JP2010221850A - Attitude control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a force applied to a steering system by changing an attitude of a vehicle to increase a load of a steering wheel, and making it difficult to steer the steering wheel. <P>SOLUTION: In S100, a velocity V of a vehicle is referred to. Next, in S110, it is determined whether the velocity V of the vehicle is larger than V<SB>0</SB>or not. If yes, the step goes to S130, so as to refer to a distance d between a vehicle 4 and an edge stone. Thereafter, in S140, it is determined whether the distance d is smaller than d<SB>0</SB>or not. If yes, the step goes to S150, it is determined that an automatic brake is turned on and a damping force is small. The automatic brake is turned on, and the damping force of each damping force variable part 22 provided near each wheel 12 is changed to be small. Thereby, wheels 12FR, 12FL which are steering wheels are steered, so as to reduce a force applied to the steering system and constitute the steering system at low cost. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an apparatus for controlling the attitude of a vehicle, and more particularly to an apparatus for changing the load of a steered wheel by controlling the attitude of the vehicle.

While traveling, the vehicle receives various forces from the road surface. When the force exerted on the vehicle is relatively small, the suspension device of each wheel absorbs this, and the force exerted on the vehicle is minimized. However, when traveling near an obstacle that may exert a large force on the vehicle, such as a gutter or a curbstone, it is desirable to avoid a situation in which a large force is exerted on the vehicle without contacting the obstacle. Even when the vehicle is in contact with an obstacle, it is desirable to minimize the force exerted on the vehicle.

Patent Document 1 determines whether or not a vehicle is in contact with an obstacle, and when it is determined that the vehicle is in contact with an obstacle, the vehicle generates a braking force so that the vehicle is in contact with the obstacle. It is to prevent. Japanese Patent Laid-Open No. 2004-228867 prevents a large force from being applied to the steering system by disconnecting a clutch of a motor that assists the steering wheel when the steering wheel of the vehicle rides on the curb.

JP 2004-90869 A JP-A-6-8839

About the said patent document 1, since it prevents that a vehicle contacts an obstruction, the countermeasure when a vehicle contacts a curbstone etc. was inadequate. Further, Patent Document 2 has a problem that the force exerted on the steering system cannot be sufficiently reduced because the clutch of the motor is disengaged after the vehicle rides on the curb.

By the way, in recent years, many vehicles equipped with an electric power steering device have been put into practical use. Even in such vehicles, a relatively large external force may be exerted on the tire due to the tire (wheel) hitting the curb. is there. In such a case, the tire is steered (turned) in response to the force from the curb, and accordingly, the rack shaft moves to the stroke end. At this time, the steering shaft that has been rotated by the movement of the rack shaft stops rotating when the movement of the rack shaft stops, but the rotor (rotor) of the motor part of the electric power steering device that has been rotated together with the steering shaft and the steering are stopped. The wheel tries to keep turning due to inertia. For this reason, it is necessary to secure the strength of the steering system, such as increasing the strength of the steering shaft and the gear portion, in order to receive the rotational torque from the rotor and the steering wheel, which causes an increase in cost.

Therefore, the present invention has been made to solve the above-described problems. By controlling the posture of the vehicle, the load on the steering wheel is increased to make it difficult for the steering wheel to be steered. The purpose is to reduce the force generated.

The present invention has been devised to achieve the above object, and includes a vehicle speed detection unit that detects the speed of the vehicle, a distance detection unit that detects a distance between the vehicle and the curb, Based on the distance, a contact determination unit that determines whether or not a vehicle wheel contacts the curb, and when the contact determination unit determines that the wheel contacts the curb, the vehicle generates a braking force. A braking force generating unit; and a damping force changing unit that reduces the magnitude of the damping force of the shock absorber of at least one wheel of the vehicle when the contact determining unit determines that the wheel contacts the curb. It is comprised by the attitude control apparatus of the vehicle characterized by the above.

According to this configuration, it is determined whether or not the vehicle wheel contacts the curb based on the vehicle speed and the distance from the curb. When it is determined that the wheel contacts the curb, braking force is generated in the vehicle. The damping force of the shock absorber of at least one wheel is reduced, and the attitude control of the vehicle is performed. At this time, the vehicle is in a nose dive state, and the load on the steered wheel is increased by the amount that the load on the non-steered wheel is reduced. Therefore, even when the curb is in contact with the wheel that is the steered wheel, the load on the steered wheel is increased, so that sufficient frictional force is generated between the road surface and the wheel, so that the wheel that is the steered wheel is curb. It becomes difficult to be steered by the power from.

According to another aspect of the present invention, a vehicle speed detection unit that detects a vehicle speed, a distance detection unit that detects a distance between the vehicle and the curb, and a vehicle speed and distance detected based on the detected vehicle speed and distance. A contact determination unit that determines whether or not a wheel contacts the curb, and a vehicle height on the front wheel side of the vehicle is changed to be low when the vehicle is determined to contact the curb by the contact determination unit. And a vehicle height control unit that changes the vehicle height on the rear wheel side of the vehicle so as to increase.

According to this configuration, based on the vehicle speed and the distance from the curb, whether or not the vehicle wheel contacts the curb is determined, and if it is determined that the wheel contacts the curb, the vehicle height on the front wheel side of the vehicle Is lowered, and the vehicle height on the rear wheel side is raised to control the attitude of the vehicle. At this time, the vehicle is in a nose dive state, and the load on the steered wheel is increased by the amount that the load on the non-steered wheel is reduced. Therefore, even when the curb is in contact with the wheel that is the steered wheel, the load on the steered wheel is increased, so that a sufficient frictional force is generated between the road surface and the wheel, so that the wheel that is the steered wheel is curb. It becomes difficult to be steered by the power from.

According to said structure, the wheel which is a steering wheel becomes difficult to be steered with the force from a curb, the rotational speed of the site | part rotated with the force from a curb is suppressed, and the force exerted on a steering system is reduced. Therefore, it is possible to configure the steering system at a low cost.

It is the schematic which shows the whole structure of the attitude | position control apparatus 2 of the 1st Embodiment of this invention. It is the schematic which shows the relationship between each control part and each sensor of the 1st Embodiment of this invention. It is a schematic block diagram of the steering device 30 applied to the 1st Embodiment of this invention. It is a flowchart for demonstrating the attitude | position control of the 1st Embodiment of this invention. It is a schematic diagram for demonstrating the calculation method of the distance d used in the 1st Embodiment of this invention. It is the schematic which shows the whole structure of the attitude | position control apparatus 48 of the 2nd Embodiment of this invention. It is the schematic which shows the relationship between each control part and each sensor of the 2nd Embodiment of this invention. It is a flowchart for demonstrating the attitude | position control of the 2nd Embodiment of this invention.

Embodiments for carrying out the present invention will be described in detail below. FIG. 1 is a schematic diagram showing the overall configuration of a vehicle attitude control device 2 according to a first embodiment of the present invention. In FIG. 1, the attitude control device 2 includes an attitude control unit 6, a brake control unit 8, and a damping force control unit 10 that are mounted on a vehicle 4. The attitude control unit 6 controls the attitude of the vehicle 4, and the load applied to the right rear wheel 12RR and the left rear wheel 12RL, which are non-steering wheels, by setting the attitude of the vehicle 4 to a so-called nose dive state. And the load applied to the right front wheel 12FR and the left front wheel FL is increased. Two clearance sonars 14 arranged at the foremost part of the vehicle are connected to the attitude control unit 6. The clearance sonar 14 is disposed at the foremost portion of the vehicle and at the vehicle width direction end portion of the vehicle, and the clearance sonar 14 disposed at the right end portion of the vehicle is disposed at the clearance sonar 14R and the left end portion of the vehicle. Is a clearance sonar 14L. The clearance sonar 14 is capable of detecting a relatively low object such as a curbstone and measuring the distance to the object.

The brake control unit 8 mounted on the vehicle 4 controls the pressure of the wheel cylinder of each wheel 12 and performs control for operating the brake actuator 16. The brake control unit 8 is connected to wheel speed sensors 18FR, 18FL, 18RR, 18RL provided to the wheels 12FR, 12FL, 12RR, 12RL, respectively, and detects the value of the wheel speed sensor 18 of each wheel 12. Thus, it is possible to calculate the speed of the vehicle, to obtain the slip ratio calculated from the speed of the vehicle and the speed of each wheel. The brake control unit 8 is connected to the attitude control unit 6 through a signal line, and transmits information (vehicle speed, etc.) of the brake control unit 8 to the attitude control unit 6 or a command (automatic operation) of the attitude control unit 6. Brake control or the like) can be transmitted to the brake control unit 8.

The brake actuator 16 connected to the brake control unit 8 is connected to the brake cylinders 20FR, 20FL, 20RR, and 20RL of each wheel 12 by brake piping, and operates a built-in pump and solenoid valve. Thus, the hydraulic pressure of the wheel cylinder of each wheel 12 is increased (increased) or decreased (depressurized) to change the magnitude of the brake force of each brake operating unit 20. Each brake operating unit 20 is independently connected to the brake actuator 16, and the brake control unit 8 operates the brake actuator 16, so that the magnitude of the brake force of each brake operating unit 20 is independently set. It is possible to control.

The damping force control unit 10 mounted on the vehicle is connected to the damping force variable units 22FR, 22FL, 22RR, and 22RL of the shock absorber of each wheel 12 and controls the damping force of each damping force varying unit 22. Is. Note that the configuration of the damping force variable unit 22 is a well-known one. For example, the magnitude of the damping force is changed by changing the area of the flow path through which the liquid flows by switching the rotary valve in the shock absorber. Can be adopted. Each damping force variable unit 22 is independently connected to the damping force control unit 10, and the damping force control unit 10 can independently control the magnitude of the damping force of each damping force variable unit 22. It is possible. Note that the magnitude of the damping force of each damping force variable unit 22 may be such that when the damping force changes from a small state to a large state, the damping force may increase linearly, or the damping force increases stepwise. It's also good. Further, the damping force control unit 10 is connected to the attitude control unit 6 through a signal line, and can transmit a command (damping force: small control, etc.) of the attitude control unit 6 to the damping force control unit 22. ing.

Next, the relationship between each control unit and each sensor of the attitude control device 2 of the present embodiment will be described with reference to FIG. FIG. 2 is a schematic diagram illustrating the relationship between each control unit and each sensor of the attitude control device 2. In FIG. 2, the posture control unit 6 includes a curb contact determination unit 24, an automatic brake operation instruction unit 26, and a damping force change instruction unit 28. The curb contact determination unit 24 is a part that determines whether or not each wheel 12 of the vehicle, in particular, the front wheels 12FR and 12FL may come into contact with the curb, and the signals of the clearance sonars 14R and 14L are input. ing. The curb contact determination unit 24 uses the vehicle speed V when making contact determination, and the vehicle speed V is transmitted from the brake control unit 8.

After the curb contact determination unit 24 determines the possibility of contact with the curb, the automatic brake operation instruction unit 26 transmits a control instruction signal to the brake control unit 8 based on the transmission signal from the curb contact determination unit 24. To do. The brake control unit 8 transmits a signal for controlling the brake actuator 16 to the brake actuator 16 based on the control instruction signal from the automatic brake operation instruction unit 26, and the brake actuator 16 transmits the brake cylinder 16 of each brake operation unit 20. Adjust fluid pressure.

In addition, after the curb contact determination unit 24 determines the possibility of contact with the curb, the damping force change instruction unit 28 instructs the damping force control unit 10 to control based on the transmission signal from the curb contact determination unit 24. Send a signal. The damping force control unit 10 transmits a signal for controlling each damping force variable unit 22 to each damping force variable unit 22 based on the control instruction signal from the damping force change instruction unit 28, and each damping force variable unit 22. Adjusts the magnitude of the damping force of the shock absorber of each wheel 12.

Next, a structure of a rack and pinion type steering device applied to the vehicle 4 on which the attitude control device 2 according to the first embodiment of the present invention is mounted will be described with reference to FIG. FIG. 3 is a schematic diagram illustrating the overall configuration of the steering device 30.

The steering device 30 includes a steering wheel 32, a steering shaft 34 that rotates as the steering wheel 32 rotates, an intermediate shaft 36 that is connected to the steering shaft 34 via a universal joint, an intermediate shaft 36, and a universal joint. The pinion shaft 38 is connected to the pinion shaft 38, and the steering gear portion 40 is engaged with the pinion shaft 38 in gear.

The steering gear unit 40 includes a rack housing 42 held on the vehicle side via a bush, a rack shaft housed in the rack housing 42 and movable in the axial direction (vehicle width direction), and a pinion shaft. The pinion gear is formed integrally with the lower end portion of 38 and meshes with the rack gear formed on the rack shaft. Further, tie rods 44 are connected to both ends of the rack shaft (ends in the vehicle width direction) via ball joints, and the tie rods 44 are connected to the vehicle tire 12 via a knuckle arm and a knuckle (not shown). Has been. The rack shaft can move to the stroke end which is the maximum amount that the rack shaft can move in the axial direction, and the rack shaft moves to the stroke end and is stopped.

An electric power steering mechanism 46 is disposed in the vicinity of the steering shaft 34. The electric power steering mechanism 46 includes a stator fixed to the inner wall of the housing and a rotor (rotor) disposed inside the stator, and the rotation of the rotor is output from the motor unit by the motor shaft. Rotate. The worm gear meshes with a wheel gear that rotates together with the steering shaft 34, and the rotation of the motor unit is transmitted to the steering shaft 34 as an assist force. That is, the worm gear and the wheel gear constitute a reduction gear.

Next, the control performed by the attitude control unit 6 will be described with reference to FIG. FIG. 4 is a flowchart for explaining a posture control method in consideration of contact with the curbstone. The posture control method in FIG. 4 is executed at predetermined intervals (for example, 5 msec). In step 100 of FIG. 4 (hereinafter abbreviated as S100. The same applies to the following steps), the vehicle speed V is referred to. As described above, the vehicle speed V calculated by the brake control unit 8 is used as the vehicle speed V. In the brake control unit 8, the vehicle speed V can be obtained from the value of each wheel speed sensor 18. For example, each wheel speed sensor is in operation during braking (when the brake stop lamp switch is ON). The value of the wheel speed sensor with the highest speed among 18 is the vehicle speed V, and the wheel speed with the lowest speed among the wheel speed sensors 18 when the brake is not operated (when the brake stop lamp switch is OFF). The value of the sensor is the vehicle speed V.

Then, the process proceeds to S110, whether or not the speed V of the vehicle is greater than the speed V ₀ set in advance is determined. The value of V _{0 is} a value set in association with a distance d ₀ to be described later. For example, V ₀ = 10 km / h is set. If the vehicle speed V is lower than V ₀ , that is, if the vehicle speed V is relatively low, it can be determined that the possibility that the wheel 12 of the vehicle 4 will contact the curb is low, and thus the process proceeds to S120. The instruction content of the automatic brake operation instruction unit 26 is determined to be automatic brake: OFF, and the instruction content of the damping force change instruction unit 28 is determined to be damping force: standard. Based on this, the automatic brake operation instructing unit 26 instructs the brake control unit 8 to turn off the automatic brake. If the brake control unit 8 does not operate the automatic brake, the automatic brake operation instructing unit 26 indicates that the automatic brake is not operated. continue. On the other hand, when the brake control unit 8 is operating the automatic brake by the control of S150 described later, the brake actuator 16 is controlled by the automatic brake: OFF instruction of S120, and the operation of the automatic brake is terminated.

In S120, the damping force change instruction unit 28 instructs the damping force control unit 10 to set the damping force of each damping force variable unit 20 to a standard state. When the damping force control unit 10 does not reduce the damping force by S150 described later, the damping force control unit 10 does not change the magnitude of the damping force. On the other hand, when the damping force control unit 10 reduces the damping force of each damping force variable unit 22 by S150 described later, the reduced damping force is returned to the original state. In other words, to set the damping force of each damping force variable unit 22 to the standard state, the magnitude of the damping force of each damping force variable unit 22 is changed to the magnitude of the damping force from which the influence of the change of the S150 damping force is removed. The magnitude of the damping force of each damping force variable unit 22 when the damping force is restored is based on the state quantity of the vehicle (the amount of change in the speed of the vehicle, the amount of change in the steering speed), etc. It is determined by the control unit 10. Thereafter, the posture control is temporarily terminated.

On the other hand, in S110, when the speed V of the vehicle is greater than V _0, i.e., when the velocity V of the vehicle is relatively high, it is determined that the wheel 12 of the vehicle 4 is more likely to contact the curb, Proceed to S130. In S130, the distance d between the vehicle and the curb is referred to. Here, with reference to FIG. 5, a method of calculating the distance d between the vehicle 4 and the curb will be described. FIG. 5 is a schematic diagram for explaining a method of calculating the distance d between the vehicle 4 and the curb.

In FIG. 5, when the vehicle 4 is traveling in the vicinity of the curb 30, clearance sonars 14 </ b> R and 14 </ b> L respectively disposed at both front ends of the vehicle 4 measure the distance between the curb 30 and the clearance sonar 14 </ b> R. There as the distance to be measured is d _R, the distance clearance sonar 14L is measured as d _L, are respectively input to the attitude control unit 6. The distance d between the vehicle 4 and the curb 30 is calculated from the value of d _R and d _L, in the present embodiment, by comparing the d _R and d _L, the shorter distance between the distance d. Therefore, in the state shown in FIG. 5, the distance d _R measured by the clearance sonar 14 </ b> R is the distance d between the vehicle 4 and the curb 30. The method of calculating the distance d between the vehicle 4 and the curb 30 is not limited to the above-described method. For example, the average value of d _R and d _L may be used as the distance d between the vehicle 4 and the curb 30. good. In addition, when the distance to the curb 30 measured by the clearance sonars 14R and 14L is very large, that is, when the curb 30 is not present in front of the vehicle 4, the distance d between the vehicle 4 and the curb 30 is predetermined. Value d _M (d _M is a sufficiently large value such as 50 m).

As described above, the distance d between the vehicle 4 and the curb 30 is calculated, and the distance d is referred to in S130. Thereafter, the process proceeds to S140, whether or not the distance d between the vehicle 4 and the curb is less than d ₀ is determined. The value of d ₀ is set in association with the aforementioned vehicle speed V _0, and for example, d ₀ = 0.5 m is set. If the distance d is greater than _{d 0,} the decision in S140 is negative, the process proceeds to S120, automatic brake: OFF, the damping force magnitude: the standard and determined. This is because it is determined that the possibility that the wheel 12 of the vehicle 4 contacts the curb is low.

On the other hand, when the distance d is less than d _0, the decision in S140 is affirmative, the process proceeds to S150, instruction content automatic brake of the automatic brake operation instruction unit 26: determines the ON, an instruction of the damping force change instruction section 28 The content is determined to be damping force: small. Based on this, the automatic brake operation instructing unit 26 issues an instruction to turn on the automatic brake to the brake control unit 8, and the brake control unit 8 operates the brake actuator 16 and causes each brake operation unit 20 to generate a braking force. The damping force change instruction unit 28 instructs the damping force control unit 10 to reduce the damping force, and the damping force control unit 10 operates each damping force variable unit 22 so that the shock absorber of each wheel 12 is operated. The damping force is reduced. Thereafter, the posture control is temporarily terminated.

Under the control of S150, the posture of the vehicle 4 changes as follows. When the automatic brake is activated, the vehicle 4 tries to keep moving forward due to inertial force. At this time, the vehicle 4 rotates around an axis (pitching axis) extending in the vehicle width direction. Since the position of the center of gravity of the vehicle 4 is vertically above the position of the pitching shaft, the vehicle 4 is in a nose dive state in which the front wheel side is lowered vertically and the rear wheel side is raised vertically. In this state, the load applied to the wheel 12 on the rear wheel side of the vehicle 4 decreases, and the load applied to the wheel 12 on the front wheel side of the vehicle 4 increases. Therefore, by operating the automatic brake on the vehicle 4, the posture of the vehicle 4 can be changed to a nose dive state, thereby increasing the loads on the wheels 12FR and 12FL that are the steering wheels.

Further, when the magnitude of the damping force of each damping force variable unit 22 is changed and the damping force of the shock absorber of each wheel 12 is reduced, the vehicle 4 is compared with the case where the damping force of the shock absorber is large. It will be in the state which is easy to carry out the relative displacement to the up-down direction (vertical direction) with respect to the wheel 12. FIG. In such a state, when the vehicle 4 is operated with the automatic brake, the vehicle 4 is in a nose dive state as described above. However, when the damping force of the shock absorber is small, the vehicle 4 is larger than when it is large. The degree of nose dive becomes large. That is, when the damping force of the shock absorbers of the front wheel wheels 12FR and 12FL is reduced, the front wheel side of the vehicle 4 is displaced further downward in the vertical direction as compared with the case where the shock absorber is large. When the damping force of the 12RR and 12RL shock absorbers is reduced, the rear wheel side of the vehicle is displaced further upward in the vertical direction as compared with the case where the damping force is large. Therefore, by reducing the magnitude of the damping force of each damping force variable portion 22, the degree of nose dive of the vehicle 4 generated by the automatic braking can be further increased, so that the front wheel side which is the steering wheel can be increased. It becomes possible to further increase the loads on the wheels 12FR and 12FL.

Therefore, in the first embodiment of the present invention, since the loads on the front wheels 12FR and 12FL, which are the steering wheels, are increased, the wheels 12FR, 12FL which are the steering wheels of the vehicle 4 come into contact with the curb, and the curb It is possible to reduce the speed (steering speed) when the wheels 12FR and 12FL are steered in the steering direction by receiving more force. If the loads on the front wheels 12FR and 12FL are increased, the frictional force between the wheel 12 and the road surface increases, so the frictional force becomes a force that resists the force from the curb, and the speed at which the wheel 12 is steered. Can be suppressed. Therefore, by suppressing the turning speed of the wheels 12, the moving speed of the rack shaft in the rack housing 42 is also suppressed, and the speed when the rack shaft comes into contact with the stroke end is also reduced. As a result, the rotational torque received by the steering shaft 34 from the rotor (rotor) of the electric power steering mechanism 46 and the steering wheel 32 becomes small, and the steering device 30 can be configured at low cost.

In the above-described first embodiment of the present invention, in S150, the automatic brake is set to ON and the damping force is set to small. However, by operating the automatic brake on the vehicle 4, the vehicle 4 is in a nose dive state. In S150, it is not essential to reduce the magnitude of the damping force. On the other hand, since the vehicle 4 cannot be brought into a nose dive state only by reducing the damping force of the shock absorber of the wheel 12 of the vehicle 4, in S150, the determination of the damping force: small is automatic braking: ON Used in combination with the determination. In S150, the timing at which the damping force of the damping force varying unit 22 is reduced may be before, at the same time as, or after the timing at which the vehicle 4 is operated by the automatic brake. In order to increase the degree of the dive, it is desirable that the timing at which the damping force of the damping force varying unit 22 is reduced is before or at the same time as the timing at which the vehicle 4 is operated by the automatic brake. In S150, reducing the damping force of the damping force variable unit 22 includes reducing the magnitude of the damping force with respect to the magnitude of the damping force of the damping force variable unit 22 before the control of S150. However, in order to increase the degree of nose dive of the vehicle 4, it is desirable to change the magnitude of the damping force of the damping force variable unit 22 to the smallest.

Next, a second embodiment of the present invention will be described. Unlike the first embodiment, the second embodiment controls the attitude of the vehicle using a vehicle height control mechanism for each wheel. FIG. 6 is a schematic diagram showing the overall configuration of the vehicle attitude control device 48 according to the second embodiment of the present invention. In addition, about 2nd Embodiment, the same number is attached | subjected about the part of the same structure as 1st Embodiment, description is abbreviate | omitted, and a different structure is demonstrated below.

In FIG. 6, the attitude control device 48 includes an attitude control unit 50, a brake control unit 8, and a vehicle height control unit 52 that are mounted on the vehicle. The vehicle height control unit 52 is connected to vehicle height adjustment units 54FR, 54FL, 54RR, 54RL provided between the wheels 12 and the vehicle body, and controls the adjustment amount of each vehicle height adjustment unit 54. . Note that the configuration of the vehicle height adjusting unit 54 is a known one. For example, the vehicle height adjusting unit 54 is configured to change the volume of the air chamber and change the vehicle height by controlling the inflow and outflow of air in the air chamber. Can be adopted. Each vehicle height adjustment unit 54 is independently connected to the vehicle height control unit 52, and the vehicle height control unit 52 can independently control the adjustment amount of each vehicle height adjustment unit 54. ing. In addition, when the adjustment amount changes from a small state to a large state, the adjustment amount of each vehicle height adjustment unit 54 may be increased linearly, or the adjustment amount increases stepwise. It's also good. Further, the vehicle height control unit 52 is connected to the posture control unit 50 through a signal line, and can transmit a command (such as adjustment amount increase control) of the posture control unit 50 to the vehicle height control unit 52. Yes.

Next, the relationship between each control unit and each sensor of the attitude control device 48 of the second embodiment will be described with reference to FIG. FIG. 7 is a schematic diagram showing the relationship between each control unit and each sensor of the attitude control device 48. In FIG. 7, the posture control unit 50 includes a curb contact determination unit 56 and a vehicle height change instruction unit 58. After the curb contact determination unit 56 determines the possibility of contact with the curb, the vehicle height change instruction unit 58 transmits a control signal to the vehicle height control unit 52 based on the transmission signal from the curb contact determination unit 56. To do. The vehicle height control unit 52 transmits a signal for controlling each vehicle height adjustment unit 54 to each vehicle height adjustment unit 54 based on the control instruction signal from the vehicle height change instruction unit 58, and each vehicle height adjustment unit 54. Adjusts the amount of vehicle height adjustment for each wheel 12.

Next, the control performed by the attitude control unit 50 will be described with reference to FIG. FIG. 5 is a flowchart for explaining a posture control method in consideration of contact with the curb. In S200 of FIG. 8, the vehicle speed V is referred to. Then, the process proceeds to S210, whether or not the speed V of the vehicle is greater than the speed V ₀ set in advance is determined. If the vehicle speed V is smaller than V ₀ , the process proceeds to S120, and the instruction content of the vehicle height change instructing unit 58 is that the front wheel side (Fr) vehicle height: standard, the rear wheel side (Rr) vehicle height: standard. Is determined. Based on this, the vehicle height change instructing unit 58 instructs the vehicle height control unit 52 to set the vehicle height of each vehicle height adjusting unit 54 to a standard state. When the vehicle height control unit 52 does not change the vehicle height of the vehicle 4 in S250 described later, the vehicle height control unit 52 does not change the vehicle height. On the other hand, when the vehicle height control unit 52 changes the vehicle height in S250 described later, the changed vehicle height is returned to the original vehicle height. In other words, when the vehicle height of each vehicle height adjustment unit 54 is set to the standard state, the vehicle height adjustment amount of each vehicle height adjustment unit 54 is the size of the adjustment amount from which the influence of the vehicle height change in S250 is removed. The amount of adjustment of each vehicle height adjustment unit 54 when the vehicle is returned to the original is based on the vehicle state quantity (vehicle speed change amount, steering steering speed change amount, etc.) It is determined by the high control unit 52. Thereafter, the attitude control ends.

On the other hand, if the speed V of the vehicle is greater than V ₀ in S210, the process proceeds to S230 where the distance d between the vehicle and the curb is referred to, and then the process proceeds to S240 where the distance d between the vehicle 4 and the curb is d _0. Or less is determined. If the distance d is greater than _{d 0,} the process proceeds to S220.

On the other hand, when the distance d is less than _{d 0,} the process proceeds to S250, the instruction content of the vehicle height changing instruction unit 58, front wheel vehicle height: down, the rear wheel side of the vehicle height: is up and determined. Based on this, the vehicle height change instruction unit 58 instructs the vehicle height control unit 52 to lower the vehicle height on the front wheel side and raise the vehicle height on the rear wheel side, and the vehicle height control unit 52 Control to lower the vehicle height on the front wheel side by operating the vehicle height adjustment units 54FR and 54FL, and control to increase the vehicle height on the rear wheel side by operating the vehicle height adjustment units 54RR and 54RL on the rear wheel side. Do. Thereafter, the attitude control ends.

The attitude of the vehicle changes as follows by the control of S250. When the vehicle height on the front wheel side is lowered, the vehicle 4 is in a nose dive state, and the loads on the wheels 12FR and 12FL on the front wheel side increase. Similarly, when the vehicle height on the rear wheel side is raised, the vehicle 4 is in a nose dive state, and the loads on the front wheels 12FR and 12FL, which are steered wheels, increase.

Therefore, in the second embodiment of the present invention, since the load on the front wheels 12FR and 12FL, which are the steering wheels, is increased, the wheel 12 of the vehicle 4 contacts the curb and receives the force from the curb and receives the force from the curb. The speed (steering speed) when 12FR and 12FL are steered in the steering direction can be reduced. Therefore, the turning speed of the wheels 12 is suppressed, so that the speed when the rack shaft in the rack housing 42 abuts against the stroke end is also reduced. As a result, from the rotor and the steering wheel 32 of the electric power steering mechanism 46. The rotational torque received by the steering shaft 34 is also small, and the steering device 30 can be configured at low cost.

6 Attitude Control Unit 8 Brake Control Unit 10 Damping Force Control Unit 12 Wheel 14 Clearance Sonar 18 Wheel Speed Sensor 20 Brake Actuation Unit 22 Damping Force Variable Unit 24 Curb Contact Determination Unit

Claims (2)

A vehicle speed detector for detecting the speed of the vehicle;
A distance detector for detecting the distance between the vehicle and the curb;
A contact determination unit that determines whether a vehicle wheel contacts the curb based on the detected vehicle speed and distance;
A braking force generation unit that generates a braking force on the vehicle when the contact determination unit determines that a wheel contacts the curb;
A damping force changing unit that reduces the magnitude of the damping force of a shock absorber of at least one wheel of the vehicle when the contact determination unit determines that a wheel contacts the curb;
A vehicle attitude control apparatus comprising: A vehicle speed detector for detecting the speed of the vehicle;
A distance detector for detecting the distance between the vehicle and the curb;
A contact determination unit that determines whether a vehicle wheel contacts the curb based on the detected vehicle speed and distance;
When the contact determination unit determines that the vehicle contacts the curb, the vehicle height on the front wheel side of the vehicle is changed to be low, and the vehicle height on the rear wheel side of the vehicle is changed to be high. A vehicle height control unit;
A vehicle attitude control apparatus comprising:

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