Vehicle motion control device and vehicle motion control method

Abstract

This vehicle motion control device for controlling a vehicle comprises: front wheels and rear wheels for which braking / driving force can be independently controlled; and a vertical motion control unit which includes a front wheel acceleration sensor for measuring the vertical acceleration of the vehicle at the position of the front wheels as front part vertical acceleration, and a rear wheel acceleration sensor for measuring the vertical acceleration of the vehicle at the position of the rear wheels as rear part vertical acceleration, and which controls vehicle motion in the vertical direction generated in the vehicle by the reaction force to the braking / driving force. The vertical motion control unit calculates a control target position acceleration which is the vertical acceleration at a control target position by using the front part vertical acceleration, the rear part vertical acceleration, and the position, in the vehicle front-rear direction, of the control target position in the vehicle, and determines the braking / driving force by using the control target position acceleration.

Description

Vehicle motion control device, vehicle motion control method

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

[0002] Techniques for controlling the vibration of a vehicle have been widely studied. In Patent Document 1, there is disclosed a vehicle drive force control device including: a wheel suspended on a vehicle body via a suspension; vehicle body vertical vibration detection means for detecting the vertical vibration of the vehicle body; and drive force control means for creating a difference in the drive forces of the front and rear wheels in accordance with the detected vertical vibration of the vehicle body to suppress the vertical vibration of the vehicle body.

[0003] Japanese Patent Application Laid-Open No. 2006-109642

[0004] In the invention described in Patent Document 1, there is room for improvement in the control method.

[0005] The vehicle motion control device according to the first aspect of the present invention is a vehicle motion control device that controls a vehicle. The vehicle includes front wheels and rear wheels capable of independently controlling driving forces, a front wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the front wheels as the front vertical acceleration, and a rear wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the rear wheels as the rear vertical acceleration. The vehicle further includes a vertical motion control unit that controls the vertical vehicle motion generated in the vehicle by the reaction force of the driving force. The vertical motion control unit calculates a control target position acceleration, which is the vertical acceleration at the control target position, using the front vertical acceleration, the rear vertical acceleration, and the longitudinal position of the vehicle at the control target position in the vehicle, and determines the driving force using the control target position acceleration. The vehicle motion control method according to the second aspect of the present invention is a vehicle motion control method executed by a computer for a vehicle. The vehicle includes front wheels and rear wheels capable of independently controlling driving forces, a front wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the front wheels as the front vertical acceleration, and a rear wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the rear wheels as the rear vertical acceleration. The vehicle motion control method includes a vertical motion control step of controlling the vertical vehicle motion generated in the vehicle by the reaction force of the driving force. In the vertical motion control step, a control target position acceleration, which is the acceleration at the control target position, is calculated using the front vertical acceleration, the rear vertical acceleration, and the longitudinal position of the vehicle at the control target position in the vehicle, and the driving force is determined using the control target position acceleration.

[0006] According to the present invention, the effect of control at the control target position can be improved.

[0007] A plan view showing the configuration of the vehicle in the first embodiment. A functional block diagram of the vehicle motion control device in the first embodiment. A hardware configuration diagram of the vehicle motion control device. A diagram explaining the mechanism by which the vehicle moves up and down due to vertical torque. A diagram showing the vibration of the vehicle when the vertical movement control unit is not operating. A diagram showing the vibration when the prior art is applied. A diagram showing the vibration of the vehicle when the vertical movement control unit is operating. A plan view showing the configuration of the vehicle in the second embodiment. A functional block diagram of the vehicle motion control device in the second embodiment. A diagram showing the position of the occupant. A diagram showing the vibration of the vehicle in a forward view.

[0008] —First Embodiment— The first embodiment of the vehicle motion control device will be described below with reference to Figures 1 to 7.

[0009] Figure 1 is a plan view showing the configuration of a vehicle 1 equipped with a vehicle motion control device 2. Vehicle 1 is a passenger car that travels on roads with occupants on board, and has four wheels: a left front wheel 8FL, a right front wheel 8FR, a left rear wheel 8RL, and a right rear wheel 8RR. Hereinafter, 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. Vehicle 1 is equipped with a front wheel acceleration sensor 3F and a rear wheel acceleration sensor 3R that detect the vertical acceleration of the vehicle 1.

[0010] The front wheel acceleration sensor 3F is installed near the axle of the front wheel of the vehicle, and the rear wheel acceleration sensor 3R is installed near the axle of the rear wheel of the vehicle. The vehicle 1 is equipped with a front motor 7F that drives the front wheel 8F and a rear motor 7R that drives the rear wheel 8R. The vehicle motion control device 2, shown approximately in the center of the vehicle 1, calculates a front wheel torque command TF that drives the front wheel 8F and a rear wheel torque command TR that drives the rear wheel 8R. However, the position of the vehicle motion control device 2 in Figure 1 is illustrative and may be located elsewhere in the vehicle 1. The vehicle motion control device 2 outputs the front wheel torque command TF to the front motor 7F and the rear wheel torque command TR to the rear motor 7R.

[0011] The front motor 7F outputs torque according to the front wheel torque command TF output by the vehicle motion control device 2. The rear motor 7R outputs torque according to the rear wheel torque command TR output by the vehicle motion control device 2. The vehicle 1 is equipped with reduction gears and shafts that transmit power, suspension that supports the tires, and inverters and batteries that control each motor, but their descriptions and explanations are omitted.

[0012] Figure 2 is a functional block diagram of the vehicle motion control device 2. The vehicle motion control device 2 comprises an operation information input unit 21, a vertical motion control unit 22, and an acceleration / deceleration torque determination unit 23. The operation information input unit 21 receives, for example, operation data of the accelerator pedal, brake pedal, and steering wheel operated by the driver (not shown). For example, the accelerator pedal and brake pedal are equipped with sensors that detect the amount the driver depresses each pedal, and the output of these sensors is input to the operation information input unit 21. The vertical motion control unit 22 receives the outputs of the front wheel acceleration sensor 3F and the rear wheel acceleration sensor 3R.

[0013] Furthermore, the vertical motion control unit 22 receives a pre-set vibration damping target position 800. The vibration damping target position 800 is data indicating the position in the vehicle 1 where vertical motion should be reduced the most, for example, data indicating the position of an occupant. Hereinafter, the position where vertical motion should be reduced the most will also be called the "control target position". This occupant may be the driver or someone sitting in the rear seat. The vehicle motion control device 2 uses this data to calculate the front wheel torque command TF and the rear wheel torque command TR. The vibration damping target position 800 may be stored in a non-volatile memory device provided by the vehicle motion control device 2, or it may be input from outside the vehicle motion control device 2.

[0014] The operation information input unit 21 outputs the input operation data of the accelerator pedal, brake pedal, and steering wheel to the acceleration / deceleration torque determination unit 23. The acceleration / deceleration torque determination unit 23 uses the data output by the operation information input unit 21 to determine the acceleration / deceleration torque of the front wheels 8F and rear wheels 8R. The vertical movement control unit 22 determines the vertical movement torque Tud from the outputs of the front wheel acceleration sensor 3F and rear wheel acceleration sensor 3R and the position information in the plane direction of the controlled object. The vertical movement torque Tud is added directly to the torque of the rear wheels 8R, and added to the front wheels 8F with the sign reversed to calculate the front wheel torque command TF that drives the front wheels 8F and the rear wheel torque command TR that drives the rear wheels 8R. The acceleration / deceleration torque determination unit 23 is essential for the vehicle 1 to function as a moving object, and the vehicle 1 cannot move if the operation information input unit 21 is not operating. Although the vertical movement control unit 22 is an essential component in this embodiment, the vehicle 1 can move even if the vertical movement control unit 22 is not operating.

[0015] Figure 3 is a hardware configuration diagram of the vehicle motion control device 2. The vehicle motion control device 2 includes 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.

[0016] The vehicle motion 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 motion control device 2 may be implemented using a different configuration instead of the combination of CPU 41, ROM 42, and RAM 43, for example, a combination of CPU 41, ROM 42, RAM 43 and FPGA.

[0017] The input / output device 44 is a user interface operated by the occupants of the vehicle 1, and for example, it receives input of vibration damping target position 800 from the occupants. However, the input / output device 44 is not an essential component of the vehicle motion control device 2. The communication device 45 is a communication module that enables communication between the vehicle motion control device 2 and other components mounted on the vehicle 1, such as sensors. There may be separate communication devices 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 motion control device 2 as being composed of a single hardware device for convenience, the vehicle motion control device 2 may be composed of multiple hardware devices.

[0018] Figure 4 illustrates the mechanism by which vehicle 1 moves up and down due to vertical torque. When a braking force is generated, the suspension geometry generates a reaction force that moves vehicle 1 forward and backward, and a force that moves vehicle 1 up and down. Although the structure of the suspension is complex, when the wheels move up and down, they move in an arc as if they were momentarily supported by a virtual arm from an instantaneous center of rotation determined by the suspension geometry. Of these instantaneous centers of rotation, the one in front of vehicle 1 is called the front instantaneous center of rotation CRF, and the one behind vehicle 1 is called the rear instantaneous center of rotation CRR. Of the aforementioned virtual arms, the arm connecting the front instantaneous center of rotation 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 center of rotation CRR and the center of the rear wheel 8R is called the rear side view swing arm SR.

[0019] Because the front side view swingarm SF and the rear side view swingarm SR are not horizontal, the reaction force of the braking and driving forces generates a force that lifts the vehicle 1 or a force that pushes the vehicle 1 down. Below, the vertical upward force acting on the front wheel 8F is the front wheel jacking force F. ＪＦ This refers to the vertical upward force acting on the rear wheel 8R, which is called the rear wheel jacking force F. ＪＲ It is called F. ＪＦ Rear wheel jacking force F ＪＲ A negative value indicates a downward force. Front wheel jacking force F ＪＦand the rear wheel jacking force F ＪＲ is expressed as follows using the front arm angle θ Ｆ and the rear arm angle θ Ｒ The front arm angle θ Ｆ and the rear arm angle θ Ｒ are respectively the angles formed by the front side view swing arm SF and the rear side view swing arm SR with the horizontal direction. In the present specification, "x" in the mathematical formula represents a multiplication symbol.

[0020] F ＪＦ = F Ｆ x tan θ Ｆ ... (Equation 1) F ＪＲ = F Ｒ x tan θ Ｒ ... (Equation 2)

[0021] In FIG. 4, a braking force is generated on the front wheel 8F and a driving force is generated on the rear wheel 8R. In this case, a positive jacking force that lifts the vehicle 1 is generated on both the front wheel 8F and the rear wheel 8R. Here, when the magnitude of the braking force of the front wheel 8F is equal to the magnitude of the driving force of the rear wheel 8R, the vehicle motion does not change in the front-rear direction, and only a motion in which the vehicle 1 moves upward occurs. Using the above mechanism, the vehicle 1 is moved up and down by the torque of the wheels. In the present embodiment, this torque is called the vertical movement torque.

[0022] Next, the operation of the vehicle motion control device 2 for suppressing the deterioration of the riding comfort of the vehicle 1 having the configuration described above will be described. In the present embodiment, the purpose of the vehicle motion control device 2 is vibration damping to reduce the vibration of the vehicle 1, and the position in the plane direction targeted for vibration damping is the passenger position where the passenger rides on the vehicle 1. However, the vehicle motion control device 2 may control for the purpose of vibration excitation that vibrates the vehicle 1, and the position in the plane direction targeted for control of the vertical vehicle motion may be any other arbitrary place such as the location of the cargo.

[0023] Figure 5 is a side view of vehicle 1, illustrating the vibration of vehicle 1 when the vertical motion control unit 22 is not operating. Figure 5 can also be said to show the vibration of a vehicle without the vertical motion control unit 22. Vehicle 1 vibrates back and forth between its position and the position 1v1 of the vehicle when it is not controlled. In this figure, the amplitude of the vibration of vehicle 1 is enlarged for ease of understanding. The amplitude of vibration is small at the front of vehicle 1 and large at the rear of vehicle 1, but this is also to make the operation of the embodiment easier to understand. In reality, there are various forms, such as the amplitude of vibration being roughly equal at the front and rear of the vehicle, or conversely, the amplitude of vibration being larger at the front. In addition, input from road surface irregularities is necessary for vibration to occur in the vehicle, but this is omitted from the illustration. Figure 5 shows an occupant P riding in the vehicle. Along with the vibration of vehicle 1, occupant P also vibrates back and forth between occupant P's position and the position 9v1 of the occupant's vibration when it is not controlled.

[0024] Figure 6 shows the vibration of a vehicle when conventional control technology is applied to the vehicle vibration shown in Figure 5. In other words, it is an example that shows a case in which a mechanism to reduce vibration is provided, but is not sufficient, unlike in Figure 5. In conventional control technology, the acceleration CGA at the vehicle's center of gravity is calculated using Gf, which is the output of the front wheel acceleration sensor 3F, and Gr, which is the output of the rear wheel acceleration sensor 3R, and the vertical torque is calculated from the vibration at the vehicle's center of gravity. Since the vehicle's center of gravity is approximately at the center of the vehicle, the acceleration detected by the front wheel acceleration sensor 3F is A ３Ｆ The acceleration detected by the rear wheel acceleration sensor 3R is A ３Ｒ Therefore, the acceleration CGA at the vehicle's center of gravity can be calculated using equation 3.

[0025] CGA = (A ３Ｆ +A ３Ｒ ) / 2 ... (Equation 3)

[0026] Here, as shown in Figure 6, if the vibration amplitude of the vehicle is small at the front of the vehicle 1 and large at the rear of the vehicle 1, the following problem arises. That is, if the vertical torque is calculated using the acceleration CGA of the vehicle's center of gravity calculated using Equation 3 and applied similarly to the front wheels 8F and rear wheels 8R, the jacking force is excessive for the vibration at the front wheels 8F and insufficient for the vibration at the rear wheels 8R. As a result, the vibration of the vehicle 1 becomes as shown in Figure 6, and the vibration of the occupant P becomes the position 9v2 of the occupant's vibration under conventional control, which is smaller than when there is no control, but vibration still remains.

[0027] Figure 7 shows the vibration of vehicle 1 when the vertical motion control unit 22 is operating. In this figure, the occupant position is the control target position. The difference from Figure 5 is that the vertical motion control unit 22 is operating, and the difference from Figure 6 is the control method. In the control in this embodiment, the vibration at the occupant position in the vehicle is calculated from the information of the front wheel acceleration sensor 3F and the rear wheel acceleration sensor 3R as the position in the plane that is the target of controlling the vertical motion of the vehicle, and the vertical motion torque Tud is calculated from the vibration at the occupant position. The wheelbase of vehicle 1 is L, and the occupant position is at the LPF distance from the front axle and at the LPR distance from the rear axle. These distances LPF and LPR are the vibration-damping target position 800 mentioned above. Here, if we represent the vertical force as Fud and the acceleration as AC, the following equation holds.

[0028] AC = (LPR x A) ３Ｆ + LPF x A ３Ｒ ) / L...(Formula 4) Fud = -Gain x ∫ AC dt...(Formula 5) Tud = r x Fud / tan θt...(Formula 6) θt=(θ Ｆ + θ Ｒ ) / 2 ... (Equation 7)

[0029] Equation 5 shows that the vertical force is obtained by multiplying the time integral of acceleration by a predetermined gain. Equation 6 shows that the product of the wheel radius r and the vertical force Fud is given by the front arm angle θ. Ｆ and rear arm angle θＲ This shows that the vertical torque Tud can be obtained by dividing by the tangent using the average of the two values. When the vertical torque Tud calculated using equations 4 to 7 is applied to the front wheel 8F and rear wheel 8R, the jacking force of the front wheel 8F becomes larger than that of the conventional technology, and the jacking force of the rear wheel 8R becomes smaller than that of the conventional technology. As a result, the vibration of the vehicle 1 becomes as shown in Figure 7, and the position of occupant P becomes a node of vibration, making it possible to suppress vibration at the position of occupant P.

[0030] According to the first embodiment described above, the following effects can be obtained. (1) The vehicle motion control device 2 controls a vehicle 1. The vehicle 1 includes front wheels 8F and rear wheels 8R whose braking and driving forces can be controlled independently, a front wheel acceleration sensor 3F that measures the vertical acceleration of the front wheel 8F as the front vertical acceleration, and a rear wheel acceleration sensor 3R that measures the vertical acceleration of the rear wheels as the rear vertical acceleration. The vehicle motion control device 2 includes a vertical motion control unit 22 that controls the vertical vehicle motion generated in the vehicle 1 by the reaction force of the braking and driving force. The vertical motion control unit 22 calculates the controlled target position acceleration, which is the acceleration at the controlled target position, using the front vertical acceleration, the rear vertical acceleration, and the longitudinal position of the controlled target position in the vehicle 1, and determines the braking and driving force using the controlled target position acceleration. As a result, the effect of control at the controlled target position, specifically the effect of vibration damping, can be improved. Specifically, the acceleration at the occupant position, which is the position where the control effect is to be maximized in the longitudinal direction of vehicle 1, was calculated as shown in Equation 4, and the vertical torque Tud was calculated using Equations 5 to 7 based on this acceleration.

[0031] Furthermore, even in the conventional control technology shown in Figure 6, it may be possible to suppress vibrations at the position of occupant P by significantly increasing the control gain and thus the vertical torque. However, the following two problems can be considered. Firstly, it is inefficient because a huge torque is required. Secondly, each motor has an upper limit on torque, so control becomes impossible when torque exceeding this upper limit is required. On the other hand, when using the method in this embodiment, vibrations at the position of occupant P can be effectively suppressed without using excessive torque.

[0032] (2) The controlled position is the position of the occupants in vehicle 1. Therefore, the vertical vibrations experienced by the occupants of vehicle 1 can be reduced.

[0033] (3) The vertical movement control unit 22 controls the vertical acceleration at the controlled position to be reduced.

[0034] (Modification 1) In the first embodiment described above, the "control target position," which is the position where the vehicle motion control device 2 wants to minimize vertical movement, was the position of the occupants. However, the control target position is not limited to the position of the occupants. For example, the control target position may be the mounting location of precision equipment or other devices that are adversely affected by vibration.

[0035] (Modification 2) In the first embodiment described above, the controlled position was set in advance in the vehicle motion control device 2. However, it may be set by the occupants of the vehicle 1 using the input / output device 44, or it may be set automatically. Alternatively, for example, it may be set by the occupants using a smartphone application, or it may be set automatically using the output of sensors installed in the vehicle, such as pressure sensors built into each seat or the output of a camera that photographs the interior of the vehicle 1. Alternatively, the location of an item owned by the occupants, such as a smartphone, may be identified and that location may be set as the controlled position. The location of the smartphone can be calculated, for example, by calculating the distance between the smartphone and a plurality of radio wave sources pre-installed in the vehicle 1.

[0036] This modified version provides the following effects in addition to those of the first embodiment: (4) The vertical motion control unit 22 identifies the control target position using the output of a sensor mounted on the vehicle 1 or the position information of a device held by the occupant. Therefore, the position of the occupant in the vehicle 1 can be identified without prior setting, and the vertical vibrations felt by that occupant can be efficiently reduced.

[0037] (Modification 3) In the first embodiment described above, the vehicle motion control device 2 controlled the torque command to reduce vibration at the controlled position. However, the vehicle motion control device 2 may also control the torque command to amplify vibration. In this case, the sign of the torque output by the vertical motion control unit 22 is reversed and added to the front wheel torque command TF and the rear wheel torque command TR. For example, the vertical motion torque Tud is calculated in the same manner as in the first embodiment, the vertical motion torque Tud is added directly to the front wheel torque command TF, and the sign of the vertical motion torque Tud is reversed before being added to the rear wheel torque command TR.

[0038] —Second Embodiment— A second embodiment of the vehicle motion control device will be described with reference to Figures 8 to 11. 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 utilizes the reaction force of the braking and driving force not only in the longitudinal direction but also in the lateral direction.

[0039] Figure 8 is a plan view showing the configuration of a vehicle 1A equipped with a vehicle motion control device 2A in the second embodiment. The vehicle 1A 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 motion control device 2A. 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 sensor." The left rear wheel acceleration sensor 3RL and the right rear wheel acceleration sensor 3RR will be collectively referred to as the "rear acceleration sensor."

[0040] Vehicle 1A 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 motion 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.

[0041] Figure 9 is a functional block diagram of the vehicle motion control device 2A. The vehicle motion control device 2A comprises an operation information input unit 21, a vertical motion control unit 22A, and an acceleration / deceleration torque determination unit 23A. The operation of the operation information input unit 21 is the same as in the first embodiment. The acceleration / deceleration torque determination unit 23A calculates the acceleration / deceleration torque of each motor using the data output by the operation information input unit 21. The vertical motion control unit 22A receives the outputs of the four acceleration sensors mentioned above and the vibration damping target position 800A as input. In the first embodiment, the vibration damping target position 800 indicated the longitudinal position of the vibration damping target on the vehicle 1. In this embodiment, the vibration damping target position 800A indicates the longitudinal and lateral positions of the vibration damping target on the vehicle 1. The lateral direction can also be called the width direction of the vehicle 1.

[0042] The vertical movement control unit 22A controls the left vertical movement torque Tud, which is the vertical movement torque on the left side of the vehicle 1. Ｌ And the vertical torque on the right side of vehicle 1 is the vertical torque Tud Ｒ And, calculate the left vertical movement torque Tud. Ｌ This value is reversed in sign and added to the left front wheel torque command TFL calculated by the acceleration / deceleration torque determination unit 23A, and this same value is added to the left rear wheel torque command TRL calculated by the acceleration / deceleration torque determination unit 23A. Right-right downward moving torque Tud Ｒ This value is reversed in sign and added to the right front wheel torque command TFR calculated by the acceleration / deceleration torque determination unit 23A, and this same value is added to the right rear wheel torque command TRR calculated by the acceleration / deceleration torque determination unit 23A.

[0043] Figure 10 shows the position of the occupant, which is the target of vibration damping, in a plan view. The wheelbase of vehicle 1 in the longitudinal direction is L, and the occupant's position is at LPF, which is the distance from the front axle, and LPR, which is the distance from the rear axle. In the lateral direction of vehicle 1, the tread is d, and the occupant's position is at dL, which is the distance from the center of the left wheel, and dR, which is the distance from the center of the right wheel.

[0044] Figure 11 shows the vibration of vehicle 1A in a forward view. The suppression of vibration of vehicle 1A as seen from the side is the same as in the first embodiment, so the explanation is omitted. The method for suppressing vibration of vehicle 1A as seen from the front is the same as the method for suppressing vibration as seen from the side. That is, the left vertical movement torque Tud Ｌ and upward and downward moving torque Tud Ｒ By adjusting the size of the element, vibrations at the position of occupant P can be suppressed by acting as a node of vibration at occupant P's position.

[0045] Left vertical movement torque Tud by vertical movement control unit 22A Ｌ and upward and downward moving torque Tud Ｒ The calculation is as follows: First, the vertical motion control unit 22A calculates the vertical acceleration at the occupant's position. However, this acceleration is the longitudinal-induced vertical acceleration AC, which is the acceleration caused by the longitudinal vibration of the vehicle 1A. ＦＲ AC is the lateral-induced vertical acceleration, which is the acceleration caused by the lateral vibration of vehicle 1A. ＬＲ and are calculated separately. Formulas 8 and 9 are used for this calculation. The LR and other terms described in formulas 8 and 9 are as explained with reference to Figure 10.

[0046] AC ＦＲ = (LR x (A ３ＦＬ +A ３ＦＲ ) + LPF x (A ３ＢＬ +A ３ＢＲ )) / L ... (Equation 8) AC ＬＲ = (dR x (A ３ＦＬ +A ３ＢＬ ) + dL x (A ３ＦＲ +A ３ＢＲ )) / d ... (Equation 9)

[0047] Next, the vertical movement control unit 22A controls the vertical acceleration AC caused by the front-to-back movement. ＦＲ The forward and backward-initiated vertical force Fud is calculated from the velocity obtained by integrating over time. ＦＲ , and left-right originating vertical acceleration AC ＬＲ The left-right initiated up-down force Fud is calculated from the velocity obtained by integrating over time. ＬＲ The values ​​are calculated using equations 10 and 11. The vertical movement control unit 22A also calculates the corresponding torques, which are the forward and backward-initiated vertical movement torques Tud ＦＲ , and left-right originating vertical torque Tud ＬＲ This is calculated using equations 12 and 13.

[0048] Fud ＦＲ = -Gain ＦＲ x ∫ AC ＦＲ dt ... (Equation 10) Fud ＬＲ = -Gain ＬＲ x ∫ AC ＬＲ dt ... (Equation 11) Tud ＦＲ = r x Fud ＦＲ / tan θt ... (Formula 12) Tud ＬＲ = r x Fud ＬＲ / tan θt ... (Equation 13)

[0049] Note that θt in equations 12 and 13 is calculated using equation 7, but in this embodiment, an in-wheel motor is used, so the front arm angle θ Ｆ and rear arm angle θ Ｒ The following changes: That is, the front side view swingarm SF connects the front instantaneous rotation center CRF and the ground contact position of the front wheel 8F, so the front arm angle θ is the angle between the front side view swingarm SF and the horizontal direction. Ｆ This value is larger than that of the first embodiment. The rear side view swing arm SR connects the rear instantaneous rotation center CRR and the ground contact position of the rear wheel 8R, so the rear arm angle θ is the angle between the rear side view swing arm SR and the horizontal direction. ＲThis value is larger than that of the first embodiment. Furthermore, the vertical movement control unit 22A calculates the longitudinal-induced vertical movement torque Tud ＦＲ , and left-right originating vertical torque Tud ＬＲ Using the weight coefficients, the left vertical movement torque Tud is calculated as follows. Ｌ and upward and downward moving torque Tud Ｒ Calculate.

[0050] Tud Ｒ =Tud Ｌ = W ＦＲ x Tud ＦＲ +W ＬＲ x Tud ＬＲ ... (Equation 14) W ＦＲ +W ＬＲ = 1 ... (Equation 15)

[0051] In equation 14, the weight coefficient W ＦＲ and W ＬＲ These are values ​​between 0 and 1, which sum to 1 as shown in equation 15. Weight coefficient W ＦＲ and W ＬＲ This can be described as a priority value indicating whether to prioritize the forward / backward direction or the left / right direction. Weight coefficient W ＦＲ and W ＬＲ In this embodiment, these are set to predetermined values, for example, both to 0.5.

[0052] According to the second embodiment described above, the following effects can be obtained. (5) The front wheels 8F include the left front wheel 8FL and the right front wheel 8FR. The rear wheels 8R include the left rear wheel 8RL and the right rear wheel 8RR. The vehicle 1 is capable of independently controlling all four wheels. The vertical motion control unit 22A calculates the acceleration of the controlled position using the outputs of the left front wheel acceleration sensor 3FL, the right front wheel acceleration sensor 3FR, the left rear wheel acceleration sensor 3RL, and the right rear wheel acceleration sensor 3RR, the longitudinal position of the vehicle at the controlled position, and the lateral position of the vehicle at the controlled position, and determines the braking force using the acceleration of the controlled position. Therefore, the vertical motion control unit 22A can also suppress vertical vibrations caused by lateral vibrations.

[0053] (6) The vertical movement control unit 22A determines the priority between the reaction force of the braking and driving force in the longitudinal direction of the vehicle 1A and the reaction force of the braking and driving force in the lateral direction of the vehicle, i.e., the weighting coefficient W. ＦＲ and W ＬＲ This can be set. Therefore, the vertical movement control unit 22A can select the direction in which the reaction force is generated.

[0054] (Modification 1 of the second embodiment) In the second embodiment described above, the longitudinal and lateral directions of the vehicle 1 were treated similarly. However, the priority order of vibration damping may be changed. Whether to prioritize the longitudinal or lateral direction, or in other words, which direction to prioritize, may be set in advance by the user or changed according to the situation. The latter case will be explained in detail.

[0055] The first example is a method for determining the preferred direction using road surface conditions. In this case, the vehicle 1 has means for detecting road surface conditions, such as a camera or laser scanner and a data processing mechanism, and the vertical motion control unit 22A determines the preferred direction according to the detected road surface conditions. If unevenness is detected in the road surface in the longitudinal direction, such as at the connection point of a bridge pier or a bump, vibration damping in the longitudinal direction is prioritized. Also, if one wheel falls into a rut in the road surface, the left-right direction is prioritized.

[0056] According to this first example, the following effects can be obtained: (7) The vehicle 1A is equipped with a sensor that detects the condition of the road surface. The vertical movement control unit 22A sets the priority using the output of the sensor.

[0057] The second example is a method for determining the priority direction based on the motion of vehicle 1A. For example, if the motion of vehicle 1A is mainly acceleration or deceleration, the priority of the longitudinal direction is set higher, and if the motion of vehicle 1A is mainly turning, the priority of the lateral direction is set higher. When vehicle 1A experiences pitching motion during acceleration or deceleration, the longitudinal direction is prioritized to suppress vertical vibrations caused by the pitching motion. When vehicle 1A experiences rolling motion during turning, the lateral direction is prioritized to suppress lateral vibrations. The operation information input unit 21A also inputs operation data for the accelerator pedal, brake pedal, and steering wheel to the vertical motion control unit 22A, allowing the vertical motion control unit 22A to determine the motion of vehicle 1A. However, the vertical motion control unit 22A may also determine the motion of vehicle 1A using sensors not shown, such as the output of an accelerometer that measures the acceleration of vehicle 1A in the longitudinal and lateral directions, or images captured by a camera that photographs the area around vehicle 1A.

[0058] According to this second example, the following effects can be obtained: (8) The vertical motion control unit 22A sets the priority so that the reaction force of the braking and driving force in the longitudinal direction of the vehicle 1A is large when the motion of the vehicle 1A is mainly acceleration and deceleration, and sets the priority so that the reaction force of the braking and driving force in the lateral direction of the vehicle 1A is large when the motion of the vehicle 1A is mainly turning.

[0059] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are explained in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, the control lines and information lines shown are those deemed necessary for explanation, and not all control lines and information lines are necessarily shown in the product. In practice, it can be assumed that almost all components are interconnected.

[0060] 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.

[0061] 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 motion 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 motion control device 2 when necessary. Here, the 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.

[0062] 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.

[0063] 1, 1A: Vehicle 2, 2A: Vehicle motion control device 3F: Front wheel acceleration sensor 3FL: Left front wheel acceleration sensor 3FR: Right front wheel acceleration sensor 3R: Rear wheel acceleration sensor 3RL: Left rear wheel acceleration sensor 3RR: Right rear wheel acceleration sensor 21: Operation information input unit 22, 22A: Vertical motion control unit 23, 23A: Acceleration / deceleration torque determination unit 800: Vibration damping target position 800A: Vibration damping target position CGA: Acceleration Fud: Vertical force TF: Front wheel torque command TFL: Left front wheel torque command TFR: Right front wheel torque command TR: Rear wheel torque command TRL: Left rear wheel torque command TRR: Right rear wheel torque command Tud: Vertical motion torque TudL: Left vertical motion torque TudR: Right vertical vertical motion torque P : Crew

Claims

1. A vehicle motion control device for controlling a vehicle, wherein the vehicle comprises front wheels and rear wheels capable of independently controlling braking and driving forces, a front wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the front wheels as front vertical acceleration, and a rear wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the rear wheels as rear vertical acceleration, and further comprises a vertical motion control unit that controls the vertical vehicle motion generated in the vehicle by the reaction force of the braking and driving force, the vertical motion control unit calculates a controlled target position acceleration, which is the vertical acceleration at the controlled target position, using the front vertical acceleration, the rear vertical acceleration, and the longitudinal position of the controlled target position in the vehicle, and determines the braking and driving force using the controlled target position acceleration.

2. A vehicle motion control device according to claim 1, wherein the front wheels include a left front wheel and a right front wheel, the rear wheels include a left rear wheel and a right rear wheel, the vehicle is capable of independently controlling the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel, the front wheel acceleration sensor includes a left front wheel acceleration sensor for measuring the vertical acceleration of the left front wheel and a right front wheel acceleration sensor for measuring the vertical acceleration of the right front wheel, the rear wheel acceleration sensor includes a left rear wheel acceleration sensor for measuring the vertical acceleration of the left rear wheel and a right rear wheel acceleration sensor for measuring the vertical acceleration of the right rear wheel, and the vertical motion control unit calculates the controlled target position acceleration using the outputs of the left front wheel acceleration sensor, the right front wheel acceleration sensor, the left rear wheel acceleration sensor, and the right rear wheel acceleration sensor, the longitudinal position of the controlled target position in the vehicle, and the lateral position of the controlled target position in the vehicle, and determines the braking force using the controlled target position acceleration.

3. A vehicle motion control device according to claim 1, wherein the controlled position is the position of an occupant riding in the vehicle.

4. A vehicle motion control device according to claim 3, wherein the vertical motion control unit identifies the control target position using the output of a sensor mounted on the vehicle or position information of a device held by the occupant.

5. A vehicle motion control device according to claim 2, wherein the vertical motion control unit is capable of setting the priority between the reaction force of the braking and driving force in the longitudinal direction of the vehicle and the reaction force of the braking and driving force in the lateral direction of the vehicle.

6. A vehicle motion control device according to claim 1, wherein the vertical motion control unit controls the vertical acceleration at the controlled position to be reduced.

7. A vehicle motion control device according to claim 5, wherein the vehicle further comprises a sensor for detecting the condition of the road surface, and the vertical motion control unit sets the priority using the output of the sensor.

8. A vehicle motion control device according to claim 5, wherein the vertical motion control unit sets the priority so that the reaction force of the braking and driving force in the longitudinal direction of the vehicle is large when the motion of the vehicle is mainly acceleration and deceleration, and sets the priority so that the reaction force of the braking and driving force in the lateral direction of the vehicle is large when the motion of the vehicle is mainly turning.

9. A vehicle motion control method performed by a computer on a vehicle, wherein the vehicle comprises front wheels and rear wheels capable of independently controlling braking and driving forces, a front wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the front wheels as front vertical acceleration, and a rear wheel acceleration sensor that measures the vertical acceleration of the vehicle at the position of the rear wheels as rear vertical acceleration, and includes a vertical motion control step for controlling the vertical vehicle motion generated in the vehicle by the reaction force of the braking and driving force, wherein the vertical motion control step calculates a controlled target position acceleration, which is the acceleration at the controlled target position, using the front vertical acceleration, the rear vertical acceleration, and the longitudinal position of the controlled target position in the vehicle, and determines the braking and driving force using the controlled target position acceleration.

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