JPH0535261B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Field of Industrial Application>> The present invention is directed to a vehicle application in which the mechanical connection between an accelerator operator and a throttle valve is severed, and the throttle valve is remotely controlled via a servo system. This invention relates to an accelerator control device.

≪Prior Art and its Problems≫ Conventionally, a vehicle accelerator control device that disconnects the mechanical connection between the accelerator pedal and the throttle valve by wires or links and remotely controls the throttle valve via a servo system has been used. For example, Tokkosho
There is one that can be found in Publication No. 58-25853.

However, in the case of such a vehicle accelerator control device, the accelerator pedal must be moved in a step-like manner due to quantization errors caused by digitalization of servo control, and due to the upper limit of the gain of the amplifier system when using an analog system. A steady-state deviation may occur if the driver depresses or depresses the pedal.

Therefore, as shown in Figure 1, when the accelerator is operated rapidly in the order of close → open → close, the throttle valve should normally return to the fully closed state, but the control ends with the throttle valve slightly open, and the throttle valve opens only slightly. remains as a steady-state deviation, resulting in a high idle speed.

≪Object of the Invention≫ The object of the present invention is to solve the problem in a vehicle accelerator control device using this type of servo system, due to quantization error when digitalized or the upper limit of amplifier system gain when analogized. The purpose of this invention is to prevent a steady deviation from occurring between the throttle valve target value and the actual value, thereby preventing the idle speed from increasing.

<<Structure of the Invention>> In order to achieve the above object, the present invention is constructed as shown in the claim correspondence diagram of FIG. a target value generating means c for generating a throttle opening target value corresponding to the detected accelerator operation amount;
A zero operation amount state detection means d for detecting that the accelerator operator b is in a zero operation amount state; Throttle opening degree detection means e for detecting the actual opening degree of the throttle valve f; Throttle valve Throttle open state detection means for detecting whether f is fully closed or open; Throttle correction command generating means (h) for issuing a correction command necessary to match the actual throttle opening value with the actual throttle opening value; Throttle closing command generating means i that issues until valve f is fully closed; throttle valve f in accordance with the content of the given command;
a throttle drive means j for opening and closing the throttle; and when the zero operation amount state and the throttle open state are detected, the content of the command to be given to the throttle drive means j is sent to the throttle correction command generation means h; It is characterized by comprising a switching control means k for switching from the throttle closing command generating means i side to the throttle closing command generating means i side.

<<Description of Embodiment>> Next, FIG. 5 is a block diagram simultaneously showing the hardware configuration and software configuration of an embodiment of the present invention, in which the servo system is digitalized.

In the figure, an accelerator zero stroke switch 10 is comprised of a limit switch or the like that is turned on only when the amount of depression of the accelerator pedal is in a zero state.

The pedal potentiometer 11 is the accelerator pedal 12
The pedal potentiometer 11 is composed of a potentiometer that operates in conjunction with the pedal operation.
Outputs an analog voltage V ₁ corresponding to the amount of depression of the accelerator pedal.

The throttle fully open switch 13 is comprised of a limit switch or the like that is turned on only when the throttle valve 14 is fully closed.

Throttle potentiometer 15 is throttle valve 1
The throttle potentiometer 15 is composed of a potentiometer that operates in conjunction with the opening and closing of the throttle valve 15, and an analog voltage V ₂ corresponding to the opening degree of the throttle valve is output from the throttle potentiometer 15.
is output.

The throttle valve 14 is controlled to open and close by a step motor 17 driven by the output of a drive circuit 16.

The output V ₁ of the pedal potentiometer 11 and the output V ₂ of the throttle potentiometer 15 are the first
The data is taken into the microcomputer 18 of.

This first microcomputer 18 outputs a pedal stroke signal V ₁ and a throttle opening signal V _{2 .}
Based on this, arithmetic processing to be described later is executed, and finally a rotation direction command is given to the step motor 17.
The step number command and rotation period command are repeatedly sent to the second microcomputer 19 at a constant period _T0 as commands.

On the other hand, the second microcomputer 19
6801 is used as the CPU, and uses a known free run counter and output conveyor register to output each phase pulse train for driving the step motor 17 to the drive circuit 16 as a result of the arithmetic processing described later. In response to this pulse train, the step motor 17 is rotated one step at a time in a designated direction by the action of the drive circuit 16.

Next, each process executed by the first microcomputer 18 will be explained in detail.

First, the signals V ₁ and V ₂ output from the pedal potentiometer 11 and the throttle potentiometer 15 are
After being digitized via the A/D converter 20,
Normalization processing is performed in step (100).

In this normalization process, the output range of V ₁ and V ₂ is matched with the numerical string 0 to 255 set on the microcomputer side, thereby converting V ₁ and V ₂ into V ₁ R and V ₂ R, respectively. Convert.

Next, in step (101), a throttle opening target value V ₁ SET is determined based on the determined pedal stroke V ₁ R by a table search method and an interpolation calculation process.

That is, in the memory of the microcomputer, characteristics indicating the relationship between the pedal stroke V ₁ R and the throttle opening target value V ₁ SET are stored in advance in the form of a function table.
By subtracting by V ₁ R, the corresponding V ₁ SET is determined.

Next, in step (102), the determined throttle opening target value V ₁ SET and the throttle opening actual value detected via the throttle potentiometer V ₂ are combined.
Find the deviation VER from V ₂ R and proceed to the next step (103)
Then, the direction of the rotation command to be given to the step motor 17 is determined based on whether the value of VER is positive or negative, and at the same time, the rotation period PER, which will be described later, is set to a constant value PER _0.
Fixed to.

Next, in step (104), the output of the accelerator zero stroke switch 10 is read, it is determined that the accelerator pedal is at the zero stroke position, and if the accelerator pedal is not at the zero stroke position, the following steps (105) and (106) are executed. .

In step 105, based on the obtained absolute value |VER| of the throttle opening difference VER, the table search method and complementary calculation process are used to calculate the
Find the number of rotational steps STEP.

That is, in the memory of the microcomputer, characteristics indicating the relationship between |VER| and STEP are stored in the form of a function table, and STEP is determined using the determined |VER| as an argument.

Note that since |VER| and STEP are set to have a substantially proportional relationship, as the absolute value of the deviation VER increases, the number of steps STEP also increases.

This number of steps STEP is determined by the step motor 17.
This corresponds to the total number of rotational steps when rotating one step at a periodic PER interval, which will be described later.

In the following step (106), the rotation direction determined in step (103), the period PER ₀ required for the step motor to advance one step, and step (105)
The number of steps STEP determined in is sent to the second microcomputer 19 as a command.

On the other hand, if it is determined in step (104) that the accelerator pedal has zero stroke, then in step (107) it is determined whether or not the throttle is fully closed based on the output of the throttle fully closed switch 13. , if the throttle is determined to be open, the following steps (108), (109), (110)
are executed sequentially.

First, in step 108, the number of steps STEP is fixed to a constant value STEP ₀ , and then in step (109)
Now, the rotation command direction is determined to be the direction in which the throttle valve closes.

In the next step (110), the rotation period PER is determined based on the actual throttle opening value V ₂ R by the table search method and interpolation calculation process.

In other words, the characteristics indicating the relationship between V ₂ R and PER are stored in advance in the memory of the microcomputer in the form of a function table, and by referring to this function table with V ₂ R as an argument, ,
PER is required.

In addition, in this function table, PER is set to be approximately inversely proportional to V ₂ R,
Therefore, the larger the value of V ₂ R, the smaller the value of PER.

In other words, due to this characteristic, as described later,
The response speed of the servo system becomes faster as the throttle valve opening becomes larger.

Next, the number of steps STEP ₀ , the rotation direction and the rotation period PER determined in steps (108), (109), and (110) are sent as a command to the second microcomputer 19 in step (106). sent in the form of

Next, details of the processing executed by the second microcomputer 19 will be explained.

As mentioned above, the second microcomputer 1
9 is a CPU 6801, which is equipped with a free run counter and an output conveyor register as is well known.

The free run counter is composed of an incremental counter that is synchronized with an independent clock and counts up regardless of the software. Also, when the set value of the output conveyor register and the counted value of the free run counter match, the free run counter automatically The functional configuration is such that an interrupt is issued to the microcomputer.

First, when the rotation direction, number of steps, and rotation period are sent in the form of a command from the first microcomputer 18, the second microcomputer 19 receives them through a known handshake process and stores them in a predetermined memory. (step)
200, 201).

At this time, the step number STEP is stored as an initial value in a predetermined step number counter STEPC.

From now on, when an OCR interrupt occurs, the step (200)
→ (202) → (203), and bit pattern output processing is executed in step (204).

In the memory of the microcomputer, bit patterns of each phase pulse train corresponding to each rotation device of the step motor are stored in advance as a table, and in this bit pattern output processing, the rotation direction given from the first microcomputer 18 is Based on the information and the bit pattern at that point in time, a new bit pattern is determined by a table lookup method and sent to the drive circuit 16.

The drive circuit 16 rotates the step motor 4 by a predetermined angle based on the output pulse train of each phase. The bit pattern creation process, step motor drive process, etc. are well known in various ways, so their explanations will be omitted.

Next, in step (205), the counter value +PER of the free run counter at that time is reset in the startup conveyor register OCR, and -1 is subtracted from the step counter STEPC at the same time.

From then on, when the time specified by the rotation period PER arrives, an OCR interrupt occurs and the step (200) →
(202) → (203) → (204) → (205) are repeatedly executed, and each time a new bit pattern is sent to the drive circuit 16, the value of the step counter STEPC is subtracted by -1. The process is repeated until the value of STEPC becomes zero, the bit pattern output process is completed, and a new command from the first microcomputer 6 is awaited.

When the processes of the first and second microcomputers are executed as described above, as shown in FIGS. 6 and 7, within the command output period _T0 from the first microcomputer 18, STEP
The step motor 17 performs step rotation for the number of times.

If the digital servo arithmetic processing in the first microcomputer 18 is normal, the throttle valve will be fully closed almost simultaneously when the pedal stroke becomes zero, so as shown in FIG.
The value of the rotation period Tper ₀ remains fixed by the rotation period data PER ₀ , and only the number of steps STEP changes according to the throttle opening error |VER|, and the opening of the throttle valve 14 reaches the target opening. It will be controlled.

On the other hand, if a steady deviation occurs between the throttle opening target value and the actual value due to quantization errors in the digital servo processing system, the throttle valve will not be fully closed when the pedal stroke is zero. As shown in Figure 7, the number of steps STEP
remains fixed at STEP ₀ , and the rotation period
Only PER decreases in inverse proportion to the actual throttle opening value V ₂ R.

Therefore, the throttle valve is driven in the closing direction at a relatively high speed regardless of the value of the pedal stroke V ₁ R at that time, that is, the throttle valve 14 is forcibly closed.

In addition, at this time, the speed at which the throttle valve 14 closes becomes faster as the actual value of the throttle opening is larger, and slower as the actual value of the throttle opening is smaller, due to the processing in step (110). This causes sudden changes in the intake air amount to the engine, and does not cause sudden deceleration of the running vehicle.

<<Effects of the Invention>> As is clear from the description of the embodiments above, according to the present invention, in a vehicle accelerator control device in which the throttle valve is remotely controlled via this type of servo system, the servo system is It is possible to prevent the idle rotation speed from increasing due to steady-state deviation.

In addition, the throttle closing command generating means issues a closing command to the engine such that the speed at which the throttle valve closes is made faster as the actual throttle opening value is larger and slower as the actual throttle opening value is smaller until the throttle valve is fully closed. It does not cause a sudden change in the amount of intake air and cause a sudden deceleration of a running vehicle.

[Brief explanation of the drawing]

Fig. 1 is a timing chart explaining the problem to be solved by the present invention, Fig. 2 is a diagram corresponding to claims of the present invention,
FIG. 3 is a block diagram showing the hardware and software configuration of an embodiment to which the present invention is applied, and FIGS. 4 and 5 are time charts explaining the operation of the embodiment device shown in FIG. 3. . a...operation amount detection means, b...accelerator operator, c...target value generation means, d...operation amount zero state detection means, e...throttle opening detection means, f...
...Throttle valve, g...Throttle open state detection means, h...Throttle correction command generation means, i...
Throttle closing command generating means, j...Throttle driving means, k...Switching control means.

Claims (1)

[Scope of Claims] 1. Operation amount detection means for detecting the operation amount of the accelerator operation element; A characteristic indicating the relationship between the operation amount of the accelerator operation element and the throttle opening target value is set in advance. ,
Target value generation means for generating a throttle opening target value corresponding to the detected accelerator operation amount; Operation amount zero state detection means for detecting that the accelerator operator is in the operation amount zero state; Throttle Throttle opening detection means for detecting the actual opening of the valve; Throttle open state detection means for detecting whether the throttle valve is fully closed or open; Throttle opening given from the target value generating means. Throttle correction command generation means for issuing a correction command necessary to match the target value with the actual throttle opening value given by the throttle opening detection means; Throttle closing command generating means that issues a closing command that is faster and slower as it is smaller until the throttle valve is fully closed; Throttle driving means that opens and closes the throttle valve in accordance with the content of the given command; a switching control means for switching the content of the command to be given to the throttle drive means from the throttle correction command generation means side to the throttle close command generation means side when a zero amount state is detected and a throttle open state is detected; A vehicle accelerator control device comprising: