JPH05213033A - Camber angle control device for vehicle - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a control device for a camber angle in a vehicle suspension, and if there is unevenness on the road surface of the vehicle, the camber angle will not be impaired when riding over the unevenness. The purpose is to be able to control. [Structure] The control means 32 includes a road surface state detection means 39.
When irregularities on the traveling road surface are detected by, the camber angle adjusting mechanism 2 to set the camber angle at which the grounding pin offset of the wheel can be 0 or a value close to 0 in order to reduce the input sensitivity of the irregularities on the road surface to the vehicle. 8 is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camber angle control device for a vehicle suspension, and more particularly to controlling the camber angle so as to detect road surface irregularities in advance and reduce the input sensitivity of the irregularities to the vehicle. And a camber angle control device for a vehicle.

[0002]

2. Description of the Related Art In automobiles, it is known that the traveling characteristics and the like of the vehicle can be changed by adjusting the alignment of the suspension, and a camber angle (hereinafter also simply referred to as a camber) which is one of suspension elements.
Is also proposed to improve the running performance of the vehicle.

[0003]

By the way, such a camber angle affects not only the straight running stability and steering performance of the vehicle but also the suspension sensitivity to the input of road surface disturbance. In other words, generally, if the grounding kingpin offset can be made small, the suspension sensitivity to the input of the road surface disturbance can be reduced, and the grounding kingpin offset can be changed by adjusting the camber angle, so that the suspension sensitivity to the input of the road surface disturbance can be reduced by adjusting the camber angle. Become.

Therefore, when traveling on a rough road, the sensitivity of the suspension to the disturbance input may be lowered to improve the riding comfort. Therefore, it is conceivable to control the kingpin offset to ground by adjusting the camber angle to reduce the road surface disturbance input sensitivity when driving on a rough road.
In this case, the determination as to whether the road is a bad road can be made by detecting the input state of the disturbance to the vehicle.

It is also conceivable to detect the input state of the disturbance to the vehicle and feedback control the camber angle so that the disturbance input becomes small. However, the control as described above is effective when the entire traveling road is a bad road, but is effective against the irregularities of the road surface that are present on a normal road such as a road surface seam. Can't handle. In other words, if the unevenness of the road surface is detected from the input state of the disturbance to the vehicle, the vehicle will already get over the unevenness of the road surface at the time of detection, and control will not be in time.

The present invention has been devised in view of the above problems, and if there is unevenness on the road surface of the vehicle, the camber angle can be controlled so as not to impair the riding comfort of the vehicle when riding over the unevenness. An object of the present invention is to provide a vehicle camber angle control device.

[0007]

Therefore, a vehicle camber angle control device of the present invention is a camber angle adjusting mechanism capable of adjusting a camber angle by driving components of a suspension of a wheel in a vehicle, and the above vehicle. The control means for controlling the camber angle adjusting mechanism according to the traveling state of the vehicle, and the road surface state detecting means for detecting the unevenness of the traveling road surface in front of the vehicle. When unevenness of the traveling road surface is detected by the above, the camber angle adjusting mechanism is set to a camber angle that can set the grounding kingpin offset of the wheel to 0 or a value close to 0 in order to reduce the input sensitivity of the unevenness of the road surface to the vehicle. It is characterized in that it is configured to control.

[0008]

In the above-described vehicle camber angle control device of the present invention, when the road surface condition detecting means detects the unevenness of the traveling road surface in front of the vehicle, the control means detects the input sensitivity of the road surface unevenness to the vehicle. The camber angle adjusting mechanism is controlled so that the grounding pin offset of the wheel can be reduced to 0 or a camber angle that can be close to 0. Therefore, when the vehicle gets over the unevenness of the road surface, the grounding kingpin offset of the wheel becomes 0 or a value close to 0, and the input sensitivity of the unevenness of the road surface to the vehicle decreases.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle camber angle control device as an embodiment of the present invention will be described below with reference to the drawings.
Is a block diagram showing the configuration of the main part thereof, FIG. 2 is a configuration diagram schematically showing the whole thereof, FIG. 3 is a front view showing a suspension equipped with the present apparatus, FIG. 4 is a flow chart for explaining its operation, and FIG. 8 is a map relating to the setting of a control amount (correction amount) in the control of this device, FIG. 9 is a schematic front view of a wheel portion for explaining its control principle, and FIG. 10 is a schematic of a wheel portion for explaining its control principle. FIG. 11 is a graph for explaining the control principle.

This camber angle control device for a vehicle is constructed as shown in FIG. In FIG. 2, reference numeral 2 is an actuator for adjusting the camber angle of the left front wheel, 4 is an actuator for adjusting the camber angle of the right front wheel, 6 is an actuator for adjusting the camber angle of the left rear wheel, and 8 is a camber angle of the right rear wheel. Is an actuator for adjusting. These actuators 2 to 8 are composed of hydraulic cylinders, and are specifically provided on the suspension as shown in FIG. 3, for example.

That is, FIG. 3 is a front view of an automobile. An actuator A (= 2 to 8) is interposed between the upper end of a strut S of a strut-type suspension and a vehicle body F, and the actuator A is extended. Alternatively, the upper end position of the strut S is displaced in the vehicle width direction by contracting, whereby each camber θ of each wheel W can be adjusted.

Referring back to FIG. 2 again, each actuator 2, 4, 6 and 8 is an electromagnetic control valve 10, 1 respectively.
It is designed to be driven by 2, 14, and 16.
The control valves 10, 12, 14 and 16 are connected to the pump 20 via the supply passage 18 and to the oil reservoir 24 via the discharge passage 22. The pump 20 is driven by an engine (not shown) or the like and sucks the oil in the oil reservoir 24 and discharges it to the supply path 18. An accumulator 26 is connected to the supply passage 18, and a reservoir 24 is connected to the supply passage 18 via a relief valve 28, so that the supply passage 18 is maintained at a set pressure.

Each of the control valves 10, 12, 14 and 16 is controlled by a control signal from the drive circuit 30 so that each of the actuators 2 to 8 can be locked by prohibiting the oil supply and discharge to and from the actuators 2 to 8. ~ 8 individually takes a second position for supplying and discharging oil in the direction of expansion (positive camber direction) and a third position for supplying and discharging oil in the direction of contraction of each actuator 2-8 (negative camber direction). You can do it.

Therefore, in order to drive the current camber angle to the target camber angle, the control valves 10, 12, 14 and 16 in the first position are switched to the second position or the third position and the actuators 2 to 2 are driven. 8 is expanded / contracted so that when the target camber angle is reached, the drive circuit 3 is returned to the first position.
Control signals are sent from 0 respectively. If the control signal for changing the camber angle is not sent from the drive circuit 30, the control valves 10, 12, 14 and 16 are held in the first position.

Reference numeral 32 denotes a controller as a control means for outputting a control signal to the drive circuit 30. The controller 32 performs a predetermined program processing based on a signal input from each sensor which will be described later, and then to the drive circuit 30. The controller 32 outputs a control signal.
Has a camber angle setting unit (not shown) that sets the camber angle of each wheel, and a camber angle control unit (not shown) that controls the actuator.

Therefore, in the controller 32, the ROM 34 storing the above-mentioned predetermined program and maps used for the program processing (see FIGS. 4 to 8), and an input for inputting an output signal from each sensor (not shown) A circuit, a CPU for executing calculation and processing according to a program, a RAM, an output circuit, and an interface between these respective elements are provided.

When the above-mentioned respective sensors are specifically raised, a stroke sensor 36 as a stroke detecting means for detecting a stroke of a suspension of a vehicle and a steering as a steering detecting means for detecting a steering angle θ _H of a steering wheel (not shown). The sensor 38, a preview sensor (road surface sensor) 39 as a road surface state detecting means, a vehicle speed sensor 40 for detecting a vehicle speed, a displacement sensor 42 for detecting a stroke position of the actuator 2 for the left front wheel, and a actuator 4 for the right front wheel. A displacement sensor 44 for detecting the stroke position, a displacement sensor 46 for detecting the stroke position of the actuator 6 for the left rear wheel, a displacement sensor 48 for detecting the stroke position of the actuator 8 for the right rear wheel, and a load for each wheel. There is a load sensor (not shown) for measurement and a lateral acceleration sensor 50. It As the preview sensor 39, for example, it is conceivable to apply an ultrasonic sensor which is arranged in front of the vehicle body and inclined downward, and the preview sensor 39 is provided for each of the left and right wheels.

The controller 32 is provided with a portion for controlling the camber angle for reducing the input sensitivity of the unevenness of the road surface to the vehicle. Such a part
For example, it is configured as shown in the block diagram of FIG.
That is, as shown in FIG. 1, the controller 32 sets a camber angle control amount that sets the camber angle control amount so as to set the grounding kingpin offset of the wheel to 0 based on the road surface unevenness detection signal from the preview sensor 39. The detection signal from the lateral acceleration sensor 50 and the steering angle corresponding correction amount setting unit 32B that sets the correction amount Dθ _H corresponding to the steering angle θ _H based on the detection signal from the steering angle sensor 38. A lateral acceleration corresponding correction amount setting unit 32C for setting a correction amount corresponding to the lateral acceleration (lateral G) applied to the vehicle based on the above.

When the signal from the preview sensor 39 is received, the camber angle control amount setting section 32A sets and outputs the control amount L so that the camber angle is set so that the ground kingpin offset becomes zero. ing. The reason why the control amount L is set so that the grounding kingpin offset is 0 is to reduce the sensitivity of the wheel (that is, the vehicle) to the disturbance from the road surface. Regarding this principle, refer to FIGS. explain.

FIG. 9 is a schematic front view of a wheel showing a grounding kingpin offset of the wheel. In both (A) and (B), the right side in the figure is the outside of the vehicle body, and (A) has a camber angle of 0. Or it shows the case of the initial state close to 0,
(B) shows a case where the camber angle is controlled. Further, FIG. 10 is a schematic plan view of the wheel showing the grounding kingpin offset of the wheel together with the front and rear inputs to the wheel.

As shown in FIG. 9 (A), generally, the kingpin axis is set to incline toward the outside of the vehicle body with respect to the road surface. Then, normally, there is a distance between the center B of the tire application point and the point A on the road surface of the kingpin axis, that is, the ground kingpin offset d as shown in the figure. By the way, the reaction force that wheels receive from the road surface (disturbance)
Acts on the center B of the tire force, and, for example, a road surface reaction force (road surface disturbance) in the front-rear direction acts as shown by an arrow F in FIG. It is considered that such a road surface disturbance acts on the wheel side (and therefore the vehicle side) as a moment M about the kingpin axis. This moment M is expressed as M = d × F from the road surface disturbance F and the ground kingpin offset d. The smaller the ground kingpin offset d is, the smaller the moment M is, and the influence of the road surface disturbance on the wheel side (and therefore the vehicle side). Can be reduced.

This can be seen from the graph shown in FIG. In this graph, the correlation characteristic of the lateral acceleration of the wheel with respect to the ground kingpin offset d when the wheel is subjected to disturbance is obtained by an experiment, and it is understood that the smaller the ground kingpin offset d is, the smaller the lateral acceleration applied to the wheel is. .. Then, the grounding kingpin offset d can be changed by adjusting the camber angle. Therefore, in this case (when the point A of the kingpin axis is outside the tire applying point center B), for example, as shown in FIG.
By adjusting the camber angle to the positive side, the grounding kingpin offset d can be changed to 0 or a value close to 0, that is, the influence of road surface disturbance (that is, road surface disturbance sensitivity) can be reduced. In FIG. 9B, the adjustment of the camber angle is exaggerated for the sake of convenience.

By the way, the ground kingpin offset is set to 0.
If the camber angle of the vehicle is in the initial state, the control amount L of the camber angle to be set to is a value determined in advance corresponding to the value θ ₀ of the initial camber angle. Therefore, assuming that the control amount L when the camber angle is in the initial state is the initial control amount L ₀ , the initial control amount L ₀ is L ₀ = −θ ₀ .

When the vehicle is traveling straight ahead, this initial control amount L ₀ may be set as the control amount L.
When the vehicle is in the steering state or is turning, the camber angle changes due to the turning of the wheels and the camber angle changes due to the roll of the vehicle body. Therefore, the initial control amount L ₀ is corrected to obtain the control amount L. Must be set. Therefore, in such a case, the initial control amount L _{0 is set} to the steering angle θ _H
Correction amount D? _H and the roll of the vehicle body corresponding to the (here the lateral acceleration corresponding to the roll) is corrected by adding the correction amount L based on the correction amount D _GY corresponding to _{'(= Dθ H + D GY} ) , Target camber angle control amount L (= L ′ +
L ₀ ) is set.

In the steering angle corresponding correction amount setting section 32B, the control correction amount D is calculated according to the steering angle θ _H from the map as shown in FIG.
Set θ _H. This is because the camber angle θ changes according to the steering angle, that is, the steering angle θ _H when the wheels are steered and steered. 6, the horizontal axis indicates the steering angle θ _H , the right side of the horizontal axis is the steering angle to the right, the left side of the horizontal axis is the steering angle to the left, and the vertical axis is the control correction. The amount Dθ _H is shown, and the upper side of the vertical axis is the correction amount to the positive side, and the lower side of the vertical axis is the correction amount to the negative side. The solid line indicates the correction amount for the right wheel, and the chain line indicates the correction amount for the left wheel.

The change of the camber angle θ with respect to the steering angle θ _H is
There are various patterns depending on the direction of the kingpin axis,
For example, as shown in FIG. 5, the camber angle θ of the wheel on the turning inner wheel side (steering direction side) changes to the positive side, and the camber angle θ of the wheel on the turning outer wheel side (side opposite to the steering direction) changes to the negative side. It may change. The map shown in FIG. 6 is set corresponding to the characteristics of the camber angle change as shown in FIG.

In FIG. 5, the right side of the horizontal axis is the steering angle to the right, the left side of the horizontal axis is the steering angle to the left, the upper side of the vertical axis is the camber angle change amount to the positive side, and the lower side of the vertical axis. The side is the camber angle change amount to the negative side, the solid line shows the characteristic for the right wheel, and the chain line shows the characteristic for the left wheel. As shown in the figure, when steering to the right, for example, the right wheel, which is the inner wheel, changes to the positive side as the steering angle θ _H increases, and the left wheel, which is the outer wheel, changes as the steering angle θ _H increases. Change to the negative side.

In the map shown in FIG. 6, the correction amount is set so as to cancel the change in the camber angle θ with respect to the steering angle θ _H. Camber angle θ for steering angle θ _H
The map shown in FIG. 6 will be correspondingly different if the change characteristics of the above are different. In any case, the correction amount Dθ _H is set so as to cancel the camber angle change with respect to the steering angle θ _H. This correction is applied to the steered wheels, that is, the front wheels.

The lateral acceleration corresponding correction amount setting unit 32C sets the control correction amount D _GY according to the lateral acceleration GY from the map as shown in FIG. This is because the camber angle θ changes in response to the rolling of the vehicle body, so that the camber angle θ is corrected. In FIG. 8, the horizontal axis represents the lateral acceleration G.
Y, the right side of the horizontal axis is the lateral acceleration to the right, the left side of the horizontal axis is the lateral acceleration to the left, the vertical axis shows the control correction amount D _GY , and the upper side of the vertical axis. The correction amount to the positive side, and the lower side of the vertical axis is the correction amount to the negative side. The solid line indicates the correction amount for the right wheel, and the chain line indicates the correction amount for the left wheel.

The change of the camber angle θ with respect to the steering angle θ _H is
Generally, for example, as shown in FIG. 7, the camber angle θ of the wheel on the roll direction side (the outer wheel side at the time of turning) changes to the positive side, and the side opposite to the roll direction (the inner wheel side at the time of turning).
The camber angle θ of the wheel of is changed to the negative side. Figure 7
The horizontal axis on the right side is the lateral acceleration to the right, the horizontal axis on the left side is the lateral acceleration to the left, the vertical axis on the upper side is the roll angle to the right, and the vertical axis on the lower side is the roll angle to the left. Shows the characteristic for the right wheel, and the chain line shows the characteristic for the left wheel. As shown in the figure, for example, when the vehicle body rolls to the right when turning left, the right wheel, which is the wheel on the roll direction side, changes to the positive side as the steering angle θ _H increases, and the side opposite to the roll direction. The left wheel, which is the wheel of, changes to the negative side as the steering angle θ _H increases.

In the map shown in FIG. 8, the correction amount is set so as to cancel the change in the camber angle θ with respect to the roll of the vehicle body. Therefore, if the change characteristic of the camber angle θ with respect to the roll of the vehicle body is different, the map shown in FIG. 8 is correspondingly different. In any case, the correction amount D _GY is set so as to cancel the camber angle change with respect to the vehicle body roll.

The setting of the control amount L by the camber angle control amount setting unit 32A and its output are performed by the preview sensor 3
Immediately after detecting unevenness of the road surface in 9 (after a minute required time), it is performed for a predetermined time, and at other times, 0 is output as the control amount L. In particular, when the unevenness detection information (ON information) of the preview sensor 39 is entered, the control amount L of the camber angle θ that sets the grounding kingpin offset to 0 for a short time in which each wheel gets over this unevenness while considering the control delay. It is desirable to output the output and then immediately set the control amount L to 0 to end the control of the camber angle θ for overcoming the protrusion.

To this end, when the preview sensor 39 outputs the ON information, the timing at which the front wheel or the rear wheel of the corresponding wheel (that is, the right wheel or the left wheel) gets over the unevenness is estimated according to the vehicle speed V. Then, the control amount L that makes the grounding pin offset to 0 may be output at this timing. The control amount L here corresponds to the amount by which the current camber angle is changed to the camber angle at which the grounding kingpin offset is set to 0. For example, the control valves 10, 12 only for a time corresponding to the control amount L. , 14 and 16 are set to the second position or the third position and then returned to the first position. Alternatively, while detecting the actual size of the camber angle or the length of the actuator corresponding thereto, the displacement sensors 42 to 42 are arranged so that these detected values become values corresponding to the control amount L.
It is also conceivable to perform feedback control based on the detected value of 48.

Since the vehicle camber angle control device as one embodiment of the present invention is configured as described above, the camber angle control amount L is set for each wheel as shown in FIG. 4, for example. It That is, the program processing according to the flowchart shown in FIG. 4 is started when the engine switch (ignition switch) (not shown) is turned on. First, parameters related to control are initially set (step S1), and detection signals concerning the presence of road surface irregularities, the steering angle θ, the vehicle speed V, the lateral acceleration GY, etc. are read from the respective sensors 36 to 50 (step S2).

In the next step S3, it is determined whether the signal from the preview sensor (road surface sensor) 39 is on. If the signal from the preview sensor 39 is on,
In step S4, the control amount L for reducing the disturbance sensitivity is set, but if the signal from the preview sensor 39 is not on, the control for reducing the disturbance sensitivity is not performed and the control cycle of this time is ended.

When the process proceeds to step S4, the steering angle θ is 0
Is larger than a threshold | θ ₀ | close to. If the steering angle θ is larger than the threshold value | θ ₀ |, it is determined that the vehicle is turning and the process proceeds to step S5, and the steering angle θ is the threshold value | θ ₀ |
If not larger, it is determined that the vehicle is traveling straight ahead, and the process proceeds to step S9. During turning, in step S5, a correction amount Dθ _H corresponding to the steering angle θ _H is set based on, for example, a map as shown in FIG. 6, and this is set as a correction amount L ′ (step S6), and continues. In step S7, the correction amount D _GY corresponding to the roll of the vehicle body is set based on, for example, a map shown in FIG. 8, and the correction amount D θ _H plus the correction amount D _GY is referred to as a correction amount L ′. Yes (step S8).

On the other hand, during straight running, in step S9,
The correction amount L'is set to 0. In this way, step S5
After the correction amount L'is set in step S8 or step S9, the target control amount L of the camber angle is added by adding the correction amount L'to the previously obtained initial control amount L ₀ in step S10. Set (= L '+ L ₀ ).

The operations of steps S2 to S10 described above are performed every predetermined control cycle, and the camber angle is sometimes appropriately controlled according to the traveling state of the vehicle and the state of the road surface on which the vehicle is traveling. Then, the controller 32 controls the actuator A (2 to 8) according to the control amount L so that the camber angle of each wheel becomes a required size.

By controlling the kingpin offset to 0 by setting the control amount L as described above, the disturbance sensitivity of the suspension with respect to road surface seams and other road surface irregularities is reduced, and the riding comfort of the vehicle is improved. In particular, the control amount is appropriately corrected to offset this effect according to the change in the camber angle due to the turning of the wheels during turning and the change in the camber angle due to the roll of the vehicle body. You can do it properly.

The above maps (see FIGS. 5 to 8)
Is an example, and various map modes can be considered based on each characteristic tendency of the vehicle.

[0041]

As described above in detail, according to the vehicle camber angle control device of the present invention, the camber angle adjusting mechanism capable of adjusting the camber angle by driving the constituent elements of the suspension of the wheel in the vehicle, The control means for controlling the camber angle adjusting mechanism according to the running state of the vehicle, and the road surface state detecting means for detecting unevenness of the traveling road surface in front of the vehicle, the control means, the road surface state When the detecting means detects the unevenness of the traveling road surface, the camber angle is set to a camber angle that can set the grounding kingpin offset of the wheel to 0 or a value close to 0 in order to reduce the input sensitivity to the vehicle of the unevenness of the road surface. By being configured to control the adjustment mechanism, when overcoming the unevenness existing on the road surface of the vehicle,
There is an advantage that the influence of the irregularities on the vehicle is reduced and the riding comfort of the vehicle can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a vehicle camber angle control device as an embodiment of the present invention.

FIG. 2 is a configuration diagram schematically showing an entire vehicle camber angle control device as one embodiment of the present invention.

FIG. 3 is a front view showing a suspension provided with a vehicle camber angle control device as one embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation of a vehicle camber angle control device as an embodiment of the present invention.

FIG. 5 is a graph showing an example of characteristics of a camber angle change depending on a steering angle in a vehicle.

FIG. 6 is a diagram showing an example of a map relating to setting of a control amount (correction amount) in the vehicle camber angle control device as one embodiment of the present invention.

FIG. 7 is a graph showing an example of characteristics of camber angle change due to roll of a vehicle body in a vehicle.

FIG. 8 is a diagram showing an example of a map relating to setting of a control amount (correction amount) in the vehicle camber angle control device as one embodiment of the present invention.

FIG. 9 is a schematic front view of a wheel portion for explaining the control principle of the vehicle camber angle control device as one embodiment of the present invention, where (A) shows an initial state and (B) shows a control state. Is shown.

FIG. 10 is a schematic plan view of a wheel portion for explaining the control principle of the vehicle camber angle control device as one embodiment of the present invention.

FIG. 11 is a graph illustrating the control principle of the vehicle camber angle control device as one embodiment of the present invention.

[Explanation of symbols]

2, 4, 6, 8, A Actuator for adjusting camber angle 10, 12, 14, 16 Electromagnetic control valve 18 Supply path 20 Pump 22 Discharge path 24 Oil reservoir 26 Accumulator 28 Relief valve 30 Drive circuit 32 As control means Controller 32A camber angle control amount setting unit 32B steering angle corresponding correction amount setting unit 32C lateral acceleration corresponding correction amount setting unit 34 ROM in controller 32 stroke sensor as stroke means 38 steering sensor (steering angle sensor) 39 road surface state detection Preview sensor (road surface sensor) as means 40 Vehicle speed sensor 42,44,46,48 Displacement sensor F Vehicle body S Strut type suspension strut W Wheel

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takao Morita 5-3-8, Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation

Claims (1)

[Claims] 1. A camber angle adjusting mechanism capable of adjusting a camber angle by driving a constituent element of a wheel suspension in a vehicle, and a control means for controlling the camber angle adjusting mechanism according to a traveling state of the vehicle. With the road surface condition detecting means for detecting unevenness of the traveling road surface in front of the vehicle, the control means, when the unevenness of the traveling road surface is detected by the road surface condition detecting means, the unevenness of the road surface to the vehicle is detected. The camber angle adjusting mechanism is configured to control the camber angle adjusting mechanism so that the grounding pin offset of the wheel can be set to 0 or a value close to 0 in order to reduce the input sensitivity. Corner control device.