JPS62168728A - Duty control type constant speed traveling controller - Google Patents

Abstract

PURPOSE:To improve stability, by carrying out simultaneously a control which decreases the deflection of a car speed sharply and a control which makes the deflection of a car speed zero slowly, varying radically two integral elements in case that the acceleration of a car speed exceeds a prescribed value, and holding down the deflection of a car speed. CONSTITUTION:A control value is on-off controlled by an output duty D which is obtained from the control line of a prescribed incline, and a real traveling car speed Vn is approached to a stored target car speed VM. In the above apparatus, when G is designated for the incline of a control line, DELTAV for the deflection of a car speed, DM and SD1 for integral elements which respond to the change of the duty quickly and slowly, and (n) for a constant, a set duty SD corresponding to the target car speed VM is calculated by a formula SD=SD1+(DM-SD1)/n, and the output duty D is calculated by a formula D=GXDELTAV+SD. And when the acceleration of car speed DELTAVn exceeds a certain value, the DM and the SD1 are sharply varied at formulae DM DM-A.DELTAVn and SD1 SD1-B.DELTAVn.

Description

[Detailed Description of the Invention] C. Industrial Application Field] The present invention relates to a duty control type constant speed cruise control device, and in particular to a device for controlling the difference between a set vehicle speed and an actual vehicle speed (hereinafter referred to as vehicle speed deviation ΔV) to zero. In order to achieve this, two integration elements, fast integration element 1 and slow integration element 2, are provided, and control to rapidly reduce the vehicle speed deviation and control to gently reduce the vehicle speed deviation to zero are simultaneously performed, and the vehicle speed acceleration is controlled to a certain value. If the value exceeds , these two integral elements are rapidly changed in accordance with the acceleration in an attempt to reduce the change in vehicle speed.

[Conventional technology]

In a duty control type constant speed driving control device, the duty value required to travel at a constant speed at the target vehicle speed (set vehicle speed) is set as the set duty, and the duty amount according to the difference between the target vehicle speed and the traveling vehicle speed is set as the set duty. It performs constant speed driving control while adding or subtracting the value and outputting the result. but,
The required duty amount changes depending on variations in the characteristics of the actuator, throttle drive system, and engine, road slope, the presence or absence of engine loads such as air conditioners, and changes in vehicle loads such as transmission gears.If the set duty is fixed, the required duty amount A vehicle speed deviation occurs depending on the difference between the two.

Figure 6 is a system configuration diagram showing an example of this type of constant speed running control device.The controller ECU is a vehicle speed sensor equipped with a reed switch that is turned on and off by a magnet that rotates in proportion to the rotation of the vehicle drive shaft. The speed of the vehicle is detected based on the signal. The ECU memorizes the traveling vehicle speed when the cent switch is turned on, and controls the control valve of the actuator ACT on a duty basis after the cent switch is turned off. When the control valve is ON, negative pressure is introduced, increasing the force generated by the diaphragm linked to the throttle SL. When it is OFF, the atmosphere is introduced and weakens the diaphragm generating force. During this time, the release valve is turned on to shut off the atmosphere. When a cancel signal (clutch switch (neutral start switch for A/T vehicles), parking switch, or brake switch) is input, both the control valve and release valve are turned OFF, atmospheric air is introduced from both, and control is immediately stopped. let When the resume switch is turned on after cancellation, the travel control at the previously memorized vehicle speed is restored.

A microcomputer is used for the ECU, and the processing therein is divided into blocks as shown in Fig. 7. The output duty D for controlling the control valve on and off is determined according to the difference between the target vehicle speed vM stored in the memory and the traveling vehicle speed Vn, but in detail, it is not the traveling vehicle speed Vn itself, but the vehicle speed change component < * minute component. ) is used as the skip vehicle speed Vs. This is to advance and compensate for dead time due to actuator delay, throttle, and drive system hysteresis and play. Therefore, the skip vehicle speed Vs is determined by the following equation.

Vs=Vn+Kx (Vn-V, 1-1) -(
1) Also, the output duty D is determined by the following equation.

D=GXΔV + S Do...
...(2) [Problem to be solved by the invention] The above-mentioned constant speed cruise control device has a problem that the eighth
The output duty D is changed on the control line shown in the figure to try to converge the vehicle speed to the set vehicle speed VM. The slope of this control line is the gain G. The important point in this control is that
The main purpose of control is to maintain the set vehicle speed. However, the conventional system only has one duty (the aforementioned set duty SD a) that should be the center of control, or only has a duty that corresponds only to the vehicle speed.
In reality, the occurrence of vehicle speed deviation ΔV could not be avoided due to the need to take various values depending on the vehicle, road surface9 weight, vehicle speed, etc.

For example, as shown in Figure 8, if duty A is required to drive at a certain set speed, the vehicle speed will decrease along the line until it travels at point B, where the duty and vehicle speed are balanced. This vehicle speed difference remains as a set deviation. Therefore, the state in which such a vehicle runs at a constant speed is as shown in FIG. 9, and the running speed changes depending on the road load.

The set deviation mentioned above becomes O if the control line is corrected so as to pass through the 0 point. The present invention proposes one such method.

[Means for solving problems]

In the present invention, a control valve of an actuator that adjusts the throttle opening is controlled on and off using an output duty D obtained from a control line with a predetermined slope indicating the conversion characteristics between vehicle speed and duty, and the actual traveling vehicle speed is memorized. In a duty control type constant speed cruise control device that approaches a target vehicle speed, the set duty SD corresponding to the target vehicle speed is calculated as 5D=SD 1 + (DM-5D I)/n, and the output duty D is calculated as r )=GXΔV+SD, and when the vehicle speed acceleration ΔVn exceeds a certain value, the correction formula is DM4-DM-A-ΔVn SDI-3DI-B・ΔVn (A, B: constant (unit: % duty/acceleration) Then suddenly change the DM and SDI, and set the corresponding set date S.
The present invention is characterized in that it includes a controller that integrally corrects D in a direction toward the output duty D.

[Effect]

In the present invention, the output duty D is D=GXΔV+SD (
Calculate in 3). SD is a variable set duty, and S
D = SDI + (DM - SDI)
/ n −+4). DM is a high-speed integral element that has the function of quickly responding to changes in duty (also known as changes in vehicle speed) and reducing center deviation. The operating concept is to rotate the control line at high speed in a direction that reduces the deviation, as shown in FIG. 1(a).

On the other hand, the SDI is a low-speed integral element and has the function of responding slowly to changes in duty and reducing set deviation. The concept of operation is to move the control line in parallel in a direction that reduces the deviation, as shown in FIG.

The initial values of both DM and SDI correspond to SDo in equation (2),
As the duty D changes, it changes as shown in FIG. FIG. 4(a) shows an example of the operation when the vehicle speed decreases (duty increases) as the vehicle moves from a flat road to an uphill road, and FIG. 2(b) shows an example of the operation including a downhill slope. As shown in the same figure (al), when the duty D changes with the change in vehicle speed, DM, SD
Both I start to change, but since DM has a faster response, D'M follows first.

Then, since the SDI follows with a delay, the overall SD is 1
It changes as shown by the dotted chain line and eventually matches the duty D. This is because SD moves from SDo to D=A,
At this time, equation (3) is stabilized with ΔV=O and 5D=A.

The output duty D is (31 (from formula 41, D=G\, Δv
+ (S01 + (DM-SD1) /n)...
...(5) It is expressed as.

FIG. 3 is a basic flowchart of the present invention, and corresponds to the block diagram of FIG. 7. In this example, the fast integral element D
M is changed in proportion to the difference from duty D. That is, DM(il-DM(H-1)
+α ...... (6) When changing the current element DM (il by α from the previous DM (H1)), for example, α = (D(11-DM(+-x)) /' K
......(7), then the current duty D
The correction speed is made variable by reflecting the difference between (i) and the previous element DM(11) (K is a constant).

On the other hand, the slow integral element SDI uses a variable β smaller than α and calculates S D 1 (i) − S D 1 (i−t) +
It is expressed as β (8), but if this β is set to a fixed value, the correction speed will be constant. For example, when D > SDI, β = 0.2% (i-
1) (il) When D(H-1) < S D I (+1), β=
-0.2%.

Once the DM and SDI at each point in time are determined in this way, SD is calculated by substituting them into equation (3), and duty D is calculated by substituting them into equation (4).

By the way, the above-mentioned control method uses a fast integral element 1 (DM) and a slow integral element 2 according to the movement of the duty.
The system uses a method of calculating duty centered on the midpoint of (SDI), and aims to respond to road surface fluctuations by fast movement of the integral element, but under normal driving conditions, the DM movement is too fast. If this happens, the gain becomes too large, leading to vehicle speed hunting, making it impossible to move very quickly. For this reason, when a quick response such as a sudden change is required, control tends to be delayed if left as is, resulting in excessive overshoot or undershoot of the vehicle speed. Therefore, in the present invention, when the vehicle speed acceleration ΔVn exceeds a certain value, a value proportional to the acceleration is subtracted from each integral element to provide quick response to sudden changes and prevent control delays.

Specifically, A・ΔVn is subtracted from DM, and SDI
Subtract B·ΔVn from . A and B are constants, and the unit is % duty/acceleration.

〔Example〕

FIG. 4 is a flowchart showing one embodiment of the present invention, in which processing within the dashed line frame is added to the flow of FIG. 3.

In this example, DM-DM-A-ΔV n −” −(
9], A=4, and 5DI-3DI-B・ΔV n, =...=
Since B=1 at αω, if the acceleration ΔVn exceeds, for example, 1.25 km/h/sec, DM
4·ΔVn is subtracted from , and ΔVn is subtracted from SDl. As a result, DM and SDI change rapidly.

However, since ΔVn takes a positive sign during acceleration and a negative sign during deceleration, use DM when lowering the duty.

Both SDl decreases, and conversely, when increasing, both DM and SDl increase.

FIG. 5 is an explanatory diagram of this operation, in which (a) is based on the basic method shown in FIG. 3, and (b) is based on the improved method shown in FIG. 4. The duty change shown in FIG. 6(b) is more steep than that shown in FIG. 4(a), and as a result, even if the road surface gradient changes suddenly, the change in vehicle speed can be suppressed to a small value.

〔Effect of the invention〕

As described above, according to the present invention, when it is necessary to move the set duty due to changes in the road surface, etc., the dynamic gain is increased by moving the element DM, and the element SDI is moved while keeping the vehicle speed deviation small. This makes it possible to reduce vehicle speed deviation to zero while suppressing fluctuations in vehicle speed. Furthermore, since DM and SDI are changed in proportion to the acceleration when the acceleration exceeds a certain value, it is possible to suppress the vehicle speed deviation to a small value even when the road surface gradient changes suddenly, and to ensure stable controllability.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is an explanatory diagram of the operation of the present invention, Fig. 3 is a basic flowchart of the invention, Fig. 4 is a flowchart showing an embodiment of the invention, and Fig. 5 is a diagram illustrating the operation of the invention. Third
6 is a system configuration diagram of the duty control type constant speed traveling device, FIG. 7 is a block diagram of its microcomputer processing, FIG. 8 is a characteristic diagram of conventional duty control, and FIG. FIG. 9 is an explanatory diagram of the operation. In the figure, E (jJ is the controller, ACT is the actuator, S
L is the throttle.

Claims (1)

[Claims] A control valve of an actuator that adjusts the throttle opening is controlled on and off by an output duty D obtained from a control line with a predetermined slope indicating a conversion characteristic between vehicle speed and duty, and the actual traveling vehicle speed is stored. In a duty control type constant speed cruise control device that approaches a target vehicle speed, the set duty SD corresponding to the target vehicle speed is calculated as SD=SD1+(DM-SD1)/n, and the output duty D is calculated as D=G. ×ΔV+SD {G: Gradient of control line ΔV: Vehicle speed deviation DM: Integral element that responds quickly to duty changes SD1:
An integral element that responds slowly to duty changes: n: constant}. Furthermore, when vehicle speed acceleration ΔVn exceeds a certain value, DM←DM-A・ΔVn SD1←SD1-B・ΔVn {A, B: constant (unit DM and SD1 are suddenly changed using the correction formula (% duty/acceleration), and the set data S
A duty control type constant speed travel control device, comprising a controller that integrally corrects D in a direction approaching an output duty D.