JPH06255512A - Steering force controller - Google Patents

Abstract

PURPOSE:To increase steering reaction force if a driver steers a vehicle erroneously. CONSTITUTION:Running stability of a vehicle becomes worse if a driver steers a steering wheel in the direction in which absolute value of steering angle increases when the vehicle is in the excessive understeer condition. Consequently, when the ratio of target yawing rate to an actual yawing rate is above 1.8 at step 11 and steering judgement amount is positive at S16, reaction force torque which is determined by a yawing rate deviation differential amount and car speed is generated at S17. Erroneous steering becomes difficult due to an increase of steering reaction force, and reduction of running stability is avoided. Also, if the vehicle is in the excessive oversteer condition, steering reaction force does not increase even if an absolute value of steering angle increases, and the operation in which a driver spins the vehicle intentionally is not interrupted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering force control device, and more particularly to a control device for a steering reaction force generation device, that is, a steering reaction force which is opposite to the steering force applied to a steering wheel. The present invention relates to a device for controlling a steering reaction force generation device.

[0002]

2. Description of the Related Art A steering force control device of this type is known, for example, from Japanese Patent Application Laid-Open No. 4-362475. This steering force control device includes (a) a steering angle detection device that detects the steering angle of the steering wheel, and (b) the vehicle is in a cornering limit state and the absolute value of the steering angle detected by the steering angle detection device. And a steering reaction force increasing means for increasing the steering reaction force of the steering reaction force generation device. According to this conventional steering force control device, the steering reaction force can be increased if the absolute value of the steering angle increases, whether the vehicle is in an excessive understeer state or in an excessive oversteer state.

[0003]

Therefore, there is a problem that the steering reaction force may be increased against the driver's intention. A trained driver may intentionally steer the vehicle to spin it, in which case the absolute value of the steering angle may be further increased from the excessive oversteer condition. Is increased, which makes it difficult to intentionally generate spin. On the other hand, when the vehicle is in an excessive understeer state, steering is performed so that the absolute value of the steering angle increases, because the driver is inexperienced and intentionally spins. It is usually not. In such a case, the driver increases the absolute value of the steering angle in order to bring the vehicle closer to the driver's target arrival point. As a result, the understeer state further progresses, or the side slip of the rear wheels increases and, conversely, the state becomes an excessive oversteer state, so that the vehicle reaches a more unstable state. In the latter case, it is necessary to increase the steering reaction force, but in the former case, it is better not to increase it. In view of the above circumstances, the present invention has an object to obtain a steering reaction force control device capable of increasing the steering reaction force only when the driver makes an incorrect steering.

[0004]

[Means for Solving the Problems]
As shown in FIG. 1, the steering force control device includes: (a) the steering angle detection device 1, (c) the actual yaw rate detection device 2 for detecting the actual yaw rate of the vehicle, and (d) the steering angle control device. The ratio of the target yaw rate determined based on the steering angle detected by the angle detection device 1 to the actual yaw rate detected by the actual yaw rate detection device 2 is greater than or equal to a set value greater than 1 and is detected by the steering angle detection device 1. The steering reaction force increasing means 4 for increasing the steering reaction force of the steering reaction force generation device 3 when the absolute value of the steering angle increases.

[0005]

In the steering force control device of the present invention, when the ratio of the target yaw rate to the actual yaw rate is equal to or greater than the set value greater than 1 and the absolute value of the steering angle of the steering wheel increases, the steering reaction force increases. To be made. The target yaw rate is determined based on the steering angle of the steering wheel detected by the steering angle detection means, and the actual yaw rate is detected by the actual yaw rate detection means.
The steering reaction force is a controllable force that is opposite to the steering force applied to the steering wheel, is generated by the steering reaction force generation device, and is increased by the steering reaction force increasing means. When the steering reaction force is increased, the steering wheel becomes heavy, and it becomes difficult for the driver to increase the absolute value of the steering angle.

The ratio of target yaw rate to actual yaw rate is approximately 1 when the vehicle is in a steady state. This is because the actual yaw rate and the target yaw rate substantially match. However, if the vehicle is understeered,
The actual yaw rate becomes smaller than the target yaw rate, and the above ratio becomes greater than 1. The magnitude of this ratio increases as the understeer state progresses.

When obtaining the ratio of the target yaw rate to the actual yaw rate, the actual yaw rate becomes the denominator. Therefore, when the absolute values of the target yaw rate and the actual yaw rate are very small, the above ratio becomes extremely large due to an error, and although it is actually almost straight, it is erroneously considered to be an excessive understeer state. There is a possibility that it will be. In order to avoid it, it is desirable to exclude the case where the absolute value of the actual yaw rate is very small. In this case, the vehicle is considered to be in a straight-ahead state, so there is no problem in excluding it.

When the vehicle is excessively understeered,
The steering wheel may be steered in the direction in which the absolute value of the steering angle increases. The reason why the driver does not travel along the intended course of the vehicle is that he / she mistakenly thinks that the steering angle is insufficient and that the absolute value of the steering angle is increased. However, it is better not to perform such steering. In the case of an excessive understeer state, it is better to steer the steering wheel so that the target yaw rate approaches the actual yaw rate and the absolute value of the steering angle decreases. The “set value greater than 1” in the claims is the magnitude of the ratio of the target yaw rate to the actual yaw rate when the vehicle is at the lower limit of the excessive understeer state.

[0009]

As described above, according to the steering force control device of the present invention, when the vehicle is in an excessive understeer state, the driver makes an erroneous steering operation to increase the absolute value of the steering angle of the steering wheel. It becomes difficult for the vehicle to come off, and the deterioration of the running stability of the vehicle is avoided. Further, when the vehicle is in an excessive oversteer state, the absolute value of the steering angle of the steering wheel is increased because the driver intentionally performed the steering, not the incorrect steering. The steering reaction force is not increased.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which a steering reaction force control device according to an embodiment of the present invention is applied to an electric power steering device will be described in detail with reference to the drawings. In FIG. 2, 10 and 12 are left front wheels and right front wheels as steering wheels.
Reference numeral 12 is connected by a steering gear device 18 via a knuckle arm 14 and a tie rod 16. The steering gear device 18 includes the steering gear box 2
0, a rack 22, a pinion 24, etc., and the rack 22 is provided slidably with respect to the steering gear box 20. Tie rods 1 on both ends of the rack 22
A steering wheel 28 is attached to the pinion 24 via a steering shaft 26. Further, a speed reducer 30 is attached to an intermediate portion of the steering shaft 26, and an electric motor 32 is connected to the speed reducer 30. A motor control device 36 is connected to the electric motor 32 via a drive circuit 34, and a current controlled by the motor control device 36 is supplied to the electric motor 32.

When steering force is applied to the steering wheel 28, steering torque is applied to the steering shaft 26. The pinion 24 is rotated, whereby the rack 22 is slid with respect to the steering gear box 20, and the tie rod 16 and the knuckle arm 14 are rotated.
The left and right front wheels 10 and 12 are steered via the. When electric current is supplied to the electric motor 32, control torque is applied to the steering shaft 26. That is, the steering shaft 26 is provided with both the steering torque due to the steering force applied to the steering wheel 28 and the control torque provided by the electric motor 32.

The motor control device 36 is mainly composed of a computer, and has a steering angle sensor 40,
A wheel speed sensor 42, a yaw rate sensor 44, etc. are connected, and an electric motor 32 is connected to an output section via a drive circuit 34.
Are connected. In the ROM, a table shown in the graphs of FIGS. 3 and 4 and a reaction force torque determination program, a normal control torque determination program, a road surface μ calculation program, a vehicle speed, acceleration, etc. calculation shown in the flowchart of FIG. 5 described later are calculated. Stores programs, etc.

The steering angle sensor 40 detects the rotation angle of the steering wheel 28, and indicates the distance from the neutral position of the steering wheel 28. The positive value is the distance to the left from the neutral position. Further, the target yaw rate γ * is calculated based on the steering angle of the steering wheel 28. The target yaw rate γ * and the steering angle θ of the steering wheel 28 have a relationship represented by the following equation. γ * (s) / θ (s) = G (s) ・ {1 / (N ・ L)} {V /
(1 + kh · V ² )} where G (s) = 1 / (1 + Tv · s), N is the steer gear ratio, L is the wheel base, kh is the stability factor, and Tv is the target yaw rate vehicle speed sensitive first-order lag time constant. Respectively. The target yaw rate vehicle speed sensitive first-order lag time constant Tv is a value that is increased according to an increase in the vehicle speed V, and the time constant Tv and the vehicle speed V have the relationship shown in the table of FIG.

The wheel speed sensor 42 detects the number of rotations of each wheel, and the vehicle speed V, the road surface μ and the like are obtained based on these output values. The road surface μ is obtained by comparing the rotational speeds of the front wheels 10 and 12 (driven wheels) during driving with the rotational speeds of rear wheels (driving wheels) not shown. The difference between the rotational speed of the rear wheels and the rotational speed of the front wheels 10 and 12 is larger when the road surface μ is lower than when the road surface μ is high. The yaw rate sensor 44 detects the angular velocity of rotation of the vehicle about the vertical axis, and the leftward rotation is positive.

The operation of the electric power steering system constructed as above will be described. The current i supplied to the electric motor 32 has a target torque τ as shown in FIG.
Controlled to get req. Target torque τreq
Is the sum of the normal control torque τnml and the reaction force torque τcnt, and the normal control torque τnml and the reaction force torque τcnt are determined based on a program stored in the motor control device 36 as described later. The target torque τreq is converted into a current i by the torque current change gain Kτi, and is supplied to the electric motor 32 having a transfer function of M (s). On the other hand, the output torque τout of the electric motor 32 is fed back,
The difference between the output torque τout and the target torque τreq is converted into the current i ′ by the feedback compensation transfer function H (s). The sum of the current i and the current i ′ is supplied to the electric motor 32. In this way, the supply current to the electric motor 32 is controlled so that the output torque τout close to the target torque τreq is obtained.

The normal control torque τ nml is obtained based on a program stored in the ROM of the motor control device 36. The normal control torque τ nml is obtained based on the vehicle speed V, the steering angle θ of the steering wheel 28, etc., and is decreased with the increase of the vehicle speed V and increased with the increase of the steering angle θ.

The reaction force torque τcnt is obtained based on the program shown in the flowchart of FIG. The reaction torque τcnt is always 0, but the vehicle is in an excessive understeer state and the steering wheel 28
It is increased from 0 when the absolute value of the steering angle θ is increased. The determination as to whether the vehicle is in an excessive understeer state is made based on the ratio δ = γ * / γ (1) of the target yaw rate γ * to the actual yaw γ. If the ratio δ is equal to or greater than the set value (1.8 in this embodiment), the vehicle is considered to be in an excessive understeer state. Steering wheel 2
The determination of whether or not the absolute value of the steering angle θ of 8 is increased is made based on the steering determination amount Δγb Δγb = γ · (γ * −γ) ′ (2). When the steering determination amount Δγb is larger than 0, it is considered that the absolute value of the steering angle θ has been increased.

First, the former ratio δ will be described. The ratio δ of the target yaw rate γ * to the actual yaw rate γ is
The value is close to 1 when the vehicle is in a normal traveling state.
This is because the actual yaw rate γ and the target yaw rate γ * substantially match. However, when the vehicle is not in the normal traveling state, the deviation amount from 1 becomes large. For example, when the tire is in the non-linear region, the target yaw rate γ * and the actual yaw rate γ do not match due to insufficient cornering force. Then, when the vehicle is in an excessive understeer state, the actual yaw rate γ becomes too small with respect to the target yaw rate γ *, so the ratio Δ becomes larger than the set value.

It is also conceivable to detect that the vehicle is in an excessive understeer state on the basis of the difference between the target yaw rate γ * and the actual yaw rate γ. However, even if the difference is the same, the traveling state of the vehicle may be different. For example, when the vehicle is in an excessive understeer state and the difference between the actual yaw rate γ is 0.5 (rad / s) is 0.4, the vehicle is in a normal running state, and the actual yaw rate γ is 1.0. When the difference is 0.4 with respect to (rad / s), the difference is the same and small, so that in any case, the vehicle is considered to be in the normal running state.

On the other hand, when the detection is performed based on the ratio of the target yaw rate γ * to the actual yaw rate γ as in the present embodiment, the ratio is the same and the running state of the vehicle is not significantly different. For example, in the above two cases, the ratio is 1.8 in the former case, which means that the vehicle is in an excessive understeer state, and in the latter case, the ratio is 1.4, which indicates that the vehicle is running normally. Although it is said that the vehicle is in a state, these detection results match the actual vehicle state. Moreover, since it is a division, there is an advantage that it is not necessary to consider the generation direction of the yaw rate.

On the other hand, since it is division, it is desirable to exclude it when the size of the denominator (the absolute value of the actual yaw rate γ) is very small. This is because when the absolute value of the actual yaw rate γ is extremely small, the ratio may increase due to an error. In this case, there is no problem even if the vehicle is excluded because the vehicle is almost straight ahead.

In this embodiment, as shown in FIG.
When the absolute value | γ | of the actual yaw rate γ is smaller than the threshold value γ _min, it is excluded. Threshold γ
_min is _calculated by the following formula. γ _min = k · μGy / V where k is a positive coefficient less than 1 and is 0.1 in this embodiment. Further, μGy is the limit lateral G, and is a value that increases as the road surface μ increases. Limit side G
The relationship between (μGy) and the road surface μ is predetermined, and the table is stored in the ROM of the motor control device 36. The threshold value γ _min increases as the road surface μ increases and decreases as the vehicle speed V increases. When the road surface μ is low or the vehicle speed V is high, the threshold value γ _min is reduced because the vehicle easily reaches the limit state, and when the road surface μ is high or the vehicle speed V is low, it is difficult to reach the limit state. Therefore, the threshold value γ _min is increased. As is clear from the above description, when the target yaw rate γ * and the actual yaw rate γ belong to the shaded area shown in FIG. 7, it is detected that the vehicle is in an excessive understeer state.

Next, the detection of whether or not the absolute value of the steering angle θ of the steering wheel 28 has been increased will be described. As shown in the equation (2), the steering determination amount Δ
γb is the actual yaw rate γ and the yaw rate deviation differential amount (γ *
−γ) ′. Yaw rate deviation derivative (γ *-
γ) ′ is the amount of change in the value obtained by subtracting the actual yaw rate γ from the target yaw rate γ *. No disturbance, vehicle speed V, steering angle θ
Etc. are constant, the yaw rate deviation differential amount (γ * −
γ) ′ is 0. This is because both the target yaw rate γ * and the actual yaw rate γ are constant. On the other hand, when the steering angle θ changes when the vehicle is in an excessive understeer state, the target yaw rate γ * changes accordingly, but the actual yaw rate γ hardly changes or its change amount is small. Therefore, the yaw rate deviation differential amount (γ * −γ) ′ changes as the steering angle θ changes.

When the vehicle is turning left (when the steering angle θ and the actual yaw rate γ are positive) and the vehicle is in an excessive understeer state, the driver operates the steering wheel 2
When 8 is further steered to the left, the target yaw rate γ * increases accordingly, but the actual yaw rate γ does not increase, or even if it increases, the increase amount is small. It may decrease in some cases. Therefore, the difference between the target yaw rate γ * and the actual yaw rate γ becomes large, and the yaw rate deviation differential amount (γ * −γ) ′ becomes positive. Further, since the actual yaw rate γ is positive (turning left), the steering determination amount Δγb is positive. On the other hand, when the driver steers the steering wheel 28 to the right, the difference becomes small and the yaw rate deviation differential amount (γ * −γ) ′ becomes negative. On the other hand, the actual yaw rate γ
Is positive, the steering determination amount Δγb becomes negative.

Similarly, when the vehicle is turning right (when the steering angle θ and the actual yaw rate γ are negative) and the vehicle is in an excessive understeer state, the driver steers the steering wheel 28 further to the right. Then, the difference between the target yaw rate γ * and the actual yaw rate γ becomes small (the absolute value becomes large). Therefore, the yaw rate deviation differential amount (γ
* -Γ) 'becomes negative, and the actual yaw rate γ is also negative (turn right)
Therefore, the steering determination amount Δγb becomes positive. As described above, when the absolute value of the steering angle θ is increased when the vehicle is in the excessive understeer state,
The steering determination amount Δγb becomes positive. The vehicle speed V,
The steering determination amount Δγb is also positive when the steering angle θ is constant and the actual yaw rate γ decreases due to disturbance or the like, or when the steering angle θ is constant and the vehicle speed V increases. Since the traveling state of the vehicle in these cases is substantially the same as the state when the absolute value of the steering angle θ is increased, the steering force may be controlled in these cases.

The reaction torque τcnt is increased when the ratio δ is equal to or greater than the set value (1.8 in this embodiment) and the steering determination amount Δγb is positive.

If the steering wheel 28 is operated to reduce the absolute value of the steering angle when the vehicle is in an excessive understeer state, the cornering force with respect to the sideslip angle is reduced, so that the running stability of the vehicle is reduced. Will increase. In contrast, the steering wheel 28
Is operated so that the absolute value of the steering angle θ increases, the understeer condition progresses further, or the side slip of the rear wheels increases and conversely the condition becomes excessive oversteer. descend. This steering is performed when the driver misunderstands the shortage of the actual yaw rate γ with respect to the target yaw rate γ * as the shortage of the steering angle θ. Therefore, if the steering wheel 28 is steered in a direction in which the absolute value of the steering angle θ increases when the vehicle is in an excessively understeer state, it is difficult to make an erroneous steering operation, and the running stability of the vehicle deteriorates. Is avoided. It also has the effect of making the driver aware that the steering that the driver is actually trying to perform is not desirable.

In this embodiment, the reaction torque τcnt is
As shown in the following equation, the yaw rate deviation differential amount (γ * −
γ) ′ and the vehicle speed V. [tau] cnt = -F (V) * ([gamma] *-[gamma]) '(3) F (V) is a vehicle speed sensitive gain, which is a value that increases as the vehicle speed V increases. The relationship between the vehicle speed sensitive gain F (V) and the vehicle speed V is a table represented by the graph of FIG. Also, the yaw rate deviation differential amount (γ * −γ) ′
Is the amount corresponding to the amount of change in the steering angle θ as described above, in other words, the steering angle θ of the steering wheel 28.
Is an amount corresponding to the difference between the vehicle traveling state when the absolute value of is increased (when the steering is erroneous) and the vehicle traveling state when the correct steering is performed. The reaction torque τcnt increases as the amount of driver's incorrect steering increases,
The larger the vehicle speed V, the larger the vehicle speed.

The reaction torque determination routine for determining the reaction torque τcnt will be described below with reference to the flowchart of FIG. In step 1 (hereinafter simply referred to as S1. The same applies to other steps), the steering angle θ (i), the vehicle speed V (i), the yaw rate γ (i), and the road surface μ (i) are read, and in step S2. The threshold γ _min is calculated. In S3, it is determined whether the absolute value of the yaw rate γ (i) is smaller than the threshold value γ _min . Threshold γ
If it is smaller than _min and YES is determined, the flag described later is reset in S4, and the reaction torque τcnt is set to 0 in S5. In S6, the reaction force torque τcnt value is output, and in S7, each data read this time becomes the previous value, and the execution of one routine ends. As a result, the normal control torque τnml is directly used as the target torque τreq, and the electric motor 32 is supplied with a current such that the output torque τout matches the target torque τreq.

On the other hand, if the absolute value of the yaw rate γ (i) is greater than or equal to the threshold value γ _min and NO is determined in S3, S
In 8 and 9, the target yaw rate γ * and the ratio δ are calculated, and it is determined in S10 whether or not the flag is set. When S10 is executed for the first time, the flag is not set, so NO is determined. next,
In S11, it is determined whether the ratio δ is equal to or greater than the set value (1.8 in this embodiment). If the vehicle is not in an excessive understeer state, NO is determined and S
4 and subsequent steps are executed. If the vehicle is in an excessive understeer state, YES is determined and the flag is set in S12. That is, the flag indicates that the vehicle is in an excessive understeer state. Then, in S13, the reaction torque τcnt is set to 0, and S
6 and subsequent steps are executed.

After the flag F is set, YES is determined in S10. In S14 and S15, it is determined whether or not the end condition is satisfied. If not satisfied, S16 and subsequent steps are executed, but if satisfied, S19 and subsequent steps are executed. The termination condition will be described later. If S14 and S15 are executed immediately after it is detected that the vehicle is in an excessive understeer state,
Since the termination condition is not satisfied, NO is determined in any step.

At S16, it is determined whether the steering determination amount Δγb is positive. The steering determination amount Δγb is as follows.
It is obtained by dividing the difference between the current value and the previous value of the target yaw rate γ * minus the actual yaw rate γ by the cycle time Δt. Δγ b = γ (i) ・ {(γ * (i) −γ (i)) − (γ * (i-1) −
γ (i-1))} / Δt Here, the cycle time Δt is the time required to execute this routine once. As described above, YES is determined if the steering wheel 28 is steered in the direction in which the absolute value of the steering angle θ increases, and the reaction torque τcnt is obtained in S17. The electric motor 32 is supplied with a current according to the increase of the reaction torque τcnt, and it is difficult to increase the steering wheel 28. N when the absolute value of the steering angle is reduced or kept constant
O is determined, and the reaction torque τcnt is 0 in S18.
It is said that

Whether or not the above-mentioned termination condition is satisfied is judged at S14 as to whether or not the state where the ratio δ is close to 1 has continued for a certain period of time, or at S15 the absolute value of the actual yaw rate γ is threshold. This is performed by determining whether the state smaller than the value γ _min has continued for a certain period of time. The fact that the ratio δ is approximately 1 means that the vehicle is in a normal running state, and that the absolute value of the actual yaw rate γ is smaller than the threshold value γ _min means that the vehicle is almost in a straight traveling state. Is represented. Therefore, S14,15
In either one of the steps, YES is determined when the state in which the running stability of the vehicle is not likely to deteriorate is continued for a certain period of time, the flag is reset in S19 and S20, and the reaction torque τcnt Is set to 0.

As described above, according to the steering force control device of the present invention, the reaction torque τcnt is increased when the driver makes an incorrect steering while the vehicle is in an excessive understeer state. . This makes it difficult for the driver to make an erroneous steering operation that increases the absolute value of the steering angle of the steering wheel, and avoids a reduction in the running stability of the vehicle. In addition, when the absolute value of the steering angle of the steering wheel is increased when the vehicle is in the oversteer state, it is assumed that the driver did not intentionally steer the steering wheel, but rather intentionally performed the reaction torque. τcnt cannot be increased.

Further, since it is detected that the vehicle is in the excessive understeer state based on the ratio δ of the target yaw rate γ * to the actual yaw rate γ, it is accurately detected that the vehicle is in the excessive understeer state. Further, since the reaction force torque τcnt is determined based on the yaw rate deviation differential amount, the steering reaction force can be increased according to the amount of erroneous steering by the driver.

In the above embodiment, the reaction torque τcnt is always set to 0 and generated only when necessary (increased from 0), but it is always supplied and required. In some cases, the number may be increased. Further, the reaction force torque τcnt is not necessarily determined based on the yaw rate deviation change amount and the vehicle speed V, but may be determined based on other amounts such as the steering angle change amount. For example, if a constant value is always added to the reaction force torque τcnt, [τcnt = -F (V) · (γ *-
γ) ′ + A], the steering reaction force is suddenly increased when the absolute value of the steering angle of the steering wheel 28 is increased. This enables the driver to be informed well.

Further, in the above embodiment, the steering reaction force is increased when the steering determination amount Δγb is positive, but steering is performed when the yaw rate deviation Δγ (γ = γ * -γ) is positive. The reaction force may be increased.
In this case, not only is it difficult to steer the steering wheel 28 in the direction for turning the steering wheel 28, but there is an advantage that the steering wheel 28 can be easily steered in the direction for turning the steering wheel back.

Further, the threshold value γ _min may be a constant value or may be determined based on only the vehicle speed V and only the road surface μ. Further, the setting value of the ratio δ is not limited to the above embodiment as long as it is a value larger than 1.

Further, the steering force control device of this embodiment can be applied to a hydraulic power steering device. Although not exemplarily illustrated, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of drawings]

FIG. 1 is a block diagram conceptually showing the structure of the present invention.

FIG. 2 is a circuit diagram of an electric power steering device including a steering force control device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a vehicle speed and a time constant stored in a ROM of the motor control device of the above embodiment.

FIG. 4 is a diagram showing a relationship between a vehicle speed sensitive gain stored in a ROM of the motor control device and a vehicle speed.

FIG. 5 is a flowchart showing a reaction force torque τcnt determination program stored in a ROM of the motor control device.

FIG. 6 is a block diagram for explaining control of the electric motor.

FIG. 7 is a diagram showing a relationship between a target yaw rate γ * and an actual yaw rate γ.

[Explanation of symbols]

 18 Steering Gear Device 28 Steering Wheel 32 Electric Motor 34 Drive Circuit 36 Motor Control Device 40 Steering Angle Sensor 44 Yaw Rate Sensor

Claims (1)

[Claims] 1. A control device for controlling a steering reaction force generation device which is provided between a steering wheel and a steering wheel and generates a controllable steering reaction force in a direction opposite to a steering force applied to the steering wheel. A steering angle detection device for detecting a steering angle of the steering wheel, an actual yaw rate detection device for detecting an actual yaw rate which is an actual yaw rate of the vehicle, and a steering angle detected by the steering angle detection device. When the ratio of the target yaw rate to the actual yaw rate detected by the actual yaw rate detection device is equal to or greater than a set value greater than 1, and the absolute value of the steering angle detected by the steering angle detection device increases, A steering force control device comprising: a steering reaction force increasing means for increasing the steering reaction force of the steering reaction force generation device.