JPH10250408A - Control method of constant speed traveling device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the effect of load fluctuation by providing target acceleration data table which increases a value when a deviation between actual car speed and target car speed is large and reduces a value when the deviation is small, calculating each acceleration from actual car speed and the target acceleration data table, and controlling an actuator so that both of them agree. SOLUTION: Target acceleration is determined in accordance of a deviation of car speed and is set on a table in such a manner that target acceleration is increased or decreased in accordance with increase or decrease of the deviation of car speed. As target for control, memory car speed is set, and actual car speed and vehicle acceleration are calculated based on values detected by a car speed sensor. The change of vehicle acceleration is calculated based on the actual acceleration which is calculated previously and a value which is calculated this time, a deviation of car speed is obtained based on memory car speed and actual car speed, target acceleration which corresponds to the deviation of car speed is obtained based on the target acceleration table, and an actuator control amount which determines a degree of opening of a throttle valve is calculated. Since uncomfortable feelings are given due to the repetition of fuel cut in the control in the direction of deceleration, the throttle valve is fully closed when the deviation exceeds a predetermined deviation so that the control which is not affected by load fluctuation can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a constant speed traveling device for a vehicle.

[0002]

2. Description of the Related Art As a conventional method for controlling a constant speed traveling device for a vehicle, a vehicle speed sensor detects an actual vehicle speed, stores the actual vehicle speed at the start of constant speed traveling as a target vehicle speed for constant speed traveling, and stores the target vehicle speed. The vehicle speed control area is divided into a feedback area consisting of a relatively narrow vehicle speed range above and below, a constant acceleration control area equal to or lower than the lower limit vehicle speed of the feedback area, and a deceleration control area equal to or higher than the upper limit vehicle speed of the feedback area. Separately, a dedicated control formula is provided to control the throttle opening via an actuator with a calculated control value.

[0003] In such a vehicle constant speed traveling device, when the vehicle speed is in the feedback area, a value obtained by multiplying the vehicle speed deviation between the target vehicle speed and the actual vehicle speed by a constant and a value obtained by multiplying the vehicle acceleration by a constant are used. The sum is taken as the control amount (PD
Control), when the vehicle is in the constant acceleration control area, a value obtained by multiplying the vehicle speed deviation between the target acceleration and the vehicle acceleration by a constant is used as a control amount, and when the vehicle is in the deceleration control area, the throttle valve is operated to be fully closed. There is.

[0004]

However, in the above-mentioned prior art, areas are divided into target vehicle speeds and control is performed for each area by a dedicated control method. In addition, since there are dedicated control constants for each area, it is complicated to determine these according to the characteristics of the vehicle, and the control amount becomes discontinuous when the actual vehicle speed exceeds the boundary of the area. The problem is that the actual vehicle speed does not agree with the target vehicle speed because the load fluctuations (vehicle weight changes, road gradients, variations in actuator characteristics, etc.) are significant as PD control characteristics. There was a problem that there is.

[0005]

SUMMARY OF THE INVENTION In order to solve such a problem, and particularly to reduce the influence of a load change, the present invention determines the actual vehicle speed detected by a vehicle speed sensor. In a control method for a constant-speed traveling device for a vehicle in which a throttle valve is driven by an actuator to control a throttle opening so as to match a target vehicle speed during high-speed traveling, a vehicle speed deviation between the actual vehicle speed and the target vehicle speed is large. In this case, a target acceleration data table in which a target acceleration is set to be large and a small value is set when the vehicle speed deviation is small is provided, the actual vehicle speed is stored, and a target corresponding to the vehicle speed deviation is stored from the target acceleration data table. The acceleration of the vehicle is calculated, and the actual acceleration of the vehicle is calculated from the current detected vehicle speed and the previously stored actual vehicle speed. Calculates a target acceleration corresponding to the vehicle speed deviation from the table and the actual acceleration and controls said actuator so as to coincide with the target acceleration.

[0006] Thus, since control is performed so that the actual acceleration matches the target acceleration calculated from the target acceleration data table, different controls such as a feedback control area and a constant acceleration control area are performed according to the magnitude of the vehicle speed deviation. Since there is no need to provide separate areas, continuous control can be performed until the vehicle speed matches the target vehicle speed. In addition, the control of the actuator is performed by PDI control, the P term is calculated from the difference between the target acceleration and the actual acceleration, and the D term is calculated by differentiating the actual acceleration.
By calculating the term by integrating and calculating the difference between the target acceleration and the actual acceleration, the above control can be suitably performed with a simple calculation formula.

As described above, the target acceleration corresponding to the vehicle speed deviation is obtained from the target acceleration table, and the target acceleration is made to match the actual acceleration. Therefore, the control amount can be calculated by the same formula at any vehicle speed. Therefore, there is no boundary due to the division of the control vehicle speed range, and there is no sense of incongruity due to discontinuity when passing through the boundary.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to specific examples shown in the accompanying drawings.

FIG. 1 is a diagram showing a target acceleration data table to which the present invention is applied. In this constant speed traveling control, an ideal approach characteristic in which the actual vehicle speed V approaches the memory vehicle speed Vm as the target vehicle speed at the time of constant speed traveling as shown in the figure is set in advance. Then, a target acceleration (α1 in the figure) is determined according to a vehicle speed deviation (ε1 to ε6 in the figure) at an arbitrary time with respect to the memory vehicle speed Vm.
~ Α6) is determined, and as shown in the figure, the target acceleration is large when the vehicle speed deviation is large, and is set on the table so that the target acceleration decreases as the vehicle speed deviation decreases.

Next, the control according to the present invention will be described below with reference to the flowchart of FIG. First, the first step ST1
In step ST2, the actual vehicle speed Vn is calculated from the value detected by the vehicle speed sensor. In the next third step ST3, the vehicle acceleration αn at the time of calculating the current actual vehicle speed Vn is calculated using the previous actual vehicle speed Vn-1.

In the next fourth step ST4, the change in the vehicle acceleration (the jerk) at the time of calculating the current actual vehicle speed Vn is calculated from the actual acceleration αn calculated in the third step ST3 and the actual acceleration αn-1 calculated last time. dαn) is calculated. In the next fifth step ST5, a vehicle speed deviation εm is calculated from the memory vehicle speed Vm and the actual vehicle speed Vn. In a sixth step ST6, a target acceleration αm corresponding to the vehicle speed deviation εm is obtained based on the target acceleration table set as shown in FIG.

In this constant speed traveling control, the actuator control amount ΔTHn for determining the opening degree of the throttle valve is required to perform the PDI control, and is calculated by the following equation.

ΔTHn = −P · (αn−αm) −D · dαn−I · Σ (αn−αm) (1)

Here, the first term on the right side is a proportional term, and P
Is the target value (target acceleration αm) and control value (actual acceleration αn)
Is the coefficient of the difference from The second term on the right side is a differential term, and D is a coefficient of a differential value of the control value (actual acceleration αn). The third term on the right side is an integral term, and I is a coefficient of an integrated value of a difference between a target value (target acceleration αm) and a control value (actual acceleration αn).

The value of each term of the PDI is calculated in the seventh step S
It is calculated at T7. Then, in an eighth step ST8, the control values calculated in the seventh step ST7 are substituted into the above equation (1) to calculate an actuator control amount ΔTHn.

The actuator control amount ΔTHn
Is the current change of the throttle opening from the previous time, but does not perform feedback control of the throttle opening. For example, the DC motor or negative pressure type actuator is the energizing time, and the actuator using the step motor is used. Then, it becomes the number of steps of the step motor.

Generally, when controlling in the deceleration direction,
Depending on the setting of the target acceleration, the fuel cut and the return thereof are repeated due to the characteristics of the engine, which causes discomfort to the occupant. In order to prevent this, the deceleration-side target acceleration table is set as shown in FIG. 3, so that the throttle valve can be completely closed to prevent discomfort to the occupant.

In the setting of the control shown in FIG. 3, as shown in the figure, when the vehicle speed deviation becomes equal to or more than a predetermined value on the deceleration side, the target acceleration is set to the maximum value -αmax, and the full-close control is reliably performed. I'm trying to get.

[0019]

As described above, according to the present invention, the actuator is controlled at a constant speed so that the actual acceleration matches the target acceleration by using the target acceleration calculated from the target acceleration data table in accordance with the vehicle speed deviation. Therefore, it is not necessary to divide the control vehicle speed range according to the magnitude of the vehicle speed deviation from the target vehicle speed (memory vehicle speed), and it is possible to perform control with a smaller number of constants used for determining the control value. Since there is no boundary due to the division of the vehicle speed range, the control amount can be calculated by the same formula at any vehicle speed, so that continuous control is possible, and there is no sense of incongruity due to discontinuity when passing through the boundary. Furthermore, by setting the target acceleration so that the actual vehicle speed decreases as the vehicle speed approaches the target vehicle speed, the actual vehicle speed is always equal to the target vehicle speed, and constant speed running control that is not affected by load fluctuations is performed. Can be.

Further, the actuator is controlled by PDI control, the P term is calculated from the difference between the target acceleration and the actual acceleration, the D term is calculated by differentiating the actual acceleration, and the I term is calculated from the target acceleration and the actual acceleration. The above control can be performed with a simple calculation formula by calculating the difference by integrating and calculating, and the control for matching the actual acceleration to the target acceleration can be suitably performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a target acceleration data table to which the present invention is applied;

FIG. 2 is a flowchart showing control based on the present invention.

FIG. 3 is a diagram showing another characteristic of the target acceleration table.

Claims (2)

[Claims] 1. A control method for a vehicle constant-speed traveling device that controls a throttle opening by driving a throttle valve by an actuator so that an actual vehicle speed detected by a vehicle speed sensor matches a target vehicle speed during constant-speed traveling. In the above, there is provided a target acceleration data table that sets a target acceleration that is large when the vehicle speed deviation between the actual vehicle speed and the target vehicle speed is large and small when the vehicle speed deviation is small, and stores the actual vehicle speed. Calculating a target acceleration corresponding to the vehicle speed deviation from the target acceleration data table; calculating an actual acceleration of the vehicle from the currently detected actual vehicle speed and the previously stored actual vehicle speed; Calculate the target acceleration corresponding to the vehicle speed deviation from
A method of controlling a constant speed traveling device for a vehicle, wherein the actuator is controlled so that the actual acceleration matches the target acceleration. 2. The control of the actuator is performed by PDI control, a P term is calculated from a difference between the target acceleration and the actual acceleration, a D term is calculated by differentiation of the actual acceleration, and an I term is calculated by the target acceleration. The method according to claim 1, wherein the difference between the acceleration and the actual acceleration is calculated and calculated.