Method for estimating vertical acceleration, vehicle control method, and vertical acceleration estimation system

Abstract

This improves the estimation accuracy when estimating vertical acceleration without using sensors to detect the vertical acceleration occurring in a vehicle. [Solution] In the vertical acceleration estimation method, the vehicle's driving position and speed are detected (S2, S3), the vehicle's wheel speed fluctuations are calculated (S4), and information on the combination of wheel speed fluctuations and vertical acceleration corresponding to the detected vehicle's driving position and speed, as well as the vehicle's vehicle type, is read from a database that stores vehicle type information, information on combinations of vertical acceleration and wheel speed fluctuations occurring in vehicles of the vehicle type information, and information on the driving position and speed at which the vertical acceleration and wheel speed fluctuations occur in the vehicle (S5, S6). Based on the information on combinations of wheel speed fluctuations and vertical acceleration read from the database and the calculated vehicle's wheel speed fluctuations, the vertical acceleration occurring in the vehicle is estimated (S7~S11).

Description

Technical Field

[0001] The present invention relates to a vertical acceleration estimation method, a vehicle control method, and a vertical acceleration estimation system.

Background Art

[0002] The information processing system described in Patent Document 1 connects a vehicle including a sensor that observes floor acceleration, yaw rate, roll rate, and pitch rate to an information processing apparatus via a network, and changes control parameters of a variable suspension damping force mechanism based on observation results of observation information corresponding to a plurality of vehicle behavior observation results.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] When a sensor for detecting vehicle behavior is mounted on a vehicle to be controlled as in the system described in Patent Document 1, there is a problem that the manufacturing cost of the vehicle increases due to the addition of the sensor. An object of the present invention is to improve estimation accuracy when estimating vertical acceleration without using a sensor for detecting vertical acceleration generated in a vehicle.

Means for Solving the Problem

[0005] In one aspect of the present invention, a method for estimating vertical acceleration involves detecting the vehicle's driving position and speed, calculating the vehicle's wheel speed fluctuations, and reading information on the combination of wheel speed fluctuations and vertical acceleration corresponding to the vehicle's driving position and speed, as well as the vehicle's type, from a database that stores vehicle type information, information on combinations of vertical acceleration and wheel speed fluctuations occurring in vehicles of the vehicle type information, and information on the vehicle's driving position and speed at which the vertical acceleration and wheel speed fluctuations occur. Based on the information on the combination of wheel speed fluctuations and vertical acceleration read from the database and the calculated vehicle's wheel speed fluctuations, the method estimates the vertical acceleration occurring in the vehicle. [Effects of the Invention]

[0006] According to the present invention, the estimation accuracy when estimating vertical acceleration without using a sensor to detect vertical acceleration generated in a vehicle can be improved. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram of an example of a vertical acceleration estimation system according to an embodiment. [Figure 2] This table shows an example of a vertical acceleration database. [Figure 3] (a) is an explanatory diagram of the method for estimating vertical acceleration, and (b) is a schematic diagram of a model representing the suspension. [Figure 4] This is a block diagram of an example of the functional configuration of the vertical acceleration estimation system according to the embodiment. [Figure 5] (a) and (b) are explanatory diagrams illustrating an example of a method for estimating vertical acceleration based on a vertical acceleration database. [Figure 6] This is a flowchart of an example of a vehicle control method according to the embodiment. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. Note that the drawings are schematic and may differ from actual ones. Furthermore, the embodiments of the present invention described below are illustrative examples of devices and methods for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited to the structure, arrangement, etc., of the components described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims described in the patent claims.

[0009] (composition) Figure 1 is a schematic diagram of an example of a vertical acceleration estimation system according to an embodiment. The vertical acceleration estimation system 1 comprises a vehicle control device 20 mounted on the vehicle 2 whose vertical acceleration is to be estimated, and a server device 3, and estimates the vertical acceleration (hereinafter sometimes simply referred to as "vertical acceleration") generated in the sprung mass structure of the vehicle 2.

[0010] The vehicle control device 20 works in cooperation with the server device 3 to estimate the vertical acceleration generated in the vehicle 2, and controls the braking force of the vehicle 2 by driving the drive force source 26 and / or braking device 27 based on the estimated vertical acceleration, thereby suppressing the vertical acceleration of the vehicle 2. The vehicle control device 20 includes a positioning device 21, a wheel speed sensor 22, an acceleration sensor 23, a communication device 24, a controller 25, a drive power source 26, and a braking device 27.

[0011] The positioning device 21 measures the current position of the vehicle 2. The positioning device 21 includes, for example, a Global Navigation Satellite System (GNSS) receiver. The GNSS receiver is, for example, a Global Positioning System (GPS) receiver, and measures the current position of the vehicle 2 by receiving radio waves from multiple navigation satellites. The wheel speed sensor 22 detects the wheel speeds ωFR, ωFL, ωRR, and ωRL of the vehicle 2's right front wheel WFR, left front wheel WFL, right rear wheel WRR, and left rear wheel WRL, respectively.

[0012] In the following explanation, the right front wheel WFR, left front wheel WFL, right rear wheel WRR, and left rear wheel WRL will be referred to as "wheel W," and the wheel speeds ωFR, ωFL, ωRR, and ωRL will be collectively referred to as "wheel speed ω." The acceleration sensor 23 detects the longitudinal acceleration a generated in the vehicle 2. x Detects. The communication device 24 provides a communication function between the vehicle 2 and an external device. The communication method used by the communication device 24 may include, for example, wireless communication over a public mobile communication network, satellite communication, vehicle-to-infrastructure communication, etc. The vehicle 2 sends and receives data to and from the server device 3 using the communication device 24.

[0013] The controller 25 is an electronic control unit (ECU) that estimates the vertical acceleration generated in the vehicle 2 and controls the braking and driving forces of the vehicle 2 according to the estimation result. The controller 25 includes, for example, a computer that includes a processor 25a and peripheral components such as a memory device 25b. The processor 25a may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit).

[0014] The storage device 25b may include any of semiconductor storage devices, magnetic storage devices, or optical storage devices. The storage device 25b may include memory such as ROM (Read Only Memory) and RAM (Random Access Memory) used as main memory, as well as registers and cache memory.

[0015] The driving force source 26 is an electric motor, an engine, or a combination thereof that generates the driving force to propel the vehicle 2. In other words, the vehicle 2 may be an electric vehicle, a vehicle powered by a gasoline engine, or a hybrid vehicle powered by both an engine and a motor. The braking device 27 is a device that generates braking force on the wheels WFR, WFL, WRR, and WRL of the vehicle 2 by frictional braking force.

[0016] The server device 3 includes a computer comprising a processor 30, peripheral components such as a storage device 31, a communication device 32, and a vertical acceleration database (hereinafter sometimes referred to as "vertical acceleration DB") 33. The processor 30 may be, for example, a CPU or an MPU. The storage device 31 may include any of semiconductor storage devices, magnetic storage devices, and optical storage devices. The storage device 31 may include memory such as ROM and RAM used as main memory, as well as registers and cache memory.

[0017] The communication device 32 provides communication functionality between the server device 3 and external devices. The communication method used by the communication device 32 may include, for example, wireless communication via a public mobile communication network, satellite communication, or vehicle-to-infrastructure communication with a vehicle. The server device 3 transmits and receives data with its own vehicle 2 using the communication device 32. The Vertical Acceleration DB33 is a database that stores information on the vertical acceleration that occurs when various types of vehicles travel at various locations.

[0018] Figure 2 is a table showing an example of the vertical acceleration DB33. The vertical acceleration DB33 stores information on combinations of vertical acceleration and wheel speed fluctuations obtained by actually detecting the vertical acceleration and wheel speed fluctuations occurring in a moving vehicle, vehicle type information (e.g., VIN: Vehicle Identify Number) representing the type of vehicle, and information on the vehicle's position (e.g., latitude and longitude) and speed when the vertical acceleration and wheel speed fluctuations occurred, all linked together.

[0019] The information of combinations of vertical acceleration and wheel speed fluctuations stored in the vertical acceleration DB33 may be information of combinations of vertical acceleration and wheel speed fluctuations that occurred in a vehicle whose vehicle characteristics are known. In addition to the above information (vertical acceleration, wheel speed fluctuations, vehicle type information, driving position, vehicle speed), the vertical acceleration DB33 may also store information of known vehicle characteristics. As vehicle characteristics, for example, information such as the mass of the sprung mass, the spring constant of the wheel tires, the spring constant of the suspension, and the characteristic coefficient of the suspension may be stored.

[0020] As shown in Figure 2, the vertical acceleration DB33 stores information on combinations of vertical acceleration and wheel speed fluctuations that occurred in multiple vehicles with different vehicle characteristics, even if they are of the same model. For example, the data in the first to third rows of the table in Figure 2 contains information on combinations of vertical acceleration and wheel speed fluctuations that occurred in vehicles of the same type (vehicle type A). However, the vehicle in the first row and the vehicle in the second row have different sprung mass and suspension characteristic coefficients, and the vehicle in the first row and the vehicle in the third row have different tire spring constants and suspension characteristic coefficients. The vehicle in the second row and the vehicle in the third row have different sprung mass, tire spring constants, and suspension characteristic coefficients.

[0021] Next, the estimation method used by the vertical acceleration estimation system 1 of this embodiment to estimate the vertical acceleration occurring in the vehicle 2 will be described. It is known that when a vehicle experiences vertical acceleration and moves in the vertical direction, the suspension geometry causes the wheels to move in the longitudinal direction in conjunction with the vertical movement of the wheels.

[0022] Figure 3(a) is an explanatory diagram of the longitudinal motion linked to the vertical motion of the wheels. The dashed lines W1 and rf1 show the positions of the wheels and the road surface before the vertical motion, and the solid lines W2 and rf2 show the positions of the wheels and the road surface after the vertical motion. When the unsprung mass vibrates due to road surface irregularities, a wind-up occurs around the suspension rotation center C, as shown in Figure 3(a).

[0023] As the wheel is wound up, the wheel center is displaced by ΔZ and ΔX in the vertical and longitudinal directions, respectively, and as a result, the wheel rotates by (ΔX / tire radius). Therefore, the second derivative of the displacement ΔX, i.e., the first derivative of the peripheral speed of the wheel W (wheel speed ω × tire radius), is converted by a geometry transformation coefficient Tan, which is determined according to the suspension geometry. -1 By multiplying by φ, the vertical acceleration component can be detected. This geometry transformation coefficient Tan -1 φ can be set, for example, by the design value or experimentation of the vehicle 2.

[0024] The actual wheel speed includes the speed component of the vehicle itself. For this reason, the longitudinal acceleration a of the body of the host vehicle 2 is obtained from the differential value of the circumferential speed of the wheel W (wheel speed ω × tire dynamic radius) x subtracted, and the subtraction result is multiplied by the geometry conversion coefficient Tan -1 φ to calculate an estimated value of the vertical acceleration generated in the host vehicle 2. In the following description, the longitudinal acceleration a obtained from the differential value of the circumferential speed of the wheel W (wheel speed ω × tire dynamic radius) x after subtraction may be referred to as "wheel speed fluctuation Δω". Further, the estimated value of vertical acceleration calculated by multiplying wheel speed fluctuation Δω by the geometry conversion coefficient Tan -1 φ may be referred to as "estimated vertical acceleration a zv ". As described above, the vehicle control device 20 can estimate vertical acceleration generated in the host vehicle 2 without using a sensor for detecting the vertical acceleration.

[0025] On the other hand, the vehicle characteristics when the host vehicle 2 actually travels may deviate from the vehicle characteristics assumed as the premise of the geometry conversion coefficient Tan -1 φ. For example, the vehicle characteristics of the host vehicle 2 fluctuate due to differences in the number of occupants or loaded weight, and aging degradation of the chassis. If the vehicle characteristics of the host vehicle 2 differ from the vehicle characteristics assumed as the premise of the geometry conversion coefficient Tan -1 φ, the estimated vertical acceleration a estimated from wheel speed fluctuation Δω zv deviates from the vertical acceleration actually generated in the host vehicle 2. The reason will be described with reference to Fig. 3(b).

[0026] Fig. 3(b) is a schematic diagram of a model showing a suspension. The equation of motion for the sprung structure in the model can be written as the following formulas (1) and (2). In formulas (1) and (2), m1 is the unsprung mass, k1 is the unsprung stiffness, m2 is the sprung mass, k2 is the spring stiffness, c is the suspension damping constant, z0 is the vertical displacement of disturbance, z1 is the unsprung vertical displacement, and z2 is the sprung vertical displacement.

[0027]

number

[0028] From equations (1) and (2) above, the acceleration of the vertical displacement on the spring (d) in the following equation (3) is obtained. 2 z2 / dt 2 ) can be derived. Equation (3) can be approximated by the following equation (4). ω0 represents the reference wheel speed obtained by removing various disturbances from the wheel speed of each wheel, ω1 represents the wheel speed detected by the sensor, and r0 represents the radius of motion of the tire.

[0029]

number

[0030] The acceleration of the sprung displacement shown in equation (4) above (d 2 z2 / dt 2 The term includes a term ((ω0-ω1) / ω1) corresponding to the wheel speed fluctuation Δω, and a term (-2×k1×r0 / m2) that varies depending on the vehicle characteristics. Therefore, when estimating the vertical acceleration of the vehicle's sprung mass based on the wheel speed fluctuation Δω, it is affected by differences in the number of occupants, load weight, and changes in vehicle characteristics due to aging.

[0031] Therefore, the vertical acceleration estimation system 1 of this embodiment refers to the vertical acceleration DB 33 of the server device 3 and estimates the vertical acceleration occurring in the vehicle 2 based on information on the vertical acceleration that actually occurred in a vehicle of the same type as the vehicle 2. As shown in Figure 2, vertical acceleration DB33, even when vehicles of the same type (vehicle type A) travel at the same location (latitude xx, longitude yy) and the same speed (80 km / h), the combination of wheel speed fluctuations and vertical acceleration that occur in the vehicle differs depending on the vehicle characteristics.

[0032] Here, when different vehicles of the same make and model travel under the same road surface input conditions (driving position, vehicle speed), the relationship between wheel speed fluctuations and vertical acceleration changes solely depending on the vehicle characteristics. If the resulting wheel speed fluctuations are the same or similar to each other, it can be inferred that the vehicle characteristics of these vehicles are the same or similar to each other. Therefore, the vertical acceleration estimation system 1 detects the driving position and speed of the vehicle 2, calculates the wheel speed fluctuation of the vehicle 2, and reads information from the vertical acceleration DB 33 regarding the driving position and speed of the vehicle 2, as well as the combination of wheel speed fluctuation and vertical acceleration corresponding to the vehicle type of the vehicle 2.

[0033] The vertical acceleration estimation system 1 estimates the vertical acceleration occurring in the vehicle 2 based on the information of the combination of wheel speed fluctuations and vertical acceleration read from the vertical acceleration DB 33, and the wheel speed fluctuations of the vehicle 2. This allows the vertical acceleration estimation system 1 to improve the estimation accuracy when estimating vertical acceleration without using sensors to detect vertical acceleration occurring in the vehicle 2.

[0034] Next, an example of the functional configuration of the vertical acceleration estimation system of the embodiment will be described with reference to Figure 4. The vehicle control device 20 mounted on the vehicle 2 includes a vehicle speed calculation unit 40, a vertical acceleration estimation unit 41, a vertical acceleration correction unit 42, a vehicle control unit 43, a drive force source 26, and a braking device 27. The server device 3 includes the aforementioned vertical acceleration DB 33, a data reading unit 50, and a correction coefficient calculation unit 51.

[0035] The functions of the vehicle speed calculation unit 40, the vertical acceleration estimation unit 41, the vertical acceleration correction unit 42, and the vehicle control unit 43 of the vehicle control device 20 are realized, for example, by the processor 25a of the controller 25 executing a computer program stored in the storage device 25b. The functions of the data reading unit 50 and the correction coefficient calculation unit 51 of the server device 3 are realized, for example, by the processor 30 executing a computer program stored in the storage device 31.

[0036] The vehicle speed calculation unit 40 calculates the vehicle speed V of the vehicle 2 based on the wheel speeds ω of the vehicle's wheels W. For example, the vehicle speed calculation unit 40 may calculate the vehicle speed V as the average of the wheel speeds ωFL, ωFR, ωRL, and ωRR. The vertical acceleration estimation unit 41 uses the wheel speed ω of the vehicle's wheels W and the longitudinal acceleration a of the vehicle's wheels 2 detected by the acceleration sensor 23. x Based on this, the wheel speed fluctuation Δω occurs in the wheels of vehicle 2. v We estimate this.

[0037] For example, the vertical acceleration estimation unit 41 estimates the wheel speed fluctuation Δω that occurs in the front wheels WFR and WFL of the vehicle 2. v It is possible to estimate the vertical acceleration a. For example, the vertical acceleration estimation unit 41 calculates the front wheel circumferential speed (ωFL+ωFR)×r0 / 2 by multiplying the average of the front wheel speeds ωFL and ωFR of the vehicle 2 by the tire radius r0, and then calculates the longitudinal acceleration a of the vehicle body from the derivative of the calculated front wheel circumferential speed. x By subtracting the wheel speed fluctuation Δω v It is reasonable to estimate this.

[0038] The vertical acceleration estimation unit 41 estimates the wheel speed fluctuation Δω v Then, the pre-set geometry transformation coefficient Tan for vehicle 2 -1 By multiplying by φ, we obtain the estimated vertical acceleration a, which is the estimated value of the vertical acceleration that occurred in the vehicle 2. zv Calculate the geometry transformation coefficient Tan -1 φ and estimated vertical acceleration a zv This is an example of the "vehicle model" and "second vertical acceleration" described in the claims. The communication device 24 (see Figure 1) of the vehicle control device 20 receives vehicle type information of the vehicle 2, the current driving position of the vehicle 2 detected by the positioning device 21, the current vehicle speed V of the vehicle 2, and the wheel speed fluctuation Δω v And, estimated vertical acceleration a zv Send this to server device 3.

[0039] The communication device 32 of the server device 3 (see Figure 1) receives vehicle type information of its own vehicle 2, as well as its driving position, vehicle speed V, and wheel speed fluctuation Δω. v and estimated vertical acceleration a zvThe information is received from vehicle 2. The data reading unit 50 reads data from the vertical acceleration DB 33 that combines wheel speed fluctuations and vertical acceleration, associated with the vehicle type information, driving position, and vehicle speed V received from the vehicle 2.

[0040] For example, if only one combination of wheel speed fluctuation and vertical acceleration information is stored in the vertical acceleration DB33 in association with the vehicle type information, driving position and vehicle speed V received from the vehicle 2, the data reading unit 50 may read the data for that one combination of wheel speed fluctuation and vertical acceleration. If multiple combinations of wheel speed fluctuation and vertical acceleration information are stored in the vertical acceleration DB33 in association with the vehicle type information, driving position and vehicle speed V received from the vehicle 2, the data reading unit 50 may read the data for multiple combinations of wheel speed fluctuation and vertical acceleration.

[0041] The correction coefficient calculation unit 51 calculates a reference vertical acceleration a, which is estimated as the vertical acceleration occurring in the vehicle 2, based on the data of the combination of wheel speed fluctuation and vertical acceleration read from the vertical acceleration DB 33. zd Estimate the vertical acceleration a. zd This is an example of the "first vertical acceleration" described in the claims. Specifically, the correction coefficient calculation unit 51 uses the data read by the data reading unit 50 from the vertical acceleration DB 33, which is a combination of wheel speed fluctuation and vertical acceleration data, and the wheel speed fluctuation Δω received from the vehicle 2. v Based on the information, reference vertical acceleration a zd We estimate this.

[0042] For example, when the data reading unit 50 reads data for one combination of wheel speed fluctuation and vertical acceleration, the correction coefficient calculation unit 51 calculates the wheel speed fluctuation Δω received from the vehicle 2 based on the wheel speed fluctuation read by the data reading unit 50. v If the difference is less than the threshold, the data reading unit 50 reads the vertical acceleration and references the vertical acceleration a. zd It is estimated as such, and if the difference is greater than or equal to the threshold, the reference vertical acceleration a zd It is safe to conclude that it cannot be estimated.

[0043] For example, if the data reading unit 50 reads data for multiple combinations of wheel speed fluctuations and vertical acceleration, the correction coefficient calculation unit 51 calculates the wheel speed fluctuation Δω received from the vehicle 2 among the multiple wheel speed fluctuations read by the data reading unit 50. v Refer to the vertical acceleration that is most closely associated with the wheel speed fluctuation. zd It is reasonable to assume this.

[0044] Alternatively, the correction coefficient calculation unit 51 may estimate an approximate function (approximate curve or approximate straight line) of vertical acceleration with respect to wheel speed fluctuations based on multiple combinations of wheel speed fluctuations and vertical acceleration read by the data reading unit 50. Refer to Figures 5(a) and 5(b). The multiple plotted points in Figures 5(a) and 5(b) show combinations of wheel speed fluctuations and vertical acceleration when the suspension characteristic coefficient is "0.420", "0.350", and "0.462" in the vertical acceleration DB33 of Figure 2.

[0045] The correction coefficient calculation unit 51 may estimate an approximate curve LA1 or an approximate straight line LA2 of vertical acceleration with respect to wheel speed fluctuations based on multiple combinations of these wheel speed fluctuations and vertical accelerations. The correction coefficient calculation unit 51 calculates the wheel speed fluctuation Δω received from the vehicle 2 using the estimated approximation function. v Based on this, reference vertical acceleration a zd It is acceptable to estimate the wheel speed fluctuation Δω on the approximate curve LA1 or the approximate straight line LA2. v See the corresponding vertical acceleration a zd It is reasonable to assume this.

[0046] The correction coefficient calculation unit 51 calculates the estimated vertical acceleration a received from the vehicle 2. zv Reference vertical acceleration a zd The ratio of the correction coefficient K = (a zd / a zv ) is used for the calculation. The communication device 32 of the server device 3 transmits the correction coefficient K calculated by the correction coefficient calculation unit 51 to the vehicle control device 20 of the vehicle 2. The communication device 24 of the vehicle control device 20 receives the correction coefficient K transmitted from the server device 3.

[0047] The vertical acceleration correction unit 42 uses the estimated vertical acceleration a estimated by the vertical acceleration estimation unit 41. zv By correcting with the correction coefficient K, the vertical acceleration a generated in the vehicle 2 is calculated. z The vertical acceleration correction unit 42 estimates the vertical acceleration a. zv The product obtained by multiplying by the correction coefficient K is the vertical acceleration a z =(K×a zv It may also be calculated as follows: The vehicle control unit 43 receives the vertical acceleration a estimated by the vertical acceleration correction unit 42. z The braking and driving force of the vehicle 2 is controlled by driving the power source 26 and / or the braking device 27 based on this.

[0048] For example, the vehicle control unit 43 receives the vertical acceleration a estimated by the vertical acceleration correction unit 42. z When the value exceeds a threshold, braking force control by the braking device 27 may be performed. For example, the vehicle control unit 43 uses the vertical acceleration a estimated by the vertical acceleration correction unit 42. z A target braking force amount may be set based on this, and the braking device 27 may be controlled to generate a braking force corresponding to the set target braking force amount. If the driver is operating the brake pedal, the braking device 27 may be controlled to generate the larger of the braking force control amount and the braking force requested by the driver.

[0049] For example, the vehicle control unit 43 uses the vertical acceleration a estimated by the vertical acceleration correction unit 42. z When the value exceeds a predetermined threshold, a correction may be performed to increase or decrease the driving force generated by the driving force source 26. It is known that when a driving force is generated in a vehicle, the suspension geometry affects the vehicle's vertical force, thereby influencing its vertical movement. The vehicle control unit 43 may suppress vertical acceleration by applying a driving force in a direction that counteracts the vertical acceleration generated by the road surface input.

[0050] (operation) Figure 6 is a flowchart of an example of a vehicle control method according to the embodiment. In step S1, the wheel speed sensor 22 detects the wheel speed ω of the vehicle 2's wheels W. In step S2, the positioning device 21 detects the current driving position of the vehicle 2. In step S3, the vehicle speed calculation unit 40 calculates the vehicle speed V of the vehicle 2 based on the wheel speed ω of the wheels W of the vehicle 2.

[0051] In step S4, the vertical acceleration estimation unit 41 calculates the wheel speed ω and the longitudinal acceleration a of the vehicle 2. x Based on this, the wheel speed fluctuation Δω occurs in the wheels of vehicle 2. v We estimate the wheel speed fluctuation Δω. v and geometry transformation coefficient Tan -1 Estimated vertical acceleration a based on φ zv Calculate. In step S5, the communication device 24 receives the vehicle type information of the vehicle 2, the current driving position of the vehicle 2 detected by the positioning device 21, the current vehicle speed V of the vehicle 2, and the wheel speed fluctuation Δω v And, estimated vertical acceleration a zv Send this to server device 3.

[0052] In step S6, the data reading unit 50 of the server device 3 reads data from the vertical acceleration DB 33 that is a combination of wheel speed fluctuation and vertical acceleration, associated with the vehicle type information received from the vehicle 2, the driving position, and the vehicle speed V. In step S7, the correction coefficient calculation unit 51 calculates the reference vertical acceleration a based on the data of the combination of wheel speed fluctuation and vertical acceleration read from the vertical acceleration DB 33. zd Calculate.

[0053] In step S8, the correction coefficient calculation unit 51 calculates the estimated vertical acceleration a received from the vehicle 2. zv Reference vertical acceleration a zd The ratio of the correction coefficient K = (a zd / a zv ) is used for the calculation. In step S9, the communication device 32 transmits the correction coefficient K to the vehicle control device 20. In step S10, the vertical acceleration correction unit 42 uses the estimated vertical acceleration a estimated by the vertical acceleration estimation unit 41. zv By correcting with the correction coefficient K, the vertical acceleration a generated in the vehicle 2 is calculated. z We estimate this.

[0054] In step S11, the vehicle control unit 43 determines the vertical acceleration a estimated by the vertical acceleration correction unit 42. z Based on this, the target value of the braking and driving force control amount to be applied to vehicle 2 is calculated. In step S12, the vehicle control unit 43 controls the braking and driving force of the vehicle 2 by driving the drive source 26 and / or braking device 27 based on the target value calculated in step S11.

[0055] (modified version) (1) The server device 3 replaces the correction coefficient K with the reference vertical acceleration a zd The vehicle control unit 43 may transmit itself to the vehicle 2. The vehicle control unit 43 receives the reference vertical acceleration a from the server device 3. zd The braking and driving force of the vehicle 2 may be controlled by driving the drive source 26 and / or the braking device 27 based on this. In this case, the estimated vertical acceleration a in the vehicle control device 20 zv The operation may be omitted.

[0056] (2) The processor 30 of the server device 3 may perform some or all of the above processing performed by the processor 25a of the vehicle control device 20, or the processor 25a may perform some or all of the above processing performed by the processor 30. For example, the vertical acceleration estimation system 1 only needs to have a vehicle speed calculation unit 40, a vertical acceleration estimation unit 41, a vertical acceleration correction unit 42, a vehicle control unit 43, a data reading unit 50, and at least one processor (for example, either processor 25a or processor 30) that performs processing in the correction coefficient calculation unit 51.

[0057] (Effects of the embodiment) (1) In the vertical acceleration estimation method, the vehicle's driving position and speed are detected, the vehicle's wheel speed fluctuations are calculated, and information on the combination of wheel speed fluctuations and vertical acceleration corresponding to the vehicle's driving position and speed, as well as the vehicle's driving position and speed, is read from a database that stores vehicle type information, information on combinations of vertical acceleration and wheel speed fluctuations occurring in vehicles of the vehicle type information, and information on the vehicle's driving position and speed at which vertical acceleration and wheel speed fluctuations occur in the vehicle. Based on the information on combinations of wheel speed fluctuations and vertical acceleration read from the database and the calculated wheel speed fluctuations of the vehicle, the vertical acceleration occurring in the vehicle is estimated. This improves the accuracy of estimating vertical acceleration without using sensors to detect the vertical acceleration occurring in the vehicle.

[0058] (2) Based on the information of the combination of wheel speed fluctuations and vertical acceleration read from the database, a first vertical acceleration corresponding to the calculated wheel speed fluctuation of the vehicle may be calculated, and a second vertical acceleration, which is an estimated value of the vertical acceleration occurring in the vehicle, may be estimated based on a pre-set vehicle model of the vehicle and the calculated wheel speed fluctuation of the vehicle, and the ratio of the first vertical acceleration to the second vertical acceleration may be calculated as a correction coefficient, and the second vertical acceleration may be corrected with the correction coefficient. This allows for improved accuracy in the second vertical acceleration, which is estimated based on the vehicle's wheel speed fluctuations, through correction.

[0059] (3) Based on information from multiple combinations of wheel speed fluctuations and vertical acceleration read from the database, an approximate function of vertical acceleration with respect to wheel speed fluctuations may be estimated, and the vertical acceleration occurring in the vehicle may be estimated based on the approximate function and the calculated wheel speed fluctuations of the vehicle. For example, the database may store information on combinations of vertical acceleration and wheel speed fluctuations occurring for each of multiple vehicles of the same model, each with different vehicle characteristics, associated with the same vehicle model information. Based on the information on combinations of vertical acceleration and wheel speed fluctuations that occurred for each of the multiple vehicles stored associated with the same vehicle model information, an approximate function may be calculated using the information on multiple combinations of wheel speed fluctuations and vertical acceleration read from the database. This allows the vertical acceleration occurring in the vehicle to be estimated based on information from multiple combinations of wheel speed fluctuations and vertical acceleration stored in the database.

[0060] (4) In the vehicle control method, the braking and driving force of the vehicle may be controlled based on the vertical acceleration of the vehicle estimated by any of (1) to (3) above. For example, the braking force of the vehicle may be controlled based on the vertical acceleration of the vehicle estimated by any of (1) to (3) above. This makes it possible to suppress the vertical acceleration generated in the vehicle by controlling the braking force and / or driving force of the vehicle. [Explanation of symbols]

[0061] 1…Vertical acceleration estimation system, 2…Vehicle, 3…Server device, 20…Vehicle control device, 21…Positioning device, 22…Wheel speed sensor, 23…Accelerometer, 24, 32…Communication device, 25…Controller, 25a, 30…Processor, 25b, 31…Storage device, 26…Drive force source, 27…Braking device, 40…Vehicle speed calculation unit, 41…Vertical acceleration estimation unit, 42…Vertical acceleration correction unit, 43…Vehicle control unit, 50…Data reading unit, 51…Correction coefficient calculation unit, WFL…Left front wheel, WFL…Front wheel, WFR…Right front wheel, WRL…Left rear wheel, WRR…Right rear wheel

Claims

1. The vehicle's position and speed are detected, The wheel speed fluctuation of the aforementioned vehicle is calculated, From a database that stores vehicle type information, information on combinations of vertical acceleration and wheel speed fluctuations occurring in a vehicle of the vehicle type information, and information on the driving position and vehicle speed at which the vertical acceleration and wheel speed fluctuations occur in the vehicle, the detected driving position and vehicle speed of the vehicle, as well as information on combinations of wheel speed fluctuations and vertical acceleration corresponding to the vehicle type of the vehicle, the system reads out. Based on the information on the combination of wheel speed fluctuations and vertical acceleration read from the database, and the calculated wheel speed fluctuations of the vehicle, the vertical acceleration occurring in the vehicle is estimated. A method for estimating vertical acceleration, characterized by the features described above.

2. Based on the information on the combination of wheel speed fluctuations and vertical acceleration read from the aforementioned database, the first vertical acceleration corresponding to the calculated wheel speed fluctuations of the vehicle is calculated. Based on the pre-set vehicle model of the vehicle and the calculated wheel speed fluctuations of the vehicle, a second vertical acceleration, which is an estimated value of the vertical acceleration occurring in the vehicle, is estimated. The ratio of the first vertical acceleration to the second vertical acceleration is calculated as a correction coefficient. By correcting the second vertical acceleration with the correction coefficient, the vertical acceleration generated in the vehicle is estimated. The method for estimating vertical acceleration according to feature 1.

3. Based on the information from the aforementioned database regarding multiple combinations of wheel speed fluctuations and vertical acceleration, an approximate function of vertical acceleration with respect to wheel speed fluctuations is estimated. Based on the aforementioned approximation function and the calculated wheel speed fluctuations of the vehicle, the vertical acceleration occurring in the vehicle is estimated. The method for estimating vertical acceleration according to feature 1.

4. The database stores information on combinations of vertical acceleration and wheel speed fluctuations occurring in each of multiple vehicles of the same type, each having multiple different vehicle characteristics, and associates this information with the same vehicle type information. Based on the information of multiple combinations of wheel speed fluctuations and vertical acceleration read from the database, and the information of combinations of vertical acceleration and wheel speed fluctuations that occurred for each of the multiple vehicles stored in association with the same vehicle type information, the approximate function is calculated. The method for estimating vertical acceleration according to feature 3.

5. A vehicle control method characterized by controlling the braking and driving force of the vehicle based on the vertical acceleration of the vehicle estimated by the vertical acceleration estimation method described in any one of claims 1 to 4.

6. A vehicle control method characterized by controlling the braking force of the vehicle based on the vertical acceleration of the vehicle estimated by the vertical acceleration estimation method described in any one of claims 1 to 4.

7. A positioning device that detects the vehicle's position, A sensor that detects the vehicle speed of the vehicle, A database that stores vehicle type information, information on combinations of vertical acceleration and wheel speed fluctuations occurring in a vehicle of the vehicle type information, and information on the driving position and vehicle speed at which the vertical acceleration and wheel speed fluctuations occur in the vehicle, in association with each other. At least one processor that performs the following: a process for calculating the wheel speed fluctuation of the vehicle; a process for reading information from the database regarding the combination of wheel speed fluctuation and vertical acceleration corresponding to the detected driving position and speed of the vehicle and the type of vehicle; and a process for estimating the vertical acceleration occurring in the vehicle based on the information regarding the combination of wheel speed fluctuation and vertical acceleration read from the database and the calculated wheel speed fluctuation of the vehicle. A vertical acceleration estimation system characterized by comprising the following features.

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