Intelligent hydraulic four-wheel interconnected active suspension system and control method, and vehicle

Abstract

The present application relates to the technical field of vehicle suspension system, in particular to an intelligent hydraulic four-wheel interconnected active suspension system, a control method and a vehicle. The intelligent hydraulic four-wheel interconnected active suspension system comprises multiple hydraulic branches, multiple wheel-end hydraulic cylinders which can be connected in parallel with coil springs, a set of control valves, multiple communication pipelines, multiple accumulators, multiple stiffness regulators and damping regulators, and an energy supply unit. The present application can not only realize vehicle body lifting, multiple stiffness modes, damping stepless adjustment, four-wheel leveling, slope driving posture adjustment, cross-axis and rough road driving adjustment, but also can adaptively suppress the roll, pitch and vertical heave of the vehicle body in each stiffness mode. The present application has simple structure and good driving condition adaptability, and makes the vehicle more suitable for multi-condition driving including off-road driving.

Description

Technical Field

[0001] This invention relates to the field of vehicle suspension system technology, specifically to an intelligent hydraulic four-wheel interconnected active suspension system and control method, and a vehicle. Background Technology

[0002] Currently, the four-wheel interconnected air suspension used in off-road vehicles typically uses a central balance cylinder interconnection method. Although this can improve grounding in off-road conditions, it lacks off-road camping leveling and hill-start assist functions. In non-off-road conditions, the vehicle rolls too much and requires a stabilizer bar. However, using a passive stabilizer bar would reduce the vehicle's off-road performance, while using an active stabilizer bar is too expensive.

[0003] Meanwhile, existing technologies used in commercial vehicles, engineering vehicles, buses, and some off-road vehicles for four-wheel interconnected hydropneumatic suspensions, although employing interconnection methods with upper and lower chambers of hydraulic cylinders, have limited stiffness adjustment and cannot be used for four-wheel leveling and decoupling adjustment of vehicle height before and after hill climbing, thus having off-road limitations. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an intelligent hydraulic four-wheel interconnected active suspension system and control method to address the shortcomings of the existing technology, which can effectively improve the off-road driving experience of vehicles.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] I. An intelligent hydraulic four-wheel interconnected active suspension system

[0007] This invention provides an intelligent hydraulic four-wheel interconnected active suspension system, including lifting hydraulic cylinders, stiffness adjusters, damping adjusters, control valve assemblies, and a power supply unit located at the four wheel ends of a vehicle. The upper and lower chambers of the four wheel-end hydraulic cylinders are interconnected through multiple hydraulic lines, and each wheel-end hydraulic cylinder has a stiffness adjuster and a damping adjuster on its hydraulic line. The control valve assemblies include a distribution valve assembly and multiple interconnected switching valves, which are located on the interconnected hydraulic lines of the four wheel-end hydraulic cylinders. The distribution valve assembly is connected to the power supply unit, which includes an oil pump assembly and an accumulator.

[0008] Preferably, the upper and lower chambers of the four wheel-end hydraulic cylinders are interconnected as follows: the upper chamber of the left front wheel-end hydraulic cylinder is connected to the lower chamber of the right front wheel-end hydraulic cylinder via pipe one; the lower chamber of the left front wheel-end hydraulic cylinder is connected to the upper chamber of the right front wheel-end hydraulic cylinder via pipe two; the upper chamber of the left rear wheel-end hydraulic cylinder is connected to the lower chamber of the right rear wheel-end hydraulic cylinder via pipe three; and the lower chamber of the left rear wheel-end hydraulic cylinder is connected to the upper chamber of the right rear wheel-end hydraulic cylinder via pipe four; and pipe two and pipe four are connected via pipe five, and pipe one and pipe three are connected via pipe six.

[0009] Preferably, the distribution valve assembly includes a left front oil circuit switch valve, a right front oil circuit switch valve, a left rear oil circuit switch valve, and a right rear oil circuit switch valve;

[0010] The left front oil circuit switch valve is connected to the first pipeline through oil pipe one, the right front oil circuit switch valve is connected to the second pipeline through oil pipe two, the left rear oil circuit switch valve is connected to the third pipeline through oil pipe three, and the right rear oil circuit switch valve is connected to the fourth pipeline through oil pipe four.

[0011] Furthermore, a front valve is provided between oil pipe one and oil pipe two, and a rear valve is provided between oil pipe three and oil pipe four.

[0012] Preferably, the first, second, third, and fourth pipelines are respectively equipped with a left-right interconnection switch valve for the right side of the front suspension, a left-right interconnection switch valve for the left side of the front suspension, a left-right interconnection switch valve for the right side of the rear suspension, and a left-right interconnection switch valve for the left side of the rear suspension.

[0013] Preferably, pipeline five and pipeline six are respectively equipped with a left-side front-to-back interconnected switch valve and a right-side front-to-back interconnected switch valve.

[0014] Preferably, each of the first, second, third, and fourth pipelines is equipped with two stiffness regulators and two damping regulators. The stiffness regulator contains an electromagnetic switch and an energy storage device, and the damping regulator contains an electromagnetic proportional valve.

[0015] Preferably, the upper chamber of the wheel-end hydraulic cylinder is a rodless chamber, and the lower chamber is a rod-type chamber; all four wheel-end hydraulic cylinders are connected in parallel with corresponding spring elements to jointly support the weight of the vehicle body.

[0016] Preferably, the lifting hydraulic cylinders, stiffness adjusters, damping adjusters, control valve groups, and power supply units at the four wheel ends are all electrically connected to the active suspension controller.

[0017] II. A Control Method for an Intelligent Hydraulic Four-Wheel Interconnected Active Suspension System

[0018] Based on the same inventive concept, the present invention also provides a control method for the intelligent hydraulic four-wheel interconnected active suspension system as described above, specifically including the following steps:

[0019] S1, Vehicle body lifting control: Open all solenoid valves in the distribution valve assembly, close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve, and then open the oil pump group in the power supply unit to raise the vehicle body to the preset height one.

[0020] S2, Vehicle body descent control: Open all solenoid valves in the distribution valve assembly, close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve, then close the oil pump group in the power supply unit, and at the same time mechanically open the oil return port of the oil pump group to lower the vehicle body to the preset height two.

[0021] S3, Stiffness Adjustment Control: Multi-level adjustment of the stiffness of each wheel end is achieved by opening and closing the first stiffness adjuster and the second stiffness adjuster on the hydraulic cylinder oil circuit of each wheel end respectively.

[0022] S4, Damping Adjustment Control: Based on the acceleration sensor signals of each wheel and the six-axis acceleration sensor signals of the vehicle body, the electromagnetic proportional valve of the damping adjuster on the hydraulic cylinder oil circuit of each wheel end is adjusted in real time to adjust the damping of each wheel end;

[0023] S5, Camping Leveling Control: Close all interconnection switch valves to cut off the vehicle's four-wheel interconnection. Based on the onboard level indicator signal, individually open the branch oil circuit switch valves of each wheel. In conjunction with the opening and closing of the power supply unit, adjust the suspension height of each wheel individually to level the vehicle body as a whole.

[0024] S6, Hill Climbing Driving Height Control: Close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve to disconnect the front and rear wheels of the vehicles. Open the left rear oil circuit switch valve, the right rear oil circuit switch valve and the rear door valve. At the same time, close the left front oil circuit switch valve, the right front oil circuit switch valve and the front door valve. Then, turn on the oil pump unit in the power supply unit to raise the rear axle of the vehicle to the preset height of three.

[0025] S7, Downhill driving height control: Close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve to disconnect the front and rear wheels of the vehicles. Open the left front oil circuit switch valve, the right front oil circuit switch valve and the front door valve. At the same time, close the left rear oil circuit switch valve, the right rear oil circuit switch valve and the rear door valve. Then, turn on the oil pump group in the power supply unit to raise the front axle of the vehicle to the preset height of four.

[0026] S8, Normal Driving Control: All solenoid valves, oil pump group, accumulator, and left and right front-to-rear interconnection switch valves in the distribution valve assembly are closed, which can adaptively suppress body roll, pitch and vertical bumps under each stiffness mode and damping adjustment.

[0027] S9, Cross-Axle and Rough Road Driving Control: All solenoid valves, oil pump group and accumulator in the distribution valve assembly are closed, and the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve are open. This generates almost no torsional torque on the vehicle body, reduces the chance of the tires leaving the ground and improves the vehicle's off-road performance.

[0028] Compared with the prior art, the present invention has the following main advantages:

[0029] 1. This invention proposes an intelligent hydraulic four-wheel interconnected active suspension system. By rationally arranging the interconnected hydraulic pipelines of the hydraulic cylinders at the four wheel ends of the vehicle, and in conjunction with stiffness adjusters, damping adjusters, control valve groups, and power supply units, it can not only realize vehicle body lifting, multiple stiffness modes, stepless damping adjustment, four-wheel leveling, slope driving posture adjustment, cross-axle and rough road driving adjustment, but also adaptively suppress the body roll, pitch and vertical bumps in each stiffness mode. Moreover, the overall structure is simple and easy to debug and maintain.

[0030] 2. This invention proposes a control method for an intelligent hydraulic four-wheel interconnected active suspension system. By combining information from various vehicle sensors to intelligently control the control valve group, the vehicle can adapt to various driving conditions, including off-road driving, thereby improving the vehicle's driving adaptability and driving comfort. Attached Figure Description

[0031] Figure 1 This is an overall schematic diagram of the intelligent hydraulic four-wheel interconnected active suspension system in an embodiment of the present invention;

[0032] Figure 2 This is a control block diagram of the active suspension system in an embodiment of the present invention;

[0033] Figure 3 This is a flowchart of the control method in an embodiment of the present invention.

[0034] In the diagram: 1-oil pump assembly; 2-accumulator; 3-distribution valve assembly; 3.1-left front oil circuit switch valve; 3.2-right front oil circuit switch valve; 3.3-front valve; 3.4-left rear oil circuit switch valve; 3.5-right rear oil circuit switch valve; 3.6-rear valve; 4-left front first stiffness adjuster; 5-left front second stiffness adjuster; 6-left front first damping adjuster; 7-left front depressurization chamber; 8-left front second damping adjuster; 9-left front-rear interconnection switch valve; 10-right side 11-Left forward (return) oil pipe; 12-Left front upper main oil pipe; 13-Left left side interconnection switch valve of front suspension; 14-Left right side interconnection switch valve of front suspension; 15-Left front wheel end hydraulic cylinder; 15.1-Left front spring element; 15.2-Left front hydraulic cylinder; 16-Right front wheel end hydraulic cylinder; 17-Left rear wheel end hydraulic cylinder; 18-Right rear wheel end hydraulic cylinder; 19-Left left side interconnection switch valve of rear suspension; 20-Left right side interconnection switch valve of rear suspension. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0036] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0037] Example 1: This example provides an intelligent hydraulic four-wheel interconnected active suspension system, including the upper and lower chambers of four interconnected wheel-end hydraulic cylinders, a set of control valve groups, several connecting pipelines, several accumulators, several stiffness adjusters and damping adjusters, and a power supply unit.

[0038] The four hydraulic cylinders are connected in parallel with the coil springs to support the weight of the vehicle body. Each wheel end main oil circuit is equipped with two stiffness adjusters, one pressure reducing air chamber and two damping controllers. The damping controller is a damping adjuster dominated by an electromagnetic proportional valve, which can realize stepless adjustment of damping.

[0039] Furthermore, the upper and lower chambers of the four wheel-end hydraulic cylinders are interconnected by multiple hydraulic lines. Four of these lines are connected to the rod-side working chamber of the hydraulic cylinder through the inner hole of the piston rod. At the same time, six switching valves are installed on the interconnection channels for vehicle height adjustment during camping, climbing, and descending.

[0040] Furthermore, the control valve group consists of a distribution valve assembly and several solenoid switching valves.

[0041] The intelligent suspension system of this embodiment can not only realize vehicle body lifting, multiple stiffness modes, stepless damping adjustment, four-wheel leveling, hill driving posture adjustment, cross-axle and rough road driving adjustment, but also adaptively suppress the body roll, pitch and vertical bumps in each stiffness mode. The invention has a simple structure and good adaptability to driving conditions, making the vehicle more suitable for multi-condition driving including off-road driving.

[0042] Example 2: This example provides an intelligent hydraulic four-wheel interconnected active suspension system, such as... Figure 1 As shown, it mainly includes:

[0043] Multiple hydraulic branches are respectively set at both ends of the front and rear axles of the vehicle to adjust the damping, stiffness and height of the vehicle suspension;

[0044] Wheel-end hydraulic cylinders (15, 16, 17, 18), specifically, are single-cylinder shock absorbers with spring elements. The piston is provided with a throttle orifice and a valve plate. The piston rod is hollow in the middle and blocked at the lower end. A side hole is provided at the root of the blockage to lead to the upper chamber (rod chamber) of the hydraulic cylinder. A side hole is left at the bottom of the lower chamber (rodless chamber) oil cylinder for interconnection between the upper and lower chambers of the four-wheel hydraulic cylinder.

[0045] The control valve assembly consists of a distribution valve assembly 3 and several interconnected switching valves (9, 10, 13, 14, 19, 20);

[0046] The distribution valve assembly consists of branch oil circuit switching valves (3.1, 3.2, 3.4, 3.5) and gate valves (3.3, 3.6) for each wheel branch. It is used to switch the oil filling and discharging of each hydraulic cylinder. When there is no vehicle height adjustment, all valves in the distribution valve assembly are closed.

[0047] Interconnected switching valves, all of which are electromagnetic switching valves, are used for the on / off switching of interconnections;

[0048] The stiffness adjuster (such as 4 and 5 on the left front hydraulic branch) is an assembly that integrates an electromagnetic switch and an accumulator. The stiffness adjustment is turned on and off by switching the electromagnetic switch on and off. The two stiffness adjusters on each side of the four wheels can be adjusted at the same time to achieve three levels of stiffness adjustment and one stiffness lock. If the first stiffness adjuster and the second stiffness adjuster on the hydraulic cylinder oil line of each wheel end are turned on and off respectively, multi-level adjustment of the stiffness of each wheel end can be performed.

[0049] Damping regulators (such as 6 and 8 on the left front hydraulic branch), the damping regulators are damping regulators dominated by electromagnetic proportional valves, which can realize stepless adjustment of damping, such as 6 and 8 on the left front hydraulic branch (Note 8 can be cancelled as needed);

[0050] The power supply unit, which includes oil pump set 1 and accumulator 2, is the power source for raising the vehicle body.

[0051] like Figure 2 The diagram shown is a control block diagram of the active suspension system in this embodiment, where ASC is the active suspension controller, IBC is the integrated brake control unit, VIU is the vehicle information unit, EPS is the electric power steering system, MSW is the vehicle height adjustment system, and FR / FL / RR / RL represent the right front wheel / left front wheel / right rear wheel / left rear wheel of the vehicle, respectively.

[0052] Furthermore, its specific functional description (taking the 1 / 4 suspension and front axle as examples) is as follows:

[0053] 1) Vehicle body height increase:

[0054] With the distribution valve assembly 3 open (all 6 solenoid valves open) and the front and rear interconnection valves 9 and 10 closed, the vehicle body is raised according to the set height for each mode under the combined action of the oil pump group 1 and the accumulator 2 (switch open). The fully open solenoid valves ensure that the vehicle body raising is not affected in the event of a malfunction in one of the oil circuit solenoid valves in the distribution valve assembly 3 (such as a malfunction in 3.1 or 3.2). Closing the front and rear interconnection valves 9 and 10 decouples the front and rear axle vehicle body raising.

[0055] 2) Vehicle body lowering:

[0056] The distribution valve assembly 3 is opened (all 6 solenoid switch valves are open), the front and rear interconnection switch valves 9 and 10 are closed, the oil pump group 1 and accumulator 2 are shut down (switch closed), the oil return port in the oil pump group is mechanically opened, and the oil flows back to the oil tank by gravity, the vehicle body is lowered, and the vehicle height is controlled according to the vehicle height position set in each mode.

[0057] 3) Stiffness adjustment:

[0058] By turning the electromagnetic switch valves of the first stiffness adjuster 4 and the second stiffness adjuster 5 on and off, three-level stiffness (2x2-1) adjustment can be achieved.

[0059] 4) Damping adjustment:

[0060] Signals from the wheel-side Z-axis acceleration and the six-axis accelerometer on the vehicle body are calculated by ASC to adjust the electromagnetic proportional valves of damping regulators 6 and 8 (or only 6) in real time, thereby achieving intelligent damping adjustment.

[0061] 5) Camping leveling:

[0062] Close the interconnection switch valves 9, 10, 13, 14, 19, and 20 to disconnect the four-wheel interconnection. Activate the vehicle body lifting function in conjunction with the distribution valve assembly 3 to adjust the height of each suspension individually. Based on the level gauge readings, adjust the height of each wheel section to level the vehicle body.

[0063] 6) Adjustment for hill climbing:

[0064] Close interconnection switch valves 9 and 10 to disconnect the front and rear interconnection, activate switch valves 3.4, 3.5, and 3.6, close switch valves 3.1, 3.2, and 3.3, activate the vehicle body lifting function to raise the rear axle, and adjust the rear axle height according to the level gauge reading.

[0065] 7) Adjusting the elevation for downhill driving:

[0066] Close interconnection switch valves 9 and 10 to disconnect the front and rear interconnection; close switch valves 3.4, 3.5, and 3.6; activate switch valves 3.1, 3.2, and 3.3 to activate the vehicle body lifting function, raising the front axle; and adjust the vehicle height of the front axle section according to the level gauge reading.

[0067] 8) Normal driving control:

[0068] With the distribution valve assembly 3 closed (all 6 solenoid switch valves closed), front and rear interconnection switch valves 9 and 10 closed, oil pump assembly closed, and accumulator closed, the system can adaptively suppress body roll, pitch, and vertical sway in each stiffness mode and damping adjustment.

[0069] 9) Cross-axle and rough road driving control:

[0070] Distributor valve assembly 3 is closed (all 6 solenoid valves are closed), front and rear interconnection valves 9 and 10 are open, oil pump assembly is closed, and accumulator is closed. This results in almost no torsional torque on the vehicle body, reducing the chance of tires leaving the ground and improving the vehicle's off-road performance.

[0071] Example 3: Based on the same inventive concept, this example also provides a control method for the intelligent hydraulic four-wheel interconnected active suspension system as described above, such as... Figure 3 As shown, the specific steps include the following:

[0072] S1, Vehicle body lifting control: Open all solenoid valves in the distribution valve assembly, close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve, and then open the oil pump group in the power supply unit to raise the vehicle body to the preset height one.

[0073] S2, Vehicle body descent control: Open all solenoid valves in the distribution valve assembly, close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve, then close the oil pump group in the power supply unit and open the oil return port of the oil pump group, so that the vehicle body descends to the preset height two.

[0074] S3, Stiffness Adjustment Control: Multi-level adjustment of the stiffness of each wheel end is achieved by opening and closing the first stiffness adjuster and the second stiffness adjuster on the hydraulic cylinder oil circuit of each wheel end respectively.

[0075] S4, Damping Adjustment Control: Based on the acceleration sensor signals of each wheel and the six-axis acceleration sensor signals of the vehicle body, the electromagnetic proportional valve of the damping adjuster on the hydraulic cylinder oil circuit of each wheel end is adjusted in real time to adjust the damping of each wheel end;

[0076] S5, Camping Leveling Control: Close all interconnection switch valves to cut off the vehicle's four-wheel interconnection. Based on the onboard level indicator signal, individually open the branch oil circuit switch valves of each wheel. In conjunction with the opening and closing of the power supply unit, adjust the suspension height of each wheel individually to level the vehicle body as a whole.

[0077] S6, Hill Climbing Driving Height Control: Close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve to disconnect the front and rear wheels of the vehicles. Open the left rear oil circuit switch valve, the right rear oil circuit switch valve and the rear door valve. At the same time, close the left front oil circuit switch valve, the right front oil circuit switch valve and the front door valve. Then, turn on the oil pump unit in the power supply unit to raise the rear axle of the vehicle to the preset height of three.

[0078] S7, Downhill driving height control: Close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve to disconnect the front and rear wheels of the vehicles. Open the left front oil circuit switch valve, the right front oil circuit switch valve and the front door valve. At the same time, close the left rear oil circuit switch valve, the right rear oil circuit switch valve and the rear door valve. Then, turn on the oil pump group in the power supply unit to raise the front axle of the vehicle to the preset height of four.

[0079] S8, Normal Driving Control: All solenoid valves, oil pump group, accumulator, and left and right front-to-rear interconnection switch valves in the distribution valve assembly are closed, which can adaptively suppress body roll, pitch and vertical bumps under each stiffness mode and damping adjustment.

[0080] S9, Cross-Axle and Rough Road Driving Control: All solenoid valves, oil pump group and accumulator in the distribution valve assembly are closed, and the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve are open. This generates almost no torsional torque on the vehicle body, reduces the chance of the tires leaving the ground and improves the vehicle's off-road performance.

[0081] Example 4: Based on the same inventive concept, this example also provides a manual / automatic vehicle, which is equipped with the intelligent hydraulic four-wheel interconnected active suspension system as described above.

[0082] Furthermore, all parts of this application that are not described in detail are the same as or implemented using existing technology.

[0083] In summary:

[0084] 1. This invention proposes an intelligent hydraulic four-wheel interconnected active suspension system. By rationally arranging the interconnected hydraulic pipelines of the hydraulic cylinders at the four wheel ends of the vehicle, and in conjunction with stiffness adjusters, damping adjusters, control valve groups, and power supply units, it can not only realize vehicle body lifting, multiple stiffness modes, stepless damping adjustment, four-wheel leveling, slope driving posture adjustment, cross-axle and rough road driving adjustment, but also adaptively suppress the body roll, pitch and vertical bumps in each stiffness mode. Moreover, the overall structure is simple and easy to debug and maintain.

[0085] 2. This invention proposes a control method for an intelligent hydraulic four-wheel interconnected active suspension system. By combining information from various vehicle sensors to intelligently control the control valve group, the vehicle can adapt to various driving conditions, including off-road driving, thereby improving the vehicle's driving adaptability and driving comfort.

[0086] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method for an intelligent hydraulic four-wheel interconnected active suspension system, characterized in that, The suspension system includes lifting hydraulic cylinders, stiffness adjusters, damping adjusters, control valve groups, and power supply units located at the four wheel ends of the vehicle. The upper and lower chambers of the four wheel-end hydraulic cylinders are interconnected through multiple hydraulic lines, and each wheel-end hydraulic cylinder is equipped with a stiffness adjuster and a damping adjuster on its hydraulic line. The control valve group includes a distribution valve assembly and multiple interconnected switching valves. The multiple interconnected switching valves are located on the interconnected hydraulic lines of the four wheel-end hydraulic cylinders. The distribution valve assembly is connected to the power supply unit, which includes an oil pump group and an accumulator. The control method includes the following steps: The vehicle body height control opens all the solenoid valves in the distribution valve assembly and closes the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve. Then, it turns on the oil pump group in the power supply unit to raise the vehicle body to the preset height. The vehicle body descent control opens all the solenoid valves in the distribution valve assembly and closes the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve. Then, it shuts down the oil pump group in the power supply unit and simultaneously opens the oil return port of the oil pump group through mechanical linkage, so that the vehicle body descends to the preset height two. Stiffness adjustment control is achieved by separately opening and closing the first stiffness adjuster and the second stiffness adjuster on the hydraulic cylinder oil circuit of each wheel end, thereby performing multi-level adjustment of the stiffness of each wheel end. Damping adjustment control adjusts the damping of each wheel end in real time by adjusting the electromagnetic proportional valve of the damping adjuster on the hydraulic cylinder oil circuit of each wheel end according to the acceleration sensor signals of each wheel edge and the six-axis acceleration sensor signals of the vehicle body. Camping leveling control closes all interconnection switch valves, cuts off the vehicle's four-wheel interconnection, and opens the branch oil circuit switch valves of each wheel individually according to the signal from the vehicle level instrument. In conjunction with the opening and closing of the power supply unit, it performs individual adjustment of the suspension height of each wheel to level the vehicle body as a whole. The ramp climbing driving height control closes the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve, cutting off the connection between the front and rear wheels of the vehicles. It opens the left rear oil circuit switch valve, the right rear oil circuit switch valve and the rear door valve, while closing the left front oil circuit switch valve, the right front oil circuit switch valve and the front door valve. Then, it turns on the oil pump unit in the power supply unit to raise the rear axle of the vehicle to the preset height of three. Downhill driving height control: Close the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve to disconnect the front and rear wheels of the vehicles. Open the left front oil circuit switch valve, the right front oil circuit switch valve and the front door valve. At the same time, close the left rear oil circuit switch valve, the right rear oil circuit switch valve and the rear door valve. Then turn on the oil pump group in the power supply unit to raise the front axle of the vehicle to the preset height of four. Under normal driving control, all solenoid valves, oil pump group, accumulator, as well as the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve in the distribution valve assembly are in the closed state; For cross-axle and rough road driving control, all solenoid valves, oil pumps, and accumulators in the distribution valve assembly are closed, while the left front-to-rear interconnection switch valve and the right front-to-rear interconnection switch valve are open.

2. The control method for an intelligent hydraulic four-wheel interconnected active suspension system according to claim 1, characterized in that, The upper and lower chambers of the four wheel-end hydraulic cylinders are specifically interconnected as follows: the upper chamber of the left front wheel-end hydraulic cylinder is connected to the lower chamber of the right front wheel-end hydraulic cylinder via pipe one; the lower chamber of the left front wheel-end hydraulic cylinder is connected to the upper chamber of the right front wheel-end hydraulic cylinder via pipe two; the upper chamber of the left rear wheel-end hydraulic cylinder is connected to the lower chamber of the right rear wheel-end hydraulic cylinder via pipe three; and the lower chamber of the left rear wheel-end hydraulic cylinder is connected to the upper chamber of the right rear wheel-end hydraulic cylinder via pipe four. Furthermore, pipe two and pipe four are connected via pipe five, and pipe one and pipe three are connected via pipe six.

3. The control method for an intelligent hydraulic four-wheel interconnected active suspension system according to claim 2, characterized in that, The distribution valve assembly includes a left front oil circuit switch valve, a right front oil circuit switch valve, a left rear oil circuit switch valve, and a right rear oil circuit switch valve. The left front oil circuit switch valve is connected to the first pipeline through oil pipe one, the right front oil circuit switch valve is connected to the second pipeline through oil pipe two, the left rear oil circuit switch valve is connected to the third pipeline through oil pipe three, and the right rear oil circuit switch valve is connected to the fourth pipeline through oil pipe four. Furthermore, a front valve is provided between oil pipe one and oil pipe two, and a rear valve is provided between oil pipe three and oil pipe four.

4. The control method for an intelligent hydraulic four-wheel interconnected active suspension system according to claim 2, characterized in that, Pipeline 1, Pipeline 2, Pipeline 3, and Pipeline 4 are respectively equipped with a left-right interconnection switch valve on the right side of the front suspension, a left-right interconnection switch valve on the left side of the front suspension, a left-right interconnection switch valve on the right side of the rear suspension, and a left-right interconnection switch valve on the left side of the rear suspension.

5. The control method for an intelligent hydraulic four-wheel interconnected active suspension system according to claim 2, characterized in that, Pipeline 5 and Pipeline 6 are respectively equipped with a left-side front-to-back interconnection switch valve and a right-side front-to-back interconnection switch valve.

6. The control method for an intelligent hydraulic four-wheel interconnected active suspension system according to claim 2, characterized in that, Each of the pipelines 1, 2, 3, and 4 is equipped with two stiffness regulators and two damping regulators. The stiffness regulator contains an electromagnetic switch and an energy accumulator, and the damping regulator contains an electromagnetic proportional valve.

7. The control method for an intelligent hydraulic four-wheel interconnected active suspension system according to claim 1, characterized in that, The upper chamber of the wheel-end hydraulic cylinder is a rodless chamber, and the lower chamber is a rod-type chamber; all four wheel-end hydraulic cylinders are connected in parallel with their corresponding spring elements to jointly support the weight of the vehicle body.

8. The control method for an intelligent hydraulic four-wheel interconnected active suspension system according to claim 1, characterized in that, The lifting hydraulic cylinders, stiffness adjusters, damping adjusters, control valve groups, and power supply units at the four wheel ends are all electrically connected to the active suspension controller.

9. A vehicle with both manual and automatic transmissions, characterized in that: The intelligent hydraulic four-wheel interconnected active suspension system control method as described in any one of claims 1 to 8 is adopted.

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