JPS63291774A - Running state detecting device for automobile - Google Patents

Abstract

PURPOSE:To enable the detection of a change in road condition by making many storage areas store in turn the values corresponding to respective steering torque at a preset interval so that the ratio of these many storage areas can be completed and, thereby the road condition (whether the automobile is running on a city-street road or on a mountain road) can be detected from the result of this ratio. CONSTITUTION:A torque sensor 25 is provided, which is used to detect the hand steering torque that is input from a steering handle 16 into a handle shaft 15. The values corresponding to the hand steering torque, which is detected by this torque sensor 25, is stored in many storage areas possessed by a storage means 2 at a preset interval by means of an update means 1, thereby updating the stored values. These stored contents of this storage means 2 are output to an operating means 3, and the ratio of the storage area excluding the storage areas, in which the numerical values corresponding to the hand steering torque within the predetermined range in the vicinity of range-0 of the whole storage areas are stored, is computed. Taking this ratio computed as the running state index, the driver can tell the running state, or whether the road on which his automobile is running is a city-street road or a mountain road, from the size of these numerical values.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a driving state detection device for an automobile, which is used to control steering characteristics and tonnage height according to the driving state.

(Prior art) Conventionally, the driving state of a vehicle has usually been detected based on the vehicle speed, and based on this detection result, for example, in a power steering system, the ratio of assist force to manual steering torque input from the steering wheel is determined. There are controls that make it larger in low speed ranges and smaller in high speed ranges. Furthermore, as shown in Japanese Patent Application Laid-open No. 61-220971, there is a system that detects the driving condition of a car based on the steering angle. According to this, it is possible to accurately detect driving conditions such as whether it is on a mountain road or in a city area. , it is possible to more appropriately control the steering characteristics and vehicle height according to the actual driving conditions.

(Problems to be Solved by the Invention) However, the technology disclosed in JP-A No. 61-220971 requires a steering angle sensor to detect the steering angle. The problem is that it cannot be immediately applied to power steering systems that are equipped with a torque sensor to detect manual steering torque for assist force control, such as type power steering systems, but do not have a steering angle sensor. there were. The present invention attempts to solve the above problem by accurately detecting driving conditions such as whether a mountain road is a city road or a city road using a torque sensor that detects manual steering torque.

(Means for Solving the Problems) For this purpose, as shown in FIG. 1, the vehicle running state detection device according to the present invention uses a torque sensor 25 that detects manual steering torque input from the steering wheel to the steering wheel shaft. and storage means 2 having a large number of storage areas, and sequentially storing numerical values corresponding to the manual steering torque detected by the torque sensor 25 in the plurality of 11 areas at predetermined intervals, and storing the stored values. Update means 1 for updating;
The apparatus is equipped with a calculation means 3 for calculating the ratio of the storage area or its complement, excluding the storage area in which numerical values corresponding to the manual steering silk within a predetermined range around θ are stored.

(Function) The updating means 1 stores the manual steering torque detected by the torque sensor 25 as it is or converts it according to a predetermined procedure at predetermined intervals and sequentially stores it in a large number of storage S areas of the storage means 2 for updating. . The operator stage 3 calculates the number of storage areas of the storage means 2 excluding the storage area in which a numerical value m corresponding to the manual steering torque within a predetermined range near O is recorded, and calculates the number of storage areas. Calculates the ratio to the total number of storage areas or its complement.

As shown in the actual measurement example in Figure 5, the frequency distribution of manual steering torque is such that when driving on a mountain road (see Figure 5 (a)), the frequency distribution is within a predetermined range around 0, while the other frequency numbers are There are quite a few. On the other hand, in the case of city driving (see FIG. 5(b)), the number of frequencies within a predetermined range near O is extremely high, and the number of frequencies other than that is extremely small. Therefore, in the ratio calculated by the calculation means 3, the value when driving on a mountain road is larger than the value when driving in a city area, and the complement of this ratio is the opposite.

(Effects of the Invention) As described above, according to the present invention, the ratio or its complement calculated by the calculation means from the manual steering torque detected by the torque sensor has the same value when driving on a mountain road and when driving in a city area. Because of this difference, even if a vehicle is not equipped with a steering angle sensor, as long as it is equipped with a torque sensor, it is possible to accurately detect driving conditions such as whether it is on a mountain road or in a city.

(Example) The present invention will be explained below using an example shown in FIGS. 2 to 8. As shown in FIG. 2, a gear box 10 of the steering device supports a binion 11 and a rack par 12 that mesh with each other, the binion 11 is connected to a steering handle 16 via a handle shaft 15, and the rack par 12 is connected to a steering link. It is connected to the front wheel 17 via a mechanism. The steering wheel shaft 15 is provided with a torque sensor 25 that detects manual steering torque input from the steering wheel 16, and a DC torque motor 26 that generates an assist force under the control of an assist force calculation circuit 20, which will be described later. The manual steering torque inputted to the pinion 11. The front wheel 17 is directed through the rack par 12.

As shown in FIG. 2, the assist force calculation circuit 20 mainly includes a microprocessor (hereinafter simply referred to as CPU) 21, a read-only memory (hereinafter simply referred to as ROM) 22, and a writable memory (hereinafter simply referred to as RAM) 23. This is an r& element. The torque sensor 25 and a vehicle speed sensor 27 that detects the vehicle speed of the automobile are connected to the CPU 21 through a flash interface, and a motor drive circuit 28 that controls and drives the torque motor 26 is connected through a flash interface. has been done. The motor drive circuit 28 is a chopper circuit, which inputs power at a predetermined drive voltage from an alternator 34 driven by an engine 30 of the automobile, and modulates the voltage applied to the torque motor 26 according to a control signal from the CPU 21. Torque motor 2
This is to control the output torque of No. 6. The field coil of this alternator 34 is connected to a battery 33 to be supplied with current, and the battery 33 is connected to a charging alternator 31 driven by an ennon 30 and whose output voltage is adjusted by a voltage regulator 32 to be charged. .

A control pattern for the current applied to the torque motor 26 is stored in the ROM 22 as a characteristic map. Figure 3A
, B are graphical representations of this characteristic pattern. FIG. 3A shows the change characteristics of the current tA applied to the torque motor 26 with changes in the manual steering torque and the vehicle speed V when the driving condition index J is O (city driving), which will be described later, and the applied current Z^ is As shown in the figure, it increases as the manual steering torque increases, but does not change in the low torque and high torque ranges, and is set to decrease as the vehicle speed V increases. In addition, ts3 diagram B shows a similar change characteristic of the applied current when the driving condition index J, which will be described later, is 99 (driving on a mountain road with many bends), and the applied current Z@ changes with the same tendency as t^. , its value is generally set to be smaller than t^.

The RAM 23 has a large number (8) of storage areas (buffers D0 to
DN-1).

In this embodiment, the storage capacity of each buffer 7D, ~DN-1 is all 1 bit, and they are functionally arranged in a ring, and the CPU 21 stores a predetermined travel distance #l (for example, 5 meters), the numerical value 1 (0, 2 - J-11≦ITMI≦0.51) is determined depending on the level of manual steering torque detected by the torque sensor 25.
(in the case of g-11+) or the value O (in cases other than the above)
Let me remember this record 1! Operation is buffer D0 to DN-1
Each time it cycles through, it returns to the beginning and repeats the operation to update the memory contents.

The manual steering torque input from the steering wheel 16 to the steering wheel transfer 15 is, for example, as shown in Fig. 4 (
The frequency distribution of the manual steering torque TM (absolute value) that fluctuates as shown in the left half of a) and is detected every predetermined traveling distance is the fifth
As shown in the actual measurement example in Figure 4(b), the proportion exceeding 0.21 (g-m) is extremely small.Also, the manual steering torque when driving on a mountain road is, for example, in the right half of Figure 4(a). As shown in the actual measurement example in Fig. 5(a), the frequency distribution increases as shown in the actual measurement example in Fig. 5(a).Therefore, as mentioned above, the numerical value 1 or 0 is stored. Using the buffer 00 to 0N-1, calculate the following formula: % Formula % (1) K: constant (determined experimentally to be 99 J in the case of vigorous driving on extremely winding mountain roads) If the ratio J is calculated and the value J is taken as a running condition index, this running condition index J will change to the solid line in FIG. 4(b) in response to the fluctuation of the manual steering torque in FIG. 4(a). It varies as shown, and becomes small when driving in a city area and becomes large when driving on a mountain road.Therefore, it is possible to detect whether the driving condition is in a city area or a mountain road.

This driving condition index J frequently increases or decreases depending on the driving condition as shown in FIG. It may give an unnatural feeling. Therefore, in this embodiment, as shown by the broken line in FIG. A corrected operating state index Ja is calculated so as to decrease, and the torque motor 2 is adjusted based on this Ja.
The current applied to 6 is calculated. In this way, when the driving condition index increases, which increases the tension of the driver, the corrected driving condition index Ja immediately increases to respond to this, but when the driving condition index decreases, which causes the driver to become less nervous, the corrected driving condition index Ja decreases gradually, and the assist force increases. This is preferable because it can prevent frequent changes. However, the present invention is not limited to such embodiments.

Driving status finger! In a conventional electric power steering system that does not perform control using &J (or Ja), the current 1o applied to the torque motor 26 calculated by the CPU 21 is
As shown by the broken line in Figure (e), the assist force is proportional to the manual steering torque (when the 11! speed is constant), and therefore the ratio of the assist force to the manual steering torque is approximately constant.

In contrast, the current I applied to the torque motor 26 in this embodiment is reduced from the conventional applied current 1o according to the value of the corrected driving state index Ja, as shown by the solid line in FIG. 4(c). Therefore, the ratio of the assist force to the manual steering torque also decreases depending on the corrected driving condition index Ja. In other words, when driving in the city, where the same finger fl J a is small, the ratio of assist force decreases less, so the steering wheel becomes lighter than before, and when driving on mountain roads, where the same finger fl J a is large, the steering wheel becomes lighter. The handle is also heavier than before.

FIG. 6 shows a 70-chart of the control program used when the CPU 21 calculates the operating state index J.
The figure shows a 70-chart of the control program used when calculating the corrected operating condition index Ja from the operating condition indicator IJ, and FIG. - Shows a chart.

Each of these control programs is stored in the ROM 22.

Next, the operation of this embodiment will be explained with reference to the flow chart.

When the main switch of the car is turned on, the assist force calculation circuit 20 calculates each variable (including the corrected driving state indicator r!LJ a).
is set to 0 or a predetermined initial value. Manual steering torque and vehicle speed V that change from moment to moment in the driving state of the automobile
are detected by the torque sensor 25 and the vehicle speed sensor 27, and their current values are stored in flash registers.

(2) Calculation process of luck status indicator IJ This calculation process is repeatedly executed based on the chart 70 in FIG. 6 each time an interrupt signal is output every time the car travels 5 meters. First, in step 100, the CPU 21 reads the manual steering torque stored in the register, and in the subsequent step 101, adds 1 to the sampling counter value n, and then in step 102.
Buffer the sampling counter value n at r D6
- Compare with the total number N of Dw-+. If n≧N, the sampling counter value n is reset to 0 in step 103, and if n≧N, the process continues as it is in step 1.
Proceeding to 04, CPU21 sets 0.2 to 9-m≦ITMI
≦0.5? − Determine whether or not the 0.2, -ITP≦ITP, and +1≦0.5 if 71, the stored value of the n-th buffer 111n is set to 1 in step 105.
If not, the value stored in the buffer Dn is set to O in step 106, and the process proceeds to step 107.
The CPU 21 calculates the running condition index J using the above equation (1), and ends the execution of the control program according to the chart 70 in FIG.

■) Calculation process of the corrected driving condition index Ja This calculation process is repeatedly executed based on the 70-chart in Fig. 7 every time the own IJl vehicle travels 20 mF and an interrupt signal is output. . First step 110
In step 111, the CPU 21 compares the driving condition index J calculated in step 107 with the corrected driving condition index Ja calculated in the previous execution, and if J>Ja, sets Ja=J in step 111, and if J>Ja Otherwise, in step 112, Ja''Ja is set to 1 and the execution of the control program according to the chart 70 in FIG. 7 is terminated.

(2) Calculation and output processing of applied current I This calculation process is constantly executed using the calculation result of the corrected operating state index Ja in (2) above. First, in step 120, the CPU 21 reads the ROM 2 based on the current vehicle speed V read in the flash step and the manual steering torque l read in step 100.
2, the applied current 11 is determined from the characteristic map A in FIG.
In the following step 121, the applied current t2 is similarly searched from the characteristic map B. These two applied currents 7H4'2 and the corrected operating condition index Ja calculated in the step 111 or 112 are calculated in the following step 1.
In step 22, the applied current is calculated by substituting it into the following formula % formula %, followed by step 12
3, the CPU 21 supplies the current I to the torque motor 2 via the flash interface and the motor drive circuit 28.
6 is applied, and the execution of the control program according to chart 70 in FIG. 8 is completed.

The CPU 21 executes each of the above 70- for each of the predetermined running distances.
The control program based on the chart is repeatedly executed, and the torque motor 2 is adjusted according to the corrected running condition index Ja and the vehicle speed V.
Outputs the applied current to 6. As a result, when driving in the city, the applied current ■ is increased to increase the ratio of assist force to manual steering torque, so the steering wheel becomes lighter even when going uphill, and when driving on mountain roads, the applied current I is reduced. Therefore, the handle is heavier than before even when going uphill.

Note that the complement of the ratio J calculated by equation (1) (W) is
= 1-J) also has the opposite tendency, but it changes depending on the driving condition, whether it is an urban area or a mountain road, so if this complement is used as the driving condition index, the driving condition can be detected in the same way as in the above embodiment. . Furthermore, in the above embodiment, the value of the buffer Dn in <0.2Ks-m≧ITMI≧0.5(:g-m is set to 1 as described above, but 0.2Ks-
The above-mentioned processes may be performed by setting all the values of the buff 7yDn to 1 when m≧ITMI.

Further, in the above embodiment, the manual steering torque detected by the torque sensor 25 is set to 0 or 1 depending on the value.
After conversion, the data is stored in each of the buffers D0 to DN, 1. This has the advantage that the storage capacity of each buffer is only 1 bit, so the storage capacity of the entire storage means is sufficient.

However, the present invention is not limited to such embodiments.

Further, the present invention may be implemented by having each of the control programs executed at predetermined time intervals instead of every predetermined travel distance. Characteristic map A.

Instead of B, an arithmetic expression may be stored in the ROM 22, and the applied current 1Av1 day may be calculated from the manual steering torque, the running condition index J (or Ja), and the vehicle speed V.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a vehicle running state detection device according to the present invention, PIS Fig. 2 to Fig. 8 shows an embodiment of the present invention in a power steering device, Fig. tpJ2 is an overall explanatory diagram, and Fig. PttJ3 is a characteristic diagram of changes in manual steering torque and current applied to the torque motor with respect to vehicle speed, Figure #S4 is a diagram showing changes in manual steering torque, each driving condition index, and applied current, and Figure 5 is a frequency distribution of manual steering torque. A diagram showing
6 to #S8 are 70-charts of the control program. Explanation of symbols 1...Updating means, 2...Storage means, 3...Calculating means, 25...Torque sensor.

Claims (1)

[Claims] a torque sensor for detecting manual steering torque input from a steering wheel to a steering wheel shaft; a storage means having a large number of storage areas; and a numerical value corresponding to the manual steering torque detected by the torque sensor at predetermined intervals. an updating means for sequentially storing data in the plurality of storage areas and updating the stored values thereof; A driving state detection device for a vehicle, comprising calculation means for calculating a ratio or its complement.