Vehicle control device and vehicle control method

Abstract

A vehicle control device according to the present invention includes a vertical motion control unit that can independently control braking / driving torques of at least front wheels and rear wheels of a vehicle and performs vibration suppression control for reducing vibration of the vehicle body by using a component of a reaction force of the braking / driving torques in the vehicle vertical direction. The vertical motion control unit estimates a reference posture of the vehicle based on vehicle control, and executes the vibration suppression control so as to obtain a posture close to the reference posture by referencing the difference between the reference posture and the actual posture of the vehicle.

Description

Vehicle control device, vehicle control method

[0001] The present invention relates to a vehicle control device and a vehicle control method.

[0002] Technologies have been developed to suppress vibrations associated with vehicle operation. Patent Document 1 discloses a vehicle vibration control device that controls the drive output of a vehicle to suppress pitch or bounce vibration of the vehicle, and includes a vibration control unit that controls the drive torque of the vehicle to suppress the amplitude of the pitch or bounce vibration based on the wheel torque acting on the wheel that occurs at the point where the vehicle's wheels contact the road surface, and a compensation component adjustment unit that reduces the amplitude of a compensation component that compensates for the wheel torque for suppressing the pitch or bounce vibration calculated by the vibration control unit as the magnitude of the steering angular velocity of the vehicle increases.

[0003] Japanese Patent Application Publication No. 2016-175604

[0004] The invention described in Patent Document 1 still has room for improvement in terms of improving the ride comfort of the vehicle.

[0005] A vehicle control device according to a first aspect of the present invention is a vehicle control device that can independently control the braking and driving torque of at least the front and rear wheels of a vehicle, and includes a vertical motion control unit that performs vibration damping control to reduce vehicle body vibration using the vertical component of the reaction force of the braking and driving torque, wherein the vertical motion control unit estimates a reference posture, which is the posture of the vehicle, based on vehicle control, and performs vibration damping control to approach the reference posture by referring to the difference between the reference posture and the actual posture, which is the posture of the vehicle. A vehicle control method according to a second aspect of the present invention is a vehicle control method performed by a vehicle control device, which is a computer mounted on a vehicle, wherein the vehicle can independently control the braking and driving torque of at least the front and rear wheels, and includes vibration damping processing to reduce vehicle body vibration using the vertical component of the reaction force of the braking and driving torque, wherein the vibration damping processing estimates a reference posture, which is the posture of the vehicle, based on vehicle control, and performs vibration damping control to approach the reference posture by referring to the difference between the reference posture and the actual posture, which is the posture of the vehicle.

[0006] According to the present invention, the ride comfort of a vehicle can be improved.

[0007] Schematic diagram of the vehicle control device Schematic diagram of the vehicle configuration Hardware configuration diagram of the vehicle control device Diagram explaining how the vehicle moves up and down due to vertical torque Diagram showing the vehicle's driving environment Diagram showing the vehicle's attitude during turning Diagram showing the time-series changes of roll angle and control torque Diagram of the configuration of a comparative example Diagram showing the time-series changes of vibration damping torque in the comparative example Diagram showing variations of the vertical movement control unit in the modified example Diagram of the vehicle configuration in the second embodiment Diagram showing attitude control in the second embodiment

[0008] —First Embodiment— The first embodiment of the vehicle control device will be described below with reference to Figures 1 to 9.

[0009] Figure 1 is a schematic diagram of the vehicle control device 2. The vehicle 1 comprises the vehicle control device 2, a detection device 4, and an I / O device 5. The detection device 4 is a general term for the sensors provided in the vehicle 1, and will be described in detail later. Each data obtained by the detection device 4 is transmitted to the I / O device 5. The I / O device 5 provides the data obtained from the detection device 4 to the vehicle control device 2. For example, the I / O device 5 performs AD conversion on the current and voltage output by the detection device 4 and transmits it to the vehicle control device 2. Also, for example, the I / O device 5 performs scaling processing on the digital signals output by the detection device 4 and transmits them to the vehicle control device 2.

[0010] The data input to the I / O device 5 includes accelerator pedal position, brake pedal force, steering wheel angle, output from multiple acceleration sensors, and motor-related data. Accelerator pedal position, brake pedal force, and steering wheel angle are the amounts of accelerator, brake, and steering wheel operation performed by the driver operating vehicle 1. As will be described later, vehicle 1 is equipped with multiple acceleration sensors, and the output of horizontal and vertical acceleration at various points on vehicle 1 is input to the I / O device 5. Vehicle 1 is equipped with multiple in-wheel motors, and data related to these in-wheel motors is also input to the I / O device 5.

[0011] The data output by the I / O device 5 to the vehicle control device 2 is classified into vehicle operation data 51, vertical vibration data 52, and other sensor data 53. Vehicle operation data 51 includes data on accelerator opening, brake pedal force, and steering wheel angle. Vertical vibration data 52 includes data on the vertical acceleration of the vehicle 1. Other sensor data 53 is the data obtained by subtracting the vehicle operation data 51 and vertical vibration data 52 from the data input to the I / O device 5. Other sensor data 53 includes data related to vehicle speed, the direction of travel of the vehicle 1, etc. Basic vehicle data 54 is static data that does not change regarding the vehicle 1, such as the weight, shape, and dimensions of the vehicle 1. Basic vehicle data 54 is pre-input into the I / O device 5. However, basic vehicle data 54 may also be pre-stored in the vehicle control device 2.

[0012] The vehicle control device 2 comprises a reference posture calculation unit 21, an actual posture calculation unit 22, a difference calculation unit 23, a distribution unit 24, a vertical movement control unit 25, an acceleration / deceleration torque determination unit 26, and a torque addition unit 27. The reference posture calculation unit 21 calculates a reference posture 211, which is the posture of the vehicle 1 based on vehicle control. The reference posture 211 includes roll, pitch, and heave. Vehicle operation data 51, vehicle basic data 54, and other sensor data 53 are input to the reference posture calculation unit 21. The reference posture calculation unit 21 assumes that there are no bumps on the road on which the vehicle 1 is traveling and calculates the posture of the vehicle 1 after the change if the vehicle 1 is successful, based on the vehicle operation data 51. For example, if the steering angle is not zero degrees, the roll angle of the vehicle 1 is calculated based on the speed of the vehicle 1, the center of gravity position of the vehicle 1, and the steering angle.

[0013] The actual posture calculation unit 22 calculates the actual posture 221, which is the current actual posture of the vehicle 1. The actual posture calculation unit 22 receives vehicle basic data 54 and other sensor data 53 as input. For example, if the vehicle 1 is equipped with a 3-axis gyro sensor, the output of that gyro sensor may be used as the actual posture 221. The difference calculation unit 23 calculates the posture difference 231, which is the difference between the reference posture 211 and the actual posture 221, and outputs it to the distribution unit 24. The distribution unit 24 outputs the posture difference 231 to the vertical movement control unit 25. Since there are four vertical movement control units 25, one for each of the in-wheel motors provided in the vehicle 1, there are four distribution outputs 241, which are the outputs of the distribution unit 24.

[0014] The vertical motion control unit 25 outputs a vibration damping torque 251 using the vertical vibration data 52 and the distribution output 241. Specifically, the vertical motion control unit 25 uses the sum of the value obtained by multiplying the distribution output 241 by a predetermined gain Gp and the value obtained by integrating the vertical vibration data 52 and multiplying it by a predetermined gain Gc as the vibration damping torque 251. However, the gains Gp and Gc differ for each motor, especially for the front and rear wheels. The relationship between the vibration damping torque 251 and the force acting on the vehicle 1 will be described later.

[0015] The acceleration / deceleration torque determination unit 26 outputs acceleration / deceleration torques 261 to operate each motor provided in the vehicle 1 based on the vehicle operation data 51. Four of these acceleration / deceleration torques 261 are calculated, corresponding to each of the in-wheel motors. The torque addition unit 27 calculates a torque command value 271 by adding the vibration damping torque 251 output by the vertical movement control unit 25 and the acceleration / deceleration torques 261 output by the acceleration / deceleration torque determination unit 26. The torque addition unit 27 outputs the calculated torque command value 271 to each of the in-wheel motors.

[0016] Figure 2 is a schematic diagram of vehicle 1. Vehicle 1 is a passenger car that travels on roads carrying occupants and has four wheels: the left front wheel 8FL, the right front wheel 8FR, the left rear wheel 8RL, and the right rear wheel 8RR. Hereafter, the left front wheel 8FL and the right front wheel 8FR will be collectively referred to as the front wheels 8F, and the left rear wheel 8RL and the right rear wheel 8RR will be collectively referred to as the rear wheels 8R. As mentioned above, vehicle 1 is equipped with a vehicle control device 2, a detection device 4, and an I / O device 5. However, the I / O device 5 is not shown in this figure.

[0017] Vehicle 1 is equipped with four acceleration sensors: a left front wheel acceleration sensor 3FL, a right front wheel acceleration sensor 3FR, a left rear wheel acceleration sensor 3RL, and a right rear wheel acceleration sensor 3RR. These acceleration sensors are installed near each wheel, preferably directly above each wheel. The outputs of these acceleration sensors are input to the vehicle control device 2 via a detection device 4 and an I / O device 5. Hereinafter, the left front wheel acceleration sensor 3FL and the right front wheel acceleration sensor 3FR will be collectively referred to as the "front acceleration sensors." The left rear wheel acceleration sensor 3RL and the right rear wheel acceleration sensor 3RR will be collectively referred to as the "rear acceleration sensors."

[0018] Vehicle 1 is equipped with independent actuators, such as in-wheel motors 7, that drive each wheel. The in-wheel motors 7 are a collective term for the left front motor 7FL, the right front motor 7FR, the left rear motor 7BL, and the right rear motor 7BR. The vehicle control device 2 outputs a left front wheel torque command TFL to the left front motor 7FL, a right front wheel torque command TFR to the right front motor 7FR, a left rear wheel torque command TRL to the left rear motor 7BL, and a right rear wheel torque command TRR to the right rear motor 7BR. The collective term for the left front wheel torque command TFL, the right front wheel torque command TFR, the left rear wheel torque command TRL, and the right rear wheel torque command TRR is the torque command value 271.

[0019] Figure 3 is a hardware configuration diagram of the vehicle control device 2. The vehicle control device 2 is a computer comprising a CPU 41 which is a central processing unit, a ROM 42 which is a read-only storage device, a RAM 43 which is a read-write storage device, an input / output device 44 which is a user interface, and a communication device 45. The CPU 41 performs the various calculations mentioned above by loading the program stored in the ROM 42 into the RAM 43 and executing it.

[0020] The vehicle control device 2 may be implemented using a rewritable logic circuit such as an FPGA (Field Programmable Gate Array) or an application-specific integrated circuit such as an ASIC (Application Specific Integrated Circuit) instead of the combination of CPU 41, ROM 42, and RAM 43. Alternatively, the vehicle control device 2 may be implemented using a different configuration, such as a combination of CPU 41, ROM 42, RAM 43 and FPGA, instead of the combination of CPU 41, ROM 42, and RAM 43.

[0021] The input / output device 44 is a user interface operated by the occupants of the vehicle 1, and for example, it accepts input of basic vehicle data 54. However, the input / output device 44 is not an essential component of the vehicle control device 2. The communication device 45 is a communication module that enables communication between the vehicle control device 2 and other components mounted on the vehicle 1, such as sensors. There may be a separate communication device 45 for each communication standard, or one communication device 45 may support multiple communication standards. The communication device 45 may include an AD / DA converter. Although Figure 3 shows the vehicle control device 2 as being composed of a single hardware device for convenience, the vehicle control device 2 may be composed of multiple hardware devices.

[0022] FIG. 4 is a diagram for explaining the mechanism by which the vehicle 1 moves up and down due to the vertical movement torque. However, the upper diagram of FIG. 4 shows the case where the in-wheel motor 7 is used as shown in FIG. 2, and the lower diagram of FIG. 4 shows the case where the number of power sources is less than that of the drive wheels and a drive shaft is used. When braking and driving forces are generated, due to the suspension geometry, forces for moving the vehicle 1 forward and backward and forces for moving the vehicle 1 up and down are generated from the reaction force. Although the structure of the suspension is complex, when the wheels move up and down, instantaneously, they move in an arc as if they are supported by a virtual arm from the instantaneous rotation center determined by the suspension geometry. Among these instantaneous rotation centers, the front of the vehicle 1 is called the front instantaneous rotation center CRF, and the rear of the vehicle 1 is called the rear instantaneous rotation center CRR. Among the aforementioned virtual arms, the arm connecting the front instantaneous rotation center CRF and the center of the front wheel 8F is called the front side view swing arm SF, and the arm connecting the rear instantaneous rotation center CRR and the center of the rear wheel 8R is called the rear side view swing arm SR.

[0023] Since the front side view swing arm SF and the rear side view swing arm SR are not horizontal, forces for lifting the vehicle 1 and forces for pushing down the vehicle 1 are generated by the reaction force of the braking and driving forces. Hereinafter, the vertically upward force acting on the front wheel 8F is called the front wheel jacking force F ＪＦ and the vertically upward force acting on the rear wheel 8R is called the rear wheel jacking force F ＪＲ . Note that when the front wheel jacking force F ＪＦ or the rear wheel jacking force F ＪＲ is negative, it represents a pushing-down force. The front wheel jacking force F ＪＦ and the rear wheel jacking force F ＪＲ can be expressed as follows using the front arm angle θ Ｆ and the rear arm angle θ Ｒ . Each of the front arm angle θ Ｆ and the rear arm angle θ Ｒ is the angle formed by the front side view swing arm SF and the rear side view swing arm SR with the horizontal direction. Note that in this specification, "x" in the mathematical formula represents a multiplication symbol.

[0024] F ＪＦ = FＦ x tan θ Ｆ ... (Equation 1) F ＪＲ = F Ｒ x tan θ Ｒ ... (Equation 2)

[0025] In Figure 4, braking force is generated on the front wheel 8F and driving force is generated on the rear wheel 8R. In this case, both the front wheel 8F and the rear wheel 8R generate a positive jacking force that lifts the vehicle 1. Here, if the magnitude of the braking force of the front wheel 8F and the magnitude of the driving force of the rear wheel 8R are equal, the vehicle motion does not change in the longitudinal direction, and only the upward movement of the vehicle 1 occurs. Using the above mechanism, the vehicle 1 is moved up and down by the torque of the wheels. In this embodiment, this torque is called the vertical torque.

[0026] An example of vibration damping will be explained with reference to Figures 5 to 7. Figure 5 shows the driving environment of vehicle 1, Figure 6 shows the attitude of vehicle 1 during a turn, and Figure 7 shows the time-series change of vibration damping torque. As shown in Figure 5, vehicle 1 is traveling in the area enclosed by the left outer line 20L and the right outer line 20R. The section from the curve start point 20S to the curve end point 20E in front of vehicle 1 is a curved section that turns to the left. As shown in the upper part of Figure 6, when vehicle 1 travels through the curved section, unless the vehicle speed is kept very slow, a change in the attitude of vehicle 1 due to planar motion occurs, for example, an inclination of angle φ. Angle φ is the angle with the vertical direction of the ground coordinate system, i.e., the direction of gravity.

[0027] When vehicle 1 is traveling on a curve, if there are irregularities on the road surface, roll vibration may occur in vehicle 1 as shown in the lower diagram of Figure 6. In this case, the center of vibration is not in the vertical direction but at the angle φ after the change in posture. In this embodiment, the reference posture calculation unit 21 calculates a posture tilted by angle φ as the reference posture 211, and calculates the difference between the reference posture 211 and the actual posture 221, Δφ, as the posture difference 231. The vertical motion control unit 25 then determines the vibration damping torque 251 so that this posture difference 231 becomes zero. If an attempt is made to make the tilt of the actual posture 221 zero without using the reference posture 211, the angle difference with respect to the vertical, Δφz, will be made zero, and sufficient effect cannot be obtained.

[0028] Figure 7 shows the time-series changes in roll angle and control torque. In both graphs, the horizontal axis is time, and the times in the two graphs are synchronized. However, in this figure, the vertical movement control unit 25 is disabled until time t1 in order to clearly show the effect of the vertical movement control unit 25. At time t0 on the far left of the figure, vehicle 1 has passed the curve start point 20S and has started turning. First, let's explain the time-series change in roll angle. As the turn begins, the roll angle increases and repeatedly increases and decreases in small increments due to unevenness in the road surface, etc. When the vertical movement control unit 25 is enabled at time t1, the average value of the roll angle over a short period of time remains approximately constant, but the small increases and decreases in the roll angle disappear, and the roll angle becomes stable.

[0029] Next, we will explain the time-series change of the vibration damping torque. From time t0 to time t1, the vertical movement control unit 25 is disabled, so the vibration damping torque remains zero until time t1. After time t1, the vibration damping torque increases and decreases in small increments to make Δφ zero. This increase and decrease ensures a stable roll angle after time t1.

[0030] (Comparative Example) A comparative example will be described with reference to Figures 8 and 9. Figure 8 is a configuration diagram of the comparative example and corresponds to Figure 1 in the first embodiment. The comparative example control device 2Z differs from the vehicle control device 2 in the embodiment in that it does not have a reference attitude calculation unit 21, an actual attitude calculation unit 22, and a difference calculation unit 23. The comparative example vertical motion control unit 25Z calculates a value v in the velocity domain by integrating the vertical vibration data 52. The comparative example control device 2Z then calculates a value x in the position domain obtained by further integrating this value v, and the sum of the value obtained by multiplying the value v by a predetermined gain Gc and the value obtained by multiplying the value x by a predetermined gain Gp is ​​taken as the vibration damping torque 251Z. The operation of the acceleration / deceleration torque determination unit 26 and the torque addition unit 27 is the same as in the embodiment.

[0031] Figure 9 shows the time-series change of vibration damping torque in the comparative example, and corresponds to Figure 7 in the first embodiment. That is, Figure 9 shows the time-series change of roll angle and control torque in the comparative example. However, in this figure as well, the comparative example's vertical movement control unit 25Z is disabled until time tz1. At time tz0, the leftmost point of the figure, vehicle 1 passes the curve start point 20S and begins turning. Since the comparative example's vertical movement control unit 25Z is disabled until time tz1, the behavior from time tz0 to time tz1 is the same as in Figure 7. From time tz1 onward, the comparative example's vertical movement control unit 25Z is operating. At time tz1, the comparative example's vertical movement control unit 25Z greatly increases the vibration damping torque so that the roll angle becomes zero. After that, the vibration damping torque maintains a large value in order to make the roll angle zero, and the value of the vibration damping torque increases or decreases due to vibrations centered on the vehicle angle φ. However, the roll angle does not stabilize and continues to fluctuate.

[0032] According to the first embodiment described above, the following effects can be obtained. (1) The vehicle control device 2 is equipped with a vertical motion control unit 25 that can independently control the braking and driving torque of at least the front and rear wheels of the vehicle 1 and performs vibration damping control to reduce the vibration of the vehicle body 1 using the vertical component of the reaction force of the braking and driving torque. The vertical motion control unit 25 estimates a reference posture 211, which is the posture of the vehicle 1 based on vehicle control, and performs vibration damping control by referring to the difference between the reference posture 211 and the actual posture 221, which is the actual posture of the vehicle, so that it approaches the reference posture 211, in other words, so that the posture difference 231 becomes zero.Therefore, the ride comfort can be improved by bringing the posture of the vehicle 1 closer to the reference posture 211 rather than tilting to zero.In the comparative example shown in Figure 9, an attempt is made to make the tilt of the posture zero, but when the center of vibration is not zero, it is not easy to maintain the posture and the contribution to improving the ride comfort is small.On the other hand, in this embodiment, as shown in Figures 6 and 7, the vertical motion control unit 25 approaches the reference posture 211, which is the center of vibration, so vibration can be effectively suppressed and the ride comfort of the vehicle 1 can be improved.

[0033] (2) The reference posture 211 is at least one of roll, pitch, and heave.

[0034] (Modification Example 1) FIG. 10 is a diagram showing variations of the vertical movement control unit 25. FIG. 10(a) shows the vertical movement control unit 25 in the first embodiment, and FIGS. 10(b) and 10(c) show the vertical movement control unit 25A and the vertical movement control unit 25B in this modification example. As shown in the first embodiment, the vertical movement control units 25 actually exist corresponding to the respective in-wheel motors 7. However, in this figure, only the vertical movement control unit 25 corresponding to one in-wheel motor 7 is shown for the convenience of drawing.

[0035] As shown in FIG. 10(a), in the above-described first embodiment, the value obtained by multiplying the posture difference 231, which is the difference between the reference posture 211 and the actual posture 221, by a predetermined gain Gp, and the value obtained by multiplying another gain Gc by the vertical vibration data 52, which is the vertical vibration of the vehicle 1 measured by the sensor, are added together to obtain the vibration damping torque 251. However, as shown in FIG. 10(b), instead of the vertical vibration data 52, the vibration damping torque 251 may be calculated using the value a in the acceleration region obtained by differentiating the posture difference 231 twice in the distribution unit 24B.

[0036] Further, as shown in FIG. 10(c), the values may be added together in each of the position region and the velocity region before multiplying by the respective gains while using the vertical vibration data 52. Specifically, first, the vertical vibration data 52 is integrated in the same manner as in the comparative example to calculate the value v in the velocity region, and the value x in the position region obtained by further integrating this value v is calculated. In addition, the distribution unit 24C not only outputs the posture difference 231 as it is but also outputs the value in the velocity region obtained by differentiating the posture difference 231 once. After adding together the two values in the position region calculated in this way, a predetermined gain Gp is multiplied. Also, after adding together the two values in the velocity region calculated, a predetermined gain Gc is multiplied. Finally, these are added together to calculate the vibration damping torque 251.

[0037] (Modification 2) In the first embodiment described above, the reference posture calculation unit 21 assumed that the road on which the vehicle 1 travels was flat. However, the reference posture calculation unit 21 may calculate the reference posture 211 by taking into account the slope of the road on which the vehicle 1 travels. The reference posture calculation unit 21 may use the output of a sensor mounted on the vehicle 1 that is capable of measuring the slope of the road. Alternatively, the reference posture calculation unit 21 may identify the slope of the road on which the vehicle 1 travels by combining a map database containing road slope data with its own position. This road slope includes not only the longitudinal slope in the direction of travel, such as uphill and downhill slopes, but also the transverse slope in the direction of crossing the road. The longitudinal slope affects the pitch angle, and the transverse slope affects the roll angle. For example, if the roll angle based on planar motion is 5 degrees and the transverse slope is 5 degrees, such as when driving on a curve, the roll angle in the reference posture 211 is calculated to be 10 degrees.

[0038] According to this modified example, in addition to the effects and advantages of the first embodiment, the following effects and advantages can be obtained: (3) The reference posture 211 includes the effect of the slope of the road surface on which the vehicle 1 travels. Therefore, the vehicle control device 2 can calculate the reference posture 211 that reflects the effects of the transverse slope and longitudinal slope, and suppress vibrations more accurately.

[0039] (Modification 3) In the first embodiment described above, the vehicle control device 2 was able to control all three: roll, pitch, and heave. However, the vehicle control device 2 only needs to be able to control at least one of the roll, pitch, and heave.

[0040] (Modification Example 4) In the above-described first embodiment, the reference attitude calculation unit 21 and the actual attitude calculation unit 22 are provided, and the difference between the reference attitude 211 and the actual attitude 221 output by both is calculated. However, the attitude difference 231 may be directly calculated without calculating the reference attitude 211 and the actual attitude 221. As shown in FIG. 6, since the tire is in direct contact with the road and is difficult to vibrate, the vehicle body connected via a damper (not shown) is likely to vibrate. Here, a sensor arranged on the tire side rather than the damper is called a "sprung mass sensor", and a sensor arranged on the vehicle body on the side opposite to the tire with respect to the damper is called a "sprung mass sensor". The attitude difference 231 can be directly calculated using the difference between the output of the sprung mass sensor and the output of the unsprung mass sensor. For example, when the sprung mass sensor and the unsprung mass sensor are triaxial gyros, the difference between the roll angle of the sprung mass gyro and the roll angle of the unsprung mass gyro can be used as the roll angle of the attitude difference 231.

[0041] (Modification Example 5) The reference attitude calculation unit 21 may simply calculate the reference attitude 211 and the actual attitude 221 as follows. The reference attitude calculation unit 21 may consider that the attitude near the tire of the vehicle 1 is the reference attitude 211, and simply calculate the reference attitude 211 using the output of a sensor mounted near the tire, that is, the "sprung mass sensor". In this case, the actual attitude calculation unit 22 can calculate the actual attitude 221 using the output of a sensor mounted on the vehicle body of the vehicle 1, that is, the "sprung mass sensor". Further, when the same type of sensors are mounted on the sprung mass and the unsprung mass, it is not necessary to calculate the reference attitude 211 and the actual attitude 221 separately. That is, in this case, the attitude difference 231 may be directly calculated using the difference between the outputs of the same type of sensors without calculating the reference attitude 211 and the actual attitude 221.

[0042] According to this modification example, in addition to the effects of the first embodiment, the following effects can be obtained. (4) The vehicle control device 2 calculates each of the reference attitude 211 and the actual attitude 221, or the attitude difference 231, using the output value of the sprung mass sensor of the vehicle 1 and the output value of the unsprung mass sensor of the vehicle 1. Therefore, the vertical movement control unit 25 can easily calculate the attitude difference 231.

[0043] (Modification 6) In the first embodiment described above, the output of a sensor mounted on the vehicle was used to calculate the actual posture 221. However, the actual posture 221 may be calculated using the output of a rotation speed sensor built into the in-wheel motor 7 without mounting a special sensor. In this case, the vertical movement of each tire can be calculated based on the change in rotation speed, and it can be used as a substitute for an acceleration sensor that measures the direction of gravity.

[0044] According to this modified version, in addition to the effects and advantages of the first embodiment, the following effects and advantages can be obtained. (5) The vehicle 1 is equipped with in-wheel motors 7, which are motors, on each wheel. The vertical movement control unit 25 uses the rotational speed data of the in-wheel motors 7 to calculate the actual posture 221. Therefore, the number of sensors mounted on the vehicle 1 can be reduced.

[0045] (Modification 7) In the first embodiment described above, the reference posture 211 was the posture of the vehicle body due to the planar motion of the vehicle 1. However, the effect of active control in the vehicle 1 may also be taken into account in the reference posture 211. For example, the vehicle control device 2 further includes an active control unit (not shown), which dynamically changes the characteristics of the active suspension connecting the tires and the vehicle body using known technology. The reference posture calculation unit 21 calculates the reference posture 211 using the characteristics of the active suspension changed by the active control unit.

[0046] According to this modified example, in addition to the effects and advantages of the first embodiment, the following effects and advantages can be obtained. (6) The reference posture 211 is the posture of the vehicle body obtained by adding the effect of active control to the posture of the vehicle body due to the planar motion of the vehicle 1.

[0047] (Modification 8) In the first embodiment described above, the reference attitude 211 was roll, pitch, and heave. However, the reference attitude 211 may also be the time variation of roll, pitch, and heave, i.e., the first derivative in the velocity domain, or the second derivative in the acceleration domain obtained by further differentiation. In this case, however, the actual attitude 221 and attitude difference 231 shall also have the same dimensions as the reference attitude 211. Furthermore, the distribution unit 24 shall differentiate or integrate the attitude difference 231 as needed and output it to the vertical movement control unit 25.

[0048] —Second Embodiment— A second embodiment of the vehicle control device will be described with reference to Figures 11 to 12. In the following description, the same reference numerals are used for components that are the same as in the first embodiment, and the differences will be mainly explained. Points that are not specifically explained are the same as in the first embodiment. This embodiment differs from the first embodiment mainly in that it focuses only on pitch control.

[0049] Figure 11 is a diagram showing the configuration of vehicle 1A in the second embodiment. In this embodiment, the left front wheel 8FL and the right front wheel 8FR are collectively referred to as the front wheel 8F, and the left rear wheel 8RL and the right rear wheel 8RR are collectively referred to as the rear wheel 8R. Vehicle 1A is equipped with a front wheel acceleration sensor 3F and a rear wheel acceleration sensor 3R for detecting the vertical acceleration of vehicle 1A. The front wheel acceleration sensor 3F is installed near the axle of the front wheel 8F, and the rear wheel acceleration sensor 3R is installed near the axle of the rear wheel 8R. Vehicle 1A is equipped with a front motor 7F for driving the front wheel 8F and a rear motor 7R for driving the rear wheel 8R.

[0050] The vehicle control device 2A calculates a front wheel torque command TF for driving the front wheels 8F and a rear wheel torque command TR for driving the rear wheels 8R. The front motor 7F outputs torque according to the front wheel torque command TF output by the vehicle control device 2A. The rear motor 7R outputs torque according to the rear wheel torque command TR output by the vehicle control device 2A. In this embodiment, the vehicle control device 2A includes vertical movement control units 25 corresponding to the front motor 7F and the rear motor 7R, respectively. In this embodiment, the reference attitude calculation unit 21 and the actual attitude calculation unit 22 focus only on pitch.

[0051] Figure 12 shows the attitude control in the second embodiment. When the vehicle 1 accelerates or decelerates, a change in pitch occurs, causing the vehicle 1 to tilt in the longitudinal direction. The upper part of Figure 12 shows, for example, a state in which the front of the vehicle 1 sinks due to acceleration while moving forward, resulting in a change in pitch angle θ. If there are irregularities on the road surface at this time, the angle θ is not a constant value, and vibrations with an amplitude Δθ centered on θ occur. In this embodiment, the number of actuators is smaller than in the first embodiment, so it is limited to pitch, but the deviation of the pitch from the reference attitude 211 is calculated as the attitude difference 231, and control is made to make the attitude difference 231 zero.

[0052] In the embodiments and modifications described above, the configuration of the functional blocks is merely an example. Several functional configurations shown as separate functional blocks may be integrated, or a configuration represented in one functional block diagram may be divided into two or more functions. Furthermore, some of the functions of each functional block may be provided by other functional blocks. In particular, the reference posture calculation unit 21, the actual posture calculation unit 22, and the difference calculation unit 23 may be integrated, or the reference posture calculation unit 21 and the actual posture calculation unit 22 may be omitted, and the difference calculation unit 23 may directly calculate the posture difference 231 using the output of a sensor or the like. Moreover, the functions of the reference posture calculation unit 21, the actual posture calculation unit 22, the difference calculation unit 23, and the distribution unit 24 may be included in the vertical movement control unit 25.

[0053] In the embodiments and modifications described above, the program is stored in ROM 42, but the program may also be stored in a non-volatile storage device (not shown). Furthermore, the vehicle control device 2 may have an input / output interface (not shown), and the program may be read from another device via a medium usable by the input / output interface and the vehicle control device 2 when necessary. Here, "medium" refers to, for example, a storage medium detachable from the input / output interface, or a communication medium, i.e., a wired, wireless, or optical network, or a carrier wave or digital signal propagating through such a network. Also, some or all of the functions realized by the program may be realized by hardware circuits or FPGAs.

[0054] The embodiments and modifications described above may be combined in any way. Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that can be conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0055] 1: Vehicle 2: Vehicle control device 7: In-wheel motor 21: Reference posture calculation unit 22: Actual posture calculation unit 23: Difference calculation unit 24: Distribution unit 24B: Distribution unit 24C: Distribution unit 25: Vertical movement control unit 51: Vehicle operation data 52: Vertical vibration data 53: Other sensor data 54: Vehicle basic data 211: Reference posture 221: Actual posture 231: Posture difference 241: Distribution output 251: Vibration damping torque 261: Acceleration / deceleration torque 271: Torque command value

Claims

1. A vehicle control device comprising a vertical motion control unit capable of independently controlling the braking and driving torque of at least the front and rear wheels of a vehicle, and performing vibration damping control to reduce vehicle body vibration using the vertical component of the reaction force of the braking and driving torque, wherein the vertical motion control unit estimates a reference posture, which is the posture of the vehicle, based on vehicle control, and performs vibration damping control to approach the reference posture by referring to the difference between the reference posture and the actual posture, which is the actual posture of the vehicle.

2. A vehicle control device according to claim 1, wherein the reference posture is at least one of roll, pitch, and heave.

3. A vehicle control device according to claim 1, wherein the reference posture includes the influence of the inclination of the road surface on which the vehicle travels.

4. A vehicle control device according to claim 1, wherein the reference posture is the posture of the vehicle body obtained by adding the effect of active control to the posture of the vehicle body due to the planar motion of the vehicle.

5. A vehicle control device according to any one of claims 1 to 4, wherein the vertical movement control unit calculates the reference posture and the actual posture, or the difference between the reference posture and the actual posture, using the output values ​​of the sprung mass sensor and the unsprung mass sensor of the vehicle.

6. A vehicle control device according to any one of claims 1 to 4, wherein the vehicle is equipped with a motor for each wheel, and the vertical movement control unit calculates the actual posture using data on the rotation speed of the motors.

7. A vehicle control method executed by a vehicle control device, which is a computer mounted on a vehicle, wherein the vehicle is capable of independently controlling the braking and driving torques of at least the front wheels and the rear wheels, and includes a vibration damping process that reduces the vibration of the vehicle body using the vertical component of the reaction force of the braking and driving torques, wherein the vibration damping process estimates a reference posture, which is the posture of the vehicle based on vehicle control, and performs vibration damping control to approach the reference posture by referring to the difference between the reference posture and the actual posture, which is the actual posture of the vehicle.

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