JPH0240544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION The present invention comprises a driving state detecting means that includes the traveling speed of a vehicle, and a power controlling means that controls the power of a steering device according to the detected traveling state, and at least The present invention relates to a power steering device for a vehicle that adjusts the degree of reduction in steering force according to the traveling speed of the vehicle.

Recently, in automobiles, a shift pattern that determines the shift position is prepared in advance, and the shift pattern is compared with the vehicle speed to determine the shift position, for example, from 1st to 4th gear.
A system has been developed that employs an automatic shift control system that automatically selects the shift position based on the speed.

As this type of automobile, one further equipped with a power steering device is provided. Conventional power steering devices include, for example, the power steering device described in JP-A-56-34566 and the device described in JP-A-55-55059 (pump device for power steering device). The former power steering device increases the degree of reduction in steering force as the shift position changes from a low gear to a high gear, thereby performing control to lighten the steering wheel. The latter type of power steering device controls the steering force to be reduced to a greater extent and the steering wheel to be lighter if the torsion angle of the steering shaft is large.

Although the present invention is not limited to automobiles that employ the automatic transmission control system as described above, in automobiles equipped with a power steering device, the conventional power steering device does not change the shift position from a low gear to a high gear. The power steering system is designed to increase the degree of reduction of the steering force as the angle of rotation increases, or the degree of reduction of the steering force increases as the torsion angle of the steering shaft increases. Focusing on the fact that it is difficult to perform control for optimal matching, the purpose of this invention is to control the power steering system to better match the actual driving conditions.

Structure of the Invention The structure of the present invention that achieves the above object will be explained below.

As illustrated in FIG. 3, the power steering device for a vehicle according to the present invention includes a running state detection means M1 that includes the running speed of the vehicle.
and steering device M2 according to the detected running state.
and a power control means M3 for controlling the power of the vehicle, and adjusts the degree of reduction of steering force according to at least the traveling speed of the vehicle, wherein the traveling state of the vehicle is a straight-ahead state or Further, the power control means M3 controls the power of the steering device M2 when it is determined that the vehicle is in a turning state under the same speed condition. The present invention is characterized in that it includes a power correction means M5 that makes the power of the steering device M2 smaller than the power of the steering device M2 when it is determined that the vehicle is traveling straight.

In the power steering device for a vehicle of the present invention having the above configuration, the power of the steering device is controlled according to at least the traveling speed of the vehicle, and the degree of reduction of the steering force is adjusted. In a turning state, control is performed to correct the power of the steering device to a value smaller than the power of the steering device when the vehicle is in a straight-ahead state under the same speed conditions, thereby reducing the degree of reduction of the operating force.

[Embodiments] In order to further clarify the structure and operation of the present invention described above, preferred embodiments of the vehicle power steering device of the present invention will be described below.

FIG. 1 shows a block diagram representing an embodiment of the present invention applied to an automobile that performs automatic transmission control.

In FIG. 1, 1 is a control device, 2 is a running state detection means, 3 is a power steering device, 4 is a microcomputer which is an example of arithmetic control means according to the present invention, and 5 is a vehicle speed sensor, for example, a transformer (not shown). A steering angle sensor 6 is disposed on the transmission output shaft and generates a pulse signal with a frequency proportional to the vehicle speed, and is composed of a potentiometer that detects the steering angle of the front wheels and outputs a corresponding steering angle signal. 7 is a shift position sensor that generates a shift position signal corresponding to a shift position (for example, 1st gear to 4th gear), which is composed of two solenoids driven by an automatic transmission control device (not shown), for example. , 8 is a linear solenoid that controls the bypass amount of pressure oil supplied to the power cylinder (not shown) of the power steering device 3 according to the applied current, and 9 is a linear solenoid that shapes the waveform of the pulse signal from the vehicle speed sensor 5 and uses a micro An input buffer outputs to the interrupt input port of the computer 4; 10 is an input buffer that amplifies the steering angle signal from the steering angle sensor 6 and outputs it to the input port of the microcomputer 4; 11 is a shift position signal from the shift position sensor 7. An input buffer 12 detects and outputs a control signal from the microcomputer 4 to the input port of the microcomputer 4.
A duty signal generating section 13 amplifies the duty signal from the duty signal generating section 12 and outputs the amplified current to the linear solenoid 8. The driving section 14 represents a buffer that detects a change in the current flowing through the linear solenoid 8 based on a voltage fluctuation of a battery (not shown) and performs constant current feedback control on the duty signal generating section 12.

When an engine key switch (not shown) is turned on, the microcomputer 4 starts arithmetic processing as shown in the flowchart of FIG.

In FIG. 2, 101 is RAM in the microcomputer 4;
This represents the step of initializing the CPU, timer, I/O circuit, etc.

Reference numeral 102 represents a step of calculating and storing the vehicle speed V using the clock number calculated by executing a vehicle speed interrupt routine (not shown) as a parameter.

Reference numeral 103 represents a step of calculating and storing the shift position s based on the shift position input signal from the input buffer 11.

Reference numeral 104 represents a step of calculating and storing the steering angle φ, that is, the steering angle φ, based on the steering angle input signal from the input buffer 10.

105 is based on the vehicle speed V calculated in step 102 and the constant k(s) corresponding to the shift position s calculated in step 103, using the following formula: V1=V+k(s)・V... (1) represents the step of calculating the pseudo vehicle speed V1.
In the above equation (1), the constant k(s) is preset so that it takes a larger value as the shift position becomes a higher gear. Therefore, even if the actual vehicle speed V is the same, a larger value is obtained as the pseudo vehicle speed V1 when the shift position s is on the high speed side than when the shift position s is on the low speed side.

106 is the pseudo vehicle speed V1 calculated in step 105 above and the preset upper limit value Vmax of the vehicle speed V.
and a preset reference value of the vehicle speed V, that is, the reference vehicle speed.
Based on Vref (e.g. 100Km/h) and the reference angle φref corresponding to the reference vehicle speed Vref, the following formula: φ0=Vmax−V1/Vmax−Vrer・φref……(2) corresponds to the pseudo vehicle speed V1. This represents the step of calculating and storing the first turning angle φ0 (stable area near the center of the steering wheel). The stability area near the center of the steering wheel means that if the steering angle is within this stability area, the steering angle is within the so-called steering play range, or there is a deviation caused by the road surface condition. This is an area in which it is determined that the driver's intention is to drive straight. Within this region, the stability of the straight-ahead vehicle is maintained extremely well.

Note that by executing the first turning angle φ0 calculation process in step 106 and the pseudo vehicle speed V1 calculation process in step 105, which calculates the pseudo vehicle speed V1 used for calculating the first turning angle φ0, the patent claim can be achieved. A function corresponding to the boundary angle calculation means described in the second range is realized. For example, when the pseudo vehicle speed V1 calculation process (step 105) and the first turning angle φ0 calculation process (step 106) are executed, step equations (1) and (2) are executed.
As is clear from the above, the first angle φ0 (boundary angle) is calculated to be a smaller value as the vehicle speed is higher. In addition, steps 103 and 1, which include step 103,
By executing the processes of Nos. 05 and 106, a function corresponding to the boundary angle calculation means including the boundary angle correction means described in claim 3 is realized. That is, as is clear from equation (1), if the shift position s obtained by the calculation process in step 103 is on the high speed side, the pseudo vehicle speed V1 is calculated to be a larger value than when the shift position s is on the low speed side. (corresponding to boundary angle correction means). As a result, step 106
In the calculation process, the first angle φ0 (boundary angle) is calculated as a smaller value as the shift position moves from the low speed side to the high speed side.

107 represents a step for determining whether or not the steering angle φ calculated in step 104 is less than or equal to the first turning angle φ0.

Note that by executing the process of determining whether the steering angle φ is less than or equal to the first turning angle φ0 in step 107, a function corresponding to the angle comparing means described in claim 2 is realized. . Steering angle φ
If the steering angle φ is less than or equal to the first steering angle φ0, the vehicle is determined to be traveling straight, and if the steering angle φ exceeds the first steering angle φ0, the vehicle is determined to be turning. Of the processes described above, the steering angle φ calculation process (step 104) and the first steering angle φ0
Arithmetic processing (step 106) and steering angle φ
By executing the process (step 107) of determining whether the cutting angle is less than or equal to φ0, the function corresponding to the progress state determining means recited in claim 1 is realized as an example. , it is determined whether the vehicle is traveling straight or turning.

108, when it is determined that the steering angle φ is less than or equal to the first steering angle φ0 (step 107) and that the vehicle is traveling straight, the above-mentioned pseudo vehicle speed V1 corresponding to the linear solenoid current is set as the current vehicle speed Vi. represents the step to be taken.

In step 109, when it is determined that the steering angle φ exceeds the first steering angle φ0 (step 107) and the vehicle is in a turning state, the current vehicle speed Vi is calculated by the following formula: Vi=V1+c(φ−φ0 ) V1 ... represents the step of calculating and storing according to (3). Note that in the above formula (3), c is a constant.

Incidentally, by executing the current vehicle speed Vi calculation process in step 109, a function corresponding to the power correction means described in claim 1 is realized. Current vehicle speed Vi when steering angle φ exceeds first turning angle φ0
is the current vehicle speed Vi=V1 (step 108) when the steering angle φ does not exceed the first steering angle φ0, and the additional value obtained by multiplying the constant c by the value when the steering angle φ exceeds the first steering angle φ0. The added large value is calculated (step 109). When the current vehicle speed Vi is calculated as a large value in this way, the linear solenoid output current 10 is calculated as a large value in the next step 110, and as will be described later, the amount of bypass supplied to the power cylinder is increased, and the amount of bypass supplied to the power cylinder is increased. The amount of pressurized oil supplied to the engine decreases, and the power of the steering force decreases.

Reference numeral 110 indicates the current vehicle speed Vi calculated in step 108 or step 109, the preset upper limit value Vmax of the vehicle speed V, the linear solenoid valve driving minimum current Imin, the linear solenoid maximum energizing current Imax, and the linear solenoid valve. Based on the vehicle speed Vmin corresponding to the minimum drive current Imin, the following formula: 10=Imin+(Imax−Imin)・Vi−Vmin/Vmax−Vmin
...(4) represents the step of calculating the linear solenoid output current 10.

Reference numeral 111 represents a step for outputting a control signal corresponding to the linear solenoid output current 10 from the output port to the duty signal generator 12.

The duty signal generating section 12 outputs a corresponding duty signal to the driving section 13 based on the control signal from the microcomputer 4, and the linear solenoid 8 is driven by the linear solenoid output current I via the driving section 13. When the voltage of the battery (not shown) fluctuates, the amount of the change is detected by the buffer 14 and fed back to the duty signal generating section 12, and the linear solenoid output current I changes in accordance with the voltage fluctuation. The valve is optimally controlled.

As described above, in the vehicle power steering system having the configuration of this embodiment, as shown in the calculation formula (4) in step 110, basically, the calculation that increases the linear solenoid output current 10 as the vehicle speed is high is performed. do the
Control that increases the bypass amount of pressure oil to reduce the amount of pressure oil supplied to the power cylinder of the steering gear, and the higher the vehicle speed, the smaller the power of the steering gear, which means that a stronger steering force is required. do.

In this control, in the embodiment device, when calculating the linear solenoid output current 10, a value of current vehicle speed Vi is introduced as the vehicle speed, and to this current vehicle speed Vi,
The values of the vehicle speed from the vehicle speed sensor, the steering angle from the steering angle sensor, and the shift position from the shift position sensor are reflected to calculate the value of the linear solenoid 10 to control the power of the steering device.

That is, when it is determined in step 107 that the steering angle φ is less than or equal to the first turning angle φ0 calculated in the previous step 106, in step 108,
While the pseudo vehicle speed V1 is directly set as the current vehicle speed Vi, when it is determined that the steering angle φ of the steering wheel is larger than the first steering angle φ0 calculated previously, in step 109, the current vehicle speed is Vi is set to a value obtained by adding to the value of the pseudo vehicle speed V1 an additional value obtained by multiplying the value at which the steering angle φ exceeds the first turning angle φ0 by a constant c.

Therefore, when the steering angle φ of the steering wheel takes a value larger than the first steering angle φ0 indicating a stable region, the value of the linear solenoid output current 10 is set to a value where the steering angle is less than the first steering angle φ0 under the same conditions. The value becomes larger than when the steering gear is set, and the power of the steering device is reduced, and control is performed that requires a strong steering force. Moreover, at this time, as the turning progresses and the steering angle φ becomes larger than the value of the first steering angle φ0, control is performed to increase the value of the current vehicle speed Vi and gradually increase the force required as the steering force. Let's do it.

In other words, in the control described above, the higher the vehicle speed, the smaller the power of the steering device is, and the stronger the steering force is required. If it is determined that the vehicle has moved from a straight-ahead state to a turning state outside the range of the first turning angle φ0, which indicates , control is performed to further reduce the power of the steering device and to require even stronger steering force.

In addition, in the vehicle power control device of the embodiment, in the calculation process (step 106) of the first angle of inclination φ0 related to the above control, the first inclination angle φ0 is basically calculated as a small value when the vehicle speed is high. ing. Therefore, the higher the vehicle speed, the narrower the range of steering angles that are determined to be in the straight-ahead state, and in the above-mentioned control, the higher the speed, the smaller the steering angle is used to determine that the vehicle is in a turning state. The first turning angle φ0 is determined according to the actual driving conditions determined according to the conditions, i.e., it is necessary to turn with a small steering angle if the vehicle speed is not high, and the above-mentioned control is performed to adjust the steering force. The amount of force required is determined as follows.

Furthermore, in the device of this embodiment, the first cutting angle φ0
When calculating, as shown in equation (2) in step 106, a value called pseudo vehicle speed V1 that takes the shift position into account is introduced as the vehicle speed, and even if the speed conditions are the same, the shift position is shifted to the high speed side. Accordingly, the pseudo vehicle speed
An operation is performed in which the value of the first angle φ0 is decreased by increasing the value of V1.

As a result, even if the actual speed is the same and the steering angle is the same, as the shift position moves to the high speed side, the value of the linear solenoid output current 10 increases, reducing the power of the steering device. control to gradually increase the need for steering force.

As explained above, according to the vehicle power steering system of the embodiment, when the vehicle shifts to a turning state, control is performed such that as the turning progresses, a stronger force is required as the steering force. This has the excellent effect of being able to stabilize the steering operation and prevent sudden steering operations, since excessive steering is less likely to occur during steering operations. Such control of the steering force reduction degree not only allows the driver to intuitively recognize a safe steering operation amount, but also maintains good running stability of the vehicle.

Furthermore, even if the degree of reduction in steering force is controlled depending on the state of travel of the vehicle, when the state of progress becomes a straight-ahead state, the degree of reduction will be the same under the same speed conditions; for example, if the road surface condition is bad Even if the steering wheel is removed, if the strength of the steering force does not change as long as the vehicle is moving straight, there will be no discomfort, and the advantage is that it is extremely easy to use.

Furthermore, according to the device of the embodiment, control is performed to change the first turning angle φ0, which determines the traveling state of the vehicle, according to the vehicle speed, so that the above-mentioned effect of stabilizing the steering operation can be further improved. This has the effect of being able to be realized safely in accordance with actual driving conditions.

Further, according to the device of this embodiment, even if the speed is the same, if the shift position is on the high speed side, the driver is in a relatively stable driving condition such as high speed driving, and the frequency of operation by the driver is reduced. Therefore, a strong steering force is required, but if the shift position is on the low speed side, the frequency of steering operations will be reduced, such as when turning at an intersection in a city or pulling into a parking lot. Since the amount of operation is increasing, control is realized in which a relatively weak steering force is required, and operability can be improved, resulting in extremely good usability.

In the embodiment described above, one first turning angle φ0 is set and the current vehicle speed Vi is divided into two stages based on the comparative effect of the first turning angle φ0 and the steering angle φ. The invention is not limited to this,
It is possible to set a plurality of first angles φ0 and classify the current vehicle speed Vi into multiple stages based on the comparison results for each set value. In this case, control should be performed more suited to the actual vehicle running condition. Can be done.

Effects of the Invention As described in detail above, according to the power steering device for a vehicle of the present invention, the degree of reduction of steering force is adjusted at least according to the traveling speed of the vehicle, but when the vehicle shifts to a turning state, it changes to a straight-ahead state. Since the steering force reduction degree is controlled so that the power is lower than the value of the power of the steering device when turning, and a large force is required as the steering force, an excessive amount of steering operation occurs when turning. This has the excellent effect of stabilizing the steering operation and preventing sudden steering operations. Such control of the steering force reduction degree not only allows the driver to intuitively recognize a safe steering operation amount, but also has the effect of maintaining good running stability of the vehicle.

Moreover, according to the power steering device for a vehicle of the present invention, even if the degree of reduction in steering force is controlled depending on the traveling state of the vehicle, if the traveling state is in a straight-ahead state, the reduction will be reduced under the same speed condition. For example, even if the road surface condition is bad and the steering force is turned, the strength of the steering force remains the same as long as the vehicle is traveling straight, so there is no discomfort and the steering force is extremely easy to use.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of a power steering device for a vehicle according to the present invention, FIG. 2 is a flowchart for explaining an example of its processing operation, and FIG.
The figure is a block diagram illustrating the basic configuration of the present invention. DESCRIPTION OF SYMBOLS 1...Control device, 2...Driving state detection means, 3...Power steering device, 4...Arithmetic control means, 5...Vehicle speed sensor, 6...Steering angle sensor, 7...Shift position sensor.

Claims (1)

[Claims] 1. Running state detection means including the running speed of the vehicle;
A power steering system for a vehicle, comprising: a power control means for controlling power of the steering system according to the detected running state, and adjusting a degree of reduction of steering force according to at least a running speed of the vehicle. Further, the power control means is configured to control the steering device when it is determined that the vehicle is in the turning state. 1. A power steering device for a vehicle, comprising a power correction means for making the power of the steering device smaller than the power of the steering device when the vehicle is determined to be traveling straight under the same speed condition. 2. The traveling state determining means includes: a steering angle detecting means for detecting a steering angle of the steering device; and a boundary angle of the steering angle that distinguishes between a straight-ahead state and a turning state of the vehicle, using the traveling state detecting means. a boundary angle calculating means that calculates a value that is smaller as the traveling speed increases, based on the calculated driving state; The power steering device for a vehicle according to claim 1, further comprising angle comparison means for determining the angle. 3. The driving state detection means includes a shift position detection means for detecting a shift position of the transmission of the vehicle, and the boundary angle calculation means calculates the shift position as the detected shift position becomes higher speed. 3. The power steering system for a vehicle according to claim 2, further comprising a boundary angle correction means for correcting the boundary angle to a small value.