JPH0121011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant speed driving system for automobiles, and more particularly, to a constant speed driving system for automobiles, which reduces the set vehicle speed in proportion to the degree of curvature of a road curve and the driving speed during automatic driving, thereby realizing safe driving. This relates to a fast running system.

In general, constant speed driving systems for automobiles set the value of the control signal to be supplied to the throttle actuator, such as the duty ratio of control pulses, in the auto drive mode, that is, the constant speed driving mode, set by the driver.The vehicle speed and the current vehicle speed are set. The configuration is such that the calculation is performed based on the above-mentioned set vehicle speed and the vehicle is driven at a constant speed.

Incidentally, the auto drive mode is generally selected while driving on a highway, and is suitable for reducing the driver's burden and effort. However, although expressways generally have straight sections for the most part, they also have a relatively large number of curved sections, so vehicles often enter curves in the set driving mode. In such a case, autodriving on a curve is dangerous, so the driver usually decelerates the vehicle by depressing the brake pedal. For this reason, autodrive is automatically canceled, and if you want to drive at a constant speed again after passing a curve at the preset vehicle speed before cancellation, you must perform a new resume operation to return to the preset vehicle speed.

The present invention has been made in view of the above points,
The purpose of the present invention is to provide a constant speed driving system for an automobile that does not require canceling the auto drive mode even when entering a curve from a straight section and can realize safe driving. Therefore, the present invention provides a constant speed driving system for automobiles that calculates the value of an actuator control signal based on at least set vehicle speed data and current vehicle speed data in auto drive mode to drive the vehicle at a constant speed. It is equipped with a steering angle sensor that outputs steering angle information and a calculation means, and the calculation means receives the steering angle information from the steering angle sensor during auto drive mode, and calculates the steering angle in proportion to the steering angle and the steering angular velocity. The present invention is characterized in that it is configured to reduce the set vehicle speed and decelerate the vehicle.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of a constant speed traveling system for an automobile according to the present invention.

In FIG. 1, 1 is a constant speed cruise control device, 2 is an actuator which is driven by a drive signal from the constant speed cruise control device 1 and adjusts the opening of a throttle valve (not shown), and 3 is a main switch. Constant speed running control device 1 from battery (not shown)
4 is a steering angle sensor that outputs steering angle information proportional to the steering angle, such as an analog voltage signal; 5 is a vehicle speed sensor, which is the output of a transmission (not shown); A switch disposed on the shaft outputs a pulse signal with a frequency proportional to the vehicle speed; 6 is a set switch which, when turned on, instructs the constant speed cruise control device 1 to enter auto drive mode;
Reference numeral 7 is a resume switch, which is mainly turned on to resume constant speed driving at the original set speed after the auto drive mode has been cancelled. Reference numeral 8 is a cancel switch, and a clutch switch (on manual vehicles). ), a neutral switch (for AT cars), a stop lamp switch, a parking brake switch, etc., each of which is used to cancel the auto drive mode.

Further, in the constant speed traveling control device, numeral 9 is a microcomputer which is the calculation means according to the present invention;
11 is a constant voltage circuit, 11 is a crystal oscillator, 12 is a reset circuit, 13 is an analog/digital converter that converts an analog voltage signal into digital information, that is, steering angle digital information, 14
represents an input buffer, and 15 and 16 represent output buffers, respectively.

Furthermore, in the actuator 2, 17 represents a control valve (not shown) for adjusting the negative pressure in the diaphragm chamber, and 18 represents a release valve that is maintained in a closed state during the auto drive mode.

When the main switch 3 is turned on, the microcomputer is applied with a constant voltage by the constant voltage circuit 10 and reset by the reset circuit 12 to start processing, and in synchronization with the clock signal from the crystal oscillator 11, the microcomputer starts processing as shown in FIG. A series of processes as shown in the flowchart are executed. First, the basic processing operation of each step in FIG. 2 will be explained.

In FIG. 2, 101 represents a step for initializing the various registers of the CPU in the microcomputer, the memory contents of the RAM, etc.

102 represents a step for calculating the current vehicle speed based on vehicle speed information from the vehicle speed sensor 5.

Reference numeral 103 represents a step for determining whether or not the auto drive mode is selected based on input signals from the set switch 6, the resume switch 7, and the cancel switch 8.

104 is a step of checking the θ change flag and determining whether or not the steering angle θ should be calculated. Note that this θ change flag is set to "1" at approximately 10ms intervals in the timer interrupt routine shown in Figure 3, which will be described later.
is set to .

105 represents a step for resetting the θ change flag to "0".

Reference numeral 106 represents a step for calculating the steering standard turning angle, that is, the absolute value _θB of the difference between the steering angle θ _S when the steering wheel is at the center position of the movable range and the current steering turning angle θ _A. Here, for example, the steering angle at the left turning end of the steering wheel is
It is expressed in hexadecimal notation as "00", and the steering angle at the end of right turn is similarly expressed as "FF", and the standard steering angle θ _S is "7F".
It is expressed as Therefore, as shown in FIG. 4, which schematically shows the movable range of the steering wheel, for example, when the steering wheel is at the illustrated position P, the standard steering angle θ _S , the current steering angle θ _A and the absolute value θ _B are respectively It will look like the one shown. Also, the absolute value θ _B is the same when the handle position is to the left from the center position.

107 is the absolute value θ _B calculated in step 106 above
and the angle θ _O of the dead zone area (hatched area shown in Figure 4) defined at a predetermined angle in the left and right turning directions from the handle center position, that is, the correction angle θ _C is calculated. represents the steps for

108 is the correction angle θ _C calculated in step 107 above.
represents the step of determining whether or not is a positive value. In other words, this step 108 is a step for determining whether the handle position is outside the dead zone area.

Reference numeral 109 represents a step for forcibly setting the correction angle θ _C to ``0'' when the determination result of step 108 is ``NO''.

110 is the correction angle θ _C calculated through the above steps 106, 107 and 108 or the above steps 106, 107,
Correction angle θ _C set to “0” through 108 and 109
This step represents the step of calculating the value obtained by dividing the absolute value of the difference between the correction angle θ _C-1 and the correction angle θ C-1 calculated in the previous θ calculation by a time width Δt of about 10 ms, that is, the steering angular velocity θ _D.

111 represents a step of calculating a changed set vehicle speed S _OC based on the correction angle θ _C calculated as described above, the steering angular velocity θ _D calculated in step 110, and the set vehicle speed S _O. That is, this step 111 calculates the changed set vehicle speed S _OC using the formula S _OC =S _O −K ₁ |θ _C |−K _{2 θD} . Here, in the above formula
K ₁ and K ₂ are each constant.

112 is a step for performing auto drive control (constant speed driving control). That is, this step 112
is the changed set vehicle speed _SOC , the current vehicle speed S calculated at step 102 in the current program execution,
Based on the previous vehicle speed S _-1 calculated in step 102 in the previous program execution, a predetermined calculation formula, namely D = D _O + G [S _OC - {S + K (S - S _-1 ) /
Δt}] to find the duty D of the control pulse to be supplied to the control valve 17. At the same time, the release valve 18 is maintained in a closed state. In this equation, D _O is the initial duty determined according to the set vehicle speed S _O , G and K are gain coefficients, and Δt is the time width for determining the acceleration.

Next, the processing operation of the entire flowchart shown in FIG. This will be explained separately.

(b) When the vehicle is in normal driving condition.

In this running state, the set switch 6 has not been turned on yet, so step 103 is performed.
The judgment result is always “NO” and the step
Only the closed loop consisting of step 102 and step 103 is repeatedly executed, and neither θ calculation nor autodrive control is performed.

(b) When the vehicle transitions from a normal vehicle driving state to an auto drive state and is in the auto drive state.

When the set switch 6 is turned from on to off under normal driving conditions,
The judgment result of step 103 is reversed to “YES”,
Next, step 104 is executed.

If the θ change flag has been reset to "0" at this point, the determination result at step 104 becomes "NO" and autodrive control is performed at step 112. That is, the current vehicle speed S calculated in step 102 is set as the set vehicle speed S _O , and the above formula D = D _O + G [S _OC - {S + K (S - S _-1 ) / Δt}]
The duty ratio is determined by D, and a control pulse signal having the duty ratio D is output to the output buffer 15. At this point, the vehicle speed has not yet been changed.
Since S _OC is not calculated, S _OC in the above formula
is replaced with the set vehicle speed S _O.

When the θ change flag is set to "1" by executing the timer interrupt routine shown in FIG. 3, the determination result at step 104 is "YES".
to be reversed.

Here, in the timer interrupt routine in Figure 3,
201 represents a step for saving registers.

202 represents a step of incrementing the RAM for the reference timer and also incrementing the RAM for counting the number of timer interrupts.

For 203, the value of RAM for counting the number of timer interrupts is "6"
represents the step of determining whether or not it matches.

204 represents a step of reading the A/D value from the analog/digital converter 13, that is, the steering angle digital information.

205 represents a step of setting the θ change flag to "1" and permitting θ calculation.

206 is the A/D read in step 204 above.
Set the value as the current steering angle θ _A , and
It represents the steps that apply to the parameters of step 110 shown in the figure.

207 represents a step for starting the analog/digital converter 13.

208 sets the value of RAM for counting the number of timer interrupts to "0"
Represents the step of resetting to .

209 represents a step for restoring the registers saved in step 201 above.

And this timer interrupt routine is for example 1.7
Executed in ms period, steps in approximately 10 ms period
204, 205, 206, 207 and 208 are executed sequentially.

As mentioned above, when the determination result at step 104 shown in FIG. 2 is reversed to "YES", the θ change flag is reset to "0" at step 105, and the
The absolute value θ _B is calculated in step 106, the correction angle θ _C is calculated in step 107, and it is determined in step 108 whether or not the correction angle θ _C has a positive value, and the judgment result is "YES".
If so, go directly to step 110, while
If the judgment result is “NO”, proceed to step 109.
After the correction angle θ _C is forcibly set to “0” in step 110, the correction angle θ _C and the previous correction angle θ set in step 206 shown in FIG. Steering angular velocity θ _D is calculated from _C-1 , and in step 111, the set vehicle speed S _O , the correction angle θ _C calculated in step 107, and the above step are calculated.
Based on the steering angular velocity θ _D calculated in step 110, the changed set vehicle speed _SOC is calculated, and the
The duty D is calculated based on the changed set vehicle speed _SOC , the current vehicle speed S calculated in step 102, and the previous current vehicle speed S _-1 . Subsequent steps
Every time the determination result in step 104 becomes "YES", the changed set vehicle speed _SOC is calculated, and the duty D corresponding to the changed set vehicle speed _SOC is calculated. Furthermore, the steps
If the judgment result in step 104 is "NO", the changed set vehicle speed _SOC is not calculated, and in step 112 the duty D corresponding to the immediately previous changed set vehicle speed _SOC is calculated.
is calculated.

After that, when a cancel instruction signal is input from the cancel switch 8, the judgment result at step 103 becomes "NO" again, θ calculation and auto drive control are no longer performed, and step 103 returns to "NO".
Steps 102 and 103 are executed repeatedly.

In this way, the microcomputer 9 performs the θ calculation in the auto drive mode, and calculates the duty D based on the changed set vehicle speed _SOC calculated by the θ calculation. and change setting vehicle speed
Since S _OC is given by the above formula, that is, S _OC =S _O −K ₁ |θ _C |−K ₂ θ _D ,
The larger the correction angle θ _C for the current steering angle θ _A , and the larger the steering angular velocity θ _D , the smaller the value of the changed set vehicle speed S _OC becomes.
The degree of decrease in vehicle speed increases.

As explained above, the present invention provides a constant speed driving system for an automobile in which the value of an actuator control signal is calculated based on at least set vehicle speed data and current vehicle speed data in auto drive mode to drive the vehicle at a constant speed. It is equipped with a steering angle sensor that outputs steering angle information proportional to the steering angle, and a calculation means, and the calculation means receives the steering angle information from the steering angle sensor during auto drive mode, and calculates the steering angle and steering angular velocity. The set vehicle speed is decreased in proportion to the vehicle speed, thereby decelerating the vehicle. Therefore, even if the car enters a curve while in autodrive mode, it is possible to decelerate the car according to the curve degree and angular velocity without canceling autodrive mode, and automatically return to the set vehicle speed after deceleration. As a result, safe driving can be maintained, and there is no need to perform a resume operation, which is normally performed after cancellation, and the burden on the driver can be reduced.

In the above embodiment, the analog/digital converter 13 is provided outside the microcomputer 9, but the analog/digital conversion may be performed by the microcomputer 9.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an embodiment of a constant speed driving system for automobiles according to the present invention, FIGS. 2 and 3 are flowcharts for explaining the processing operations thereof, and FIG. 4 is a diagram for explaining the present invention. Conceptual diagrams are shown. DESCRIPTION OF SYMBOLS 1... Constant speed cruise control device, 2... Actuator, 4... Steering angle sensor, 5... Vehicle speed sensor, 6... Set switch, 9... Arithmetic means (microcomputer), 13... Analog/digital conversion means.

Claims (1)

[Claims] 1. In a constant speed driving system for an automobile that calculates the value of an actuator control signal based on at least set vehicle speed data and current vehicle speed data in auto drive mode to drive the car at a constant speed, the steering angle is proportional to the steering angle. It is equipped with a steering angle sensor that outputs information and a calculation means, and the calculation means receives the steering angle information from the steering angle sensor during auto drive mode, and calculates the set vehicle speed in proportion to the steering angle and steering angular velocity. 1. A constant speed driving system for an automobile, characterized in that the constant speed driving system is configured to reduce the speed of the automobile and decelerate the automobile.