JP2015214295A - Power steering device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power steering device of a vehicle which can induce an occupant to a specified steering feeling by an operation of a steering wheel.SOLUTION: A power steering device 1 which assists the steering of a steering wheel 2 comprises: a steering angle sensor 22 which detects a steering angle; a torque sensor 21 which detects steering torque; and a control unit 10 which controls an assist force of an electric motor 8 so as to reach a target steering force characteristic M which is regulated by a plurality of characteristic elements Ax to Jx. The control unit 10 has: a feeling amount setting part 15 which sets a plurality of feeling amounts A to J which are a plurality of the feeling amounts A to J corresponding to a plurality of the characteristic elements Ax to Jx, and estimated to be generated at the occupant on the basis of a steering feeling which is generated at the occupant; and a steering force characteristic setting part 16 which converts a plurality of feeling amounts A1 to J1 which are set by the feeling amount setting part 15 to physical amounts of a plurality of the characteristic elements Ax to Jx, and sets a target steering force characteristic M.

Description

  The present invention relates to a power steering apparatus for a vehicle, and more particularly to a power steering apparatus for a vehicle that sets a target steering force characteristic by converting an occupant's sensory amount into a physical quantity in a traveling characteristic of the vehicle.

  2. Description of the Related Art Conventionally, an electric power steering apparatus in which power of an electric motor is applied to a steering mechanism such as a steering shaft or a rack shaft so as to reduce the operating force of a steering wheel by an occupant has been put to practical use. This type of electric power steering apparatus includes a direct drive system in which the steering mechanism is directly driven by an electric motor, and a hydraulic pump that is driven by the electric motor, thereby providing assist force to the steering mechanism by the hydraulic pressure generated by the hydraulic pump. There is an indirect driving method to be applied.

Normally, in an electric power steering apparatus, control is performed so that the correlation of steering torque with respect to the steering angle of the steering wheel becomes a target steering force characteristic determined for each vehicle.
This target steering force characteristic is defined by a plurality of specific factors such as reaction force generated at a predetermined steering angle and the size of hiss, and the product concept of the vehicle (for example, driving with a light feeling) by the operation of the steering wheel by the occupant. It is designed to achieve driving characteristics that suit the driving characteristics of the car and heavy driving.

  If the occupant's human factors, such as gender, age, physique, physical condition, etc., are different, the steering feeling generated for a given steering force (eg, lightness, profound feeling, etc.) varies from occupant to passenger, Depending on the weather, topography, traffic conditions, etc., the occupant's steering feeling generated for a given steering force will be different. Therefore, there is a case where the occupant cannot feel the steering feeling as intended even if the target steering force characteristic is set uniformly according to the vehicle product concept at the design stage.

Although the user hospitality system for automobiles of Patent Document 1 is not an electric power steering device, it grasps the situation related to the use of automobiles by combining the type of disturbance stimulus and the hospitality intention classification item, and refers to the intention estimation table to ensure safety. The standard intention parameter value that gives the strength standard of hospitality intention in each of the categories of safety, convenience and comfort is determined, and the standard intention parameter value specific to each situation related to vehicle use is used as the standard of intention strength. The intention strength parameter value is determined in consideration of the disturbance stimulus value, and the operation of the in-vehicle device is autonomously controlled.
Accordingly, the mental state of the occupant can be estimated from the biological information of the occupant, and the mental state of the occupant can be guided in the improvement direction by adjusting the cabin lighting, sound, air conditioning, and the like.

Japanese Patent No. 4332813

The automobile user hospitality system of Patent Document 1 indirectly estimates the occurrence of mental stress from the state of the occupant (biological information), and adjusts the driving environment (indoor environment) of the occupant by adjusting the in-vehicle device mounted on the vehicle. By changing or alleviating or eliminating the cause of stress, the mental state of the occupant is guided in an improvement direction.
However, the technique of Patent Document 1 uses an incidental function of the vehicle, and adjusts the steering feeling of the occupant using the essential function of the vehicle, that is, the sense of operation of the steering wheel by the occupant. is not. Further, the technique of Patent Document 1 eliminates the type of stress generated according to the type of mental stress generated in the occupant. It does not induce you to feel the ring.

Therefore, if the target steering force characteristic based on the steering feeling generated in the occupant can be set in advance, the occupant's sense can be positively induced so that the occupant feels a specific steering feeling.
However, it is not easy to quantify the human sense of sensation into a physical quantity in the driving characteristics of the vehicle, and no technology has yet been proposed for guiding the occupant to feel a specific steering feeling. It has not been put into practical use.

  An object of the present invention is to provide a vehicle power steering device or the like that can guide an occupant to a specific steering feeling by operating a steering wheel.

  The power steering device for a vehicle according to claim 1 is a power steering device for a vehicle that assists steering of a steering wheel by assist means, a steering angle sensor that detects a steering angle, a torque sensor that detects a steering torque, and a plurality of characteristics. Control means for controlling the assist force of the assist means so as to achieve a target steering force characteristic defined by an element, and the control means corresponds to the plurality of characteristic elements based on a steering feeling generated in an occupant. Sensory quantity setting means for setting a plurality of sensory quantities that are estimated to occur to the occupant, and converting the sensory quantity set by the sensory quantity setting means into physical quantities of the plurality of characteristic elements And steering force characteristic setting means for setting the target steering force characteristic.

  The power steering apparatus for a vehicle includes a sensory amount setting unit that sets a plurality of sensory amounts based on a steering feeling generated by an occupant, and the sensory amount set by the sensory amount setting unit is converted into a plurality of characteristic elements. Since the target steering force characteristics are set by converting to physical quantities, the occupant's steering feeling can be adjusted using the sensation of the steering wheel by the occupant, and the occupant's sense is positively felt to feel a specific steering feeling. Can be guided.

  According to a second aspect of the invention, in the first aspect of the invention, the sensory amount setting means sets the plurality of sensory amounts based on a relational expression between the steering feeling and the plurality of sensory amounts. According to this, a plurality of sensory quantities can be easily set using the relational expression.

  A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the sense amount setting means determines the steering feeling using a running state of a vehicle. According to this, the steering feeling can be adjusted in accordance with an external factor that affects the occupant's sense.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the steering force characteristic setting means converts the plurality of sensory quantities into physical quantities of the plurality of characteristic elements using Fechner's law. It is characterized by that. According to this, it is possible to set a target steering force characteristic by quantifying a plurality of sensory quantities into physical quantities in the running state.

  The invention of claim 5 is the invention according to any one of claims 1 to 4, wherein the steering force characteristic setting means increases or decreases the assist force at least in a range of a steering angle of 30 ° to 120 °. Yes. According to this, since the steering feeling is adjusted in a region where the force of one hand of the occupant is larger than the other, the steering feeling of the occupant can be efficiently guided.

  According to the power steering device for a vehicle of the present invention, an occupant can be guided to a specific steering feeling by operating a steering wheel.

1 is a perspective view of a power steering device for a vehicle according to a first embodiment. It is a block diagram of a control unit. The target steering force characteristic set by the steering angle and the steering torque is shown, (a) shows the target steering force characteristic of the standard type vehicle, (b) shows the target steering force characteristic of the heavy type vehicle, (c) ) Is a diagram showing target steering force characteristics of a linear vehicle. It is a figure which shows the sensory characteristic when the steering torque of Fig.3 (a)-FIG.3 (c) is represented by the perceptual steering torque which the passenger | crew perceived. It is a figure which shows the sensory characteristic when a reference value is used. It is a figure which shows the sensory characteristic at the time of exciting mode execution.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The following description exemplifies a case where the present invention is applied to a vehicle, and does not limit the present invention, its application, or its use.

Embodiment 1 of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, a power steering device 1 of a vehicle V includes a steering wheel 2, and the steering wheel 2 is connected to an upper end portion of a steering shaft 3, and a steering force for steering the steering wheel 2 is steered. It is configured to be transmitted to the shaft 3. An upper end portion of the intermediate shaft 4 is connected to the lower end portion of the steering shaft 3 via a universal joint, and a steering gear box 5 is provided at the lower end portion of the intermediate shaft 4. Tie rods 6 are connected to both sides of the steering gear box 5, and wheels 7 are attached to these tie rods 6, respectively.

A rack and pinion mechanism (not shown) is provided inside the steering gear box 5, and a lower end portion of the intermediate shaft 4 is connected to the pinion.
On the other hand, wheels 7 are connected to both ends of the rack via tie rods 6.
The steering gear box 5 is provided with an electric motor 8 for applying a force to the pinion side via a reduction gear (not shown). The electric motor 8 is electrically connected to a control unit 10 (control means). Yes.

As shown in FIG. 2, the control unit 10 includes a first control unit 11, a second control unit 12, a motor current control unit 13, and the like, and has a predetermined target steering force characteristic set by the control unit 10. The electric motor 8 is controlled so as to be realized.
The power steering apparatus 1 includes a torque sensor 21 for detecting a steering torque acting on the steering shaft 3 or the intermediate shaft 4, a steering angle sensor 22 for detecting a steering angle, and a vehicle speed sensor 23 for detecting a vehicle speed. A lateral G sensor 24 that detects lateral acceleration, a human factor sensor 25 that detects occupant biological information, an external factor sensor 26 that detects travel environment information, and a mode changeover switch 27. These output values are configured to be input to the control unit 10.

The human factor sensor 25 is capable of detecting a plurality of occupant biological information (for example, finger plethysmogram, blood flow, brain wave, myoelectricity, line of sight, voice, etc.), occupant driving skill, occupant operation speed, and the like. It consists of a detection device. The biological information is detected by a sensor attached to the gripping position of the steering wheel 2, a sensor attached to the seat, an eye sensor attached to the rearview mirror, a vehicle interior microphone (all not shown), and the like.
In addition, the vehicle V evaluates the occupant's driving skill from the behavior information of the vehicle V, and also displays the driving cycle fuel efficiency and the driving evaluation result on a display (for example, JP 2012-197006 A). Therefore, the driving skill and the operation speed obtained by the driving support device are input to the control unit 10.
The external factor sensor 26 includes a plurality of detection devices that can detect the terrain where the vehicle V is traveling, road conditions, weather, time, traffic conditions, and the like. When the detection item of the external factor can be acquired by the navigation device (not shown), the external factor sensor 26 may be substituted by the navigation device.

The mode changeover switch 27 is a switch for changing the sense of operation of the steering wheel 2 by the occupant. The mode changeover switch 27 has a plurality of (for example, four) specific modes for actively guiding the occupant's feeling to a specific steering feeling (exciting mode, light mode, heavy mode, linear mode), An automatic mode for automatically determining the mental state and allowing the vehicle V to autonomously guide the occupant's feeling in the improvement direction can be selected.
In the above-described driving support device, since the driving state determination such as the supple driving state, the swaying driving state, and the gentle driving state is performed, it is possible to indirectly determine the occupant's mental state based on the driving state.

As shown in FIG. 2, the first control unit 11 is a control unit that controls the electric motor 8 so as to decrease the output value of the torque sensor 21, and assist force in a direction that reduces steering torque (steering force). The electric motor 8 is controlled so as to generate.
The first control unit 11 receives the torque sensor value detected from the torque sensor 21, the noise of the torque sensor value is cut by a filter (not shown), and a reference target current based on the torque sensor value by a predetermined control gain. Io is calculated. The control gain is set based on the values of the vehicle speed sensor 23 and the lateral G sensor 24.

The second control unit 12 is a control unit for controlling the electric motor 8 so that the target steering torque is set in advance, and the value of the steering angle is input from the steering angle sensor 22, and the value of the steering angle and A target steering torque is calculated based on the target steering force characteristic M (see, for example, FIG. 3).
The target steering force characteristic M is set so that the occupant's sensation can be induced so as to feel a specific steering feeling using the operational sensation of the steering wheel 2.

Here, the target steering force characteristic M will be described.
The target steering force characteristic M is defined by 10 characteristic elements.
The characteristic elements Ax to Jx are as follows.
Ax: Steering angle (deg.) At which reaction force is 20N or more
Bx: Reaction force with a steering angle of 30 ° (N)
Cx: Maximum reaction force (N)
Dx: Inclination angle (deg.) With a steering angle of 30 ° to 120 °
Ex: Linearity of steering angle of 30 ° to 120 ° Fx: coefficient a obtained by approximating y = ax ² + bx + c by the least square method in the shape of the steering angle of 30 ° to 120 °
Gx: coefficient b obtained by approximating y = ax ² + bx + c by the least square method in a shape with a steering angle of 30 ° to 120 °
Hx: coefficient c obtained by approximating y = ax ² + bx + c by the method of least squares in a shape with a steering angle of 30 ° to 120 °
Ix: 30 ° hiss size (N)
Jx: 120 ° hiss size (N)

As shown in FIG. 2, the second control unit 12 includes a feeling estimation unit 14, a sensory amount setting unit 15 (sensory amount setting unit), and a steering force characteristic setting unit 16 (steering force characteristic setting unit). ing.
When the automatic mode is selected by the mode changeover switch 27, the feeling estimation unit 14 inputs detection values from the human factor sensor 25 and the external factor sensor 26, and based on these detection values, senses of the current occupant are obtained. A specific mode for estimating and improving the estimation result is instructed to the sensory amount setting unit 15. For example, when the traffic factor is detected by the external factor sensor 26 and the blood flow of the occupant is weak and the operation speed by the occupant is reduced by the human factor sensor 25, it is estimated that the occupant is in a fatigued state. Is executed, and the sensory quantity setting unit 15 is instructed to execute the light mode.

The sensory amount setting unit 15 is configured to be able to set a plurality of sensory amounts A1 to J1 in order to set the target steering force characteristic M based on the equations (1) to (4). The sensory amount setting unit 15 selects formulas (1) to (4) corresponding to the mode to be executed, and determines specific sensory amounts A to J that need to be adjusted.
Exciting feeling = −0.02A−0.03B−0.05C + 0.02D−0.16E−0.02F−0.01G + 0.02H + 0.02I−0.14J + 4.27 (1)
Light feeling = −0.02A + 0.03B−0.18C−0.01D−0.35E−0.03F−0.02G + 0.04H + 0.16I−0.27J + 3.47 (2)
Heavy feeling = −0.11A + 0.09B + 0.15C−0.01D−0.45E + 0.16F−0.10G + 0.09H−0.19I + 0.26J + 4.80 (3)
Linear feeling = −0.16A + 0.19B + 0.05C + 0.002D−0.06E + 0.08F−0.09G + 0.14H−0.20I−0.17J + 4.73 (4)

Expressions (1) to (4) are respectively set for four types of steering feelings: an exciting feeling, a light feeling, a profound feeling, and a linear feeling. These formulas (1) to (4) have individual steering feelings reflecting sensations occurring in the occupant corresponding to the characteristic elements Ax to Jx, respectively, and the sensation amounts A to J estimated to occur in the occupant as parameters. It is expressed. Each sensory amount AJ is as follows.
A: Steering angle (deg.) At which the reaction force is 20 N or more
B: Reaction force with a steering angle of 30 ° (N)
C: Maximum reaction force (N)
D: Inclination angle (deg.) Of a sense amount with a steering angle of 30 ° to 120 °.
E: Linearity of steering angle 30 ° to 120 ° F: Coefficient a approximating y = ax ² + bx + c by the least square method in the shape of steering angle 30 ° to 120 °
G: coefficient b obtained by approximating y = ax ² + bx + c by the least square method in the shape of the steering angle of 30 ° to 120 °
H: Coefficient c obtained by approximating y = ax ² + bx + c by the method of least squares in the shape of the steering angle 30 ° to 120 °
I: His size of 30 ° (N)
J: Size of His at 120 ° (N)

Here, the setting method of Formula (1)-Formula (4) is demonstrated.
FIG. 3A to FIG. 3C show the target steering force characteristics of the vehicle corresponding to the standard type, the heavy type, and the linear type, respectively. For vehicles with these target steering force characteristics, a plurality of subjects actually operated the steering wheel and measured how much steering torque was perceived as a sensation.

4 (a) to 4 (c), the correlation between the steering angle corresponding to each of FIGS. 3 (a) to 3 (c) and the perceived steering torque (sensory amount) perceived by the occupant (hereinafter referred to as “the steering angle”). Sensory characteristics).
Based on this measurement result, the larger the steering angle, the smaller the actual steering torque tends to feel (low steering torque), and the steering angle 30 ° to 120 ° corresponding to the region where the force of one hand of the occupant is greater than the other. The sensory features associated with the steering operation are extracted such that the linearity features tend to feel smaller (linear shape) than the actual nonlinearity.
As described above, with respect to the plurality of characteristic elements, the weighting factors associated with the sensory amounts A to J are obtained for each steering feeling based on the sense of steering operation perceived by the occupant, and the equations (1) to (4) are obtained. Guided.

When the sensory amounts A1 to J1 for guiding the occupant to a specific steering feeling are set based on any one of the expressions (1) to (4), the absolute value of the weighting coefficient is 0.2 or more. The specific feeling feeling values A to J are adjusted to increase a specific steering feeling value.
Here, in the case of a feeling of excitement in which there are no sensory quantities A to J having an absolute value of the weighting factor of 0.2 or more, the sensory quantities E and J having large absolute values are adjusted to increase the value of the excitement. . Specifically, when increasing the value of the feeling of sensation, the sensation quantity E1 in which the negative sensation quantities E and J in which the absolute value of the weighting coefficient is close to 0.2 in Formula (1) is smaller than the reference values E0 and J0. , J1 is set. The sensory amounts A1 to D1 and the sensory amounts F1 to I1 are set to reference values A0 to D0 and F0 to I0. The reference values A0 to J0 are set at the design stage according to the product concept and stored in advance as initial values.

Similarly, in order to increase the value of lightness, in equation (2), the sensory amount E1 in which the negative sensory amounts E and J having an absolute value of the weighting coefficient of 0.2 or more are smaller than the reference values E0 and J0. , J1 is set. The sensory amounts A1 to D1 and the sensory amounts F1 to I1 are reference values A0 to D0 and F0 to I0.
In order to increase the value of profound feeling, in Equation (3), a negative sensory amount E having an absolute value of the weighting factor of 0.2 or more is set to a sensory amount E1 smaller than the reference value E0, and the weighting factor of A sensory amount J1 is set in which a positive sensory amount J having an absolute value of 0.2 or more is set larger than the reference value J0. The sensory amounts A1 to D1 and the sensory amounts F1 to I1 are reference values A0 to D0 and F0 to I0.
In order to increase the value of the linear feeling, in Equation (4), a sensory amount I1 is set in which the positive sensory amount I having a weighting coefficient absolute value of 0.2 or more is smaller than the reference value I0. The sensory amounts A1 to H1 and J1 are reference values A0 to H0 and J0.

When the specific mode is selected by the mode changeover switch 27 or when the execution of the specific mode is instructed from the feeling estimation unit 14 during the execution of the automatic mode, the sense amount setting unit 15 selects the selected formula (1). The sensory amounts A1 to J1 are set based on the expression (4).
The sensory amounts A1 to J1 newly set based on the equations (1) to (4) are output to the steering force characteristic setting unit 16. The newly set sensory quantities A1 to J1 are expressed as sensory characteristics Me that define the correlation between the steering angle (deg.) And the perceived steering torque (N) perceived by the occupant. The perceived steering torque of the sensory characteristic Me corresponds to the sensory reaction force that the occupant receives from the steering wheel 2. When the mode changeover switch 27 is turned off, the reference values A0 to J0 all shift to the sensory amounts A1 to J1.

As shown in FIG. 2, the steering force characteristic setting unit 16 converts the sensory amounts A1 to J1 (sensory characteristic Me) input from the sensory amount setting unit 15 into characteristic elements Ax to Jx that are physical quantities, and the target steering force. Set characteristic M. In converting into physical quantities, the sensory strength is proportional to the logarithm of the stimulus strength (Fechner's law), so the sensory amounts A1 to J1 are converted into physical quantities according to the following equation (5).
R = klogS + K (5)
R is a sensory amount, S is a steering torque, and K is an integral constant.

  The second control unit 12 obtains a deviation between the target steering torque calculated from the target steering force characteristic M and the torque sensor value from the torque sensor 21, and calculates a compensation current If using the deviation and a predetermined control gain. Yes. The control gain is set based on the values of the vehicle speed sensor 23 and the lateral G sensor 24. The target current I is calculated by adding the reference target current Io and the compensation current If.

  The motor current control unit 13 performs feedback control for setting the current supplied to the electric motor 8 to Im. Therefore, the motor current control unit 13 includes a PI control unit that performs proportional-integral control, a motor characteristic compensation unit, and the like (all not shown).

Next, the operation and effect of the vehicle power steering apparatus 1 according to this embodiment will be described.
When the mode changeover switch 27 is turned off, the sensory amounts A1 to J1 are not newly set, and the reference values A0 to J0 set in the design stage are maintained and used. As shown in FIG. A sensory characteristic Me based on the reference values A0 to J0 is set, and a target steering force characteristic M obtained by converting the sensory characteristic Me into a physical quantity in the running characteristic is set.
When the exciting mode is selected by the occupant operation or the automatic mode, the shape of the steering angle of 30 to 120 ° is made non-linear as shown in FIG. A sensory characteristic Me in which the reaction force of His is reduced is set, and a target steering force characteristic M obtained by converting the sensory characteristic Me into a physical quantity is set.

When the light mode is selected by the occupant operation or the automatic mode, the target steering force characteristic M having the same tendency as that of the exciting mode is set in order to reduce the sense amounts E and J.
When the heavy mode is selected by the occupant operation or the automatic mode, in order to reduce the sensory amount E and increase the sensory amount J, the shape of the steering angle of 30 to 120 ° is made non-linear, and the anti-hissis of the steering angle of 120 ° is obtained. A sensory characteristic Me with increased force is set, and a target steering force characteristic M obtained by converting the sensory characteristic Me into a physical quantity is set.
When the linear mode is selected by the occupant operation or the automatic mode, in order to reduce the sensory quantity I, a sensory characteristic Me is set in which the reaction force of the hysteresis at the steering angle of 30 ° is reduced, and this sensory characteristic Me is converted into a physical quantity. The target steering force characteristic M is set.

  According to the power steering apparatus 1, the sensory amount setting unit 15 that sets a plurality of sensory amounts A to J based on the steering feeling generated by the occupant is provided, and a plurality of sensory amounts set by the sensory amount setting unit 15. Since A1 to J1 are converted into physical quantities Ax to Jx of a plurality of characteristic elements to set the target steering force characteristic M, the occupant's steering feeling can be adjusted using the sense of operation of the steering wheel 2 by the occupant, The occupant's sensation can be actively guided to feel a specific steering feeling.

  The sensory amount setting unit 15 sets the plurality of sensory amounts A1 to J1 based on the equations (1) to (4) of the steering feeling and the plurality of sensory amounts A to J. ) Can be used to easily set a plurality of sensory amounts A1 to J1.

Since the sense amount setting unit 15 determines the steering feeling using the traveling state of the vehicle V, it is possible to adjust the steering feeling according to an external factor that affects the occupant's feeling.
Since the steering force characteristic setting unit 16 converts the plurality of sensory quantities A1 to J1 into a plurality of characteristic elements Ax to Jx that are physical quantities using the equation (5), the plurality of sensory quantities A1 to J1 are converted into physical quantities in the running characteristics. The target steering force characteristic M can be set by quantification.

  The steering force characteristic setting unit 16 adjusts the steering feeling in a region where the force of one hand of the occupant is larger than the other in order to increase or decrease the assist force at least in the range of the steering angle from 30 ° to 120 °. The steering feeling can be efficiently guided.

Next, a modified example in which the embodiment is partially changed will be described.
1) In the above embodiment, an example has been described in which a specific mode is selected from four modes (steering feeling) for the occupant's sensation. It is also possible to set a specific mode from among five or more modes.
Also, an example has been described in which the occupant's sensation is guided to a single mode, but if the same amount of sensation is not adjusted in the opposite direction, the feeling of excitement and lightness will be improved, or the feeling of excitement and linear feeling will be improved. It is also possible to execute a plurality of modes at the same time, such as

2) In the above embodiment, the example in which the sensory amount is adjusted for the sensory amount having the absolute value of the weighting coefficient of 0.2 or more has been described. However, the threshold value of the absolute value of the weighting coefficient is changed depending on the vehicle specifications. Also good. In the exciting mode, when there is no sense amount of the weighting factor larger than the threshold value, two items of the next largest amount of weighting factor are selected, but only one item or three items can be selected. It is.

3) In the above-described embodiment, an example of the direct drive system in which the steering mechanism is directly driven by the electric motor has been described. However, by driving the hydraulic pump by the electric motor, the hydraulic pressure generated by the hydraulic pump is used for the steering mechanism. An indirect driving method that applies assist force may be used.

4) In addition, those skilled in the art can implement the present invention with various modifications added without departing from the spirit of the present invention, and the present invention includes such modifications. is there.

V Vehicle M Target steering force characteristic map A to J Sensory amount Ax to Jx Characteristic element A1 to J1 Sensory amount 1 Power steering device 2 Steering wheel 8 Electric motor 10 Control unit 15 Sensory amount setting unit 16 Steering force characteristic joint bottom 21 Torque sensor 22 Steering angle sensor

Claims (5)

In a power steering apparatus for a vehicle that assists steering of a steering wheel by assist means,
A steering angle sensor for detecting the steering angle;
A torque sensor for detecting steering torque;
A control means for controlling the assist force of the assist means so as to achieve a target steering force characteristic defined by a plurality of characteristic elements;
The control means is
A sensory amount setting means for setting a plurality of sensory amounts corresponding to the plurality of characteristic elements, which are estimated to be generated in the passenger, based on a steering feeling generated in the passenger;
Steering force characteristic setting means for setting the target steering force characteristic by converting a plurality of sensory quantities set by the sensory quantity setting means into physical quantities of the plurality of characteristic elements;
A vehicle power steering apparatus comprising:   2. The power steering apparatus for a vehicle according to claim 1, wherein the sense amount setting means sets the plurality of sense amounts based on a relational expression between the steering feeling and the plurality of sense amounts.   The power steering device for a vehicle according to claim 1 or 2, wherein the sensory amount setting means determines the steering feeling using a running state of the vehicle.   The power of the vehicle according to any one of claims 1 to 3, wherein the steering force characteristic setting means converts the plurality of sensory quantities into physical quantities of the plurality of characteristic elements using Fechner's law. Steering device. The power steering apparatus for a vehicle according to any one of claims 1 to 4, wherein the steering force characteristic setting means increases or decreases the assist force at least in a range of a steering angle of 30 ° to 120 °.