Vehicle vibration control method and vibration control system

Abstract

When performing vibration damping control using a control map that represents the correspondence between position and parameters related to the vertical movement of each wheel of the vehicle, the left and right wheels in opposite phase inputs and left and right wheels in the same phase inputs are appropriately reflected in this vibration damping control. [Solution] Vibration damping control processing is performed using a parameter map based on time-series data in which frequency components higher than the first frequency remain in the parameters related to the vertical movement of each wheel. In the vibration damping control processing, parameters related to the vertical movement of these wheels at the predicted passing position of each wheel are read from the parameter map, and the in-phase inputs of the left and right wheels of the first and second wheels, and the out-of-phase inputs of the left and right wheels of the first and second wheels are calculated. Then, based on the out-of-phase inputs of the left and right wheels and the out-of-phase inputs of the left and right wheels, the control amounts of the actuators that control the suspension stroke of the first and second wheels are calculated.

Description

Technical Field

[0001] The present disclosure relates to a technique for performing vibration control of a vehicle using a control map.

Background Art

[0002] Patent Document 1 discloses a road surface displacement map representing the correspondence between road surface displacement (road surface unevenness) and position. By using such a road surface displacement map, vibration control is performed. Specifically, the road surface displacement at a predetermined position in front of the vehicle is recognized in advance from the road surface displacement map. The control amount of the active suspension is calculated in advance according to the recognized road surface displacement in advance. Then, by controlling the active suspension at the timing when the wheel passes through the predetermined position, the vibration of the vehicle is effectively suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, when creating the road surface displacement map, filtering processing is performed to cut off frequencies significantly lower than the vehicle body frequency and frequencies significantly higher than the vehicle body frequency from the road surface state data. Here, the road surface state data can be said to be data of parameters related to the road surface displacement. Also, the data of parameters related to the road surface displacement can be said to be data of parameters related to the vertical movement of the wheel in contact with the road surface.

[0005] This disclosure considers vibration damping control using a control map that represents the correspondence between position and parameters related to the vertical motion of each wheel of a vehicle. Such a control map can be created, for example, using time-series data of parameters related to the vertical motion of each wheel. However, the parameters related to the vertical motion of each wheel include extremely low-frequency components originating from altitude changes, etc. Therefore, when creating the control map, it is desirable to perform filtering using a high-pass filter to cut out the extremely low-frequency components from the parameters related to the vertical motion of each wheel. However, if an excessively strong high-pass filter is used, the out-of-phase inputs of the left and right wheels, which originate from the different vertical displacements of the left and right wheels, will also be cut out.

[0006] When vibration damping control is performed using a control map created from time-series data from which the left and right wheel inverse phase inputs have been cut, these left and right wheel inverse phase inputs are not reflected in the vibration damping control, resulting in a decrease in the control effect. This problem can be solved by using a weak high-pass filter in the filtering process. However, in this case, the left and right wheel in-phase inputs, which originate from the same vertical displacement of the left and right wheels that are susceptible to changes in altitude, remain. Consequently, in vibration damping control using a control map, an excessive amount of control to try to cancel out the left and right wheel in-phase inputs may reduce the control effect.

[0007] One objective of this disclosure is to provide a technology that can appropriately reflect left and right wheel out-of-phase inputs and left and right wheel in-phase inputs in vibration damping control when performing vibration damping control using a control map that represents the correspondence between position and parameters related to the vertical movement of each wheel of a vehicle. [Means for solving the problem]

[0008] The first aspect of this disclosure is a method for performing vibration control of a vehicle using a control map, which is performed by a computer, and has the following features: The control map includes a parameter map that shows the correspondence between position and parameters related to the vertical movement of each wheel of the vehicle. The parameter map is created or updated by filtering time-series data of parameters related to the vertical movement of each wheel of the vehicle. The filtering process includes filtering using a first high-pass filter that cuts out frequency components below a first frequency from the parameters related to the vertical movement of each wheel of the vehicle. The method involves calculating the predicted passing positions of each wheel of the vehicle from the current time to a preview time while the vehicle is in motion, obtaining parameters related to the vertical movement of each wheel at the predicted passing position from the parameter map, and calculating the left and right wheel in-phase inputs derived from the same vertical displacement of the first and second wheels based on the parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel of the vehicle and the parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel of the vehicle, which constitutes the left and right wheels together with the first wheel. This includes calculating left and right wheel out-of-phase inputs resulting from different vertical displacements of the first and second wheels, based on parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel and parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel, and calculating each control amount of the actuators that control the suspension stroke of the first and second wheels, based on the left and right wheel out-of-phase inputs of the first and second wheels and the left and right wheel in-phase inputs of the first and second wheels.

[0009] The second aspect of this disclosure is a system for performing vibration control of a vehicle using a control map, and has the following features. The system comprises an actuator that controls the suspension stroke of each wheel of the vehicle, one or more storage devices that store the control map, and one or more processors that perform vibration damping control processing of the vehicle by controlling the actuators based on the control map. The control map includes a parameter map that shows the correspondence between position and parameters related to the vertical movement of each wheel of the vehicle. The parameter map is created or updated by filtering time-series data of parameters related to the vertical movement of each wheel of the vehicle. The filtering process includes filtering to remove frequency components below a first frequency from the parameters related to the vertical movement of each wheel of the vehicle. The vibration damping control process includes: calculating the predicted passing position of each wheel of the vehicle from the current time to a preview time after the vehicle is in motion; obtaining parameters related to the vertical movement of each wheel of the vehicle at the predicted passing position from the parameter map; calculating a left and right wheel in-phase input originating from the same vertical displacement of the first and second wheels based on parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel of the vehicle and parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel of the vehicle which constitutes the left and right wheels with the first wheel; calculating a left and right wheel out-of-phase input originating from different vertical displacements of the first and second wheels based on parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel and parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel; and calculating each control amount of the actuator that controls the suspension stroke of the first and second wheels based on the left and right wheel out-of-phase input of the first and second wheels and the left and right wheel in-phase input of the first and second wheels. [Effects of the Invention]

[0010] According to this disclosure, vibration damping control processing is performed using a parameter map created or updated based on time-series data in which frequency components higher than a first frequency remain in the parameters related to the vertical motion of each wheel of the vehicle. In the vibration damping control processing, parameters related to the vertical motion of each wheel at the predicted passing position of each wheel are read from the parameter map, and the in-phase inputs of the left and right wheels of the first and second wheels, and the out-of-phase inputs of the left and right wheels of the first and second wheels are calculated. Then, based on the out-of-phase inputs of the left and right wheels of the first and second wheels, and the out-of-phase inputs of the left and right wheels of the first and second wheels, the control amounts of the actuators that control the suspension stroke of the first and second wheels are calculated. Therefore, it is possible to appropriately reflect the in-phase inputs and out-of-phase inputs of the left and right wheels in the vibration damping control. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing an example of the vehicle configuration according to the embodiment. [Figure 2] This is a conceptual diagram showing an example of the suspension configuration according to the embodiment. [Figure 3] This is a flowchart showing an example of the process for calculating unsprung displacement. [Figure 4] This is a block diagram showing an example configuration of a vehicle control system according to an embodiment. [Figure 5] This block diagram shows an example of driving environment information according to the embodiment. [Figure 6] This block diagram shows an example configuration of a map management system according to an embodiment. [Figure 7] This is a conceptual diagram illustrating the unsprung displacement map according to the embodiment. [Figure 8] This is a flowchart showing the map generation / update process according to the embodiment. [Figure 9] This is a conceptual diagram illustrating the preview control using the unsprung displacement map according to the embodiment. [Figure 10] This is a flowchart illustrating the preview control using the unsprung displacement map according to the embodiment.

Best Mode for Carrying Out the Invention

[0012] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0013] 1. Suspension and Vertical Movement Parameters FIG. 1 is a schematic diagram showing a configuration example of a vehicle 1 according to an embodiment. The vehicle 1 includes wheels 2 and a suspension 3. The wheels 2 include a left front wheel 2FL, a right front wheel 2FR, a left rear wheel 2RL, and a right rear wheel 2RR. The left front wheel 2FL and the right front wheel 2FR constitute left and right wheels on the front wheel axle side, and the left rear wheel 2RL and the right rear wheel 2RR constitute left and right wheels on the rear wheel axle side. Suspensions 3FL, 3FR, 3RL, and 3RR are provided for the left front wheel 2FL, the right front wheel 2FR, the left rear wheel 2RL, and the right rear wheel 2RR, respectively. In the following description, each wheel will be referred to as wheel 2 and each suspension will be referred to as suspension 3 when there is no particular need for distinction.

[0014] FIG. 2 is a conceptual diagram showing a configuration example of the suspension 3. The suspension 3 is provided so as to connect between a subframe structure 4 and a superframe structure 5 of the vehicle 1. The subframe structure 4 includes the wheel 2. The suspension 3 includes a spring 3S, a damper (shock absorber) 3D, and an actuator 3A. The spring 3S, the damper 3D, and the actuator 3A are provided in parallel between the subframe structure 4 and the superframe structure 5. The spring constant of the spring 3S is K. The damping coefficient of the damper 3D is C. The damping force of the damper 3D may be variable. The actuator 3A applies a vertical control force Fc between the subframe structure 4 and the superframe structure 5.

[0015] Here, the definitions of terms are given. "Road surface displacement Zr" is the vertical displacement of the road surface RS. "Displacement Zu under the spring" is the vertical displacement of the structure 4 under the spring. "Displacement Zs above the spring" is the vertical displacement of the structure 5 above the spring. "Velocity Zu' under the spring" is the vertical velocity of the structure 4 under the spring. "Velocity Zs' above the spring" is the vertical velocity of the structure 5 above the spring. "Acceleration Zu'' under the spring" is the vertical acceleration of the structure 4 under the spring. "Acceleration Zs'' above the spring" is the vertical acceleration of the structure 5 above the spring. Note that the signs of each parameter are positive when upward and negative when downward.

[0016] The wheel 2 moves on the road surface RS. In the following description, the parameters related to the vertical motion of the wheel 2 are referred to as "vertical motion parameters". Examples of vertical motion parameters include the above-mentioned road surface displacement Zr, displacement Zu under the spring, velocity Zu' under the spring, acceleration Zu'' under the spring, displacement Zs above the spring, velocity Zs' above the spring, acceleration Zs'' above the spring, etc. It can also be said that the vertical motion parameters are "road surface displacement parameters" related to the road surface displacement Zr.

[0017] As an example, in the following description, the case where the road surface displacement-related value is the displacement Zu under the spring is considered. When generalizing, the "displacement Zu under the spring" in the following description shall be read as the "road surface displacement-related value".

[0018] Figure 3 is a flowchart showing an example of the displacement Zu under the spring calculation process.

[0019] In step S11, the acceleration Zs'' above the spring is detected by the acceleration sensor 22 above the spring installed on the structure 5 above the spring. In step S12, the displacement Zs above the spring is calculated by double-integrating the acceleration Zs'' above the spring.

[0020] In step S13, the stroke ST (=Zs-Zu), which is the relative displacement between the sprung mass structure 5 and the unsprung mass structure 4, is obtained. For example, the stroke ST is detected by a stroke sensor installed on the suspension 3. As another example, the stroke ST may be estimated based on the sprung mass acceleration Zs'' by an observer configured based on a single-wheel two-degree-of-freedom model.

[0021] In step S14, the difference between the sprung displacement Zs and the stroke ST is calculated as the unsprung displacement Zu.

[0022] As another example, the unsprung acceleration Zu'' may be detected by an unsprung acceleration sensor, and the unsprung displacement Zu may be calculated from the unsprung acceleration Zu''.

[0023] In step S15, filtering is performed on the time-series data of the unsprung displacement Zu. The unsprung displacement Zu includes extremely low-frequency components (e.g., components below 0.5 Hz) originating from altitude changes, etc. However, these extremely low-frequency components also include the out-of-phase inputs of the left and right wheels. Therefore, in step S15, filtering is performed using a first high-pass filter to cut out components below a first frequency (e.g., 0.2 Hz) and leave the frequency components including the out-of-phase inputs of the left and right wheels. In this case, extremely low-frequency components originating from altitude changes, etc., will also remain, but the decision to cut these extremely low-frequency components will be made in the vibration damping control process described later.

[0024] 2. Vehicle control system 2-1. Example Configuration Figure 4 is a block diagram showing an example configuration of a vehicle control system 10 according to an embodiment. The vehicle control system 10 is mounted on a vehicle 1 and controls the vehicle 1. The vehicle control system 10 includes a vehicle state sensor 20, a recognition sensor 30, a position sensor 40, a communication device 50, a driving device 60, and a control device 70.

[0025] The vehicle state sensor 20 detects the state of vehicle 1. The vehicle state sensor 20 includes a vehicle speed sensor (wheel speed sensor) 21 for detecting the vehicle speed V of vehicle 1, a sprung mass acceleration sensor 22 for detecting the sprung mass acceleration Zs'', etc. The vehicle state sensor 20 may also include a stroke sensor 23 for detecting the stroke ST. The vehicle state sensor 20 may also include an unsprung mass acceleration sensor. In addition, the vehicle state sensor 20 may include a lateral acceleration sensor, a yaw rate sensor, a steering angle sensor, etc.

[0026] The recognition sensor 30 recognizes (detects) the surrounding environment of the vehicle 1. Examples of recognition sensors include cameras, LIDAR (Laser Imaging Detection and Ranging), radar, etc.

[0027] The position sensor 40 detects the position and orientation of vehicle 1. For example, the position sensor 40 includes a GNSS (Global Navigation Satellite System).

[0028] The communication device 50 communicates with the outside of the vehicle 1.

[0029] The running gear 60 includes a steering gear 61, a drive gear 62, a braking gear 63, and a suspension 3 (see Figure 2). The steering gear 61 steers the wheels 2. For example, the steering gear 61 includes an electric power steering (EPS) system. The drive gear 62 is a power source that generates driving force. Examples of the drive gear 62 include an engine, an electric motor, an in-wheel motor, etc. The braking gear 63 generates braking force.

[0030] The control device 70 is a computer that controls the vehicle 1. The control device 70 includes one or more processors 71 (hereinafter simply referred to as processor 71) and one or more storage devices 72 (hereinafter simply referred to as storage devices 72). The processor 71 performs various processes. For example, the processor 71 includes a CPU (Central Processing Unit). The storage devices 72 store various information necessary for processing by the processor 71. Examples of storage devices 72 include volatile memory, non-volatile memory, HDD (Hard Disk Drive), SSD (Solid State Drive), etc. The control device 70 may also include one or more ECUs (Electronic Control Units).

[0031] The vehicle control program 80 is a computer program for controlling vehicle 1 and is executed by the processor 71. The vehicle control program 80 is stored in the storage device 72. Alternatively, the vehicle control program 80 may be recorded on a computer-readable recording medium. The processor 71 executes the vehicle control program 80, thereby realizing the functions of the control device 70.

[0032] 2-2. Driving Environment Information Figure 5 is a block diagram showing an example of driving environment information 90 indicating the driving environment of vehicle 1. The driving environment information 90 is stored in the storage device 72. The driving environment information 90 includes map information 91, vehicle status information 92, surrounding conditions information 93, and location information 94.

[0033] Map information 91 includes a general navigation map. Map information 91 may show lane layouts, road shapes, etc. Map information 91 may also include location information such as white lines, traffic lights, signs, and landmarks. Map information 91 is obtained from a map database. The map database may be installed in the vehicle 1 or stored on an external management server. In the latter case, the control device 70 communicates with the management server to obtain the necessary map information 91.

[0034] Map information 91 further includes the "unsprung displacement map 200". Details of the unsprung displacement map 200 will be described later.

[0035] Vehicle status information 92 is information indicating the state of vehicle 1. The control device 70 acquires vehicle status information 92 from the vehicle status sensor 20. For example, vehicle status information 92 includes vehicle speed V, sprung mass acceleration Zs'', stroke ST, lateral acceleration, yaw rate, steering angle, etc. Vehicle speed V may be calculated from the vehicle position detected by the position sensor 40. The control device 70 may also calculate the unsprung mass displacement Zu using the method shown in Figure 3. In that case, vehicle status information 92 also includes the unsprung mass displacement Zu calculated by the control device 70.

[0036] The surrounding situation information 93 is information that indicates the conditions around the vehicle 1. The control device 70 recognizes the conditions around the vehicle 1 using the recognition sensor 30 and acquires the surrounding situation information 93. For example, the surrounding situation information 93 includes image information captured by a camera. As another example, the surrounding situation information 93 includes point cloud information obtained by a LIDAR.

[0037] The surrounding environment information 93 further includes "object information" concerning objects around vehicle 1. Examples of objects include pedestrians, bicycles, other vehicles (preceding vehicles, parked vehicles, etc.), road configurations (white lines, curbs, guardrails, walls, median strips, roadside structures, etc.), signs, poles, obstacles, etc. The object information indicates the relative position and relative velocity of the object with respect to vehicle 1. For example, by analyzing image information obtained by a camera, an object can be identified and its relative position can be calculated. Alternatively, an object can be identified and its relative position and relative velocity can be obtained based on point cloud information obtained by LIDAR.

[0038] The location information 94 is information indicating the position and orientation of vehicle 1. The control device 70 acquires the location information 94 from the detection results of the position sensor 40. Alternatively, the control device 70 may acquire highly accurate location information 94 by using a well-known self-position estimation process (localization) that utilizes object information and map information 91.

[0039] 2-3. Vehicle Control The control device 70 performs vehicle driving control to control the movement of the vehicle 1. Vehicle driving control includes steering control, drive control, and braking control. The control device 70 performs vehicle driving control by controlling the driving devices 60 (steering device 61, drive device 62, and braking device 63). The control device 70 may also perform driving assistance control to assist the driving of the vehicle 1 based on driving environment information 90. Examples of driving assistance control include lane keeping control, collision avoidance control, and automatic driving control.

[0040] Furthermore, the control device 70 controls the suspension 3. Typically, the control device 70 controls the suspension 3 to perform vibration damping control to suppress vibrations of the vehicle 1. For example, the control device 70 controls the actuator 3A to generate a vertical control force Fc between the unsprung mass structure 4 and the sprung mass structure 5 (see Figure 2). In another example, the control device 70 may variably control the damping force of the damper 3D. The vibration damping control includes "preview control," which will be described later.

[0041] 3. Map Management System 3-1. Example Configuration Figure 6 is a block diagram showing an example configuration of a map management system 100 according to an embodiment. The map management system 100 is a computer that manages various types of map information. The management of map information includes the generation, updating, provision, and distribution of map information. Typically, the map management system 100 is a management server on the cloud. The map management system 100 may also be a distributed system in which multiple servers perform distributed processing.

[0042] The map management system 100 includes a communication device 110. The communication device 110 is connected to a communication network NET. For example, the communication device 110 communicates with a number of vehicles 1 via the communication network NET.

[0043] The map management system 100 further includes one or more processors 120 (hereinafter simply referred to as processor 120) and one or more storage devices 130 (hereinafter simply referred to as storage devices 130). The processor 120 performs various information processing. For example, the processor 120 includes a CPU. The storage devices 130 store various map information. The storage devices 130 also store various information necessary for processing by the processor 120. Examples of storage devices 130 include volatile memory, non-volatile memory, HDD, SSD, etc.

[0044] The map management program 140 is a computer program for map management and is executed by the processor 120. The map management program 140 is stored in the storage device 130. Alternatively, the map management program 140 may be recorded on a computer-readable recording medium. The execution of the map management program 140 by the processor 120 realizes the functions of the map management system 100.

[0045] The processor 120 communicates with the vehicle control system 10 of the vehicle 1 via the communication device 110. The processor 120 collects various information from the vehicle control system 10 and generates and updates map information based on the collected information. The processor 120 also distributes the map information to the vehicle control system 10. Furthermore, the processor 120 provides map information in response to requests from the vehicle control system 10.

[0046] 3-2. Unsprung Displacement Map One of the map information managed by the map management system 100 is the "unsprung displacement map (vertical motion parameter map) 200". The unsprung displacement map 200 is a map relating to the unsprung displacement Zu (vertical motion parameter). The unsprung displacement map 200 is stored in the memory device 130.

[0047] Figure 7 is a conceptual diagram illustrating the unsprung displacement map 200. The absolute coordinate system in the horizontal plane is defined, for example, by the latitude and longitude directions. The position in the horizontal plane is defined, for example, by latitude LAT and longitude LON. The unsprung displacement map 200 represents the correspondence between position (LAT, LON) and unsprung displacement Zu. In other words, the unsprung displacement map 200 expresses the unsprung displacement Zu as a function of position (LAT, LON).

[0048] The road area is divided into a mesh-like structure on a horizontal plane, for example. In other words, the road area is divided into multiple unit areas M on a horizontal plane. A unit area M is, for example, a square. The length of one side of the square is, for example, 10 cm. The unsprung displacement map 200 represents the correspondence between the position of a unit area M and the unsprung displacement Zu. The position of a unit area M may be defined by a representative position of that unit area M (e.g., the center position), or by the range of that unit area M (latitude range, longitude range). The unsprung displacement Zu of a unit area M is, for example, the average value of the unsprung displacement Zu obtained within that unit area M. The smaller the unit area M, the higher the resolution of the unsprung displacement map 200.

[0049] Even when wheel 2 passes through the same location (LAT, LON) on the road, the calculated unsprung displacement Zu may differ depending on the direction of travel of vehicle 1. For example, consider the case where there are ruts on the road. The unsprung displacement Zu may differ depending on whether wheel 2 moves along the rut or crosses the rut. Therefore, the direction of travel φ of vehicle 1 may be obtained from position information 94, and the unsprung displacement map 200 may be created and updated separately for each direction of travel φ.

[0050] 3-3. Map generation / update process The processor 120 collects information from multiple vehicles 1 via the communication device 110. Based on the information collected from the multiple vehicles 1, the processor 120 generates and updates the unsprung displacement map 200. An example of the map generation / update process will be described in more detail below.

[0051] The position in the unsprung displacement map 200 represents the position that wheel 2 has passed through. The position of each wheel 2 is calculated based on the position information 94 described above. Specifically, the relative positional relationship between the reference point of the vehicle position on vehicle 1 and each wheel 2 is known information. Based on this relative positional relationship and the vehicle position indicated by the position information 94, the position of each wheel 2 can be calculated.

[0052] The unsprung displacement Zu is calculated using the method shown in Figure 3. Specifically, the sprung displacement Zs and stroke ST are obtained using the vehicle state sensor 20 mounted on the vehicle 1. For convenience, these sprung displacement Zs and stroke ST are referred to as "sensor-based information." The unsprung displacement Zu is calculated based on this sensor-based information.

[0053] For example, the control device 70 of the vehicle control system 10 associates the position of wheel 2 at the same time with sensor-based information. The control device 70 then transmits a set of time-series data of the position of wheel 2 and time-series data of sensor-based information to the map management system 100. The processor 120 of the map management system 100 calculates the unsprung displacement Zu based on the received sensor-based information. Furthermore, the processor 120 generates and updates the unsprung displacement map 200 based on the time-series data of the position of wheel 2 and the time-series data of the unsprung displacement Zu.

[0054] Furthermore, when calculating the unsprung displacement Zu in the map management system 100, there are no processing time constraints, so filtering can be performed using a zero-phase filter. By using a zero-phase filter, "phase shift" can be prevented.

[0055] Figure 8 is a flowchart that summarizes the map generation / update process according to the embodiment.

[0056] In step S21, the processor 120 of the map management system 100 acquires "map update information" from the vehicle 1 (vehicle control system 10) via the communication device 110. The map update information includes time-series data of the position (wheel position) of the vehicle 1. The map update information also includes time-series data of sensor-based information (e.g., sprung displacement Zs and stroke ST) necessary for calculating the unsprung displacement Zu. Alternatively, the map update information may include time-series data of the unsprung displacement Zu calculated by the control device 70 of the vehicle control system 10.

[0057] In step S22, the processor 120 of the map management system 100 generates / updates the unsprung displacement map 200 based on the map update information.

[0058] 3-4. Variations The vehicle control system 10 of vehicle 1 may maintain a database of unsprung displacement maps 200 and generate / update its own unsprung displacement maps 200. In other words, the map management system 100 may be included in the vehicle control system 10.

[0059] 4. Vibration control processing using unsprung displacement map The control device 70 of the vehicle control system 10 communicates with the map management system 100 via the communication device 50. The control device 70 obtains an unsprung displacement map 200 of the area including the current position of the vehicle 1 from the map management system 100. The unsprung displacement map 200 is stored in the memory device 72. Then, the control device 70 performs "preview control," a type of vibration damping control, based on the unsprung displacement map 200.

[0060] Figure 9 is a conceptual diagram illustrating the preview control. Figure 10 is a flowchart illustrating the preview control. The preview control will be explained with reference to Figures 9 and 10.

[0061] In step S31, the processor 71 obtains the current position P0 of each wheel 2. The relative positional relationship between the reference point of the vehicle position on vehicle 1 and each wheel 2 is known information. Based on this relative positional relationship and the vehicle position indicated by the position information 94, the position of each wheel 2 can be calculated.

[0062] In step S32, the processor 71 calculates the predicted passing position Pf of wheel 2 after the preview time tp. The preview time tp is set to be longer than, for example, the time required for the calculation and communication processing necessary to activate the actuator 3A of the suspension 3. The preview time tp may be fixed or variable depending on the situation. The preview distance Lp is given by the product of the preview time tp and the vehicle speed V. The predicted passing position Pf is the position forward of the preview distance Lp from the current position P0. As an alternative, the control device 70 may calculate a predicted travel route based on the vehicle speed V and the steering angle of wheel 2, and calculate the predicted passing position Pf based on the predicted travel route. If different unsprung displacement maps 200 are created according to the direction of travel φ, the predicted direction of travel of the vehicle 1 is also calculated in addition to the predicted passing position Pf.

[0063] In step S33, the processor 71 reads the unsprung displacement Zu at the predicted passing position Pf from the unsprung displacement map 200. If the unsprung displacement map 200 is created separately for each direction of travel φ, the unsprung displacement Zu is read from the unsprung displacement map 200 based on the combination of the predicted direction of travel and the predicted passing position Pf.

[0064] In step S34, the processor 71 decomposes the unsprung displacement Zu into in-phase inputs Zuin and out-of-phase inputs Zuan for the left and right wheels. The in-phase inputs Zufin and out-of-phase inputs Zufan for the left and right wheels on the front axle side are expressed, for example, by equations (1) and (2), and the in-phase inputs Zurin and out-of-phase inputs Zuran for the left and right wheels on the rear axle side are expressed by equations (3) and (4).

[0065]

number

[0066] In equations (1)-(4), Zufl represents the unsprung displacement Zu of the left front wheel 2FL, and Zufr represents the unsprung displacement Zu of the right front wheel 2FR, which together with the left front wheel 2FL constitute the front wheel. Zurl represents the unsprung displacement Zu of the left rear wheel 2RL, and Zurr represents the unsprung displacement Zu of the right rear wheel 2RR, which together with the left rear wheel 2RL constitute the rear wheel.

[0067] In another example, the processor 71 further decomposes the left and right wheel in-phase input Zuin into a front and rear wheel in-phase input (heave) Zuin derived from the same vertical displacement of the front and rear wheels of the vehicle 1, and a front and rear wheel out-of-phase input (pitch) Zuan derived from the different vertical displacements of the front and rear wheels. Here, the front and rear wheels refer to the combination of the left front wheel 2FL and the right front wheel 2FR, and the left rear wheel 2RL and the right rear wheel 2RR. In this case, the decomposed front and rear wheel in-phase input Zuin, i.e., the left and right wheel in-phase and front and rear wheel in-phase input Zuin-in, is expressed by the following equation (5). Also, the decomposed front and rear wheel out-of-phase input Zuan, i.e., the left and right wheel in-phase and front and rear wheel out-of-phase input Zuin-an, is expressed by the following equation (6).

[0068]

number

[0069] In step S35, the processor 71 determines whether additional filtering is required for the left and right wheel in-phase inputs Zufin on the front axle side and Zurin on the rear axle side. Specifically, the processor 71 determines that additional filtering is required if at least one of the following filter application conditions (i) and (ii) is met. (i) The in-phase input Zuin (Zufin or Zurin) for the left and right wheels is greater than or equal to the upper limit. (ii) The moving average of the in-phase inputs Zuin (Zufin or Zurin) for the left and right wheels is greater than or equal to the upper limit. The "upper limit" is pre-set as the unsprung displacement Zu that exceeds the actuator's capacity or suspension stroke. The moving average is calculated, for example, based on multiple left and right wheel in-phase inputs Zuin over a sampling period retrospectively from the predicted passing position Pf. Left and right wheel in-phase inputs Zuin at a time later than the preview time tp can also be read from the unsprung displacement map 200 and used in the calculation of the moving average.

[0070] If the result of the determination in step 35 is positive, the process proceeds to step S36. In step S36, the processor 71 performs additional filtering on the left and right wheel common-mode input Zuin. A second high-pass filter is applied to the left and right wheel common-mode input Zuin to cut out components below the second frequency (e.g., 0.5 Hz) that originate from altitude changes, etc. This second high-pass filter is a stronger high-pass filter than the first high-pass filter used in the filtering process in step S15 of Figure 3. Here, "stronger high-pass filter" means a high cutoff frequency (low frequency side), a high filter order, or a large number of filter stages.

[0071] As previously mentioned, the unsprung displacement Zu includes extremely low-frequency components (e.g., components below 0.5 Hz) originating from altitude changes, etc. However, these extremely low-frequency components also include the left and right wheel out-of-phase inputs. In this regard, according to the processing routine shown in Figure 10, steps S34, S35, and S36 perform additional filtering on the left and right wheel in-phase input Zuin. This removes the extremely low-frequency components originating from altitude changes, etc., from the left and right wheel in-phase input Zuin. On the other hand, no additional filtering is performed on the left and right wheel out-of-phase input Zuan. Therefore, components higher than the first frequency (e.g., 0.2 Hz) remain in the left and right wheel out-of-phase input Zuan.

[0072] In another example of step S34, in step S36, a third high-pass filter is applied to the left-right and front-rear wheel in-phase input Zuin-in, which is generated by decomposing the left-right and front-rear wheel in-phase input Zuin, to cut out components below the third frequency (e.g., 0.5 Hz) that originate from altitude changes, etc. On the other hand, a fourth high-pass filter is applied to the left-right and front-rear wheel in-phase input Zuin-in to cut out components below the fourth frequency (e.g., 0.4 Hz). In other words, the third high-pass filter is a stronger high-pass filter than the fourth high-pass filter. The fourth high-pass filter is also a stronger high-pass filter than the first high-pass filter used in the filtering process of step S15 in Figure 3.

[0073] The reason why a third high-pass filter, which is relatively strong in filtering inputs Zuin-in (where both left and right wheels are in phase and front and rear wheels are in phase), is applied, and why a fourth high-pass filter, which is relatively weak in filtering inputs Zuin-an (where both left and right wheels are in phase and front and rear wheels are out of phase), is applied, is the same reason as the reason for using the first and second high-pass filters differently.

[0074] If the result of the determination in step 35 is positive, the processor 71 performs additional filtering on the left and right wheel common-mode input Zuin in step S36. Otherwise, the processor 71 proceeds to step S37 without performing this additional filtering. However, the processor 71 may perform additional filtering on the left and right wheel common-mode input Zuin. In this case, the second high-pass filter may be used as a through-pass filter in the additional filtering process, or a fifth high-pass filter may be used to cut components below the fifth frequency (e.g., 0.3 Hz). The fifth high-pass filter is a weaker high-pass filter than the second high-pass filter.

[0075] When calculating the unsprung displacement Zu while vehicle 1 is in motion, a "phase shift" occurs due to the filtering process using a high-pass filter. Specifically, a "phase lead" occurs due to the high-pass filter. Therefore, in step S37, the processor 71 adjusts the preview time tp to cancel out the phase delay corresponding to the time constant of the high-pass filter applied in the additional filtering process. Specifically, the preview time tp is modified to be shorter by the time constant of the applied LPF. For this reason, the preview time tp is modified to be shorter the smaller the time constant is.

[0076] In step S38, the processor 71 calculates the target control force Fc_t of the actuator 3A of the suspension 3 based on the unsprung displacement Zu at the predicted passing position Pf. The target control force Fc_t is calculated, for example, using the following equations (7)-(10).

[0077]

number

[0078] In equations (7)-(10), Zufin and Zurin are the left and right wheel common-phase input Zuin after filtering using the second high-pass filter described in step 36, the left and right wheel common-phase input Zuin after the second high-pass filter has been passed through, or the left and right wheel common-phase input Zuin after filtering using the fifth high-pass filter. Furthermore, αfin is the left and right wheel common-phase input gain on the front axle side, αfan is the left and right wheel out-of-phase input gain on the front axle side, αrin is the left and right wheel common-phase input gain on the rear axle side, and αran is the left and right wheel out-of-phase input gain on the rear axle side.

[0079] If the left and right wheel common-phase input Zuin is decomposed, replace "left and right wheel common-phase input Zufin" in equations (7)-(8) with "left and right wheel common-phase and front and rear wheel common-phase input Zuin-in", "left and right wheel out-of-phase input Zufan" with "left and right wheel common-phase and front and rear wheel out-of-phase input Zuin-an", "left and right wheel common-phase input gain αfin" with "left and right wheel common-phase and front and rear wheel common-phase input gain αfrin", and "left and right wheel out-of-phase input gain αfan" with "left and right wheel common-phase and front and rear wheel out-of-phase input gain αfran". Furthermore, in equations (9)-(10), replace "left and right wheel in-phase input Zurin" with "left and right wheel in-phase and front and rear wheel in-phase input Zuin-in", replace "left and right wheel out-of-phase input Zuran" with "left and right wheel in-phase and front and rear wheel out-of-phase input Zurran", replace "left and right wheel in-phase input gain αrin" with "left and right wheel in-phase and front and rear wheel in-phase input gain αfrin", and replace "left and right wheel out-of-phase input gain αran" with "left and right wheel in-phase and front and rear wheel out-of-phase input gain αfran".

[0080] In step S39, the control device 70 controls the actuator 3A to generate a target control force Fc_t at the timing when the reference point Pr passes through the predicted passing position Pf. The timing when the reference point Pr passes through the predicted passing position Pf can be determined from the preview time tp.

[0081] By using the preview control based on the unsprung displacement map 200 described above, it becomes possible to effectively suppress vibrations of the vehicle 1 (supersprung structure 5). In particular, by using the unsprung displacement map 200 in which the left and right wheel inverse phase inputs remain in the time-series data of the unsprung displacement Zu, and by appropriately performing additional filtering on the left and right wheel in-phase inputs acquired from the unsprung displacement map 200 while the vehicle 1 is running, it becomes possible to appropriately reflect the left and right wheel in-phase input Zuin and the left and right wheel inverse phase input Zuan in the vibration damping control. [Explanation of symbols]

[0082] 1…Vehicle 2...wheels 3…Suspension 3A… Actuator 10…Vehicle control system 20... Vehicle condition sensor 30…Recognition sensor 40…Position sensor 50…Communication device 60... Running gear 70...Control device 80... Vehicle control program 90…Driving environment information 93... Surrounding Area Information 94…location information 100... Map Management System 110...Communication device 120… Processor 130...Storage device 140... Map management program 200...Unsprung displacement map Zu...Unsprung displacement Zuin...Same-phase input for left and right wheels Zuan... Left and right wheels in reverse phase input Zuin-in… Inputs that are in phase with both the left and right wheels and the front and rear wheels. Zuin-an…Left and right wheels in phase, front and rear wheels in opposite phase inputs.

Claims

1. A method for performing vibration control of a vehicle using a control map, which is executed by a computer, The control map includes a parameter map that shows the correspondence between position and parameters related to the vertical movement of each wheel of the vehicle. The parameter map is created or updated by filtering time-series data of parameters related to the vertical movement of each wheel of the vehicle. The filtering process includes a filtering process using a first high-pass filter that cuts out frequency components below a first frequency from parameters related to the vertical movement of each wheel of the vehicle. The method described above is While the vehicle is in motion, the predicted passing positions of each wheel of the vehicle from the current time to the time after the preview period are calculated. From the parameter map, parameters related to the vertical movement of each wheel of the vehicle at its predicted passing position are obtained, Based on parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel of the vehicle, and parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel of the vehicle which constitutes the left and right wheels together with the first wheel, the in-phase input of the left and right wheels derived from the same vertical displacement of the first wheel and the second wheel is calculated. Based on parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel and parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel, the left and right wheel out-of-phase inputs derived from the different vertical displacements of the first and second wheels are calculated. This includes calculating the control amounts of the actuators that control the suspension stroke of the first and second wheels based on the opposite-phase inputs of the left and right wheels of the first and second wheels and the same-phase inputs of the left and right wheels of the first and second wheels. A method for controlling vibration damping in a vehicle, characterized by the features described above.

2. The method according to claim 1, The method further includes determining whether additional filtering is required for the in-phase inputs of the left and right wheels of the first and second wheels, The additional filtering process includes filtering using a second high-pass filter that cuts out frequency components of a second frequency or lower that are higher than the first frequency from the in-phase inputs of the left and right wheels of the first and second wheels, If it is determined whether the additional filtering process is necessary, the control amounts of the actuators that control the suspension stroke of the first and second wheels are calculated based on the out-of-phase inputs of the first and second wheels and the in-phase inputs of the first and second wheels after the filtering process, including the additional filtering process. A method for controlling vibration damping in a vehicle, characterized by the features described above.

3. The method according to claim 2, Determining whether additional filtering is required for the left and right wheel in-phase inputs of the first and second wheels includes determining whether the filter application conditions are met. The conditions for applying the filter are satisfied if at least one of the following is met: the in-phase inputs of the left and right wheels of the first and second wheels are greater than or equal to the upper limit, and the moving average of the in-phase inputs of the left and right wheels of the first and second wheels is greater than or equal to the upper limit. A method for controlling vibration damping in a vehicle, characterized by the features described above.

4. The method according to claim 2, The method further includes reducing the preview time to cancel out the phase lead of the left and right wheel in-phase inputs of the first and second wheels, corresponding to the time constant of the second high-pass filter used in the additional filtering process. A method for controlling vibration damping in a vehicle, characterized by the features described above.

5. A method according to claim 1 or 2, The aforementioned method further, Based on parameters related to the vertical movement of the third wheel at the predicted passing position of the third wheel, which constitutes the front and rear wheels of the vehicle, and parameters related to the vertical movement of the fourth wheel at the predicted passing position of the fourth wheel, which constitutes the left and right wheels of the vehicle, the same phase input of the left and right wheels originating from the same vertical displacement of the third wheel and the fourth wheel is calculated. Based on parameters related to the vertical movement of the third wheel at the predicted passing position of the third wheel and parameters related to the vertical movement of the fourth wheel at the predicted passing position of the fourth wheel, the left and right wheel out-of-phase inputs resulting from the different vertical displacements of the third and fourth wheels are calculated. Based on the in-phase inputs of the left and right wheels of the first and second wheels, and the in-phase inputs of the left and right wheels of the third and fourth wheels, the in-phase inputs of the left and right wheels and the front and rear wheels derived from the same vertical displacement of the first and second wheels and the same vertical displacement of the first and second wheels and the third and fourth wheels are calculated. The method includes calculating in-phase inputs for the left and right wheels of the first and second wheels, and out-of-phase inputs for the left and right wheels of the third and fourth wheels, based on the same vertical displacement of the first and second wheels, and the different vertical displacements of the first and second wheels and the third and fourth wheels, and the out-of-phase inputs for the front and rear wheels. Calculating the control amount of each actuator that controls the suspension stroke of the first and second wheels includes calculating the control amount based on the left and right wheel opposite-phase inputs and the left and right wheel same-phase and front and rear wheel same-phase inputs, and calculating the control amount based on the left and right wheel opposite-phase inputs and the left and right wheel same-phase and front and rear wheel opposite-phase inputs. A method for controlling vibration damping in a vehicle, characterized by the features described above.

6. The method according to claim 5, The method further includes determining whether additional filtering is required for the in-phase inputs of the left and right wheels of the first and second wheels, The additional filtering process includes filtering using a second high-pass filter that cuts out frequency components of a second frequency or lower that are higher than the first frequency from the in-phase inputs of the left and right wheels of the first and second wheels, Determining whether additional filtering is necessary for the left and right wheel in-phase inputs of the first and second wheels includes determining whether additional filtering is necessary for the left and right wheel in-phase and front and rear wheel in-phase inputs, and determining whether additional filtering is necessary for the left and right wheel in-phase and front and rear wheel out-of-phase inputs. If the necessity of the additional filtering process is determined, the control amounts of the actuators that control the suspension stroke of the first and second wheels are calculated based on the left and right wheel opposite-phase inputs of the first and second wheels, the left and right wheel same-phase inputs and front and rear wheel same-phase inputs after the filtering process including the additional filtering process, and the left and right wheel opposite-phase inputs of the first and second wheels, and the left and right wheel same-phase inputs and front and rear wheel opposite-phase inputs after the filtering process including the additional filtering process. A method for controlling vibration damping in a vehicle, characterized by the features described above.

7. The method according to claim 6, The additional filtering process for the in-phase inputs of the left and right wheels and the front and rear wheels includes filtering using a third high-pass filter that cuts out frequency components of a third frequency or lower that are higher than the first frequency. The additional filtering process for the left and right wheel in-phase and front and rear wheel out-of-phase inputs includes filtering using a fourth high-pass filter that cuts out frequency components below the fourth frequency between the first and third frequencies. A method for controlling vibration damping in a vehicle, characterized by the features described above.

8. The method according to claim 7, The method further includes reducing the preview time to cancel out the phase lead of the left and right wheel in-phase and front and rear wheel in-phase inputs, corresponding to the time constant of the third high-pass filter used in the additional filtering process for the left and right wheel in-phase and front and rear wheel in-phase inputs. A method for controlling vibration damping in a vehicle, characterized by the features described above.

9. The method according to claim 7, The method further includes reducing the preview time to cancel out the phase lead of the left and right wheel in-phase and front and rear wheel out-of-phase inputs, corresponding to the time constant of the fourth high-pass filter used in the additional filtering process for the left and right wheel in-phase and front and rear wheel out-of-phase inputs. A method for controlling vibration damping in a vehicle, characterized by the features described above.

10. A system that performs vibration control of a vehicle using a control map, Actuators that control the suspension stroke of each wheel of the vehicle, One or more storage devices in which the control map is stored, The system includes one or more processors that perform vibration control processing of the vehicle by controlling the actuator based on the control map, The control map includes a parameter map that shows the correspondence between position and parameters related to the vertical movement of each wheel of the vehicle. The parameter map is created or updated by filtering time-series data of parameters related to the vertical movement of each wheel of the vehicle. The filtering process includes a filtering process that cuts out frequency components below a first frequency from parameters related to the vertical movement of each wheel of the vehicle. The vibration damping control process, While the vehicle is in motion, the predicted passing positions of each wheel of the vehicle from the current time to the time after the preview period are calculated. From the parameter map, parameters related to the vertical movement of each wheel of the vehicle at its predicted passing position are obtained, Based on parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel of the vehicle, and parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel of the vehicle which constitutes the left and right wheels together with the first wheel, the in-phase input of the left and right wheels derived from the same vertical displacement of the first wheel and the second wheel is calculated. Based on parameters related to the vertical movement of the first wheel at the predicted passing position of the first wheel and parameters related to the vertical movement of the second wheel at the predicted passing position of the second wheel, the left and right wheel out-of-phase inputs derived from the different vertical displacements of the first and second wheels are calculated. This includes calculating the control amounts of the actuators that control the suspension stroke of the first and second wheels based on the opposite-phase inputs of the left and right wheels of the first and second wheels and the same-phase inputs of the left and right wheels of the first and second wheels. A vehicle vibration control system characterized by the following features.

11. The system according to claim 10, The vibration damping control process further includes determining whether additional filtering is necessary for the in-phase inputs of the left and right wheels of the first and second wheels. The additional filtering process includes filtering using a second high-pass filter that cuts out frequency components of a second frequency or lower that are higher than the first frequency from the in-phase inputs of the left and right wheels of the first and second wheels, If it is determined whether the additional filtering process is necessary, the control amounts of the actuators that control the suspension stroke of the first and second wheels are calculated based on the out-of-phase inputs of the first and second wheels and the in-phase inputs of the first and second wheels after the filtering process, including the additional filtering process. A vehicle vibration control system characterized by the following features.

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