JP2001106107A - Power steering control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power steering control device for restraining a steering assist force from abruptly varying when an engine is automatically stopped or started in a steered condition. SOLUTION: At step 113, in view of a set fmode, which one of a normal control mode, an automatic engine stop mode and an engine restart mode is set is determined. If it is determined as the automatic engine stop mode (fmode=1, 2), at step 114, the motor current is gradually deceased in association with the automatic engine stop. Further, if it is determined as the engine restart mode (fmode=3, 4), at step 115, the motor current is gradually increased in association with the engine restart. Meanwhile, it is determined as the normal control mode (fmode=0), at step 116, normal power steering control is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering control device mounted on a vehicle having an automatic engine control device for automatically stopping or starting an engine.

[0002]

2. Description of the Related Art Conventionally, when a vehicle stops at an intersection while traveling in a city, the engine is stopped under predetermined stop conditions, and then the engine is started under predetermined start conditions, thereby saving fuel and reducing exhaust gas. There is known an automatic engine control device for reducing the engine speed.
No. 3415, and the like.

[0003] On the other hand, there is also known a power steering device for applying an auxiliary steering force to a steering by hydraulic pressure or electric power.

[0004]

Here, in the above-mentioned power steering apparatus, when the engine is automatically stopped, the auxiliary steering force is released. When a control device is mounted, there are the following problems.

That is, there is a case where the engine is automatically stopped in a state where the steering wheel is steered at an intersection or the like when traveling in a city. In this case, the auxiliary steering force is suddenly lost due to the stop of the engine, and the steering wheel will return to the neutral position. As a result, the driver may feel uncomfortable.

[0006] When the engine is automatically started while the steering is being operated, an auxiliary steering force is suddenly generated, which may give the driver an uncomfortable feeling.

Accordingly, the present invention relates to a power steering control device mounted on a vehicle having an engine automatic control device for automatically stopping or starting the engine, wherein the engine is automatically stopped or started when the steering is in a steering state. It is another object of the present invention to provide a power steering control device which does not give a driver an uncomfortable feeling.

[0008]

According to the first aspect of the present invention, when the engine of the vehicle is automatically stopped or restarted, the auxiliary steering force adjusting means is used. Suppress sudden changes in auxiliary steering force applied to the steering.

That is, when the engine is automatically stopped in the steering state, the auxiliary steering force applied to the steering is adjusted so that it does not suddenly decrease. When the engine is automatically restarted, the steering is stopped. By adjusting the applied auxiliary steering force so that it does not suddenly increase,
It is possible to suppress a sudden change in the auxiliary steering force that gives the driver a sense of discomfort.

According to the second aspect of the present invention, there is provided an auxiliary steering force adjusting means in response to a control signal relating to automatic stop or restart of an engine. Suppress sudden changes in auxiliary steering force applied to the steering.

That is, when a control signal relating to the automatic stop of the engine is input in the steering state, the auxiliary steering force applied to the steering is adjusted so as not to be suddenly reduced, or the automatic engine stop is performed. When the control signal relating to the restart is input, the auxiliary steering force applied to the steering is adjusted so that it does not suddenly increase, whereby it is possible to suppress a sudden change in the auxiliary steering force that gives the driver an uncomfortable feeling.

According to the third aspect of the invention, when the auxiliary steering force to be applied to the steering is given by the driving force of the electric motor, the driving force of the electric motor is controlled by the auxiliary steering force adjusting means. .

That is, when the engine is automatically stopped, the driving force of the electric motor is adjusted so as not to suddenly decrease, or when the engine is restarted, the driving force of the electric motor does not suddenly increase. By adjusting
The same effects as those of the first and second aspects are obtained.

Further, in this case, since the adjustment of the auxiliary steering force is performed by controlling the driving force of the electric motor, the control characteristic when the driving force is reduced or increased, for example, when the sudden change of the auxiliary steering force is suppressed, is easily improved. Can be set to

It is desirable that the driving force of the electric motor be gradually reduced when the engine of the vehicle is automatically stopped.

Further, as in the invention according to claim 5,
When the vehicle engine is automatically restarted, it is desirable to gradually increase the driving force of the electric motor.

According to the sixth aspect of the invention, when the auxiliary steering force to be applied to the steering is applied by the pressure of the working fluid supplied from the hydraulic pump, the auxiliary steering force adjusting means is operated to the hydraulic pump. It consists of a check valve that prevents the fluid from flowing back.

That is, when the engine is automatically stopped, the working fluid flows back to the hydraulic pump, so that the auxiliary steering force applied to the steering is suddenly reduced. A sudden decrease in force can be suppressed.

According to the seventh aspect of the invention, when the auxiliary steering force applied to the steering is applied by the pressure of the working fluid supplied from the hydraulic pump, the auxiliary steering force adjusting means is provided with the working fluid. From the pressure accumulating means.

That is, when the engine restarts automatically,
By absorbing the pressure of the working fluid supplied from the hydraulic pump by the pressure accumulating means, the auxiliary steering force applied to the steering can be gradually increased, and a sudden increase in the auxiliary steering force can be suppressed.

According to the present invention, when the auxiliary steering force applied to the steering is given by the pressure of the working fluid supplied from the hydraulic pump,
The auxiliary steering force adjusting means is constituted by a pressure regulating valve for adjusting the pressure of the working fluid.

That is, when the engine is automatically stopped by the pressure regulating valve, the pressure of the working fluid is adjusted so that the auxiliary steering force applied to the steering does not suddenly decrease. By adjusting the pressure of the working fluid so that the auxiliary steering force applied to the vehicle does not suddenly increase, it is possible to suppress a sudden change in the auxiliary steering force.

According to the ninth aspect of the present invention, the determining means determines whether or not a predetermined time has elapsed since the engine was automatically stopped, and the determining means has determined that the predetermined time has elapsed. When it is determined that there is no sudden change in the auxiliary steering force, a process is executed.

Thus, instead of executing the processing for suppressing the sudden change in the auxiliary steering force immediately after the engine is automatically stopped, the auxiliary steering force when the engine is automatically stopped until a predetermined time elapses. In order to execute processing to maintain and suppress a sudden change in the auxiliary steering force after a predetermined time has elapsed,
It becomes more in line with the driver's feeling.

According to the tenth aspect of the present invention,
By making the predetermined time variable based on at least one of the remaining amount of the battery of the vehicle and the driving state of the auxiliary device disposed in the vehicle, for example, when the remaining amount of the battery is low or the auxiliary device is driven. When the engine is stopped, it is possible to execute processing to suppress sudden changes in the auxiliary steering force immediately after the automatic stop of the engine,
Electricity can be saved as much as the time for maintaining the auxiliary steering force is reduced.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power steering control device mounted on a vehicle equipped with an automatic engine control device according to the present invention will be described below with reference to the drawings.

[First Embodiment] In the first embodiment,
As a power steering control device, an electric power steering control device that adjusts an auxiliary steering force applied to a steering by an electric motor will be described.

FIG. 1 is a block diagram showing a control system according to this embodiment.

As shown in FIG. 1, an engine automatic control ECU 1 for executing a known engine automatic control for automatically stopping and starting the engine when a predetermined condition is satisfied,
An electric motor 5 for applying an auxiliary steering force to a steering wheel (not shown) via a steering gear 6 and a control signal indicating the operating state of the engine (automatic stop and restart) are input from the engine automatic control ECU 1 and , A target motor current Im for driving the electric motor 5
And an electric power steering ECU 2 that computes the following.

The power steering gear 6 is provided with a torque sensor 7 for detecting a steering torque. A steering torque signal detected by the torque sensor 7 is input to the electric power steering ECU 2.

Also, the above-mentioned electric power steering ECU
2, a vehicle speed signal from a vehicle speed sensor 3, a temperature signal from a motor temperature sensor 4 for detecting the temperature of the electric motor 5, and a motor rotation angle signal from the electric motor 5 are input.

The electric power steering E
The CU 2 calculates a target motor current Im for driving the electric motor 5 based on the input control signal indicating the operation state of the engine, a steering torque signal, a vehicle speed signal, a temperature signal, and a motor rotation angle signal. At the same time, a drive current I for driving the electric motor 5 is obtained from the target motor current Im and the actual motor current Ir fed back from the electric motor 5.

Next, the processing executed by the electric power steering control device configured as described above will be described.

FIG. 2 shows an electric power steering ECU 2
2 shows a control algorithm executed by the control unit.

First, in step 101, a steering torque signal input from the torque sensor 7 is read, and in subsequent step 102, predetermined signal processing is performed on the read steering torque signal. Specifically, a process of compensating for a phase delay of the steering gear 6 with respect to the driver's operation of the steering wheel based on an arithmetic expression stored in the electric power steering ECU 2 is executed.

In the following step 103, step 102
The basic assist torque Ta, which is the basis of the auxiliary steering force applied to the steering, is calculated in accordance with the steering torque signal subjected to the signal processing. The basic assist torque Ta is calculated by, for example, storing the basic assist torque Ta corresponding to the steering torque signal as shown in FIG. 3 as a map function.

Next, at step 104, the vehicle speed sensor 4
In response to the vehicle speed signal read from the CPU, the basic assist torque Ta calculated in step 103 is corrected, and a vehicle speed sensitive process for obtaining the corrected assist torque Tc is executed. That is, during high-speed running, the basic assist torque Ta
Is corrected to be small so that the driver can sufficiently respond to the operation of the steering wheel. On the other hand, when the vehicle is running at low speed, the basic assist torque Ta is corrected so as to increase, and the steering force is reduced with respect to the driver's steering operation.

Next, at step 105, in order to reduce the resistance felt when the driver starts turning the steering wheel,
The differential value of the steering torque signal subjected to the signal processing in step 102 is calculated, and the inertia compensation torque Ti is calculated based on the differential value.

In step 106, a return compensation torque Tr applied to the power steering gear 6 to return the steering to the neutral position is calculated based on the motor rotation angle signal. The return compensation torque Tr is calculated by, for example, storing the return compensation torque Tr corresponding to the motor rotation angle signal as shown in FIG. 4 as a map function.

Next, at step 107, a damper torque Td for improving the convergence of the steering wheel at the time of return is calculated based on the motor rotation angular speed signal obtained from the differential value of the motor rotation angle signal. This damper torque Td is calculated by, for example, storing the damper torque Td corresponding to the motor rotation angular velocity signal as shown in FIG. 5 as a map function.

In the following step 108, the above step 1
The target motor torque Tm is calculated by taking the sum of the corrected assist torque Tc, the inertia compensation torque Ti, the return compensation torque Tr, and the damper torque Td obtained by the steps 04, 105, 106, and 107. In step 109, a target motor current Im for driving the electric motor 5 is calculated from the target motor torque Tm obtained in step 108.

Next, in step 110, fmode is set to 0.
Is determined. Here, fmode is
This mode is set in accordance with the operation mode of the electric power steering control device, and fmode = 0 represents an operation mode of normal electric power steering control. Note that the initial value of fmode is set to 0. Here, if it is determined that fmode = 0, step 11
At 1, it is determined whether or not the engine is being automatically stopped. This determination is made based on the control signal indicating the operating state of the engine input from the engine automatic control ECU 1 described above. Here, if it is determined that the engine is being stopped automatically, fmode is set to 1 in step 112, and the process proceeds to step 113. This fmode = 1 indicates the standby mode of the motor current gradual decrease process described later.

On the other hand, in step 110, fmode = 0
If not, and if it is determined in step 111 that the engine is not being automatically stopped, step 1
The process proceeds to step 113 without executing step 12.

In the following step 113, according to the set fmode, when fmode is 0, the normal control mode is set, when fmode is 1 or 2, the engine is automatically stopped, and when fmode is 3 or 4, the engine is restarted. Mode is determined. Note that fmode is 2,
Details of the operation modes in cases 3 and 4 will be described later.

Next, in step 113, when it is determined that the normal control mode, that is, fmode = 0,
16 and in the following step 116, the drive current I for driving the electric motor 5 based on the deviation between the target motor current Im calculated in step 109 and the actual motor current Ir fed back from the electric motor 5.
Is calculated.

If it is determined in step 113 that the engine is in the automatic engine stop mode (fmode = 1, 2), the process proceeds to step 114 to execute a motor current gradual reduction process accompanying the automatic engine stop. In step, the drive current I is calculated from the deviation between the corrected target motor current Imm (described in detail later) obtained in step 114 and the actual motor current Ir.

Further, if it is determined in step 113 that the engine is in the engine restart mode (fmode = 3, 4), the routine proceeds to step 115, where a motor current gradual increase process accompanying the engine restart is executed. At 116, the drive current I is calculated from the deviation between the corrected target motor current Imm (to be described in detail later) obtained at step 115 and the actual motor current Ir.

Here, the motor current gradual decrease process of step 114 and the motor current gradual increase process of step 115 correspond to the auxiliary steering force adjusting means of the present invention.

Next, the control algorithm of the motor current gradual reduction process in step 114 will be described with reference to FIG.

First, in step 201, the elapsed time Ts from the automatic stop of the engine is calculated.

In the following step 202, the standby time Tw1 (corresponding to the predetermined time of the present invention) until the motor current gradual decrease process is performed is calculated according to the remaining amount of the battery and the driving state of the electric auxiliary machine (electric compressor or the like). I do. That is, when the remaining amount of the battery is small or when the electric auxiliary machine is driven, the motor current is gradually reduced immediately after the engine is automatically stopped, so that electricity can be saved. However, the standby time Tw1 may be a fixed value or 0.

Next, in step 203, fmode is 1
Is determined. If it is determined that fmode = 1, the process proceeds to step 204, and it is determined whether the elapsed time Ts from the automatic stop of the engine is longer than the standby time Tw1. Here, if the elapsed time Ts from the automatic stop of the engine is longer than the gradual decrease standby time Tw1, fmode is set to 2 in Step 205. Where fmode = 2
Means the execution mode of the motor current gradual decrease process.

In the following step 206, the motor current gradual decrease coefficient λ (t) is calculated when executing the motor current gradual decrease process. This motor current gradual decrease coefficient λ (t) can be obtained by storing as a positive monotone decreasing function of 1.0 or less with respect to time t as shown in FIG. The motor current gradual decrease coefficient λ (t) is adapted according to the driver's feeling.

In step 207, it is determined whether or not there is an engine restart request. This determination is made based on a control signal indicating the operating state of the engine input from the engine automatic control ECU 1. Here, if there is no engine restart request, the final target motor current Imm is calculated in step 209 based on the following equation 1, and the motor current gradual decrease process ends.

[0055]

Imm = λ (t) × Im On the other hand, if it is determined in step 203 that fmode is not 1, the process proceeds to step 206 described above.

If it is determined in step 204 that the elapsed time Ts from the automatic stop of the engine is shorter than the standby time Tw1, the process proceeds to step 209 in which the motor current gradual decrease coefficient λ (t) is set to 1.0 in step 210. .

When an engine restart is requested in step 207, that is, when the brake is released or the accelerator is depressed, the ECU for automatically controlling the engine is started.
When a control signal for engine restart is sent from 1
In step 208, the motor current gradual decrease coefficient λ (t) is set to 0.0, fmode is set to 3, and the process proceeds to step 209 described above. Here, fmode = 3 indicates a standby mode of the motor current gradually increasing process.

The determination as to whether or not the elapsed time Ts from the automatic stop of the engine in step 204 is longer than the standby time Tw1 corresponds to the determination means of the present invention for determining whether or not the predetermined time has elapsed.

In order to gradually decrease the motor current, a delay filter such as the following equation 2 can be used instead of using the motor current decrease coefficient λ (t) described in step 206. Here, a represents a filter constant,
It is a real value in the range of 0 <a <1.

[0060]

## EQU2 ## Imm (tn) = a.times.Imm (tn _-1 ) + (1
-A) × Im Next, the control algorithm of the motor current gradual increase process in step 115 will be described with reference to FIG.

First, in step 301, it is determined whether or not fmode is 3. If it is determined that fmode = 3, it is determined in subsequent step 302 whether or not the engine has been restarted. Here, confirming that the engine has been restarted means confirming that the engine speed has become higher than the speed of the starter and the engine has started to rotate by itself. Generally, when an engine start signal is sent to the starter and the engine speed exceeds a predetermined speed (cranking speed), it is determined that the engine has been restarted.

If the restart of the engine is confirmed, fmode is set to 4 in step 303. Here, fmode = 4 represents the execution mode of the motor current gradual increase process.

Then, in the subsequent step 304, when the motor current gradual increase processing is executed, the motor current gradual increase coefficient λ
The calculation of (t) is performed. This motor current gradual increase coefficient λ (t)
Can be obtained by storing as a positive monotone increasing function with respect to time t as shown in FIG. The motor current gradual increase coefficient λ (t) is adapted according to the driver's feeling.

In the following step 305, it is determined whether or not the motor current gradual increase coefficient λ is 1.0. When it is determined that the motor current gradual increase coefficient λ (t) is not 1.0,
In step 307, the final target motor current Imm is calculated based on the following equation 3, and the motor current gradual increase process ends.

[0065]

Imm = λ (t) × Im On the other hand, if it is determined in step 301 that fmode = 3, the process proceeds to step 304 described above.

If it is determined in step 302 that the restart of the engine is not to be confirmed, the process proceeds to step 307 in which the motor current gradually increasing coefficient λ (t) is set to 0.0 in step 308.

If it is determined in step 305 that the motor current gradual increase coefficient λ (t) is 1.0, fmode is set to 0.0, and the flow shifts to step 307 described above.

Incidentally, in order to gradually increase the motor current, instead of using the motor current gradual increase coefficient λ (t) described in step 304, a delay filter such as the following equation 4 can be used. Here, a represents a filter constant,
It is a real value in the range of 0 <a <1.

[0069]

## EQU4 ## Imm (tn) = a.times.Imm (tn _-1 ) + (1
-A) × Im As described above, according to the present embodiment, in the case of the automatic engine stop mode, the auxiliary steering force applied to the steering is gradually reduced by executing the motor current gradually decreasing process (step 114). The driver does not feel uncomfortable when the vehicle stops automatically. In the case of the engine restart mode, the motor current gradually increases (step 115).
Since the auxiliary steering force applied to the steering is gradually increased by executing the above, the driver does not feel uncomfortable when the engine is restarted.

Further, the motor current gradually decreasing process (step 11)
In 4), by providing the standby time Tw1, the motor current gradual decrease process is not performed immediately after the automatic engine stop, the auxiliary steering force is maintained, and the motor current gradual decrease process is performed after the predetermined standby time Tw1 has elapsed. Since it is performed, it can be made to match the feeling of the driving car.

Further, since the auxiliary steering force given to the steering is given by the driving force of the electric motor,
When suppressing a sudden change in the auxiliary steering force, for example, it is possible to easily set the control characteristics when decreasing or increasing the driving force.

Also, by making the standby time Tw1 variable, when the remaining amount of the battery is small or when the electric auxiliary machine is being driven, the motor current gradually decreasing process is immediately executed to automatically stop the engine. The time for maintaining the driving force of the electric motor at the time is shortened, so that electricity can be saved.

Although the present embodiment has been described with respect to executing both the motor current gradual decrease process (step 114) and the motor current gradual increase process (step 115),
The invention is not limited to this, and one of them may be executed.

[Second Embodiment] In the second embodiment,
As a power steering device, a hydraulic power steering device that adjusts an auxiliary steering force given to a steering by hydraulic pressure will be described.

First, an outline of a conventional hydraulic power steering device will be described with reference to FIGS. 10 (a) and 10 (b).

FIG. 10A is a diagram showing a state where there is no steering input and no auxiliary steering force is applied.
(B) is a diagram showing a state in which there is a steering input and an auxiliary steering force is applied.

As shown in FIG. 10 (a), the hydraulic power steering device includes a power steering pump (hereinafter, referred to as a PS pump) 8 for discharging a working oil that forms a working fluid for generating an auxiliary steering force. A return cylinder 11 that supplies hydraulic oil from the PS pump 8 and provides an auxiliary steering force to steering, and a state of the hydraulic oil supplied to the return cylinder 11 is determined by a spool valve according to a steering input. The control valve 15 is switched by displacing the control valve 10.

The valve housing 1 of the control valve 15
Reference numeral 4 denotes an inflow port P into which hydraulic oil discharged from the PS pump flows, supply ports C ₁ and C ₂ for supplying hydraulic oil to the return cylinder 11, and a drain for returning hydraulic oil to the oil tank 9. Ports T ₁ and T ₂ are formed.

The return cylinder 11 is provided with a rack bar 12 that is displaced in response to hydraulic oil supplied through the supply ports C ₁ and C ₂ of the control valve 15.

In the hydraulic power steering apparatus configured as described above, when there is no steering input and the spool valve 10 is in the neutral position, the hydraulic oil supplied from the PS pump 8 flows through the inflow port P. However, since the inflow port P and the drain ports T ₁ , T ₂ are in communication with each other, they return to the oil tank 9 through the drain ports T ₁ , T _2, and as a result, the rack bar of the return cylinder 11 No auxiliary steering force is applied to the wheel 12.

On the other hand, FIG. 10B shows a state in which the spool valve 10 of the control valve 15 is displaced by X by the steering input. The movement of the spool valve 10 causes the inflow port P and the drain port T to move. _{1, T 2} and communication with the supply port _{C 1} is cut off. For this reason,
Hydraulic oil supplied from the PS pump 8 A chamber by being filled in the A compartment of the backward cylinder 11 from the inlet port P through the supply port C ₂ becomes high. At this time, the movement of the spool valve 10, since the B chamber of backward cylinder 11 becomes drain port T ₁ and communicate with each other via the supply port C _1, operating oil supply port C ₁ of B _chamber, the drain port T By returning to the oil tank 9 through ₁ , the pressure in the chamber B becomes low. As a result, the room A becomes high pressure and the room B becomes low pressure, so that an auxiliary steering force is applied to the rack bar 12.

However, in such a hydraulic power steering system, when the engine is automatically stopped in a steering state, the PS pump 8 is stopped and the working oil filled in the return cylinder 11 is supplied to the PS through the inflow port P. Backflow to the pump 8 suddenly causes the auxiliary steering force to disappear, giving the driver an uncomfortable feeling. When the engine is automatically restarted in the steering state, the operation of the PS pump 8 causes the return cylinder 11 to restart.
There is a case where the hydraulic oil is suddenly filled into the vehicle and an auxiliary steering force is applied to give a driver an uncomfortable feeling.

Therefore, in the present embodiment, as shown in FIG. 11, a check valve 16 is provided between the control valve 15 and the PS pump 8 to prevent the backflow of hydraulic oil from the control valve 15 to the PS pump 8. I have.

Further, the check valve 16 and the control valve 1
5, an accumulator 17 for accumulating hydraulic oil discharged from the PS pump 8 is provided.

The check valve 16 and the accumulator 17 correspond to the auxiliary steering force adjusting means of the present invention.

By providing the check valve 16 in this manner, even when the PS pump 8 is stopped due to the automatic stop of the engine, the check valve 16 prevents the backflow of the hydraulic oil to the PS pump 8 and the auxiliary valve. It is possible to prevent the steering force from suddenly disappearing.

Thereafter, the working oil gradually flows to the drain ports T ₁ and T ₂ through the gap between the valve housing 14 and the spool valve 10, so that the auxiliary steering force can be gradually reduced.

Further, when the accumulator 7 is provided, when the engine is automatically restarted, the pressure at the time when the hydraulic oil suddenly flows out of the PS pump 8 is absorbed by the accumulator 17 so as to give a temporal change to the returning cylinder. By supplying the operating oil to the auxiliary steering force 11, the auxiliary steering force can be gradually increased.

As described above, according to the present embodiment, when the engine is automatically stopped, the check valve 16
By preventing the backflow to the S pump 8, it is possible to prevent the assist from suddenly disappearing, and the driver does not feel uncomfortable.

Further, the pressure at the time when the working fluid suddenly flows out of the PS pump 8 after the automatic restart of the engine is absorbed by the accumulator 17, and the pressure is changed over time to gradually increase the auxiliary steering force. And the driver does not feel uncomfortable.

As shown in FIG. 12, instead of attaching the check valve 16 and the accumulator 17, the PS pump 8
By installing a pressure regulating valve 19 (corresponding to an auxiliary steering force adjusting means of the present invention) between the control valve 15 and the control valve 15, the hydraulic oil is adjusted by adjusting the pressure regulating valve 19 when the engine is automatically stopped or restarted. You may make it decrease gradually and increase it.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a control system according to a first embodiment.

FIG. 2 is a flowchart illustrating a control algorithm of the electric power steering control device.

FIG. 3 is a diagram showing a map function for calculating a basic assist torque Ta in step 103 of FIG. 2;

4 is a return compensation torque Tr in step 106 of FIG.
FIG. 4 is a diagram showing a map function for calculating the following equation.

FIG. 5 is a diagram showing a map function for calculating a damper torque Td in step 107 of FIG. 2;

FIG. 6 is a flowchart showing a control algorithm of a motor current gradual decrease process.

FIG. 7 is a diagram showing a time function for calculating a motor current gradual decrease processing coefficient in step 206 of FIG. 6;

FIG. 8 is a flowchart illustrating a control algorithm of a motor current gradually increasing process.

FIG. 9 is a diagram showing a time function for calculating a motor current gradual increase processing coefficient in step 104 of FIG. 8;

FIG. 10 is an explanatory view showing the configuration and operation of a conventional hydraulic power steering apparatus, in which (a) is an explanatory view of a neutral state and (b) is an explanatory view of a steering state.

FIG. 11 is an explanatory diagram for explaining the configuration and operation of the second embodiment.

FIG. 12 is a configuration diagram showing another form of the second embodiment.

[Explanation of symbols]

 1 ECU for Automatic Engine Control 2 ECU for Electric Power Steering 5 Electric Motor 6 Power Steering Gear 7 Torque Sensor 8 Power Steering (PS) Pump 10 Spool Valve 11 Return Cylinder 15 Accumulator 16 Check Valve 19 Pressure Regulator

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // B62D 101: 00 B62D 101: 00 119: 00 119: 00 127: 00 127: 00 F term (reference) 3D032 CC08 CC46 CC49 DA15 DA23 DA47 DA63 DA67 DB02 DB03 DC03 DC08 DC09 DC11 DC21 DC33 DC40 DD02 DD17 DE02 DE11 EC04 EC08 EC23 FF07 GG01 3D033 CA11 CA13 CA16 CA20 CA21 CA24 EB02 EB05 3D041 AA21 AA40 AA66 AB01 AC01 BA03 A01 BA01 BA09 AE00 BA22 CA02 CB05 CB09 DA01 DA12 DB05 DB20 EA05 EB00 EB09 EC01 FB01 FB02 FB03

Claims (10)

[Claims] 1. A power steering mounted on a vehicle provided with an automatic engine control device for automatically stopping or restarting an engine of the vehicle when a predetermined condition is satisfied, and for adjusting an auxiliary steering force applied to the steering of the vehicle. A control device, wherein when the engine of the vehicle is automatically stopped or started,
A power steering control device, comprising: an auxiliary steering force adjusting unit that suppresses a sudden change in the auxiliary steering force applied to the steering. 2. A power steering control device which receives a control signal relating to automatic stop or restart of an engine, and adjusts an auxiliary steering force applied to a steering of the vehicle based on the control signal. A power steering control device comprising auxiliary steering force adjusting means for suppressing a sudden change in the auxiliary steering force applied to the steering in response to a control signal. 3. The power steering control device according to claim 1, wherein the auxiliary steering force applied to the steering is provided by a driving force of an electric motor. A power steering control device, wherein a sudden change in the auxiliary steering force is suppressed by controlling a driving force. 4. The power steering control device according to claim 3, wherein the driving force of the electric motor is gradually reduced when an engine of the vehicle stops automatically. 5. The power steering control device according to claim 3, wherein the driving force of the electric motor is gradually increased when the engine of the vehicle is automatically restarted. 6. The power steering control device according to claim 1, wherein the auxiliary steering force applied to the steering is provided by a pressure of a working fluid supplied from a hydraulic pump, and the auxiliary steering force is provided. The power steering control device according to claim 1, wherein the adjusting means comprises a check valve for preventing the working fluid from flowing back to the hydraulic motor. 7. The power steering control device according to claim 1, wherein the auxiliary steering force applied to the steering is provided by a pressure of a working fluid supplied from a hydraulic pump, and the auxiliary steering force is provided. The power steering control device according to claim 1, wherein the adjusting means comprises pressure accumulating means for accumulating the working fluid supplied from the hydraulic pump. 8. The power steering control device according to claim 1, wherein the auxiliary steering force applied to the steering is provided by a pressure of a working fluid supplied from a hydraulic motor, and the auxiliary steering force adjustment is performed. The power steering control device is characterized in that the means comprises a pressure regulating valve for adjusting the pressure of the working fluid. 9. The power steering control device according to claim 1, further comprising: a determination unit configured to determine whether a predetermined time has elapsed since the engine was automatically stopped. The auxiliary steering force when the engine is automatically stopped is maintained until it is determined that the predetermined time has elapsed, and when it is determined that the predetermined time has elapsed, a sudden change in the auxiliary steering force is suppressed. A power steering control device for performing a process. 10. The power steering control device according to claim 9, wherein the predetermined time is based on at least one of a remaining amount of a battery of the vehicle and a driving state of an auxiliary device arranged in the vehicle. A power steering control device characterized by being variable.