressure adjustment range of the accumulator, the solenoid valve is controlled to be opened, and the hydraulic system is controlled to replenish oil to the oil cylinder; The controller calculates the volume of oil replenished by the hydraulic system to each cylinder based on the following formula: H n =k1*ΔP n -H0 Among them, H n It represents the oil replenishment volume of the hydraulic system to the nth cylinder, k1 represents the pressure adjustment coefficient, ΔP n It represents the pressure change value of the nth oil cylinder, and H0 represents the upper limit value of the oil adjustment volume of the accumulator.

2. The control system of the self-leveling suspension according to claim 1, characterized in that: The controller also calculates the oil replenishment flow of each cylinder based on the current vehicle speed and the oil replenishment volume.

3. The control system of the self-leveling suspension according to claim 1, characterized in that: Each cylinder is equipped with a displacement sensor electrically connected to the controller for detecting the telescopic displacement of the cylinder. The controller is also used to calculate the height of each leg based on the detection results of the displacement sensor when the vehicle is traveling on an uneven road, and select the leg closest to the preset suspension height as the reference leg to level the remaining three legs.

4. The control system of the self-leveling suspension according to claim 3, characterized in that: The suspension is also provided with an inclination detection device electrically connected to the controller, which is used to detect the inclination angle of the suspension in the front-to-back direction and the left-to-right direction. When the remaining three legs are leveled, the controller calculates the adjustment height of the three legs based on the following formula: ΔZ2=X*tanα ΔZ3=Y*tanβ ΔZ4=X*tanα+Y*tanβ Among them, ΔZ2 represents the adjusted height of the second leg, and the second leg is adjacent to the reference leg in the left-right direction, ΔZ3 represents the adjusted height of the third leg, and the third leg is adjacent to the reference leg in the front-back direction, ΔZ4 represents the adjusted height of the fourth leg, and the fourth leg is diagonally arranged with the reference leg, X represents the distance between the left and right legs when the suspension is in a horizontal state, Y represents the distance between the front and rear legs when the suspension is in a horizontal state, and α and β represent the inclination angles of the suspension in the left-right direction and the front-back direction, respectively.

5. The control system of the self-leveling suspension according to claim 4, characterized in that: The controller calculates the oil replenishment flow of the cylinders corresponding to the three legs that need to be leveled based on the following formula: M2=k2*J2 Among them, M2, M3, and M4 represent the oil replenishment flow rates of the second leg, the third leg, and the fourth leg respectively, k2 represents the oil replenishment speed coefficient, and J2 represents the oil replenishment volume of the second leg during leveling, which is calculated based on the adjustment height and the cross-sectional area of ​​the cylinder.

6. The control system of the self-leveling suspension according to claim 5, characterized in that: The controller is also used to correct the pressure adjustment factor and the oil filling speed factor according to the operating data.

7. The control system of the self-leveling suspension according to claim 6, characterized in that: The controller divides an operating interval into N sub-intervals with a preset unit length, obtains the cylinder expansion and contraction data with the largest adjustment stroke in each sub-interval, and calculates the average value of the N cylinder expansion and contraction data. Then, the correction coefficient is set to iteratively correct the pressure adjustment coefficient and the oil replenishment speed coefficient, and the average value of the N cylinder expansion and contraction data after each iterative correction is calculated until the average value is less than the preset threshold value, thereby obtaining the corrected pressure adjustment coefficient and the oil replenishment speed coefficient.

8. A method for controlling a self-leveling suspension, wherein: The self-leveling suspension includes four legs, each leg is provided with a cylinder and an accumulator connected thereto, each cylinder is provided with a pressure detection device, and a solenoid valve is provided on the pipeline connecting each cylinder and the hydraulic system, and is characterized in that it includes the following contents: The pressure value of each oil cylinder when the vehicle is traveling on a flat road and the pressure value of each oil cylinder when the vehicle just travels on an uneven road are obtained respectively, and the pressure change value of each oil cylinder is calculated; The pressure change value of each oil cylinder is compared with the pressure adjustment range of the accumulator. If the pressure change value of the oil cylinder is within the pressure adjustment range of the accumulator, the solenoid valve corresponding to the oil cylinder is controlled to close; if the pressure change value of the oil cylinder exceeds the pressure adjustment range of the accumulator, the solenoid valve is controlled to open, and the hydraulic system is controlled to replenish oil to the oil cylinder; The volume of oil replenished by the hydraulic system to each cylinder is calculated based on the following formula: H n =k1*ΔP n -H0 Among them, H n It represents the oil replenishment volume of the hydraulic system to the nth cylinder, k1 represents the pressure adjustment coefficient, ΔP n It represents the pressure change value of the nth oil cylinder, and H0 represents the upper limit value of the oil adjustment volume of the accumulator.

9. A vehicle, characterized in that: A control system as described in any one of claims 1 to 7 is adopted.

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