JP2023046927A - Vehicle suspension control device, vehicle control system, and vehicle suspension control method - Google Patents

Abstract

To suppress deterioration of a damping effect caused by the influence of steps existing in a road surface data map.SOLUTION: A vehicle suspension control device includes an actuator for controlling a suspension stroke, and an electronic control unit (ECU). The ECU performs: acquisition processing of acquiring front road surface data, which is data of road surface displacement-related values on a front road surface including a predicted passing position, from a road surface data map mapped with the road surface displacement-related values being associated with data stored positions; determination processing of determining whether or not a vehicle is traveling so as to continuously use the road surface displacement-related values located at the boundaries of steps of the road surface displacement-related values existing in the front road surface data; filtering processing for applying a low-pass filter to the front road surface data if the determination result is affirmative; and control processing for executing preview damping control based on the front road surface data after the filtering processing if the determination result is affirmative.SELECTED DRAWING: Figure 11

Description

The present disclosure relates to a vehicle suspension control device, a vehicle control system, and a vehicle suspension control method that perform preview damping control to reduce vibration of a sprung structure of a vehicle.

Patent Literature 1 discloses an active suspension control device. This control device determines whether time-series data of road surface displacement in front of the vehicle detected by a road surface sensor attached to the front of the vehicle is normal. Then, when the detection of the road surface displacement is abnormal, the control device switches the control of the suspension of the rear wheels to the control based on the vertical acceleration at the position of the front wheels. This prevents deterioration of the ride comfort performance of the vehicle when the road surface sensor does not accurately detect the displacement of the road surface.

JP-A-05-096922

In the preview damping control that reduces the vibration of the vehicle's sprung structure, the road surface displacement-related value related to the vertical displacement of the road surface is associated with the position in order to control the actuator that controls the suspension stroke of the controlled wheel. It is conceivable to use a road surface data map mapped by A step may occur in the road surface displacement-related values on the road surface data map. If the vehicle continuously uses road surface displacement-related values located at the boundary of bumps, the damping effect of the preview damping control may decrease, or active vibration of the vehicle body may occur. .

The present disclosure has been made in view of the problems as described above, and its purpose is to reduce the damping effect or reduce the active vibration of the vehicle body due to the influence of steps in the road surface displacement-related values existing on the road surface data map. To provide a technique capable of suppressing the occurrence of

A vehicle suspension control device according to the present disclosure includes an actuator and an electronic control unit. The actuator controls the suspension stroke of the controlled wheel. The electronic control unit performs preview damping control to reduce vibration of the sprung structure of the vehicle by controlling the actuator. The electronic control unit performs acquisition processing, determination processing, filtering processing, and control processing. In the acquisition process, from the road surface data map in which the road surface displacement related values related to the vertical displacement of the road surface are mapped with the data storage positions, the road surface ahead including the predicted passing position of the control target wheel after the preview time from the current time is obtained. This is a process of acquiring front road surface data, which is data of road surface displacement related values in . The determination process is a process for determining whether or not the vehicle is traveling so as to continuously use the road surface displacement-related value located at the boundary of the step of the road surface displacement-related value existing on the front road surface data. The filtering process is a process of applying a low-pass filter to forward road surface data when the determination result of the determination process is affirmative. The control process is a process of executing preview damping control based on the forward road surface data after the filtering process when the determination result of the determination process is affirmative.

In the filtering process, the electronic control unit may increase the strength of the low-pass filter when the index value indicating the magnitude of the high-frequency component of the forward road surface data is large compared to when the index value is small.

In the filtering process, the electronic control unit may increase the number of times of applying the low-pass filter to the forward road surface data when the index value is large compared to when the index value is small.

When the strength level value of the low-pass filter is defined as a positive number of 1 or more, in the filtering process, the electronic control unit divides adjacent natural numbers and decimal numbers positioned between adjacent natural numbers as the index value increases. The level value may be continuously increased while using.

If the determination result of the determination process is affirmative, the electronic control unit may increase the preview time so as to offset the phase lag of the forward road surface data according to the time constant of the low-pass filter applied in the filtering process. .

In the determination process, the electronic control unit determines that the first index value indicating the magnitude of the high frequency component of the forward road surface data is greater than a threshold and the second index value indicating the magnitude of the frequency component on the lower side than the high frequency component. is equal to or less than a threshold, it may be determined that the vehicle is traveling so as to continuously use the road surface displacement-related value located at the boundary.

A vehicle control system according to the present disclosure includes the vehicle suspension control device described above. A vehicle suspension control device receives a road surface data map generated by the map management system from a map management system that generates a road surface data map.

The map management system selects a data storage position where a difference in road surface displacement related value between adjacent data storage positions on the road surface data map is equal to or greater than a threshold value. Edge detection processing specified as an edge position of the data map, and edge presence/absence information indicating whether or not the data storage position is an edge position, which is processing executed for each of the data storage positions, are associated with the data storage position. and may be performed. In the determination process, when the electronic control unit continuously detects that the data storage position corresponding to the predicted passing position is the edge position for a predetermined number of times or more, the road surface displacement-related value at the boundary is continuously determined. It may be determined that the vehicle is running so as to be used for

A vehicle suspension control method according to the present disclosure performs preview damping control that reduces vibration of a sprung structure of a vehicle by controlling an actuator that controls a suspension stroke of a wheel to be controlled. This control method is based on a road surface data map in which road surface displacement-related values related to the vertical displacement of the road surface are mapped with data storage positions, and the road surface ahead including the predicted passage position of the wheel to be controlled after the preview time from the current time. Acquisition processing for acquiring front road surface data, which is data of road surface displacement-related values in the vehicle, and road surface displacement-related values located at the boundary of steps of road surface displacement-related values existing on the front road surface data are continuously used. a determination process for determining whether or not the vehicle is running, a filtering process for applying a low-pass filter to the front road surface data if the determination result of the determination process is positive, and a determination process if the determination result of the determination process is positive. In some cases, control processing for executing preview damping control based on front road surface data after filtering processing.

According to each of the vehicle suspension control device, the vehicle control system, and the vehicle suspension control method according to the present disclosure, the road surface displacement-related value located at the boundary of the step of the road surface displacement-related value existing on the front road surface data is continuously When it is determined that the vehicle is running as intended, a filtering process of applying a low-pass filter to forward road surface data used as a basis for preview damping control is performed. As a result, it is possible to suppress the deterioration of the damping effect or the occurrence of active vibration of the vehicle body due to the influence of the step.

1 is a schematic diagram showing a configuration example of a vehicle according to an embodiment; FIG. 1 is a conceptual diagram showing a configuration example of a suspension according to an embodiment; FIG. It is a flow chart which shows an example of unsprung displacement calculation processing. 1 is a block diagram showing a configuration example of a vehicle control system according to an embodiment; FIG. 3 is a block diagram showing an example of driving environment information indicating the driving environment of a vehicle; FIG. 1 is a block diagram showing a configuration example of a map management system according to an embodiment; FIG. It is a conceptual diagram for explaining an unsprung displacement map. 4 is a flowchart briefly showing map generation/update processing according to the embodiment; FIG. 4 is a conceptual diagram for explaining preview damping control; FIG. 4 is a conceptual diagram for explaining a boundary between steps S existing on an unsprung mass displacement map; 7 is a flowchart showing an example of processing related to preview damping control according to the embodiment; 10 is a flowchart showing an example of processing of boundary determination method A of level difference S. FIG. FIG. 10 is a diagram for explaining specific examples 1 and 2 of changing the strength of the LPF according to the magnitude of the index value Xh; FIG. 10 is a block diagram showing processing for continuously changing the strength of the LPF according to the index value Xh; 10 is a flowchart showing an example of processing of boundary determination method B of level difference S. FIG. 10 is a flowchart showing an example of processing of boundary determination method B of level difference S. FIG.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. When referring to numbers such as the number, quantity, amount, range, etc. of each element in the embodiments shown below, unless otherwise specified or clearly specified in principle, the number referred to However, the technical idea according to the present disclosure is not limited to this.

1. Suspension and Road Surface Displacement Related Values FIG. 1 is a schematic diagram showing a configuration example of a vehicle 1 according to the present embodiment. A vehicle 1 has wheels 2 and suspensions 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. Suspensions 3FL, 3FR, 3RL, and 3RR are provided for the left front wheel 2FL, right front wheel 2FR, left rear wheel 2RL, and right rear wheel 2RR, respectively. In the following description, each wheel will be called a wheel 2 and each suspension will be called a suspension 3 unless there is a particular need to distinguish them.

FIG. 2 is a conceptual diagram showing a configuration example of the suspension 3 according to the embodiment. Suspension 3 is provided to connect between unsprung structure 4 and sprung structure 5 of vehicle 1 . The unsprung structure 4 includes wheels 2 . The suspension 3 includes springs 3S, dampers (shock absorbers) 3D, and actuators 3A. The spring 3S, damper 3D, and actuator 3A are provided in parallel between the unsprung structure 4 and the sprung structure 5. As shown in FIG. Actuator 3 A controls the stroke of suspension 3 . A spring constant of the spring 3S is K. The damping coefficient of damper 3D is C. The actuator 3</b>A applies a vertical control force Fc between the unsprung structure 4 and the sprung structure 5 .

More specifically, the actuator 3A is, for example, an electric or hydraulic active actuator (actuator constituting a so-called full active suspension). Alternatively, the actuator 3A may be, for example, an actuator that varies the damping force generated by the damper 3D, or an actuator of an active stabilizer device.

Here, we define the terms. "Road surface displacement Zr" is the vertical displacement of the road surface RS. The “unsprung displacement Zu” is the vertical displacement of the unsprung structure 4 . The “sprung displacement Zs” is the vertical displacement of the sprung structure 5 . The “unsprung speed Zu′” is the vertical speed of the unsprung structure 4 . The “sprung speed Zs′” is the vertical speed of the sprung structure 5 . The “unsprung acceleration Zu″” is the vertical acceleration of the unsprung structure 4 . The “sprung acceleration Zs″” is the vertical acceleration of the sprung structure 5 . The sign of each parameter is positive for upward and negative for downward.

The wheels 2 move on the road surface RS. In the following description, the value related to the road surface displacement Zr is called "road surface displacement related value". The road surface displacement-related values include the road surface displacement Zr, the road surface displacement speed Zr′ which is the time differential value of the road surface displacement Zr, the unsprung displacement Zu, the unsprung speed Zu′, the unsprung acceleration Zu″, and the sprung displacement Zs. , sprung speed Zs′, sprung acceleration Zs″, and the like. The road surface displacement related value can also be said to be a “vertical motion parameter” which is a parameter related to the vertical motion of the wheel 2 .

As an example, the following description considers a case where the road surface displacement related value is the unsprung displacement Zu. For generalization, "unsprung displacement" in the following description should be read as "road surface displacement related value".

FIG. 3 is a flowchart showing an example of unsprung displacement calculation processing.

In step S<b>11 , the sprung acceleration Zs″ is detected by the sprung acceleration sensor 22 installed on the sprung structure 5 . In step S12, the sprung displacement Zs is calculated by second-order integration of the sprung acceleration Zs''.

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

In step S14, filtering processing is performed on the time-series data of the sprung mass displacement Zs in order to suppress the influence of sensor drift and the like. Similarly, in step S15, filtering processing is performed on the time-series data of the stroke ST. For example, the filter is a bandpass filter that passes signal components in a specific frequency band. The specific frequency band may be set to include the sprung resonance frequency of the vehicle 1 . For example, the specific frequency band is 0.3-10 Hz. In addition, these filtering processes are performed separately from filtering process PR3, which will be described later.

In step S16, the difference between the sprung displacement Zs and the stroke ST is calculated as the unsprung displacement Zu.

Instead of steps S14 and S15, filtering processing may be performed on the time-series data of the unsprung displacement Zu calculated in step S16.

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

2. Vehicle control system 2-1. Configuration Example FIG. 4 is a block diagram showing a configuration example of the vehicle control system 10 according to the embodiment. A vehicle control system 10 is mounted on the 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 traveling device 60, and an electronic control unit (ECU)70.

Vehicle state sensor 20 detects the state of vehicle 1 . The vehicle state sensor 20 includes a vehicle speed sensor (wheel speed sensor) 21 that detects the vehicle speed V of the vehicle 1, a sprung acceleration sensor 22 that detects the sprung acceleration Zs'', and the like. Vehicle state sensor 20 may include stroke sensor 23 that detects stroke ST. Vehicle state sensor 20 may include an unsprung acceleration sensor. In addition, the vehicle state sensor 20 includes a lateral acceleration sensor, a yaw rate sensor, a steering angle sensor, and the like.

The recognition sensor 30 recognizes (detects) the circumstances around the vehicle 1 . Examples of the recognition sensor include a camera, LIDAR (Laser Imaging Detection and Ranging), radar, and the like.

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

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

The traveling device 60 includes a steering device 61, a driving device 62, a braking device 63, and a suspension 3 (see FIG. 2). The steering device 61 steers the wheels 2 . For example, the steering device 61 includes a power steering (EPS: Electric Power Steering) device. The driving device 62 is a power source that generates driving force. Examples of the driving device 62 include an engine, an electric motor, an in-wheel motor, and the like. The braking device 63 generates braking force.

The ECU 70 is a computer that controls the vehicle 1 . The ECU 70 includes one or more processors 71 (hereinafter simply referred to as processors 71) and one or more storage devices 72 (hereinafter simply referred to as storage devices 72). The processor 71 executes various processes. For example, the processor 71 includes a CPU (Central Processing Unit). The storage device 72 stores various information necessary for processing by the processor 71 . Examples of the storage device 72 include volatile memory, nonvolatile memory, HDD (Hard Disk Drive), SSD (Solid State Drive), and the like. A plurality of ECUs 70 may be provided.

Vehicle control program 80 is a computer program for controlling vehicle 1 and is executed by processor 71 . A vehicle control program 80 is stored in the storage device 72 . Alternatively, vehicle control program 80 may be recorded on a computer-readable recording medium. The functions of the ECU 70 are realized by the processor 71 executing the vehicle control program 80 . The ECU 70 corresponds to an example of an "electronic control unit" included in the "vehicle suspension control device" according to the present disclosure.

2-2. Driving Environment Information FIG. 5 is a block diagram showing an example of driving environment information 90 indicating the driving environment of the vehicle 1 . Driving environment information 90 is stored in storage device 72 . The driving environment information 90 includes map information 91 , vehicle state information 92 , surrounding situation information 93 and position information 94 .

Map information 91 includes a general navigation map. The map information 91 may indicate lane layout, road shape, and the like. The map information 91 may include position information such as white lines, traffic lights, signs, landmarks, and the like. Map information 91 is obtained from a map database. Note that the map database may be installed in the vehicle 1 or may be stored in an external management server. In the latter case, the ECU 70 communicates with the management server and acquires the necessary map information 91 .

The map information 91 further includes an "unsprung displacement map 200". Details of the unsprung displacement map 200 will be described later.

The vehicle state information 92 is information indicating the state of the vehicle 1 . The ECU 70 acquires vehicle state information 92 from the vehicle state sensor 20 . For example, the vehicle state information 92 includes vehicle speed V, sprung acceleration Zs'', stroke ST, lateral acceleration, yaw rate, steering angle, and the like. Vehicle speed V may be calculated from the vehicle position detected by position sensor 40 . The ECU 70 may calculate the unsprung displacement Zu by the method shown in FIG. In that case, the vehicle state information 92 also includes the unsprung displacement Zu calculated by the ECU 70 .

The surrounding situation information 93 is information indicating the surrounding situation of the vehicle 1 . The ECU 70 recognizes the situation 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 LIDAR.

The surrounding situation information 93 further includes “object information” regarding objects around the vehicle 1 . Objects include pedestrians, bicycles, other vehicles (leading vehicles, parked vehicles, etc.), road structure (white lines, curbs, guardrails, walls, median strips, roadside structures, etc.), signs, poles, obstacles, etc. are exemplified. The object information indicates relative positions and relative velocities of objects with respect to the vehicle 1 . For example, by analyzing image information obtained by a camera, an object can be identified and the relative position of the object can be calculated. Also, based on the point cloud information obtained by LIDAR, an object can be identified and the relative position and relative velocity of the object can be obtained.

The position information 94 is information indicating the position and orientation of the vehicle 1 (vehicle traveling direction). The ECU 70 acquires the position information 94 from the measurement result of the position sensor 40 such as a GNSS receiver. As another example, the ECU 70 may acquire the position information 94 by dead reckoning. As still another example, the ECU 70 may acquire highly accurate position information 94 by well-known self-position estimation processing (localization) using object information and map information 91 .

2-3. The vehicle control ECU 70 executes vehicle travel control for controlling travel of the vehicle 1 . Vehicle travel control includes steering control, drive control, and braking control. The ECU 70 executes vehicle travel control by controlling the travel device 60 (the steering device 61, the drive device 62, and the braking device 63). The ECU 70 may perform driving support control to support driving of the vehicle 1 based on the driving environment information 90 . Examples of driving support control include lane keeping control, collision avoidance control, automatic driving control, and the like.

Furthermore, the ECU 70 controls the suspension 3 . Specifically, the ECU 70 performs damping control for suppressing vibration of the vehicle 1 by controlling the suspension 3 . The ECU 70 controls the actuator 3A to generate a vertical control force Fc between the unsprung structure 4 and the sprung structure 5 (see FIG. 2). Damping control includes "preview damping control" to be described later.

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

Map management system 100 includes communication device 110 . A communication device 110 is connected to a communication network NET. For example, the communication device 110 communicates with many vehicles 1 via the communication network NET.

The map management system 100 further includes one or more processors 120 (hereinafter simply referred to as processors 120) and one or more storage devices 130 (hereinafter simply referred to as storage devices 130). Processor 120 executes various types of information processing. For example, processor 120 includes a CPU. The storage device 130 stores various map information. The storage device 130 also stores various information necessary for processing by the processor 120 . Examples of the storage device 130 include volatile memory, nonvolatile memory, HDD, SSD, and the like.

Map management program 140 is a computer program for map management and is executed by processor 120 . A map management program 140 is stored in the storage device 130 . Alternatively, map management program 140 may be recorded on a computer-readable recording medium. The functions of the map management system 100 are implemented by the processor 120 executing the map management program 140 .

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

3-2. Unsprung displacement map (road surface data map)
One of the map information managed by the map management system 100 is the "unsprung displacement map 200". The unsprung displacement map 200 is a map regarding the unsprung displacement Zu (road surface displacement related value). The unsprung displacement map 200 is stored in the storage device 130 . The unsprung displacement map 200 corresponds to an example of "a road surface data map in which road surface displacement related values related to the vertical displacement of the road surface are mapped in association with data storage positions" according to the present disclosure.

FIG. 7 is a conceptual diagram for explaining the unsprung displacement map 200. FIG. The XY plane represents the horizontal plane. For example, the absolute coordinate system on the horizontal plane is defined by latitude and longitude directions, and the data storage position on the road surface is defined by latitude and longitude. The unsprung displacement map 200 represents at least the correspondence relationship between the data storage position (X, Y) and the unsprung displacement Zu. In other words, the unsprung displacement map 200 represents the unsprung displacement Zu as a function of at least the data storage location (X,Y).

The road area may be divided into meshes on the horizontal plane. That is, the road area may be divided into a plurality of unit areas (hereinafter referred to as "road surface sections M") on the horizontal plane. The road surface section M is, for example, square. The length of one side of the square is, for example, 10 cm. The unsprung displacement map 200 represents the correspondence relationship between the position of the road surface section M (that is, the data storage position) and the unsprung displacement Zu. The position of the road surface section M may be defined by the representative position (eg, center position) of the road surface section M, or by the range of the road surface section M (latitude range, longitude range). The unsprung displacement Zu of the road surface section M is, for example, the average value of the unsprung displacements Zu obtained within the road surface section M. As the road surface segment M becomes smaller, the resolution of the unsprung displacement map 200 increases.

3-3. Map Generation/Update Processing Processor 120 collects information from multiple vehicles 1 via communication device 110 . The processor 120 then generates and updates the unsprung displacement map 200 based on information collected from many vehicles 1 . An example of map generation/update processing will be described in more detail below.

A position in the unsprung displacement map 200 is a position through which the wheel 2 has passed. 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 in the vehicle 1 and each wheel 2 is known information. Based on the relative positional relationship and the vehicle position indicated by the position information 94, the position of each wheel 2 can be calculated.

The unsprung displacement Zu is calculated by the method shown in FIG. That is, by using the vehicle state sensor 20 mounted on the vehicle 1, the sprung displacement Zs and the stroke ST are obtained. These sprung displacement Zs and stroke ST are called "sensor base information" for convenience. The unsprung displacement Zu is calculated based on this sensor base information.

For example, while the vehicle 1 is running, the ECU 70 of the vehicle control system 10 calculates the unsprung displacement Zu in real time based on the sensor base information. Further, the ECU 70 associates the wheel position and the unsprung displacement Zu at the same timing. Then, the ECU 70 transmits to the map management system 100 a set of time-series data of the wheel position and time-series data of the unsprung displacement Zu. The processor 120 of the map management system 100 generates and updates the unsprung displacement map 200 based on the wheel position time series data and the unsprung displacement Zu time series data.

As another example, the ECU 70 of the vehicle control system 10 associates wheel positions and sensor-based information at the same timing. Then, the ECU 70 transmits to the map management system 100 a set of the wheel position time-series data and the sensor-based information time-series data. The processor 120 of the map management system 100 calculates the unsprung displacement Zu based on the received sensor-based information. Further, the processor 120 generates and updates the unsprung displacement map 200 based on the time series data of the wheel position and the time series data of the unsprung displacement Zu.

Note that when calculating the unsprung displacement Zu in the map management system 100, since there is no restriction on the processing time, filtering processing can be performed using a zero-phase filter. By using a zero-phase filter, "out of phase" can be prevented.

FIG. 8 is a flowchart briefly showing map generation/update processing according to the embodiment.

In step S<b>100 , 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 (for example, sprung displacement Zs and stroke ST) necessary for calculating unsprung displacement Zu. Alternatively, the map update information may include time-series data of the unsprung displacement Zu calculated by the ECU 70 of the vehicle control system 10 .

In step S200, the processor 120 of the map management system 100 generates/updates the unsprung displacement map 200 based on the map update information.

3-4. Modification The vehicle control system 10 of the vehicle 1 may hold a database of the unsprung displacement map 200 and generate/update its own unsprung displacement map 200 . That is, the map management system 100 may be included in the vehicle control system 10. FIG.

4. Preview Damping Control Using Unsprung Displacement Map The ECU 70 of the vehicle control system 10 communicates with the map management system 100 via the communication device 50 . The ECU 70 acquires the 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 storage device 72 . Based on the unsprung mass displacement map 200, the ECU 70 then executes "preview damping control," which is a type of damping control.

4-1. Overview of Preview Damping Control FIG. 9 is a conceptual diagram for explaining preview damping control. Note that preview damping control is executed to reduce vibration of the sprung structure 5 . The preview damping control may be executed for each of the four wheels 2, for example. Also, the wheels targeted for preview damping control may be, for example, only the two front wheels 2FL and 2FR or only the two rear wheels 2RL and 2RR.

In preview damping control, the ECU 70 acquires the current position P0 of each wheel 2 . The relative positional relationship between the vehicle position reference point of the vehicle 1 and each wheel 2 is known information. Based on the relative positional relationship and the vehicle position indicated by the position information 94, the position of each wheel 2 can be calculated.

Next, the ECU 70 calculates a predicted passing position Pf of the wheels 2 after the preview time tp from the current time. The preview time tp is preset to be, for example, the time required for the ECU 70 to specify the predicted passing position Pf until the actuator 3A of the suspension 3 outputs the control force Fc corresponding to the target control force Fc_t. . 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 a position ahead of the current position P0 by the preview distance Lp along the predicted movement course along which the wheels 2 are predicted to move in the traveling direction of the vehicle. The predicted movement course can be specified based on the traveling direction Td of the vehicle 1 and the current position P0 of the wheels 2, for example. The traveling direction T can be specified, for example, by the following method. That is, the ECU 70 maps the current position P0 of the previous time step and the current position P0 of the current time step on the map information 91, and then moves from the current position of the previous time step to the current position P0 of the current time step. The direction is specified as the traveling direction Td. As a modification, the ECU 70 may calculate the predicted travel route based on the vehicle speed V and the steering angle of the wheels 2, and calculate the predicted passing position Pf based on the predicted travel route.

Next, the ECU 70 reads the unsprung displacement Zu at the predicted passing position Pf from the unsprung displacement map 200 . That is, the ECU 70 receives the unsprung displacement map 200 from the map management system 100 . Then, the ECU 70 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. Target control force Fc_t is calculated, for example, as follows. This target control force Fc_t corresponds to the required value of the control force Fc required for the preview damping control (that is, the required control amount).

An equation of motion for the sprung structure 5 (see FIG. 2) is represented by the following equation (1).

In equation (1), m is the mass of the sprung structure 5, C is the damping coefficient of the damper 3D, K is the spring constant of the spring 3S, and Fc is the vertical control force generated by the actuator 3A. Fc. If the vibration of the sprung structure 5 is completely canceled by the control force Fc (Zs''=0, Zs'=0, Zs=0), the control force Fc is expressed by the following equation (2). be.

A control force Fc that provides at least a damping effect is represented by the following equation (3).

In equation (3), the gain α is greater than 0 and 1 or less, and the gain β is also greater than 0 and 1 or less. When the derivative term in equation (3) is omitted, at least the control force Fc that provides the damping effect is expressed by the following equation (4).

The ECU 70 calculates the target control force Fc_t according to the above formula (3) or (4). That is, the ECU 70 substitutes the unsprung displacement Zu at the predicted passing position Pf into the equation (3) or (4) to calculate the target control force Fc_t.

The ECU 70 then transmits a control command including the target control force Fc_t to the actuator 3A so that the actuator 3A generates the control force Fc corresponding to the target control force Fc_t. The actuator 3A generates a control force Fc corresponding to the target control force Fc_t at a timing after the preview time tp from the current time (that is, at a timing when the wheels 2 pass the predicted passing position Pf).

According to the preview damping control using the unsprung displacement map 200 described above, the vibration of the sprung structure 5 caused by the unsprung displacement Zu (road surface displacement related value) at the predicted passing position Pf of the wheel 2 can be generated at an appropriate timing. This makes it possible to effectively suppress the vibration of the sprung structure 5 (vehicle body).

4-2. Preview Damping Control Considering Steps Existing on Unsprung Displacement Map FIG. 10 is a conceptual diagram for explaining a boundary between steps S existing on an unsprung displacement map.

On the unsprung displacement map (road surface data map), a data step S (data height difference) may occur between the road surface sections M (data storage positions). More specifically, a step S of the unsprung displacement Zu (road surface displacement related value) can occur. A road section M1 hatched in FIG. 10 corresponds to a road section M having a large unsprung displacement Zu (that is, having an unsprung displacement Zu above the step S). On the other hand, the unhatched road section M2 corresponds to the road section M with a small unsprung displacement Zu (that is, having an unsprung displacement Zu below the step S).

Such a data step S may be caused by, for example, the following factors. That is, the step S may be caused by, for example, the unevenness of the actual road surface RS (for example, it may be caused to extend along a rut). The step S may also occur at the boundary between the area of the road surface section M having data on the unsprung displacement Zu and the area of the road surface section M having no such data. This is because the same initial value (for example, zero) is uniformly input as the unsprung displacement Zu in the road section M having no data. Furthermore, the step S can also occur inside the area of the road segment M with the data of the unsprung displacement Zu. Specifically, due to different effects of the filtering processing (see steps S14 and S15), the value of the unsprung mass displacement Zu data acquired for generating the unsprung mass displacement map 200 varies depending on the vehicle speed. Change. Therefore, when the unsprung displacement map 200 is generated by combining data acquired at different vehicle speeds, a step S may occur.

When a step S occurs, as illustrated in FIG. 10, at the boundary of the step S, the road surface section M1 with a large unsprung displacement Zu and the road surface section M2 with a small unsprung displacement Zu can be alternately switched. . For convenience of explanation, in FIG. 10, the boundary of the step S is represented by a road surface section M extending linearly in a row. However, the boundary may occur over multiple rows of road segments M or extend curvilinearly.

An arrow A shown in FIG. 10 indicates the trajectory of the wheel 2 . As exemplified by the arrow A, when the vehicle 1 travels continuously using the unsprung displacement Zu of the road surface section M (M1 and M2) located at the boundary of the step S, the road surface section M1 and the road surface section M2 and are switched at a high frequency. As a result, the unsprung displacement Zu obtained from the unsprung displacement map 200 for preview damping control fluctuates greatly in a short period. Hereinafter, this phenomenon will be referred to as "vibration of read data".

If the above-described "vibration of read data" occurs, the target control force Fc_t (required control amount) based on the unsprung displacement Zu will oscillate. As a result, the damping effect of the preview damping control may be reduced. In addition, active vibration of the sprung structure 5 (vehicle body) due to "vibration of read data" may occur.

In view of the above problems, the processing executed by the ECU 70 for preview damping control includes the following "acquisition processing PR1", "determination processing PR2", "filtering processing PR3", and "control processing PR4". there is

FIG. 11 is a flowchart illustrating an example of processing related to preview damping control according to the embodiment. The processing of this flowchart is repeatedly executed at each predetermined time step while the vehicle 1 is running.

In FIG. 11, the ECU 70 (processor 71) acquires the current position P0 of each wheel 2 (step S31), as described above with reference to FIG. 9, and then calculates the predicted passing position Pf of each wheel 2. (Step S32).

Next, in step S<b>33 , the ECU 70 acquires data of the unsprung displacement Zu on the front road surface including the predicted passing position Pf (hereinafter referred to as “front road surface data”) from the unsprung displacement map 200 .

More specifically, this forward road surface data can be obtained by, for example, the following method. That is, the data of the unsprung displacement Zu in a predetermined section located ahead of the current position P0 of the vehicle 1 in the direction of travel Td and the estimated time of arrival at each position of the wheel 2 moving along the direction of travel Td. The associated time-series data may be obtained as the forward road surface data. The predetermined section is, for example, a section starting at the predicted passage position Pf and ending at a position a predetermined distance away from the predicted passage position Pf along the traveling direction Td. The starting point may be the current position P0 or any position on the traveling direction Td between the current position P0 and the predicted passing position Pf. The predetermined distance may be set to a sufficiently large value, for example, compared to the preview distance Lp (see FIG. 9). Further, the predetermined section may be, for example, a section along the traveling direction Td, starting from the current position P0 and ending at the predicted passage position Pf. Further, the forward road surface data may be acquired by the following method, for example, in order to reduce the amount of data acquired at each time step and reduce the data processing load. That is, data (one point of data) of the unsprung displacement Zu at the predicted passing position Pf may be obtained from the unsprung displacement map 200 at each time step. Then, the data of the unsprung displacement Zu acquired at the current time step and the data of the unsprung displacement Zu acquired at a predetermined number of time steps before the previous time are combined to obtain the data of the unsprung displacement Zu in the predetermined section. may be acquired as the front road surface data. Note that the processing of steps S31 to S33 corresponds to an example of the “acquisition processing PR1”.

Next, in step S34, the ECU 70 executes determination processing PR2. Specifically, the ECU 70 determines whether the vehicle 1 is traveling so as to continuously use the unsprung displacement Zu located at the boundary of the step S existing on the front road surface data (see FIG. 10) (in other words, Then, it is determined whether or not the vehicle 1 is traveling along the boundary of the step S). This determination process PR2 can be performed using the following determination method A, for example.

If the above-described "vibration of read data" occurs, the high frequency component (high frequency vibration component) fh included in the forward road surface data acquired in step S33 increases. However, for example, while driving on a simply undulating road surface, not only the high frequency component fh but also the frequency components on the low side of the high frequency component fh are large even if the "vibration of the read data" does not occur. can be.

Therefore, in determination method A, the ECU 70 determines that an index value (first index value) indicating the magnitude of the high-frequency component fh of the acquired front road surface data is larger than a threshold, and that the frequency component on the low-frequency side is lower than the high-frequency component fh. It is determined whether or not the index value (second index value) indicating the magnitude of is equal to or less than the threshold. Note that in a specific example of determination method A described below with reference to FIG. used. However, the determination method A only needs to know that only the high frequency component fh is increased. Therefore, the number of frequency components on the lower frequency side than the high frequency component fh may be one or three or more instead of two.

FIG. 12 is a flow chart showing an example of the process of the method A for determining the boundary of the step S. As shown in FIG. The processing of this flowchart is executed in parallel with the processing of the flowchart shown in FIG. 11 while the vehicle 1 is running.

In step S41, the ECU 70 uses band-pass filters corresponding to the high-frequency component fh, intermediate-frequency component fm, and low-frequency component fl to extract the frequency components fh, fm, and fl are extracted (obtained). The high frequency band corresponding to the high frequency component fh is determined so as to be a suitable frequency band for identifying the high frequency component fh that increases due to "vibration of read data". More specifically, in the example using pre-filtering (see steps S14 and S15), signal components in the frequency band above 10 Hz are attenuated. However, when "vibration of read data" occurs, the signal component (vibration component) in the frequency band of 10 Hz or higher significantly increases. Therefore, the high frequency band may be set to include, for example, a frequency band of 10 Hz or higher.

Next, in step S42, the ECU 70 determines that the index value Xh indicating the magnitude of the high frequency component fh is greater than the threshold value TH1 and the index values Xm and Xl indicating the respective magnitudes of the medium frequency component fm and the low frequency component fl. is equal to or less than the threshold TH2. A specific example of these index values Xh, Xm, and Xl is the signal strength of each frequency component fh, fm, and fl. Note that the threshold TH1 and the threshold TH2 may be the same or different.

If only the index value Xh of the high frequency component fh is large in step S42 (Xh>TH1, Xm≤TH2, and Xl≤TH2), the process proceeds to step S43. In step S43, the ECU 70 determines that the vehicle 1 is traveling so as to continuously use the unsprung displacement Zu located at the boundary of the step S (step S34; Yes).

On the other hand, if the determination result in step S42 is negative, the ECU 70 determines in step S44 that the vehicle 1 is not traveling so as to continuously use the unsprung displacement Zu located at the boundary of the step S. Determine (step S34; No).

In FIG. 11, when the determination result of step S34 is negative, the process proceeds to step S35. In step S35, the ECU 70 acquires the unsprung displacement Zu at the predicted passing position Pf acquired in step S32 from the front road surface data acquired in step S33. Then, the ECU 70 calculates the target control force Fc_t of the actuator 3A of the suspension 3 based on the acquired unsprung displacement Zu. Thus, when the determination result of step S34 is negative, the filtering process PR3 in step S36, which will be described later, is not executed.

On the other hand, if the determination result of step S34 is affirmative, the process proceeds to step S36. In step S36, the ECU 70 executes a filtering process PR3 that applies a low-pass filter (LPF) to the forward road surface data (data of the unsprung displacement Zu on the forward road surface) acquired in step S33. The cutoff frequency of this LPF is set to attenuate the above-described high frequency component fh, and is, for example, 10 Hz. In addition, for example, in an example in which some kind of LPF is used as a preliminary filtering process when acquiring data of the unsprung mass displacement Zu for generating the unsprung mass displacement map 200, the filtering process PR3 of this step S36 causes the LPF will be added.

When the filtering process PR3 is applied to the forward road surface data, the phase of the forward road surface data is delayed. This phase delay increases as the time constant determined according to the applied LPF increases. Therefore, in step S37, the ECU 70 increases the preview time tp so as to cancel the phase delay of the forward road surface data according to the time constant of the LPF applied in the filtering process PR3. Specifically, the preview time tp is modified to be longer by the time constant of the applied LPF. Therefore, the preview time tp is corrected to be longer as the time constant is larger.

Next, in step S38, the ECU 70 calculates a target control force Fc_t for the actuator 3A of the suspension 3 based on the forward road surface data after the filtering process PR3. Specifically, the ECU 70 extracts the unsprung displacement Zu at the predicted passing position Pf' after the correction according to the preview time tp' after the correction by the process of step S37 from the forward road surface data after the filtering process PR3. get. Then, the ECU 70 calculates the target control force Fc_t based on the acquired unsprung displacement Zu.

Next, in step S39, the ECU 70 transmits a control command including the target control force Fc_t calculated in step S35 or S38 to the actuator 3A. The processing of steps S38 and S39 corresponds to an example of "control processing PR4".

4-3. Effect As described above, according to the present embodiment, it is assumed that the vehicle 1 is traveling so as to continuously use the unsprung displacement Zu located at the boundary of the step S existing on the unsprung displacement map 200 . If so, filtering processing PR3 is executed to apply a low-pass filter to forward road surface data used as a basis for preview damping control. As a result, oscillation of the target control force Fc_t (required control amount) caused by the influence of the step S can be suppressed. As a result, it is possible to prevent the damping effect of the preview damping control from deteriorating due to the influence of the step S. In addition, occurrence of active vibration of the sprung structure 5 (vehicle body) due to the influence of the step S can be suppressed. This leads to an improvement in ride comfort performance of the vehicle 1 .

Further, according to this embodiment, when the filtering process PR3 is performed, the preview time tp is increased so as to cancel out the phase delay of the forward road surface data according to the applied LPF time constant. As a result, the phase of the front road surface data, which is the basis for calculating the target control force Fc_t (requested control amount) of the actuator 3A of the suspension 3, and the control force Fc corresponding to the target control force Fc_t based on the front road surface data are applied to the actuator 3A. can be suppressed from occurring due to the addition of the LPF. As a result, it is possible to suppress deterioration in ride comfort performance due to the phase shift.

4-4. Modified Example of Filtering Process PR3 In the example of the filtering process PR3 in step S36 described above, an LPF with uniform intensity is applied regardless of the index value Xh indicating the magnitude of the high frequency component fh. However, if the intensity (smoothing degree) of the LPF becomes stronger than necessary, the performance of preview damping control may be impaired.

Therefore, the ECU 70 may change the intensity of the LPF according to the index value Xh. Specifically, the ECU 70 may increase the intensity of the LPF when the index value Xh is large compared to when the index value Xh is small. This makes it possible to appropriately change the strength of the LPF according to the index value Xh that correlates with the magnitude of "vibration of read data". That is, the more the high-frequency components included in the forward road surface data, the more the high-frequency components can be attenuated using an LPF with a higher intensity.

The index value Xh used to change the intensity of the LPF may be a value indicating the magnitude of the high frequency component fh of the front road surface data or a value correlated thereto. That is, the index value Xh is, for example, a value (e.g., signal strength) that indicates the magnitude of the high frequency component of the target control force Fc_t (required control amount) instead of a value that indicates the magnitude of the high frequency component fh such as signal strength. It can be. Further, if the high frequency component of the target control force Fc_t (required control amount) is large due to the influence of the high frequency component fh of the front road surface data, active vibration may occur in the sprung structure 5 (vehicle body). Therefore, another example of the index value Xh is a value indicating the magnitude of the active vibration of the sprung structure 5 (for example, at least one of the sprung displacement Zs, the sprung velocity Zs', and the sprung acceleration Zs''). A value indicating the magnitude of one high frequency component) may be used.

FIGS. 13A and 13B are diagrams for explaining specific examples 1 and 2, respectively, of changing the strength of the LPF according to the magnitude of the index value Xh.

(Specific example 1)
First, as shown in FIG. 13A, in the filtering process PR3, the ECU 70 applies the same LPF to the front road surface data when the index value Xh is large compared to when the index value Xh is small. The number of applications may be increased.

(Specific example 2)
Next, the vertical axis of FIG. 13(B) is a level value LV for numerically representing the intensity level of the LPF. The level value LV is defined by a positive number of 1 or more. More specifically, when the LPF application count is 1, the level value LV is 1. This is the same when the number of times of application is 2 or more.

Here, in the method of intermittently switching the number of times of application of the LPF to 0, 1, and 2 according to the index value Xh as in the example shown in FIG. Force Fc_t (required control amount) may change suddenly.

Therefore, as shown in FIG. 13B, in the filtering process PR3, the ECU 70 adjusts the position between the adjacent natural numbers (1, 2, 3, etc.) and the adjacent natural numbers as the index value Xh increases. The level value LV may be increased continuously using increasing decimals (such as 1.1, 1.2, and 1.3). According to this specific example 2, when increasing the level value LV as the index value Xh increases, the level value LV is not changed from 1 to 2, but is changed to 1.6, for example.

The continuous change of the LPF intensity (level value LV) as shown in FIG. 13B can be performed using, for example, the technique shown in FIG. 14 below. FIG. 14 is a block diagram showing processing for continuously changing the strength of the LPF according to the index value Xh. This processing is executed by the ECU 70 .

FIG. 14 shows a low-pass filter unit (LPF unit) 300 including six LPFs 302 as an example. Forward road surface data (see step S33) is input to the LPF unit 300 . The LPF unit 300 includes first to third signal lines 304, 306, and 308 to which forward road surface data are input in parallel.

One LPF 302 is arranged on the first signal line 304 . Two LPFs 302 are arranged in series on the second signal line 306 . Three LPFs 302 are arranged in series on the third signal line 308 .

The forward road surface data after passing through one LPF 302 arranged on the first signal line 304 is output from the first signal line 304 after being multiplied by the ratio R1. The front road surface data after sequentially passing through the two LPFs 302 arranged on the second signal line 306 is output from the second signal line 306 after being multiplied by the ratio R2. The forward road surface data after sequentially passing through the three LPFs 308 arranged on the third signal line 308 is output from the second signal line 308 after being multiplied by the ratio R3.

The respective outputs from the first to third signal lines 304 , 306 and 308 are added together to form the final output from the LPF unit 300 . This final output corresponds to forward road surface data after filtering processing PR3 by LPF unit 300, and is used as a basis for calculating target control force Fc_t (required control amount).

Each of the ratios R1, R2, and R3 is a value greater than or equal to 0 and less than 1, and their sum is 1. The ratios R1, R2, and R3 are set to the index value Xh so as to achieve the desired level value LV (that is, the intensity of the LPF of the LPF unit 300 as a whole) within the range of 1 or more positive numbers including decimals. changed accordingly.

Specifically, as illustrated in FIG. 13B, the index value Xh and the level value LV are associated in advance. For example, when the level value LV corresponding to the index value Xh is 1, the ratios R1, R2 and R3 are set to 1, 0 and 0 respectively. If the level value LV is 1.5, the ratios R1, R2 and R3 are set to 0.5, 0.5 and 0 respectively. If the level value LV is 1.6, the ratios R1, R2 and R3 are set to 0.4, 0.6 and 0 respectively. If the level value LV is 2.5, the ratios R1, R2 and R3 are set to 0.2, 0.4 and 0.5 respectively.

As described above, according to the LPF unit 300, by changing the ratios R1 to R3 according to the index value Xh, the level value LV (intensity) can be changed continuously.

According to Specific Example 2, by limiting the change rate of the level value LV with respect to the index value Xh (that is, the slope of the straight line shown in FIG. 13B) to a predetermined value or less (rate limit), the change in the index value Xh It is possible to suppress a sudden change in the required control amount due to a change in the strength of the LPF (level value LV) associated with the change.

Additionally, the time constant of the entire LPF unit 300 can be calculated, for example, based on the time constants of the individual LPFs 302 and the ratios R1, R2, and R3. Therefore, when using the second example, the ECU 70 may increase the preview time tp by the time constant of the LPF unit 300 in step S37 (see FIG. 11).

4-5. Modified Example of Determination Process PR2 As the determination process PR2, instead of the determination method A (see FIG. 12), for example, the following determination method B may be used. 15 and 16 are flow charts showing an example of the process of the boundary determination method B of the step S. FIG.

First, the processing of the flowchart shown in FIG. 15 is executed by the map management system 100 (processor 120) for each of the data storage positions (road surface section M) having data on the unsprung displacement Zu in the unsprung displacement map 200. be done.

In step S51, the processor 120 performs edge detection processing. In the edge detection process, the data storage position where the difference in unsprung displacement Zu (road surface displacement related value) between adjacent data storage positions on the unsprung displacement map 200 (road surface data map) is equal to or greater than a threshold value is detected. This is the process of identifying the edge position of the map 200 . Such edge detection processing can be performed using, for example, a known image processing technique.

At the boundary of the step S existing on the unsprung displacement map 200, the difference in the unsprung displacement Zu between adjacent data storage positions becomes large. Therefore, it can be determined that the data storage position specified as the edge position by the edge detection process is positioned at the boundary of the step S. In addition, according to the edge detection process, the road surface section M (data storage position) specified as the boundary in FIG. 10 is specified as the edge position.

Next, in step S52, the processor 120 executes processing for associating the edge presence/absence information with the data storage position targeted for the edge detection processing in step S51. The edge presence/absence information is information indicating whether or not the data storage position is an edge position. A specific example of edge presence/absence information is, for example, a flag F that is turned on when the data storage position is an edge position and turned off when the data storage position is not an edge position.

According to the process of step S52, the data storage position specified as the edge position by the edge detection process is associated with information indicating that it is an edge position (for example, flag F set to ON) as the edge presence/absence information. stored. Accordingly, when the ECU 70 refers to the unsprung displacement Zu at the data storage position while the vehicle 1 is running, the ECU 70 can recognize that the data storage position is the edge position. On the other hand, if the data storage position to be subjected to the edge detection process in step S51 is not specified as an edge position, the data storage position contains information indicating that it is not an edge position as edge presence/absence information. The set flag F) is associated and stored.

Next, the processing of the flowchart shown in FIG. 16 is executed in parallel with the processing of the flowchart shown in FIG. 11 by the ECU 70 (processor 71) of the vehicle 1 while the vehicle 1 is running.

In step S61, the ECU 70 stores the data storage position corresponding to the unsprung displacement Zu used for calculating the required control amount (target control force Fc_t) at the current time step (that is, the data storage position corresponding to the predicted passing position Pf). is ON or not.

As a result, if the flag F is not turned on in step S61 (that is, if the data storage position corresponding to the predicted passing position Pf at the current time step is not an edge position), the process proceeds to step S62. In step S62, the ECU 70 clears the count value of the counter CT. This counter CT is a counter for counting the number of times the flag F of the data storage position corresponding to the predicted passing position Pf is turned on.

On the other hand, if the flag F is ON in step S61 (that is, if the data storage position corresponding to the predicted passing position Pf at the current time step is the edge position), the process proceeds to step S63. In step S63, the ECU 70 increments the count value of the counter CT by one. According to the processing of steps S61 to S63, the count value is counted up only when the flag F is continuously turned on in consecutive time steps. Therefore, the count value corresponds to the number of consecutive detections that the data storage position arriving at each time step is the edge position.

Next, in step S64, the ECU 70 determines whether or not the count value of the counter CT is equal to or greater than the threshold. As a result, if the count value is equal to or greater than the threshold value, that is, if the ECU 70 continuously detects that the data storage position is the edge position for a predetermined number of times or more, the process proceeds to step S65. In step S65, the ECU 70 determines that the vehicle 1 is traveling so as to continuously use the unsprung displacement Zu located at the boundary of the step S (step S34; Yes).

On the other hand, if the determination result of step S64 is negative, or after step S62 is executed, the process proceeds to step S66. In step S66, the ECU 70 determines that the vehicle 1 is not traveling so as to continuously use the unsprung displacement Zu located at the boundary of the step S (step S34; No).

As described above, according to the processing of the flowchart shown in FIG. 16, when it is detected that the data storage position is the edge position continuously for a predetermined number of times or more, the unsprung displacement Zu at the boundary of the step S is It can be determined that the vehicle 1 is running for continuous use. This is because when the vehicle 1 (wheels 2) continuously passes the edge position many times, it can be estimated that there is a high possibility that the above-described "vibration of read data" has occurred.

In addition, according to the process of step S64, even if the data storage position is detected to be an edge position, if the detection is intermittent (that is, if the detection is not continuous for a predetermined number of times or more), , the determination result of step S34 is not affirmative. The reason for this is as follows. That is, when the vehicle 1 travels across a rut, for example, the vehicle 1 temporarily (intermittently) uses the unsprung displacement Zu at the data storage position, which is the edge position, when traversing the rut. run like this. However, when the vehicle 1 traverses a rut, unlike when the vehicle 1 travels along a rut, the vehicle 1 (wheels 2) does not continuously pass the edge position multiple times. That is, by performing the determination using the counter CT in step S64, it is possible to determine whether the vehicle 1 is traveling along the rut while distinguishing the case where the vehicle 1 is traveling across the rut. It becomes possible. In other words, when the vehicle 1 is traveling across ruts, it is possible to avoid erroneously determining that the determination result in step S34 is affirmative. As a result, when the vehicle 1 is traveling across ruts, it is possible to avoid a decrease in the damping effect of the preview damping control due to the execution of the filtering process PR3.

1 vehicle 2 wheel 3 suspension 3A suspension actuator 4 unsprung structure 5 sprung structure 10 vehicle control system 20 vehicle state sensor 40 position sensor 50 communication device 60 travel device 70 electronic control unit 100 map management system 110 communication device 120 processor 130 storage device 300 low-pass filter unit (LPF unit)
302 Low Pass Filter (LPF)

Claims (9)

an actuator that controls the suspension stroke of the wheel to be controlled;
an electronic control unit that performs preview damping control that reduces vibration of the sprung structure of the vehicle by controlling the actuator;
A vehicle suspension control device comprising:
The electronic control unit is
The road surface on the front road including the predicted passing position of the control target wheel after the preview time from the current time is obtained from the road surface data map in which the road surface displacement related value related to the vertical displacement of the road surface is associated with the data storage position and mapped. Acquisition processing for acquiring forward road surface data, which is displacement-related value data;
Determination processing for determining whether the vehicle is traveling so as to continuously use the road surface displacement-related value located at a boundary between steps of the road surface displacement-related value existing on the front road surface data;
a filtering process of applying a low-pass filter to the forward road surface data when the determination result of the determination process is affirmative;
a control process of executing the preview damping control based on the forward road surface data after the filtering process when the determination result of the determination process is positive;
A suspension control device for a vehicle, characterized by: In the filtering process, the electronic control unit increases the strength of the low-pass filter when the index value indicating the magnitude of the high-frequency component of the forward road surface data is large compared to when the index value is small. The vehicle suspension control device according to claim 1, characterized by: In the filtering process, the electronic control unit increases the number of times the low-pass filter is applied to the forward road surface data when the index value is large compared to when the index value is small. 3. The vehicle suspension control device according to claim 2. When the level value of the intensity of the low-pass filter is defined as a positive number of 1 or more, in the filtering process, the electronic control unit increases the index value between adjacent natural numbers. 4. The suspension control system for a vehicle according to claim 2, wherein the level value is continuously increased while using a decimal number located at . When the determination result of the determination process is affirmative, the electronic control unit adjusts the preview time so as to cancel the phase delay of the forward road surface data according to the time constant of the low-pass filter applied in the filtering process. 5. The suspension control device for a vehicle according to claim 1, characterized in that it increases . In the determination process, the electronic control unit determines that a first index value indicating the magnitude of the high-frequency component of the front road surface data is greater than a threshold and indicates the magnitude of the frequency component on the lower side than the high-frequency component. When the second index value is equal to or less than a threshold value, it is determined that the vehicle is traveling so as to continuously use the road surface displacement related value located at the boundary. The vehicle suspension control device according to any one of the above. A vehicle suspension control device according to any one of claims 1 to 5,
The vehicle control system, wherein the vehicle suspension control device receives the road surface data map generated by the map management system from a map management system that generates the road surface data map. The map management system includes:
In the process executed for each of the data storage positions, the road surface data storage positions are selected from adjacent data storage positions on the road surface data map at which the difference in the road surface displacement-related value is equal to or greater than a threshold value. an edge detection process that identifies edge locations in the data map;
a process executed for each of the data storage locations, the process associating edge presence/absence information indicating whether the data storage location is the edge location with the data storage location;
and run
In the determination process, if the electronic control unit continuously detects that the data storage position corresponding to the predicted passing position is the edge position for a predetermined number of times or more, the road surface displacement related value located at the boundary 8. The vehicle control system of claim 7, wherein the vehicle determines that the vehicle is traveling to continuously use . A vehicle suspension control method for executing preview damping control for reducing vibration of a sprung structure of a vehicle by controlling an actuator that controls a suspension stroke of a wheel to be controlled, comprising:
The road surface on the front road including the predicted passing position of the control target wheel after the preview time from the current time is obtained from the road surface data map in which the road surface displacement related value related to the vertical displacement of the road surface is associated with the data storage position and mapped. Acquisition processing for acquiring forward road surface data, which is displacement-related value data;
Determination processing for determining whether the vehicle is traveling so as to continuously use the road surface displacement-related value located at a boundary between steps of the road surface displacement-related value existing on the front road surface data;
a filtering process of applying a low-pass filter to the forward road surface data when the determination result of the determination process is affirmative;
a control process of executing the preview damping control based on the forward road surface data after the filtering process when the determination result of the determination process is positive;
A suspension control method for a vehicle, comprising:

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