Equipment and methods for controlling vehicle suspension

Abstract

An apparatus and method for controlling a vehicle suspension, which takes into account virtual tire damping to control a variable damper, the apparatus comprising: a variable damper mounted between the vehicle body and the wheels; a first acceleration sensor mounted at each corner of the vehicle body and measuring the vertical acceleration of the vehicle body angle; a second acceleration sensor mounted at each wheel of the vehicle and measuring the vertical acceleration of the wheel; and a controller that estimates road surface roughness based on the vertical acceleration of the vehicle body angle and the vertical acceleration of the wheels, determines the required damping force for virtual tire damping based on the estimated road surface roughness, and adjusts the damping force of the variable damper based on the determined required damping force for virtual tire damping.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0095340, filed on July 30, 2020, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] The present invention relates to an apparatus and method for controlling a vehicle suspension, which takes into account virtual tire damping to control a variable damper. Background Technology

[0004] Vehicles are equipped with a suspension system that absorbs shocks between the vehicle body and the wheels (axles) and maintains tire contact with the road surface. The suspension (system) includes arms or links that control wheel movement, springs that absorb and regulate shocks, and dampers, also known as shock absorbers. Because springs and dampers operate only within physically defined, specific ranges and move passively between the vehicle body and wheels, they affect the vehicle's ride comfort, handling, and / or steering response. Therefore, techniques for adjusting suspension characteristics (e.g., spring characteristics, damper characteristics, etc.) have been investigated to provide optimal ride comfort, handling, and / or steering response for the vehicle driver.

[0005] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of the invention and should not be construed as an endorsement of prior art known to those skilled in the art or any form of advice. Summary of the Invention

[0006] Various aspects of the present invention aim to provide an apparatus and method for controlling a vehicle suspension, which can take into account virtual tire damping to control a variable damper in order to minimize the relative speed between the wheel and the road surface.

[0007] The technical problems to be solved by the present invention are not limited to those described above, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art through the following descriptions relating to various exemplary embodiments of the present invention.

[0008] According to various aspects of the present invention, an apparatus for controlling a vehicle suspension includes: a variable damper mounted between the vehicle body and the wheels; a first acceleration sensor mounted at each corner of the vehicle body and measuring the vertical acceleration of the vehicle body angle; a second acceleration sensor mounted at each wheel of the vehicle and measuring the vertical acceleration of the wheel; and a controller that estimates road surface roughness based on the vertical acceleration of the vehicle body angle and the vertical acceleration of the wheels, determines a required damping force for virtual tire damping based on the estimated road surface roughness, and adjusts the damping force of the variable damper based on the determined required damping force for virtual tire damping.

[0009] The controller can filter the measurement signals to remove noise from the measurement signals output from the first and second acceleration sensors, and obtain the vehicle body angular vertical velocity and wheel vertical velocity by integration.

[0010] The controller can estimate road surface roughness by using a Kalman filter.

[0011] The controller can be configured to determine the ceiling control gain, virtual tire damping control gain, and passive damping force based on road surface roughness and vehicle driving information obtained via the controller area network (CAN).

[0012] The controller can be configured to: determine the vertical velocity, pitch velocity, and roll velocity of the vehicle's center of gravity based on the vertical velocity of the vehicle's body angle and the vertical velocity of the wheels; determine the force and torque required for roof control based on the vertical velocity, pitch velocity, and roll velocity of the vehicle's center of gravity; and allocate the required damping force for each vehicle angle based on the force and torque required for roof control.

[0013] The controller can be configured to determine the required damping force for virtual tire damping by using road surface roughness and virtual tire damping control gain.

[0014] The controller can be configured to determine the final required damping force for each corner by integrating the required damping force for each body corner, the required damping force for virtual tire damping, and the required passive damping force.

[0015] The controller can be configured to determine the current to be applied to the variable damper based on the final required damping force at each corner.

[0016] The controller can be configured to control the damping force of the variable damper by adjusting the current signal applied to the solenoid valve of the variable damper.

[0017] According to various aspects of the present invention, a method for controlling a vehicle suspension includes: measuring the vehicle body angular vertical acceleration and the wheel vertical acceleration by means of a first acceleration sensor and a second acceleration sensor respectively mounted on the vehicle body and the wheel; estimating road surface roughness based on the vehicle body angular vertical acceleration and the wheel vertical acceleration; determining the damping force required for virtual tire damping based on the road surface roughness; and adjusting the damping force of a variable damper based on the damping force required for virtual tire damping.

[0018] The measurement may include filtering to remove noise from the measurement signals output from the first and second accelerometers, and integrating to obtain the vehicle body angular vertical velocity and wheel vertical velocity.

[0019] Estimating road surface roughness may include: acquiring vehicle driving information via Controller Area Network (CAN); and determining the ceiling control gain, virtual tire damping control gain, and passive damping force based on the vehicle driving information and road surface roughness.

[0020] The method may further include: determining the vertical velocity, pitch velocity, and roll velocity of the vehicle body center of gravity based on the vertical velocity of the vehicle body angle and the vertical velocity of the wheels; determining the force and torque required for roof control based on the vertical velocity, pitch velocity, and roll velocity of the vehicle body center of gravity and the roof control gain; and allocating the required damping force for each vehicle body angle based on the force and torque required for roof control.

[0021] Determining the required damping force for virtual tire damping can include using road surface roughness and virtual tire damping control gain to determine the required damping force for virtual tire damping.

[0022] Adjusting the damping force of a variable damper can include determining the final required damping force for each angle by integrating the required damping force for each vehicle body angle, the required damping force for virtual tire damping, and the required passive damping force.

[0023] Adjusting the damping force of a variable damper can include determining the current to be applied to the variable damper based on the final required damping force at each angle.

[0024] Adjusting the damping force of a variable damper can also include controlling the damping force of the variable damper by adjusting the current signal applied to the solenoid valve of the variable damper.

[0025] The methods and apparatus of the present invention have other features and advantages, which will be set forth in more detail from or in the accompanying drawings, which are incorporated herein and in the following detailed description, together serving to explain certain principles of the invention. Attached Figure Description

[0026] Figure 1This is a block diagram illustrating a device for controlling a vehicle suspension according to an exemplary embodiment of the present invention;

[0027] Figure 2 It is shown Figure 1 The block diagram showing the functional configuration of the controller is shown.

[0028] Figure 3 This is a concept diagram illustrating a 1 / 4 scale vehicle model according to an exemplary embodiment of the present invention;

[0029] Figure 4 This is a flowchart illustrating a method for controlling a vehicle suspension according to an exemplary embodiment of the present invention; and

[0030] Figure 5 This is a block diagram illustrating a computational system for performing a method of controlling a vehicle suspension according to various exemplary embodiments of the present invention.

[0031] It is understood that the accompanying drawings are not necessarily drawn to scale and present slightly simplified representations of various features illustrating the basic principles of the invention. Specific design features of the invention as included herein, such as specific dimensions, orientations, positions, and shapes, will be determined in part by the particular intended application and environment of use.

[0032] In the accompanying drawings, reference numerals throughout the several figures refer to the same or equivalent parts of the invention. Detailed Implementation

[0033] Reference will now be made in detail to various embodiments of the invention, examples of which are illustrated in the accompanying drawings and described below. Although the invention will be described in conjunction with exemplary embodiments thereof, it should be understood that this specification is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments thereof, but also various alternatives, modifications, equivalents and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0034] In the following, various exemplary embodiments of the present invention will be described in detail with reference to the exemplary accompanying drawings. When adding reference numerals to the components of each drawing, it should be noted that even if the same or equivalent components are shown in other drawings, they are indicated by the same reference numerals. Furthermore, in describing exemplary embodiments of the present invention, detailed descriptions of well-known features or functions will be omitted to avoid unnecessarily obscuring the gist of the invention.

[0035] In describing components of various exemplary embodiments of the present invention, terms such as first, second, "A", "B", (a), (b), etc., may be used. These terms are intended only to distinguish one component from another, and do not limit the nature, order, or sequence of the constituent components. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those skilled in the art to which the various exemplary embodiments of the present invention pertain. Such terms as defined in a general dictionary should be interpreted as having the same meaning as in the context relevant to the relevant field, and should not be interpreted as having an ideal or overly formal meaning unless explicitly defined herein.

[0036] Figure 1 This is a block diagram illustrating a device for controlling a vehicle suspension according to an exemplary embodiment of the present invention. Figure 2 It is shown Figure 1 The block diagram shown illustrates the functional configuration of the controller. Figure 3 This is a conceptual diagram illustrating a 1 / 4 scale vehicle model according to an exemplary embodiment of the present invention.

[0037] Reference Figure 1 The device 100 for controlling the vehicle suspension includes a sensor 100, a variable damper 200, and a controller 300.

[0038] Sensor 100 is mounted on the vehicle body and wheels to measure the vertical acceleration of the vehicle body angle and the vertical acceleration of the wheels. Sensor 100 may include at least three or more first acceleration sensors 110 and at least two or more second acceleration sensors 120. The first acceleration sensors 110 may be attached to top mounting portions at the four corners of the vehicle body to measure the vertical acceleration of the angles respectively. For example, the first acceleration sensors 110 may be mounted at the left front and right front corners and the left rear and right rear corners of the vehicle body, or they may be mounted at a point at the left front and right front corners and the left rear and right rear corners respectively. The second acceleration sensors 120 may be attached to the steering knuckles of the wheels to measure the vertical acceleration of the wheels. Furthermore, sensor 100 may also include wheel speed sensors, steering angle sensors, lateral acceleration sensors, etc.

[0039] A variable damper 200 can be installed between the vehicle body and the wheels (axles) to reduce the impact or vibration transmitted from the road surface to the tires when the vehicle is in motion. The variable damper 200 can be installed between the vehicle body and the left and right front wheels and the left and right rear wheels, respectively. The variable damper 200 may include a solenoid valve for adjusting the damping force. The variable damper 200 can adjust the actual damping force by controlling the operation of the solenoid valve. In the present case, a variable damper 200 using a solenoid valve as an actuator is described as an example, but a stepper motor or the like can also be used as the actuator. A continuous damping control (CDC) damper can be used as the variable damper 200, but the exemplary embodiment is not limited to this, and various variable dampers can be used.

[0040] The controller 300 is an electronic control unit (ECU) that controls the damping force of the variable damper 200 in the suspension. It controls the damping force of the variable damper 200 using ceiling control logic and virtual tire damping control logic. The controller 300 can acquire the vertical acceleration of the vehicle body angle and the vertical acceleration of the wheels using sensor 100. In the current case, the vertical acceleration of the vehicle body angle can include the vertical acceleration of the left front corner, the right front corner, the left rear corner, and the right rear corner. The vertical acceleration of the wheels can include the vertical acceleration of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel. The controller 300 can determine the required ceiling damping force and the required virtual tire damping force (the required damping force of the virtual tire) based on the vertical acceleration of the vehicle body angle and the vertical acceleration of the wheels. The controller 300 can adjust the amount of current applied to the variable damper 200 based on the required damping force of the ceiling and the required damping force of the virtual tire. The damping force of the variable damper 200 can vary in response to the amount of current applied to it.

[0041] The controller 300 may include a processor 301 and a memory 302. The processor 301 controls the overall operation of the controller 300. The processor 301 may be implemented using at least one of an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a programmable logic device (PLD), a field-programmable gate array (FPGA), a central processing unit (CPU), a microcontroller, and / or a microprocessor. The memory 302 may be a non-transitory storage medium that stores instructions executed by the processor 301. The memory 302 may be implemented using at least one of flash memory, a hard disk, a secure digital storage card (SD card), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable ROM (EEPROM), erasable programmable ROM (EPROM), a storage medium (recording medium), a register, etc.

[0042] In the following text, reference will be made to Figure 2 Describe the functional configuration of controller 300.

[0043] The controller 300 may include a signal measurement device 310, a signal processing device 320, a state quantity estimation device 330, a control gain determination device 340, a damping force control device 350, and a damper current application device 360. In the present case, each configuration may represent logic that performs a specific function, and each logic may be executed by the processor 301.

[0044] The signal measuring device 310 can acquire (receive) signals measured by the first acceleration sensor 110 and the second acceleration sensor 120. The signal measuring device 310 can measure the vertical acceleration of the vehicle body at each corner using the first acceleration sensor 110. The signal measuring device 310 can measure the vertical acceleration of each wheel using the second acceleration sensor 120.

[0045] The signal measurement device 310 can acquire vehicle driving information via a controller area network (CAN). Vehicle driving information may include vehicle speed, steering angle, deceleration, acceleration, and / or lateral acceleration. The signal measurement device 310 can also acquire vehicle driving information via CAN communication through other ECUs and / or sensors installed in the vehicle (e.g., wheel speed sensors, steering angle sensors, and / or lateral acceleration sensors).

[0046] The signal processing device 320 can post-process the signals (information, data) acquired by the signal measurement device 310. The signal processing device 320 can remove noise from the vehicle vertical acceleration signals at each angle and the wheel vertical acceleration signals of each wheel, measured by the first and second acceleration sensors 110 and 120. In other words, the signal processing device 320 can filter out noise from the measurement signals (detection signals) received by the first and second acceleration sensors. Furthermore, the signal processing device 320 can determine the vehicle vertical velocity at each angle and the wheel vertical velocity of each wheel by integrating the vehicle vertical acceleration at each angle and the wheel vertical acceleration of each wheel. The signal processing device 320 can also determine the vehicle displacement information at each angle and the wheel displacement information of each wheel by integrating the vehicle vertical velocity at each angle and the wheel vertical velocity of each wheel.

[0047] The state quantity estimation device 330 can estimate road surface roughness, damper stroke speed, etc. in real time by using the vehicle body angular vertical acceleration, wheel vertical acceleration, and signals post-processed by the signal processing device 320 (e.g., vehicle body angular vertical velocity and wheel vertical velocity). The state quantity estimation device 330 can estimate road surface roughness by using a Kalman filter, a vehicle model, etc.

[0048] The control gain determination device 340 can determine the roof control gain, virtual tire damping control gain, and passive damping control gain based on vehicle driving information. That is, the control gain determination device 340 can determine the roof control gain, virtual tire damping control gain, and passive damping control gain based on vehicle driving information such as vehicle speed, vertical acceleration, lateral acceleration, steering angle, and road surface information.

[0049] The damping force control device 350 can determine the vehicle center of gravity, the required damping force for the wheel canopy, and the required damping force for the virtual tire damping based on information measured by the signal measurement device 310, information post-processed by the signal processing device 320, and information estimated by the state quantity estimation device 330. Furthermore, the damping force control device 350 can determine the final damper control force for each corner and the current to be applied to the variable damper 200 to meet the required damping force.

[0050] The damping force control device 350 can determine the vertical velocity, pitch angular velocity, and roll angular velocity of the vehicle's center of gravity based on the vehicle's vertical velocity at each angle and vehicle specification information. The vehicle specification information can be stored in the memory 302 and may include wheelbase, track width, distance between the front wheels and the vehicle's center of gravity, distance between the rear wheels and the vehicle's center of gravity, etc. The memory 302 can pre-store information about the attachment positions (mounting positions) of the first and second acceleration sensors 110 and 120.

[0051] The damping force control device 350 can determine the required damping force for the roof in each direction based on the three-directional velocities of the vehicle's center of gravity (e.g., vertical velocity, pitch angular velocity, and roll angular velocity) and the roof control gain. Specifically, the damping force control device 350 can determine the force and torque required for roof control based on the three-directional velocities of the vehicle's center of gravity and the roof control gain determined by the control gain determination device 340. In other words, the damping force control device 350 can determine the required damping force for the roof in each direction, proportional to the three-directional velocities of the vehicle's center of gravity and the roof control gain. The damping force control device 350 can distribute the required roof damping force for each vehicle body corner based on the determined required force and torque. The damping force control device 350 can determine the required virtual tire damping force for each wheel by using estimated road surface roughness and virtual tire damping control gain.

[0052] The damping force control device 350 can integrate the determined required damping force for the ceiling, the required damping force for the virtual tire damping, and the passive damping force determined by the control gain determination device 340 to determine the final required damping force (i.e., the damper control force) for each angle. The damping force control device 350 can determine the current applied to the damper based on the determined final damping force required for each angle.

[0053] The damper current application device 360 ​​can generate current based on the damper application current determined by the damping force control device 350, and apply the current to the variable damper 200. The damping force of the variable damper 200 can be changed corresponding to the current applied by the damper current application device 360. The damper current application device 360 ​​can control the operation of the solenoid valve by adjusting the amount of current applied to the solenoid valve of the variable damper 200. When the solenoid valve of the variable damper 200 is operating, the actual damping force at each corner of the vehicle body can be changed. The damper current application device 360 ​​can prevent damage to the variable damper 200 by limiting the maximum current applied to the solenoid valve of the variable damper 200.

[0054] The following section will describe in detail how to determine the required damping force for each wheel.

[0055] First, the damping force control device 350 can determine the required damping force for each wheel used for canopy control.

[0056] In the case of roof control, unlike virtual tire damping control, the control quantity can be determined based on vehicle body motion. The control gain determination device 340 can determine the roof body's three-directional (e.g., vertical, pitch, and roll) control gain C based on vehicle driving information. sky_heave C sky_pitch and C sky_ro11 Once the control gains in the three directions of the roof and body are determined, the damping force control device 350 can control the vehicle's three-direction velocities v as shown in Formula 1 below. heave w pitch and w roll Multiplied by the control gain C in three directions of the vehicle body sky_heave C sky_pitch and C sky_ro11 This determines the required damping force F for the vehicle body. sky_heave , M sky_pitch and M sky_ro11 .

[0057] [Formula 1]

[0058] F sky_heave =C sky_heave ·v heave

[0059] Msky_pitch =C sky_pitch ·w pitch

[0060] M sky_roll =C sky_roll ·w roll

[0061] Once the required damping force for the vehicle body is determined, the damping force control device 350 can use vehicle specification information and the sensor mounting locations at each vehicle body corner to allocate the required damping force F for each corner. corner (or F) sky_comer The required damping force F at each corner is used to achieve the damping force required for the roof body. comer It can be expressed as the following formula 2.

[0062] [Formula 2]

[0063] F corner =H T ·F modal

[0064] in, “F fl "This is the damping force required for the left front corner," F fr "This is the damping force required for the right front corner," F rl "This is the damping force required at the left rear corner," F rr "F" is the damping force required for the right rear corner. heave "M" is the damping force required in the vertical direction. roll "M" is the moment in the tilt direction. pitch "M" is the torque in the pitch direction, and "M" is the torque in the pitch direction. warp " is the virtual torque (M)" warp =ε×M roll Typically, "ε" can be set to "0" (zero). "t" f "It is the left and right distance from the center of the front axle to the location where the vehicle body angle acceleration sensor (the first acceleration sensor) is installed," t r "a" is the left-right distance from the center of the rear axle to the location where the vehicle body angle acceleration sensor (first acceleration sensor) is installed; "a" is the front-rear distance from the center of gravity to the location where the front wheel side vehicle body angle acceleration sensor (first acceleration sensor) is installed; and "b" is the front-rear distance from the center of gravity to the location where the rear wheel side vehicle body angle acceleration sensor (first acceleration sensor) is installed.

[0065] Next, the damping force control device 350 can determine the final required damping force for each wheel. This can be based on... Figure 3 The 1 / 4 scale vehicle model shown is used to determine the final required damping force for each wheel. Figure 3 In the middle, Ks and K t These are the suspension spring rate and the tire spring rate, m s and m us It refers to the vehicle body mass and wheel mass, and v s v us and v i It consists of the vehicle's vertical velocity at each corner, the vertical velocity of each wheel, and the road condition input for each wheel (road velocity for each wheel), as well as C. sky C ground and C passive These are the ceiling control gain, virtual tire damping control gain, and passive damping control gain.

[0066] When the required damping force for virtual tire damping is determined based on the required damping force of each wheel's canopy, the vertical speed of each wheel, and the road speed of each wheel, the damping force control device 350 can perform semi-active control. In semi-active control, the required damping force is activated (ON) when a preset specific condition for each control logic is met, and the required damping force is disabled (OFF) when the preset specific condition is not met, thus performing target control.

[0067] Referring to Table 1, when based on the vertical velocity v of the vehicle body angle... s and the vertical velocity v of each wheel us Under certain conditions, the canopy control logic can activate the required damping force for each wheel, while deactivating it when those conditions are not met. Furthermore, the virtual tire damping control logic can be based on the vehicle's angular vertical velocity v at each angle. s The vertical velocity v of each wheel us And the road surface condition input (road speed of each wheel) v i This determines whether specific conditions are met. The virtual tire damping control logic can activate the required damping force for each wheel's virtual tire damping when the preset specific conditions are met, and deactivate the required damping force for each wheel's virtual tire damping when the preset specific conditions are not met. Conversely, the passive damping control logic can always be operated and can be based on the passive damping control gain C. passive Vertical velocity v of the car body at each angle s And the vertical velocity v of each wheel us To determine the passive damping force.

[0068] Table 1

[0069]

[0070] In the current situation, the virtual tire damping control gain C can be determined based on vehicle driving information. ground and passive damping control gain Cpassive .

[0071] Damping force control device 350 can control the required damping force F of the ceiling. sky_final The damping force F required for virtual tire damping ground and the required damping force F pass The final required damping force for each corner (wheel) is determined by summing the results. In other words, the final required damping force for each corner can be expressed as Equation 3 below.

[0072] [Formula 3]

[0073] F final =F sky_final +F ground +F passive

[0074] Figure 4 This is a flowchart illustrating a method for controlling a vehicle suspension according to an exemplary embodiment of the present invention.

[0075] In S110, the controller 300 acquires the vehicle's vertical acceleration at each corner, the wheel's vertical acceleration, and vehicle driving information. In S111, the controller 300 acquires the vehicle's vertical acceleration at each corner via the first acceleration sensor 110, and acquires the vertical acceleration of each wheel via the second acceleration sensor 120. The vehicle's vertical acceleration at each corner (vehicle angle vertical acceleration) and the vertical acceleration of each wheel (wheel vertical acceleration) can be directly used for damping force control. The controller 300 acquires vehicle driving information via CAN communication. The vehicle driving information can be used to determine each control logic and the damping force gain for vehicle motion control in each direction.

[0076] In S120, the controller 300 can perform post-processing on the vehicle body angular vertical acceleration and the wheel vertical acceleration. The controller 300 can perform filtering to remove noise included in the signals received from the first acceleration sensor 110 and the second acceleration sensor 120. The controller 300 can determine the vehicle body vertical velocity at each angle, the vertical velocity of each wheel, the vehicle body displacement information at each angle, and the displacement information of each wheel by integration.

[0077] In S130, the controller 300 can estimate road roughness in real time using vehicle body angular vertical acceleration, wheel vertical acceleration, and post-processed signals (e.g., vehicle body angular vertical velocity and wheel vertical velocity). The controller 300 can also estimate road roughness using a Kalman filter and / or simplified vehicle model information.

[0078] In S140, the controller 300 can determine the appropriate roof control gain and virtual tire damping control gain by determining driving conditions such as turning, deceleration, or acceleration, and the road roughness state, based on vehicle driving information and road surface roughness information. The controller 300 can also determine the passive damping control gain (passive damping force) based on vehicle driving information.

[0079] In S150, the controller 300 determines the required damping force for the roof at each vehicle body angle based on the post-processed signal and the roof control gain. Specifically, in S151, the controller 300 can determine the vehicle center of gravity movement (velocities in three directions of the vehicle center of gravity) using the vertical velocity of the vehicle body angle and vehicle specification information. Vehicle specification information may include wheelbase, track width, distance between the front wheels and the vehicle center of gravity (vehicle center of gravity), distance between the rear wheels and the vehicle center of gravity, etc. The controller 300 can determine the vertical velocity, pitch rate, and roll rate of the vehicle's center of gravity based on the vertical velocity of the vehicle body at each angle and the vehicle specification information. In S153, the controller 300 can determine the force and torque required for roof control based on the three-directional velocities of the vehicle center of gravity determined in S151 and the roof control gain determined in S140. The controller 300 can determine the required damping force for the roof proportionally to the vertical velocity, pitch rate, and roll rate of the vehicle center of gravity determined in S151 and the roof control gain determined in S140. In S155, the controller 300 can use the conversion formula used in S151 to allocate the required damping force to each corner of the vehicle for the force and torque required to satisfy the attenuation of the vehicle's center of gravity in three directions. The controller 300 can allocate the required damping force (damping force) of the vehicle body to each corner based on the determined force and torque required for slack control.

[0080] In S160, the controller 300 can determine the required damping force for virtual tire damping of each wheel by using the road surface roughness estimated in S130 and the virtual tire damping control gain determined in S140. The required damping force can be determined proportionally to the relative speed between the wheel and the road surface input.

[0081] In S170, the controller 300 can determine the final required damping force for each vehicle body corner by integrating the required roof damping force (damping force), the required damping force for virtual tire damping, and the required passive damping force determined in S140. The controller 300 can determine the passive damping force based on the passive damping control gain determined in S140, the vehicle body vertical speed, and the wheel vertical speed.

[0082] In S180, the controller 300 can generate the actual current signal applied to the variable damper 200 based on the final required damping force at each corner and the characteristics of the damper. The controller 300 can determine the amount of current to be applied to the solenoid valve of the variable damper 200, taking into account the final required damping force at each corner and the characteristics of the variable damper 200. The controller 300 can generate a current signal based on the determined current amount and apply that current signal to the solenoid valve. Furthermore, the controller 300 can limit the upper and lower limits of the current signal by considering the actuator (e.g., solenoid valve) load and minimum drive current.

[0083] According to the above implementation method, tire road grip performance (minimizing tire vertical force fluctuations) can be improved by implementing control that minimizes the relative speed between the wheel and the road surface. With improved tire road grip, handling performance can be improved, and ride comfort can be enhanced through roof control.

[0084] Figure 5 This is a block diagram illustrating a computational system for performing a method of controlling a vehicle suspension according to various exemplary embodiments of the present invention.

[0085] Reference Figure 5 The computing system 1000 may include at least one processor 1100, memory 1300, user interface input device 1400, user interface output device 1500, memory 1600, and network interface 1700 connected via system bus 1200.

[0086] Processor 1100 may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in memory 1300 and / or memory 1600. Memory 1300 and memory 1600 may include various types of volatile or non-volatile storage media. For example, memory 1300 may include read-only memory (ROM) 1310 and random access memory (RAM) 1320.

[0087] Therefore, the processing of the methods or algorithms described with respect to embodiments of the present invention can be directly implemented by hardware, software modules, or a combination thereof executed by processor 1100. The software modules can reside in storage media (i.e., memory 1300 and / or memory 1600), such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, solid-state drives (SSDs), removable disks, or CD-ROMs. An exemplary storage medium is coupled to processor 1100, and processor 1100 can read information from and write information to the storage medium. In another approach, the storage medium can be integrated with processor 1100. The processor and storage medium can reside in an application-specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In yet another approach, processor 1100 and storage medium can reside as separate components in a user terminal.

[0088] According to various exemplary embodiments of the present invention, because the variable damper is controlled in consideration of virtual tire damping, the relative speed between the wheel and the road surface can be minimized, thereby improving the tire's road grip (minimizing the undulating force in the vertical direction of the tire).

[0089] According to various exemplary embodiments of the present invention, when turning, the vehicle yaw rate gain (related to responsiveness) increases, but the vehicle sideslip angle (related to stability) decreases, thereby reducing transient lateral acceleration and yaw rate overshoot ratio (stability and grip performance).

[0090] For ease of interpretation and accurate definition of the appended claims, the terms “above,” “below,” “inside,” “outside,” “up,” “down,” “facing upward,” “facing downward,” “front,” “back,” “rear,” “inner,” “external,” “inward,” “outer,” “inner,” “outer,” “forward,” and “backward” are used to describe features of the exemplary embodiments as shown in the accompanying drawings. It will also be understood that the term “connection” or its derivatives refer to both direct and indirect connections.

[0091] For purposes of illustration and description, the foregoing description of specific exemplary embodiments of the invention has been given. These are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it will be apparent that many modifications and variations are possible in accordance with the foregoing teachings. The exemplary embodiments were chosen and described to explain certain principles of the invention and its practical application, enabling others skilled in the art to make and utilize various exemplary embodiments of the invention and their various alternatives and modifications. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. An apparatus for controlling a suspension of a vehicle, the apparatus comprising: a variable damper installed between a body of the vehicle and a wheel of the vehicle; a first acceleration sensor installed on each corner of the body and configured to measure a body corner vertical acceleration; a second acceleration sensor installed on each wheel of the vehicle and configured to measure a wheel vertical acceleration; and a controller coupled to the first acceleration sensor and the second acceleration sensor, and configured to estimate a road roughness from the body corner vertical acceleration and the wheel vertical acceleration, determine a virtual tire damping required damping force from the estimated road roughness, and adjust a damping force of the variable damper from the determined virtual tire damping required damping force, wherein the controller is configured to determine a vertical velocity, a pitch angular velocity, and a roll angular velocity of a body center of gravity from a body corner vertical velocity and a wheel vertical velocity, determine a skyhook control required force and moment from the vertical velocity, the pitch angular velocity, and the roll angular velocity of the body center of gravity and a skyhook control gain, and distribute a required damping force of each body corner from the skyhook control required force and moment, and wherein the controller is configured to determine a final required damping force of each corner by integrating the required damping force of each body corner, the virtual tire damping required damping force, and a passive required damping force. the controller is configured to remove noise in a measurement signal output from the first acceleration sensor and the second acceleration sensor by filtering out the noise in the measurement signal, and acquire the body corner vertical velocity and the wheel vertical velocity by integration.

2. The apparatus of claim 1, wherein, the controller is configured to estimate the road roughness by using a Kalman filter.

3. The apparatus of claim 1, wherein, the controller is configured to determine the skyhook control gain, a virtual tire damping control gain, and the passive required damping force from the road roughness and vehicle driving information acquired through a controller area network.

4. The apparatus of claim 2, wherein, the controller is configured to determine the virtual tire damping required damping force by using the road roughness and the virtual tire damping control gain.

5. The apparatus of claim 4, wherein, the controller is configured to determine a current to be applied to the variable damper from the final required damping force of each corner.

6. The apparatus of claim 5, wherein, the controller is configured to control the damping force of the variable damper by adjusting a current signal applied to a solenoid valve of the variable damper.

7. The apparatus of claim 1, wherein, 8.A method for controlling a suspension of a vehicle, the method comprising the steps of: measuring a body corner vertical acceleration and a wheel vertical acceleration by first and second acceleration sensors installed on a body and a wheel of the vehicle, respectively; estimating a road roughness from the body corner vertical acceleration and the wheel vertical acceleration by a controller; determining a virtual tire damping required damping force from the road roughness by the controller; adjusting a damping force of a variable damper from the virtual tire damping required damping force by the controller; and ​ determining, by the controller, a vertical velocity, a pitch angular velocity, and a roll angular velocity of a vehicle body center of gravity from the vehicle body angular vertical velocities and the wheel vertical velocities; determining, by the controller, a skyhook control required force and moment from the vertical velocity, the pitch angular velocity, and the roll angular velocity of the vehicle body center of gravity and a skyhook control gain; and distributing, by the controller, a required damping force for each of the vehicle body angles from the skyhook control required force and moment, wherein adjusting the damping force of the variable damper includes: determining a final required damping force for each of the angles by integrating the required damping force for each of the vehicle body angles, the virtual tire damping required damping force, and a passive required damping force.

9. The method of claim 8, wherein, measuring the vehicle body angular vertical accelerations and the wheel vertical accelerations includes: obtaining the vehicle body angular vertical velocities and the wheel vertical velocities by filtering out noise in the measurement signals and by integrating the measurement signals output from the first and second acceleration sensors.

10. The method of claim 9, wherein, estimating the road roughness includes: obtaining vehicle driving information through a controller area network; and determining the skyhook control gain, a virtual tire damping control gain, and the passive required damping force from the vehicle driving information and the road roughness.

11. The method of claim 10, wherein, determining the virtual tire damping required damping force includes: determining the virtual tire damping required damping force by using the road roughness and the virtual tire damping control gain.

12. The method of claim 11, wherein, adjusting the damping force of the variable damper includes: determining a current to be applied to the variable damper from the final required damping force for each of the angles.

13. The method of claim 8, wherein, adjusting the damping force of the variable damper further includes: controlling the damping force of the variable damper by adjusting a current signal applied to a solenoid valve of the variable damper.

14. The method of claim 8, wherein, the controller includes: a processor; and a non-transitory storage medium having recorded thereon a program for executing the method of claim 10 and executed by the processor.

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