JP2022085317A - Control device of vehicle and control program of vehicle - Google Patents

Abstract

To suppress nose lift generated in the start of a vehicle.SOLUTION: A control device 10 is applied to a vehicle configured such that the first force being one force of the anti-dive force and the rear wheel anti-lift force becomes greater than the second force being the other force when the front wheel brake force is the same as the rear wheel brake force. The vehicle includes a braking device 80 which can adjust the front wheel brake force and the rear wheel brake force respectively. The control device 10 includes a braking control unit 12 which controls the braking device 80. The braking control unit 12 operates the braking device 80 so as to increase a ratio of occupation of the brake force applied to main brake wheels out of the brake force applied to the vehicle with the wheels that generate the second force in the vehicle with application of the brake force as the main brake wheels when the vehicle is stopped.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle control device for controlling the posture of the vehicle at the time of starting and a vehicle control program.

Patent Document 1 discloses a control device that adjusts the front-rear distribution ratio of braking force so that the pitch angle of a vehicle approaches a target pitch angle. The front-rear distribution ratio indicates the ratio of the braking force of the vehicle distributed to the braking force applied to the front wheels and the braking force applied to the rear wheels.

Japanese Unexamined Patent Publication No. 2019-77221

When the vehicle is started from a stopped state, the behavior of displacing the front part of the vehicle upward and the rear part of the vehicle downward, that is, nose lift is likely to occur. If a nose lift occurs at the time of starting, the speed of change of the pitch angle of the vehicle may be large. Therefore, as in the control device disclosed in Patent Document 1, control that eliminates the discrepancy between the pitch angle of the vehicle and the target pitch angle by adjusting the front-rear distribution ratio is sufficient for the nose lift generated at the time of starting. It was sometimes difficult to control.

The vehicle control device for solving the above problems is a vehicle having a braking device capable of separately adjusting the braking force applied to the front wheels of the wheels and the braking force applied to the rear wheels of the wheels. When a braking force is applied to, an anti-dive force is generated, which is a force that displaces the front part of the vehicle upward, and when a braking force is applied to the rear wheels, a rear wheel, which is a force that displaces the rear part of the vehicle downward. When an anti-lift force is generated and the braking force applied to the front wheels and the braking force applied to the rear wheels are of the same magnitude, the anti-dive force and the rear wheel anti-lift force The braking control unit is provided with a braking control unit that is applied to a vehicle configured so that the first force, which is one of the forces, is larger than the second force, which is the other force, and controls the braking device. When the vehicle is stopped, the unit applies the wheel that generates the second force to the vehicle by applying the braking force as the main braking wheel, and applies the braking force applied to the vehicle to the main braking wheel. The gist is to operate the braking device so as to increase the ratio of the braking force to be applied.

According to the above configuration, for example, in a vehicle in which the rear wheel anti-lift force is larger than the anti-dive force, the ratio of the braking force applied to the front wheels while the vehicle is stopped is increased. Further, for example, in a vehicle in which the anti-dive force is larger than the rear wheel anti-lift force, the ratio of the braking force applied to the rear wheels while the vehicle is stopped is increased. This is a moment generated when the vehicle is started, and it is possible to reduce the moment that causes the posture of the vehicle to be a nose lift. That is, by adjusting the ratio of the braking force in the front and rear wheels, it is possible to make it difficult to generate a nose lift when starting the vehicle.

The schematic diagram which shows one Embodiment of the control device of a vehicle, and the vehicle which is the control target of the control device. The schematic diagram explaining the force acting on a vehicle by a braking force, and the force acting on a vehicle by a driving force. A flowchart showing the flow of processing executed by the control device, taking as an example a vehicle in which the rear wheel anti-lift force is larger than the anti-dive force. A timing chart showing the braking force and driving force when starting the vehicle.

Hereinafter, an embodiment of the vehicle control device will be described with reference to FIGS. 1 to 4.
FIG. 1 shows a vehicle 90 equipped with a first motor generator 71F and a second motor generator 71R as power sources. The first motor generator 71F and the second motor generator 71R constitute a drive device for the vehicle 90.

The vehicle 90 is equipped with four wheels. The vehicle 90 includes a left front wheel FL and a right front wheel FR as front wheels. The vehicle 90 includes a front wheel axle 73F to which a left front wheel FL and a right front wheel FR are attached. The vehicle 90 includes a left rear wheel RL and a right rear wheel RR as rear wheels. The vehicle 90 includes a rear wheel axle 73R to which a left rear wheel RL and a right rear wheel RR are attached.

The vehicle 90 is a four-wheel drive vehicle. The driving force output from the first motor generator 71F is transmitted to the front wheels FL and FR via the front wheel axle 73F. The driving force output from the second motor generator 71R is transmitted to the rear wheels RL and RR via the rear wheel axle 73R. In the vehicle 90, the driving force can be distributed to the front wheels FL and FR and the rear wheels RL and RR.

The vehicle 90 includes a suspension device that suspends the wheels. The vehicle 90 includes a suspension device for the front wheels FL and FR attached to the left front wheel FL and the right front wheel FR. The vehicle 90 includes a suspension device for the rear wheels RL and RR attached to the left rear wheel RL and the right rear wheel RR.

The vehicle 90 includes a braking operation member 61. The braking operation member 61 is attached at a position where the driver of the vehicle can operate the braking operation member 61. The braking operation member 61 is, for example, a brake pedal.

The vehicle 90 is provided with a braking device 80 that applies a braking force to the wheels. The braking device 80 includes a braking mechanism 84 corresponding to each wheel. The braking mechanism 84 is composed of a rotating body 87 that rotates integrally with the wheel, a friction material 86, and a wheel cylinder 85. In the braking mechanism 84, the friction material 86 is pressed against the rotating body 87 according to the hydraulic pressure in the wheel cylinder 85. The braking mechanism 84 can increase the braking force applied to the wheels as the force for pressing the friction material 86 against the rotating body 87 increases.

The braking device 80 includes a hydraulic pressure generating device 81 and a braking actuator 83. The braking device 80 can supply the hydraulic pressure generated by the hydraulic pressure generator 81 to the wheel cylinder 85 via the braking actuator 83.

The hydraulic pressure generator 81 can generate hydraulic pressure according to the amount of operation when the braking operation member 61 is operated by the driver. When the driver is operating the braking operation member 61, an amount of brake fluid corresponding to the hydraulic pressure generated by the hydraulic pressure generator 81 is supplied to the wheel cylinder 85 via the braking actuator 83.

The braking actuator 83 can individually adjust the hydraulic pressure supplied to each wheel cylinder 85. That is, the braking device 80 can adjust the braking force applied to each wheel separately.

FIG. 2 shows the vehicle 90 as seen from the side. FIG. 2 illustrates the left front wheel FL and the left rear wheel RL among the wheels. FIG. 2 shows the vehicle center of gravity GC of the vehicle 90. FIG. 2 shows the center of gravity height H, which is the distance from the vehicle center of gravity GC to the road surface. In FIG. 2, the horizontal distance between the vehicle center of gravity GC and the front wheel axle 73F in the front-rear direction of the vehicle 90 is displayed as the first distance Lf. In FIG. 2, the horizontal distance between the vehicle center of gravity GC and the rear wheel axle 73R in the front-rear direction of the vehicle 90 is displayed as the second distance Lr. The sum of the first distance Lf and the second distance Lr corresponds to the wheelbase of the vehicle 90.

In FIG. 2, the inertial force Fi acting on the vehicle center of gravity GC when the vehicle 90 in the stopped state is started is indicated by a white arrow. When starting the vehicle 90, a backward inertial force Fi acts on the vehicle center of gravity GC.

FIG. 2 shows an arrow illustrating the pitching moment M generated around the center of gravity of the vehicle GC when the vehicle 90 is started. The pitching moment M can be calculated based on the inertial force Fi acting on the vehicle center of gravity GC, the height H of the center of gravity of the vehicle 90, the first distance Lf, and the second distance Lr. The pitching moment M is a force that causes the vehicle body front portion 91F, which is a portion of the vehicle body 91 on the front wheels FL and FR sides, to be displaced upward. The pitching moment M is a force that causes the vehicle body rear portion 91R, which is a portion of the vehicle body 91 on the rear wheel RL and RR sides, to be displaced downward. That is, the pitching moment M is a force that makes the vehicle 90 a nose lift.

Hereinafter, in the description with reference to FIG. 2, the left front wheel FL may be described, and the description of the right front wheel FR symmetrical with respect to the left front wheel FL may be omitted. Similarly, the description of the left rear wheel RL may be described, and the description of the right rear wheel RR symmetrical with respect to the left rear wheel RL may be omitted.

The braking force and the driving force acting on each wheel of the vehicle 90 will be described. In FIG. 2, the braking force acting on the front wheels FL and FR is displayed as the front wheel braking force BFf. The driving force acting on the front wheels FL and FR is indicated as the front wheel driving force DFf. In FIG. 2, the braking force acting on the rear wheels RL and RR is displayed as the rear wheel braking force BFr. The driving force acting on the rear wheel RL and RR is indicated as the rear wheel driving force DFr. The sum of the front wheel braking force BFf and the rear wheel braking force BFr is called the total braking force of the vehicle 90. The sum of the front wheel drive force DFf and the rear wheel drive force DFr is called the total drive force of the vehicle 90.

FIG. 2 shows the instantaneous center of rotation of the wheel. The instantaneous center of rotation of the front wheels FL and FR during braking is displayed as the first center of rotation Cfb. The angle formed by the straight line connecting the point where the front wheel FL and the road surface are in contact with the first rotation center Cfb and the road surface is displayed as the first angle θf. The instantaneous center of rotation of the front wheel FL during driving is displayed as the second center of rotation Cfd. The angle formed by the straight line connecting the point where the front wheel FL and the road surface are in contact with the second rotation center Cfd and the road surface is displayed as the second angle φf. Further, the instantaneous rotation center of the rear wheel RL during braking is displayed as the third rotation center Crb. The angle formed by the straight line connecting the point where the rear wheel RL and the road surface are in contact with the third rotation center Crb and the road surface is displayed as the third angle θr. The instantaneous rotation center of the rear wheel RL during driving is displayed as the fourth rotation center Crd. The angle formed by the straight line connecting the point where the rear wheel RL and the road surface are in contact with the fourth rotation center Crd and the road surface is indicated as the fourth angle φr.

The position of the center of rotation at each moment is determined by the characteristics of the suspension device. The position of each instantaneous rotation center shown in FIG. 2 is an example and does not represent the actual position of the instantaneous rotation center. Therefore, the magnitudes of the first angle θf, the second angle φf, the third angle θr, and the fourth angle φr do not indicate the actual magnitude of the angle.

The force for changing the posture of the vehicle 90 will be described with reference to FIG. In FIG. 2, the anti-dive force FbAD and the front wheel anti-lift force FdAL are indicated by white arrows as the forces acting on the vehicle 90 by the suspension devices for the front wheels FL and FR. In FIG. 2, the anti-squart force FdAS and the rear wheel anti-lift force FbAL are indicated by white arrows as the forces acting on the vehicle 90 by the suspension devices for the rear wheels RL and RR. The white arrow indicates the direction of the force and does not indicate the actual magnitude of the force.

The anti-dive force FbAD will be described. The anti-dive force FbAD is a force acting by applying a braking force to the front wheels FL and FR. The anti-dive force FbAD is a force that suppresses the sinking of the front portion 91F of the vehicle body. The direction in which the anti-dive force FbAD acts is a direction in which the front portion of the vehicle is displaced so as to be separated from the road surface.

The front wheel anti-lift force FdAL will be described. The front wheel anti-lift force FdAL is a force acting by transmitting a driving force to the front wheels FL and FR. The front wheel anti-lift force FdAL is a force that suppresses the front portion 91F of the vehicle body from rising. The direction in which the front wheel anti-lift force FdAL acts is the direction in which the front portion of the vehicle is displaced so as to approach the road surface.

The rear wheel anti-lift force FbAL will be described. The rear wheel anti-lift force FbAL is a force that acts by applying a braking force to the rear wheels RL and RR. The rear wheel anti-lift force FbAL is a force that suppresses the rear portion 91R of the vehicle body from rising. The direction in which the rear wheel anti-lift force FbAL acts is the direction in which the rear portion of the vehicle is displaced so as to approach the road surface.

The anti-squart force FdAS will be described. The anti-squart force FdAS is a force that acts by transmitting a driving force to the rear wheels RL and RR. The anti-squart force FdAS is a force that suppresses the sinking of the rear portion 91R of the vehicle body. The direction in which the anti-squart force FdAS acts is the direction in which the rear part of the vehicle is displaced so as to be separated from the road surface.

The anti-dive force FbAD can be expressed as the following relational expression (Equation 1) by using the front wheel braking force BFf and the first angle θf. The front wheel anti-lift force FdAL can be expressed as the following relational expression (Equation 2) by using the front wheel drive force DFf and the second angle φf.

FbAD = BFf · tanθf ... (Equation 1)
FdAL = DFf ・ tanφf ... (Equation 2)
As shown in the relational expression (Equation 1), the anti-dive force FbAD becomes larger as the front wheel braking force BFf is larger. The anti-dive force FbAD becomes larger as the tan θf based on the first angle θf is larger. As shown in the relational expression (Equation 2), the front wheel anti-lift force FdAL becomes larger as the front wheel driving force DFf is larger. The front wheel anti-lift force FdAL becomes larger as the tan φf based on the second angle φf is larger.

The rear wheel anti-lift force FbAL can be expressed as the following relational expression (Equation 3) by using the rear wheel braking force BFr and the third angle θr. The anti-squart force FdAS can be expressed as the following relational expression (Equation 4) by using the rear wheel driving force DFr and the fourth angle φr.

FbAL = BFr · tanθr ... (Equation 3)
FdAS = DFr · tanφr ... (Equation 4)
As shown in the relational expression (Equation 3), the rear wheel anti-lift force FbAL becomes larger as the rear wheel braking force BFr is larger. The rear wheel anti-lift force FbAL becomes larger as the tan θr based on the third angle θr is larger. As shown in the relational expression (Equation 4), the anti-squart force FdAS becomes larger as the rear wheel driving force DFr is larger. The anti-squart force FdAS becomes larger as the tanφr based on the fourth angle φr is larger.

In the vehicle suspension system, when the front wheel braking force BFf and the rear wheel braking force BFr have the same magnitude, one of the anti-dive force FbAD and the rear wheel anti-lift force FbAL is larger than the other force. The suspension geometry is set so that it becomes. In the suspension device for front wheels FL and FR and the suspension device for rear wheels RL and RR provided in the vehicle 90, when the front wheel braking force BFf and the rear wheel braking force BFr have the same magnitude, the anti-dive force FbAD The suspension geometry is set so that the rear wheel anti-lift force FbAL is larger. That is, the suspension geometry is set so that the relationship in which the third angle θr is larger than the first angle θf is established.

In the suspension system of a vehicle, when the front wheel drive force DFf and the rear wheel drive force DFr have the same magnitude, one of the anti-squart force FdAS is larger than the front wheel anti-lift force FdAL and the other force is larger than the other force. The suspension geometry is set so that it becomes. In the suspension device for front wheels FL and FR and the suspension device for rear wheels RL and RR provided in the vehicle 90, when the front wheel drive force DFf and the rear wheel drive force DFr have the same magnitude, the front wheel anti-lift force FdAL The suspension geometry is set so that the anti-squart force FdAS is larger than that. That is, the suspension geometry is set so that the relationship in which the fourth angle φr is larger than the second angle φf is established.

The equation of motion for pitching the vehicle 90 can be expressed as the following relational expression (Equation 5).
Iy ・ θy ″ = {(BFf + BFr)-(DFf + DFr)} ・ H-FbAD ・ Lf-FbAL ・ Lr + FdAL ・ Lf + FdAS ・ Lr ... (Equation 5)
"Iy" in the relational expression (Equation 5) represents the pitch moment of inertia. “Θy ″” in the relational expression (Equation 5) represents the second derivative value of the pitch angle θy. That is, "θy""represents the pitch angular acceleration.

As described above, in the vehicle 90, the anti-dive force FbAD and the rear wheel anti-lift force FbAL acting on the vehicle 90 can be adjusted by adjusting the front wheel braking force BFf and the rear wheel braking force BFr. The anti-dive force FbAD and the rear wheel anti-lift force FbAL are forces acting in the direction of increasing the pitching moment M. The pitching moment M can be adjusted by adjusting the front wheel braking force BFf and the rear wheel braking force BFr.

Further, in the vehicle 90, the front wheel anti-lift force FdAL and the anti-quart force FdAS acting on the vehicle 90 can be adjusted by adjusting the front wheel drive force DFf and the rear wheel drive force DFr. The front wheel anti-lift force FdAL and the anti-squart force FdAS are forces acting in a direction of suppressing the pitching moment M. The pitching moment M can be adjusted by adjusting the front wheel drive force DFf and the rear wheel drive force DFr.

The vehicle 90 shown in FIG. 1 is provided with various sensors. FIG. 1 shows a brake sensor 21, an accelerator sensor 22, and a wheel speed sensor 23 as examples of various sensors. The detection signals from the various sensors are input to the control device 10 included in the vehicle 90.

The brake sensor 21 can detect the amount of operation of the braking operation member 61. The brake sensor 21 may be a sensor that detects the pressure applied to the braking operation member 61 in order to operate the braking operation member 61.

The accelerator sensor 22 can detect the amount of operation of the drive operation member. The drive operating member is, for example, an accelerator pedal.
The wheel speed sensor 23 is attached to each wheel included in the vehicle 90. The wheel speed sensor 23 can detect the wheel speed of each wheel.

The vehicle 90 may include an information acquisition device 30. The information acquisition device 30 has a function of acquiring information about the periphery of the vehicle 90. The information acquisition device 30 can output the obtained information to the control device 10. An example of the information acquisition device 30 includes a camera that captures an image of the periphery of the vehicle 90. The information acquisition device 30 includes an information processing unit that processes an image captured by the camera. For example, the information acquisition device 30 can calculate the distance between the vehicle located in front of the vehicle 90 and the vehicle 90 by analyzing the captured image in the information processing unit.

The information acquisition device 30 may include a millimeter-wave radar, LIDAR, sonar, or the like as a device other than the camera. Based on the information detected by these devices, the information acquisition device 30 can also calculate the distance between the vehicle located in front of the vehicle 90 and the vehicle 90.

The information acquisition device 30 may have a function of identifying a display of a traffic signal existing in the traveling direction of the vehicle 90.
The information acquisition device 30 may include a receiving device that receives information transmitted from a traffic signal. The information includes information indicating the display of a traffic signal. The receiving device is not limited to the traffic signal, and may have a function of receiving information transmitted from a transmitting device installed on the road.

The vehicle 90 includes a control device 10. The control device 10 controls the first motor generator 71F and the second motor generator 71R. That is, the control device 10 controls the drive device. The control device 10 controls the braking device 80. The control device 10 includes a CPU and a ROM. The ROM of the control device 10 stores various programs for the CPU to execute various controls.

The control device 10 is composed of a plurality of functional units that execute various controls. FIG. 1 shows an acquisition unit 11, a braking control unit 12, a drive control unit 13, and a start prediction unit 14 as an example of the functional unit.

The acquisition unit 11 refers to the signals output by the various sensors. The acquisition unit 11 can calculate the operation amount of the braking operation member 61 based on the output signal of the brake sensor 21. The acquisition unit 11 can calculate a target value of the total braking force of the vehicle 90 based on the operation amount of the braking operation member 61. The acquisition unit 11 can calculate the operation amount of the drive operation member based on the output signal of the accelerator sensor 22. The acquisition unit 11 can calculate a target value of the total driving force of the vehicle 90 based on the operation amount of the drive operating member. The acquisition unit 11 can calculate the wheel speed of each wheel based on the output signal of the wheel speed sensor 23. The acquisition unit 11 can calculate the vehicle speed based on the wheel speed.

The acquisition unit 11 can also refer to the information output by the information acquisition device 30. The acquisition unit 11 may acquire the distance between the vehicle located in front of the vehicle 90 and the vehicle 90. The acquisition unit 11 may acquire the state of the traffic signal located in front of the vehicle 90.

The braking control unit 12 can apply a braking force to the wheels of the vehicle 90 by operating the braking device 80. The braking control unit 12 can adjust the front wheel braking force BFf and the rear wheel braking force BFr separately.

The braking control unit 12 has a function of setting a braking force distribution ratio. The braking force distribution ratio is a ratio of distributing the braking force applied to the vehicle 90 when braking the vehicle 90 to the braking force applied to the front wheels FL and FR and the braking force applied to the rear wheels RL and RR. That is, the braking force distribution ratio is a ratio that distributes the total braking force of the vehicle 90 to the front wheel braking force BFf and the rear wheel braking force BFr. The braking control unit 12 can adjust the ratio of the front wheel braking force BFf and the rear wheel braking force BFr based on the braking force distribution ratio. The braking control unit 12 stores a basic braking force ratio as a reference value for adjusting the braking force distribution ratio. The basic braking force ratio is a value of the braking force distribution ratio when the control for adjusting the braking force distribution ratio does not intervene. As an example, the basic braking force ratio is the front wheel braking force BFf and the rear wheel control in the braking force applied by the braking device 80 in response to the operation of the braking operation member 61 when the control for adjusting the braking force distribution ratio does not intervene. The ratio with the power BFr is shown. The control for adjusting the braking force distribution ratio is not limited to the control exemplified in this embodiment.

The braking force distribution ratio will be further described. For example, when the ratio of the front wheel braking force BFf to the braking force distribution ratio is increased while the target value of the total braking force is maintained constant, the front wheel braking force BFf is increased and the rear wheel braking force BFr is decreased. .. For example, when the ratio of the rear wheel braking force BFr to the braking force distribution ratio is increased while the target value of the total braking force is maintained constant, the rear wheel braking force BFr is increased and the front wheel braking force BFf is decreased. To. For example, when the target value of the total braking force is increased or decreased while the braking force distribution ratio is kept constant, the total braking force after the fluctuation is the front wheel braking force BFf and the rear wheel braking force according to the braking force distribution ratio. The front wheel braking force BFf and the rear wheel braking force BFr are adjusted so as to be distributed to the BFr.

The drive control unit 13 may have a function of setting the drive force distribution ratio. The driving force distribution ratio is a ratio of distributing the driving force of the vehicle 90 to the driving force applied to the front wheels FL and FR and the driving force applied to the rear wheels RL and RR. That is, the driving force distribution ratio is a ratio in which the total driving force of the vehicle 90 is distributed to the front wheel driving force DFf and the rear wheel driving force DFr. The drive control unit 13 stores a basic drive force ratio as a reference value for adjusting the drive force distribution ratio. The basic driving force ratio is a value of the driving force distribution ratio when the control for adjusting the driving force distribution ratio does not intervene. The control for adjusting the driving force distribution ratio is not limited to the control exemplified in this embodiment.

The drive control unit 13 can transmit the drive force to the wheels of the vehicle 90 by operating the drive device. The drive control unit 13 controls the first motor generator 71F by operating the inverter of the first motor generator 71F. The drive control unit 13 can transmit the front wheel drive force DFf to the front wheels FL and FR by controlling the first motor generator 71F. The drive control unit 13 controls the second motor generator 71R by operating the inverter of the second motor generator 71R. The drive control unit 13 can transmit the rear wheel drive force DFr to the rear wheels RL and RR by controlling the second motor generator 71R. The drive control unit 13 can also adjust the ratio of the front wheel drive force DFf and the rear wheel drive force DFr based on the drive force distribution ratio.

The driving force distribution ratio will be further described. For example, when the ratio of the front wheel drive force DFf to the drive force distribution ratio is increased while the target value of the total drive force is maintained constant, the front wheel drive force DFf is increased and the rear wheel drive force DFr is decreased. .. For example, when the ratio of the rear wheel driving force DFr to the driving force distribution ratio is increased while the target value of the total driving force is maintained constant, the rear wheel driving force DFr is increased and the front wheel driving force DFf is decreased. To. For example, when the target value of the total driving force is increased or decreased while the driving force distribution ratio is kept constant, the total driving force after the fluctuation increases the front wheel driving force DFf and the rear wheel driving force according to the driving force distribution ratio. The front wheel drive force DFf and the rear wheel drive force DFr are adjusted so as to be distributed to the DFr.

The start prediction unit 14 can predict when the stopped vehicle 90 will start. For example, the start prediction unit 14 can predict that the vehicle 90 will start when the distance between the vehicle located in front of the vehicle 90 and the vehicle 90 increases. For example, the start prediction unit 14 can predict that the vehicle 90 will start based on the state of the traffic signal located in front of the vehicle 90.

The control device 10 executes a process for controlling the start of the vehicle 90. In the start control, the pitching moment M when starting the vehicle 90 can be controlled by adjusting the front wheel braking force BFf and the rear wheel braking force BFr while the vehicle 90 is stopped. In the start control, the pitching moment M can be controlled by adjusting the driving force distribution ratio when the vehicle 90 is started. Hereinafter, this process will be described with reference to FIG. The ROM included in the control device 10 stores a control program, which is a program for executing the process shown in FIG. The process shown in FIG. 3 is realized by the CPU executing the control program stored in the ROM.

FIG. 3 shows a flow of processing executed by the control device 10. This processing routine is repeatedly executed at predetermined intervals.
When the processing routine is started, first, in step S101, the control device 10 determines whether or not the vehicle 90 is in the stopped state. For example, when the vehicle speed of the vehicle 90 is "0", it can be determined that the vehicle 90 is in the stopped state. Further, for example, when the rotation of the wheels is stopped, it can be determined that the vehicle 90 is in the stopped state.

When the vehicle 90 is not in the stopped state (S101: NO), the control device 10 temporarily ends the processing routine. On the other hand, when the vehicle 90 is in the stopped state (S101: YES), the control device 10 shifts the process to step S102.

In step S102, the control device 10 determines whether or not the start condition of the start control is satisfied. An example of the start condition of the start control will be described. For example, the control device 10 determines that the start condition is satisfied when a predetermined time has elapsed after the vehicle 90 has stopped. For example, the control device 10 can also determine that the start condition is satisfied when the start of the vehicle 90 is predicted by the start prediction unit 14. Further, the control device 10 may determine that the start condition is not satisfied when the specified period cannot be secured by the time when the vehicle 90 is predicted to start. The specified period is a period for adjusting the front wheel braking force BFf and the rear wheel braking force BFr while the vehicle 90 is stopped. For the specified period, a value calculated in advance by an experiment or the like can be used.

In the process of step S102, if the start condition of the start control is not satisfied (S102: NO), the control device 10 temporarily ends the process routine. On the other hand, when the start condition of the start control is satisfied (S102: YES), the control device 10 shifts the process to step S103.

In step S103, the control device 10 causes the drive control unit 13 to set the drive force distribution ratio when starting the vehicle 90. The suspension geometry of the drive control unit 13 is set so that the anti-square force FdAS is larger than the front wheel anti-lift force FdAL when the front wheel drive force DFf and the rear wheel drive force DFr have the same magnitude. In the vehicle 90, the driving force distribution ratio is set so that the ratio of the rear wheel driving force DFr becomes large. That is, the drive control unit 13 sets the drive force distribution ratio so that the ratio of the rear wheel drive force DFr that generates the anti-squart force FdAS becomes large. For example, the drive control unit 13 sets the drive force distribution ratio to a value in which the ratio of the rear wheel drive force DFr is larger than the basic drive force ratio. The drive control unit 13 can also set the drive force distribution ratio so that the total drive force of the vehicle 90 is satisfied by the rear wheel drive force DFr. That is, the drive control unit 13 may transmit the drive force only to the rear wheels RL and RR. When starting the vehicle 90, the drive control unit 13 operates the drive device according to the drive force distribution ratio set in the process of step S103. As a result, the driving force is transmitted so that the rear wheel driving force DFr becomes larger than when the driving force distribution ratio is the basic driving force ratio.

When the driving force distribution ratio is set by the process of step S103, the control device 10 shifts the process to step S104.
In step S104, the control device 10 causes the braking control unit 12 to execute the process of increasing the front wheel braking force BFf. The braking control unit 12 operates the braking device 80 so as to increase the front wheel braking force BFf while maintaining the rear wheel braking force BFr constant. That is, the total braking force is increased by increasing the front wheel braking force BFf. In other words, the braking control unit 12 increases the total braking force. The braking force distribution ratio when increasing the total braking force is set so that the ratio of the front wheel braking force BFf is increased while maintaining the magnitude of the rear wheel braking force BFr. In this way, the braking control unit 12 increases the ratio of the front wheel braking force BFf to the total braking force applied to the vehicle 90.

In the process of increasing the front wheel braking force BFf, the braking control unit 12 increases the front wheel braking force BFf until the front wheel braking force BFf reaches the holding braking force. The holding braking force is calculated in advance as the magnitude of the front wheel braking force BFf that can hold the vehicle 90 in a stopped state even when the rear wheel braking force BFr is "0". When the braking control unit 12 is made to execute the process of increasing the front wheel braking force BFf, the control device 10 shifts the process to step S105.

In step S105, the control device 10 executes the standby process. When the control device 10 finishes the standby process, the control device 10 shifts the process to step S106. For example, the control device 10 ends the standby process when a predetermined standby time elapses after the front wheel braking force BFf reaches the holding braking force.

In step S106, the control device 10 causes the braking control unit 12 to execute the process of reducing the rear wheel braking force BFr. The braking control unit 12 operates the braking device 80 so as to reduce the rear wheel braking force BFr while maintaining the front wheel braking force BFf constant. The braking control unit 12 reduces the rear wheel braking force BFr until the rear wheel braking force BFr becomes “0”. The braking control unit 12 may control the decreasing speed of the rear wheel braking force BFr so that the rear wheel braking force BFr becomes "0" by the time the vehicle 90 starts. When the braking control unit 12 is made to execute the rear wheel braking force BFr reduction processing, the control device 10 ends the processing routine.

The operation and effect of this embodiment will be described.
FIG. 4 shows the transition of the braking force and the transition of the driving force when the vehicle 90 is started. In the example shown in FIG. 4, the braking force is reduced to “0” at the timing t16 as shown in FIG. 4 (a). The reduction of the braking force is started from the timing t15 before the timing t16. As shown in FIG. 4B, the driving force is increased after the timing t15. The timing t15 is the time when the vehicle 90 is started. Further, it is assumed that the start condition of the start control is satisfied at the timing t11.

In the example shown in FIG. 4, the period before the timing t15 is the stop period P1 in which the vehicle 90 is stopped. The period from the timing t15 to the timing t16 is the start period P2. The starting period P2 is a period in which the driving force of the vehicle 90 is increased and the braking force is decreased. The period after the timing t16 is the acceleration period P3 after the braking force is reduced to "0".

In FIG. 4A, the front wheel braking force BFf is indicated by a solid line. In FIG. 4A, the rear wheel braking force BFr is indicated by a broken line. As shown in FIG. 4A, the rear wheel braking force BFr is larger than the front wheel braking force BFf in the period before the timing t11 in the stop period P1.

When the start condition of the start control is satisfied at the timing t11, the drive control unit 13 sets the drive force distribution ratio (S103). As a result, the driving force distribution ratio is set so that the ratio of the rear wheel driving force DFr becomes large.

When the start condition of the start control is satisfied at the timing t11, the braking control unit 12 starts the process of increasing the front wheel braking force BFf (S104). Therefore, after the timing t11, the front wheel braking force BFf is increased. On the other hand, the rear wheel braking force BFr is maintained at the value at the time point before the timing t11. That is, in the stop period P1, the ratio of the front wheel braking force BFf to the total braking force applied to the vehicle 90 is increased.

As shown in FIG. 4A, when the front wheel braking force BFf increases to the holding braking force at the timing t12, the process of increasing the front wheel braking force BFf is completed. After that, the front wheel braking force BFf is maintained at the holding braking force until the timing t15 when the vehicle 90 starts.

In the control device 10, when a predetermined waiting time elapses after the front wheel braking force BFf reaches the holding braking force, the rear wheel braking force BFr reduction process is started (S106). In the example shown in FIG. 4, the period from the timing t12 to the timing t13 corresponds to the waiting time.

As shown in FIG. 4A, the rear wheel braking force BFr starts to decrease from the timing t13 after the standby time has elapsed. The rear wheel braking force BFr is reduced to "0" at the timing t14 during the stop period P1. Therefore, in the period from the timing t14 to the timing t15 when the vehicle 90 starts, the rear wheel braking force BFr is "0". In the period from the timing t14 to the timing t15, the total braking force applied to the vehicle 90 by the front wheel braking force BFf is satisfied.

When the vehicle 90 starts from the stopped state, as shown as the starting period P2, there is a period in which the braking force is applied even after the transmission of the driving force is started. In such a starting period P2, the posture of the vehicle 90 is affected by the anti-dive force FbAD and the rear wheel anti-lift force FbAL based on the braking force applied to the vehicle 90.

Therefore, according to the control device 10, the ratio of the front wheel braking force BFf is increased while the vehicle 90 is stopped. Further, the rear wheel braking force BFr is reduced to "0". Here, the vehicle 90 has a suspension geometry such that the rear wheel anti-lift force FbAL is larger than the anti-dive force FbAD when the front wheel braking force BFf and the rear wheel braking force BFr are the same magnitude. It is a set vehicle. Therefore, by increasing the ratio of the front wheel braking force BFf, the rear wheel anti-lift force FbAL, which is a force for suppressing the lifting of the vehicle body rear portion 91R, can be reduced. On the other hand, even if the ratio of the front wheel braking force BFf is increased, the amount of increase in the anti-dive force FbAD can be suppressed to a small amount. This is a moment generated when the vehicle 90 is started, and the pitching moment M that makes the posture of the vehicle 90 a nose lift can be reduced. That is, by adjusting the ratio of the braking force in the front and rear wheels within a possible range, it is possible to make it difficult to generate a nose lift when starting the vehicle 90.

The driving force transmitted to the wheels after the timing t15 is adjusted according to the driving force distribution ratio set by the process of step S103. That is, the rear wheel driving force DFr is larger than when the driving force distribution ratio is the basic driving force ratio. In the acceleration period P3, the driving force distribution ratio may be the basic driving force ratio. Here, in the vehicle 90, the suspension geometry is set so that the anti-square force FdAS is larger than the front wheel anti-lift force FdAL when the front wheel drive force DFf and the rear wheel drive force DFr have the same magnitude. It is a vehicle that has been used. Therefore, by increasing the ratio of the rear wheel driving force DFr, it is possible to increase the anti-squart force FdAS, which is a force for suppressing the sinking of the rear portion 91R of the vehicle body. As a result, the driving force can be transmitted at the time of starting so that the force contrary to the moment that makes the posture of the vehicle 90 a nose lift becomes large. In particular, when the driving force distribution ratio is set so that the total driving force of the vehicle 90 is satisfied by the rear wheel driving force DFr, the posture of the vehicle 90 is nose lifted to the extent possible by adjusting the ratio of the driving force. The force against the pitching moment M can be maximized.

According to the control device 10, the pitching moment M that makes the posture of the vehicle 90 a nose lift can be made smaller by adjusting the ratio of the braking force in the front and rear wheels and the ratio of the driving force in the front and rear wheels.

<Correspondence relationship>
In the present embodiment, the rear wheel anti-lift force FbAL corresponds to the "first force". The anti-dive force FbAD corresponds to the "second force". The front wheels FL and FR correspond to the "main braking wheels".

Further, the anti-squart force FdAS corresponds to the "third force". Front wheel anti-lift force FdAL corresponds to "fourth force". The rear wheels RL and RR correspond to the "main drive wheels".
<Other embodiments>
This embodiment can be modified and implemented as follows. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.

-It is not an essential configuration to reduce the rear wheel braking force BFr to "0" during the stop period P1. It is preferable that the rear wheel braking force BFr is "0" at the time when the vehicle 90 starts, in order to suppress the nose lift. However, even if the rear wheel braking force BFr is not reduced to "0", if the ratio of the front wheel braking force BFf is increased and the ratio of the rear wheel braking force BFr is decreased, the posture of the vehicle 90 is changed to the nose lift. The pitching moment M to be generated can be reduced.

-The process executed in step S103 of FIG. 3 may be omitted. That is, the process of adjusting the driving force distribution ratio can be omitted. Even when the driving force distribution ratio is not adjusted, if the ratio of the front wheel braking force BFf is increased while the vehicle 90 is stopped, the effect of suppressing the nose lift can be obtained.

The control device 10 can also control a vehicle having a suspension geometry different from that of the vehicle 90. In the control device 10, the suspension geometry is set so that the anti-dive force FbAD is larger than the rear wheel anti-lift force FbAL when the front wheel braking force BFf and the rear wheel braking force BFr have the same magnitude. The vehicle may be controlled. In this case, the anti-dive force FbAD corresponds to the "first force". The rear wheel anti-lift force FbAL corresponds to the "second force". Hereinafter, an example in which the vehicle is to be controlled will be described.

In this case, the control device 10 uses the rear wheels RL and RR, which are the wheels that generate the rear wheel anti-lift force FbAL by applying the braking force, as the "main braking wheel". That is, the ratio of the rear wheel braking force BFr is increased while the vehicle 90 is stopped. In an example of the configuration that realizes this control, in step S104 of FIG. 3, the rear wheel braking force BFr increase process is executed instead of the front wheel braking force BFf increase process. Further, in step S106 of FIG. 3, the reduction process of the front wheel braking force BFf is executed instead of the reduction process of the rear wheel braking force BFr. As a result, the anti-dive force FbAD acting when the vehicle 90 starts can be reduced. On the other hand, even if the ratio of the rear wheel braking force BFr is increased, the amount of increase in the rear wheel antilift force FbAL can be suppressed to a small amount. That is, similarly to the above embodiment, the pitching moment M that makes the posture of the vehicle 90 a nose lift can be reduced.

The suspension geometry of the control device 10 is set so that the front wheel antilift force FdAL is larger than the antiquart force FdAS when the front wheel drive force DFf and the rear wheel drive force DFr have the same magnitude. It is also possible to control the vehicle in question. In this case, the front wheel anti-lift force FdAL corresponds to the "third force". The anti-squart force FdAS corresponds to the "fourth force". Hereinafter, an example in which the vehicle is to be controlled will be described.

In this case, the control device 10 uses the front wheels FL and FR, which are wheels that generate the front wheel anti-lift force FdAL by transmitting the driving force, as "main drive wheels". That is, the ratio of the front wheel drive force DFf is increased when the vehicle 90 is started. In an example of the configuration that realizes this control, in the process of step S103 of FIG. 3, the driving force distribution ratio is set so that the ratio of the rear wheel driving force DFr is larger than the basic driving force ratio. As a result, the front wheel anti-lift force FdAL can be increased. That is, as in the above embodiment, the driving force can be transmitted so that the force contrary to the pitching moment M that makes the posture of the vehicle 90 a nose lift becomes large.

-In the above embodiment, a vehicle equipped with a motor generator as a power source is exemplified as a control target of the control device 10. The control device 10 may control a vehicle having an internal combustion engine as a power source. An example of a four-wheel drive vehicle equipped with an internal combustion engine as a power source includes a front differential gear and a rear differential gear. Further, the vehicle is provided with a propeller shaft for connecting the front differential gear and the rear differential gear, and an electronically controlled coupling device. By controlling the electronically controlled coupling device, the control device 10 can adjust the front wheel drive force DFf and the rear wheel drive force DFr according to the drive force distribution ratio.

The vehicle controlled by the control device 10 is not limited to a four-wheel drive vehicle.
A disc brake is exemplified as the braking mechanism 84. The braking mechanism is not limited to the disc brake. For example, a drum brake having a drum as a rotating body and a shoe as a friction material can be adopted.

-In the above embodiment, the information acquisition device 30 includes an information processing unit that processes the acquired information. The control device 10 may include a functional unit having a part or all of the functions corresponding to the information processing unit. Further, the functional unit may be provided in a control device that is different from the control device 10 and is capable of transmitting and receiving information to and from the control device 10.

The information processing unit of the control device 10 and the information acquisition device 30 may have any of the following configurations (a) to (c). (A) One or more processors that execute various processes according to a computer program. The processor includes a CPU and a memory such as RAM and ROM. The memory stores a program code or a command configured to cause the CPU to execute the process. Memory or computer readable media includes any available medium accessible by a general purpose or dedicated computer. (B) One or more dedicated hardware circuits for executing various processes are provided. The dedicated hardware circuit is, for example, an integrated circuit for a specific application, that is, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like. (C) A processor that executes a part of various processes according to a computer program, and a dedicated hardware circuit that executes the remaining processes of the various processes are provided.

The technical idea that can be grasped from the above embodiment and the modified example will be described.
1. 1. It is a vehicle having a braking device capable of separately adjusting the braking force applied to the front wheels of the wheels and the braking force applied to the rear wheels of the wheels, and when the braking force is applied to the front wheels, the front part of the vehicle is moved upward. When an anti-dive force, which is a force that displaces the rear wheels, is generated and a braking force is applied to the rear wheels, a rear wheel anti-lift force, which is a force that displaces the rear part of the vehicle downward, is generated on the front wheels. When the braking force applied to the rear wheels and the braking force applied to the rear wheels are of the same magnitude, the first force, which is one of the anti-dive force and the rear wheel anti-lift force, is the other. It is a vehicle control method that controls a vehicle that is configured to be larger than the second force, which is a force.
The process of controlling the braking device is executed by the vehicle control device.
In the process of controlling the braking device, among the braking forces applied to the vehicle, the wheels that generate the second force in the vehicle by applying the braking force when the vehicle is stopped are used as the main braking wheels. A vehicle control method including a process of operating the braking device so as to increase the proportion of the braking force applied to the main braking wheel.

10 ... Control device 11 ... Acquisition unit 12 ... Braking control unit 13 ... Drive control unit 21 ... Brake sensor 22 ... Accelerator sensor 23 ... Wheel speed sensor 71F ... First motor generator 71R ... Second motor generator 73F ... Front wheel axle 73R ... Rear Wheel axle 80 ... Braking device 84 ... Braking mechanism 90 ... Vehicle 91 ... Car body 91F ... Car body front 91R ... Car body rear

Claims (5)

It is a vehicle having a braking device capable of separately adjusting the braking force applied to the front wheels of the wheels and the braking force applied to the rear wheels of the wheels, and when the braking force is applied to the front wheels, the front part of the vehicle is moved upward. When an anti-dive force, which is a force that displaces the rear wheels, is generated and a braking force is applied to the rear wheels, a rear wheel anti-lift force, which is a force that displaces the rear part of the vehicle downward, is generated on the front wheels. When the braking force applied to the rear wheels and the braking force applied to the rear wheels are of the same magnitude, the first force, which is one of the anti-dive force and the rear wheel anti-lift force, is the other. It is applied to vehicles that are configured to be greater than the second force, which is the force.
A braking control unit that controls the braking device is provided.
The braking control unit uses the wheel that generates the second force to the vehicle by applying the braking force when the vehicle is stopped as the main braking wheel, and the main braking of the braking force applied to the vehicle. A vehicle control device that operates the braking device so as to increase the proportion of the braking force applied to the wheels. The braking control unit operates the braking device so that the braking force applied to the vehicle is satisfied by the braking force applied to the main braking wheel when the vehicle is stopped. Vehicle control device. The vehicle is provided with a drive device capable of separately adjusting the driving force transmitted to the front wheels and the driving force transmitted to the rear wheels, and when the driving force is transmitted to the front wheels, the front portion of the vehicle is displaced downward. When the front wheel anti-lift force, which is a force, is generated and the driving force is transmitted to the rear wheels of the vehicle, the anti-squart force, which is a force that displaces the rear part of the vehicle upward, is generated and transmitted to the front wheels. When the driving force applied and the driving force transmitted to the rear wheels are of the same magnitude, the third force, which is one of the front wheel anti-lift force and the anti-squat force, is the other force. It is a vehicle that is configured to be larger than a certain fourth force,
When the vehicle is started from a stopped state, the wheels that generate the third force in the vehicle by transmitting the driving force are used as the main driving wheels, and the driving force of the vehicle is transmitted to the main driving wheels. The vehicle control device according to claim 1 or 2, further comprising a drive control unit that operates the drive device so as to increase the proportion of force. The third aspect of the present invention, wherein the drive control unit operates the drive device so that the drive force of the vehicle is satisfied by the drive force transmitted to the main drive wheels when the vehicle is started from a stopped state. Vehicle control device. It is a vehicle having a braking device capable of separately adjusting the braking force applied to the front wheels of the wheels and the braking force applied to the rear wheels of the wheels, and when the braking force is applied to the front wheels, the front part of the vehicle is moved upward. When an anti-dive force, which is a force that displaces the rear wheels, is generated and a braking force is applied to the rear wheels, a rear wheel anti-lift force, which is a force that displaces the rear part of the vehicle downward, is generated on the front wheels. When the braking force applied to the rear wheels and the braking force applied to the rear wheels are of the same magnitude, the first force, which is one of the anti-dive force and the rear wheel anti-lift force, is the other. It is applied to vehicles that are configured to be greater than the second force, which is the force.
It causes the computer to execute the function of controlling the braking device.
In the function of controlling the braking device, among the braking forces applied to the vehicle, the wheels that generate the second force in the vehicle by applying the braking force when the vehicle is stopped are used as the main braking wheels. A vehicle control program that operates the braking device so as to increase the proportion of the braking force applied to the main braking wheel.

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