JPS61285139A - Vehicle speed control device - Google Patents

Abstract

PURPOSE:To make it possible to control a high responsive vehicle speed with no hunching, by controlling the opening degree of a throttle valve in accordance with an absolute desired opening degree obtained by a P.I.D. control computation with a limited integrating time, on the basis of a desired vehicle speed determined in accordance with the operating amount of an accelerator. CONSTITUTION:A desired vehicle speed is obtained by a computing means (b) in accordance with the output of a means (a) for detecting the operating amount of an accelerator. A P (proportion). I (integration). D (differentiation). control computation is carried out by a means (d) for computing an absolute opening degree in accordance with the deviation between the desired vehicle speed and an actual vehicle speed which is sampled at closed intervals by an actual speed sampling means (c), in order to obtain the absolute desired opening degree for a throttle valve while a deviational integrating time for the integration control computation is limited to a set time by an integrating time control means (e). Further, a desired opening degree of the throttle valve for a constant speed running is obtained by means of a computing means (f) in accordance with the desired vehicle speed, and accordingly the opening degree of the throttle valve is controlled by means of a control means (g) on the basis of the abovementioned desired opening degree for constant speed running.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a vehicle speed control device that controls the speed of a vehicle in response to accelerator operation and also controls the vehicle speed to be constant regardless of the running load when the amount of accelerator operation is constant. It is something.

(Background of the Invention) In order to run a general vehicle at a constant speed, when the running load of the vehicle changes, such as when driving on a slope, it is necessary to adjust the amount of depression of the accelerator pedal according to the running load. , the adjustment operation becomes a burden for the driver.

Therefore, devices such as those disclosed in JP-A-50-4.3626 have been proposed, and according to these proposals, if the accelerator pedal depression is constant, the vehicle speed is controlled to be constant regardless of the vehicle's running load. This reduces the burden on the driver, and the effect of reducing the burden on the driver is particularly significant in vehicles with automatic transmissions.

FIG. 2 explains the vehicle speed control performed by this type of device. The deviation e of the actual vehicle speed from the target vehicle speed determined based on the amount of depression of the accelerator pedal is
is given to.

In the PID control system 10, the opening degree of the throttle valve is determined as the operation iu based on the equation.

This operation amount u is given to the vehicle 12, and the vehicle speed is controlled according to the operator (').

In the above equation, the value Kp represents a proportional control coefficient, the value K. represents an integral control coefficient, and the value K represents a differential control coefficient.

Furthermore, when driving at a constant speed, step-like changes in the target vehicle speed do not occur frequently, and deviations due to disturbances (driving value load) do not change in a step-like manner. Valve control is 100 m
It is carried out at intervals of 5 ec to 300 m5 ec.

Here, a microcomputer or the like is used in the PID control system 10, and its digital processing (as shown by the PTD control algorithm) is capable of performing digital processing.

u(n)=Kpe (nゝ''-KiMo. (i) aT where the value n indicates the number of sampling times, the value △ indicates the sampling interval, and the deviation e of the actual vehicle speed from the target vehicle speed.
It is 100m to sample and control the throttle valve.
It is carried out at intervals of 5ec to 30Q m5ec.

Roughly speaking, when running at a constant speed, the absolute opening of the throttle valve (slot interval is not required, and the larger the sampling period, the more the deviation e increases, making it easier to control the constant speed running, so 100 m5)
ec ~3 Q Q For each sampling performed at an interval of m5ec, the relative operation amount △u (n) is △LJ (n)
−Kp[e (n) −e (n−1) ], and each constant Kp in this equation is calculated as follows.

Ko is set to a relatively small value to prevent hanging.

However, when the accelerator pedal is operated to accelerate or decelerate the vehicle, the accelerator pedal operation speed at that time is full stroke / 100m5ec ~ 2QQmsec
Since it is a head, as mentioned above, 100m5ec ~ 3QQ
When the vehicle speed is sampled at msec intervals and the throttle valve is controlled, 1
No acceleration peak occurs between 00 m5ec and 200 m5ec, which gives the driver a sense of discomfort.

For example, time t in FIG. 3 (△). 1, when the accelerator pedal depression amount changes in a stepwise manner as shown by characteristic 100 during constant speed driving control, the throttle valve is gradually opened as shown by characteristic 102 in the same figure (C). As a result, the vehicle speed rises slowly from the previous target vehicle speed VT+ to the new target vehicle speed VT2, as shown by characteristic 104 in FIG.

For this reason, the accelerator pedal must be depressed more frequently, and therefore, in this conventional device, there has been a problem in that the effect of reducing the burden on the driver is reduced.

Therefore, as shown in the characteristic 106 of FIG. 3(C), an overshoe of the throttle valve opening degree of 1 to 1 is planned.
A device has been proposed that prevents the above control delay by controlling the vehicle speed as shown in characteristic 108 of B).

In this proposed device, the vehicle speed lean-pulling cycle is 1Q.
In addition to being set as short as msec to 50m5ec, the control gain of the throttle valve opening is increased by adjusting each control constant, Ki, and Kd, and as a result, the throttle valve has good responsiveness to the operation of the accelerator pedal. Opening/closing is controlled.

In this proposed device, since the sampling period of the vehicle speed is short and there is almost no change in the sampling vehicle speed while driving at a constant speed, it is difficult to control the throttle valve with the relative operation amount Δu (n). The control is performed according to the target opening degree, that is, the absolute operation @t-1(n>).

Furthermore, in the proportional control constant used for this control, the vehicle speed becomes constant and the deviation e (n) approaches the value ○ (= f
The differential control coefficient Kd is set to 8 times in one small shift in consideration of noise.

However, in this proposed device, if the accelerator pedal is depressed for 7J11 speed and then returned before the vehicle speed actually increases, the integral term will be added to the cumulative deviation e(n). Since the blade increases, there was a problem of hunting or occurrence.

For this reason, a second proposal has been made to limit the integration time to a finite value.

However, in this second proposed system, the deviation edge e(n) within a finite time when traveling at a constant speed.

When e (n-1>, -e (i) all have the value O,
Since the integral term KiΣe(i)ΔT i=k becomes the value O and the target opening of the throttle valve becomes the full opening, there is also the problem that hunting occurs.

(Object of the Invention) The present invention has been made in view of the above problems, and its object is to provide a vehicle speed control device that can control the vehicle speed with high responsiveness to the operation of the accelerator pedal without causing the hunting described above. It is about providing.

(Configuration of the Invention) In order to achieve the above object, an apparatus according to the present invention is configured as shown in FIG.

That is, in the same figure, the operation amount of the accelerator operator is detected by the accelerator operation amount detection means a, and the target vehicle speed has already been determined by the target vehicle speed calculation means based on the detected operation amount.

Then, the actual vehicle speed is sampled at close intervals by the actual vehicle speed sampling means C, and P(, proportional〉・I(integral〉)
- D (differential) control calculation is performed by absolute target opening calculation means d.

This determines the absolute target opening degree for the throttle valve, and the deviation integration time in the integral control calculation is limited to the set time by the integration time limiting means.

Furthermore, the target opening degree for constant speed driving of the throttle valve is determined based on the target vehicle speed by the constant speed driving target opening calculation means f, and the throttle valve opening/closing control means Ω uses the target opening degree for constant speed driving as a reference. Control is performed to open and close the throttle valve according to the absolute target opening.

(Description of Embodiments) Hereinafter, preferred embodiments of the apparatus according to the present invention will be described based on the drawings.

In FIG. 4, the amount of depression of the accelerator pedal 20 is detected by a potentiometer 22. In FIG.

In FIG. 5, an accelerator pedal 20 is rotatably supported by brackets 1 to 26 on a floor 24 in front of the driver's seat, and is biased counterclockwise by a return spring 28.

A potentiometer 22 is provided on the floor 24, and the amount of depression of the accelerator pedal 20 is detected by the potentiometer 22.

Furthermore, the detection signal of the potentiometer 22 is supplied to the A/D conversion circuit 32 of the vehicle speed control circuit 30 in FIG. Supplied.

The microcomputer 34 obtains a motor control signal based on the detection signal of the potentiometer 22, and the motor control signal is given to the servo driver 38 via the D/Δ conversion circuit 36.

This 1-no-vo driver 38 drives the step motor 40.
is controlled in accordance with a motor control signal, and the throttle valve 42 is opened and closed by a step motor 40.

A lever 44 is attached to the rotation shaft of the throttle valve 420 as shown in FIG.
The throttle valve 42 is biased (=I) by a return spring 46 in the closing direction.

Here, the vehicle speed is detected by the vehicle speed sensor 48 shown in FIG. 4, and the detection signal is sent to the microcomputer 34.
is supplied to.

The processing procedure of the microcomputer 34 is shown in a flowchart in FIG. 7, and the operation of this embodiment will be explained below using the flowchart.

The process shown in FIG. 7 is repeatedly performed in short cycles of 10 m5ec to 50 m5ec.
The input fi, e(n) is read (step 200>.): Then, the eighth data stored in the memory of the microcomputer 34 in the form of a table
From the characteristic 110 in the figure, the target vehicle speed VT (n> is determined using the accelerator pedal depression l (n>) (step 20
2) Furthermore, the actual vehicle speed V・detected by the vehicle speed sensor 48
(n> is read (step 204>, and the actual vehicle speed \/* (n) is subtracted from the target vehicle speed \/r (n>) to obtain the vehicle speed control (li difference e (n) (step 206 ).

This control deviation e(n) is equal to the control deviation e(n) in the previous cycle.
-1>, using constant IKp, Ki, Kd, and period ΔT, the absolute target opening degree 0A(n) of the throttle valve 42 is 0°(n) -Kpe (n) +K = ,5. ,
e (i >) (step 208)
, in that case, the integration time is a predetermined time Δd (n−k
): limited to.

1. Also, using the target vehicle speed VT (n), the target opening degree θe (n) for constant speed driving is determined from the characteristic 112 in FIG. 9 (stored in the memory of the microcomputer 30 in the form of a table). (step 210
).

Then, this constant speed running target opening θB (θ) and the absolute target opening θA (n>) are added to obtain the final target interval He○(n) of the throttle valve 42 (step 2'1
2>, a motor control signal corresponding to the target opening degree θo (n) is output to the servo driver 38.

As mentioned above, the actual vehicle speed Vi for the target vehicle speed VT (n>
The absolute target opening degree OA (n) for the throttle valve 42 is determined by performing a PID 1lil control calculation with a limited integration time based on the deviation e (n) of (n).
is determined, and a constant speed driving target for the throttle valve 42 is determined based on the target vehicle speed VT (n>):
Opening degree 0° (n)
t'p/constant speed running 14 marks 0° (n) e ゛shield 'vT'), Dyr) I, y valve 42 is at absolute target opening θA
Opening/closing is controlled according to (n).

The above-mentioned FIG. 10 explains the vehicle speed control operation of this embodiment based on the above processing. As shown in the figure ([), the vehicle travels at a constant speed at vehicle speed VT+, and then continues at a constant speed at a higher vehicle speed VT2. It is running.

Then, when the vehicle speed increases from vehicle speed VT+ to vehicle speed VT2, the depression of the accelerator pedal 20 1 (n) increases during the period from time 1o to time t1. Equivalent value 1. and time t, to time t? The value is 12 corresponding to the vehicle speed VT2, and the value is 1 during the period from time t2 to time t3.
．． After that, the value is kept constant at 12.

That is, in FIG. 10(A), the target vehicle speed V in FIG. 10(F)
After the accelerator pedal 20 is depressed by the amount 12 corresponding to T2, the return operation of the accelerator pedal 20 is performed before the target vehicle speed VT2 and the actual vehicle speed Vi match.

During this time, the control deviation e changes as shown by the characteristic 116 in FIG. changes as shown in characteristic 118 of .

Therefore, the throttle valve 42 is controlled to open and close as shown by characteristic 120 in FIG. 10(F), and the hunting does not occur at this time.

Also, when the deviation e becomes O, the absolute target opening degree OA
(n) converges to the value O corresponding to full opening of the throttle valve 42, but the target opening at that time is the target opening for constant speed running θB
Therefore, even in that case, the above-mentioned hunting will not occur.

Furthermore, when the accelerator pedal 20 is depressed again for acceleration at time t3 in FIG. Therefore, as can be understood from the characteristic 122 in FIG. 3(F), sufficient engine torque for acceleration can be obtained.

Furthermore, as shown by characteristic 12/1 in FIG. 10(B), when the running load of the vehicle changes due to running on a slope, etc., the throttle valve 42 is controlled to open as shown in FIG. 10(B). Therefore, as shown in the figure (), the vehicle speed is controlled to be constant to the target vehicle speed V2 determined by the accelerator pedal depression amount 12 at that time.

As explained above, according to this embodiment, the opening and closing of the throttle valve 42 is controlled according to the absolute target opening OA (n) based on the target opening θB for constant speed running, so the throttle valve 42 is controlled to open and close according to the absolute target opening OA (n). It becomes possible to increase or decrease the vehicle speed with high responsiveness depending on the operation.

(Effects of the Invention) As explained above, according to the present invention, the throttle valve is set based on the target vehicle speed determined by the accelerator operation amount in accordance with the absolute target opening obtained from the integral time or limited PID control latitude 1. Since the opening and closing are controlled as follows, it is possible to control the vehicle speed in response to the accelerator operation with high responsiveness without causing the hunting described above.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to complaints, FIG. 2 is an explanatory diagram of a vehicle speed control model, FIG. 3 is a characteristic diagram for explaining vehicle speed control operation, and FIG. 4 is a block diagram showing a preferred embodiment of the device according to the present invention. Fifth
The figure is a configuration diagram of the accelerator pedal attachment part, Figure 6 is a configuration diagram of the throttle valve attachment part, Figure 7 is a flowchart, Figure M8 is an accelerator pedal depression amount - target vehicle speed characteristic diagram, and Figure 9 is a diagram of target vehicle speed - target throttle. Valve opening degree characteristic diagram, FIG. 10 is a characteristic diagram explaining the operation of the embodiment of FIG. 4. a... Accelerator operation amount detection means b...
Target vehicle speed calculation means C...Actual vehicle speed sampling means d...
Absolute target opening calculation means e...Integration time limiting means f...Target opening calculation means for constant speed running q...
... Throttle valve opening/closing control means 20 ... Accelerator pedal 22 ... Potentiometer 30 ... Vehicle speed control circuit 38 ... Servo driver 40 ... Step motor 42 ... Throttle valve 48 ... Vehicle speed sensor patent Applicant Nissan Motor Co., Ltd.-! River θ

Claims (1)

[Claims] (1) Accelerator operation amount detection means for detecting the operation amount of the accelerator operator, target vehicle speed calculation means for calculating a target vehicle speed based on the detected operation amount, actual vehicle speed sampling means for sampling the actual vehicle speed at close intervals, and a target. Absolute target opening calculation means for calculating the absolute target opening for the throttle valve by performing proportional, integral, and differential control calculations based on the deviation of the sampled vehicle speed with respect to the vehicle speed, and limiting the deviation integration time in the integral control calculation to a predetermined time. an integral time limiting means; a constant speed running target opening calculation means for determining a constant speed running target opening of the throttle valve based on the target vehicle speed; A vehicle speed control device comprising: a throttle valve opening/closing control means for controlling opening/closing according to the speed.