JPH0785992B2 - Vehicle running condition determination device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a traveling state determination device used when controlling a steering force or a vehicle height roughly according to a traveling state of an automobile.

[Prior art]

Conventionally, it is usual to judge the running state of a vehicle based on the vehicle speed.The result of this judgment indicates that the steering force is light in the low speed range and heavy in the high speed range. There is something to control.

[Problems to be solved by the invention]

In the conventional technique for determining the traveling state based on such a vehicle speed, for example, in the case of the above-described assist force control, the control pattern of the assist force with respect to the vehicle speed, the steering angle, etc. becomes constant, and both in the case of mountain road traveling and in the city area traveling. The control pattern of the assist force does not change, and there is a problem that the steering force suitable for each traveling state cannot be obtained. Similar problems also exist in vehicle height control of automobiles, and also in the case of suspension hardness control.

In order to solve this problem, a method has been developed in which a plurality of control patterns for assisting force are provided in steering force control, and the control pattern is manually selected as appropriate according to the driver's preference or traveling state. Then, in order to eliminate the trouble of manual selection, it is possible to automatically determine the traveling state and select the control pattern. For this purpose,
The present applicant has previously filed an application for Japanese Patent Application No. 59-112303 (Japanese Examined Patent Publication No. 3-2114), and has proposed to judge the running state of an automobile based on the dispersion state of steering angle signals. However, as described in the same application, although it is possible to make a distinction between high-speed traveling and mountain road traveling according to the dispersed state of the steering angle signal, the dispersed state is similar between urban traveling and mountain road traveling. Therefore, it was difficult to make a distinction between the two without fail.

Further, Japanese Patent Application Laid-Open No. 59-59574 discloses a technique for judging mountain road traveling and city traveling based on an average steering amount per unit time.

However, as described in JP-A-59-59574, when the average steering amount per unit time is obtained, the average steering amount is affected by the speed, and even if the vehicle travels on the same road, the difference in speed may occur. However, there was a difference in the required average steering amount, and there was a problem that it was not possible to judge whether it was traveling on a mountain road or in an urban area.

According to the present invention, a steering angle is fetched at a predetermined distance interval, a plurality of steering angles are stored at the same time, and an average value of absolute values of the plurality of steering angles is reliably discriminated between mountain road traveling and urban traveling. It is a thing.

[Means for solving problems]

To this end, the vehicle running state determining device according to the present invention is, as shown in FIG. 1, a vehicle running state determining device including a steering handle 20, and the steering handle 20 according to the steering amount of the steering handle 20. Steering angle detecting means 1 that generates a positive steering angle signal when the steering wheel is steered to one side and a negative steering angle signal when the steering wheel is steered to the other side, and the steering angle signals are sequentially arranged at predetermined distance intervals. An arbitrary number of numerical values corresponding to the steering angle are stored at the same time, and when the numerical value reaches the arbitrary number, the latest numerical value corresponding to the steering angle is taken in place of the oldest numerical value of the arbitrary number. A storage means 2 for updating the stored contents, a calculation means 3 for calculating an average value of absolute values of the arbitrary number of numerical values stored in the storage means, and when the average value is larger than a predetermined reference value. There is a lot of curves, but it is judged that the road is a mountain road with few turns at a right angle. Be prepared.

[Action]

A steering angle signal is sequentially input from the steering angle detection means 1 each time the vehicle travels a predetermined distance, and the storage means simultaneously stores a large number of arbitrary numbers corresponding to the sequentially input steering angle signals. When the number is reached, the stored value is updated by taking in the latest numerical value corresponding to the steering angle instead of the oldest numerical value. The calculation means 3 calculates the average value of the absolute values from the large number of numerical values stored in the storage means 2.

As a result, the average value of the steering angle can be accurately obtained regardless of the speed, and the average value of the steering angle that matches the current driving situation can be obtained by calculating the average value from many steering angles. The influence of each steering angle is reduced so that the judgment does not change frequently.

When the average value is greater than a predetermined reference value, the determining means 4 determines that the road is a mountain road with many curves but with few turns at a right angle, and when the average value is less than the reference value, the vehicle is straight ahead. It is judged to be driving in urban areas with few curves but with many turns at right angles.

Therefore, the range of the steering angle is a small steering angle range (corresponding to near straight running) and a middle steering angle range (corresponding to gentle curve running).
And a large steering angle range (corresponding to tight curve running), there are many curves on mountain roads, but there are few turns at right angles, so the frequency of the medium steering angle range is less than the frequency of the small steering angle range. There are many, but the frequency of the large steering angle range is extremely low. On the other hand, in urban driving, there are few curves, but there are many turns at right angles at intersections, so the frequency in the small steering angle range is extremely high, and the frequency in the medium steering angle range is considerably low.
There is some frequency in the large steering angle range. In this way, the frequency distribution state of the steering angle is different between mountain road driving and city driving,
In the former case, the distribution is relatively close to the normal distribution, but in the latter case, the median value and the terminal value vicinity are larger, the median value vicinity is smaller, and the terminal value is larger than the normal distribution.

Taking the mean value X of absolute values and the standard deviation σ (using standard deviation instead of variance in order to match the dimensions) for these two types of frequency distributions, the mean value X is the value of the value when traveling on mountain roads. The value of the standard deviation σ is smaller than that in the case of driving in an urban area, and the standard deviation σ is smaller than the value of the latter. As described above, regarding the steering angle frequency distribution in mountain road traveling and urban area traveling, the average value X of the absolute values and the standard deviation σ show opposite tendencies, and as shown in the analysis result of the actual measurement data described below, in both traveling states. The difference in the average value X is larger than the difference in the standard deviation σ.

〔The invention's effect〕

As described above, in the present invention, by inputting the steering angle for each predetermined distance, the difference in the average value of the absolute values of the steering angle becomes clearer between the case of a mountain road and the case of an urban area, regardless of the speed. Accurate steering angle can be obtained.

Also, by storing any number of steering wheels at the same time and storing the latest steering angle instead of the oldest steering angle when the number of steering wheels reaches the arbitrary number, the average value of the steering angle that is in the current driving situation can be obtained and input. The influence of each steering angle can be reduced.

As a result, the accuracy of the numerical value of the average of the absolute values of the steering angles is improved, and it is possible to reliably determine whether the road is a mountain road or an urban area.

〔Example〕

Embodiments of the power steering apparatus will be described below with reference to the drawings. In FIG. 2, the power steering apparatus 10 is a steering wheel shaft.
Servo valve 1 connected to the steering wheel 18 via 18a
1 and a power cylinder 12 connected to a steering wheel through a link mechanism (not shown).
When a manual steering torque is applied to 18, the steering torque increased by the power cylinder 12 is transmitted to the steered wheels. The power steering apparatus 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 by the power cylinder 12 by bypassing between the two chambers of the power cylinder 12 to which the pressure fluid is selectively supplied from the pump 15 via the servo valve 11, and is shown in FIG. As described above, the spool 23 slidably fitted in the inner hole 22 of the valve body 21 and the solenoid 24 are provided. The spool 23 is normally held at the lower end by a spring 25, and blocks communication between the passages 26 and 27 communicating with both chambers of the power cylinder 12. Then solenoid 2
When the current is applied to the spool 4, the spool 23 is attracted according to the current value, is displaced upward against the spring 25, and passes through the passage.
26 and 27 are communicated with each other via a bypass slit 28.

The flow rate control valve device 30 for controlling the discharge flow rate of the pump 15 includes a solenoid valve 31 for adjusting the opening degree of the throttle 39, as shown in FIG.
A spool valve member 35 for controlling the flow rate of the pressure fluid supplied to the servo valve 11 from the discharge hole 36 of the pump 15 through the delivery port 37 by sliding by the front and rear pressure of the throttle 39 to open and close the bypass hole 38 is provided. ing. The solenoid valve 31 includes a movable spool 32 and a solenoid 33, which are integrally connected to a valve shaft 32a, and the movable spool 32 is normally pressed by a spring 34 together with the valve shaft 32a to the left in FIG. . Then, as the solenoid 33 is energized and the movable spool 32 is displaced rightward against the spring 34 according to the current value, the valve shaft 32a approaches the throttle 39 to reduce its opening degree, and the spool valve The member 35 is moved to reduce the supply flow rate of the pressurized fluid to the servo valve 11.

In FIG. 2, 50 is an electronic control unit. The electronic control unit 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 constituent elements. The microprocessor 51 includes an interface 60 and a solenoid. The drive circuits 61 and 62 are connected to control the current applied to the solenoids 24 and 33 of the solenoid valves 20 and 31, respectively. Further, the steering angle sensor 40 is connected to the microprocessor 51 via an interface 47 and a phase determination circuit 45. Steering angle sensor 40 which is a main part of the steering angle detecting means 1.
Is composed of a rotary plate 41 fixed on the handle shaft 18a and two photo interrupters 42 and 43, and detects the steering angle θ of the steering wheel by a signal from the photo interrupters 42 and 43. Further, a vehicle speed sensor 46 is connected to the microprocessor 51 via an interface 47. The vehicle speed sensor 46 is composed of a tachometer connected to the output shaft of the transmission, and detects the vehicle speed from the frequency of the pulse signal generated by the vehicle speed sensor 46.

On the other hand, the ROM 53 stores a control pattern of an applied current applied to the solenoids 24, 33 of the solenoid valves 20, 31 as a characteristic map. As the control pattern, as shown in FIG. 5, a mountain road traveling control pattern I composed of a combination of characteristic maps IA and IB, and an urban traveling control pattern II composed of a combination of characteristic maps II A and II B. Is prepared,
Characteristic maps IA and II A are used to drive the solenoid 33 of the flow control valve device 30, and characteristic maps IB and II are used.
B is used to drive the solenoid 24 of the solenoid valve 20.

In the control pattern I for mountain road traveling, the current value i B to be applied to the solenoid 24 for the numerical value V corresponding to the vehicle speed
And the change characteristic of the current value i A to be applied to the solenoid 33 with respect to the numerical value Θ with respect to the steering angle of the steering wheel are set so as to increase at an essentially constant rate as shown in characteristic maps IB and IA, respectively. Has been done. As a result, the manual steering torque gradually increases as the vehicle speed increases and the steering angle increases. Then,
The slopes of the characteristic maps IB and IA are selected so that the manual steering torque becomes moderately large and the road surface reaction force is accurately transmitted to the driver. As a result, it is possible to prevent the steering wheel from being excessively turned when traveling on a mountain road, and to obtain a stable steering feeling. Further, in the control pattern II for city driving, the change characteristic of the current value i B with respect to the numerical value V is almost the same as the characteristic map IB as shown in the characteristic map II B, while the current value i A with respect to the numerical value Θ. The change characteristics of
As shown in the characteristic map II A, the gradient is smaller than that in the characteristic map IA. Therefore, in city driving, the manual steering torque becomes as large as the vehicle speed as in the case of mountain road driving, but it does not become as large as in the mountain road driving even if the steering angle increases, and the steering wheel becomes larger. This characteristic is suitable for city driving, which is often cut.

The RAM 52 has a storage area for storing a large number Θ corresponding to the steering angle θ of the steering wheel, and further, the ROM 53 stores the numerical value Θ corresponding to the steering angle θ detected by the steering angle sensor 40 at predetermined intervals in the RAM 52. And store it in sequence and update it,
The average value X of the absolute values is calculated from the many numerical values Θ,
From the average value X, it is determined whether the vehicle is in a mountain road traveling state or an urban area traveling state, and the control pattern of the currents i A, i B applied to the solenoid valves 31, 20 is selected from the determination result. A control program is stored.

FIGS. 6 (c) and 7 (c) show the frequency distribution of the numerical value Θ corresponding to the steering angle θ based on the actual measurement data described later, and there are many curves on mountain roads, but there are few curves at right angles. The frequency distribution is as shown in FIG. 6 (c), and in urban driving there are few curves, but there are many turns at intersections, so the frequency distribution is as shown in FIG. 7 (c). Therefore, the average value X obtained during the execution of the control program becomes larger in the case of mountain road traveling than in the city traveling, and the traveling state of the vehicle is automatically changed by the subsequent execution of the control program. The control patterns I and II shown in FIG. 5 can be selected from the results.

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

In the running state of the vehicle, the momentarily changing steering angle signal detected by the steering angle sensor 40 as a numerical value Θ corresponding to the steering angle θ is input to a counter (not shown) via the phase determination circuit 45, and The numerical value V corresponding to the vehicle speed detected by the vehicle speed sensor 46 is also input to the counter (not shown).

The microprocessor 51 executes the processing operation based on the program at the same time when the interrupt signal is input at a predetermined interval. First, in step 100 of FIG. 8, the numerical value Θ of the steering angle stored in the counter is read, and subsequently, 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 proceeds to step 102, where 1 is added to the sampling number counter value n, and in the following step 103, the nth area Mn
Is set to the absolute value of the numerical value Θ.

When the sample number n increases and reaches the set number N, the program proceeds from step 101 to step 108,
Set value of area M2 is set to area M1, set value of area M3 is set to area
To M2, is sequentially shifted., Absolute value of the numerical Θ latest (n-th) at the end of region M _N is set, thus stored data is updated. In this state, the sampling number counter value is n (= N) or less.

In step 104 following step 103 or 108, the average value X of the absolute values of the steering angle value Θ is calculated by the following equation.

Then, at step 105, the magnitude of the average value X and the reference value K is discriminated. If X> K, the numerical value Θ is shown in FIG. 6 (b).
It is determined that the vehicle is traveling on a mountain road, and if X> K, the value Θ has a frequency distribution as shown in FIG. 7B and that it is traveling in the city. It If X> K, the travel determination flag F is set to 1 in step 106, and if X> K, the travel determination flag F is set to 0 in step 107. The reference place K is determined by the frequency distribution of the numerical value Θ in each traveling state, and K = 3 in the numerical example described later. Further, according to the equation of step 104, the average value X is small if the number of sampling times n is small, so it is always determined that the vehicle is traveling in the urban area immediately after the start of traveling,
If the number of sampling times n approaches N, the actual traveling state is determined. By doing so, it is possible to prevent the travel determination flag F from being frequently replaced immediately after the start of travel due to the small number of samples.

When step 106 or 107 is completed, the microprocessor 51 stops the execution of the program according to the flowchart of FIG. 8 until the next interrupt signal is input, and starts the execution of the program according to the flowchart of FIG. Is output.

In step 110 of FIG. 9, the numerical value V corresponding to the vehicle speed and the numerical value Θ corresponding to the steering angle stored in the respective counters are read, and in the next step 111 the traveling determination flag F is read. In the following step 112, the value of the traveling determination flag F is determined, and if F = 1, the program proceeds to step 113.
Proceed to steps 114 and 114, and a special map I for running on a mountain road in ROM53.
The applied currents i A and i B are searched from A and IB based on the numerical values Θ and V and applied to the solenoids 33 and 24 of the solenoid valves 31 and 20, respectively. If F = 1 in step 112, the program proceeds to steps 115 and 116, and the applied currents i A, i B are searched from the characteristic maps II A, II B for traveling in the city in the ROM 53 based on the numerical values Θ and V. , Are applied to the solenoids 33, 24 of the solenoid valves 31, 20, respectively. When step 114 or 116 is completed, the microprocessor 51 stops the execution of the program according to the flowchart of FIG. 9 until the next interrupt signal is input.

After that, each time the interrupt signal is output with a predetermined feeling, the microprocessor 51 repeatedly executes the above steps to set the steering force according to the running state of the vehicle.

Figure 6 (a) and Figure 7 (a) are the measured data (sampling frequency: 130) when actually traveling on a mountain road and an urban area and outputting an interrupt signal every 10 m, and the cumulative distance. It shows a value Θ (unit: degree) which is 1/18 of the steering angle θ of the handle shaft 18A at the position of C + D (unit: 10 m). FIGS. 6 (c) and 7 (c) are frequency distribution histograms obtained by dividing the value Θ of FIGS. 6 (a) and 7 (a) by 5 degrees, and FIG. 6 (b). 7 and FIG. 7 (b) are frequency distribution histograms of absolute values of the value Θ divided every 5 degrees.

As described above, the following is found by comparing the frequency distribution histograms. That is, since there are many curves on mountain roads, but there are few turns at right angles, the frequency in the middle steering angle range is less than that in the small steering angle range, as shown in FIGS. 6 (b) and (c). However, there is almost no frequency in the large steering angle range. On the other hand, when driving in urban areas, there are few curves, but at intersections, there are many turns at right angles, so Figure 7 (b)
As shown in (c) and (c), the frequency of the small steering angle range is extremely high, and the frequency of the medium steering angle range sharply decreases, but the frequency of the large steering angle range also considerably exists. Thus, there is a clear difference in the frequency distribution state of the numerical value Θ between mountain road driving and city driving.

Next, the average value X and the standard deviation σ of the absolute values of the numerical value Θ are obtained from the actual measurement data of FIGS. 6 (a) and 7 (a), as follows.

X σ Mountain road driving 3.63 4.70 Urban driving 2.26 5.28 Difference in average value X between mountain driving and urban driving (ratio:
1.61) is larger than the difference in the standard deviation σ (ratio: 1 / 1.12), so that the determination of both running states can be made more reliably based on the magnitude of the average value X. Further, in this case, it is appropriate that the reference value K for determination is 3.

The average value X and the standard deviation σ are opposite in magnitude relation between mountain road traveling and urban traveling, but this is due to the existence of the frequency of the large steering angle range in urban traveling.

Although the present embodiment is applied to the steering force control of the power steering device, the present invention is not limited to the steering device and can be applied to vehicle height control and the like.

Further, in the present embodiment, the determination is made by using one reference value K, but a plurality of reference values are set at appropriate intervals and each characteristic map is set for each range separated by the reference value.
It may be prepared in the ROM 53 and the characteristic map may be selected according to the value of the average value X. By doing so, it is possible to avoid a sudden change from the steering force characteristic of the mountain road to the steering force characteristic of the city area.

Further, in the present embodiment, the average value X is directly compared with the reference value K for determination, but the average value X is further subjected to appropriate calculation (for example, division by standard deviation σ) and then compared and determined. Good.

[Brief description of drawings]

The drawings show an embodiment of a vehicle running condition determining apparatus according to the present invention. FIG. 1 is an overall configuration diagram of the present invention, FIG. 2 is an overall block diagram, and FIG. 3 is a longitudinal section of a solenoid valve for bypass control. FIG. 4 is a longitudinal sectional view of a flow rate control valve device for controlling the discharge amount, FIG. 5 is a diagram showing a current applied to a solenoid of a solenoid valve, and FIGS. 6 (a) to 6 (c). Is the measured data when traveling on a mountain road, (a) is the measured value, (b) is the frequency distribution histogram, (c) is the absolute value frequency distribution histogram, and
Figures (a) to (c) are actual measurement data when driving in urban areas and correspond to Figures 6 (a) to (c), and Figures 8 and 9 are flowcharts showing the control program. DESCRIPTION OF SYMBOLS 1 ... Steering angle detection means, 2 ... storage means, 3 ... calculation means, 4 ... determination means, 20 ... steering wheel.

 ─────────────────────────────────────────────────── --Continued from the front page Judging panel for referee Kunihiko Takahashi Referee Toshiaki Tsukiyama Referee Katsutoshi Shiozawa (56) References JP59-59574 (JP, A) JP60-151180 (JP, A) Japanese Patent Publication 3-2114 (JP, B2)

Claims (1)

[Claims] 1. A vehicle running condition determination device having a steering wheel, wherein a positive steering angle signal is generated when the steering wheel is steered to one side according to the steering amount of the steering wheel, and the steering wheel is steered to the other side. Steering angle detecting means for generating a negative steering angle signal, and sequentially inputting this steering angle signal at predetermined distance intervals to store an arbitrary number of numerical values corresponding to the steering angle at the same time, and the numerical value is an arbitrary number. When the number of times reaches, the storage means for fetching a numerical value corresponding to the latest steering angle instead of the oldest numerical value of the arbitrary number and updating the stored contents, and the arbitrary number of the numerical values stored in the storage means. When the average value of the absolute value of the numerical value is calculated, and when this average value is larger than a predetermined reference value, it is determined that the road is a mountain road traveling with many curves but few turns at right angles. Straight running many curves when serial smaller than the reference value is small but car traveling state determining device including a determination unit and large urban driving be bent at a right angle.