JPS5837707A - Position controller - Google Patents

Abstract

PURPOSE:To keep the accuracy of position control for a long time stably, by performing the position control taking a position detector output as a reference value in detecting the application of a power supply and moving a body to be position-controlled to a reference position. CONSTITUTION:A detection circuit 37 supplies a signal to a latch circuit 36 and a comparison circuit 34 for a prescribed time after the power supply of a controller 3 is applied. In this case, the comparison circuit 34 generates a signal to drive a solenoid valve 51 and not to drive a solenoid valve 52, external air is introduced to a diaphragm chamber 12 and a needle 11 is returned to the fully closed position. A latch circuit 36 stores an output value of an A/D converter 31 at the time when the needle 11 is fully closed. An addition circuit 33 adds a value stored in the latch circuit 36 to the result of operation of an operation circuit 32, i.e. the needle objective position to detemine the objective needle position and the output is applied to a comparison circuit 34. Further, the solenoids 51 and 52 can be controlled so that the needle position becomes the objective position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a position control device suitable for controlling the needle position of a variable orifice that controls the amount of exhaust gas recirculation in an internal combustion engine.

Position control devices are used in various fields, are common control devices, and come in various types.

FIG. 1 is a configuration diagram showing a BGR amount control device in which a conventional position control device is applied to needle position control of a variable orifice that controls the amount of exhaust gas recirculation (hereinafter abbreviated as EGR) in an internal combustion engine. In this figure, Si 1 is an EGR quantity control system comprising a needle 11 as a position controlled body, a diaphragm chamber 12, a control negative pressure input section 13, an inlet 14 for introducing exhaust gas, and an output port connected to an intake manifold. It is a variable orifice that controls the Reference numeral 2 denotes a position detector which converts and detects the position (mechanical position) of the needle 11 and the needle 11 above into an electrical signal, in this case a variable resistor whose movable terminal is provided to interlock with the needle 11. 3 is a position control device, which includes the variable resistor 2, the A/D voice transformer 31,
It includes an arithmetic circuit 32 for calculating a target position, an adder circuit 33, a comparator circuit 34, and a drive circuit 35. 4 is the standard,
A power supply line, 51 and 52 are electromagnetic valves, and 6 is a negative pressure source.

That is, in the above-mentioned device, the variable orifice l moves the needle 11 in proportion to the magnitude of the negative pressure in the diaphragm chamber 12.
Since the position of the needle 11 and the amount of EGR are in a proportional relationship, the magnitude of the negative pressure in the diaphragm chamber 12 is controlled to control the position of the needle 11.
The position of the needle 11 is such that the A/D conversion conversion differential voltage is applied to one end via the reference power line 4, and the other end is grounded. The variable resistor 2 converts it into a voltage signal, and the A/D
The signal is input to the converter 31. In this case, the relationship between the position of the needle 11 and the output voltage of the variable resistor 21 is a linear relationship as shown in FIG. The voltage is V in Figure 2.

The relationship between the position of the needle 11 and the position of the movable terminal of the variable resistor 2 is adjusted in advance so that

The A/D converter 31 converts the output voltage of the variable resistor 2 into a digital value and outputs it to the comparison circuit 34.

On the other hand, the calculation circuit 32 calculates the position of the needle 11 such that the optimum IGR amount can be obtained for each operating condition from the input parameters PO1P1, Ptomi, Ph, etc. Relative needle target position when the position of the needle 11 when the needle 11 is fully closed is set to zero)
is sent to the adder circuit 33. In this case, the above input parameters Po%p1,P.

When -Ph is an anadami pressure, the result of human/D conversion is input to the arithmetic circuit 32.

Further, this arithmetic circuit 32 is composed of, for example, a microcomputer.

The adder circuit 33 calculates a value R corresponding to the output voltage VoK of the variable resistor 2 when the needle 11 is fully closed as shown in FIG.

is the reference value (needle 11 reference position) and the arithmetic circuit 32
In addition to the output value of , that value is output to the comparator circuit 34 as the absolute target needle position (hereinafter referred to as target needle position) of the needle 11. This comparison circuit 34 is an addition circuit 33
The output value of the A/D converter 31 is compared with the output value of the A/D converter 31, and a control signal for the electromagnetic valves 51 and 52 is generated according to the difference between these two input signal values.

FIG. 3 is a diagram for explaining the operation of such a comparison circuit 34, and the horizontal axis represents the output value of the addition circuit 33 and the A/D converter 3.
In other words, it shows the difference between the target needle position and the actual needle position.

Further, the large shaded area indicates a range where the position of the needle 11 has not reached the target needle position, and in this large area, the comparison circuit 34 sends an output signal to the drive circuit 35 to operate the solenoid valve 5. Delivery and therefore solenoid valve 52
At this time, the solenoid valve 51 is not driven, and as a result, the negative pressure of the negative pressure source 6 is guided to the diameter chamber 12, and the needle 11 is controlled to be pulled up to the target needle position. Ru. The regions indicated by +D and -D indicate dead zones, and are regions in which it is determined that the position of the needle 11 coincides with the target needle position, and the solenoid valves 51 and 52 are not driven in these regions. Further, a shaded area B indicates a range in which the needle 110 position exceeds the target needle position, and in this area B, the comparator circuit 34 sends an output signal to the drive circuit 35 to operate the solenoid valve 51. , Solenoid valve! s1 is driven. At this time, the solenoid valve 52 is not driven and one of the solenoid valves 51 is open to the atmosphere, so the atmosphere is introduced into the diaphragm chamber 12, and the needle 11 is directed to the 1st S needle position. It is controlled to be lowered.

After the above 5K, A/D converter 31 and adder circuit 3
The position is controlled so that the differential force between the two input signal values falls within the dead zone (+D, -D), and the optimum EGR amount can be obtained.

However, in the conventional device 3 described above, the adding circuit 33 calculates W by using the value Re relative to the output voltage To of the variable resistor 2 when the needle 11 is fully closed as a reference value (needle 11 reference position).
However, since the output voltage Tof is obtained through pre-adjustment, it contains an adjustment error, and this adjustment error appears as a control error. In addition, the pre-adjusted reference position may change due to changes over time, etc., and the above output voltage vO may change, so the initial accuracy must be maintained for a long period of time! It was extremely difficult.

The present invention provides a positional antistatic device that solves the above-mentioned problems by storing the reference position of the controlled object when the device is powered on, and controls the position of the controlled object using the stored value as the reference value. The purpose is to

The present invention will be described in detail below with reference to FIG. FIG. 4 is a block diagram showing an example of a PIGR amount control device in which the position control device according to the present invention is applied to needle position control of a variable orifice that controls the BGR amount in an internal combustion engine. The same reference numerals indicate the same or equivalent parts.

Further, in the figure, 36 is a latch circuit that stores the output value of the A/D converter 31 immediately before the supply of the output signal from the power-on detection circuit stops, and 37 is a latch circuit that detects the power-on of the position control device 36. , is a power-on detection circuit that supplies an output signal to the comparator circuit 34 and the latch circuit 36 for a certain period of time from that point.

Next, the operation of the above-mentioned device will be explained. That is, as described above, the detection circuit 37 supplies an output signal to the latch circuit 36 and the comparison circuit 34 for a certain period of time from the time when the power is turned on to the control device 3. At this time, the comparison circuit 34 An output signal is generated to drive the solenoid valve 51 and not to drive the solenoid valve 52. Therefore, the solenoid valve 51 is opened to the atmosphere, and the atmosphere is introduced into the dial 7 and 5 chambers 12.
Needle, 1%/11 will surely return to the fully closed position. On the other hand, the latch circuit 36 detects the output value of the A/D converter 31 immediately before the supply of the output signal of the detection circuit 37 stops, that is, the output value of the A/D converter 31 when the needle 11 is in the fully closed position. be remembered.

The adder circuit 33 determines the target needle position by adding the calculation result of the calculation circuit 32, that is, the above-mentioned relative needle target position and the stored value of the latch circuit 36, and supplies the output signal to the comparison circuit 34, as follows. , solenoid valve 15 so that the position of needle 11 becomes a given target needle position.
1.52 is controlled and position control is performed in the same manner as in the case of FIG.

In the embodiment shown in FIG. 4, each circuit of the position control device 3 is constructed separately and independently by a digital circuit.
The parts other than 5 may be constituted by one device having an arithmetic function such as a microcomputer. In addition, FIG.
5 and the detection circuit 37 are constructed of a device having a time-series serial computing ability, such as a microcomputer, the reset circuit of the microcomputer can be used as the detection circuit 37. Further, the position-′-device 3 is not limited to being constructed only from a digital circuit.

Further, in the above embodiment, the reference position of the needle 1kll is set to the fully closed position of the needle 11, but the present invention is not limited to this. Further, a similar effect can be obtained by inputting the value obtained by subtracting the contents of the latch circuit 36 from the output signal of the A/D converter 31 and the output signal of the arithmetic circuit 32 to the comparator circuit 84.

Furthermore, in the above-mentioned embodiment, a case has been described in which the present invention device is applied to the position control of a variable orifice that controls the amount of EGR in an internal combustion engine, but it is not limited to this only, and It goes without saying that the device of the present invention can be applied to any position control system equipped with a position detector that converts the position of the object into an electrical signal.

As described above, according to the present invention, it is detected that the device power is turned on, and at that time, the position controlled object is moved to the reference position, the output value of the position detector at this time is stored, and the Since the position of the controlled object is controlled using the stored value as a reference value, there is no need to adjust the positional relationship between the controlled object and the position detector.Furthermore, since the positional relationship does not change over time, the position This has the effect of stably maintaining control accuracy for a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a BGR amount control device for an internal combustion engine to which a conventional device is applied, and Fig. 2 shows the relationship between the needle position and the output voltage of the variable resistor in Fig. 1.
, FIG. 3 is a diagram for explaining the operation of the comparison circuit in FIG. 1, and FIG. 4 is a diagram showing an FfGR in which the position control device according to the present invention is applied to needle position control of a variable orifice that controls the IGR amount of an internal combustion engine. FIG. 2 is a configuration diagram showing an example of a quantity control device. 1-variable oriice, 11-needle (position controlled body,
2--Variable resistor (position detector), 3-Position control device, 3
1-mu/D converter, 32-arithmetic circuit, 33-addition circuit,
34-. Comparison circuit, 35-. Drive circuit, 36-. Ratte circuit, 37-. Power-on detection circuit. In addition, the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 4

Claims (1)

[Claims] A position detector that converts and detects the mechanical position of the controlled object into an electrical signal, a power-on detection circuit that detects when the device power is turned on, and a power-on detection circuit that detects when the device power is turned on. , means for controlling the position controlled body to a reference position, and reference position storage means for storing an output signal level of the position detector when the position controlled body is controlled to the reference position by the control means. A position control device comprising: a position control device for controlling the position of the position-controlled body using the stored value of the storage means as a reference value.