JPS61220971A - Driving state judging device for automobile - Google Patents

Abstract

PURPOSE:To make an accurate judgment performable, by storing steering angle signals as a lot of numerical values corresponding to a steering angle and renewing them each, while judging a driving state from an index showing the driving state to be operated from frequency to be found out of lots of numerical values and the total number of a lot of these numerical values. CONSTITUTION:A frequency distribution state in a steering angle differs between the case of driving at a mountain path where right-angled meanders are less despite many curves and the case of driving at an urban district where right-angled meanders are much despite few curves. Accordingly, the steering angle of a steering wheel 20 is detected by a steering angle detecting device 1, and numerical values commensurate to the steering angle are stored in a memory device 2, while the memory contents are renewed. Then, frequency excluding numerical values in and around a mean value and numerical values beyond a relatively extensive range centering on the vicinity of the mean value from a number of these stored numerical values is counted by a counting device 3 and, after an index showing a driving state is operated by an operational device 4 by subtraction between the frequency and the total number of a number of these numerical values, a judgment of the driving state is performed by a judging device 5 with the index.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a driving state determination device used when controlling steering force and vehicle height according to the driving state of an automobile.

[Prior art]

Conventionally, the driving state of a car has usually been judged based on the vehicle speed, and based on this judgment result, the assist force of the power steering system is adjusted so that, for example, the steering force is light in low speed ranges and heavy in high speed ranges. There is something that controls it.

[Problem that the invention seeks to solve]

In the conventional technology that determines the driving state based on the vehicle speed, for example, in the case of the above-mentioned assist force control, the control pattern of the assist force with respect to the vehicle speed, steering angle, etc. is constant, whether driving on a mountain road or in the city. There was a problem in that the control pattern of the assist force did not change, and the steering force for each driving state could not be obtained. Similar problems exist in vehicle height control and suspension stiffness control of automobiles.

In order to solve this problem, a system has been developed in which a plurality of control patterns for assist force are provided in steering force control, and the control pattern is manually selected as appropriate depending on the driver's preference or driving conditions.

In order to eliminate the trouble of manual selection, it is conceivable to automatically determine the driving state and select a control pattern. For this purpose, the applicant had previously filed a patent application filed in 1983.
No. 112303 was filed, and a proposal was made to determine the driving state of an automobile based on the distributed state of steering angle signals. However, as stated in the same application, although it is possible to distinguish between high-speed driving and mountain road driving based on the dispersion state of the steering angle signal, the dispersion state is different between city driving and mountain road driving. Therefore, it has been difficult to reliably distinguish between the two. The present invention utilizes the fact that the frequency distribution of steering angles is different between mountain road driving and city driving to reliably distinguish and judge these driving conditions.

[Means for solving problems]

For this purpose, as shown in FIG. 1, the vehicle running state determining device according to the present invention includes a steering wheel 20 that detects a steering angle and generates a steering angle signal. a detection means 1; a storage means 2 for simultaneously storing a large number of numerical values corresponding to the steering angle by sequentially inputting the steering angle signal at predetermined intervals and updating the stored contents; Counting means for counting the remaining frequency counts after excluding, from the large number of numerical values, numerical values within a relatively narrow range centered around the median value and numerical values falling outside a relatively wide range centered around the same median value. 3 and
A calculation means 4 calculates an index indicating the running condition by dividing the frequency number counted by the counting means 3 and the total number of the large number of numerical values stored in the storage means 2; The vehicle is equipped with a determining means 5 for determining driving conditions such as city driving.

[Effect]

The steering angle signal from the steering angle detection means 1 is sequentially input to the storage means 2, and is stored and updated as a large number of numerical values corresponding to the steering angle. The counting means 3 counts the frequency number remaining after removing the numerical value near the median value and the numerical value near the terminal value from among the large number of numerical values stored in the storage means 2. Next, the calculation means 4 calculates an index J indicating the driving condition from the total number of the large number of numerical values stored in the storage means 2 and the frequency number counted by the counting means 3, and the determination means 5 uses this index J to determine whether the vehicle is traveling on a mountain road or not. Determines driving conditions, such as whether the vehicle is driving in a city area.

Therefore, the steering angle range is divided into a small steering angle range (corresponding to near straight driving) and a biopsy steering angle range (corresponding to driving in a gentle curve).
When driving on a mountain road, there are many curves, but there are few right angle turns, so the frequency of the short steering angle range is higher than the frequency of the small steering angle range. Although there are quite a few, the frequency of large steering angle ranges is extremely low. On the other hand, when driving in a city, there are few curves, but there are many turns at right angles at intersections, so the frequency of small steering angle ranges is extremely high, and the frequency of short steering angle ranges is quite low.
There is also some frequency of large steering angle ranges. The frequency distribution of the steering angle differs between mountain road driving and city driving,
In the former case, it is relatively close to a normal distribution, but in the latter case, compared to a normal distribution, there are more areas near the median and terminal values, fewer areas near the intermediate value (and a large value at the terminal values).

If we take the index J indicating the driving condition according to the present invention and the standard deviation σ, which is the square root of the variance, for these two types of frequency distributions, as shown in the analysis results of the measured data described later, this index J in both driving conditions is The difference is larger than the difference in standard deviation σ.

〔Effect of the invention〕

As mentioned above, in the present invention, the index indicating the driving condition used to determine the driving condition differs more than the standard deviation between mountain roads and urban areas, so it is possible to reliably distinguish between mountain roads and urban areas. Judgment can be made.

〔Example〕

Embodiments of the power steering device will be described below with reference to the drawings. In FIG. 2, the power steering device 10 includes a servo valve 11 connected to a steering handle 18 via a handle shaft 18a, and a power cylinder 12 connected to steering wheels via a linkage mechanism of an enclosure. As is well known, when a manual steering torque is applied to the steering handle 18, the increased steering torque is transmitted to the steered wheels by the power cylinder 12. The power steering device 10 is supplied with pressure fluid by a pump 15 connected to an automobile engine via a drive belt 17.

The solenoid valve 20 controls the assist force of the power cylinder 12 by bypassing the chambers of the power cylinder 12 to which pressure fluid is selectively supplied from the pump 15 via the servo valve 11, and is shown in FIG. Like, valve body 2
A spool 23 that is slidably inserted into an inner hole 22 of the spool 1 and a solenoid 24 are provided. The spool 23 is normally held at the lower end by a spring 25, blocking passages 26, 27 that lead to both chambers of the power cylinder 12. When the solenoid 24 is energized, the spool 23 is attracted according to the current value and is displaced upward against the spring 25, so that the passages 26 and 27 are communicated through the bypass slit 28. It has become so.

As shown in FIG. 4, the flow rate control valve device 30 that controls the discharge flow rate of the pump 15 has a solenoid valve 31 that adjusts the opening degree of the throttle 39, and slides depending on the back and forth pressure of the throttle 39 to open and close the bypass hole 38. A spool valve member 35 is provided for controlling the flow rate of pressurized fluid supplied from the discharge hole 36 of the pump 15 to the servo valve 11 via the delivery port 37. The solenoid valve 31 has a movable spool 32 integrally connected to a valve shaft 32a.
and a solenoid 33, and the movable spool 32 is normally pressed to the left in FIG. 4 together with the valve shaft 32a by a spring 34 to fully open the throttle 39. Then, the solenoid 33 is energized, and as the movable spool 32 is displaced to the right against the spring 34 according to the current value, the valve shaft 32a approaches the throttle 39 and reduces its opening degree, and the spool valve The member 35 is moved to reduce the flow rate of pressure fluid supplied to the servo valve 11.

In FIG. 2, 50 is an electronic control device. This electronic control device 50 has a microprocessor 51, a writable memory (hereinafter simply referred to as RAM) 52, and a read-only memory (hereinafter simply referred to as ROM) 53 as main components, and this microprocessor 51 has an interface 60.
A solenoid drive circuit 61.62 is also connected to control the current applied to the solenoid 24.33 of the electromagnetic valve 20.31. The microprocessor 51 also includes an ink face 47 and a phase determination circuit 4.
A steering angle sensor 40 is connected via 5. The steering angle sensor 40, which constitutes the main part of the steering angle detecting means 1, consists of a rotary plate 41 fixed on the handle shaft 18a and two photoinlubrators 42, 43. The steering wheel steering angle θ is detected based on the signal. Furthermore, microprocessor 5
A vehicle speed sensor 46 is connected to the vehicle speed sensor 1 via an interface 47 . The vehicle speed sensor 46 is composed of a rotating needle connected to the output shaft of the transmission.
The vehicle speed is detected based on the frequency of the pulse signal generated by the vehicle speed sensor 46.

On the other hand, the ROM 53 stores a control pattern for the applied current applied to the solenoid 24.33 of the electromagnetic valve 20.31 as a characteristic map. As shown in FIG. 5, this control pattern includes a control pattern (■) for driving on a mountain road consisting of a combination of characteristics 77 maps IA and IB, and a characteristic map (I).
A control pattern (2) for city driving consisting of a combination of IA and (2)B is prepared, characteristic maps IA and HA are used to drive the solenoid 33 of the flow control valve device 30, and characteristic maps IB and IIB are used to drive the solenoid 33 of the flow control valve device 30, respectively. It is used to drive the solenoid 24 of the electromagnetic valve 20.

In the control pattern I for driving on mountain roads, the current value i to be applied to the solenoid 24 with respect to the numerical value V corresponding to the vehicle speed is
The change characteristics of the current value iA to be applied to the solenoid 33 with respect to the value θ corresponding to the steering angle and the change characteristics of the current value iA corresponding to the steering angle are as shown in the characteristic maps IB and rA, respectively (both essentially increase at a constant rate). As a result, the manual steering torque gradually increases as the vehicle speed increases and as the steering angle increases.As a result, the manual steering torque becomes appropriately large and the road reaction force is accurately controlled. Characteristic maps IB and IA are used to convey information to the driver.
The slope of is selected. This prevents the driver from turning the steering wheel too much when driving on mountain roads, providing a stable steering feel. In addition, in the control pattern H for city driving, the change characteristics of the current value iB with respect to the numerical value ■ are as shown in the characteristic map IrB.
On the other hand, the change characteristics of the current value iA with respect to the numerical value e are as shown in characteristic map IIA (the gradient is smaller than that in characteristic map IA. Therefore, in city driving, the manual steering torque is As the steering angle increases, it becomes as large as when driving on a mountain road, but even if the steering angle increases, it does not become as large as when driving on a mountain road, and this is a characteristic that is suitable for driving in urban areas where the steering wheel is often turned sharply. .

The RAM 52 has a storage area for storing a large number of numerical values θ corresponding to the steering angle θ of the steering wheel, and the ROM 53 stores the numerical values θ corresponding to the steering angle θ detected by the steering angle sensor 40 at predetermined intervals. At the same time, the number of frequencies of the numerical values excluding the numerical value near the median value and the numerical value near the terminal value among the large number of numerical values e is counted, and the counted frequency number and the total number of numerical values e are calculated. An index J indicating the driving condition (hereinafter simply referred to as mountain road index) is calculated, and it is determined from this mountain road index J whether the vehicle is driving on a mountain road or in a city area, and based on the determination result, the solenoid valve A control program for selecting a control pattern for the currents iA and iB applied to the 31.20 is stored.

Figures 6 (C) and 7 (C) show the frequency distribution of the numerical value e corresponding to the steering angle θ based on actual measurement data described later. The frequency distribution is as shown in FIG. 6(C), and since there are few curves in city driving, but there are many right angle turns at intersections, the frequency distribution is as shown in FIG. 7(C). Therefore,
Mountain road index J obtained during execution of the control program
is slightly larger when driving on a mountain road than when driving in a city, and the driving state of the car is automatically determined by subsequent execution of the control program, and from the result, the control pattern I shown in Fig. 5 is determined. , If can be selected.

Next, the control operation of the steering force control device will be explained with reference to the flowcharts shown in FIGS. 8 and 9.

When the car is running, a constantly changing steering angle signal detected by the steering angle sensor 40 as a numerical value e corresponding to the steering angle θ is manually inputted to a counter (not shown) via a phase determination circuit 45, and A numerical value (■) corresponding to the vehicle speed detected by the vehicle speed sensor 46 is also input to a counter (not shown).

The microprocessor 51 executes a processing operation based on a program at the same time that an interrupt signal is input every predetermined mileage. First, in step 100 of FIG. 8, the steering angle value θ stored in the counter is read, and then in step 101 the sampling number counter value n is compared with the set number N. Immediately after the start of running, the number of samplings is small and n<N, so the program goes to step 1.
02, 1 is added to the sampling number counter value n, and in the following step 103, the absolute value of the numerical value e is set in the nth area Mn of the storage area of the RAM 52.

When the number of samples n increases and reaches the set number N, the program proceeds from step 101 to step 104, and the set value of area M2 is transferred to area M1, the cent value of area M3 is transferred to area M2, and so on. The absolute value of the latest (nth) numerical value θ is set in the last area M, and the stored contents are thus updated. In this state, the sampling number counter value remains n (=N).

In step 105 following step 103 or 104, a sampling number counter value n is initialized in the read counter H, and in subsequent step 106, the value MH of the Hth area is compared with two set values B and C. The set values B and C are respectively a value slightly larger than the median value (i.e. 0) of a series of numerical values θ corresponding to the steering angle θ, and a value smaller than the absolute value of the terminal value, and in the numerical example described later, B=
3, C=12. In step 106, 86M
)-1≦C, directly, and B≦Ml-1≦C
If so, 1 is added to the frequency counter value D (initialized to O each time the program is executed) in step 107, and the program proceeds to step 108, where 1 is subtracted from the read counter value H. In the following step 109, the read counter value H is compared with the numerical value 0, and the above steps 106 to 108 are repeated until H-h<O, and H=
If it becomes O, the program proceeds to the next step 110. By repeating steps 106 to 108, the frequency counter value becomes the frequency of the values Mn of each storage area where B:5Mn≦C.

In the following step 110, a mountain road index J is calculated using the following equation.

J = D / n Subsequently, in step 111, the mountain road index J and the reference value E are determined.
Distinguish the size of the If J≧E, the numerical value e is shown in Figure 6 (
If the frequency distribution is like bl, it is determined that the driving is on a mountain road, and if J≧E, then the numerical value θ is as shown in Fig. 7 (bl
The frequency distribution is as follows, and it is determined that the vehicle is driving in an urban area. If J≧E, the running determination flag F is set to 1 in step 112, and if J≧E, step 11
3, the running determination flag F is set to O. The reference value E is determined based on the frequency distribution of the numerical value θ in each driving state, and in the case of the numerical example described later, E=0.3.

Note that the equation in step 110 may be J=D/N. In this way, if the number of samples n is small, the mountain road index J will be small, so immediately after the start of driving, it is always determined that the vehicle is driving in an urban area, and as the number of samples n approaches N, the actual driving condition is determined. . This prevents the running determination flag F from being changed frequently immediately after the start of running due to the small number of samples.

When step 112 or 113 is completed, the microprocessor 51 stops executing the program according to the flowchart of FIG. 8 until the next interrupt signal is input.
An interrupt signal is output to start execution of the program according to the flowchart shown in the figure.

A numerical value ■ corresponding to the vehicle speed and a numerical value e corresponding to the steering angle stored in each counter in step 200 of FIG.
is read, and in the next step 201, the running determination flag F is read. In the following step 202, the value of the driving determination flag F is determined, and if F=1, the program proceeds to steps 203 and 204, and based on the values e and V from the characteristic maps IA and IB for driving on mountain roads in the ROM 53. Applied currents iA, iB are searched and applied to the solenoids 33.24 of the solenoid valves 31.20, respectively. In step 202, if F=1, the program proceeds to steps 205 and 206 and stores the characteristic map IIA for city driving in the ROM 53.

Applied currents iA and iB are searched based on the values θ and ■ from nB, and the solenoid 33 of the solenoid valve 31 and 20 is searched.
．． 24. When step 204 or 206 is completed, the microprocessor 51 stops executing the program according to the flowchart of FIG. 9 until the next interrupt signal is input.

Thereafter, the microprocessor 51 repeatedly executes the programs according to each of the flowcharts described above each time an interrupt signal is output every predetermined distance traveled, and sets the steering force according to the traveling state of the vehicle.

Figures 6 (a) and 7 (81 are measurement data (sampling number = 130) obtained when actually driving on a mountain road and in a city area, outputting an interrupt signal every 10 m, respectively,
This figure shows the value θ (unit: twice) which is 1/18 of the steering angle θ of the handle shaft 18a at the position of cumulative distance C+D (unit: 10 m). Figures 6(C) and 7(C) are frequency distribution histograms in which the values θ in Figures 6(al) and 7(a) are divided into 5 degrees, respectively. FIG. 7 (bl is a frequency distribution histogram of absolute values of values θ divided into 5 degree increments.

As mentioned above, by comparing the respective frequency distribution histograms, the following becomes clear. In other words, when driving on a mountain road, there are many curves, but there are few right angle turns, so Figure 6 (bl and (C)
), the frequency of the medium steering angle range is considerably higher than the frequency of the small steering angle range, but the frequency of the large steering angle range is almost non-existent. On the other hand, when driving in a city, there are few curves, but there are many right angle turns at intersections, so as shown in Figure 7 (b) and (C1), the frequency of small steering angle ranges is extremely high.
Although the frequency in the medium steering angle range decreases rapidly, the frequency in the large steering angle range is also considerable. As described above, there is a clear difference in the frequency distribution of the numerical value e between mountain road driving and city driving.

Therefore, in Figure 6 (C1) and Figure 7 (C1), α is within a relatively narrow range of −B<θ<B near the median value, and T is within a relatively narrow range of θ<−C and C<θ near the terminal value. Find the frequency number of the number θ in the range β excluding , and divide it by the total frequency number N to find the mountain road index J.
B=3 and C=12. Also, for comparison, Figure 6 (
8) and the standard deviation σ obtained from Figure 7 (al).

DJ σ Mountain road driving 70 0.538 4.70 City driving 18 0.138 5.28 The difference in mountain road index J between mountain road driving and city driving (ratio: 3.90) is the difference in standard deviation σ (ratio: 1/1.12), and therefore, the discrimination between both running states can be made more reliably by using the mountain road index J. Also, in this case,
It is appropriate to set the reference value for discrimination to 0.3.

The above calculation of the mountain road index J is shown in Figure 6 (bl and Figure 7 tb).
) can be similarly performed using the frequency distribution histogram of the absolute value of the numerical value θ, and the program according to the flowchart shown in Figure 8 above calculates the mountain road index J using the absolute value of the numerical value θ. It is something to do.

Although this embodiment is applied to steering force control of a power steering device, the present invention is not limited to a steering device, but can also be applied to vehicle height control, etc.

Further, in this embodiment, the judgment is made using one reference value E, but a plurality of reference values are set at appropriate intervals, and each characteristic map is stored in the ROM 53 for each range divided by the reference value. Alternatively, the characteristic map may be prepared in accordance with the value of the mountain road index J and selected. If you do this,
It is possible to avoid a sudden change from the steering force characteristics on a mountain road to the steering force characteristics in an urban area.

In this embodiment, the mountain road index J is obtained by dividing the frequency number of the numerical value θ within the range β by the total frequency number n, but the reciprocal number may be used as the mountain road index. Furthermore, although the mountain road index J is directly compared with the reference value E for discrimination, the mountain road index J may be further subjected to appropriate calculations and then compared and discriminated.

[Brief explanation of drawings]

The drawings show an embodiment of the vehicle running state determination device according to the present invention, in which Fig. 1 is an overall configuration diagram of the invention, Fig. 2 is an overall block diagram, and Fig. 3 is a vertical cross-section of a solenoid valve for bypass control. 4 is a vertical sectional view of a flow rate control valve device for controlling the discharge amount, FIG. 5 is a diagram graphically showing the applied current to the solenoid of the electromagnetic valve, and FIGS. 6 (a) to (c) Based on actual measurement data when driving on mountain roads! a) is the actual measured value, Tbl is the frequency distribution histogram, (C) is the frequency distribution histogram of the absolute value, the seventh
Figures (a) to (C) are actual measurement data for city driving, and Figures 6 (corresponding to al to tc+), Figures 8 and 9 are flowcharts showing control programs. Explanation of symbols 1...Steering angle detection means, 2...Storage means, 3...
Counting means, 4... Calculation means, 5... Judgment means, 20
...Steering handle.

Claims (1)

[Claims] A driving state determination device for an automobile equipped with a steering wheel includes a steering angle detecting means for detecting a steering angle and generating a steering angle signal, and a plurality of steering angle detecting means for sequentially inputting the steering angle signal at predetermined intervals and corresponding to the steering angle. storage means for simultaneously storing the numerical values of and updating the stored contents, and a numerical value within a relatively narrow range centered around the median value from the large number of numerical values stored in the storage means, and a numerical value in the vicinity of the same median value. a counting means for counting the remaining frequency numbers after removing numbers outside a relatively wide range centered on , and between the frequency numbers counted by this counting means and the total number of the large number of numbers stored in the storage means. calculation means for calculating an index indicating the running state by dividing the
A driving state determination device for a motor vehicle, comprising a determining means for determining a driving state such as driving on a mountain road or in a city area using this index.