JPH08113154A - Power steering control device of automobile - Google Patents

Abstract

PURPOSE: To improve the safety of a vehicle and the steering feeling, without making wasteful a power steering control device (PS control device, thereafter) depending on a car speed inductive control method or an engine rotation frequency inductive control method, which has been used conventionally, and in a simple structure. CONSTITUTION: A PS control device depending on a car speed inductive control method is composed by providing basically a car speed sensor 4, a PS control device 5, a solenoid valve 6, and a PS actuator 2 to set variable an assist force applied to the steering according to the driving condition of the solenoid valve 6. In this case, when the detecting contents of a steering angle sensor 7 and a yaw rate sensor 8 satisfy a specific content, an artificial car speed pulse corresponding to the output pulse of the car speed sensor 4 is produced through an artificial car speed pulse producing device 9, and the artificial car speed pulse is to be given to the PS control device 5 through a selector 10. In this case, the assist force set variable through the solenoid valve 6 is set as desired corresponding to the content of the artificial car speed pulse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering control device for an automobile, and more particularly to a vehicle speed or an engine rotation for varying the assist force applied to the steering of steering wheels in accordance with the traveling speed of the vehicle or the engine speed. The present invention relates to improvement of a power steering control device by a number sensitive control system.

[0002]

2. Description of the Related Art Such a power steering control device usually has a power assist mechanism for assisting the operation of a steering mechanism that steers the steered wheels in accordance with a steering operation. When the vehicle is traveling at a low speed, the assisting force of the power assisting mechanism is increased to reduce the steering force of the steering wheel. -As the traveling speed (vehicle speed) increases, the assist force by the power assist mechanism is gradually reduced and the steering force of the steering is gradually increased. By performing such control, the vehicle stability is ensured and the safety is improved especially at high speed running.

However, even with such a power steering control device, for example, steering operation that does not match the traveling speed is prevented, or the vehicle skids on a road surface having a low friction coefficient due to rain or snow. It is not possible to suppress the phenomenon that causes spin and drift.

Therefore, in the prior art, for example, actual Kaihei 1-1458 is used.
As seen in Japanese Patent Publication No. 82-A device that controls steering torque (assist force) even when a wheel slips to avoid instability of the state of the vehicle. Alternatively, as seen in Japanese Patent Application Laid-Open No. 3-16879: When the yaw rate that is not suitable for the steering operation is generated in the vehicle, by prompting the driver to operate the steering in order to correspond the two, A device that avoids instability. Etc. have been proposed.

[0005]

According to such a power steering control device, steering operation that does not match the traveling speed of the vehicle, skidding of the vehicle on a road surface having a low friction coefficient (low μ road), etc. can be achieved to some extent. It is certainly prevented, and even if it falls into such a state, it is certainly easy to recover the vehicle from that state.

However, in any of these conventional power steering control devices, it is necessary to change the configuration of the control device or the control algorithm itself in order to realize the steering torque (assist force) control.
There is a disadvantage that the control device which has been generally used until now is wasted.

Incidentally, as such a power steering control device, in addition to the vehicle speed sensitive control system described above, there is also an engine speed sensitive control system in which the steering torque (assist force) changes according to the engine speed. However, this situation is generally common.

The present invention has been made in view of the above-mentioned circumstances, and does not waste any control device based on the vehicle speed or the engine speed sensitive control system used up to now, and has a simple structure. An object of the present invention is to provide a power steering control device for an automobile, which can improve vehicle safety and steering feeling.

[0009]

In order to achieve such an object, in the invention according to claim 1, a steering mechanism for steering the steered wheels in response to a steering operation and a steering operation of the steering mechanism are assisted. Power assist means, vehicle speed or engine speed information detecting means for detecting vehicle speed or engine speed information of the vehicle, motion state detecting means for detecting motion state of the vehicle, and based on the detected motion state Pseudo information generating means for generating pseudo information corresponding to the vehicle speed or engine speed information, the detected vehicle speed or engine speed information, or the assist characteristic by the power assisting means according to the generated pseudo information. A power steering control device for an automobile is configured by including control means for changing.

According to a second aspect of the present invention, in the configuration of the first aspect of the invention, the motion state detecting means includes at least steering angle detecting means for detecting a steering angle of the steering wheel. The pseudo information generating means, when the detected steering angle indicates the vicinity of the center of the steering, generates pseudo information corresponding to vehicle speed or engine speed information for increasing the assisting force by the power assisting means. Configure as.

According to a third aspect of the present invention, in the configuration of the first aspect of the invention, the motion state detecting means is a steering angle detecting means for detecting a steering angle of the steering wheel, and a spin state of the vehicle. And a spin / drift detecting means for detecting the presence / absence of a drift state, wherein the pseudo information generating means detects the spin state by the spin / drift detecting means and the steering angle detecting means. When the steering angle is changing in the steering increasing direction, pseudo information corresponding to vehicle speed or engine speed information that reduces the assisting force by the power assisting means is generated.

According to a fourth aspect of the present invention, in the configuration of the first aspect of the invention, the motion state detecting means is steering angle detecting means for detecting a steering angle of the steering wheel, and a spin state of the vehicle. And a spin / drift detecting means for detecting the presence / absence of a drift state, wherein the pseudo information generating means detects the drift state by the spin / drift detecting means and the steering angle detecting means. When the steering angle is changed in the steering drift correction direction, pseudo information corresponding to vehicle speed or engine speed information for increasing the assisting force by the power assisting means is generated.

According to a fifth aspect of the invention, in the configuration of the first aspect of the invention, the motion state detecting means is steering angle detecting means for detecting a steering angle of the steering wheel, and a spin state of the vehicle. And a spin / drift detecting means for detecting the presence / absence of a drift state, wherein the pseudo information generating means detects the drift state by the spin / drift detecting means and the steering angle detecting means. When the steering angle is near the center of the steering wheel, pseudo information corresponding to vehicle speed or engine speed information for increasing the assisting force by the power assisting means is generated, and at other times when the drift state is detected, Corresponding to vehicle speed or engine speed information to reduce the assist force by the power assist means. Constituting as generating pseudo information.

According to a sixth aspect of the invention, in the configuration of the first aspect of the invention, the motion state detecting means is provided with at least road surface gradient detecting means for detecting a gradient of the traveling road surface. Then, the pseudo information generating means uses pseudo information corresponding to vehicle speed or engine speed information for varying the assist force by the power assist means depending on whether the detected road surface slope indicates an uphill or a downhill. To generate.

According to a seventh aspect of the present invention, in the configuration of the first aspect of the invention, the motion state detecting means includes at least vehicle speed change detecting means for detecting a vehicle speed change of the vehicle. Then, the pseudo-information generating means generates pseudo-information corresponding to vehicle speed or engine speed information for varying the assist force by the power assist means depending on whether the detected vehicle speed change indicates acceleration or deceleration. Configure as what you want to generate.

Further, in the invention of claim 8, in the configuration of the invention of claim 1, the motion state detecting means includes at least means for detecting whether or not the antilock brake system control of the vehicle is activated. And the pseudo-information generating means is a pseudo-information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting means variable depending on whether or not the detected antilock brake system control is operated. Configure to generate information.

According to a ninth aspect of the present invention, in the configuration of the first aspect of the invention, the motion state detecting means includes at least means for detecting whether or not the traction control of the vehicle is operating. The pseudo information generating means is configured to generate pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting means variable depending on whether or not the detected traction control is operated. Configure.

According to the tenth aspect of the invention, there is provided a steering mechanism for steering the steered wheels in response to a steering operation, and a power assist means for assisting the steering operation of the steering mechanism. Alternatively, as a power steering control device for a vehicle in which the assist characteristic of the power assist means is variable according to the engine speed information, pseudo information corresponding to the desired assist characteristic of the power assist means is used as the vehicle speed or engine speed information. The pseudo information generating means for generating and outputting is provided.

[0019]

The control device based on the vehicle speed or engine speed sensitive control system usually includes the steering mechanism, the power assist means, the vehicle speed or engine speed information detecting means, and the power assist according to the detected vehicle speed or engine speed information. The control means is configured to change the assist characteristic of the means.

Therefore, as in the invention according to claim 1, (a) a motion state detecting means for detecting a motion state of the vehicle. (B) Pseudo information generating means for generating pseudo information corresponding to the vehicle speed or engine speed information based on the detected motion state. When the pseudo information generated by the pseudo information generating means is given to the control means, the assist characteristic of the power assisting means changes according to the content generated as the pseudo information. Become.

That is, a desired assist characteristic can be set based on the generation content of the above pseudo information with a very simple structure using a control device based on the vehicle speed or engine speed sensitive control system, and the steering force ( torque)
It becomes possible to obtain the characteristics.

Here, the correspondence between the motion state detected by the motion state detecting means and the generated pseudo information is arbitrary. For example, according to the invention of claim 2, (a1) motion state detection The means detects a steering angle of the steering wheel. (B1) The pseudo information generating means generates pseudo information corresponding to vehicle speed or engine speed information for increasing the assisting force by the power assisting means when the detected steering angle indicates the vicinity of the center of the steering. If so, the required steering force (torque) becomes light at least near the center of the steering wheel, and the center of the steering wheel will not be lost even when a turning operation is performed.

Further, as a correspondence between the detected motion state and the generated pseudo information, for example, according to the invention of claim 3, (a2) the motion state detecting means includes the steering angle of the steering wheel and the steering angle of the steering wheel. The presence / absence of a spin state and a drift state of the vehicle is detected. (B2) The pseudo information generating means is configured to detect the spin state by the spin / drift detecting means, and when the steering angle detected by the steering angle detecting means is changing in the steering increasing direction, the power assisting means. The pseudo information corresponding to the vehicle speed or the engine speed information for reducing the assist force by is generated. Assuming that, when the vehicle is in the spin state, even if an attempt is made to operate the steering wheel in the additional direction, a reaction force acts so that the required steering force (torque) becomes heavy. That is, such a reaction force can prompt the driver to perform an appropriate steering operation, and the spin state can be easily removed.

Also, as a correspondence between the detected motion state and the generated pseudo information, for example, the claim 4 may be adopted.
As in the invention described above, (a3) the motion state detecting means detects the steering angle of the steering wheel and the presence / absence of a spin state and a drift state of the vehicle. (B3) The pseudo information generating means is configured to detect the drift state by the spin / drift detecting means, and when the steering angle detected by the steering angle detecting means is changing in the steering drift correction direction, the power assisting means. The pseudo information corresponding to the vehicle speed or the engine speed information for increasing the assisting force is generated. If so, the required steering force (torque) is reduced when the vehicle is in a drift state and the steering is operated in a direction to correct it. That is, such a correction operation is supported, and it becomes easy to get out of the drift state.

Further, as a correspondence between the detected motion state and the generated pseudo information, for example, claim 5
As described above, (a4) the motion state detecting means detects the steering angle of the steering wheel and the presence or absence of a spin state and a drift state of the vehicle. (B4) When the drift state is detected by the spin / drift detection means and the steering angle detected by the steering angle detection means indicates the vicinity of the center of the steering, the pseudo information generation means provides the assist force by the power assist means. Pseudo information corresponding to vehicle speed or engine speed information that generates pseudo information corresponding to the vehicle speed or engine speed information to be increased, and reduces the assist force by the power assisting means at other times when the drift state is detected. To generate. In this case, even if the vehicle is in a drift state and an attempt is made to perform a correction operation thereof, the required steering force (torque) is reduced near the center of the steering wheel, and the center of the steering wheel is not lost.

Incidentally, if the center of the steering wheel is lost and the corrected steering amount becomes too large when the vehicle is in a drift state, there is a danger that the vehicle will move into a spin state and the vehicle motion will diverge.

Further, as a correspondence between the detected motion state and the generated pseudo information, for example, as in the invention according to claim 6, (a5) the motion state detecting means detects the gradient of the traveling road surface. To do. (B5) The pseudo information generating means is pseudo information corresponding to vehicle speed or engine speed information for varying the assist force of the power assist means depending on whether the detected road surface slope indicates an uphill or a downhill. To generate. With this structure, it is possible to preferably eliminate the change in the steering torque according to the vehicle characteristics such as the road surface gradient and the suspension characteristics. In particular, the pseudo information generating means: When the detected road surface slope indicates an uphill slope, generates pseudo information corresponding to vehicle speed or engine speed information that reduces the assisting force by the power assisting means,
When the detected road surface slope indicates a downhill, pseudo information corresponding to vehicle speed or engine speed information for increasing the assist force by the power assist means is generated. If this is the case, the load movement due to the road surface slope will cause: ・ The required steering force (torque) will be reduced when climbing.・ The required steering force (torque) becomes heavy on the downhill. It is possible to eliminate the change in the steering force in such a manner.

Also, as a correspondence between the detected motion state and the generated pseudo information, for example, the claim 7
As in the invention described above, (a6) the motion state detecting means detects a change in vehicle speed of the vehicle. (B6) The pseudo information generating means generates pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assist means variable depending on whether the detected vehicle speed change indicates acceleration or deceleration. To generate. If so, it becomes possible to preferably eliminate the change in the steering torque according to the vehicle characteristics such as the vehicle speed variation and the suspension characteristic. Also in this case, in particular, when the detected vehicle speed change indicates acceleration, the pseudo information generating means generates pseudo information corresponding to vehicle speed or engine speed information for reducing the assisting force by the power assisting means. Then
When the detected vehicle speed change indicates deceleration, pseudo information corresponding to vehicle speed or engine speed information for increasing the assisting force by the power assisting means is generated. If this is the case, the load shift due to the change in vehicle speed will:・ Required steering force (torque) becomes heavy during deceleration. It is possible to eliminate the change in the steering force in such a manner.

Furthermore, as a correspondence between the detected motion state and the generated pseudo information, for example, according to the invention of claim 8, (a7) the motion state detecting means is an antilock brake for the vehicle. Detects the presence or absence of system control operation. (B7) The pseudo information generating means generates pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting means variable depending on whether or not the detected antilock brake system control is operated. . Alternatively, or as in the invention according to claim 9, (a8) the motion state detecting means detects whether or not the traction control of the vehicle is activated. (B8) The pseudo information generating means generates pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting means variable depending on whether or not the detected traction control is activated. Therefore, even when the vehicle is at the braking limit or the acceleration limit during the anti-lock brake system (ABS) control or the traction (TRC) control, that effect can be appropriately transmitted to the driver. become able to. In this case, basically, it is desirable to generate pseudo information corresponding to the vehicle speed or the engine speed information in a direction in which the assist force is small, that is, the required steering force (torque) is heavy.

By the way, in the power steering control device based on the conventional vehicle speed or engine speed sensitive control system, for example, when it is necessary to change the assist characteristic itself, the resistance value in the control device is changed. I was forced to make a hardware change.

Therefore, as in the tenth aspect of the present invention, (c) pseudo information generating means for generating and outputting pseudo information corresponding to a desired assist characteristic of the power assist means as vehicle speed or engine speed information. Also in this case, in this case as well, a very simple configuration in which the control device based on the vehicle speed or the engine speed sensitive control system is diverted as it is, so to speak, as software, the desired assist based on the generation content of the above pseudo information is provided. You will be able to set and change the characteristics.

[0032]

FIG. 1 shows an embodiment of a power steering control device for an automobile according to the present invention.

In the device of this embodiment, the power steering (hereinafter simply referred to as PS) control device based on the vehicle speed sensitive control system that has been used up to now is diverted as it is, and the steering is performed regardless of the motion state of the vehicle. It is configured as a device capable of suitably variably setting the assist force applied to the.

First, the configuration of the apparatus of this embodiment will be described with reference to FIG. In FIG. 1, a steering wheel 1, a PS actuator 2, left and right steered wheels 3L and 3 are shown.
The R, the vehicle speed sensor 4, the PS control device 5, and the solenoid valve 6 arranged on the PS actuator 2 constitute a known PS control device based on a vehicle speed sensitive control system.

Incidentally, the PS actuator 2 is a steering mechanism composed of a well-known hydraulic circuit for steering the steered wheels 3L and 3R according to the operation of the steering wheel 1 and a gearbox, and the assist force applied to the steering operation is , And varies according to the drive mode (hydraulic flow rate adjustment mode) of the solenoid valve 6.

The solenoid valve 6 is composed of a linear solenoid capable of fixing the valve element at an arbitrary position proportional to the average current of the duty signal given from the PS controller 5 as the control signal PSC.

Further, the vehicle speed sensor 4 is provided in the speedometer, the axle, etc., and the traveling speed (vehicle speed) V of the vehicle concerned.
This is a sensor that outputs a vehicle speed pulse having a frequency (cycle) proportional to, and the PS control device 5 generates a duty signal whose average value increases in proportion to the vehicle speed V as the control signal PSC.

After all, a steering assist force corresponding to the vehicle speed V of the vehicle can be obtained through the PS actuator 2 through a series of operations by the vehicle speed sensor 4, the PS control device 5, and the solenoid valve 6. In addition, PS
Although it depends on the structure of the actuator 2, here, the larger the average current as the control signal PSC, the larger the opening degree of the solenoid valve 6, and the smaller the assist force (the steering force required for the steering 1 or the steering torque is heavier). Is supposed to be.

On the other hand, in the apparatus of this embodiment shown in FIG. 1, the steering angle sensor 7 is a sensor for detecting the rotation angle of the steering wheel 1, that is, the steering angle MA, and the yaw rate sensor 8 is for the vehicle. This is a sensor that detects the yaw rate x.

The detected steering angle MA and yaw rate x are both input to the pseudo vehicle speed pulse generator 9 as a signal indicating the motion state of the vehicle. Further, the pseudo vehicle speed pulse generation device 9 is based on the detected motion state (steering angle MA and yaw rate x) and the vehicle speed pulse V detected by the vehicle speed sensor 4, and the pseudo vehicle speed pulse corresponding to the vehicle speed pulse V. It is a device that generates a GV and that is configured by, for example, a microcomputer.

The generated pseudo vehicle speed pulse GV is input to the PS control device 5 via the selector 10 including an OR circuit OR, AND circuits AND1 and AND2, and an inverter IV.

The selector 10 selectively selects the vehicle speed pulse V output from the vehicle speed sensor 4 when the switching signal SL output from the pseudo vehicle speed pulse generator 9 is at the logical "L (low)" level. 5 and the same switching signal S
This circuit selectively applies the generated pseudo vehicle speed pulse GV to the PS control device 5 when L becomes the logic "H (high)" level. The switching signal SL is normally set to a logical "L" level for selecting the vehicle speed pulse V.

When the pseudo vehicle speed pulse GV is applied to the PS controller 5 in this manner, the PS controller 5 uses, as the control signal PSC, a duty signal whose average value increases in proportion to the frequency of the pseudo vehicle speed pulse GV. Will be generated.

FIG. 2 shows a procedure for generating the pseudo vehicle speed pulse GV by the pseudo vehicle speed pulse generator 9.
Next, the PS control method by the apparatus of this embodiment will be described in more detail with reference to FIG.

That is, assuming that the pseudo vehicle speed pulse generation device 9 is activated when the vehicle is turned on, the pseudo vehicle speed pulse generation device 9 first receives the vehicle speed V from the sensors 4, 7, and 8, respectively. , Steering angle M
Input A and the actual yaw rate x of the vehicle (step 1
00). Then, based on the vehicle speed V and the steering angle MA among these input sensor values, a target yaw rate xref suitable for the vehicle speed V and the steering angle MA at that time is calculated as xref = (1 / NL) · {V / (1 + KhV ^ 2)} · MA (1) However, N: Steering gear ratio L: Vehicle wheel base length Kh: Stability factor Further, “^” represents exponentiation (“^ 2” is square). Step 101).

The pseudo vehicle speed pulse generator 9 which has calculated the target yaw rate xref in this way then finds the deviation Δx as Δx = xref-x (2) based on the target yaw rate xref and the detected actual yaw rate x. At the same time, a parameter Δx ′ for determining whether the appropriate yaw rate is in the area where the yaw rate is not output or the area where the yaw rate is excessive is output is Δx ′ = sgn (x) · (xref−x) (3) And the sign of the parameter Δx ′ (sgn: + /
The presence / absence of the spin state and the drift state of the vehicle is determined based on −) (step 102).

Here, in the embodiment, the spin state of the vehicle is defined as the state in the "A" region of the graph shown in FIG. 3, and the drift state is also "B" of the graph shown in FIG. It is defined as a state in the area.

That is, FIG. 3A shows an example of the relationship between the target yaw rate xref and the actual yaw rate x determined based on the steering operation with time at a certain vehicle speed, and the area "A" in the figure shows Target yaw rate xr
A state in which a yaw rate suitable for the actual yaw rate x is not obtained with respect to ef is shown. In this state, the yaw rate does not increase even if the steering wheel 1 is turned off.
In this embodiment, the state in this area "A" is the spin state. On the other hand, the area "B" in the figure shows a state in which an excessive yaw rate as the actual yaw rate x with respect to the target yaw rate xref is generated. This state is, so to speak, a state in which the yaw rate increases more than when the steering wheel 1 is turned off. In the same embodiment, the state in this region "B" is the drift state.

The deviation Δx between the target yaw rate xref and the actual yaw rate x corresponds to the example shown in FIG. 3 (b).
The embodiment shown in FIG. That is, this deviation Δx
Is obtained as a positive value, the vehicle is in a spin state, and when the deviation Δx is obtained as a negative value, the vehicle is in a drift state.

Therefore, as in the above equation (3),
Alternatively, as shown in FIG. 4, the parameter Δx ′ (= s
By determining gn (x) · (xref−x)), it becomes possible to determine the presence or absence of the spin state and the drift state from the value (sign).

When the presence / absence of the spin state and the drift state is thus determined in the pseudo vehicle speed pulse generation device 9, the pseudo vehicle speed pulse GV is generated in the modes listed below based on the result of the determination, and the PS control device 5 is informed. Output. (1) When it is determined that the steering wheel is in the spin state and that the steering wheel 1 is being operated in the increasing direction: P
A pulse frequency corresponding to the frequency of the vehicle speed pulse V that reduces the assist force through the S actuator 2 (reduces the required steering force or steering torque) is map-calculated (steps 110 and 111).

Incidentally, in the vehicle speed sensitive control type PS control apparatus which is the target of the apparatus of the embodiment, for example, the relationship between the vehicle speed V (vehicle speed pulse frequency) and the steering torque MT is shown in the mode shown in FIG. Is set.

Therefore, here, a pulse frequency corresponding to a relatively high vehicle speed V (vehicle speed pulse frequency) at which a predetermined heavy steering torque MT is obtained by utilizing the characteristics of the vehicle speed-steering torque characteristic, for example, in the Z region. Map calculation.

After that, the switching signal SL is raised to the logic "H" level, the pseudo vehicle speed pulse GV is generated at the calculated frequency, and the pseudo vehicle speed pulse GV is output to the PS controller 5 (step 130). ).

As a result, the PS control device 5 generates a signal as the control signal PSC for instructing to reduce the assist force (necessary steering force or steering torque is heavy) based on the pseudo vehicle speed pulse GV, and drives the solenoid valve 6. To do.

As described above, when the steering 1 is operated in the increasing direction while the vehicle is in the spin state, the control is performed so that the reaction force acts so that the required steering force or steering torque becomes heavy. . Through such a reaction force, the driver can be prompted to perform an appropriate steering operation, and thus the spin state can be easily removed. (2) When it is determined that the vehicle is in the drift state and the detected steering angle MA is changing in the drift correction direction of the steering wheel 1: The assist force through the PS actuator 2 is increased (the required steering force or A map calculation is performed on the pulse frequency corresponding to the frequency of the vehicle speed pulse V that reduces the steering torque (steps 120 and 121 and 122 and 123).

Also in this case, the map calculation is executed by utilizing the characteristic of the vehicle speed-steering torque characteristic, for example, in the Z region. However, in this case, the pulse frequency corresponding to the vehicle speed V (vehicle speed pulse frequency) of a relatively low speed at which a predetermined light steering torque MT is obtained is map-calculated.

After that, the switching signal SL is raised to the logic "H" level, the pseudo vehicle speed pulse GV is generated at the calculated frequency, and the pseudo vehicle speed pulse GV is output to the PS controller 5 (step 130). ).

As a result, the PS control device 5 generates a signal as the control signal PSC for instructing to increase the assist force (reduce the necessary steering force or steering torque) based on the pseudo vehicle speed pulse GV, and drives the solenoid valve 6. To do.

As described above, when the steering 1 is operated in the correction direction while the vehicle is in the drift state,
The necessary steering force or steering torque is reduced, and control is performed to facilitate the same correction steering. Therefore, it is possible to easily get out of the drift state. (3) When it is determined that the vehicle is in the drift state and the detected steering angle MA does not change in the drift correction direction of the steering wheel 1: The assist force through the PS actuator 2 is reduced (the required steering force or The map calculation is performed on the pulse frequency corresponding to the frequency of the vehicle speed pulse V that makes the steering torque heavy (steps 120, 121, 122 and 124).

Also in this case, the map calculation is executed by utilizing the characteristic of the vehicle speed-steering torque characteristic, for example, in the Z region. Then, as in the case of the above (1), the map calculation is performed on the pulse frequency corresponding to the relatively low vehicle speed V (vehicle speed pulse frequency) at which the predetermined heavy steering torque MT is obtained.

After that, the switching signal SL is raised to the logic "H" level, the pseudo vehicle speed pulse GV is generated at the calculated frequency, and the pseudo vehicle speed pulse GV is output to the PS controller 5 (step 130). ).

As a result, the PS control device 5 generates a signal as a control signal PSC for instructing to reduce the assist force (necessary steering force or steering torque is heavy) based on the pseudo vehicle speed pulse GV, and drives the solenoid valve 6. To do.

As described above, when the steering 1 is not operated in the correction direction when the vehicle is in the drift state, the control is performed so that the reaction force acts so that the required steering force or steering torque becomes heavy. . Therefore, also in this case, it is possible to prompt the driver to perform an appropriate steering operation through the reaction force, and it is possible to easily get out of the drift state. (4) When it is determined that the vehicle is in the drift state and the detected steering angle MA indicates the vicinity of the center of the steering wheel 1: The assist force through the PS actuator 2 is increased (the required steering force or steering torque is reduced). The pulse frequency corresponding to the frequency of the vehicle speed pulse V is calculated (steps 120, 121 and 125).

In this case, it is assumed that the frequency of the pseudo vehicle speed pulse GV is calculated based on the map shown in FIG. That is, FIG. 6A is a map that is preset in the apparatus of the same embodiment regarding the relationship between the steering angle MA and the steering torque MT when the drift amount is constant (const.), And is calculated as described above, for example. Deviation Δx
By determining the amount of drift at that time based on
The target value of the steering torque MT corresponding to the steering angle MA at that time is first determined.

On the other hand, FIG. 6 (b) is a map set in correspondence with the characteristics of the Z region portion of the vehicle speed-steering torque characteristics shown in FIG. 5 above, and through the map illustrated in FIG. 6 (a). By determining the target value of the steering torque MT, the frequency of the pseudo vehicle speed pulse GV corresponding to the steering torque MT can be obtained through the map of FIG. 6 (b).

Therefore, when the detected steering angle MA indicates the vicinity of the center of the steering 1 as in the example here, the target value of the steering torque MT is set so that the steering angle MA indicates the center direction. A light value is selected, and a low pulse frequency is selected corresponding to the selected steering torque MT.

After that, as before, the switching signal SL is raised to the logical "H" level, the pseudo vehicle speed pulse GV is generated at the selected frequency, and the pseudo vehicle speed pulse GV is output to the PS controller 5. (Step 130).

As a result, the PS control device 5 generates a signal as a control signal PSC for instructing to increase the assist force (reduce the necessary steering force or steering torque) based on the pseudo vehicle speed pulse GV, and drives the solenoid valve 6. To do.

In this case, however, as is clear from the map illustrated in FIG. 6, when the steering angle MA is not near the center of the steering wheel 1, a heavy value is selected as the target value of the steering torque MT and the selection is made. A high pulse frequency is selected in accordance with the selected steering torque MT. Therefore, in that case, the PS control device 5 outputs the control signal PSC for instructing to reduce the assist force (increase the required steering force or steering torque).

As described above, when the steering 1 is operated near the center when the vehicle is in the drift state, the PS control is performed so that the required steering force or steering torque is reduced. Therefore, even when the vehicle is in the drift state and an attempt is made to perform a correction operation thereof, the center of the steering wheel 1 will not be lost.
In the case where the vehicle is in such a drift state, if the center of the steering wheel 1 is lost and the corrected steering amount becomes too large, there is a risk of reaching a spin state and diverging the vehicle motion. As I did.

In consideration of the above case (2),
When the steering wheel 1 is operated in the correction direction in such a drift state, the required steering force or steering torque becomes lighter, but when the steering wheel 1 is operated near this center, the required steering force or steering torque becomes lighter. It shall be controlled to further promote. (5) When neither spin state nor drift state is determined: In this case, the routine is once exited without generating the pseudo vehicle speed pulse GV (step 120).

That is, the PS according to the normal vehicle speed sensitive control system based on the vehicle speed pulse V output from the vehicle speed sensor 4
Control comes into play. As described above, according to the PS control device of this embodiment, the P control by the vehicle speed sensitive control system is performed.
By using the S control device as it is, it becomes possible to add a PS control function for improving the safety of the vehicle and the steering feeling.

In the apparatus of the present embodiment, when the steering 1 is operated near the center when the vehicle is in a drift state, PS control is performed so that the required steering force or steering torque is reduced. However, such PS control can be adopted regardless of the motion state of the vehicle.

That is, when the steering wheel 1 is operated in the vicinity of the center, the PS control may be performed so that the required steering force or steering torque is always reduced. By doing so, the center of the steering wheel 1 will not be lost in any case, and the driver can be urged to perform more stable steering operation not only during turning operation but also during normal traveling.

Further, as indicated by a broken line in FIG. 1, as a sensor for detecting the motion state of the vehicle, an appropriate sensor for detecting the gradient of the traveling road surface is further provided, and in the pseudo vehicle speed pulse generation device 9, Based on the detected road surface gradient information, (a) When the detected road surface gradient indicates an uphill slope, the assist force through the PS actuator 2 is reduced (the required steering force or steering torque is increased). (B) When the detected road surface slope indicates a downhill, the assist force through the PS actuator 2 is increased (the required steering force or steering torque is decreased). The pseudo vehicle speed pulse GV may be generated.

As a result, due to the movement of the load due to the road gradient, the required steering force (torque) is reduced when climbing.・ The required steering force (torque) becomes heavy on the downhill. It is possible to eliminate the change in the steering force in such a manner.

With respect to such a road surface gradient, the required steering force (torque) depends on the suspension characteristics of the vehicle, etc.
It may change depending on the vehicle characteristics. In consideration of such vehicle characteristics, it may be effective in some cases to reverse these PS control modes. The point is that the assisting force by the power assisting means may be varied depending on whether the detected road gradient indicates an uphill or a downhill.

Similarly, as a sensor for detecting the motion state of the vehicle, an appropriate sensor for detecting the longitudinal acceleration of the vehicle is further provided. In the pseudo vehicle speed pulse generation device 9, the detected vehicle speed change information is provided. (A) When the detected vehicle speed change indicates acceleration, the assist force through the PS actuator 2 is reduced (the required steering force or steering torque is increased). (B) When the detected vehicle speed change indicates deceleration, the assist force through the PS actuator 2 is increased (the required steering force or steering torque is decreased). The pseudo vehicle speed pulse GV may be generated.

As a result, the load is moved due to the change in vehicle speed. The required steering force (torque) is reduced during acceleration.・ Required steering force (torque) becomes heavy during deceleration. It becomes possible to eliminate the change in the steering force in such a manner.

Even with such changes in vehicle speed, the required steering force (torque) may change according to vehicle characteristics such as the suspension characteristics of the vehicle. Also in this case, it may be effective to reverse these PS control modes. Therefore, also in this case, the configuration may be such that the assisting force by the power assisting means is variable depending on whether the detected vehicle speed change indicates acceleration or deceleration.

On the other hand, as also indicated by a broken line in FIG. 1, the presence or absence of the operation of ABS (anti-lock brake system) control, which is well-known as the motion state of the vehicle, is detected, and the detected ABS control operation is detected. Pseudo vehicle speed pulse GV in which the assist force by the PS actuator 2 is variable depending on the presence or absence
Generate Structure, or TRC (traction), which is well known as the motion state of the vehicle
The presence / absence of control operation is detected, and a pseudo vehicle speed pulse GV for varying the assist force by the PS actuator 2 is generated according to the detected presence / absence of TRC control operation. It can also be configured. According to these configurations, ABS
Even when the vehicle is in the braking limit or the acceleration limit during the control or the TRC control, the fact can be appropriately transmitted to the driver.

In this case, basically, it is necessary to generate the pseudo vehicle speed pulse GV in a direction in which the assist force is small, that is, the required steering force (torque) is heavy. It is desirable to enhance the ring.

When the PS control according to the presence / absence of the ABS control or TRC control operation and the PS control based on the spin / drift determination described above are used in combination, the priority is (1) spin / drift. PS control based on judgment (2) PS control depending on whether ABS control is activated (3) PS control depending on whether TRC control is activated It is important to set vehicle safety and steering. It is desirable to improve the feeling.

Further, in the apparatus of the above embodiment, the yaw rate sensor 8 is used to detect the yaw rate of the vehicle. However, instead of the yaw rate sensor 8, a lateral momentum of the vehicle is detected. An acceleration sensor may be used. This also makes it possible to perform spin / drift determination substantially equivalent to that of the apparatus of the above embodiment.

In the apparatus of the above embodiment, the vehicle speed pulse V which is the output of the vehicle speed sensor 4 and the pseudo vehicle speed pulse GV generated above are selected by the selector 10 and taken into the PS controller 5. The configuration for selectively capturing these pulses in the PS control device 5 is arbitrary.
In addition, for example, an appropriate modulator is provided in place of the selector 10, and when the pseudo vehicle speed pulse GV is required, the vehicle speed pulse V is modulated as needed by the generated pseudo vehicle speed pulse GV or its frequency information. The PS control device 5 uses the modulated pulse as a pseudo vehicle speed pulse GV.
It is also possible to adopt a configuration in which

The PS controller 5, the pseudo vehicle speed pulse generator 9, the selector 10, and the modulator described above may be realized as one or a plurality of electronic controllers that combine them. Of course good.

By the way, in the PS control device based on the conventional vehicle speed sensitive control system, when it is necessary to change the assist characteristic itself illustrated in FIG. 5, for example, the resistance value in the control device is changed. I was forced to make a hardware change.

However, according to the configuration including the pseudo vehicle speed pulse generating device 9 as in the device of the above-described embodiment, or in accordance with the pseudo vehicle speed pulse generating device 9, an arbitrary pseudo vehicle speed pulse GV is generated and output, so to speak, pseudo. According to the configuration including the information generator, the assist characteristic can be arbitrarily changed by software through the pseudo information conversion or generation map (table). Of course, in this case as well, the PS control device based on the vehicle speed sensitive control system used so far can be used as it is.

In the above embodiment, the case where the present invention is applied to the PS control device based on the vehicle speed sensitive control system is described for the sake of convenience. However, the PS based on the engine speed sensitive control system in which the assist force changes according to the engine speed. The control device has the same basic configuration. Therefore, the present invention can be applied to the PS control device based on such an engine speed sensitive control system in a mode according to the above, and the same effect as described above can be obtained.

[0091]

As described above, according to the present invention, the control device based on the vehicle speed or engine speed sensitive control system which has been used up to now is not wasted, and pseudo information is given to the control device. With such a simple configuration, it becomes possible to improve the safety of the vehicle and the steering feeling.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a PS control device according to the present invention.

FIG. 2 is a flowchart showing a pseudo vehicle speed pulse generation procedure according to the embodiment.

FIG. 3 is a graph showing a spin / drift determination method.

FIG. 4 is a graph showing a spin / drift determination mode according to the example.

FIG. 5 is a graph showing a power steering control characteristic by a vehicle speed sensitive system.

FIG. 6 is a graph showing a vehicle motion state-pseudo vehicle speed information conversion mode of the embodiment.

[Explanation of symbols]

1 ... Steering, 2 ... PS actuator, 3 (3
L, 3R) ... Steering wheels, 4 ... Vehicle speed sensor, 5 ... PS controller, 6 ... Solenoid valve, 7 ... Steering angle sensor, 8 ... Yaw rate sensor, 9 ... Pseudo vehicle speed pulse generator, 10 ... Selector.

Claims (10)

[Claims] 1. A steering mechanism for steering steered wheels according to a steering operation, a power assist means for assisting the steering operation of the steering mechanism, a vehicle speed for detecting the vehicle speed or engine speed information of the vehicle, or Engine speed information detecting means, motion state detecting means for detecting a motion state of the vehicle, and pseudo information generating means for generating pseudo information corresponding to the vehicle speed or engine speed information based on the detected motion state. And a control means for changing the assist characteristic of the power assist means in accordance with the detected vehicle speed or engine speed information or the generated pseudo information, and a power steering control for an automobile. apparatus. 2. The motion state detecting means comprises at least a steering angle detecting means for detecting a steering angle of the steering wheel, and the pseudo information generating means is arranged so that the detected steering angle indicates a vicinity of a center of the steering wheel. And generating pseudo information corresponding to vehicle speed or engine speed information for increasing the assisting force by the power assisting means.
A power steering control device for an automobile as described. 3. The motion state detecting means includes a steering angle detecting means for detecting a steering angle of the steering wheel, and a spin / spin detecting means for detecting presence / absence of a spin state and a drift state of the vehicle.
The pseudo-information generating means includes at least a drift detecting means, and the spin information is detected by the spin / drift detecting means, and the steering angle detected by the steering angle detecting means is changed in the steering turning direction. At this time, the power steering control device for a vehicle according to claim 1, wherein pseudo information corresponding to vehicle speed or engine speed information for reducing the assisting force by the power assisting means is generated. 4. The motion state detecting means includes a steering angle detecting means for detecting a steering angle of the steering wheel, and a spin / spin state detecting presence / absence of a spin state and a drift state of the vehicle.
The pseudo information generating means includes at least a drift detecting means, and the spin information / drift detecting means detects a drift state, and the steering angle detected by the steering angle detecting means is changed in the steering drift correction direction. At this time, the power steering control device for a vehicle according to claim 1, wherein pseudo information corresponding to vehicle speed or engine speed information for increasing the assisting force by the power assisting means is generated. 5. The motion state detecting means includes a steering angle detecting means for detecting a steering angle of the steering wheel, and a spin / spin state detecting presence / absence of a spin state and a drift state of the vehicle.
The pseudo information generating means includes at least a drift detecting means, and when the spin state / drift detecting means detects a drift state and the steering angle detected by the steering angle detecting means indicates a vicinity of the center of the steering, The vehicle speed or engine speed that reduces the assist force by the power assisting means at other times when pseudo information corresponding to the vehicle speed or engine speed information that increases the assisting force by the assisting means is generated and the drift state is detected. The power steering control device for an automobile according to claim 1, wherein pseudo information corresponding to the information is generated. 6. The motion state detecting means includes at least road surface slope detecting means for detecting a slope of the traveling road surface, and the pseudo information generating means determines whether the detected road surface slope indicates uphill or downhill. The power steering control device for a vehicle according to claim 1, wherein pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting means variable is generated at the time of indicating. 7. The motion state detecting means includes at least a vehicle speed change detecting means for detecting a vehicle speed change of the vehicle, and the pseudo information generating means indicates when the detected vehicle speed change indicates acceleration and deceleration. 2. The power steering control device for a vehicle according to claim 1, wherein pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting means variable is generated. 8. The motion state detecting means includes at least means for detecting whether or not the antilock brake system control of the vehicle is operated, and the pseudo information generating means includes the detected antilock brake system control operation. 2. The power steering control device for a vehicle according to claim 1, wherein pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting device variable is generated according to the presence or absence of the above. 9. The motion state detecting means includes at least means for detecting whether or not traction control of the vehicle is operating, and the pseudo-information generating means is operable to detect the traction control of the vehicle according to whether or not the traction control is operating. The power steering control device for a vehicle according to claim 1, wherein pseudo information corresponding to vehicle speed or engine speed information that makes the assisting force by the power assisting means variable is generated. 10. A steering mechanism that steers the steered wheels in response to a steering operation, and a power assisting unit that assists the steering operation of the steering mechanism. According to vehicle speed or engine speed information of the vehicle. In a power steering control device for a vehicle in which the assist characteristic of the power assist means is variable, pseudo information generating means for generating and outputting pseudo information corresponding to a desired assist characteristic of the power assist means as the vehicle speed or engine speed information. A power steering control device for an automobile, which is characterized by comprising: