JPH01145235A - Constant speed traveling controller for vehicle - Google Patents

Abstract

PURPOSE:To maintain the convergence performance to an aimed car speed and improve the responsiveness in the constant speed traveling control independently of the difference of the speed change stage by varying a part of the control gain without destroying the balance of the whole feedback control system. CONSTITUTION:The actual car speed is detected by a means A, and the car speed is adjusted by a means B. Further, on the basis of the detected car speed, the means B is controlled by a means C by using a control value obtained on the basis of a prescribed equation having at least a negative feedback differentiation value, and feedback control is performed so that the actual car speed becomes equal to an aimed car speed. While, the speed change stage is detected by a means D. The control gain for the negative feedback differentiation term is varied by a means E on the basis of the detected speed change stage. Therefore, a part of the control gain is varied without destroying the balance of the whole feedback control system, and the convergence performance to an aimed car speed can be maintained independently of the difference of the speed change stages.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a constant speed cruise control device for heavy vehicles.

(Prior Art) Many recent vehicles are equipped with a constant speed cruise control device that automatically controls the vehicle speed to a target vehicle speed set by the driver.

In such a constant speed running control device for a vehicle, it is common to feedback control a heavy speed adjustment means such as an engine throttle valve based on the output from a vehicle speed detection means that detects the actual vehicle speed. .

By the way, when performing constant speed running control, if the gears are different, the magnitude of the engine margin torque will be different, and the convergence to the target heavy speed will be different for each gear. In order to make the convergence to the target vehicle speed constant regardless of the difference in gear speed, a method as shown in Japanese Patent Laid-Open No. 58-39312 has been proposed. In this publication, the operation amount of the throttle valve is determined by I-P control (control based on a formula having a forward integral term and a negative feedback proportional term), and the above integral term is determined according to the gear position. Alternatively, the control gain of the proportional term may be changed.

(Problem that the invention attempts to solve) However, this is not the case as described in the above-mentioned publication.

As the control gain is changed according to the gear position, the balance in the entire feedback control equation is likely to be lost. In other words, the control gain is set as an optimal value experimentally from various viewpoints, but if the control gain of the forward integral term is changed depending on the gear position, for example, the control gain of the negative feedback proportional term will change. It is more likely that a situation will arise where the relationship becomes unfavorable.

Of course, in order to prevent such a point of view, it is possible to change the control gains of all terms used in the feedback control equation depending on the gear position, but in this case, constant speed driving is performed. The experimental work to optimize all 7J control gains for all possible gears would be enormous, and the burden on the control system, especially memory capacity, would be heavy, and it would be difficult to change all the control gains. Therefore, new problems such as poor control responsiveness arise.

The present invention was made in consideration of the above circumstances, and
rFl! performs feedback control so that the actual vehicle speed becomes the target vehicle speed. However, we have developed a vehicle constant that can maintain constant convergence to the target vehicle speed regardless of the difference in gear speed by simply changing some control gains without disturbing the balance of the entire feedback control system. The object of the present invention is to provide a speed traveling control device.

(Means and operations for solving the problem) In order to achieve the above-mentioned object, in the present invention, for example, PI
-PD control or I-PD control is set to include at least a negative feedback proportional term, and the control gain in this negative feedback differential term is changed depending on the gear position. Specifically, as shown in FIG. 8, it includes a vehicle speed detection means for detecting the actual vehicle speed, an 11i speed adjustment means for adjusting the vehicle speed, and a system that receives the output from the vehicle speed detection means and generates at least a negative feedback differential term. a vehicle speed control means that performs feedback control so that the actual vehicle speed becomes a target vehicle speed by controlling the vehicle speed adjustment means with a control value obtained based on a predetermined formula; and a gear position that detects a gear position. The present invention is configured to include: a detection means; and a control gain changing means that receives an output from the gear position detection means and changes a control gain in the negative feedback differential term in accordance with the gear position.

Changing the control gain in the L2 negative feedback differential term will actually have an extremely large effect on changing the vehicle characteristics, especially on convergence, while changing the gear position is nothing but a change in this vehicle characteristic. The convergence to the target vehicle speed can be made constant regardless of the difference in gear position, with almost no influence on terms other than the above term.

(Example) Examples of the present invention will be described below based on the attached drawings.

In FIG. 1, reference numeral 1 indicates an automatic transmission, and reference numeral 2 indicates an automatic transmission, through which the output of the engine 1 is transmitted to drive wheels (not shown).

The automatic transmission 2 includes a torque converter 3 and a planetary gear type multi-stage transmission mechanism 4. This torque converter 3 includes a lock-up clutch (path shown), and turns the lock-up ON (engaged) and OFF (released) by switching between energization and demagnetization of the lock-up solenoid 5.
will be done. Further, the transmission mechanism 4 has four forward speeds in the embodiment, and a desired speed is achieved by changing the combination of excitation and demagnetization for the plurality of speed change solenoids 6, as is known. Of course, each of the solenoids 5 and 6 above switches the operating mode of the hydraulic actuator for lock-up or gear change, but since these are well-known matters, we will not explain them here. is omitted.

In FIG. 1, IO is a control unit constructed using a microcomputer, and signals from each sensor or switch 11 to 20 are input to this control unit. ”1 Sensor 1
1 detects the accelerator depression amount, that is, the accelerator opening degree. The sensor 12 detects the actual vehicle speed. The switch 13 is the driving range position of the automatic transmission; δ(
1, 2, D, P, R, N). The sensor 14 detects the current gear position of the automatic transmission 2, that is, the gear position. Switches 15 to 18 are operated by the driver for constant speed running, and as will be described later, 15 is a main switch, 16 is a set switch, 17 is a coast switch, and 18 is a resume switch. The switch 19 has speed change characteristics such as power mode (see Figure 3) and economy mode (see Figure 2).
This is for manually selecting one of the following. The switch 20 is a brake switch that is turned on when the brake is operated.

Further, the control unit 10 outputs an output to the throttle actuator 7 and each of the solenoids 5.6. This throttle actuator 7 drives a throttle valve 8 provided in the intake passage of the engine 1, and the control unit 10 normally controls the throttle valve according to the amount of accelerator depression based on the basic throttle characteristic line shown in FIG. The actuator 7 is controlled to achieve the opening degree. On the other hand, during constant speed driving control, the throttle opening degree is automatically controlled regardless of the accelerator opening degree, as will be described later.

Note that the control unit 10 basically consists of a CPU, ROM%
In addition to being equipped with RAM, CLOCK (Soft timer),
It has an A/D or D/A converter and a human output interface, but since these are known configurations when using a microcomputer, their explanation will be omitted.

Note that the speed change characteristics, throttle characteristics (map), etc. are stored in the ROM of the control unit 10.

- Of the controls by the control unit 10, the speed change control (lock-up control) and the throttle control based on the throttle characteristics shown in FIG. 4 are performed in the same manner as in the past. A detailed explanation will be omitted, and only the constant speed running control will be explained below.

First, the operation mode of the switch used for constant speed driving control is as follows. That is, the main switch 15 is 1
For example, it may be a button-button type, and the ON state or OFF state will continue unless operated. The set switch 16 is, for example, a pushbutton type, and is turned on only when a suppressing operation is performed, and automatically turns on when the pressing force is released.
The coast switch 17 and the resume switch 18 are, for example, a swing lever type, and their operation parts are shared, and they are normally biased to the neutral position, and in this neutral position, both switches are 1
7.18 are both turned OFF, and when it is swung in one direction, the coast switch 17 is turned on, and when it is swung in the other direction, the resume switch 18 is turned on.

Based on the above, the conditions for executing constant speed driving control are set as follows.

■The main switch 15 is turned on, ■The driving range of the automatic transmission is in the D-shin 9 position (a position that allows all gears from 1 to 4), and ■The actual vehicle speed is 40K. m/h or more;
■The set switch 16 must be turned on when all the conditions in E-notes ■ to ■ are satisfied.

Further, the target vehicle speed is set (changed) as follows.

(2) When the set switch 15 is turned ON and continues, the vehicle speed is increased while the set switch 15 is turned ON, and the actual vehicle speed or the target vehicle speed at the time the set switch 15 is turned OFF is set.

- When the coast switch 17 is turned on, the vehicle is decelerated while the coast switch 17 is turned on, and the actual vehicle speed at the time when the coast switch 16 is turned off is set as the target vehicle speed.

The constant speed cruise control is canceled when the brake is operated, that is, when the brake switch 2o is turned on. After the constant speed cruise control is canceled due to this brake operation, the resume switch 18 is turned on. Then, constant speed driving control is performed in which the target vehicle speed for the first shift where the brake is operated is set as the new target vehicle speed.

In the embodiment, feedback control in constant speed running control is performed by PI-PD sub-control as shown in FIG. More specifically, the operation of the throttle valve 8 during constant speed driving control! 11 (feedback correction amount) is calculated based on the following equation (l).

VTAG=KDX (ENVn-F, NVn-+)
+KI Amount of change) E N V n = Vo V nvo: Target vehicle speed vn: Actual vehicle speed KP: 1 for forward proportional constant: Forward integral constant K PV: Negative feedback proportional constant KDV: Negative feedback differential constant Note that the above formula (l) The middle suffix rn] means the current one in time, rn-IJ means one time before rnl, and In-24 means the second time before rnJ. .

In the above equation (l), KDV as the control gain of the negative feedback differential term is set (changed) depending on the gear position. For example, the control gain KDV for 4th gear is set as KDV4, and the control gain KDV for 3rd gear is set as KDV4. The control gain KDV for the second speed and the first speed is set as KDV2. Then, KDV2 > K DV3 > so that the response speed is slow in low gears.
K DV4 and the story. Note that the control gains for the first speed and the second speed may be set separately and independently.

TS'i Committee'-:II' E Flowch-Now then,
The details of the constant speed running control will be explained with reference to the flowcharts shown in FIGS. 6 and 7.

In this flowchart (Fig. 6), two flags F1 and [:2 are used, and flag F1 is NJ
When the vehicle is traveling at a constant speed, it means that the conditions for executing constant speed driving control are satisfied, and when the flag 1:2 is "1", it means that the brake was operated while the vehicle was traveling at a constant speed. Note that in the following explanation, P or Q indicates a step.

Based on the above, first initialization of the entire system is performed at pt in Fig. 6, then signals from the sensors or switches 11 to 20 are manually inputted at P2, and then shift control (lock-up control) is performed at P3. ) will be carried out.

[) After 3, if it is determined by the determination processing in P4 to P6 that the main switch I5 is ON, the D-shin 9 position, and the actual vehicle speed is 40 Km/h or more, then in the PI, It is determined whether or not the set switch 16 is ON. If PI's determination is YES, I)
After the flag l is set to rlJ in step 8, it is determined in step P9 whether or not the set switch 16 has been changed from ON to OL:F. If the determination in I)9 is No, the set switch 16 remains ON, so the PI
At point O, the opening degree of the throttle valve 8 is increased to increase speed based on a predetermined formula. Further, when the determination in P9 is YES, the actual vehicle speed at the time when the set switch 16 was turned OFF or the target vehicle speed is set in Pll. After this PLL, if the coast switch 17 is not operated or the brake is not operated,
PI2, P 16%I)! If all the determinations in step 7 are NO, the process moves to P22 and the ASC as shown in FIG. 7, which will be described later, is executed.
That is, constant speed driving control is performed based on the above equation ( ).

The above pH value is determined by turning on the coast switch 17 at PI2.
When the determination in (■) 12 is YES, the coast switch 17 is
It is determined whether or not the switch has been switched from ON to OFF. This PI3 judgment is N.

In this case, the coast switch 17 remains ON, so
During PI4, the opening degree of the throttle valve 8 is reduced to perform deceleration based on a predetermined formula while the engine is ON. If the determination in P13 is YES, PI5 is set and the actual vehicle speed at the time when the coast switch 7 is turned off is set as the target vehicle speed. After this PI5, if no brake operation is performed, both PlB and PI7 are determined as No, and the process moves to P22, where ASC control is performed.

After step 1) 15, it is determined at PI 6 whether the brake switch 20 is ON, that is, whether the brake has been operated. If the determination in PI6 is YES, the flag F2 is set to rlJ in P23, and then the process moves to P24, where throttle control is performed based on the throttle characteristics shown in Fig. 4 (cancellation of constant speed driving control). .

When the determination in P16 is NO, it is determined in PI7 whether or not there is one flag F2. This PI7
When the determination is YES, that is, when the brake is operated once during constant speed driving control, in PI8,
It is determined whether the resume switch 18 is ON or not. When the determination of PI8 is No, it means that the driver has not requested to return to constant speed driving control.
In this case, the process moves to 1)24, and 1 in the constant speed running control continues as it is.

If the determination in P18 above is YES, in PI9,
It is determined whether the vehicle speed is the actual vehicle speed or the vehicle speed immediately before the brake operation. If this PI9 judgment is No, P
At 2O, the throttle is controlled to increase speed based on a predetermined formula, and then the cycle returns to roundness PI9.

Then, if PI9 determines YES, P21
After the vehicle speed immediately before the brake operation (the vehicle speed that was set as the target vehicle speed in the iq constant speed driving control) is set as the target vehicle speed,
Moving to P22, constant speed driving control is performed.

On the other hand, if the determination in P7 is NO, it is determined in ))25 whether the flag Fl is 1 or not. This P2
If the determination in step 5 is YES, the processing from P12 onwards is performed. Also, the determination on P25 is N.

In this case, the driver does not request that constant speed driving control be executed, and in this case, after both flags Fl and F2 are reset to O (P26, P27), the state shown in FIG. Throttle control is performed based on the throttle characteristics shown.

Even when the determination in P4, P5, or P6 is NO, the conditions for constant speed driving control are not satisfied, so the processes from P26 onward are performed.

The ASC control at P22 described above is performed according to the flowchart shown in FIG. First, in Ql, it is determined whether the current gear stage is 4th gear or not. If the determination in Ql is YES, in Q3, the control gain KDV of the negative feedback differential term shown in equation (l) is set for 4th gear. Set as KDV4. In addition, when the determination of Ql is No, it is determined in Q2 whether the gear stage is 3rd gear or not, and this Q
If the determination in Q2 is YES, KDV is set to KDV3 for triple gear in Q4, and if the determination in Q2 is No, KDV is set to KDV2 for 1st speed and 2nd speed in Q5.

1. After Q3, Q4 or Q5, in Q6, (
l) After the operation amount VTAG of the throttle valve 8 is calculated based on the formula, this VTAG is output at Ql.

Although the embodiment E has been described above, in the feedback control for constant speed running control, any suitable control such as I-PD sub-control PI-D control may be adopted as long as it includes a negative feedback differential term. Further, in the case of a day cell engine, a member that adjusts the fuel injection amount may be used as the vehicle speed adjusting means.

(Effects of the Invention) As is clear from the above description, the present invention maintains constant convergence toward the target vehicle speed regardless of the difference in gear position,
This is preferable for constant speed running control.

In addition, since the control gain that is changed according to the gear stage is used exclusively for the negative feedback differential term that has a large effect on the convergence, it has an adverse effect on terms other than this negative feedback differential term. The convergence described above can be made constant without giving any difference. This also means that, for example, if various control gains are optimally set according to the highest gear where constant speed driving control is performed most frequently, the control gains for terms other than the negative feedback differential term may be changed for each gear. It is possible to obtain optimum constant speed running control without any trouble, and it is preferable in terms of minimizing the burden on the control system, especially the memory 8 sparrow, and further ensures responsiveness of the control. 1: is preferable.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. FIGS. 2 and 3 are characteristic diagrams showing speed change characteristics. FIG. 4 is a characteristic diagram showing throttle characteristics when constant speed running control is not performed. FIG. 5 is a block circuit diagram showing feedback control for constant speed running control. 6 and 7 are flowcharts showing control examples of the present invention. FIG. 8 is an overall configuration diagram of the present invention. l: Engine 2: Automatic transmission 7: Throttle actuator 8: Throttle valve lO: Control unit

Claims (1)

[Scope of Claims] (l) Vehicle speed detection means for detecting the actual vehicle speed, vehicle speed adjustment means for adjusting the vehicle speed, and a predetermined formula having at least a negative feedback differential term based on the output from the vehicle speed detection means. a vehicle speed control means that performs feedback control so that the actual vehicle speed becomes the target vehicle speed by controlling the vehicle speed adjustment means with a control value obtained based on the control value; a gear position detection means that detects a gear position; A constant speed running control device for a vehicle, comprising: control gain changing means for receiving an output from a detecting means and changing a control gain in the negative feedback differential term according to a gear position.