JP3203725B2 - Vehicle steering system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering apparatus for a vehicle, which is applied to the steered wheels of a vehicle and turns the steered wheels in response to a steering input from a driver.

[0002]

2. Description of the Related Art Conventionally, as a vehicle steering apparatus, for example, as shown in FIG. 19, a steering wheel is used as a steering input means from a driver, and a steering mechanism (a rack and pinion mechanism or a ball An apparatus for transmitting a steering wheel to a steering wheel by transmitting the wheel to a nut mechanism or the like is generally known.

As a vehicle steering system, for example,
As shown in FIG. 20, the steering input is referred to as steer-by-wire. The steering input to the steering wheel is electrically detected, this information is processed by a controller, and a control command is output to a steering actuator to respond to the steering input. There is also known a device that steers a steered wheel.

[0004]

However, in the former conventional device, the steering input side and the steering output side are mechanically connected by a constant velocity joint or the like, and the input and output transmission characteristics are uniquely or extremely limited. The vehicle's steering characteristics cannot be changed while taking into account the driver's operation characteristics, making it impossible to optimize the vehicle's steering characteristics for all drivers with different operating abilities It is.

Further, in the latter conventional device, since the steering wheel and the steering mechanism are not mechanically linked, the system configuration is extremely complicated in order to ensure fail-safe against a controller failure or the like. Become. For example, system redundancy is required by using two or more CPUs, and the system price increases.

Incidentally, the necessity of optimizing the steering characteristics of the vehicle for every driver is as follows.

FIG. 21 shows the measurement results of the operating characteristics of the driver for each age group (20s and 80s) described in "Aging effect in manual control" of "Ergonomics 22" (published in 1986). is there. In the operating characteristics of the driver, it can be seen that in the high frequency range of 0.5 Hz or more, the phase lag occurs as the driver ages.

That is, the steering reaction speed differs depending on the age, and when pylons are arranged at equal intervals as shown in FIG. 22 and a course is formed to meander between the pylons, generally, a young driver Can easily trace the course and drive, but as shown by the solid line in FIG. 22, elderly drivers cannot pass the course well when high frequency components are required for steering. . This phenomenon corresponds to the fact that the phase is delayed by the aging of the driver in a high frequency region of 0.5 Hz or more, as shown in the operating characteristics of the driver in FIG.

[0009] However, the same can not be said for all drivers, but it can be said that this is a general tendency for persons whose motor reflexes are not quick.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. In a vehicle steering system that steers steered wheels in response to a steering input from a driver, high safety is achieved at an advantageous system cost. It is an object of the present invention to optimize the steering characteristics of a vehicle for all drivers having different operation abilities while securing the same.

[0011]

In order to solve the above-mentioned problems, in a vehicle steering system according to the present invention, a low-frequency component of a steering input is mechanically transmitted through a joint, and a high-frequency component transmitted through a joint. Means for compensating only the phase lag by electrical control.

That is, as shown in the claim correspondence diagram of FIG. 1, an upper steering shaft b connected to a steering wheel a, a lower steering shaft e connected to a steering mechanism d for turning a steered wheel c, and A joint f interposed between the upper steering shaft b and the lower steering shaft e for transmitting an input in a low frequency range from at least one of the shafts and absorbing an input in a high frequency range; and the lower steering shaft e or the steering. An auxiliary steering angle mechanism g provided in the mechanism d and capable of giving an auxiliary steering angle according to an external command; a steering frequency detecting means h for detecting a steering frequency input from the steering wheel a; When the frequency is in the high frequency range, the steering wheel a in the high frequency range
And a steering characteristic control means i for outputting to the auxiliary steering angle mechanism g a command for compensating for the phase delay of the turning of the steered wheels c in response to the steering input .

When the detected steering frequency is in a high frequency range, the steering characteristic control means i controls the steering wheel c in response to the steering input of the steering wheel a in the high frequency range.
A means for outputting a command for compensating for a decrease in gain together with the phase delay of turning of the steering wheel to the auxiliary steering angle mechanism g may be used. Also,
Power spectrum area of high frequency region at steering input
Set the phase delay compensation characteristic in the compensation characteristic setting means according to
In addition, the steering characteristic control means i is set to the detected steering frequency.
Is in the high frequency range, stearin in the high frequency range
Phase of steering of steered wheel c with respect to steering input of wheel a
The delay to the compensation characteristic set by the compensation characteristic setting means.
A command to output a command for compensating based on the
It may be a step.

[0014]

When the steering frequency input from the steering wheel a is in the low frequency range, the joint f is a means for transmitting the input in the low frequency range, so that the steering input is from the steering wheel a to the upper steering shaft b.
The signal is transmitted from the joint f to the lower steering shaft e to the steering mechanism d, and the steered wheels c are steered according to the steering input.

When the steering frequency input from the steering wheel a is in the high frequency region, the joint f is a means for absorbing the input in the high frequency region, so that the steering input is absorbed by the joint f and the lower steering shaft e
, A steering input with a significantly delayed phase is transmitted. However, when the steering frequency detected by the steering frequency detecting means h is in the high frequency range, the command for compensating for the phase lag in the high frequency range in the steering characteristic control means i is given by the auxiliary steering angle mechanism g which gives the auxiliary steering angle. Is output to Therefore, by compensating the phase lag with the compensation amount according to the driver's operation characteristic by the steering characteristic control means i, it is possible to obtain a substantially constant steering phase characteristic regardless of the variation of the driver's operation characteristic. If the desired target phase characteristic is set, the phase characteristic according to the preference can be obtained. Here, when the high frequency range the phase lag compensation in the auxiliary steering angle mechanism g, although accompanied steering discomfort is concern compensation operation, by joint f is a means for absorbing the input of the high frequency range, High frequency range compensation input from the auxiliary steering angle mechanism g is hardly transmitted to the steering wheel a via the upper steering shaft b.

When the steering characteristic control system fails and the phase delay compensation in the high frequency region is not performed, the steering wheel a and the steering mechanism d are connected to the upper steering shaft b, the joint f, and the lower steering shaft e. As the steering input is low, the normal steering is ensured if the steering input is in the low frequency range, and even if the steering input is in the high frequency range, only the phase is delayed. Is secured.

When the detected steering frequency is in the high frequency range, the steering characteristic control means i is switched to the high frequency range .
Rotation of steered wheel c with respect to steering input of steering wheel a
When the means for compensating for the decrease in gain together with the phase delay of the rudder is used, it is possible to improve both the insufficient turning of the steering wheel a and the phase delay. Also, the steering characteristic control
Step i is a case where the detected steering frequency is in a high frequency region.
When the steering wheel a is turned on in the high frequency range
The phase delay of the turning of the steered wheel c with respect to the force is added to the steering input.
Compensation according to power spectrum area of high frequency region
A method for compensating based on the compensation characteristics set by the characteristic setting means
In the case of a stage, the control system such as input and arithmetic processing is simple.
While maintaining a practical system, the driver's operating characteristics
Optimum phase characteristics can be obtained regardless of variations
You.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the configuration will be described.

FIG. 2 is an overall system diagram showing a vehicle steering system according to a first embodiment of the present invention. The upper steering shaft 3 is connected to a steering wheel 1 via a constant velocity joint 2. A lower steering shaft 5 coupled to a steering mechanism 4 for steering a steered wheel (not shown); and a lower steering shaft 5 interposed between the upper steering shaft 3 and the lower steering shaft 5 to enter a low frequency region.
A rubber coupler 6 (corresponding to a joint) that transmits a force and absorbs an input in a high frequency region, and a steering actuator 7 (an auxiliary member) that is provided on the lower steering shaft 5 and can provide an auxiliary steering angle according to an external command. A steering angle mechanism), a steering angle sensor 8 provided on the upper steering shaft 3 and detecting a steering angle of the steering wheel 1, and a rotation angle sensor provided on the lower steering shaft 5 and detecting a rotational displacement thereof. 9 and a controller 10 that receives sensor signals from the two sensors 8 and 9 and outputs a control command to the steering actuator 7.
And

As shown in FIG. 3, the rubber coupler 6 includes an input member 6a fixed to the upper steering shaft 3, an output member 6b fixed to the lower steering shaft 5, an input member 6a and an output member 6b. And a soft rubber 6c interposed therebetween.

The steering actuator 7 comprises an output gear 7a provided on the lower steering shaft 5, a DC motor 7c having an input gear 7b, and an intermediate gear 7d meshing with both gears 7a, 7b.

Next, the operation will be described.

FIG. 4 is a flowchart showing the flow of the steering characteristic control processing operation performed by the controller 10, and each step will be described below.

In step 40, the steering angle θ _IN from the steering angle sensor 8 and the rotation angle θ _OUT from the rotation angle sensor 9 are read.

In step 41, the detected steering angle θ _IN
Is differentiated to calculate a steering frequency fθ (corresponding to a steering frequency detecting means).

In step 42, it is determined whether the steering frequency fθ is equal to or higher than a set frequency fθ ₀ (for example, 0.5 Hz). When fθ <fθ _0, the process returns to step 40, and when fθ ≧ fθ ₀ , the process proceeds to the phase compensation process of step 43 and subsequent steps.

[0028] At step 43, the target phase delay P _E ^* is calculated by the steering frequency fθ and the target phase characteristic P _E ^* (f) (the broken line in FIG. 9).

In step 44, the actual phase delay amount _PE is obtained from the rotation angle θ _OUT .

[0030] At step 45, the phase compensation amount P _D is determined by the difference between the target phase delay P _E ^* and the actual phase delay P _E.

[0031] At step 46, the control command phase compensation amount P _D is obtained is output to the DC motor 7c. It should be noted that the control command is passed through a high-pass filter to apply a driving force of only a high-frequency component to the DC motor 7c.

Note that the above steps 42 to 46
It corresponds to steering characteristic control means.

(A) At the time of low-frequency steering input The steering frequency fθ input from the steering wheel 1
Is in the low frequency region below the set frequency fθ ₀ ,
Only the processing of Step 40 → Step 41 → Step 42 is repeated, and the phase compensation by the steering actuator 7 is not performed.

Therefore, the steering input is: steering wheel 1 → constant velocity joint 2 → upper steering shaft 3
→ Rubber coupler 6 → Lower steering shaft 5 →
The steering wheel is transmitted to the steering mechanism 4 and the steered wheels are steered according to the steering input.

That is, when the operating characteristics of the driver are the characteristics shown in FIG. 5 and the transfer characteristics of the rubber coupler 6 are the characteristics shown in FIG. 6, the phase characteristics in the low frequency region are the driver operating phase characteristics P _A ( f) Rubber transfer phase characteristics P
_B (f) is combined with the phase characteristic P _C (f), and the gain characteristic in the low frequency region is a gain obtained by combining the driver operation gain characteristic g _A (f) with the rubber transfer gain characteristic g _B (f). Characteristic g
_C (f).

(B) At the time of high frequency steering input The steering frequency fθ input from the steering wheel 1
Is in the high frequency region above the set frequency fθ ₀ ,
The flow proceeds to step 40 → step 41 → step 42 → step 43 → step 44 → step 45 → step 46, and the phase compensation by the steering actuator 7 is performed.

That is, looking at the characteristics of the actual steering, the rubber coupler 6 transmits the input in the low frequency region and transmits the input in the high frequency region.
As a means for absorbing the input, the steering input is absorbed by the rubber coupler 6 and the phase is greatly delayed to the lower steering shaft 5 (phase characteristic in FIG. 7), and the gain is reduced (gain in FIG. 7). (Characteristics) Steering input is transmitted.

[0038] However, the output by the processing of step 43 to step 46, the control command obtaining a phase compensation quantity P _D determined by the difference between the target phase delay P _E ^* and the actual phase delay P _E is the DC motor 7c As a result, the phase lag is compensated by an external control input from the steering actuator 7.

For example, when the compensation characteristic of the controller 10 is the characteristic shown in FIG. 8, as shown in FIG. 9, the phase advance operation generated by the steering actuator 7 is superimposed on the phase delay in the high frequency region, and as shown in FIG. The actual phase characteristic P _E (f) after phase compensation shown by the solid line 9 substantially matches the target phase characteristic P _E ^* (f) shown by the broken line in FIG. In addition, this first
In the embodiment, since the gain is not compensated, the gain characteristic does not change.

Therefore, in the case of an elderly driver or the like and the operation characteristic of the driver is a characteristic having a large phase delay, a large amount of phase compensation P _D is given in a high frequency region.
Also, in the case of a young driver, etc., in which the operation characteristics of the driver have a small phase lag, a small amount of phase compensation P _D can be given in a high frequency region, regardless of the variation in the operation characteristics of the driver. As a result, it is possible to obtain a constant steering phase characteristic that substantially matches the target phase characteristic P _E ^* (f).

The target phase characteristic P _E ^* (f) is set to an optimum characteristic that does not cause a feeling of steering discomfort at the time of turning or lane change where a high frequency component is required for steering.

[0042] Here, when the high frequency range the phase lag compensation by the steering actuator 7, but accompanied steering discomfort is concerned the compensation operation, incoming rubber coupler 6 is in the low frequency range
Since this is a means for transmitting a force and absorbing an input in a high frequency range, a compensation input from the steering actuator 7 is hardly transmitted to the steering wheel 1 via the upper steering shaft 3.

(C) When the phase compensation control system fails When the phase compensation control system such as the controller 10 fails,
Even when the high frequency region phase delay compensation is not performed, the steering wheel 1 and the steering mechanism 4 are mechanically connected by the upper steering shaft 3, the rubber coupler 6, and the lower steering shaft 5,
As shown in FIG. 7, if the steering input is in a low frequency range, steering is performed as usual, and even if the steering input is in a high frequency range, only a phase delay occurs, and high security is ensured. .

(D) At the time of road surface disturbance input It is conceivable that unevenness of the road surface becomes a direct disturbance and the steering mechanism 4 operates. However, the road surface disturbance such as unevenness is basically a low frequency of 0.1 Hz or less, which is the same as the conventional steering system because of the transmission characteristics of the rubber coupler 6 as shown in FIG. is there. Therefore, this configuration does not cause any particular problem.

On the other hand, with respect to the frequency of 0.1 Hz or more, for example, the steering input from the steering angle sensor 8 and the rotation angle sensor 9
By comparing the steering output from the DC motor 7 and operating the DC motor 7c so as to suppress its movement against disturbance from the road surface, a system that is stable against disturbance can be configured. However, in everyday driving, even if you do not do so far,
If the characteristics shown in FIG. 6 are made easy to transmit to the input frequency of the disturbance, it is considered that there is no particular problem.

That is, for the fundamental frequency of the disturbance,
It is the same as the conventional system, and there is very little problem at a high frequency.

As described above, the vehicle steering system according to the first embodiment has the following effects.

(1) In a vehicle steering system that steers the steered wheels in response to a steering input from a driver, a low-frequency component of the steering input is mechanically transmitted through a rubber coupler 6 and is transmitted through the rubber coupler 6. This device compensates only the phase delay of the transmitted high-frequency component by electrical control, so it has a higher operating cost while ensuring higher safety at a more advantageous system cost than conventional steer-by-wire devices. The steering characteristics of the vehicle can be optimized for any driver having different vehicle steering characteristics.

(2) A rotation angle sensor 9 for detecting the steering characteristics of the vehicle is provided, and a feedback control system for checking the characteristics of the actual steering is configured as a phase compensation control system. Since the apparatus obtains P _E (f), it is possible to always obtain the optimum constant phase characteristic with respect to the steering input with high accuracy regardless of the change over time in the transfer characteristic of the rubber coupler 6 or the like.

[0050] (Second Embodiment) Next, a steering apparatus will be described for a vehicle of the second embodiment corresponding to the invention of claim 3, wherein.

First, the configuration will be described.

The configuration differs from the first embodiment shown in FIG. 2 in that the rotation angle sensor 9 is not provided. Since other configurations are the same as those of the first embodiment, the corresponding components are denoted by the same reference numerals and description thereof is omitted.

Next, the operation will be described.

FIG. 11 is a flowchart showing the flow of the steering characteristic control processing operation performed by the controller 10 '.
Hereinafter, each step will be described.

In step 50, it is determined whether the ignition key has been turned on.

In step 51, a steering frequency fθ is calculated by differentiating the steering angle θ _IN from the steering angle sensor 8 (corresponding to a steering frequency detecting means), and the steering frequency fθ and the initial phase compensation shown in FIG. Initial compensation is performed based on the characteristics.

In step 52, the operating condition of the driver is observed for a unit time based on the steering angle θ _IN from the steering angle sensor 8 to measure the steering spectrum of the driver, and the power in the high frequency component (for example, 0.5 Hz or more) is measured. Calculate the area value of the spectrum.

In step 53, it is determined whether or not the power spectrum area value is smaller than the set value 1.

At step 54, it is determined whether or not the power spectrum area value exceeds the set value 2 (> set value 1).

In step 55, when the power spectrum area value exceeds the set value 2, a command for performing phase compensation by the compensation characteristic 1 of the stepwise phase compensation characteristics of FIG. 14 is output.

In step 56, when the power spectrum area value is equal to or more than the set value 1 and equal to or less than the set value 2, a command for performing phase compensation by the compensation characteristic 2 among the stepwise phase compensation characteristics of FIG. 14 is output.

In step 57, when the power spectrum area value is smaller than the set value 2, a command for performing phase compensation by the compensation characteristic 3 of the stepwise phase compensation characteristics of FIG. 14 is output. In step 58, the ignition key is turned off.
It is determined whether or not it is ON.
Step 57 is repeated.

Steps 51 to 57 correspond to steering characteristic control means.

When the vehicle equipped with the device of the second embodiment is turned on with the ignition key turned on to start the operation, in step 51, the phase of the phase in the high frequency region is determined by the steering actuator 7 based on the initial compensation characteristic Pj (f) of FIG. Is compensated,
As shown in FIG. 13, the phase characteristics of the entire system include:
This is a characteristic in which the initial compensation characteristic Pj (f) is superimposed on the driver operation characteristic + rubber transfer characteristic Pi (f). The initial compensation characteristic Pj (f) is set on the assumption that a driver having a normal phase response is used.

However, some drivers originally have operation characteristics with a small phase delay in a high frequency region, and others have operation characteristics with a large phase delay. Therefore, it is necessary to grasp the operating characteristics of the driver. This is performed in step 52, in which the operating characteristics of the driver are estimated by measuring the steering spectrum of the driver. That is,
If the power spectrum area value in the high frequency range is small, it can be estimated that the driver requires large phase compensation. Conversely, if the power spectrum area value in the high frequency range is large, a small phase compensation is used. It can be estimated that there is enough driver.

As described above, the operation characteristics of the driver are estimated when the vehicle travels for a predetermined time or a predetermined distance, and the phase compensation is performed by selecting a compensation characteristic suitable for the estimation characteristic instead of the initial compensation characteristic. This is the process of step 57.

Therefore, also in the second embodiment,
As in the first embodiment, an optimum steering phase characteristic can be obtained irrespective of variations in the driver's operation characteristics. Other operations such as a failure of the phase compensation control system and an input of road disturbance are the same as those of the first embodiment.

As described above, in the device of the second embodiment, the following effect is obtained in addition to the effect (1) in the device of the first embodiment.

(3) Since only the steering angle sensor 8 is used to perform stepwise phase compensation by estimating and detecting the driver's operation characteristics by measuring the driver's steering spectrum, a control system such as an input and an arithmetic processing is required. The optimum phase characteristics can be obtained regardless of the variation in the driver's operation characteristics, with a simple practical system.

(Third Embodiment) Next, a vehicle steering system according to a third embodiment of the present invention will be described.

The structure is the same as that of the first embodiment, and a description thereof will be omitted.

Regarding the operation, the driver operation characteristic in FIG. 5, the rubber transmission characteristic in FIG. 6, and the characteristic of the actual steering in FIG. 7 are the same, and the compensation characteristic of the controller 10 in FIG.
Of the controller 10 is used. That is, when the steering frequency is in a high frequency range, both phase compensation and gain compensation are performed.

As a result, as shown in FIG. 16, the total characteristic of the driver + compensation control is such that the gain is flat and the phase delay is suppressed, and both the steering wheel 1 undercut and the phase delay are reduced. Can be improved.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and any changes or additions without departing from the spirit of the invention are included in the invention. It is.

For example, in the embodiment, a rubber coupler is shown as an example of the coupling, but an electrorheological fluid coupling 11 as shown in FIG. 17 may be used.

The electrorheological fluid coupling 11 includes an input member 11a fixed to the upper steering shaft 3 and an output member 11b fixed to the lower steering shaft 5.
And an electrorheological fluid 11c sealed between the input member 11a and the output member 11b, and a voltage source 11d for applying a voltage to the electrorheological fluid 11c.
When the steering frequency is in a low frequency range, the electrorheological fluid 11c
A high voltage is applied to the steering wheel to mechanically transmit the steering input as a hard substance having an increased stiffness. When the steering frequency is in a high frequency range, the applied voltage of the electrorheological fluid 11c is set to zero, and the state where the fluid viscosity is the lowest To absorb the steering input. The transfer characteristics of this electrorheological fluid coupling 11 are as follows:
When the cutoff frequency is 0.5 Hz, the result is as shown in FIG.

Further, as the joint, a fluid clutch or the like that utilizes the viscosity of the fluid and does not transmit a fast motion but transmits only a slow motion is also conceivable.

In the embodiment, the example in which the gear system of the steering actuator 7 is directly connected to the DC motor 7c has been described. However, a clutch may be provided between the gear system and the DC motor 7c. In this case, when the DC motor 7c is locked, the steering operation can be ensured by disengaging the clutch by a self-diagnosis (difference between the sensors 8 and 9) by a computer or a driver operation.

Although the first embodiment shows an example in which one characteristic is set as the target phase characteristic, a plurality of target phase characteristics are set, and the driver selects from the plurality of characteristics to select the target phase characteristic. May be determined. In this case, a phase characteristic according to the driver's preference can be obtained.

In the second embodiment, an example is shown in which three stages of compensation characteristics are set in order to compensate the phase stepwise. However, the number of stages is not limited to the embodiment, and the number of stages is not limited to two. Also, three or more stages may be used.

[0081]

In the present invention of claim 1, wherein as has been described above, according to the present invention, a vehicle steering apparatus for steering the steered wheels in accordance with steering input from the driver, the upper steering
Between the ring shaft and the lower steering shaft.
At least the low frequency input from one shaft.
A joint that reaches and absorbs the input in the high-frequency region is interposed.The low-frequency component of the steering input is transmitted mechanically through the joint, and only the phase delay of the high-frequency component transmitted through the joint is electrically transmitted. Because it is a means to compensate by control ,
As compared with the steer-by-wire system , the advantage is obtained that the steering characteristics of the vehicle can be optimized for all drivers having different operation abilities while securing high safety at an advantageous system cost. Also, the auxiliary rudder
Auxiliary steering angle mechanism when compensating for phase lag in high frequency region with angle mechanism
The high frequency range compensation input from is absorbed by the joint,
Steering wheel via upper steering shaft
The compensation input is hardly transmitted to the controller.

Further, in the present invention described in claim 2,
When the detected steering frequency is in a high frequency region, the steering wheel is controlled in a high frequency region.
With the phase delay of turning the steered wheels with respect to the steering input
Because of the means for compensating for the reduction of the steering wheel, it is possible to improve both the insufficient turning of the steering wheel and the phase delay. Further, according to the present invention described in claim 3,
The steering characteristic control means is used to detect the detected steering frequency.
Is in the high frequency range, stearin in the high frequency range
Phase of steering of steered wheels with respect to steering input of wheel a
The power spectrum in the high frequency range at the steering input.
Compensation characteristics set by compensation characteristics setting means according to
Means to compensate based on
While the system is simple and practical,
Optimum phase characteristics are obtained regardless of variations in operation characteristics
be able to.

[Brief description of the drawings]

FIG. 1 is a view corresponding to a claim showing a vehicle steering system of the present invention.

FIG. 2 is an overall system diagram showing a vehicle steering system according to a first embodiment.

FIG. 3 is a sectional view showing a rubber coupler of the first embodiment.

FIG. 4 is a flowchart showing a flow of a phase compensation control operation performed by a controller of the apparatus of the first embodiment.

FIG. 5 is an operation characteristic diagram of a driver.

FIG. 6 is a transfer characteristic diagram of the rubber coupler.

FIG. 7 is a characteristic diagram of actual steering in which the operation characteristics of the driver and the transmission characteristics of the rubber coupler are combined.

FIG. 8 is a compensation characteristic diagram of a controller in the first embodiment device.

FIG. 9 is a steering characteristic diagram after phase compensation is performed by the first embodiment device.

FIG. 10 is an overall system diagram showing a vehicle steering system according to a second embodiment.

FIG. 11 is a flowchart showing a flow of a phase compensation control processing operation performed by a controller of the device of the second embodiment.

FIG. 12 is an initial compensation characteristic diagram in the device of the second embodiment.

FIG. 13 is an overall characteristic diagram of the system when initial compensation is performed in the apparatus of the second embodiment.

FIG. 14 is a diagram showing a stepwise phase compensation characteristic of the controller of the device of the second embodiment.

FIG. 15 is a diagram illustrating gain and phase compensation characteristics in a controller of the device of the third embodiment.

FIG. 16 is a steering characteristic diagram as a total of a driver + controller in the device of the third embodiment.

FIG. 17 is a sectional view showing an electrorheological fluid coupling which is another example of the coupling.

FIG. 18 is a transmission characteristic diagram of the electrorheological fluid coupling.

FIG. 19 is a view showing a conventional mechanical vehicle steering system.

FIG. 20 is a diagram showing a conventional steer-by-wire steering apparatus for a vehicle.

FIG. 21 is a graph showing driver operation characteristics for each age group (20s and 80s).

FIG. 22 is a traveling locus characteristic diagram in a case where a course is formed in which snakes pass between pylons arranged at equal intervals.

[Explanation of symbols]

 a Steering wheel b Upper steering shaft c Steering wheel d Steering mechanism e Lower steering shaft f Joint g Auxiliary steering angle mechanism h Steering frequency detecting means i Steering characteristic control means

Claims (3)

(57) [Claims] An upper steering shaft coupled to a steering wheel; a lower steering shaft coupled to a steering mechanism for steering a steered wheel; and at least one interposed between the upper steering shaft and the lower steering shaft. And a joint that transmits an input in a low frequency range from a shaft and absorbs an input in a high frequency range, and is provided on the lower steering shaft or the steering mechanism, and can provide an auxiliary steering angle by an external command. An auxiliary steering angle mechanism capable of detecting the steering frequency input from the steering wheel; and a steering frequency detection means for detecting a steering frequency input from the steering wheel.
A steering characteristic control unit that outputs a command for compensating for a phase delay of turning of the steered wheels to the auxiliary steering angle mechanism. 2. A vehicle steering apparatus according to claim 1, wherein the steering characteristic control means, when the detected steering frequency is the high frequency range, the steering wheel in a high frequency region
With the phase delay of the steering of the steered wheels to the steering input of the wheel
A vehicle steering system comprising means for outputting a command for compensating for a decrease in gain to the auxiliary steering angle mechanism. (3) The steering apparatus for a vehicle according to claim 1.
hand, Based on the steering frequency detected by the steering frequency detection means.
The power spectrum in the high frequency region at the steering input
Power spectrum area calculating means for calculating the area, Steering input calculated by the power spectrum area calculation means
Depending on the power spectrum area of the high frequency region in force
Input of the steering wheel in the high frequency range
To set the phase lag compensation characteristic of the steering of the steered wheels with respect to
Compensation characteristic setting means, When the detected steering frequency is high,
High in the wavenumber range Steering wheel in frequency domain
The phase lag of turning the steered wheels with respect to the steering input of the
Compensation based on the compensation characteristics set by the compensation characteristics setting means
Means for outputting a command to the auxiliary steering angle mechanism.
A vehicle steering system characterized by the above-mentioned.