Control method and device of semi-active suspension system and computer readable storage medium

Abstract

The invention discloses a control method and device of a semi-active suspension system and a computer readable storage medium. The method comprises the steps that when a vehicle runs, the current road surface roughness is determined, and the current wheel slip rate is determined; and based on the road surface roughness and the wheel slip rate, the damping force of an electric control shock absorber assembly of the semi-active suspension system is adjusted. The damping force of the vehicle electric control shock absorber assembly of the semi-active suspension system can be dynamically adjusted in real time, so that the running stability of a vehicle is improved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle control, and particularly relates to a control method, device and computer-readable storage medium for a semi-active suspension system. Background Art

[0002] With the rapid development of the automotive industry and the continuous increase in vehicle driving speed, people have put forward higher requirements for vehicle driving safety and ride comfort. The control method of the damping of the vehicle semi-active suspension system plays a crucial role in the performance of the suspension, directly affecting the handling stability, ride comfort and driving safety of the vehicle. For a vehicle semi-active suspension system, it is necessary to continuously adjust its damping according to the vehicle speed and the current road surface roughness of the vehicle, so as to achieve the best ride comfort on the premise of ensuring the safe driving of the vehicle. In the current mainstream control scheme of the semi-active suspension system, the damping force of the shock absorber is dynamically adjusted only when functions such as ABS and TCS are triggered under emergency braking conditions. This will result in a relatively late intervention in the damping adjustment of the shock absorber, affecting the driving stability of the whole vehicle.

[0003] The above content is only used to assist in understanding the technical solution of the present application, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] Embodiments of the present application provide a control method, device and computer-readable storage medium for a semi-active suspension system, aiming to perform real-time dynamic adjustment of the damping force of the vehicle electronic control shock absorber assembly of the semi-active suspension system, so as to improve the driving stability of the vehicle.

[0005] Embodiments of the present application provide a control method for a semi-active suspension system, the control method of the semi-active suspension system includes:

[0006] When the vehicle is driving, determine the current road surface roughness and determine the current wheel slip ratio;

[0007] Based on the road surface roughness and the wheel slip ratio, adjust the damping force of the electronic control shock absorber assembly of the semi-active suspension system.

[0008] Optionally, the determining the current road surface roughness includes:

[0009] Obtain the wheel acceleration within a preset driving duration, and determine the road surface roughness according to the wheel acceleration;

[0010] The determining the current wheel slip ratio includes:

[0011] Obtain the current wheel speed and the wheel rolling radius, and obtain the actual vehicle speed of the vehicle;

[0012] Determine the current wheel slip ratio based on the wheel rotation speed, the wheel rolling radius, and the actual vehicle speed.

[0013] Optionally, the obtaining the wheel acceleration within a preset driving duration and determining the road surface roughness based on the wheel acceleration includes:

[0014] Obtain the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within a preset driving duration;

[0015] Determine the road surface roughness based on the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within the preset driving duration.

[0016] Optionally, the step of determining the road surface roughness based on the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within the preset driving duration includes:

[0017] Square the vertical acceleration of the left front wheel collected at each moment within the preset driving duration to obtain the squared value of the vertical acceleration of the left front wheel corresponding to each moment within the preset driving duration; perform an averaging process on the squared values of the vertical acceleration of the left front wheel corresponding to each moment within the preset driving duration to obtain the average value of the vertical acceleration of the left front wheel; perform a square root process on the average value of the vertical acceleration of the left front wheel to obtain the root mean square of the vertical acceleration of the left front wheel; and

[0018] Square the vertical acceleration of the right front wheel collected at each moment within the preset driving duration to obtain the squared value of the vertical acceleration of the right front wheel corresponding to each moment within the preset driving duration; perform an averaging process on the squared values of the vertical acceleration of the right front wheel corresponding to each moment within the preset driving duration to obtain the average value of the vertical acceleration of the right front wheel; perform a square root process on the average value of the vertical acceleration of the right front wheel to obtain the root mean square of the vertical acceleration of the right front wheel;

[0019] Perform an averaging process on the root mean square of the vertical acceleration of the left front wheel and the root mean square of the vertical acceleration of the right front wheel to obtain the road surface roughness.

[0020] Optionally, the step of determining the current wheel slip ratio based on the wheel rotation speed, the wheel rolling radius, and the actual vehicle speed includes:

[0021] For each wheel, determine the theoretical vehicle speed of the wheel based on the wheel rotation speed and the wheel rolling radius;

[0022] Determine the vehicle speed difference between the actual vehicle speed and the theoretical vehicle speed of the wheel;

[0023] Determine the wheel slip ratio of the wheel based on the ratio between the vehicle speed difference and the actual vehicle speed.

[0024] Optionally, the step of adjusting the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system based on the road surface roughness and the wheel slip ratio includes:

[0025] When the wheel slip ratio is greater than or equal to a preset slip ratio, adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system based on the road surface roughness and the wheel slip ratio.

[0026] Optionally, the step of adjusting the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system based on the road surface roughness and the wheel slip ratio when the wheel slip ratio is greater than or equal to a preset slip ratio includes:

[0027] When the wheel slip ratio is greater than or equal to a preset slip ratio, determine the target working current of the electronically controlled shock absorber assembly according to the road surface roughness and the wheel slip ratio;

[0028] Control the current working current of the electronically controlled shock absorber assembly to be adjusted to the target working current to adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

[0029] Optionally, determining the target working current of the electronically controlled shock absorber assembly according to the road surface roughness and the wheel slip ratio includes:

[0030] Determine the first current gain corresponding to the wheel slip ratio according to the wheel slip ratio, the first calibration value, and the second calibration value;

[0031] Determine the second current gain corresponding to the road surface roughness according to the road surface roughness, the third calibration value, and the fourth calibration value;

[0032] Obtain the base current of the electronically controlled shock absorber;

[0033] Determine the target working current of the electronically controlled shock absorber assembly according to the first current gain, the second current gain, and the base current.

[0034] In addition, to achieve the above object, the present application also provides a control device for a semi-active suspension system, which includes: at least one wheel speed sensor, at least one wheel acceleration sensor, at least one electronically controlled shock absorber assembly, and a semi-active suspension control unit. The semi-active suspension system control unit is respectively connected to the wheel speed sensor, the wheel acceleration sensor, and the electronically controlled shock absorber assembly, and is used to process the data collected by the wheel speed sensor and the wheel acceleration sensor to obtain the current road surface roughness and the current wheel slip ratio, and adjust the damping force of the electronically controlled shock absorber assembly based on the current road surface roughness and the current wheel slip ratio;

[0035] The semi-active suspension system control unit includes: a memory, a processor, and a control program of the semi-active suspension system stored on the memory and running on the processor. When the control program of the semi-active suspension system is executed by the processor, the steps of the control method of the semi-active suspension system as described above are implemented.

[0036] In addition, to achieve the above object, the present application also provides a computer-readable storage medium, on which a control program of the semi-active suspension system is stored. When the control program of the semi-active suspension system is executed by a processor, the steps of the control method of the semi-active suspension system as described above are implemented.

[0037] The technical solution of the present application provides a control method, device and computer-readable storage medium for a semi-active suspension system. By determining the road surface roughness and wheel slip ratio during vehicle driving, and then adjusting the damping force of the electronically controlled shock absorber assembly in the semi-active suspension system according to the road surface roughness and wheel slip ratio, it is possible to perform real-time dynamic adjustment of the damping force of the electronically controlled shock absorber assembly based on the changes in the road surface roughness and vehicle slip ratio during vehicle driving, improving vehicle driving stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic structural diagram of a control device for a semi-active suspension system according to an embodiment of the present application;

[0039] Figure 2 It is another schematic structural diagram of a control device for a semi-active suspension system according to an embodiment of the present application;

[0040] Figure 3 It is a schematic flowchart of the first embodiment of the control method for the semi-active suspension system of the present application;

[0041] Figure 4 It is a schematic flowchart of the third embodiment of the control method for the semi-active suspension system of the present application;

[0042] Figure 5 It is a schematic flowchart of the fourth embodiment of the control method for the semi-active suspension system of the present application;

[0043] Figure 6 It is a detailed flowchart of step S121 in the fifth embodiment of the control method for the semi-active suspension system of the present application;

[0044] Figure 7 It is a detailed flowchart of step S1211 in the fifth embodiment of the control method for the semi-active suspension system of the present application.

[0045] The realization, functional features and advantages of the present application will be further described in conjunction with embodiments with reference to the accompanying drawings. The above-mentioned accompanying drawings are only drawings of one embodiment and not all of the application. Detailed Implementation Manner

[0046] To better understand the above technical solution, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art.

[0047] In view of the above problems, the present application proposes a control method for a semi-active suspension system. The main technical solutions of the present application include: when the vehicle is running, determining the current road surface roughness and determining the current wheel slip ratio; based on the road surface roughness and the wheel slip ratio, adjusting the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system. It is possible to perform real-time dynamic adjustment of the damping force of the electronically controlled shock absorber assembly based on the changes in the road surface roughness and the vehicle slip ratio during the vehicle running process, and improve the vehicle running stability.

[0048] As Figure 1 shown, Figure 1 is a schematic structural diagram of the hardware operating environment of the control device for the semi-active suspension system involved in the embodiment solution of the present application.

[0049] The semi-active suspension system is a vehicle suspension system that combines the characteristics of traditional passive suspension systems and active suspension systems. Compared with traditional passive suspension systems, the semi-active suspension system has a higher response speed and better ride comfort; compared with active suspension systems, the semi-active suspension system is more simplified and cost-saving. In the semi-active suspension system, the real-time adjustment of the suspension system stiffness and damping is achieved by using adjustable shock absorbers or pneumatic components. These shock absorbers or pneumatic components can adjust their working states according to the feedback signals of sensors or control algorithms to adapt to different road conditions and driving requirements.

[0050] Optionally, the semi-active suspension system of the present application includes an electromagnetic semi-active suspension system, a liquid or gas adjustable semi-active suspension system, and a preloaded semi-active suspension system. The working principles of each type of semi-active suspension system will be introduced in detail below:

[0051] Electromagnetic semi-active suspension system: uses an electromagnetic damper to adjust the damping characteristics of the suspension system. When the sensor detects the movement of the vehicle or the change in road surface conditions, the control unit will change the current of the electromagnetic damper, thereby adjusting the damping force.

[0052] Liquid or gas adjustable semi-active suspension system: Utilizes adjustable liquid or gas shock absorbers to change the stiffness and damping of the suspension system. By controlling valves or air pressure, the flow of liquid or gas within the shock absorber can be altered, thereby achieving real-time adjustment of the suspension system.

[0053] Preload adjustable semi-active suspension system: Uses an adjustable spring preload device to change the stiffness of the suspension system. By changing the compression amount of the spring, the stiffness characteristics of the suspension system can be adjusted to a certain extent to adapt to different road conditions and vehicle driving states.

[0054] The semi-active suspension system can adjust the characteristics of the suspension system in real time according to road conditions and driving requirements. While providing better ride comfort, it can also improve the handling and stability of the vehicle. This makes the semi-active suspension system widely used in high-end cars and sports cars.

[0055] The control device of the semi-active suspension system of the present application includes: at least one wheel speed sensor, at least one wheel acceleration sensor, at least one electronically controlled shock absorber assembly, and a semi-active suspension control unit. The semi-active suspension system control unit is respectively connected to the wheel speed sensor, the wheel acceleration sensor, and the electronically controlled shock absorber assembly, and is used to process the data collected by the wheel speed sensor and the wheel acceleration sensor and the current vehicle speed to obtain the current road surface roughness and the current wheel slip ratio, and adjust the damping force of the electronically controlled shock absorber assembly based on the current road surface roughness and the current wheel slip ratio.

[0056] In this embodiment, the wheel speed sensor is used to collect the wheel speed. The wheel acceleration sensor is used to collect the vertical acceleration of the wheel. The electronically controlled shock absorber assembly is used to provide damping for the vibration generated during the movement of the semi-active suspension system and the spring rebound, improving the stability of the vehicle during driving.

[0057] Exemplarily, as Figure 2 shown, the control device of the semi-active suspension system of the present application includes:

[0058] Four wheel speed sensors, namely the left front wheel speed sensor, the right front wheel speed sensor, the left rear wheel speed sensor, and the right rear wheel speed sensor respectively; among them, the left front wheel speed sensor is used to collect the wheel speed of the left front wheel, the right front wheel speed sensor is used to collect the wheel speed of the right front wheel; the left rear wheel speed sensor is used to collect the wheel speed of the left rear wheel; the right rear wheel speed sensor is used to collect the wheel speed of the right rear wheel.

[0059] Two wheel vertical acceleration sensors, namely the left front wheel vertical acceleration sensor and the right front wheel vertical acceleration sensor. By arranging vertical acceleration sensors on the left front wheel and the right front wheel in this application, it is possible to detect changes in road surface roughness earliest, determine the road condition changes, respond in a timely manner, and control the electronic control shock absorber immediately when detecting road surface changes, improving the control speed and ensuring the driving stability of the vehicle. Optionally, in addition to using wheel vertical acceleration sensors, this application can also use wheel lateral acceleration sensors or vehicle longitudinal acceleration sensors.

[0060] Four electronic control shock absorber assemblies, namely the left front electronic control shock absorber assembly, the right front electronic control shock absorber assembly, the left rear electronic control shock absorber assembly, and the left rear electronic control shock absorber assembly. By arranging corresponding electronic control shock absorber assemblies for each wheel, it is possible to adjust each wheel individually, improve the adjustment accuracy of the damping force, and ensure the driving stability and comfort of the vehicle.

[0061] A semi-active suspension control unit, which is connected to the above four wheel speed sensors and two wheel vertical acceleration sensors for obtaining the data collected by these sensors. The semi-active suspension control unit is also connected to the above four electronic control shock absorber assemblies for controlling each electronic control shock absorber assembly.

[0062] The semi-active suspension control unit also obtains the vehicle CAN signal (i.e., the actual vehicle speed), and this actual vehicle speed will be sent to the semi-active suspension control unit together with the data collected by the above sensors for calculation to achieve the effect of adjusting the damping force of the electronic control shock absorber assembly in real time.

[0063] As Figure 1 shown, the semi-active suspension control unit of this application includes: a processor and a memory.

[0064] Optionally, the memory can be a high-speed RAM memory or a stable memory, such as a disk memory. Optionally, the memory can also be a storage device independent of the aforementioned processor.

[0065] Optionally, the semi-active suspension control unit of this application can also include a user interface, a network interface, and a communication bus. Among them, the communication bus is used to realize the connection and communication between these components. The user interface can include a display screen and an input unit such as a keyboard. Optionally, the user interface can also include a standard wired interface and a wireless interface. The network interface can optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The user interface is mainly used to connect to a terminal and communicate data with the terminal; the network interface is mainly used to connect to a background server and communicate data with the background server.

[0066] Those skilled in the art can understand, Figure 1The structure of the control device of the semi-active suspension system shown does not constitute a limitation on the control device of the semi-active suspension system, and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0067] As Figure 1 shown, a memory as a storage medium may include a control program for the semi-active suspension system.

[0068] Optionally, the memory of the present application may further include an operating system, a network communication module, and a user interface module. Among them, the operating system is a program that manages and controls the hardware and software resources of the control device of the semi-active suspension system, and the operation of the control program of the semi-active suspension system and other software or programs.

[0069] In Figure 1 the control device of the semi-active suspension system shown, the processor may be used to call the control program stored in the memory for the semi-active suspension system.

[0070] In this embodiment, the control device of the semi-active suspension system includes: a memory, a processor, and a control program for the semi-active suspension system stored on the memory and executable on the processor. Among them, when the processor calls the control program stored in the memory for the semi-active suspension system, the following operations are performed:

[0071] When the vehicle is running, determine the current road surface roughness and determine the current wheel slip ratio;

[0072] Based on the road surface roughness and the wheel slip ratio, adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

[0073] As Figure 3 shown, in the first embodiment of the present application, the control method of the semi-active suspension system of the present application includes the following steps:

[0074] Step S110, when the vehicle is running, determine the current road surface roughness and determine the current wheel slip ratio.

[0075] Optionally, the semi-active suspension control unit of the present application can, during the vehicle's driving process, acquire and process the data collected by the sensors in real time to determine the current road surface roughness and wheel slip ratio. Alternatively, the semi-active suspension control unit can, during the vehicle's driving process, acquire and process the data collected by the sensors at regular intervals to determine the current road surface roughness and vehicle slip ratio. Alternatively, the semi-active suspension control unit can also, during the vehicle's driving process, when detecting that the external environment is a preset environment, acquire and process the data collected by the sensors to determine the current road surface roughness and wheel slip ratio. For example, when detecting that the external environment is night, it can acquire and analyze the data collected by the sensors in real time and dynamically adjust the damping force of the electronically controlled shock absorber assembly in real time to improve the vehicle driving stability in the night scenario.

[0076] In this embodiment, the road surface roughness is an important index in the road conditions. It describes the smoothness or unevenness of the road surface and has a direct impact on vehicle driving and driving experience.

[0077] The road surface roughness is usually determined by the following factors:

[0078] Longitudinal unevenness: This refers to the undulation of the road in the vehicle driving direction. Longitudinal unevenness can cause the vehicle to experience a bumpy feeling during driving and affect the suspension system and vehicle stability.

[0079] Transverse unevenness: This refers to the undulation of the road in the transverse direction. Transverse unevenness can cause the vehicle to experience side sway or drift during turning and affect the handling and driving stability.

[0080] Vertical unevenness: This refers to the vertical height undulation of the road surface. Vertical unevenness can cause the vehicle to experience a bumpy feeling during driving and affect the riding comfort.

[0081] Different road surface roughnesses will have different impacts on vehicle driving. For example, in the case of a rough road surface, the vehicle's suspension system needs better shock absorption ability to absorb vibrations; in the case of a smooth road surface, the vehicle's handling and driving stability will be better. Therefore, for drivers, it is very important to understand and evaluate the road surface roughness, which can help them make appropriate driving adjustments to ensure driving safety and riding comfort.

[0082] In this embodiment, the current road surface roughness can be determined by the acceleration data collected by an acceleration sensor. For example, the acceleration data collected by one of a vertical acceleration sensor, a longitudinal acceleration sensor, or a lateral acceleration sensor can be used to determine the current road surface roughness; the current road surface roughness can also be determined by the data measured by a laser rangefinder; the current road surface roughness can also be determined by the image data collected by a video sensor; the current road surface roughness can also be determined by the degree of wheel slip; the current road surface roughness can also be determined by the height data collected by a height sensor. Each method will be introduced in detail below:

[0083] (1) Measurement by acceleration sensor: By installing an acceleration sensor on the vehicle, the acceleration changes of the vehicle body on different road sections can be recorded, and thus the road surface roughness can be deduced. This method usually requires accurate positioning and measurement of the vehicle's motion state to obtain accurate results.

[0084] (2) Measurement by laser rangefinder: By installing a laser rangefinder on the vehicle, the height distribution of the road surface can be scanned, and thus the road surface roughness can be deduced. This method can provide high-resolution road surface data, but it requires a long scanning time and high equipment costs.

[0085] (3) Video image processing: By using an in-vehicle camera to capture road surface images, and then using image processing algorithms to analyze the texture and geometric features of the road surface, the road surface roughness can be deduced. This method requires high computing power and algorithm complexity, but has the advantages of low equipment costs and easy implementation.

[0086] (4) Wheel slip measurement: By measuring the degree of wheel slip during vehicle driving, the friction coefficient and roughness of the road surface can be deduced. This method requires accurate modeling of the vehicle's dynamic behavior and needs to be tested and verified under different road conditions.

[0087] In this embodiment, the slip ratio reflects the friction characteristics between the vehicle tires and the ground. When the tires slip, the slip ratio will increase. By detecting and analyzing the slip ratio, the traction, braking performance, and steering stability of the vehicle can be evaluated. The wheel slip ratio during vehicle driving can be measured using a variety of methods, usually involving vehicle dynamics and sensor measurement techniques. The following are some common measurement methods:

[0088] (1) Wheel speed sensor: The wheel speed sensor installed on the vehicle tire can measure the actual wheel rotation speed of the wheel. By comparing the wheel rotation speeds of different tires, the wheel slip ratio can be calculated. Commonly used wheel speed sensors include magnetic sensors, Hall sensors, etc.

[0089] (2) Inertial Measurement Unit (IMU): The IMU can measure the acceleration and angular velocity of the vehicle. By analyzing the vehicle's motion state, the wheel slip condition can be inferred. Combining with the vehicle dynamics model, the wheel slip ratio can be calculated.

[0090] (3) Differential sensor: Some vehicles are equipped with differential sensors, which can directly measure the rotational speed difference of the differential in the vehicle drive system, and thus indirectly obtain the wheel slip ratio information.

[0091] (4) Vision sensor: Use cameras or other vision sensors to detect the motion of the wheels on the road surface. Through image processing and computer vision technologies, the wheel slip condition can be analyzed.

[0092] Step S120, based on the road surface roughness and the wheel slip ratio, adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

[0093] In this embodiment, the damping force of the electronically controlled shock absorber assembly refers to the damping effect provided by the electronically controlled shock absorber assembly on the vibrations generated during the movement of the vehicle suspension system and the spring rebound. The magnitude of the damping force directly affects the stability, ride comfort, and handling performance of the vehicle during driving. The damping force of the electronically controlled shock absorber assembly is usually composed of two parts:

[0094] Compression damping: When the vehicle suspension system compresses due to uneven road surfaces or vehicle movements such as acceleration and braking, the damping force provided by the electronically controlled shock absorber assembly is called compression damping. Its function is to suppress the excessive compression of the suspension system and slow down the rising speed of the vehicle body.

[0095] Rebound damping: When the vehicle suspension system rebounds due to passing through bumpy road surfaces or vehicle passing over speed bumps, etc., the damping force provided by the electronically controlled shock absorber assembly is called rebound damping. Its function is to suppress the excessive rebound of the suspension system and slow down the descending speed of the vehicle body.

[0096] The damping force of the electronically controlled shock absorber assembly is generated by an internal damper (such as a liquid damper or a pneumatic damper). The liquid or gas in the damper consumes energy through flow when subjected to vibration, thereby providing a damping effect. An appropriate damping force of the electronically controlled shock absorber assembly can keep the vehicle stable during driving, reduce the up and down jolts of the vehicle body, and improve ride comfort; at the same time, it can also improve the handling performance of the vehicle, reduce the excessive swing of the suspension system, and ensure the stability of the vehicle during turning and sudden acceleration / sudden braking.

[0097] In this embodiment, during the vehicle driving process, when it is detected that the road surface roughness is more severe, the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system is greater; when the wheel slip ratio is greater, the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system is greater, so that during the vehicle driving process, the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system can be adjusted in real time according to the road surface roughness and the wheel slip ratio, ensuring the stability of the vehicle.

[0098] According to the above technical solution of this embodiment, the present application determines the road surface roughness and the wheel slip ratio during vehicle driving, and then adjusts the damping force of the electronically controlled shock absorber assembly in the semi-active suspension system according to the road surface roughness and the wheel slip ratio, and can perform real-time dynamic adjustment of the damping force of the electronically controlled shock absorber assembly based on the changes in the road surface roughness and the vehicle slip ratio during the vehicle driving process, improving the driving stability of the vehicle.

[0099] Further, based on the first embodiment, in the second embodiment of the present application, in step S110: determining the current road surface roughness includes:

[0100] Step S111, obtaining the wheel acceleration within a preset driving duration, and determining the road surface roughness according to the wheel acceleration.

[0101] In this embodiment, the preset driving duration can be determined according to the actual situation. Determining the road surface roughness according to the wheel acceleration within the preset driving duration can reflect the road surface roughness within a certain driving distance and improve the accuracy of the road surface roughness.

[0102] In this embodiment, the wheel acceleration at each moment within the preset driving duration can be obtained, the average value of the wheel acceleration at each moment is calculated, and the average value of the wheel acceleration is obtained. The road surface roughness is determined according to the average value of the wheel acceleration. Determining the road surface roughness through the average value of the wheel acceleration within the preset driving duration makes the calculated road surface roughness more accurate.

[0103] In step S110: determining the current wheel slip ratio includes:

[0104] Step S112, obtaining the current wheel speed and the wheel rolling radius, and obtaining the actual vehicle speed of the vehicle.

[0105] In this embodiment, the current wheel speed of the present application can be the rotational speed of the wheel corresponding to the current moment, which can be obtained by collecting through a wheel speed sensor. The wheel rolling radius refers to the distance from the contact point of the tire with the ground to the center of the tire during driving, and can also be called the effective radius of the tire. It has a great influence on the performance and driving characteristics of the vehicle. The wheel rolling radius will change with the wear of the tire because tire wear will cause problems such as a decrease in tire height and deformation of the tire shape. When the tire is worn excessively, the rolling radius will become smaller, which will affect aspects such as the vehicle's speed, fuel consumption, and driving stability.

[0106] In this embodiment, the actual vehicle speed of the vehicle can be obtained through the CAN bus. The actual vehicle speed refers to the true driving speed measured by devices such as a speedometer.

[0107] Step S113, determine the current wheel slip ratio according to the wheel speed, the wheel rolling radius, and the actual vehicle speed.

[0108] In this embodiment, for a given road surface and tire, the higher the actual vehicle speed of the vehicle, the smaller the wheel slip ratio. When the adhesion force between the wheel and the road surface is insufficient (such as on a wet or slippery road surface or during a sharp turn), the wheel is prone to slipping and the slip ratio will increase. At this time, the actual vehicle speed may be affected. For example, during emergency braking, the slip ratio of the wheel increases, resulting in an increase in the braking distance and a slower deceleration of the vehicle speed, making the vehicle more unstable.

[0109] In this embodiment, the theoretical vehicle speed can be determined according to the wheel speed and the wheel rolling radius, and the difference between the theoretical vehicle speed and the actual vehicle speed can be represented by the slip ratio. The slip ratio can be positive or negative. When the slip ratio is a positive value, it means that the actual vehicle speed is greater than the theoretical speed, and when the slip ratio is zero, it means that the theoretical speed is equal to the actual speed.

[0110] According to the above technical solution in this embodiment, the present application determines the current wheel slip ratio according to the wheel speed, the wheel rolling radius, and the actual vehicle speed. By monitoring and analyzing the slip ratio, the traction force, braking performance, and steering stability of the vehicle can be evaluated.

[0111] Further, based on the second embodiment, referring to Figure 4 , in the third embodiment of the present application, step S111 includes:

[0112] Step S1111, obtain the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within a preset driving duration.

[0113] In this embodiment, the present application sets vertical acceleration sensors on the left front wheel and the right front wheel to collect the vertical accelerations of the left front wheel and the right front wheel.

[0114] In this embodiment, the present application obtains the acceleration in the vertical direction of the wheel by setting a vertical acceleration sensor. Since the acceleration in the vertical direction of the wheel characterizes the vertical undulation of the road surface, the vertical unevenness can cause a bumpy feeling during vehicle driving and affect the riding comfort. Therefore, the bumpy feeling generated during vehicle driving can be evaluated by collecting the vertical acceleration.

[0115] In this embodiment, by respectively setting vertical acceleration sensors on the left front wheel and the right front wheel, the change in road surface roughness can be detected earliest, the road condition change can be determined, and timely response can be made. When the road surface change is detected, the electronic control shock absorber can be controlled immediately to improve the response speed of the electronic control shock absorber and ensure the driving stability of the vehicle.

[0116] Step S1112: Determine the road surface roughness according to the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within the preset driving duration.

[0117] In this embodiment, the vertical acceleration of the left front wheel collected by the left front wheel vertical acceleration sensor at each moment within the preset driving duration can be obtained, and the vertical acceleration of the right front wheel collected by the right front wheel vertical acceleration sensor at each moment within the preset driving duration can be obtained; relevant calculations are performed according to the vertical acceleration of the left front wheel collected at each moment and the vertical acceleration of the right front wheel collected at each moment, so as to obtain the current road surface roughness.

[0118] According to the above technical solution, in this embodiment, by determining the road surface roughness according to the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within the preset driving duration, the electronic control shock absorber can be controlled immediately when the road surface height change is detected, the response speed of the electronic control shock absorber can be improved, and the driving stability of the vehicle can be ensured.

[0119] In other embodiments, the present application is not limited to the left front vertical acceleration sensor and the right front vertical acceleration sensor, and the vertical acceleration can also be collected by the vertical acceleration sensors of other wheels. In addition, the present application is not limited to collecting the vertical acceleration, and the lateral acceleration or the longitudinal acceleration can also be collected. The lateral acceleration is used to evaluate the side roll or drift generated during vehicle turning, which affects the handling performance and driving stability. The longitudinal acceleration is used to evaluate the bumpy feeling generated during vehicle driving, which affects the suspension system and vehicle stability. It can also be to collect the vertical acceleration, the lateral acceleration and the longitudinal acceleration simultaneously to improve the accuracy of the road surface roughness evaluation result.

[0120] Optionally, step S1112 includes:

[0121] Step S11121: Square the vertical acceleration of the left front wheel collected at each moment within the preset driving duration to obtain the squared value of the vertical acceleration of the left front wheel corresponding to each moment within the preset driving duration; perform an averaging process on the squared values of the vertical acceleration of the left front wheel corresponding to each moment within the preset driving duration to obtain the average value of the vertical acceleration of the left front wheel; perform a square root operation on the average value of the vertical acceleration of the left front wheel to obtain the root mean square of the vertical acceleration of the left front wheel.

[0122] Step S11122: Square the vertical acceleration of the right front wheel collected at each moment within the preset driving duration to obtain the squared value of the vertical acceleration of the right front wheel corresponding to each moment within the preset driving duration; perform an averaging process on the squared values of the vertical acceleration of the right front wheel corresponding to each moment within the preset driving duration to obtain the average value of the vertical acceleration of the right front wheel; perform a square root operation on the average value of the vertical acceleration of the right front wheel to obtain the root mean square of the vertical acceleration of the right front wheel.

[0123] Step S11123: Perform an averaging process on the root mean square of the vertical acceleration of the left front wheel and the root mean square of the vertical acceleration of the right front wheel to obtain the road surface roughness.

[0124] In this embodiment, the following formula can be used to calculate the current road surface roughness:

[0125]

[0126] where a FLi is the vertical acceleration information of the left front wheel collected by the left front wheel vertical acceleration sensor at the i-th moment, and a FRi is the vertical acceleration information of the right front wheel collected by the right front wheel vertical acceleration sensor at the i-th moment. N represents the preset driving duration.

[0127] The root mean square of the vertical acceleration of the left front wheel and the root mean square of the vertical acceleration of the right front wheel calculated in this application can be used to evaluate the road surface roughness, which is convenient for subsequent control of the electronic control shock absorber of the vehicle suspension system.

[0128] Further, based on the second embodiment, referring to Figure 5 , in the fourth embodiment of this application, step S113 includes: for each wheel, determine the theoretical vehicle speed corresponding to the wheel according to the wheel speed and the wheel rolling radius, and determine the wheel slip rate according to the theoretical vehicle speed and the actual vehicle speed.

[0129] Step S1131: For each wheel, determine the theoretical vehicle speed of the wheel according to the wheel speed and the wheel rolling radius.

[0130] In this embodiment, by collecting the rotational speeds of the left front wheel, right front wheel, left rear wheel, and right rear wheel, the wheel slip ratio of each wheel is solved according to the following formula. For each wheel, the relevant steps of steps S1131 - S1133 are used to calculate the wheel slip ratio of the corresponding wheel. This embodiment takes the calculation of the wheel slip ratio of one of the wheels as an example.

[0131] In this embodiment, the rotational speeds and rolling radii of different wheels may be different. The rotational speed of each wheel can be measured by wheel speed sensors provided at different wheel positions. The rolling radius of the wheel can be measured by existing means, which will not be elaborated here.

[0132] Optionally, the theoretical vehicle speed corresponding to the wheel can be determined according to the product of the wheel rotational speed and the wheel rolling radius.

[0133] Step S1132, determine the vehicle speed difference between the actual vehicle speed and the theoretical vehicle speed of this wheel.

[0134] In this embodiment, the slip ratio has positive and negative values. When the slip ratio is a positive value, it means that the actual vehicle speed is greater than the theoretical speed, that is, the vehicle speed difference is greater than zero. And when the slip ratio is zero, it means that the theoretical speed is equal to the actual speed, that is, the vehicle speed difference is equal to zero.

[0135] Step S1133, determine the wheel slip ratio of this wheel according to the ratio between the vehicle speed difference and the actual vehicle speed.

[0136] In this embodiment, the smaller the wheel slip ratio is when the actual vehicle speed is greater; the larger the wheel slip ratio is when the actual vehicle speed is smaller. The wheel slip ratio can be calculated using the following formula:

[0137]

[0138] where λ i is the wheel slip ratio at the i-th moment; V x is the actual vehicle speed; r is the wheel rolling radius; ω is the wheel rotational speed, and rω represents the theoretical vehicle speed.

[0139] In this embodiment, according to the above technical solution, the present application calculates the wheel slip ratio corresponding to each wheel respectively according to the rotational speed of each wheel, the wheel rolling radius, and the actual vehicle speed of the vehicle, improving the accuracy of the calculation result of the wheel slip ratio corresponding to each wheel.

[0140] Further, based on the above embodiments, in the fifth embodiment of the present application, step S120 includes the following steps:

[0141] Step S121, when the wheel slip ratio is greater than or equal to a preset slip ratio, based on the road surface roughness and the wheel slip ratio, adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

[0142] In this embodiment, the preset slip ratio can be calibrated or set according to different vehicle types. When the wheel slip ratio is greater than or equal to the preset slip ratio, it indicates that a certain wheel is slipping. To ensure the driving stability of the vehicle, it is necessary to adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

[0143] In this embodiment, when the wheel slip ratio corresponding to a certain wheel is greater than or equal to the preset slip ratio, based on the road surface roughness and the wheel slip ratio, adjust the damping force of the electronically controlled shock absorber assembly of the wheel corresponding to the wheel slip ratio greater than or equal to the preset slip ratio, so as to perform targeted adjustment on this wheel.

[0144] According to the above technical solution, this embodiment can, by setting the trigger condition of the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system, timely respond and adjust the damping force of the electronically controlled shock absorber assembly when the current wheel slip ratio deviates, and improve the driving stability of the vehicle.

[0145] Optionally, referring to Figure 6 , step S121 includes:

[0146] Step S1211, when the wheel slip ratio is greater than or equal to the preset slip ratio, determine the target working current of the electronically controlled shock absorber assembly according to the road surface roughness and the wheel slip ratio.

[0147] Step S1212, control the current working current of the electronically controlled shock absorber assembly to be adjusted to the target working current, so as to adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

[0148] In this embodiment, after the semi-active suspension system control unit obtains the wheel slip ratios of each wheel, it compares the wheel slip ratios of each wheel with the preset slip ratio respectively, determines the wheel with the wheel slip ratio greater than or equal to the preset slip ratio, and adjusts the damping force of the electronically controlled shock absorber assembly corresponding to this wheel.

[0149] In this embodiment, the present application achieves the effect of adjusting the damping force of the electronically controlled shock absorber assembly by changing the working current of the electronically controlled shock absorber. When the working current is larger, the damping force of the electronically controlled shock absorber assembly is larger; when the working current is smaller, the damping force of the electronically controlled shock absorber assembly is smaller.

[0150] In this embodiment, when determining the wheel corresponding to a wheel slip ratio greater than or equal to a preset slip ratio, according to the road surface roughness and the wheel slip ratio corresponding to the wheel, the target working current of the electronically controlled shock absorber assembly corresponding to the wheel is determined. When the electronically controlled shock absorber assembly corresponding to the wheel operates according to the target working current, it can effectively alleviate the unstable situation of vehicle driving and improve the stability of the vehicle.

[0151] Optionally, the current working current of the electronically controlled shock absorber assembly can be gradually adjusted to the target working current according to a preset current step, while improving the vehicle stability, the driving comfort is also improved.

[0152] In other embodiments, when the wheel slip ratio of a certain wheel is less than the preset slip ratio, the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system of the wheel is not adjusted, and the electronically controlled shock absorber assembly of the wheel still operates according to the base current; optionally, the base current can be set according to the actual situation.

[0153] Optionally, referring to Figure 7 , for the target working current of the electronically controlled shock absorber assembly of each wheel, perform the relevant adjustments of steps S12111 - S12114, that is, in step S1211: determining the target working current of the electronically controlled shock absorber assembly according to the road surface roughness and the wheel slip ratio includes:

[0154] Step S12111, determine the first current gain corresponding to the wheel slip ratio according to the wheel slip ratio, the first calibration value, and the second calibration value.

[0155] In this embodiment, the first calibration value and the second calibration value can be calibrated and set according to different vehicle types. The product of the wheel slip ratio and the first calibration value can be determined, and the first current gain corresponding to the wheel slip ratio is determined according to the sum of the product and the second calibration value. There is a first functional relationship between the wheel slip ratio and the first current gain corresponding to the wheel slip ratio, and the first functional relationship is as follows:

[0156] G λi = k1 * λ i + b1;

[0157] Wherein, K1 represents the first calibration value, b1 represents the second calibration value, λ i represents the wheel slip ratio, and G λi represents the first current gain corresponding to the wheel slip ratio.

[0158] Step S12112, determine the second current gain corresponding to the road surface roughness according to the road surface roughness, the third calibration value, and the fourth calibration value.

[0159] In this embodiment, the third calibration value and the fourth calibration value can be calibrated and set according to different vehicle types. The product of the road surface roughness and the third calibration value can be determined, and the second current gain corresponding to the road surface roughness can be determined according to the sum of the product and the fourth calibration value. The road surface roughness and the second current gain corresponding to the road surface roughness have a second functional relationship, and the second functional relationship is as follows:

[0160]

[0161] wherein, K2 represents the third calibration value, b2 represents the fourth calibration value, and R index represents the road surface roughness, and represents the second current gain corresponding to the road surface roughness.

[0162] Step S12113: Obtain the base current of the electronic control shock absorber.

[0163] In this embodiment, the base current of the electronic control shock absorber assembly refers to the current when the current electronic control shock absorber assembly is operating. This base current can be preset with a default value according to the actual situation.

[0164] Step S12114: Determine the target working current of the electronic control shock absorber assembly according to the first current gain, the second current gain, and the base current.

[0165] In this embodiment, the target working current of the electronic control shock absorber assembly refers to the driving current of the electronic control shock absorber assembly. The target working current of the electronic control shock absorber assembly can be determined according to the product of the first current gain, the second current gain, and the base current. The specific calculation formula is:

[0166]

[0167] wherein, I req is the target working current of the electronic control shock absorber assembly, and I base is the base current.

[0168] According to the above technical solution in this embodiment, since the functional relationship between the wheel slip ratio and the first current gain is established, and the functional relationship between the road surface roughness and the second current gain is established, through the established functional relationships, the first current gain and the second current gain can be quickly calculated, thereby improving the calculation efficiency of the target working current of the electronic control shock absorber assembly and improving the control efficiency of the damping force of the electronic control shock absorber assembly.

[0169] This application provides an embodiment of a control method for a semi-active suspension system. It should be noted that although the logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than here.

[0170] Based on the same inventive concept, an embodiment of the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a control program for a semi-active suspension system. When the control program of the semi-active suspension system is executed by a processor, it implements each step of the control method of the semi-active suspension system as described above and can achieve the same technical effects. To avoid repetition, it will not be elaborated here.

[0171] Since the storage medium provided by the embodiment of the present application is the storage medium adopted for implementing the method of the embodiment of the present application, based on the method introduced in the embodiment of the present application, those skilled in the art can understand the specific structure and variations of the storage medium, so it will not be elaborated here. Any storage medium adopted by the method of the embodiment of the present application belongs to the scope of protection of the present application.

[0172] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of another identical element in the process, method, article or system including that element.

[0173] The serial numbers of the above embodiments of the present application are only for description and do not represent the superiority or inferiority of the embodiments.

[0174] Through the description of the above embodiments, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium as described above (such as ROM / RAM, magnetic disk, optical disc), and includes several instructions to enable a terminal device (which can be a mobile phone, computer, server, TV, or network device, etc.) to execute the methods described in various embodiments of the present application.

[0175] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present application by the same token.

Claims

1. A control method for a semi-active suspension system, characterized in that The control method of the semi-active suspension system includes: When the vehicle is running, determining the current road surface roughness and determining the current wheel slip ratio; Based on the road surface roughness and the wheel slip ratio, adjusting the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

2. The control method of the semi-active suspension system according to claim 1, characterized in that The determining of the current road surface roughness includes: Obtaining the wheel acceleration within a preset driving duration and determining the road surface roughness according to the wheel acceleration; The determining of the current wheel slip ratio includes: Obtaining the current wheel speed and the wheel rolling radius, and obtaining the actual vehicle speed; Based on the wheel speed, the wheel rolling radius and the actual vehicle speed, determining the current wheel slip ratio.

3. The control method of the semi-active suspension system according to claim 2, characterized in that, The obtaining of the wheel acceleration within a preset driving duration and determining the road surface roughness according to the wheel acceleration includes: Obtaining the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within a preset driving duration; Based on the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within the preset driving duration, determining the road surface roughness.

4. The control method of the semi-active suspension system according to claim 3, characterized in that, The step of determining the road surface roughness based on the vertical acceleration of the left front wheel and the vertical acceleration of the right front wheel within the preset driving duration includes: Squaring the vertical acceleration of the left front wheel collected at each moment within the preset driving duration to obtain the squared value of the vertical acceleration of the left front wheel corresponding to each moment within the preset driving duration; averaging the squared values of the vertical acceleration of the left front wheel corresponding to each moment within the preset driving duration to obtain the average value of the vertical acceleration of the left front wheel; taking the square root of the average value of the vertical acceleration of the left front wheel to obtain the root mean square value of the vertical acceleration of the left front wheel; and Squaring the vertical acceleration of the right front wheel collected at each moment within the preset driving duration to obtain the squared value of the vertical acceleration of the right front wheel corresponding to each moment within the preset driving duration; averaging the squared values of the vertical acceleration of the right front wheel corresponding to each moment within the preset driving duration to obtain the average value of the vertical acceleration of the right front wheel; taking the square root of the average value of the vertical acceleration of the right front wheel to obtain the root mean square value of the vertical acceleration of the right front wheel; Averaging the root mean square value of the vertical acceleration of the left front wheel and the root mean square value of the vertical acceleration of the right front wheel to obtain the road surface roughness.

5. The control method of the semi-active suspension system according to claim 2, characterized in that, The step of determining the current wheel slip ratio based on the wheel speed, the wheel rolling radius and the actual vehicle speed includes: For each wheel, based on the wheel speed and the wheel rolling radius, determining the theoretical vehicle speed of the wheel; Determining the vehicle speed difference between the actual vehicle speed and the theoretical vehicle speed of the wheel; Based on the ratio between the vehicle speed difference and the actual vehicle speed, determining the wheel slip ratio of the wheel.

6. The control method of the semi-active suspension system according to any one of claims 1-5, characterized in that, The step of adjusting the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system based on the road surface roughness and the wheel slip ratio includes: When the wheel slip ratio is greater than or equal to the preset slip ratio, adjusting the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system based on the road surface roughness and the wheel slip ratio.

7. The control method of the semi-active suspension system according to claim 6, characterized in that, When the wheel slip ratio is greater than or equal to a preset slip ratio, the step of adjusting the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system based on the road surface roughness and the wheel slip ratio includes: When the wheel slip ratio is greater than or equal to a preset slip ratio, determine the target working current of the electronically controlled shock absorber assembly according to the road surface roughness and the wheel slip ratio; Control the current working current of the electronically controlled shock absorber assembly to be adjusted to the target working current to adjust the damping force of the electronically controlled shock absorber assembly of the semi-active suspension system.

8. The control method of the semi-active suspension system according to claim 7, characterized in that, The determining the target working current of the electronically controlled shock absorber assembly according to the road surface roughness and the wheel slip ratio includes: Determine a first current gain corresponding to the wheel slip ratio according to the wheel slip ratio, a first calibration value, and a second calibration value; Determine a second current gain corresponding to the road surface roughness according to the road surface roughness, a third calibration value, and a fourth calibration value; Obtain the base current of the electronically controlled shock absorber; Determine the target working current of the electronically controlled shock absorber assembly according to the first current gain, the second current gain, and the base current.

9. A control device for a semi-active suspension system, characterized in that, The control device of the semi-active suspension system includes: at least one wheel speed sensor, at least one wheel acceleration sensor, at least one electronically controlled shock absorber assembly, and a semi-active suspension control unit. The semi-active suspension system control unit is respectively connected to the wheel speed sensor, the wheel acceleration sensor, and the electronically controlled shock absorber assembly, and is used to process the data collected by the wheel speed sensor and the wheel acceleration sensor to obtain the current road surface roughness and the current wheel slip ratio, and adjust the damping force of the electronically controlled shock absorber assembly based on the current road surface roughness and the current wheel slip ratio; The semi-active suspension system control unit includes: a memory, a processor, and a control program of the semi-active suspension system stored on the memory and running on the processor. When the control program of the semi-active suspension system is executed by the processor, the steps of the control method of the semi-active suspension system according to any one of claims 1-8 are implemented.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a control program of the semi-active suspension system. When the control program of the semi-active suspension system is executed by a processor, the steps of the control method of the semi-active suspension system according to any one of claims 1-8 are implemented.

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