JPH0577750A - Electric power steering device - Google Patents

Abstract

PURPOSE:To obtain a steering feeling according to a driver's preference by judging the characteristic of a driver by means of an average vehicle speed and an average steering angle speed and controlling an electric motor for steering according to the judged characteristics of the driver. CONSTITUTION:An electric motor 12 is connected to an assist pinion 10 engaged with a rack 7 through a speed reducer 11, and the electric motor 12 is controlled by a controller C into which outputs from a vehicle speed sensor 14, a torque sensor 6, and a steering angle sensor 15 are input. In this control, an average of vehicle speed information and steering angle speed information stored multiple times repeatedly within a specified time is calculated. Next, the average value is applied to a specified pattern to determine to which group among sporty, standard, and mild groups the characteristic of a driver belongs. If it belongs to the sporty group, the output of the electric motor 12 will be reduced to reduce a power assist force and, if belongs to the others, it will be increased to increase the power assist force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric power steering device for a vehicle for power-assisting a steering force to reduce the steering force of a driver.

[0002]

2. Description of the Related Art In the conventional electric power steering apparatus shown in FIG. 8, a shaft 2 of a steering wheel 1 and a shaft 4 provided with a pinion 3 are linked via a column shaft 5, and a torque sensor is attached to the shaft 4. 6 is provided. Also, although the pinion 3 is engaged with the rack 7,
Both ends of the rack 7 are linked to the tire 9 via links 8. An assist pinion 10 is provided on the rack 7.
The assist pinion 10 is linked to the electric motor 12 via the speed reducer 11. The electric motor 12 is controlled by a controller 13, which includes a vehicle speed sensor 14
And the torque sensor 6 are connected.

Now, when the handle 1 is turned, its output is transmitted to the pinion 3, but at this time, the rack 7 does not move due to frictional resistance of the tire 9 or the like. However, the steering torque at that time is detected by the torque sensor 6 and input to the controller 13. Although the vehicle speed signal from the vehicle speed sensor 14 is also input to the controller 13, the output of the electric motor 12 is controlled according to the torque signal and the vehicle speed signal. When the electric motor 12 is driven in this way, the assist pinion 10 rotates to move the rack 7 and steer the tire 9.

[0004]

The power assisting force of the conventional device as described above is only fixedly determined according to the steering torque, and the structure for changing the assisting force according to the characteristics of the driver is required. It wasn't. Therefore, this conventional device has a problem that it is not possible to realize a steering feeling according to the taste of each driver. An object of the present invention is to provide a device that realizes a steering feeling according to the characteristics of each driver.

[0005]

According to the present invention, there is provided an electric motor equipped with a steering angle sensor for detecting a steering angle of a steering wheel, a vehicle speed sensor for detecting a vehicle speed, and a controller for controlling an electric motor according to both signals. It is based on the power steering device. While assuming the above device,
The controller of the present invention stores the vehicle speed and the steering angular speed, the step of reading the output signal from the steering angle sensor, the step of reading the signal from the vehicle speed sensor, the step of calculating the steering angular speed according to the steering angle. Steps, a timer processing step for repeating each of these steps a predetermined number of times, a step of deleting the upper and lower limit ranges of the data repeated a predetermined number of times, an average speed and an average steering from the remaining data. It is characterized in that it has a step of calculating an angular velocity and a step of judging a driver characteristic from an average speed and an average steering angular velocity, and that a steering feeling according to the driver characteristic is realized.

[0006]

Since the present invention is configured as described above, the controller determines the driver's characteristic based on the average vehicle speed and the average steering angular velocity, and controls the electric motor according to the characteristic.

[0007]

According to the power steering apparatus of the present invention, the characteristics of each driver can be automatically judged and the control can be performed according to the individuality of the driver. Therefore, the steering feeling according to the taste of each driver can be obtained. realizable.

[0008]

1 to 4, a shaft 2 of a handle 1 and a shaft 4 provided with a pinion 3 are linked via a column shaft 5 and a steering angle sensor 1 is attached to the shaft 2.
5 is provided, and the shaft 4 is provided with a torque sensor 6. Further, the pinion 3 is engaged with the rack 7, and both ends of the rack 7 are linked to the tire 9 via links 8. An assist pinion 10 is engaged with the rack 7, and the assist pinion 10 is linked to an electric motor 12 via a speed reducer 11. The electric motor 12 is controlled by a controller C, which includes a vehicle speed sensor 14, a torque sensor 6, and a steering angle sensor 15.
And are connected.

In this state, when the handle 1 is turned, its output is transmitted to the pinion 3. At this time, the tire 9
The rack 7 does not move due to the frictional resistance. However, the steering torque at that time is detected by the torque sensor 6 and input to the controller C. The controller C has
Although vehicle speed signals from the vehicle speed sensor 14 and the steering angle sensor 15 are also input, the output of the electric motor 12 is controlled according to these signals. When the electric motor 12 is driven in this way, the assist pinion 10 rotates to move the rack 7 and steer the tire 9.

Then, the controller C described above operates as shown in FIG. 2 in a predetermined one minute. First, when the operation of the control system is started, it is determined in step I whether the steering angle sensor 15 is operating. If the steering angle sensor 15 is not operating, it is determined that the steering wheel 1 is not turned and the process returns to the original state. If the steering angle sensor 15 is operating, it is determined that the steering wheel 1 is turned off, and the process proceeds to step II.

In the step II, the signal from the vehicle speed sensor 14 is read and stored, and the process proceeds to the step III. Furthermore, the steering angle is read in the third step, and the steering angular velocity is calculated from the steering angle in the fourth step. Then, the vehicle speed and the steering angular speed are stored in the V-th step. Furthermore, in the VI step,
The timer process that repeats the operation of steps I to V 20 times every 0.05 seconds is repeated, and if it is repeated 20 times, the VI
Move to step I. In the VIIth step, the maximum 5 sets and the minimum 5 sets of the vehicle speed information and the steering angular velocity information, which are repeatedly stored 20 times as described above, are deleted, and the intermediate 10 data are left.

In step VIII, the average value of each of the remaining 10 sets of vehicle speed and steering angular velocity is calculated, and the calculated average value is written in step IX. Then, in the Xth step, it is determined whether or not there are 5 sets of data written in the IXth step. If the number of sets is less than 5, the process returns to the Ith step again to make average data. Then, when the average data reaches 5 sets, the process moves to the XIth step to read the 5 sets of data,
Go to the XII step and calculate the average value of these 5 sets of data.

Further, in step XIII, the averaged value is applied to a predetermined pattern to determine whether the driver characteristic is sporty, standard or mild. If the result of the determination is that it is sporty, the process proceeds to the XIV step, in which the output of the electric motor 12 is reduced and the power assist force is reduced. On the contrary, if it is not sporty, move to the XV step,
The output of the electric motor 12 is increased to increase the power assist force.

Then, the pattern for judging the characteristics of the driver is determined on the assumption of the left and right composite corners having the same radius of curvature as shown in FIG. For example, when a mild driver drives, the steering angular velocity is low at low speed. On the other hand, sporty people drive at high speed and have high steering angular speed. The characteristics of the driver are determined according to such a general situation. Note that FIG. 4 shows differences in steering angle of the steering wheel due to individual differences, and A, B, and C in the figure correspond to points A, B, and C of cornering in FIG. 3, respectively. Further, FIG. 5 shows a comparison of the sporty steering angular velocities with respect to the standard steering, and FIG. 6 shows a mild steering angular velocity with respect to the standard steering. Then, as is clear from FIGS. 4 to 6, when comparing standard steering, sporty, and mild at the same corner, the sporty has a relatively high vehicle speed at point A, so the steering wheel steering time is standard. It is shorter than the steering. Therefore, as shown in FIG. 5, the steering angular velocity becomes faster than the standard steering. In addition, since the mild type has a relatively low vehicle speed, the steering time for steering wheel becomes longer than that for standard steering. Therefore, as shown in FIG. 6, the steering angular velocity also becomes slow.

The assist force pattern is changed based on the above-mentioned criteria. An example of the change pattern is shown in FIG. In FIG. 6, it is determined from the steering angular velocity and the vehicle speed whether the steering pattern of the driver is a sporty group or a mild group by comparing with the standard steering pattern. For the sporty group, the assist force is smaller than that of the standard assist pattern. is doing. In addition, the assist power for the mild group is larger than the standard assist pattern. The vehicle speed in FIG. 6 is set to 40 km.

When the adjustment of the assisting force is completed as described above, the process shifts to the XVI step to erase only one set of the oldest stored data in the past, and the data is moved down in the XVII step. Then, the process moves to the I step again, and the new data is stored, and at the X step, it is judged whether or not there are 5 sets of data including the new data. Transition. In this way, while memorizing the latest data of the driver and erasing the past data, the data is updated so that the control based on the latest data can always be performed.

According to the power steering device described above, the assist force can be made larger than that of the standard pattern for a mild driver whose vehicle speed is relatively low during cornering and whose steering angular velocity is low. In addition, for a sporty driver whose vehicle speed is relatively high during cornering and whose steering angular speed is high, the assist force can be made smaller than that of the standard pattern. In addition, both vehicle speed and steering angular velocity are set to a standard pattern of assist force for a standard driver.
Therefore, it is possible to realize the steering feeling according to the characteristics of the driver.

[Brief description of drawings]

FIG. 1 is a structural diagram.

FIG. 2 is a flow chart diagram.

FIG. 3 is an explanatory diagram showing a situation of cornering.

FIG. 4 is a graph showing driver characteristics as a function of steering angle and time.

FIG. 5 is a graph showing a sporty characteristic as a relationship between steering angular velocity and time.

FIG. 6 is a graph showing the characteristics of the mild group in terms of the relationship between steering angular velocity and time.

FIG. 7 is a graph showing a relationship between an assist force of an electric motor and a torque voltage according to a driver characteristic.

FIG. 8 is a structural diagram showing a conventional device.

[Code]

 1 Handle C controller 14 Vehicle speed sensor 15 Steering angle sensor

Claims (1)

[Claims] 1. An electric power steering apparatus comprising: a steering angle sensor for detecting a steering angle of a steering wheel; a vehicle speed sensor for detecting a vehicle speed; and a controller for controlling an electric motor in accordance with these signals.
A step of reading an output signal from the steering angle sensor, a step of reading a signal from the vehicle speed sensor, a step of calculating a steering angular velocity according to the steering angle, a step of storing these vehicle speed and steering angular velocity, and each of these steps A timer processing step for repeating a predetermined number of times a predetermined number of times, a step of deleting the upper and lower limits of the data repeated the predetermined number of times, and a step of calculating an average speed and an average steering angular speed from the remaining data. And an electric power steering apparatus that realizes a steering feeling according to the characteristics of the driver, including the step of determining the characteristics of the driver from the average speed and the average steering angular speed.