JPH06344937A - Motor-driven type power steering device - Google Patents

Abstract

PURPOSE:To enable a driver to take a proper countermeasure in response to the generation of anomaly, by surely information the driver of the anomaly in the traveling of a vehicle. CONSTITUTION:A motor-driven type power steering device is equipped with a motor M1 for generating the steering assisting force, steering state detecting device M2, and a controller M3 for controlling the steering assisting force by controlling the motor by the control quantity corresponding to the steering state. The anomaly in the traveling of a vehicle is detected by an anomaly detector M4, and an alarm generating device M5 is operated by an alarm output device M6 on the basis of the detection of anomaly, and a visual alarm or audio alarm is generated, and a steering wheel is finely vibrated by adding the fine vibration component to the control quantity for the motor, and also the alarm as the fine vibration variation of the steering torque is transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering device for vehicles such as automobiles, and more particularly to an electric power steering device.

[0002]

2. Description of the Related Art In a vehicle such as an automobile, an abnormality detection device generally detects an abnormality in the running of the vehicle, and when an abnormality is detected, an alarm generator is activated to cause an abnormality to the driver of the vehicle. Is being notified of the occurrence of. For example, Japanese Utility Model Publication No. 40-16188 discloses an alarm device which detects a cooling water temperature of an engine by a cooling water temperature sensor and activates an alarm generating device such as an alarm lamp or a buzzer when the cooling water temperature reaches a predetermined temperature. Have been described.

According to the alarm device as described above, when an abnormality occurs in the running of the vehicle and the abnormality is detected by the abnormality detecting device, the alarm device is activated to indicate that the abnormality has occurred to the driver of the vehicle. Since the alarm is issued, the driver can take appropriate measures against an abnormal occurrence such as a stop of the vehicle.

[0004]

However, in the conventional alarm device as described above, since the alarm is issued as a visual alarm or an audible alarm, the driver of the vehicle immediately recognizes the alarm depending on the situation. You may not be able to
Therefore, the driver may not be able to take appropriate measures against the occurrence of an abnormality immediately in response to the occurrence of the abnormality.

In view of the above-mentioned problems in the conventional alarm device for notifying the driver of a vehicle running abnormality, the present invention can surely notify the driver of a vehicle running abnormality. An object of the present invention is to provide an improved electric power steering device.

[0006]

According to the present invention, as described above, the above object is to provide a motor M1 for generating a steering assist force and a steering state detection for detecting a steering state of a vehicle, as shown in FIG. An electric power steering apparatus having means M2 and control means M3 for controlling the steering assist force by controlling the motor with a control amount according to the detected steering state is used to detect an abnormality in vehicle running. Then, the abnormality detecting means M4 for outputting the abnormality detecting signal and the alarm generating means M5 for issuing a visual alarm or an audible alarm based on the abnormality detecting signal are operated, and a minute vibration component is added to the control amount to the motor. And an alarm output means M6.

[0007]

According to the above-mentioned structure, when an abnormality occurs in the running of the vehicle and the abnormality is detected by the abnormality detecting means M4, the abnormality detecting signal is output by the abnormality detecting means, and an alarm is output based on the abnormality detecting signal. Alarm generator M by means M6
5 is activated and a visual alarm or an audible alarm is issued, and a minute vibration component is added to the control amount to the motor. Therefore, in addition to the visual alarm or the audible alarm by the alarm generator M5, As a result, an alarm is given by a minute vibration of the steering wheel, which enables the driver to more surely recognize the occurrence of the abnormality as compared with the conventional alarm device.

[0008]

[Supplementary Explanation of Means for Solving the Problem] Abnormalities in vehicle running include abnormalities in the vehicle itself, such as a failure of the power steering device, abnormalities in the driver itself, such as the driver's dozing of the vehicle, and road surface abnormalities. There is an abnormality in the traveling environment of the vehicle such as a reduction in the friction coefficient due to freezing, and the abnormality of the vehicle itself is detected by the steering state detection means such as the disconnection or short circuit of the torque sensor of the electric power steering device. There are serious anomalies that cannot be detected and minor anomalies that the steering state detection means cannot accurately detect the steering state of the vehicle, such as the offset of the torque sensor.

According to one embodiment of the present invention, the alarm output means M6 determines whether the abnormality detected by the abnormality detecting means M4 is a serious abnormality or a minor abnormality, and the detected abnormality is detected. In the case of a slight abnormality, an alarm generating means M5
And a minute vibration component is added to the control amount to the motor, and when the detected abnormality is a serious abnormality, the alarm generation means M5 is activated and the control amount to the motor is set to 0 to perform power assist. Configured to stop.

According to another embodiment of the present invention,
The electric power steering device has means for determining whether or not the driver of the vehicle has recognized any of the alarms by estimating,
When it is determined that the driver has recognized the alarm, the alarm generation means M5 is stopped and the alarm output stopping means for stopping addition of the minute vibration component to the control amount to the motor is provided. Even after the driver of the vehicle recognizes the occurrence of an abnormality or an alarm indicating the abnormality, it is avoided that the alarm generation means continuously gives a visual or audible alarm or continuously gives a small vibration to the steering wheel. To be done.

In the electric power steering apparatus of the present invention, the minute vibration component added to the control amount to the motor is
The driver of the vehicle can surely recognize the alarm given as a minute vibration of the steering wheel, and is set to a minute vibration of a frequency and an amplitude that does not hinder normal power assist. Further, the minute vibration component does not necessarily have to have a sinusoidal shape, and may have a sinusoidal waveform, a trapezoidal waveform, or the like in which a portion having an amplitude of a predetermined value or more is cut.

[0012]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 2 is a schematic configuration diagram showing one embodiment of the electric power steering apparatus according to the present invention, and FIG. 3 is FIG.
3 is a block diagram showing an electronic control device shown in FIG.

In FIG. 2, reference numeral 10 denotes a steering wheel. The steering wheel 10 is a rack bar 1 as a steering linkage member via a steering shaft 12 and a steering gear box 14.
6 is driven. A power unit 20 is drivingly connected to the steering shaft 12 by a gear reduction mechanism 18. The power unit 20 is a motor 22
And an electromagnetic clutch 24 for selectively drivingly connecting the gear reduction mechanism 18 and the motor 22.

In the illustrated embodiment, the steering shaft 12 is provided with a steering angle sensor 26 for detecting the steering angle θ and a torque sensor 28 for detecting the steering torque T, and the outputs of these sensors are electronic. It is supplied to the control device 32. Further, the electronic control unit 32 has a signal indicating the vehicle speed V detected by the vehicle speed sensor 34, a signal indicating the rotation angle φ of the motor 22 detected by the rotation angle sensor 36, and left and right detected by the wheel speed sensors 38R and 38L, respectively. A signal indicating the wheel speeds VL and VR of the front wheels,
Alarm stop switch (S
W) A signal indicating whether or not 40 has been operated, a brake switch 4 that is turned on when the vehicle driver brakes
2, a signal indicating whether or not the vehicle is braked, the depression amount sensor 4
A signal indicating the amount of depression of the accelerator pedal, which is not shown in the figure, detected by 4 is input.

As shown in detail in FIG. 3, electronic controller 32 includes a microcomputer 48, which is a central processing unit (CPU) 50.
, Read only memory (ROM) 52, random access memory (RAM) 54, and input port device 56
And an output port device 58, which are connected to each other by a bidirectional common bus 60.

The input port device 56 appropriately processes the signal input thereto, and in accordance with the instruction of the CPU 50 based on the control program stored in the ROM 52, the CPU and R
The processed signal is output to the AM 54. ROM 52 is a control program shown in FIGS. 4 and 7, maps corresponding to the graphs shown in FIGS. 5 and 6,
Also, the waveform of the minute vibration component Tm described later is stored. C
The PU 50 is adapted to perform various calculations and signal processing based on the control program shown in FIG. 4, as will be described later.

As will be described later, the electronic control unit 32 outputs a control signal to the electromagnetic clutch 24 via the drive circuit 64 at the start of the operation to drive and connect the gear reduction mechanism 18 and the motor 22 and is detected by each sensor. The steering assist amount is calculated based on the steering torque T and the like, and a voltage signal corresponding to the assist amount is output to the motor 22 via the drive circuit 62. Further, as will be described in detail later, when an abnormality such as an abnormality in each sensor or a decrease in the friction coefficient of the road surface occurs, the electronic control unit 32 determines whether the abnormality is serious, and if the abnormality is significant. The control signal is output to the alarm lamp 66 to blink the alarm lamp, the electromagnetic clutch 24 is released, the steering assist amount is set to 0, and the power assist is stopped. If the abnormality is slight, the alarm lamp is turned on. At the same time, a minute vibration component is added to the steering assist amount, so that the steering wheel is slightly vibrated.

The operation of the illustrated embodiment will now be described with reference to the flow charts shown in FIGS. The control according to these flowcharts is started by closing an ignition switch (not shown), and the control according to the flowchart shown in FIG. 7 is executed by interruption every predetermined time. Further, in the flow charts shown in FIGS. 4 and 7, the flag F relates to whether or not there is an abnormality in running the vehicle,
1 indicates that a slight abnormality has occurred, and 2 indicates that a serious abnormality has occurred. Further, the flag Fa relates to whether or not the minute vibration component is given to the drive current for the motor 22, and 1 indicates that the minute vibration component is given to the drive current.

First, in step 10, the control signal is output to the electromagnetic clutch 24 via the drive circuit 64 to connect the clutch, and in step 20, the steering angle θ detected by the steering angle sensor 26 is set. A signal indicating the steering torque T detected by the torque sensor 28,
A signal indicating the vehicle speed V detected by the vehicle speed sensor 34 is read.

At step 30, the basic assist amount Tab is calculated from the map corresponding to the graph shown in FIG. 5 based on the steering torque T read at step 20.
In step 40, the vehicle speed coefficient Kv is calculated from the map corresponding to the graph shown in FIG. 6 based on the vehicle speed V read in step 20. In step 50, the assist amount Ta is calculated as the product of the basic assist amount Tab calculated in step 30 and the vehicle speed coefficient Kv calculated in step 40.

At step 60, it is judged if the flag F is 2, and if it is judged that F = 2, then at step 70 the control signal to the electromagnetic clutch 24 is sent. After the output is stopped and the clutch is released, the power assist control according to the flowchart shown in FIG. 4 is ended, and when it is determined that F = 2 is not satisfied, the routine proceeds to step 80.

In step 80, it is judged whether or not the flag Fa is 1, and when it is judged that Fa = 1 is not satisfied, the routine proceeds to step 100 and Fa
When it is determined that = 1, the assist amount Ta is set to the sum of Ta and the minute vibration input value Tm in step 90, and then the process proceeds to step 100. Step 100
Is calculated in step 50 or step 90
The control signal corresponding to the assist amount Ta set at is output to the motor 22 via the drive circuit 62 so that the assist steering force is controlled to a value corresponding to the assist amount Ta, and then the process returns to step 20.

In step 200 of the flow chart shown in FIG. 7, a signal indicating the steering angle θ detected by the steering angle sensor 26, a signal indicating the steering torque T detected by the torque sensor 28, and a vehicle speed sensor 34. The signal indicating the vehicle speed V detected by the rotation angle sensor 36 and the signal indicating the rotation angle φ of the motor 22 detected by the rotation angle sensor 36 are read, and whether or not an abnormality in vehicle traveling has occurred based on these signals. When it is determined that the abnormality has not occurred, the flag F is set to 0 in step 210.
After being reset to step 200, the process returns to step 200, and when it is determined that an abnormality has occurred, the process proceeds to step 220.

It should be noted that the determination as to whether or not an abnormality in vehicle traveling has occurred may be performed in any manner. For example, the abnormality detection of the torque sensor 28 of the power steering device may be made by the same applicant as the applicant of the present application. Japanese Patent Application No. 4-2766
16 may be performed by the method described in the specification and drawings, and the abnormality detection of the motor 22 or the rotation angle sensor 36 may be performed by the correspondence between the control signal for the motor and the output of the rotation angle sensor. Further, the determination as to whether or not the driver of the vehicle is dozing may be performed by the method described in Japanese Patent Application Laid-Open No. 3-96439 of the same applicant as the present applicant, and the friction coefficient of the road surface is low. Whether or not the vehicle speed V detected by the vehicle speed sensor 34 and the vehicle speed Va estimated from the average value of the wheel speeds VL and VR of the left and right front wheels detected by the wheel speed sensors 38R and 38L is determined as a reference value. It may be performed by determining whether or not the value exceeds.

In step 220, it is determined whether or not the abnormality that has occurred is serious, and when it is determined that the abnormality is minor, the flag F is set to 1 in step 230. When the alarm lamp 66 is set and the alarm lamp 66 is turned on, and it is determined that the abnormality is serious, the flag F is set to 2 and the alarm lamp 66 is blinked in step 240.

In step 250, the count value N of the counter is set to No (a positive integer), and step 26
At 0, the flag Fa is set to 1 and step 27
At 0, waiting for a predetermined time is performed, and at step 280, the flag Fa is reset to 0.

In step 290, the signal from the alarm stop switch 40 is read, and based on the signal, it is judged whether or not the driver of the vehicle has operated the alarm stop switch. When it is determined that the alarm has been operated, the flag F is reset to 0 and the alarm lamp 66 is turned off in step 300, and when it is determined that the alarm stop switch has not been operated, step 310 is performed. Go to.

In step 310, a signal is read from the brake switch 42, and based on the signal, it is determined whether or not the driver of the vehicle has performed a braking operation, and the braking operation is performed. When it is determined that the braking operation is not performed, the process proceeds to step 300. When it is determined that the braking operation is not performed, the process proceeds to step 320.

In step 320, the depression amount sensor 4
A signal indicating the depression amount of the accelerator pedal is read from 4, and it is determined whether or not the deceleration operation is performed by the driver of the vehicle based on the signal, and it is determined that the deceleration operation is performed. When it is performed, the process proceeds to step 300, and when it is determined that the deceleration operation is not performed, the count value N of the counter is decremented by 1 in step 330.

At step 340, the count value N is 0.
If it is determined that N = 0 is not satisfied, the process returns to step 260 after waiting for a predetermined time in step 350, and N = 0. If it is determined that the alarm stop switch 40 is reset in step 360, then step 20
Return to 0.

Thus, according to the embodiment shown in the figure, if no abnormality is occurring in the running of the vehicle, a negative determination is made in step 200 and the flag F is determined in step 210.
Is reset to 0, steps 20 to 80 and step 100 are repeatedly executed, whereby a required steering assist torque is applied from the power unit 20 to the steering shaft 12 to perform power assist.

Further, if a serious abnormality occurs in the running of the vehicle, a yes determination is made in steps 200 and 220, and the alarm lamp 66 blinks in step 240 to indicate that a serious abnormality has occurred. Is issued, the flag F is set to 2, and the determination in step 60 is YES, the clutch 24 is released in step 70 and the assist amount Ta is set to 0. Thus, the power assist is stopped and the power steering device is switched to the manual steering device.

When a slight abnormality in the running of the vehicle occurs, a yes / no determination is made in steps 200 and 220, respectively, and the alarm lamp 66 is turned on in step 230, whereby the driver of the vehicle operates. A visual alarm is issued to. In step 260, the flag Fa
Is set to 1 and YES is determined in step 80, so that the assist amount Ta is determined in step 90.
Is set to the sum of Ta and the minute vibration component Tm, and the control signal corresponding to the assist amount is output to the motor 22 in step 100 to give the minute vibration component to the rotation of the motor, whereby the steering is performed. Wheel 1
When the minute vibration is applied to 0, the driver of the vehicle is alerted by the minute vibration change of the steering torque.

Also in this case, steps 290, 310, 3
Unless YES is determined in any one of steps 20, steps 260 to 280 are repeatedly executed No times until YES is determined in step 340, thereby causing an alarm by slightly vibrating the steering wheel. Since it is performed No times intermittently, it is possible to surely inform the driver of the vehicle that a slight abnormality has occurred in the running of the vehicle.

Also according to the illustrated embodiment, step 29
At 0, it is determined whether the alarm stop switch has been operated, at step 310 it is determined whether a braking operation has been performed, and at step 320 whether a deceleration operation has been performed. By determining whether or not the driver of the vehicle has recognized a minor abnormality occurrence or an alarm indicating that, a driver has recognized a minor abnormality occurrence or an alarm. When the determination is made, the flag F is reset to 0 and the alarm lamp is turned off in step 300, and the alarm is released by this, so that the driver of the vehicle has generated a slight abnormality or the alarm thereof. It is possible to surely prevent the alarm from being continuously output despite the fact that the above is recognized.

Although the present invention has been described in detail above with reference to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art that it is possible.

For example, in the above-described embodiment, the driver of the vehicle determines whether or not the driver of the vehicle has recognized a slight abnormality in the running of the vehicle or an alarm indicating the abnormality. It is designed to be performed depending on whether or not the stop switch has been operated and whether or not the braking operation or the deceleration operation has been performed.However, it is not possible to determine whether or not the driver has recognized a minor abnormality or its alarm. It may be performed by other means.

Further, in the above-described embodiment, when an abnormality occurs in the running of the vehicle, the warning lamp 66 is turned on or blinked so that only a visual warning is generated. In addition to activating an alarm lamp, an audible alarm generator, such as a buzzer, may be activated.

Further, in the above embodiment, the basic assist amount Tab is calculated based on the steering torque T, and the assist amount Ta is calculated as the product of the basic assist amount Tab and the vehicle speed coefficient Kv which is increased or decreased according to the vehicle speed V. However, the assist amount may be calculated in any manner as long as it is calculated in accordance with at least the steering torque.

[0041]

As is apparent from the above description, according to the present invention, when an abnormality occurs in the running of the vehicle and the abnormality is detected by the abnormality detecting means M4, the abnormality detecting signal is output by the abnormality detecting means. Based on the abnormality detection signal, the alarm output device M6 activates the alarm generator M5 to generate a visual alarm or an audible alarm, and a minute vibration component is added to the control amount to the motor. In addition to a visual alarm or an audible alarm from the alarm generator M5, an alarm due to a minute vibration of the steering wheel is given, so that the driver can be more sure to recognize the occurrence of the abnormality as compared with the conventional alarm device. You can

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an electric power steering device according to the present invention in correspondence with the description of the claims.

FIG. 2 is a schematic configuration diagram showing one embodiment of an electric power steering device according to the present invention.

FIG. 3 is a block diagram showing the electronic control device shown in FIG. 2.

4 is a flowchart showing a routine of power assist control achieved by the electronic control device shown in FIGS. 2 and 3. FIG.

FIG. 5 is a graph showing a relationship between a steering torque T detected by a torque sensor and a basic assist amount Tab.

FIG. 6 is a graph showing a relationship between a vehicle speed V detected by a vehicle speed sensor and a vehicle speed coefficient Kv.

FIG. 7 is a flow chart showing a routine for abnormality determination achieved by the electronic control device shown in FIGS. 2 and 3.

[Explanation of symbols]

 10 ... Steering wheel 12 ... Steering shaft 14 ... Steering gear box 16 ... Rack bar 22 ... Motor 24 ... Electromagnetic clutch 26 ... Steering angle sensor 28 ... Torque sensor 32 ... Electronic control unit 34 ... Vehicle speed sensor 40 ... Warning stop switch 66 ... Warning lamp

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B62D 113: 00 119: 00

Claims (1)

[Claims] 1. A steering assist force is generated by controlling a motor for generating a steering assist force, a steering state detecting means for detecting a steering state of a vehicle, and a control amount according to the detected steering state. An electric power steering apparatus having control means for controlling, an abnormality detecting means for detecting an abnormality in vehicle running and outputting an abnormality detection signal, and an alarm for issuing a visual alarm or an audible alarm based on the abnormality detection signal. An electric power steering apparatus comprising: an alarm output unit that operates a generator and adds a minute vibration component to the control amount to the motor.