JPH08295256A - Steering controller - Google Patents

Abstract

PURPOSE: To suppress a vibration of a control valve or rack bar by specifying a vibration generating mode at a time when any vibration is produced in a steering gear part, and altering steering auxiliary force according to the vibration generating mode so as to get the vibration produced in the steering gear part suppressed. CONSTITUTION: Each signal to be outputted from various sensors to be connected to a power steering computer 48 is read out and thereby a calculation of steering speed takes place. After this calculation, on the basis of an output signal out of a vertical G sensor 50, a judgment of whether there is a vertical vibration in a steering gear part 49 or not is carried out. When such a vibration as exceeding the specified value is generated in this steering gear part 49, a fact of whether this vibration is a self-excited vibration in a control valve 16 or a vibration in a rack bar 26 is judged. On the basis of this judgment, a compensation with a control value found out by the generative modes of the vibration is carried out, whereby an extent of steering auxiliary force is altered according to a vibration generating mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device,
In particular, the present invention relates to a vehicle-mounted steering control device that generates an appropriate steering assist force when steering a steering wheel.

[0002]

2. Description of the Related Art Conventionally, in the field of vehicles, there is known a steering control device for improving a steering feeling by generating an appropriate steering assisting force when steering a steering wheel.
As such a steering control device, for example, JP-A-4-2436
Japanese Laid-Open Patent Publication No. 65 discloses a steering control device that fuzzy controls the steering assist force with vehicle speed, steering force, etc. as input conditions.

In this device, a fuzzy rule is defined for the purpose of always obtaining an optimum steering assist force when the tire characteristics and the road surface condition change. Therefore, according to the device disclosed in the above publication, it is possible to obtain an optimal steering feeling according to the traveling state under all traveling states.

[0004]

By the way, the above-mentioned conventional steering control device uses hydraulic pressure as a power source of the steering assist force. Therefore, this device is provided with a control valve that controls the hydraulic pressure in conjunction with the steering wheel, and a power cylinder that converts the hydraulic pressure controlled by the control valve into thrust in the steering direction and transmits the thrust to the rack bar, as components. There is.

In such a structure, for example, when the steering wheel is steered or turned back, self-excited vibration may occur in the control valve due to the flow of the oil liquid. Although this vibration does not cause any problem in terms of function, it causes an abnormal noise in the steering control device.

Further, to the rack bar connected to the power piston, steering force is transmitted from the steering wheel and the power piston, and at the same time traveling vibration is transmitted from the wheel side. Therefore, when a large vibration is repeatedly input to the wheels during traveling, the vibration may cause an abnormal noise from the periphery of the rack bar.

Since these abnormal noises are caused by the vibration of the control valve for controlling the hydraulic pressure which is the power source of the steering assist force or the vibration of the rack bar connected to the power piston, the control valve and the rack bar are vibrated. If the steering assist force is controlled so that a state that is unlikely to occur is formed, it can be effectively suppressed.

However, in the above-described conventional steering control device, no consideration has been given to suppressing such abnormal noise. In this sense, the above-mentioned conventional steering control device cannot always realize an ideal steering feeling from a comprehensive viewpoint including hearing.

The present invention has been made in view of the above points, and controls the steering assist force so as to suppress the vibration of the control valve or the rack bar to appropriately suppress the generation of abnormal noise. An object is to provide a steering control device.

[0010]

The above-mentioned object is defined in claim 1.
The gear vibration detection means for detecting the vibration generated in the steering gear portion, the vibration mode specifying means for specifying the vibration generation mode when the vibration occurs in the steering gear portion, and And a steering assist force varying unit that changes the steering assist force according to the vibration generation mode so that the vibration is suppressed.

Further, as described in claim 2, the above object is defined in the steering control device according to claim 1 for the purpose of suppressing the vibration generated in the steering gear portion by the steering assist force varying means. This is also achieved by a steering control device that changes the steering assist force according to a fuzzy rule in which a characteristic value relating to the intensity of the vibration is an input condition.

Further, as described in claim 3, in the steering control device according to claim 1, the steering assist force varying means is capable of both suppressing vibration generated in the steering gear portion and realizing a good steering feeling. The steering control device that changes the steering assist force according to a fuzzy rule that is specified for the purpose of using the characteristic value related to the strength of vibration and the characteristic value related to the steering feeling as input conditions is used to realize a comprehensive steering feeling. Is effective in.

[0013]

According to the present invention, when vibration is generated in the steering gear portion of the steering control device, the vibration is detected by the gear vibration detecting means, and the generation mode of the vibration is specified by the vibration mode specifying means. It When the vibration generation mode is specified in this way, the measures required to suppress the vibration are specified. The steering assist force varying means is
The steering assist force is changed so that the measures specified in this way are realized. Therefore, the vibration of the steering gear is
Properly suppressed.

According to the second aspect of the invention, the steering assist force varying means changes the steering assist force according to a fuzzy rule that uses a characteristic value relating to the intensity of vibration generated in the steering gear portion as an input condition. Further, the fuzzy rule in the present invention is stipulated so as to obtain an appropriate change value for suppressing the vibration based on the characteristic value regarding the vibration intensity. For this reason, when the steering assist force is changed by the steering assist force varying means in the present invention, the vibration of the steering gear portion is efficiently suppressed under various traveling environments.

According to the third aspect of the invention, the steering assist force varying means changes the steering assist force according to a fuzzy rule that uses a characteristic value relating to the intensity of vibration generated in the steering gear portion and a characteristic value relating to the steering feeling as input conditions. Further, the fuzzy rule in the present invention is stipulated on the basis of those characteristic values so as to obtain an appropriate change value for achieving both suppression of vibration and realization of a good steering feeling. Therefore, when the steering assist force varying means of the present invention changes the steering assist force, vibration of the steering gear portion is efficiently suppressed under various traveling environments, and an appropriate steering feeling according to the traveling state is obtained. Will be realized.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall configuration diagram of a steering control device according to an embodiment of the present invention. In FIG. 1, the steering wheel 10 is fixed to the upper end of a steering shaft 12. The steering shaft 12 has a steering angle sensor 1 for detecting a steering angle θ of the steering wheel 10.
4 is incorporated. Also, the steering shaft 1
The lower end of 2 is connected to a torsion bar 18 arranged inside the control valve 16.

Inside the control valve 16, a hollow control valve shaft 20 surrounding the outer periphery of the torsion bar 18 and a valve sleeve 22 surrounding the outer periphery of the control valve shaft 20 are incorporated. The torsion bar 18 is a member having an appropriate elasticity, and its upper end portion has a control valve shaft 20.
Of the valve sleeve 22 and the lower end thereof are fixed to the valve sleeve 22, respectively. Therefore, the steering wheel 1
When 0 is steered, the valve sleeve 22 rotates with respect to the control valve shaft 20 with a delay by the twist angle generated in the torsion bar 18.

Inside the control valve 16, a pinion gear 24 that rotates together with the valve sleeve 22 is provided. A rack bar 26 is meshed with the pinion gear 24. The rack bar 26 is a member that converts the rotational torque transmitted to the pinion gear 24 into a thrust in the horizontal direction and transmits the thrust in the steering direction to the steered wheels, and is supported by the rack guide 28.

The control valve 16 is housed in the gear housing 30. In the gear housing 30, the oil liquid outflow hole 16 a of the control valve 16 and the oil liquid inflow hole 1
6b, flow passages 32, 34, 3 leading to the hydraulic pressure supply hole 16c
6 is provided. The flow passage 32 is connected to the oil pump 38.
The fluid passages 34 and 36 are communicated with the oil liquid discharge side of the oil pump 38 via the flow dividing valve 40. Therefore, during the operation of the oil pump 38, the oil liquid inflow hole 16b of the control valve 16 and the hydraulic pressure supply hole 1
The oil liquid is supplied to 6c at an appropriate pressure, and the oil liquid is recirculated from the oil liquid outflow hole 16a toward the oil pump 38.

The gear housing 30 is provided with a solenoid valve 42 as a variable throttle for controlling the electrical connection between the flow passage 36 and the flow passage 32. Therefore, if the solenoid valve 42 is in the closed state, the hydraulic pressure supply hole 16c of the control valve 16 is supplied with a hydraulic pressure of approximately the same pressure as that supplied to the oil liquid inflow hole 16b, while the solenoid valve 42 is When the valve is open, the hydraulic pressure reduced according to the opening is supplied.

Oil liquid outflow hole 1 of control valve 16
6a and the oil liquid inflow hole 16b are opened on the side surface of the gear housing 30. Here, as shown in FIG. 2 (corresponding to the II-II section shown in FIG. 1), the control valve 16 is provided with oil passages 16d and 16e communicating with the hydraulic chambers 44a and 44b of the power cylinder 44. Further, when the control valve shaft 20 and the valve sleeve 22 described above rotate relative to each other, the oil liquid flowing from the oil liquid inflow hole 16b is discharged depending on the direction and size of the relative angle. A valve mechanism that supplies oil to one of the oil passages 16d and 16e and causes the oil liquid in the other oil passage 16d and 16e to flow out to the oil liquid outflow hole 16a is configured. Therefore, when an appropriate relative displacement occurs between the control valve shaft 20 and the valve sleeve 22 during the operation of the oil pump 38, the hydraulic pressure of any one of the power cylinders 44 is changed depending on the direction and the magnitude of the relative displacement. The oil liquid is supplied to the chambers 44a and 44b, and the oil liquid flows out from the other hydraulic chambers 44a and 44b.

Further, as shown in FIG. 3 (corresponding to the III-III section shown in FIG. 1), the control valve 16 is provided with a hydraulic reaction force chamber 16f communicating with the hydraulic pressure supply hole 16c. Inside the hydraulic reaction force chamber 16f, a plunger 46a for sandwiching the control valve shaft 20 at two places.
46d is provided. These plungers 46a-
46d is a member incorporated in the pinion gear 24, and is configured to generate a clamping force according to the hydraulic pressure of the hydraulic reaction force chamber 16f. According to this configuration, the greater the clamping force generated by the plungers 46a to 46d, the less likely the relative displacement between the valve sleeve 22 and the control valve shaft 20 occurs. Therefore, according to the control valve 16, the magnitude of the relative displacement generated between the control valve shaft 20 and the valve sleeve 22 when the steering wheel 10 is steered is adjusted by adjusting the hydraulic pressure supplied to the hydraulic pressure supply hole 16c. , Can be controlled.

The above-mentioned control valve 16, oil pump 38, and power cylinder 44 can be represented as shown in FIG. 4 by focusing on their functions. That is, the control valve shaft 20 and the valve sleeve 22 described above can be represented by using four diaphragms X, X ', Y, Y'as shown in the inside of the one-dot chain line in FIG. However, these throttles are variable throttles that change the pipe diameter in accordance with the relative displacement between the control valve shaft 20 and the valve sleeve 22, and when relative displacement occurs in one direction, If the diaphragms X and Y are expanded and the diaphragms X ′ and Y ′ are contracted in accordance with the magnitude of the relative displacement, while the relative displacements occur in the other directions, the diaphragms are adjusted according to the magnitude of the relative displacement. The apertures X ′ and Y ′ are enlarged and the apertures X and Y are reduced.

According to this structure, when no steering torque is applied to the steering shaft 12 and no relative displacement occurs between the control valve shaft 20 and the valve sleeve 22, the power cylinder 44
The hydraulic pressure generated in the hydraulic chambers 44a and 44b becomes equal pressure. Therefore, in that case, the oil pump 38 and the power cylinder 4
The oil liquid is not exchanged with the oil pump 4, and all the oil liquid discharged from the oil pump 38 is returned to the reservoir tank of the oil pump 38 through the inside of the control valve 16.

On the other hand, the steering shaft 12
When a steering torque is applied to the control valve shaft 20 and a relative displacement occurs between the control valve shaft 20 and the valve sleeve 22 in accordance with the magnitude of the steering torque, the oil passages 16d and 16e.
There is a pressure difference between and. In this case, the pressure difference is guided to the power cylinder 44, and horizontal thrust is generated by the power cylinder 44 until the relative displacement between the control valve shaft 20 and the valve sleeve 22 is achieved.

By the way, the power cylinders 44 are provided in series in the axial direction of the rack bar 26 shown in FIG.
Therefore, the horizontal thrust generated in the power cylinder 44 is a force that displaces the rack bar 26 in the steering direction.
That is, it acts as a steering assist force. In the steering control device of this embodiment, the steering assist force when the steering wheel 10 is steered is generated in this way.

Further, in the steering control system of this embodiment, as described above, the hydraulic pressure of the hydraulic reaction chamber 16f can be adjusted by adjusting the opening state of the solenoid valve 42. Further, by adjusting the hydraulic pressure in the hydraulic reaction chamber 16f, the magnitude of the relative displacement generated between the control valve shaft 20 and the valve sleeve 22 with respect to the steering torque applied to the steering wheel 10 can be appropriately adjusted. Can be controlled.

Therefore, according to the steering control device of the present embodiment, the larger the opening of the solenoid valve 42 and the lower the hydraulic pressure in the hydraulic reaction chamber 16f, the greater the steering assist force with a small steering torque. The hydraulic reaction force chamber 16 can be obtained by reducing the opening degree of the solenoid valve 42.
As the hydraulic pressure in f is increased, the feeling of rigidity during steering can be increased.

As shown in FIG. 1, the solenoid valve 42 described above is a power steering computer (hereinafter,
It is controlled by 48). In addition to the steering angle sensor 14 described above, the ECU 48 includes a vertical G sensor 50 that detects vertical vibrations that occur in the control valve 16 and the gear housing 30 (hereinafter collectively referred to as PS gear 49), and a vertical direction of the right front wheel. The right front wheel up / down G sensor 52 for detecting vibration, the left rear wheel up / down G sensor 54 for detecting up / down G of the left rear wheel, the engine speed sensor 56 for detecting engine speed, and the oil liquid flowing in the steering control device ( Less than,
An oil temperature sensor 58 incorporated in the oil pump 38 for detecting the temperature of PS oil (hereinafter referred to as PS oil temperature) and a vehicle speed sensor 60 for detecting the vehicle speed are connected.

By the way, in the steering control device, a control is widely performed in which a large steering assist force is generated during low speed traveling and the steering assist force is attenuated as the vehicle speed increases. It is necessary to generate a large steering assist force in order to obtain a light steering operability during low-speed traveling, while the steering assist force must be small in order to obtain a stable steering feeling during high-speed traveling. This is because it is preferable.

In the configuration of the steering control device of this embodiment, such a function can be realized by reducing the opening degree of the solenoid valve 42 as the vehicle speed increases. Therefore, if only the steering operability is set, the steering assist force is determined as a function of the vehicle speed, and the solenoid valve 42 is controlled so as to realize the steering assist force. be able to.

On the other hand, in the steering control device,
Noise may occur due to the self-excited vibration of the control valve 16 accompanying the flow of PS oil or the vibration of the rack bar 26 due to the traveling vibration. It is not sufficient to simply control the steering assist force as a function of the vehicle speed in order to suppress and realize the optimum steering feeling in a comprehensive sense including the sense of hearing. The steering control device of the present embodiment is E
From this point of view, the CU 48 is characterized by executing steering assist force control for the purpose of suppressing abnormal noise. Less than,
The contents of the characteristic processing executed by the ECU 48 will be described with reference to FIGS.

FIG. 5 shows the tendency of self-excited vibration occurring in the control valve 16 due to the PS oil flowing inside the control valve 16, showing the magnitude of the hydraulic reaction force, that is, the inside of the hydraulic reaction force chamber 16f. The characteristic diagram expressed in relation to the magnitude of the hydraulic pressure is shown. The self-excited vibration of the control valve 16 occurs, for example, when the steering wheel 10 is steered steeply, when the steering wheel 10 is suddenly turned back, or the like. Is less likely to occur, and a large force is obtained as the supporting force of the control valve shaft 20,
For this reason, the self-excited vibration is unlikely to occur in the control valve 16. Therefore, when the vibration estimated to be the self-excited vibration of the control valve 16 is detected while the vehicle is traveling,
By taking measures to increase the hydraulic pressure in the hydraulic reaction force chamber 16f, it is possible to suppress abnormal noise (hereinafter, this abnormal noise is artificially referred to as "gear goo") due to the vibration.

In the steering control device, when the rack bar 26 vibrates due to transmission of traveling vibration, the rack bar 26 and the rack guide 28 collide with each other, which may cause abnormal noise ( In the following, this abnormal sound is artificially referred to as a "slow sound". Here, FIG. 6 is a characteristic diagram showing the tendency of vibration generated in the rack bar 26 during traveling of the vehicle in relation to the magnitude of the hydraulic reaction force, that is, the magnitude of the hydraulic pressure in the hydraulic reaction force chamber 16f. . As shown in FIG. 6, the vibration of the rack bar 26 is less likely to occur as the hydraulic reaction force increases. This is because as the hydraulic reaction force increases, the rigidity in the rotation direction of the pinion gear 24 that engages with the rack bar 26 improves. Therefore, if a clicking noise occurs while the vehicle is running,
If a measure to increase the hydraulic pressure in the hydraulic reaction force chamber 16f is taken, the rattling noise can be suppressed.

The above-mentioned gear goo noise is an abnormal noise that tends to occur when an attempt is made to generate a relatively large steering assist force. Therefore, the gear goo noise does not occur during high speed traveling in which the steering assist force is appropriately damped by the basic control of the steering control device. On the other hand, the click sound described above is generated by the rack bar 2
It does not occur unless a relatively large traveling vibration is input to 6. Therefore, a rattling noise does not occur during low-speed traveling where traveling vibration is relatively small.

Therefore, in the steering control system of this embodiment, the vertical G sensor 50 arranged below the control valve 16 detects the vibration generated in the control valve 16 and the rack bar 26, and the vibration is detected. Based on the vehicle speed at the time, it is determined whether the detected vibration is the vibration that causes the gear goo noise or the vibration that causes the click noise, and the steering assist force is appropriately controlled according to each situation. I have decided.

FIG. 7 shows the ECU 4 for realizing such a function.
8 shows a flow chart of an example of a control routine executed by 8. This routine starts when the ignition switch of the vehicle is turned on. When this routine is started, first, at step 100, a process of reading various control value maps and fuzzy membership function maps (maps shown in FIGS. 8 to 16) used in the following processes is performed. The contents of each map will be described later.

After the above processing is completed, in step 102, signals output from various sensors connected to the ECU 48 are read, and in step 104, the steering speed Δθ is calculated. The steering speed Δθ is calculated by subtracting the steering angle θ _n-1 detected in the previous processing from the steering angle θ _n detected by the steering angle sensor 14 in the current processing, and taking the absolute value thereof.

When the calculation of the steering speed Δθ is completed, the routine proceeds to step 106, where it is judged based on the output signal “G gear up / down” of the up / down G sensor 50 whether the PS gear 49 has vertical vibration. This routine is a routine for suppressing abnormal noise caused by the vibration of the PS gear 49,
This is because no special measures need to be taken when the PS gear 49 does not vibrate.

Therefore, when G gear up / down> G ₀ is not satisfied with respect to G ₀ set as the threshold value, a large vibration is generated in the PS gear 49 so that an occupant of the vehicle recognizes it as an abnormal noise. If not, the process proceeds to step 108, and the control value for suppressing the gear goo noise (hereinafter referred to as the gear goo sound control value) ΔS ₁ and the control value for suppressing the click noise (hereinafter, the click noise control value). ) ΔS ₂
After substituting "0" for both, go to step 110.

In step 110, the above step 100 is performed.
Based on the map shown in FIG. 8 read in step 3, a process for reading a control output value (hereinafter, referred to as a vehicle speed control output value) S for realizing the steering assist force according to the vehicle speed is performed. The vehicle speed control output value S is a basic value of the current value supplied to the solenoid valve 42 as will be described later, and corresponds to the basic opening degree to be achieved in the solenoid valve 42. Therefore, when the vehicle speed control output value S is obtained based on the map shown in FIG. 8, the opening degree of the solenoid valve 42 is basically controlled to be large at low speed traveling and small at high speed traveling.
Therefore, according to the steering control device of the present embodiment, basically, a large steering assist force can be obtained at low speed traveling, and a small steering assist force can be obtained at high speed traveling to obtain good steering operability. It is possible to satisfy the above-mentioned characteristics required for the above.

After the above processing is completed, next step 11
Advances to 2, the vehicle speed control output S, by subtracting Giyagu sound control value [Delta] S ₁ and clattering sound control value [Delta] S ₂ described above, calculates the control signal S ₀ of the current supplied to the solenoid valve 42. As described above, when both ΔS ₁ and ΔS ₂ are “0”, the vehicle speed control output S is directly calculated as the control signal S ₀ . And the following step 114
Then, after the control signal S ₀ is output to the drive circuit of the solenoid valve 42, the processes of step 102 and thereafter are executed again.

In the steering control system of this embodiment, when the PS gear 49 is vibrated to the extent that it is recognized as an abnormal noise,
The condition of step 106 is satisfied, and then step 11
6 is executed. In step 116, the wheel speed is "0".
This is a step of determining whether the vehicle is in the vicinity, that is, whether the vehicle is traveling at high speed, traveling at low speed, or stopped. As described above, the gear goo noise is not generated during high-speed traveling, and the rattling noise is not generated during low-speed traveling or at rest. Therefore, the PS gear 49 is output to the PS gear 49 based on the output signal "V vehicle speed sensor" of the vehicle speed sensor 60. It is intended to identify the generation mode of the generated vibration.

Specifically, the value V set as the threshold value
_{On the} other hand, if V vehicle speed sensor <V ₀ is true for _0, PS
It is determined that the vibration of the gear 49 is caused by the self-excited vibration of the control valve 16, and the gear goo sound logic of step 118 and thereafter is executed. On the other hand, when V vehicle speed sensor <V ₀ is not established, it is determined that the vibration of the PS gear 49 is due to the vibration of the rack bar 26, and
Then, the sound logic of step 132 and thereafter is executed.

The gear goo sound logic is a logic for calculating the gear goo sound control value ΔS ₁ . In this logic, the higher the need to suppress the gear goo noise, the larger the value of ΔS ₁ will be. That is, in the gear goo sound logic, first, at step 118, the gear goo sound membership function Ms1 for the steering speed Δθ is obtained based on the map shown in FIG. The higher the steering speed Δθ, the more easily self-excited vibration of the control valve 16 occurs. Therefore, this map is set such that the higher Δθ, the larger the value of Ms1.

Next, at step 120, the gear goo sound membership function Mt1 with respect to the PS oil temperature is obtained based on the map shown in FIG. Gear goo noise is particularly likely to occur when the PS temperature is in a specific region due to the relationship with the viscosity of PS oil, etc. Therefore, this map is set so that Mt1 has a large value corresponding to such region. ing.

In step 122, the gear goo sound membership function Me1 with respect to the engine speed is obtained based on the map shown in FIG. When the engine speed is high, it is considered that the vehicle speed will soon increase and the gear goo noise will not occur, and because the engine noise is large and the gear goo noise will not be a problem so much, this map is prioritized for steering operability. , Me1 is set to have a relatively large value only in the low rotation region.

In step 124, the gear goo sound membership function Mg1 for the vertical acceleration of the PS gear is obtained based on the map shown in FIG. The gear goo sound generated by the vibration of the PS gear 49 becomes louder as the vibration of the PS gear 49 becomes larger. Therefore, this map is set such that the larger the vertical acceleration of the PS gear, the larger the value of Mg1.

When these processes are completed, step 126
At each gear goo sound membership function Ms1, Mt
The average value Ma1 of 1, Me1 and Mg1 is calculated. Next, at step 128, based on the map shown in FIG. 13, the gear goo sound control value ΔS corresponding to the average value Ma1.
Read ₁ Then, in step 130, “0” is substituted for the click sound control value ΔS _2, and the process proceeds to step 110.

In this case, thereafter, in step 112, the control signal S ₀ is a value obtained by subtracting ΔS ₁ set in accordance with the state of occurrence of gear goo noise from the vehicle speed control output value S. Therefore, as the gear goo noise is more likely to be generated, the current supplied to the solenoid valve 42 becomes smaller and the hydraulic reaction force of the control valve 16 is increased. Therefore, according to the steering control device of the present embodiment, the gear goo noise generated in the PS gear 49 can be appropriately suppressed while appropriately changing the steering assist force according to the vehicle speed.

By the way, in the above steps 126 and 128, the gear goo tone membership functions Ms1, Mt1, and Me.
1, as an example of fuzzy control using Mg1, the gear goo sound control value ΔS ₁ is obtained from the average value thereof, but the method of obtaining ΔS ₁ is not limited to this.
For example, a method of obtaining ΔS ₁ based on the maximum values of Ms1, Mt1, Me1, and Mg1 can be used.

The click sound logic is a logic for calculating the click control value ΔS ₂ . In this logic, the higher the need to suppress the click sound, the larger the value of ΔS ₂ will be given. That is, in the click sound logic, first, at step 132, the click sound membership function Ms2 for the steering speed Δθ is obtained based on the map shown in FIG. The region where the steering speed Δθ is high is a region where a large steering force is applied to the rack bar 26, and vibration is unlikely to occur in the rack bar 26, and when high-speed Δθ occurs during high-speed traveling, it is difficult. For the reason that the steering operability should be prioritized over the suppression of sound, this map shows that Ms is set when Δθ is low.
2 is set to be a relatively large value.

Next, at step 134, a click sound membership function Mv2 for the vehicle speed v is obtained based on the map shown in FIG. The click sound is the rack bar 26
Since the stronger the vibration intensity transmitted to the vehicle is, that is, the greater the intensity of the traveling vibration is, the more likely it is to occur, the map is set so that Mv2 has a large value in the high speed region where the intensity of the traveling vibration is large.

In step 136, a click sound membership function Me2 for the engine speed is obtained based on the map shown in FIG. When the engine speed is high, the engine sound is loud and the rattling sound is not a serious problem. Therefore, in order to prioritize the steering operability, this map has a relatively large value of Me2 only in the low speed region. It is set.

In step 138, a click sound membership function Mg2 for the vertical acceleration of the PS gear is obtained based on the map shown in FIG. Since the rattling sound generated by the vibration of the PS gear 49 becomes louder as the vibration of the PS gear 49 becomes larger, this map is set so that the larger the vertical acceleration of the PS gear becomes, the larger the value of Mg2 becomes. It should be noted that this map and the map shown in FIG. 12 used in the gear goo sound logic can be shared.

When these processes are completed, step 140
At each tone sound membership function Ms2, Mv
The average value Ma2 of 2, Me2 and Mg2 is calculated. Next, at step 142, based on the map shown in FIG. 18, the click sound control value ΔS corresponding to the average value Ma2.
Read ₂ Then, in step 144, “0” is substituted for the gear goo sound control value ΔS _1, and the process proceeds to step 110.

In this case, in step 112, the control signal S ₀ is a value obtained by subtracting ΔS ₂ which is set according to the occurrence of the rattling sound from the vehicle speed control output value S. Therefore, the current supplied to the solenoid valve 42 becomes smaller and the hydraulic reaction force of the control valve 16 is increased as the rattling noise easily occurs. Therefore, according to the steering control device of the present embodiment, it is possible to appropriately suppress the rattling sound generated in the PS gear 49 while appropriately changing the steering assist force according to the vehicle speed.

By the way, in the above steps 140 and 142, the click tone membership functions Ms2, Mv2, Me.
2, as an example of fuzzy control using Mg2, the sound control value ΔS ₂ is determined from the average value thereof, but the method of determining ΔS ₂ is not limited to this.
For example, it is possible to use a method of obtaining ΔS ₂ based on the maximum values of Ms2, Mv2, Me2 and Mg2.

In the above embodiment, the PS gear 49
Corresponds to the steering gear portion described above. In addition, the ECU 4
8 executes the process of step 106,
The above-mentioned gear vibration detection means executes the processing of the above step 116 so that the above-mentioned vibration mode identification means performs the above steps 110 to 114 and step 118.
By executing steps 144 to 144, the steering assist force varying means described above is realized.

Further, in the above embodiment, the steering speed Δθ in the gear goo sound logic, the PS oil temperature, the PS gear vertical acceleration, and the steering speed Δ in the click sound logic.
θ, vehicle speed v, PS gear vertical acceleration, etc. correspond to the above-mentioned characteristic values relating to the intensity of vibration, and the vehicle speed control output value S
The vehicle speed v, the engine speed in the gear goo sound logic, and the steering speed Δθ, the engine speed, and the like in the sound sound logic, which are the basis of the above, correspond to the characteristic values relating to the steering feeling described above.

By the way, the control routine shown in FIG. 7 is based on the achievement of the steering assist force according to the vehicle speed, and is corrected mainly for suppressing abnormal noises such as gear goo noise and rattling noise. It is a routine. On the other hand, when the steering operability is emphasized, it is necessary to perform the correction for suppressing the abnormal noise within the range where the steering operability is not affected. Hereinafter, with reference to FIGS. 19 to 31,
From this viewpoint, the content of the processing executed by the ECU 48 will be described.

FIG. 19 shows a flowchart of an example of a control routine executed by the ECU 48 from the above viewpoint.
In the figure, the same steps as those shown in FIG. 7 are designated by the same reference numerals, and the description thereof will be simplified or omitted. The routine shown in FIG. 19 starts when the ignition switch of the vehicle is turned on. When this routine starts, first in step 200,
A process of reading various control value maps and fuzzy membership function maps (maps shown in FIGS. 20 to 31) used in the following process is performed. The contents of each map will be described later.

After the above processing is completed, signals output from various sensors connected to the ECU 48 are read in step 102, the steering speed Δθ is calculated in step 104, and it is determined in step 116 whether the vehicle speed is low. . As a result, when V vehicle speed sensor <V ₀ is established,
It is determined that the rattling noise does not occur, and the gear goo tone logic after step 202 is executed. On the other hand, when the V vehicle speed sensor <V ₀ is not established, it is determined that the gear goo noise does not occur, and the spilling sound logic after step 224 is executed.

The gear goo sound logic in this routine has a gear goo sound control value ΔS ₁ and a control correction value ΔS ₂ for reducing deterioration of steering operability associated with suppression of the gear goo sound.
Is a logic for calculating In the present logic, the greater the need to suppress the gear goo noise, the larger the value assigned to ΔS _1, and the greater the need to maintain high steering operability, the greater the value assigned to ΔS ₂ .

As shown in FIG. 19, in the gear goo sound logic, first, at step 202, the steering speed correction value Kθ corresponding to the steering speed Δθ is read based on the map shown in FIG. The steering speed correction value Kθ is a coefficient that is introduced in order to accurately grasp the generation condition of the gear goo noise, and this map shows that the higher the steering speed Δθ, that is, the easier the gear goo noise is generated, the more the Kθ becomes. It is set to a large value.

Next, at step 204, the vertical G sensor 5
The gear goo sound determination function “J goo sound” is calculated by multiplying the steering speed correction value Kθ obtained as described above by “G gear up / down” which is an output signal of 0. This “J goo sound” is a function that has a larger value as the loud gear goo sound is generated in the PS gear 49 and the gear goo sound is more likely to be generated. Therefore, the larger the value, the higher the need to suppress the gear goo noise.

At step 206, it is judged whether or not "J goo sound" is smaller than "J goo sound ₀ " set as a threshold value. As a result, when the condition of "J goo sound <J goo sound ₀ " is not satisfied, it is necessary to suppress the gear goo sound, and the processing from step 208 onward is executed.

In step 208, the gear goo noise control value ΔS ₁ for the vertical acceleration of the PS gear is obtained based on the map shown in FIG. The gear goo sound generated by the vibration of the PS gear 49 becomes louder as the vibration of the PS gear 49 becomes larger. Therefore, this map is set so that ΔS ₁ becomes larger as the vertical acceleration of the PS gear becomes larger.

Steps 210 to 218 are steps for obtaining the control correction value ΔS ₂ used for correcting ΔS ₁ according to the fuzzy rule. That is, in step 210, the gear goo sound membership function Ms3 for the steering speed Δθ is obtained based on the map shown in FIG. The steering speed Δθ becomes high when it is necessary to steer the steering wheel 10 rapidly, and it is appropriate to give priority to ensuring steering operability with respect to suppressing gear goo noise.
Therefore, this map is set so that Ms3 has a larger value as Δθ becomes faster.

Next, at step 212, the gear goo sound membership function Mt3 with respect to the PS oil temperature is obtained based on the map shown in FIG. The gear goo noise is unlikely to occur when the PS temperature is out of a specific temperature range due to the relationship with the viscosity of PS oil, etc. Therefore, in such a region, it is necessary to secure steering operability for suppressing the goo go sound. It is appropriate to give priority. Therefore, this map is set such that Mt3 has a large value in the low temperature region and the high temperature region of the PS temperature.

In step 214, the gear goo sound membership function Me3 with respect to the engine speed is obtained based on the map shown in FIG. When the engine speed is high, it is considered that the vehicle speed will soon increase and the gear goo noise will not occur, and the engine goo noise will be large and the gear goo noise will not be a serious problem. Therefore, in the region where the engine speed is high, it is appropriate to secure the steering operability with respect to the suppression of gear goo noise. Therefore, this map is set such that Me3 has a large value in a region where the engine speed is high.

At step 216, the maximum value Mmax3 of each gear goo sound membership function Ms3, Mt3, Me3 is obtained. Next, at step 218, the control correction value ΔS ₂ corresponding to the maximum value Mmax3 is read out based on the map shown in FIG. Then, in step 220, “0” is substituted into the click sound control value ΔS ₃ and the control correction value ΔS ₄ for reducing the deterioration of the steering operability accompanying the suppression of the click sound, and the routine proceeds to step 110.

In this routine, step 110 is executed.
After obtaining the vehicle speed control output value S in advance (see the above-mentioned FIG. 8).
), In step 222, S₀= S- (ΔS₁−
ΔS ₂+ ΔS₃-ΔS_Four) Control signal according to
S₀, The S₀Of the solenoid valve 42
Control is performed (step 114).

When the gear goo tone logic described above is executed, the control signal S ₀ becomes S ₀ = S- (ΔS ₁ -ΔS ₂ ). In this case, the control signal S ₀ includes a tendency for obtaining an appropriate steering assist force according to the vehicle speed, a tendency for suppressing the generation of gear goo noise, and a decrease in steering operability associated with the suppression of gear goo noise. All the tendencies to do so are reflected appropriately. Therefore, according to the processing of this routine, it is possible to appropriately suppress the gear goo noise generated in the PS gear 49 while maintaining good steering operability.

By the way, in steps 216 and 218, gear goo tone membership functions Ms3, Mt3, Me
As an example of the fuzzy control using 3, the correction control value ΔS ₂ is determined from the maximum values thereof.
₂ of Determination is not limited to this, for example Ms3,
It is also possible to use a method of obtaining ΔS ₂ based on the average value of Mt3 and Me3.

The beating sound logic in this routine has a beating sound control value ΔS ₃ and a control correction value ΔS ₄ for reducing the deterioration of the steering operability accompanying the suppression of the beating sound.
Is a logic for calculating In this logic, a larger value is assigned to ΔS ₃ as the need to suppress the click sound increases, and a larger value is assigned to ΔS ₄ as the need to maintain high steering operability increases.

As shown in FIG. 19, in the gear goo sound logic, first, at step 224, the correlation coefficient R of the upper and lower G generated on the right front wheel and the left rear wheel is calculated. The correlation coefficient R is a coefficient representing the magnitude of traveling vibration transmitted to the vehicle body as the vehicle travels, and the right front wheel vertical G sensor 5
2. Calculated based on the output signal of the left rear wheel up / down G sensor 54.

Next, at step 226, the wheel vertical G correlation correction value K _R corresponding to the correlation coefficient _R is read based on the map shown in FIG. Wheel up / down G correlation correction value K _R
Is a coefficient that is introduced in order to accurately grasp the occurrence of the click sound, and in this map, the larger the value of the correlation coefficient R, that is, the larger the vibration of the vehicle body itself, the smaller the value of K _R is. Is set to.

Next, at step 228, the vertical G sensor 5
By multiplying "G gear up and down", which is an output signal of 0, and K _R obtained as described above, a squeaky sound determination function "J squeaky sound" is calculated. This "J sound"
Is a function that takes a larger value as the component of the vibration generated in the PS gear 49 that differs from the vibration of the vehicle body increases. Therefore, the larger the value, the higher the need to suppress the clicking sound.

At step 230, "J click sound"
Is smaller than the "J-beat sound ₀ " set as the threshold value. As a result, "J click sound <J
If the condition of "clicking sound ₀ " is not satisfied, it means that the clicking sound needs to be suppressed.
The processing after 32 is executed.

In step 232, the click sound control value ΔS ₃ for the vertical acceleration of the PS gear is obtained based on the map shown in FIG. The gear goo sound generated by the vibration of the PS gear 49 becomes louder as the vibration of the PS gear 49 becomes larger. Therefore, this map is set so that ΔS ₃ has a larger value as the vertical acceleration of the PS gear becomes larger.

Steps 234 to 242 are steps for obtaining the control correction value ΔS ₄ used for correcting ΔS ₃ according to the fuzzy rule. That is, in step 234, the click sound membership function Ms4 for the steering speed Δθ is obtained based on the map shown in FIG. When a high steering speed Δθ is generated during high-speed traveling, it is important to ensure steering operability, so this map is
It is set so that Ms4 has a larger value as θ becomes faster.

Next, at step 236, the click sound membership function Mθ4 for the steering angle θ is obtained based on the map shown in FIG. In the area where the steering angle θ is large,
It is appropriate to give a high sense of rigidity because there is little further steering, and on the other hand, in a region where the steering angle θ is small, a large amount of steering is often performed to give a light steering feel. Is appropriate. For this reason,
This map is set so that Mθ4 is relatively large in a region where θ is small and Mθ4 is relatively small in a region where θ is large.

In step 238, the click sound membership function Me4 with respect to the engine speed is obtained based on the map shown in FIG. When the engine speed is high, the engine sound is large and the click noise is not a serious problem. Therefore, it is appropriate to secure the steering operability to suppress the click noise. Therefore, this map is
Me4 is set to have a large value in a region where the engine speed is high.

In step 240, the maximum value Mmax4 of each of the click sound membership functions Ms4, Mθ4, Me4 is obtained. Next, at step 242, the control correction value ΔS ₄ corresponding to the maximum value Mmax4 is read out based on the map shown in FIG. Then, in step 244, "0" is assigned to the gear goo noise control value ΔS ₁ and the control correction value ΔS ₂ for reducing the deterioration of the steering operability accompanying the suppression of the gear goo noise, and the routine proceeds to step 110 described above. .

In this case, in step 222, S ₀ = S
The control signal S ₀ according to the arithmetic expression − (ΔS ₃ −ΔS ₄ ).
Is calculated, and the control of the solenoid valve 42 is executed by S ₀ . S calculated as above
_{At 0,} there is a tendency for obtaining an appropriate steering assist force according to the vehicle speed, a tendency for suppressing the generation of a rattling sound, and a tendency for preventing the deterioration of the steering operability accompanying the suppression of the rattling sound. All are reflected appropriately. Therefore, according to the processing of this routine, it is possible to appropriately suppress the rattling noise generated in the PS gear 49 while maintaining good steering operability.

By the way, in the above steps 240 and 242, the click tone membership functions Ms4, Mθ4, Me.
As an example of fuzzy control using 4, the correction control value ΔS ₄ is determined from those maximum values.
The method of obtaining ₄ is not limited to this. For example, Ms4
It is also possible to use a method of obtaining ΔS ₄ based on the average value of Mθ4 and Me4.

[0088] Furthermore, in this routine, the condition when the condition of "J goo sound <J Goo sound _0" in step 206 is determined to be satisfied, and "J clattering sounds <J clattering sounds _0" in step 230 If it is determined that the above condition is satisfied, it can be determined that the PS gear 49 does not generate vibration that is large enough to be recognized as an abnormal noise. Therefore, in such a case, it is not necessary to execute the processing for suppressing the gear goo noise and the click noise. Therefore, when the above condition is satisfied, after substituting “0” into ΔS _{1 to} ΔS ₄ in step 246,
Go to step 110. Therefore, according to this routine, ideal steering operability that changes according to the vehicle speed can be obtained when the vibration to be suppressed does not occur in the PS gear 49.

In the above embodiment, the ECU 48 executes the processing in steps 202 to 206 and 224 to 228, and the gear vibration detecting means executes the processing in step 116.
The above-mentioned vibration mode specifying means uses the above step 110,
By executing Step 114, Steps 208 to 222, and Steps 232 to 244, the steering assist force varying means described above is realized.

Further, in the above embodiment, the gear vertical acceleration in the gear goo sound logic and the click sound sound logic corresponds to the above-mentioned characteristic value relating to the intensity of vibration,
Further, the vehicle speed v that is the basis of the vehicle speed control output value S, the steering speed Δθ in the gear goo sound logic, the PS oil temperature, the engine speed, and the steering speed Δ in the click sound logic.
θ, the steering angle θ, the engine speed, and the like correspond to the above-mentioned characteristic values regarding the steering feeling.

By the way, in the steering control device shown in FIG. 1, the hydraulic reaction chamber 16f is provided inside the control valve 16.
Is provided, and a hydraulic reaction force type steering control device that changes the magnitude of the steering assist force by adjusting the hydraulic pressure supplied to the inside. On the other hand, as the configuration of the steering control device,
A diversion control type configuration is known in which the steering assist force is variable by varying the amount of PS oil flowing through the inside of the control valve 16. The steering control device for such a flow control spine can be represented as shown in FIG. 32, focusing on the function of each component. In the figure, the same reference numerals as those of the constituent elements shown in FIG. 4 are given to the respective constituent elements.

According to the configuration shown in FIG. 32, the oil liquid inflow hole 1
The amount of PS oil flowing into the control valve 16 from 6b changes according to the opening degree of the solenoid valve 42,
The smaller the opening of the solenoid valve 42, the more PS
The oil will be used as a power source for the steering assist force.

As described above, the steering assist force is balanced between the throttles X and X ′ and the throttle Y when a relative displacement occurs between the control valve shaft 20 and the valve sleeve 22.
And Y ′ are out of balance and PS oil flows into one of the hydraulic chambers 44a and 44b of the power cylinder 44.

Therefore, in the flow rate control type steering control device shown in FIG. 32, the larger the PS oil flowing through the inside of the control valve 16, the larger the steering assist force with respect to the slight steering force. Become. For this reason,
According to the configuration shown in the figure, a large steering assist force can be secured by reducing the opening degree of the solenoid valve 42, and a high rigidity feeling can be obtained by increasing the opening degree of the solenoid valve 42. Obtainable.

The gear goo noise generated in the PS gear 49 is caused by the self-excited vibration of the control valve 16 when the PS oil flows as described above. As shown in FIG. 33, this self-excited vibration is more likely to occur as the flow rate of PS oil flowing through the control valve 16 (hereinafter referred to as the effective flow rate) increases. Therefore, in the flow rate control type steering control device, the gear goo noise can be suppressed by reducing the effective flow rate, that is, by increasing the opening degree of the solenoid valve 42.

The rattling noise generated in the PS gear 49 is generated due to the collision between the rack bar 26 and the rack guide 28 as described above. Rack bar 26
Is more difficult to occur as the supporting rigidity of the rack bar 26 by the master cylinder 44 is higher. Also, the master cylinder 4
The supporting rigidity of the rack bar 26 by 4 becomes higher as the effective flow rate increases. Therefore, the vibration of the rack bar 26 becomes less likely to occur as the effective flow rate increases, as shown in FIG. Therefore, in the flow rate control type steering control device, the rattling noise can be suppressed by increasing the effective flow rate, that is, by reducing the opening degree of the solenoid valve 42.

Therefore, in the control routine shown in FIG. 7, the vehicle speed control output S corresponding to the characteristics of the flow rate control type steering control device is obtained in step 110, and step 1
If the control signal S ₀ is calculated according to the calculation formula S ₀ = S + ΔS ₁ −ΔS _{2 in} 12, the ECU 48 executes the same routine, so that the gear goo sound and the gear goo sound are appropriately generated even in the flow rate control type steering control device. The click sound can be suppressed.

Similarly, in the control routine shown in FIG. 19, the vehicle speed control output S corresponding to the characteristics of the flow rate control type steering control device is obtained in step 110, and S ₀ = S + (ΔS in step 222. _1- ΔS ₂ -ΔS ₃ + Δ
If the control signal S ₀ is calculated according to the calculation formula S ₄ ), the ECU 48 executes the same routine so that the gear goo noise and the rattling noise can be suppressed appropriately even in the flow rate control type steering control device. You can

[0099]

As described above, according to the first aspect of the present invention, when the steering gear portion vibrates, the steering assist force is changed in accordance with the vibration generation mode, and the vibration is appropriately changed. Is suppressed. Therefore, according to the steering control device of the present invention, it is possible to effectively prevent a large noise from being generated from the steering gear portion.

According to the second aspect of the present invention, the steering assist force is changed in accordance with the fuzzy rule defined for the purpose of suppressing the vibration generated in the steering gear portion. Therefore, according to the steering control device of the present invention, it is possible to appropriately suppress the vibration of the steering gear portion under various traveling environments.

Further, according to the third aspect of the invention, according to the fuzzy rule defined for the purpose of both suppressing vibration generated in the steering gear portion and realizing an appropriate steering feeling according to the running state of the vehicle, The steering assist force is changed. Therefore, according to the steering control device of the present invention, it is possible to appropriately suppress the vibration of the steering gear portion and realize an appropriate steering feeling under various traveling environments. In this sense, the steering control device of the present invention has a feature that it is possible to realize a comprehensively excellent steering sensation including an auditory sense under all traveling environments.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a hydraulic reaction force type steering control device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a valve mechanism portion of a control valve of the steering control device according to the present embodiment.

FIG. 3 is a cross-sectional view of a hydraulic reaction force chamber portion of a control valve of the steering control device according to this embodiment.

FIG. 4 is a configuration diagram functionally showing the steering control device of the present embodiment.

FIG. 5 is a characteristic diagram showing a relationship between a self-excited vibration generated in a control valve and a hydraulic reaction force in a hydraulic reaction force type steering control device.

FIG. 6 is a characteristic diagram showing a relationship between a vibration generated in a rack bar and a hydraulic reaction force in a hydraulic reaction force type steering control device.

FIG. 7 is a flowchart of a first control routine executed in this embodiment.

FIG. 8 is a map relating to vehicle speed control output values used in first and second control routines.

FIG. 9 is a map relating to a gear goo sound membership function with respect to a steering speed used in a first control routine.

FIG. 10 is a map relating to a gear goo sound membership function with respect to the PS oil temperature used in the first control routine.

FIG. 11 is a map relating to a gear goo sound membership function with respect to an engine speed used in the first control routine.

FIG. 12 is a map relating to a gear goo sound membership function with respect to PS gear vertical acceleration used in the first control routine.

FIG. 13 is a map relating to a gear goo noise control value used in the first control routine.

FIG. 14 is a map relating to a click sound membership function with respect to a steering speed used in a first control routine.

FIG. 15 is a map relating to a click sound membership function with respect to a vehicle speed used in a first control routine.

FIG. 16 is a map relating to a click sound membership function with respect to an engine speed used in a first control routine.

FIG. 17 is a map relating to a click sound membership function with respect to the vertical acceleration of the PS gear used in the first control routine.

FIG. 18 is a map relating to a click sound control value used in a first control routine.

FIG. 19 is a flowchart of a second control routine executed in this embodiment.

FIG. 20 is a map relating to a steering speed correction value used in a second control routine.

FIG. 21 is a map relating to a gear goof sound control value used in a second control routine.

FIG. 22 is a map relating to a gear goo sound membership function with respect to a steering speed used in a second control routine.

FIG. 23 is a map relating to a gear goo sound membership function with respect to the PS oil temperature used in the second control routine.

FIG. 24 is a map relating to the gear goo sound membership function with respect to the engine speed used in the second control routine.

FIG. 25 is a map relating to a gear goo noise control correction value used in the second control routine.

FIG. 26 is a map relating to a wheel vertical G correlation correction value used in a second control routine.

FIG. 27 is a map relating to a click sound control value used in a second control routine.

FIG. 28 is a map relating to a click sound membership function with respect to a steering speed used in a second control routine.

FIG. 29 is a map relating to a click sound membership function with respect to a steering angle used in a second control routine.

FIG. 30 is a map relating to a click sound membership function with respect to an engine speed used in a second control routine.

FIG. 31 is a map relating to a click sound control correction value used in a second control routine.

FIG. 32 is a functional block diagram of a flow rate control type steering control device according to a second embodiment of the present invention.

FIG. 33 is a characteristic diagram showing a relationship between a self-excited vibration generated in a control valve and an effective flow rate used as a power source of a steering assist force in a flow rate control type steering control device.

FIG. 34 is a characteristic diagram showing the relationship between the vibration generated in the rack bar and the effective flow rate used as the power source of the steering assist force in the flow rate control type steering control device.

[Explanation of symbols]

 10 Steering Wheel 14 Steering Angle Sensor 16 Control Valve 16a Oil Liquid Outflow Hole 16b Oil Liquid Inflow Hole 16c Hydraulic Pressure Supply Hole 16d, 16e Oil Path 16f Hydraulic Reaction Force Chamber 18 Torsion Bar 20 Control Valve Shaft 22 Valve Sleeve 24 Pinion Gear 26 Rack Bar 42 Solenoid valve 44 Power solenoid 48 Power steering computer (ECU) 50 Vertical G sensor 52 Right front wheel vertical G sensor 54 Left rear wheel vertical G sensor 56 Engine speed sensor 58 Engine speed sensor 60 Vehicle speed sensor

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area B62D 127: 00

Claims (3)

[Claims] 1. A gear vibration detecting means for detecting a vibration generated in a steering gear part, a vibration mode specifying means for specifying a generation mode of the vibration when the steering gear part is generated, and a vibration mode specifying means for generating a vibration in the steering gear part. The steering control device comprises: steering assist force varying means for changing the steering assist force according to the mode of occurrence of the vibration so that the vibration is suppressed. 2. The steering control device according to claim 1, wherein the steering assist force varying means is defined for the purpose of suppressing vibration generated in the steering gear portion, and fuzzy using a characteristic value relating to the strength of the vibration as an input condition. A steering control device characterized by changing a steering assist force according to a rule. 3. The steering control device according to claim 1, wherein the steering assist force varying means is defined for the purpose of both suppressing vibration generated in the steering gear portion and realizing a good steering feeling, and A steering control device characterized in that a steering assist force is changed according to a fuzzy rule in which a characteristic value relating to strength and a characteristic value relating to steering feeling are input conditions.