JPS62168734A - Duty control type constant speed traveling controller - Google Patents

Abstract

PURPOSE:To prevent a hunting immediately after a target car speed is set up, by fixing the correction term of a set duty to constant values which are different from each other in car speed ranges for a prescribed time after the target car speed is set up. CONSTITUTION:The entitled device calculates a skip car speed Vs by adding an acceleration which is obtained by differentiating a traveling car speed Vn to this traveling car speed Vn which is obtained from a car speed signal. And a control valve for controlling the opening of a throttle is controlled by calculating on output duty D from a gain G, a set duty SD and a deflection DELTAV between the car speed Vs and a target car speed (stored car speed) VM. The set duty SD is determined using an integral element SD1 which responds to the change of a duty slowly and another integral element DM which responds thereto. In this case, the another integral element DM which responds thereto. In this case, the correction term beta of the SD1 is fixed to constant values which are different form each other in car speed ranges for a prescribed time after the target car speed is set up, thereby an integral speed is restrained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a duty control type constant speed cruise control device that integrally corrects a set duty corresponding to a target vehicle speed.
Particularly, this is intended to prevent λ-nching immediately after the target vehicle speed is set.

[Conventional technology]

A duty control type constant speed driving control device uses the duty value required to travel at a constant speed at the target vehicle speed as the set duty, and adds or subtracts the duty amount according to the difference between the target vehicle speed and the traveling vehicle speed to or from the set duty. It performs constant speed driving control while outputting the same amount of power. However, the required duty amount changes depending on variations in the characteristics of the actuator, throttle drive system, and engine, road surface slope, the presence or absence of engine loads such as air conditioners, and changes in vehicle loads such as transmission gears. A vehicle speed deviation occurs according to the difference with the duty amount.

Figure 4 is a system configuration diagram showing an example of this type of constant speed cruise control device.The controller ECU is connected to 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. When the set switch is turned on, the ECU memorizes the traveling vehicle speed, and after the set switch is turned off, it controls the control valve of the actuator ACT on a duty basis. When the control pulse is turned 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 (A/Ti is a neutral start switch), parking switch, or brake switch) is input, the control valve II
Turn off both JIJ and Subaru, introduce atmospheric air from both, and immediately stop control. 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. The output duty D for controlling the control valve on and off is determined according to the difference between the target vehicle speed (memory vehicle speed) VM and the traveling vehicle speed Vn, but in detail, it is not the traveling vehicle speed Vn itself but the vehicle speed change component (differential component). The added skip vehicle speed Vs is used.

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 S is determined by the following equation.

Vs = Vn +K (Vn-Vn-1)
・”-(1) Also, the output duty D is obtained by the following equation.

Since VM-VS in the above equation is the vehicle speed deviation Δ■, and the control speed width VB is the reciprocal of the control gain (gradient of the control line) G, equation (2) can also be expressed as follows.

D=GXΔV+SD ・・・・・・
(3) By the way, if the reference value of the duty amount required for constant speed running is fixed as a set duty, vehicle speed deviation will occur due to variations in the actuator system and vehicle load fluctuations. For example, as shown in Fig. 6, if the set duty SD corresponding to the stored vehicle speed VM (e.g. 80 Km/h) is 40% and the required duty iD is 55%, the control center at point A is initially set to duty. Due to the shortage, the vehicle speed converges to point B as the vehicle speed decreases. Since the required duty amount at point B is also approximately 55% (in detail, as shown by the dashed line, the required duty amount has a vehicle speed coefficient of approximately 0.1%/Km/h, but it is almost ignored in this example. can)
, if the control speed width vB is, for example, 20 Km/h, then 2
A deviation of 0 X -= -3 Km/h occurs, and the speed is controlled at 77 Km/h at point B.

Such a vehicle speed deviation can be reduced to O by correcting the control center from point A in FIG. 6 to point 0. For this purpose, the control line in the figure may be moved in parallel from the solid line position to the broken line position.

One of these methods is to change the correction speed depending on the magnitude of the difference ΔD between the output duty D and the set duty SD.

The equation below is a modified equation based on the above method, and the correction term β takes the values shown in Table 1.

5D=SD+β ・・・・・・(
4) Table 1 [Problems to be solved by the invention] By the way, constant speed driving control starts by pressing a set switch while driving and storing the traveling vehicle speed at that time as the target vehicle speed. A large duty fluctuation occurs. For this reason, if the same control as that during subsequent constant speed driving is performed, the movement of the SD may be too fast and the vehicle speed hunting as shown in FIG. 2(b) may be prolonged. The present invention attempts to improve this point.

[Means for Solving the Problems] The present invention turns on and off a control valve of an actuator that adjusts the throttle opening using an output duty D obtained from a control line with a predetermined slope that indicates the conversion characteristics between vehicle speed and duty. When the actual traveling vehicle speed approaches the stored target vehicle speed, the control line is moved in parallel at an integral speed according to the difference ΔD between the set duty SD corresponding to the target vehicle speed and the output duty D. In a duty control type constant speed cruise control device equipped with a controller that integrally corrects the set date SD in a direction approaching the output duty D, a correction term of the set duty SD is used for a certain period of time after the target vehicle speed is set. This is characterized in that the integral speed is limited by fixing β to a constant value that varies in the vehicle speed range.

[Effect]

Immediately after setting the target vehicle speed, the previous state is not known, so if the value of the correction term β is selected from Table 1, it may be too large. Therefore, in the present invention, the value of β is limited to a constant value that provides a slow integration speed for a certain period of time after setting (for example, 14 seconds). In addition, by varying this value depending on the vehicle speed range, optimization is achieved taking into account differences in vehicle gain.

〔Example〕

FIG. 1 is a flowchart showing one embodiment of the present invention. The SD correction method in this example uses two integral elements DM and SDI, and 5D=SD I + (DM-3D I)/n・(5)
It is expressed as DM is a fast integral element, DM=DM+α
......(6), and the correction term α is expressed as, for example, α=(D-DM)/K...(
7), it becomes the average value of the output duty D.

On the other hand, SDI is a slow integral element, and SD I =SD 1+β...
It is expressed as (8).

The initial value of DM, SDI, and SD is SDo, which changes following the duty D as shown in FIG.

SDI is an element that moves the control line in FIG. 6 in parallel, whereas DM is an element that rotates the control line around point A toward the zero point. The method explained in Table 1 is a one-element integration method that does not use this DM, so the SDI of the two-element force formula
If used, equation (4) has the same meaning as equation (8).

In the flowchart of FIG. 1, the control is changed within 12 seconds and after the setting. In other words, after 12 seconds, D
β is determined according to the magnitude of -3D, but within 12 seconds, the vehicle speed range is taken into consideration, and β is uniquely determined from the magnitude relationship of SD. In other words, in the low speed range below 60km/h, β = ±0.0
4%/sec, + when D>SD, - when D≦S
It's time for D.

In the high range exceeding 60 Km/h, β = ±0.2
%/sec, β is determined regardless of the size of D-3D. At this time, β is used to set the integral correction speed to a gentle constant value.

Once β is determined, S'DI is calculated using equation (8),
In the method using DM, DM is calculated using equation (6), then SD is calculated using equation (5); if DM is not used, SD is calculated using equation (4)), and then duty D is calculated using equation (1). and output it. One cycle of this flow is, for example, 50
It is m5ec.

Figure 2 (Al is an explanatory diagram of the operation of the present invention; by keeping the SDI correction speed at a gentle constant speed until a certain period of time T has elapsed after setting, the amount of change in other factors accompanying changes in duty is suppressed. As a result, the occurrence of hunting as shown in the same figure (bl) can be prevented.

〔Effect of the invention〕

As described above, according to the present invention, there is an advantage that hunting can be prevented immediately after the target vehicle speed is set in a duty control type constant speed cruise control device that integrally corrects the set duty.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
Fig. 3 is an explanatory diagram of its operation, Fig. 3 is an explanatory diagram of the two-element integral correction method, Fig. 4 is a system configuration diagram of the constant speed cruise control device,
FIG. 5 is a block diagram of the microcomputer processing, and FIG. 6 is a characteristic diagram of duty control. In the diagram, ECU is a controller, ACT is an actuator, and SL
is the throttle. Applicant: Fujitsu Ten Ltd. Applicant: Toyota Motor Co., Ltd. Representative Patent Attorney Minoru Aoyagi 6 = Kuto N ←C1-8 ←Shojo

Claims (1)

[Claims] The control valve of the 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 that indicates the conversion characteristics between vehicle speed and duty, and the actual traveling vehicle speed approaches the stored target vehicle speed. When setting the set duty SD corresponding to the target vehicle speed.
and the output duty D, the controller moves the control line in parallel at an integral speed according to the difference ΔD between the set data SD and the output duty D, and integrally corrects the set data SD in a direction approaching the output duty D. In a constant speed cruise control device,
A duty control type constant speed cruise control device, characterized in that, for a certain period of time after setting the target vehicle speed, the correction term β of the set duty SD is fixed at a constant value that varies in the vehicle speed range to limit the integral speed.