JPH037667A - Running condition sensing device - Google Patents

Abstract

PURPOSE:To have fine judgement of the variation in the running condition of a car by sensing the running condition associate with the locus of running from the integrated value of the inverted numbers of the rotational radii determined at every unitary distance, and thereby performing each sensing in a short time. CONSTITUTION:From the rotation of the output shaft of a transmission 13 in connection to an engine 4 a car speed sensor 12 senses the car speed, which is fed to a running condition sensor circuit 19 together with a steering angle signal given by a steering angle sensor 14, and there the running condition associate with the locus of running is determined from the steering angles at every unitary distance in the form of the inverted value of the locus radii, and the mean or integral is calculated therefrom, which is output as the running condition index An. A control circuit 11 controls the degree of opening of a variable orifice 10 on the basis of the car speed V, steering angle theta, and this running condition index An, and the reactive pressure of the pressurized fluid fed from a sub-pump 7 is controlled. Thus the running condition can be sensed at every unitary distance in a short time to enable fine judgement of the varying running condition, which serves proper control of the reactive pressure of the power assist mechanism.

Description

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

[Conventional technology]

When controlling a power steering device electronically, the driving state has conventionally been determined based on vehicle speed. And based on this judgment result,
For example, the steering assist force by a hydraulic cylinder or motor is controlled so that the steering force is light in a low speed range and heavy in a high speed range.

However, in power steering systems using conventional technology that determine driving conditions based on vehicle speed, the steering assist force is only responsive to vehicle speed, so it is difficult to drive on mountain roads with many curved roads and on many straight roads. There is a problem in that the control pattern cannot be changed depending on whether the vehicle is driving in a city, and it is not possible to obtain a steering assist force suitable for each driving condition.

In order to solve this problem, there is a system that distinguishes between driving on mountain roads and driving in urban areas based on the frequency distribution of steering angle signals in controlling the steering assist force (Japanese Patent Laid-Open No. 61-220971
Publication No.).

[Problem to be solved by the invention]

However, when the driving state is determined based on the frequency distribution of the steering angle signal, there is a problem in that the driving state can only be determined discontinuously. Therefore, in the conventional device described above, the driving condition is determined by comparing the mountain road index calculated from the frequency distribution of steering angles with a predetermined reference value or a plurality of reference values, and a large number of steering angles are detected. However, the mountain road index could not be obtained until the frequency distribution was calculated, and it took a long time to determine the driving condition, making it impossible to determine the changes in detail.

The present invention has been developed in view of the above circumstances, and the radius of the travel trajectory is determined by the steering angle at each predetermined distance, and the travel index is determined by the integral value or average of the reciprocal of the radius, and the travel state is determined based on the radius. By doing this, the driving state regarding the vehicle's travel trajectory can be detected in a short time each time the steering angle is detected.
It is an object of the present invention to provide a driving state detection device that can finely determine the changes.

[Means to solve the problem]

A driving state detection device according to the present invention includes a vehicle speed sensor that detects vehicle speed and a steering angle sensor that detects a steering angle of a steering mechanism. , means for calculating the traveling distance of the vehicle based on the vehicle speed signal detected by the vehicle speed sensor, and extracting the steering angle detected by the steering angle sensor every predetermined distance of the traveling distance calculated by the means. The vehicle is characterized by comprising means for calculating a value related to the radius of the travel trajectory based on this and the predetermined distance.

[Effect]

In the present invention, the traveling distance is calculated based on the vehicle speed signal from the vehicle speed sensor, the steering angle is detected at each predetermined distance of the calculated traveling distance, and the radius of the vehicle's traveling trajectory is determined by the steering angle at each predetermined distance. Since the reciprocal value is calculated and the average or integral calculation process is used to calculate the driving condition index that indicates the driving condition of the vehicle, information on the radius of the traveling trajectory can be detected every time the vehicle travels a unit distance, and the radius of the traveling trajectory can be detected as a series of the values. The travel trajectory of the vehicle can be determined.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on drawings showing one embodiment thereof.

FIG. 1 is a system diagram of a hydraulic power steering device using a running state detection device according to the present invention. In the figure, 3 is a main pump, and the main pump 3 is constantly rotationally driven by an engine 4 via a pulley 5 during its rotation. In addition, the main pump 3 pressurizes the liquid in the tank 6,
The caloric pressure fluid is supplied to a control valve 2 with a power assist curved structure, which will be described later, and is recirculated into a tank 6. The power assist mechanism includes a rank cylinder 1 that generates a steering assist force, a control valve 2 that switches the feeding direction of pressurized fluid to the rank cylinder 1, and a reaction force chamber 8 that is supplied with pressurized fluid from a sub-pump 7, which will be described later. have. Like the main pump 3, the sub-pump 7 is constantly rotationally driven by the engine 4, pressurizes the fluid in the tank 6, and supplies the pressurized fluid to the reaction force chamber 8.

The reaction force chamber 8 receives the supplied pressurized fluid 1-1 and changes the equivalent spring constant between the input shaft 9 connected to the steering wheel and the output shaft (not shown) on the power assist mechanism side. 8
controls the relative displacement amount of the control valve 2, whose opening degree is determined by the relative displacement amount between the input shaft 9 and the output shaft, by the reaction pressure of the pressurized fluid supplied to the reaction force chamber 8. The reaction pressure of the pressurized fluid from the sub-pump 7 is controlled by a variable orifice 10 connected to the tank 6. The opening degree of the variable orifice 10 is controlled by an opening degree control signal output from a control circuit 11, which will be described later.

The control circuit 11 receives a vehicle speed signal from the vehicle speed sensor 12;
The steering angle signal θ from the steering angle sensor 14 and the running state index A7 from the running state detection circuit 19, which is the gist of the present invention, are given, and the opening control signal is output according to these, and the variable orifice 10 is controlled. The opening degree is controlled and the reaction pressure is controlled.

Vehicle speed sensor 12 electrically detects rotation of an output shaft of transmission 13 connected to engine 4, and provides a vehicle speed signal V to control circuit 11 and running state detection circuit 19. The steering angle sensor 14 is composed of a potentiometer, and the fixed side of the case or the like is provided at a fixed part around the steering wheel, while the sliding side is fixed to the input shaft 9, thereby detecting the steering angle as a voltage signal. This steering angle signal θ is given to the control circuit 11 and the running state detection circuit 19.

FIG. 2 is a block diagram showing a schematic configuration of the running state detection circuit. The vehicle speed signal 'T'iV from the vehicle speed sensor 12 is given to the travel distance detection circuit 19a, where the travel distance is calculated based on time and the vehicle speed signal (2). The mileage detection circuit 19a calculates a unit distance S,9 based on the calculated mileage.
(For example, 40cm) When it is detected that the vehicle has traveled,
The detection signal is output to the calculation section 191). Arithmetic unit 19
b reads the steering angle signal θ at the input timing of the detection signal, and thereby calculates the reciprocal of the radius R of the vehicle's travel trajectory (-]/+
1) is calculated using equation (1). The reason why the reciprocal of the radius is used is to express the straight-ahead state by O instead of by ``O''.

RSo where K: constant The calculation unit 19b reads the steering angle signal θ every unit distance S6, calculates the reciprocal, and outputs it to the integral a I 9 c. When the integrator 19c receives the reciprocal number, it performs an integral operation on the distance as shown in equation (2), obtains a running state index A1 indicating the running state, and outputs it to the control circuit 11.

However, I: Integral constant for distance The driving condition index A7 is an integral value of the reciprocal of the turning radius R, and becomes the driving condition index. If it is large, it can be determined that the vehicle is traveling on a curved road such as a mountain road, and if it is small, it can be determined that the vehicle is traveling in an urban area with relatively few curves.

FIG. 3 is a block diagram showing a schematic configuration of the control circuit, and FIG. 4 is a graph showing an example of a control pattern of the control circuit.
The vertical axis shows the reaction pressure, and the horizontal axis shows the vehicle speed. The range of steering angle control is indicated by hatching, and when the steering angle is large, the anti-horn pressure is increased.

The control circuit 11 receives a vehicle speed signal ■, a steering angle signal θ, and a running condition index A. are given, and based on these relationships, the orifice opening degree is determined and the reaction pressure is controlled. The reaction pressure decreases as the orifice opening degree increases, and the three-dimensional relationship between each input signal and the opening control signal based on the relationship between the reaction pressure and the vehicle speed, driving condition, and steering angle shown in Fig. 4 is shown in Fig. 4. The original relationship is written as 1.0 in the memory element 15a. Reading of the opening degree control signal from the storage element 15a is performed by an access circuit section 15b that accesses according to each input signal. The opening control signal is given to the drive circuit 18, and the drive circuit 18 supplies current to the actuator 10a of the variable orifice 10 by an amount proportional to the magnitude of the opening control signal, thereby activating it. This opening degree control signal corresponds to the number of steps when the actuator 10a is a steering motor, or to the value of current flowing through a coil when the actuator 10a is a solenoid.

The relationship between the reaction force pressure, vehicle speed, steering angle, and running condition is shown in Figure 4. When the vehicle is traveling straight (A,,!-;O), the reaction pressure is reduced to eliminate the feeling of wobbling of the steering wheel. The increase rate is increased and changed according to the vehicle speed. Further, in this steering angle control using the steering angle, the reaction pressure increases as the steering angle increases, giving a feeling of cutting when the steering wheel is rotated.

Furthermore, the width of the steering angle control indicated by hatching becomes smaller as the turning radius becomes smaller (A, , → larger). This reduces changes in steering characteristics on curved roads such as mountain roads and provides a stable steering feel.

Next, the operation of the apparatus of the present invention constructed as shown below will be explained. FIG. 5 is a flowchart of the running state detection operation.
FIG. 6 is a flowchart of orifice opening degree control using this method.

First, the vehicle speed signal V is read at a predetermined timing (S1
0), the traveling distance is detected by the vehicle speed signal ■. Then, the unit distance S, whether or not the distance traveled is determined by the distance detection circuit 19a.
If the vehicle is not running, return is made; if the vehicle is running, the steering angle signal θ is read (S12).
), the calculation unit 19b calculates the reciprocal of the rotation radius R (S
13). The calculated reciprocal is given to the integrator 19c, where it is integrated to obtain the running condition index Aゎ using the above-mentioned (warm formula) (514).

On the other hand, in orifice opening control, first the vehicle speed signal ■ is read (S20), and then the steering angle signal θ is read (S21).

Then, in the running state detection routine from step 10 onwards, several people determine the running state. is calculated (522) and read by the microcomputer 15 (S23). The access circuit section 15b accesses the IJ element 15t] based on the read vehicle speed signal (■), steering angle signal (0), and driving condition index (524), reads out the control signal, and outputs it (S25).
. This is performed every time the unit distance S is taken in (S26).

In this way, in this embodiment, each time the steering angle is detected, the driving condition index A is outputted, and an opening control signal that is three-dimensionally stored in advance based on the vehicle speed, steering angle, and driving condition index is outputted. Therefore, orifice opening degree control can quickly respond to changes in driving conditions.

In this embodiment, the integral value of the reciprocal of the turning radius is used as the driving condition index in order to suppress the variation in detected values, but the present invention is not limited to this (9), and the turning radius is used as the driving condition index. It goes without saying that the reciprocal value may be used as it is or its average value may be used.

Further, in this embodiment, the device of the present invention is used in a hydraulic power steering device, but it goes without saying that the present invention is not limited to a hydraulic power steering device, but can also be applied to an electric power steering device or other types of power steering devices.

[Effect] As explained above, according to the present invention, the running state related to the running trajectory is detected by the integral value of the reciprocal of the turning radius obtained for each unit distance, so the running state can be detected for a short time every unit distance. This has the advantage of being able to detect changes in detail and making detailed judgments.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a hydraulic power steering device using a running state detection device according to the present invention, Fig. 2 is a block diagram showing a schematic configuration of a running state detection circuit, and Fig. 3 is a schematic diagram of a control circuit. Figure 4 is a block diagram showing the configuration, Figure 4 is a graph showing an example of the control pattern of the control circuit, Figure 5 is a flowchart of the running state detection operation, and Figure 6 is a flowchart of orifice opening control using the same. It is 1. 12...Vehicle speed sensor] 9...Driving state detection circuit 1911...Arithmetic unit 4 19,] 9c...Steering angle sensor - Traveling distance detection circuit integrator] 2 Patent Applicant: Koyo Seiko Co., Ltd.

Claims (1)

[Scope of Claims] 1. A driving state detection device that detects a driving state related to a traveling trajectory of a vehicle, which includes a vehicle speed sensor that detects vehicle speed, and a steering angle sensor that detects a steering angle of a steering mechanism. a means for calculating a travel distance of the vehicle based on a vehicle speed signal detected by the vehicle speed sensor; and extracting a steering angle detected by the steering angle sensor for each predetermined distance of the travel distance calculated by the means; A driving state detection device comprising means for calculating a value related to the radius of the traveling trajectory based on this and the predetermined distance.