JPH0581466B2 - - Google Patents

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 vehicle has usually been determined based on the vehicle speed, and based on this determination result, the power steering system can be 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 the assist force.

[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 suitable for each driving condition could not be obtained. Similar problems exist in vehicle height control, suspension stiffness control, etc. 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 present applicant previously filed Japanese Patent Application No. 112303/1983, proposing to determine the driving state of an automobile based on the dispersed state of the steering angle signal. 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 similar between city driving and mountain road driving. Therefore, it was 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, the vehicle running state determination device according to the present invention has a steering wheel 20 as shown in FIG.
A driving state determination device for an automobile includes a steering angle detecting means 1 that detects a steering angle and generates a steering angle signal, and a steering angle detecting means 1 that detects a steering angle and generates a steering angle signal, and a steering angle detecting means 1 that sequentially inputs the steering angle signal at predetermined time intervals to determine the steering angle. Steering angle storage means 2 for simultaneously storing a large number of corresponding numerical values and updating the stored contents, a first threshold value for classifying a small steering angle range and a medium steering angle range, and a medium steering angle range and a large steering angle. A threshold storage means M stores a second threshold value for classifying the range, and a first threshold value stored in the threshold storage means M is selected from the large number of numerical values stored in the steering angle storage means 2. A counting means 3 for counting the frequency of numerical values greater than a threshold value and less than a second threshold value, and between the frequency number counted by this counting means 3 and the total number of the large number of numerical values stored in the storage means 2. calculation means 4 for calculating an index indicating the running state by dividing;
This index is used to determine whether the driving condition is driving on a mountain road where there are many curves but few turns at right angles, or whether driving is driving on a city road where there are many straight lines and few curves but many turns at right angles. It is what it is.

[Effect]

The steering angle signal from the steering angle detection means 1 is sequentially input to the counting means 2 over time, and is stored and updated as a large number of numerical values corresponding to the steering angle. The counting means 3 counts the number of frequencies of numerical values stored in the threshold storage means M which are greater than or equal to the first threshold value and less than or equal to the second threshold 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 running state 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,
The determining means 5 uses this index J to determine whether the vehicle is driving on a mountain road with many curves but rarely turning at right angles, or driving in a city area where the vehicle mostly travels straight and has few curves but often turns at right angles.

Therefore, the range of the steering angle is determined by the first threshold value and the second threshold value as a small steering angle range (corresponding to near straight driving), a medium steering angle range (corresponding to driving in a gentle curve), When divided into large steering angle range (corresponding to driving on tight curves), there are many curves when driving on mountain roads, but there are few right angle turns, so the frequency of medium steering angle range is quite low compared to the frequency of small steering angle range. Although it exists, 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 right-angle turns at intersections, so the frequency of small steering angle ranges is extremely high, the frequency of medium steering angle ranges is quite low, and the frequency of large steering angle ranges is also somewhat present. do. The frequency distribution of steering angles is thus different between mountain road driving and city driving.

If we take the index J indicating the driving state 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 states The difference in is larger than the difference in standard deviation σ.

〔Effect of the invention〕

As mentioned above, in the present invention, the difference in the index indicating the driving condition used for determining the driving condition between mountain roads and urban areas is larger than the standard deviation, so it is possible to reliably distinguish between mountain roads and urban areas. The determination can be made separately.

〔Example〕

Embodiments of the power steering device will be described below with reference to the drawings. In FIG. 2, the power steering device 1
0 is the steering wheel 1 via the handle shaft 18a.
8, and a power cylinder 12 connected to the steering wheel via a link mechanism (not shown).
When manual steering torque is added to the steering wheel 8, the increased steering torque is transmitted to the steered wheels by the power cylinder 12. Power steering device 10
is supplied with pressurized fluid by a pump 15 connected to the 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.
As shown in the figure, the valve body 21 includes a spool 23 that is slidably inserted into an inner hole 22 of a valve body 21, and a solenoid 24. The spool 23 is normally held at the lower end by a spring 25 and blocks communication between passages 26 and 27 that communicate with 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 via the bypass slit 28. It is becoming more and more like this.

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. and pump 1
The servo valve 11 is provided with a spool valve member 35 that controls the flow rate of the pressure fluid supplied from the discharge hole 36 of No. 5 to the servo valve 11 via the delivery port 37. Solenoid valve 31
is a movable spool 32 integrally connected to a valve shaft 32a.
and a solenoid 33, and the movable spool 32 is
Normally, the spring 34 presses the valve shaft 32a together with the valve shaft 32a toward the left in FIG. 4 to fully open the throttle 39. Thus, the solenoid 33 is energized, and the movable spool 32 moves the spring 3 according to the current value.
4, the valve shaft 32a approaches the throttle 39 and reduces its opening degree, moving the spool valve member 35 to reduce the flow rate of pressure fluid supplied to the servo valve 11. It is.

In FIG. 2, 50 is an electronic control device. This electronic control device 50 is a microprocessor 51
and writable memory (hereinafter simply referred to as RAM)
52 and a read-only memory (hereinafter simply referred to as ROM) 53 as main components, this microprocessor 51 is connected to an interface 60 and solenoid drive circuits 61, 62, and operates the solenoids 24, 33 of the electromagnetic valves 20, 31. It is designed to control the current applied to the Further, a steering angle sensor 40 is connected to the microprocessor 51 via an interface 47 and a phase determination circuit 45. The steering angle sensor 40, which constitutes the main part of the steering angle detection means 1, includes a rotary plate 41 fixed on the handle shaft 18a, two photo interrupters 42,
43, such photo interrupter 42,
The steering wheel steering angle θ is detected by a signal from 43. Furthermore, 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 is adapted to detect the vehicle speed based on the frequency of a pulse signal generated from the vehicle speed sensor 46.

On the other hand, the ROM 53 stores control patterns for applied currents applied to the solenoids 24 and 33 of the electromagnetic valves 20 and 31 as a characteristic map. As this control pattern, as shown in FIG. 5, there are prepared a control pattern for driving on mountain roads, which is a combination of characteristic maps A and B, and a control pattern for driving in urban areas, which is a combination of characteristic maps A and B. Characteristic maps A and A are used to drive the solenoid 33 of the flow rate control device 30, and characteristic maps B and B are used to drive the solenoid valve 2, respectively.
It is used to drive the solenoid 24 of 0.

In the control pattern for driving on mountain roads, the change characteristics of the current iB to be applied to the solenoid 24 with respect to the value V corresponding to the vehicle speed and 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 wheel steering angle are as follows. , as shown in characteristic maps IB and IA, respectively, are set to essentially increase at a constant rate. As a result, the manual steering torque increases as the vehicle speed increases.
Moreover, it gradually becomes larger as the steering angle increases.
Therefore, the gradients of the characteristic maps B and B are selected so that the manual steering torque is appropriately large and the road reaction force is accurately transmitted to the driver.
This prevents the steering wheel from being turned too much when driving on mountain roads, and provides a stable steering feel. In addition, in the control pattern for city driving, the change characteristics of the current value iB with respect to the numerical value V are as follows:
As shown in characteristic map B, the current value iA for numerical value Θ is approximately the same as characteristic map B.
As shown in the characteristic map, the change characteristic of A has a smaller gradient than that of characteristic map A. Therefore, when driving in a city, the manual steering torque increases as the vehicle speed increases, to the same extent as when driving on a mountain road.
Even if the steering angle increases, it is not as large as when driving on mountain roads, making it a characteristic 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 a numerical value Θ corresponding to the steering angle θ detected by the steering angle sensor 40 at predetermined intervals.
While sequentially storing and updating in RAM 52,
Among the many numbers Θ, the frequency of the numbers excluding the numbers near the median and the numbers near the end values is counted, and the counted frequency and the total number of numbers Θ are used as an index (hereinafter simply referred to as (referred to as mountain road index)
J is calculated, and based on this mountain road index J, it is determined whether the vehicle is running on a mountain road or in a city area, and based on the determination result, the electromagnetic valves 31, 20
A control program for selecting a control pattern for the applied currents iA and iB to is stored.

Figures 6c and 7 show the frequency distribution of the numerical value Θ corresponding to the steering angle θ based on actual measurement data described below. When driving on a mountain road, there are many curves, but there are few right-angle turns, so Figure 6c In addition, when driving in a city, there are few curves, but there are many right angle turns at intersections, so the frequency distribution is as shown in Figure 7c. Therefore, the mountain road index J obtained during the execution of the control program has a larger value when driving on a mountain road than when driving in a city area,
By subsequent execution of the control program, the driving state of the vehicle is automatically determined, and one of the control patterns shown in FIG. 5 can be selected from the results.

Next, the control operation of the steering force control device is
This will be explained with reference to the flow chart shown in FIG.

When the car is running, a steering angle signal that changes moment by moment, detected by the steering angle sensor 40 as a numerical value Θ corresponding to the steering angle θ, is detected by the phase determination circuit 4.
5 to a counter (not shown), and a 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 processing operations based on a program at the same time that an interrupt signal is input every predetermined distance traveled. 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 102.
1 is added to the sampling number counter value n, and in the following step 103, the absolute value of the numerical value Θ 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 becomes the same as area M1.
Then, the set value of area M3 is shifted to area M2, etc., and the absolute value of the latest (nth) numerical value Θ is set in the last area M _N , thus updating the memory contents. In this state, the sampling number counter value remains n (=N).

In step 105 following step 103 or 104, the sampling number counter value n is initialized to the read counter H, and in the following step 106, the reading counter H is set to the sampling number counter value n.
The value M _H of the th region is compared with two set values B and C. The set value B is a first threshold value for classifying the small rudder angle range and the medium rudder angle range, and the set value C is the second threshold value for classifying the medium rudder angle range and the large rudder angle range. , in the numerical example described below, B=3, C=12
It is. In step 106, if B≦M _H ≦C, then directly, and if B≦M _H ≦C, in step 107, the frequency counter value D (0
(initialized) is added to 1, and the program proceeds to program 108, where the read counter value H
1 is subtracted from In the following step 109, the read counter value H is compared with the number 0, and H becomes 0.
The above steps 106 to 108 are repeated until H=0, and the program moves to the next step.
Proceed to 110. By repeating steps 106 to 108, the frequency counter value D becomes the frequency of the values Mn of each storage area that satisfy B≦Mn≦C.

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

J=D/n Subsequently, in step 111, the magnitude of the mountain road index J and the reference value E is determined. If J≧E, the numerical value Θ has a frequency distribution as shown in Figure 6 b, and it is determined that the driving is on a mountain road, and if J≧E, the numerical value Θ has a frequency distribution as shown in Figure 7 b. Therefore, it is determined that the vehicle is driving in a city area. If J≧E, the running judgment flag F is set to 1 in step 112.
If J≧E, the running determination flag F is set to 0 in step 113. 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 running in an urban area, and when the number of samples n approaches N, the actual driving state 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 shown in FIG. 8 until the next interrupt signal is input, and starts executing the program according to the flowchart shown in FIG. Outputs an interrupt signal.

In step 200 of FIG. 9, the numerical value V corresponding to the vehicle speed and the numerical value Θ corresponding to the steering angle stored in each of the counters are 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 F
If not = 1, the program will proceed to steps 203 and 204.
Then, apply the current based on the values Θ and V from the characteristic maps A and B for mountain road driving in the ROM53.
iA and iB are searched, and solenoid valves 31 and 2 are searched, respectively.
0 solenoids 33 and 24. In step 202, if F=1, the program proceeds to steps 205 and 206, where the applied currents iA and iB are searched based on the values Θ and V from characteristic maps A and B for city driving in the ROM 53, respectively, and the applied currents iA and iB are searched for, respectively. The voltage is applied to solenoids 33 and 24 of 31 and 20. When step 204 or 206 is completed, 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 6a and 7a are measurement data obtained by actually driving on a mountain road and in a city area, respectively, and outputting an interrupt signal every 10m (sampling number: 130).
The value Θ is 1/18 of the steering angle θ of the handle shaft 18a at the cumulative distance C+D (unit: 10 m).
(Unit: degree). Figures 6c and 7c are the values Θ of Figures 6a and 7a, respectively.
Figures 6b and 7b are frequency distribution histograms of the absolute values of values Θ divided into 5 degree intervals.

As mentioned above, by comparing the respective frequency distribution histograms, the following becomes clear. In other words, when driving on mountain roads, there are many curves, but there are few right angle turns, so
As shown in FIGS. 6b and 6c, 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 c, the frequency of small steering angle ranges is extremely high, and the frequency of medium steering angle ranges rapidly decreases. However, there is a considerable frequency of large steering angle ranges. There is a clear difference in the frequency distribution of the numerical value Θ between mountain road driving and city driving.

Therefore, in Figures 6c and 7c, α is within a relatively narrow range of −B<Θ<B near the center.
and the range γ where Θ<-C and C<Θ near the terminal value
Find the frequency D of the number Θ in the range β excluding
Dividing this by the total frequency number N to obtain the mountain road index J yields the following. Note that B=3 and C=12. Also, for comparison, the standard deviation σ obtained from FIGS. 6a and 7a is also entered.

D J 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. Further, in this case, it is appropriate to set the reference value K for discrimination to 0.3.

The above calculation of the mountain road index J can be similarly performed by using the frequency distribution histogram for the absolute value of the numerical value Θ shown in Figures 6b and 7b, and according to the flowchart shown in Figure 8 above. The program calculates the mountain road index J using the absolute value of this numerical value Θ.

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. In this way, it is possible to avoid a sudden change from the steering force characteristic on a mountain road to the steering force characteristic in an urban area.

In this embodiment, the frequency number D of the numerical value Θ within the range β is divided by the total frequency number n to obtain the mountain road index J, but the reciprocal number may be used as the mountain road index. Also,
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 the drawing]

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 the flow rate control valve device for controlling the discharge amount, FIG. 5 is a graphical representation of the current applied to the solenoid of the electromagnetic valve, and FIGS. In the actual measurement data for the case, a is the actual measurement value, b is the frequency distribution histogram of the absolute value, and c is the frequency distribution histogram. Figures 7 a to c are the actual measurement data for city driving and correspond to Figures 6 a to c. ), FIGS. 8 and 9 are flowcharts showing the control program. Explanation of symbols 1...Steering angle detection means, 2...Storage means, 3...Counting means, 4...Calculating means, 5...
...Determination means, 20... Steering handle.

Claims (1)

[Claims] 1. In a driving state determination device for an automobile equipped with a steering wheel, a steering angle detection means detects a steering angle and generates a steering angle signal, and the steering angle signal is sequentially inputted over time at predetermined time intervals. a steering angle storage means for simultaneously storing a large number of numerical values corresponding to steering angles and updating the stored contents; a first threshold value for classifying a small steering angle range and a medium steering angle range; threshold storage means storing a second threshold for classifying steering angle ranges; and a first threshold stored in the threshold storage means based on the large number of numerical values stored in the steering angle storage means. a counting means for counting the frequency number of numerical values greater than or equal to a threshold value and less than or equal to a second threshold value, and dividing between the frequency number counted by the counting means and the total number of the large number of numerical values stored in the storage means; A calculation means that calculates an index that indicates the driving condition, and this index can be used to calculate whether driving on a mountain road has many curves but rarely turns at right angles, or driving in a city where there are many straight lines and few curves but often turns at right angles. A driving state determination device for an automobile, comprising determining means for determining a driving state.