JP2003017318A - Current feedback type control method and apparatus of actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the current feedback type control method and apparatus of an actuator for making a current detection section single, and simplifying a configuration circuit in the driving control apparatus of the actuator that requires current feedback control. SOLUTION: A plurality of actuators 20A to 20C to be controlled are synchronized entirely for carrying out duty drive, the current value of a common current path 14 to each of drive circuits 12A to 12C of the actuators 20A to 20C is detected by a current detection circuit 13, a rate of current distribution to each drive circuit of the common drive current is calculated according to the drive duty signal value of each of the drive circuits 12a to 12C and the basic resistance value of each of the actuators 20A to 20C, the drive current value of each of the actuators 20a to 20C is estimated and calculated according to the current value detected by the current detection circuit 13 and the rate of current distribution to each of the drive circuits 12a to 12C of the calculated common drive current, and current feedback control is carried out for each of the actuators 20A to 20C by the drive current value of each actuator that has been estimated and calculated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current feedback type control method and apparatus used in an electronic control unit for an automobile and the like, and more particularly to a control method and method for individually controlling the driving of a plurality of actuators by a current feedback method. The present invention relates to a control device.

[0002]

2. Description of the Related Art A technique for controlling an actuator such as an electromagnetic solenoid or a heater by a current feedback system is disclosed in, for example, Japanese Patent Laid-Open Nos. 5-217737 and 7-194175.
No. 10-225179, and is often used for actuator control. In the conventional current feedback type control device, a pair of current detection circuits is provided for each drive circuit of each actuator, and the drive current of each actuator is individually detected by the current detection circuit of each actuator. .

[0003]

By the way, in the prior art, no consideration has been given to the increase in the scale of the circuit configuration of the current feedback type control device, and the current feedback control is required to meet the system specifications. Current detection circuits are required for the number of actuators to be used. Therefore, there is a problem that a large number of components are required and a large number of wirings corresponding to them are required. The present invention has been made by paying attention to the above-mentioned problems, and an object thereof is to provide a drive control device for an actuator which requires current feedback control,
An object of the present invention is to provide a current feedback control method and device for an actuator, which has a single current detection unit and realizes simplification of a constituent circuit.

[0004]

In order to achieve the above object, the current feedback control method according to the present invention includes a plurality of actuators having the same drive frequency as control targets, and the actuators are individually driven. In a control method of controlling by a current feedback method, all the actuators to be controlled are duty-driven in synchronization, and the current value of a common current path existing on the upstream side or the downstream side with respect to each drive circuit of the actuator is changed. Detected by the current detection means, the drive duty signal value of the drive circuit of each actuator, the current distribution ratio of the common drive current to each drive circuit is calculated from the basic resistance value of each actuator, and detected by the current detection means. From the current value and the current distribution ratio of the calculated common drive current to each drive circuit The one in which to calculate estimates the drive current value of each actuator, performs current feedback control for each actuator by using a drive current value of each actuator estimated calculated. According to this control method, it is possible to individually perform current feedback control on a plurality of actuators with a single current detection unit.

In drive control, the resistance value of the actuator to be driven changes with respect to the basic resistance value depending on the temperature condition. Therefore, the basic drive current value calculated using the basic resistance value of each actuator as a parameter is different from that in actual control. There is a possibility that a deviation occurs with respect to the drive current value of the driven actuator. Therefore, the drive duty signal of the actuator that is not the detection target is not changed, the drive duty signal of the actuator that is the detection target is independently changed by a predetermined amount, and the common drive current accompanying the change of the drive duty signal is changed. Calculate the resistance value of the detection target actuator in the actual control state from the change amount of the value,
The resistance values of all the actuators to be driven are calculated by the same method. The drive current distribution ratio to each drive circuit is corrected by the resistance values of all the actuators to be driven calculated by this method, and the current for each actuator is calculated while calculating the drive current value of each actuator distributed from the common drive current path. Perform feedback control.

Further, in the current feedback control method according to the present invention, when the drive signal to the target actuator to be detected is changed by a predetermined amount, the change amount of the common drive current value with respect to the change of the drive signal is When the value exceeds or falls below a predetermined range value, a failure such as a load short circuit and a load pseudo short circuit, a load disconnection and a load pseudo disconnection is detected.

In order to achieve the above object, the current feedback control device according to the present invention includes a plurality of actuators having the same drive frequency as control targets,
In a current feedback type control device for individually controlling the drive of the actuators by a current feedback system, current detection for detecting a current value of a common current path existing upstream or downstream with respect to each drive circuit of the actuators. Means, the current detection means all the actuators to be controlled synchronously duty drive,
The drive duty signal value of the drive circuit of each actuator, the current distribution ratio of the common drive current to each drive circuit was calculated from the basic resistance value of each actuator, and the current value detected by the current detection means was calculated. Control means for estimating and calculating the drive current value of each actuator from the current distribution ratio of the common drive current to each drive circuit, and performing current feedback control for each actuator using the estimated drive current value of each actuator. And have. According to this control device, it is possible to individually perform current feedback control on a plurality of actuators with a single current detection unit.

In the current feedback type control device according to the present invention, the control means further changes the drive signal to the one selected actuator to be detected by a predetermined amount, and responds to the change of the drive signal. The resistance variation value due to the temperature change of the actuator to be detected is calculated based on the variation amount of the common drive current value, and the resistance value calculation result of the target actuator is reflected in the distribution rate calculation from the common drive current to each drive circuit, The drive duty signal value of each actuator is corrected.

Further, in the current feedback control device according to the present invention, the common drive current value with respect to the change of the drive signal when the drive signal to the target actuator to be detected is changed by the control means by a predetermined amount. When the change amount of is larger or smaller than a predetermined range value, a failure such as load short circuit and load pseudo short circuit, load disconnection and load pseudo disconnection of the target actuator can be detected.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows one embodiment of a current feedback type control device according to the present invention. The current feedback controller is indicated generally by the numeral 10. The current feedback type control device 10 includes a microcomputer 11 which is a main part of the control device, a plurality of control target devices, and in this embodiment, drive circuits 12A and 12B of the three actuators 20A, 20B and 20C, respectively. , 12C and one current detection circuit 13.

The microcomputer 11 is composed of a microprocessor, an input / output interface device, a storage device, etc., and functions as an electronic control module (ECU). Hereinafter, the microcomputer 11 will be referred to as the ECU 1
Sometimes referred to as 1. The ECU 11 uses various sensors 21.
Input signals from outside the control device such as or switches 22
Based on the voltage value of the battery 30 that is a common power source of the actuators 20A, 20B, and 20C and the current detection value detected by the current detection circuit 13, each actuator 20A,
The optimum drive duty signals of 20B and 20C are individually calculated, and the drive circuits corresponding to the drive duty signals
12B and 12C are synchronously output.

The drive circuits 12A, 12B, 12C have a self-diagnosis function and an output short-circuit protection function, output load short-circuit and load disconnection failure states to the ECU 11, and output short-circuit protection when the load is short-circuited. While EC
All the actuators 20A, 20B, and 20C are duty-driven in synchronization with each other in accordance with the drive duty signal input from U11. Thereby, each actuator 20
A, 20B, and 20C are pseudo-current controlled. The actuators 20A, 20B, 20C referred to here are
Is an electric current controlled object such as an electromagnetic solenoid and a heater.

The current detection circuit 13 includes an actuator 20.
A, 20B, 20C individual drive circuits 12A, 12B,
The current value of the common drive current path 14 existing upstream of these drive circuits with respect to 12C, that is, the common drive current value (total current value) is detected. In response to this, the ECU
Reference numeral 11 is a drive duty signal value given to the drive circuits 12A, 12B, 12C of the actuators 20A, 20B, 20C, and each drive of a common drive current from the basic resistance value (parameter setting) unique to each actuator 20A, 20B, 20C. The current distribution ratio to the circuits 12A, 12B, and 12C is calculated, and the common drive current value detected by the current detection circuit 13 and the current distribution ratio of the calculated common drive current to each drive circuit are used to determine the actuators 20A and 20B. , 20C
The drive current value of is estimated and calculated individually. And ECU1
1 is each actuator 2 estimated and calculated as described above
Using the drive current values of 0A, 20B, and 20C, current feedback control is performed for each actuator 20A, 20B, and 20C, in other words, current feedback compensation is performed.

Next, the method of estimating the drive current of each drive circuit in the present invention will be described. Each actuator 20
The drive currents flowing through A, 20B, and 20C, the common drive current value detected by the current detection circuit 13, and the drive circuits 12
It is estimated by the current distribution ratio calculated from the driving conditions of A, 12B, and 12C and the load state.

In order to easily compare the current distribution ratios under the respective driving conditions of the respective driving circuits 12A, 12B, 12C,
Actuators 20A, 20B, 20C to be controlled
Are of the same drive frequency, and drive the actuators 20A, 20B, 20C in a synchronized manner, and under the condition of the same synchronized drive cycle, each drive circuit 12A,
The current distribution ratios of 12B and 12C are estimated and calculated. The current value It of the current flowing through the common drive current path 14 detected by the current detection circuit 13 is the actuator 20A, 20A.
It is the sum of the respective drive currents Ia, Ib, Ic flowing through B and 20C. The drive currents Ia, Ib, and Ic (hereinafter collectively referred to as drive current In) are supplied to the actuators 20A and 2A, respectively.
In the energized state where the drive duty of 0B and 20C is 100%, the current value becomes a value suppressed by the drive duty ratio Dn. Since the drive duty ratio Dn functions to suppress the actuator drive current in a direct current manner, it can be regarded as a coefficient correlated with the resistance value of each actuator 20A, 20B, 20C to be driven (controlled).

Actuators 20A, 2 to be driven
The resistance values of 0B and 20C change with respect to the basic resistance value specified at room temperature due to a change in the ambient temperature in the mounting environment of itself and thermal effects such as self-heating due to energization for driving. The amount of resistance change from the basic resistance value due to the thermal effect is different depending on the driving conditions of the actuators 20A, 20B, 20C.
Since it is different for each of B and 20C, the balance of resistance values between the drive circuits viewed from the common drive current path 14 is different from the balance of resistance values assumed for the basic resistance values of the actuators 20A, 20B, and 20C. Therefore, the resistance value from the basic resistance value of each actuator 20A, 20B, 20C in actual control is used as a parameter for calculating the current distribution ratio from the common drive current path 14 to each drive circuit 12A, 12B, 12C. It is necessary to calculate the change in the temperature and compensate for the temperature.

FIG. 2 shows an energized state in actuator drive control when calculating a resistance value change from the actuator basic resistance value Rn due to a temperature change. In FIG. 2, (A) shows the energization state of the actuator 20A, and (B) and (C) show the actuators 20B and 2 similarly.
The energized state of 0C is shown respectively.

In order to calculate the resistance change with respect to the temperature change, at a specific timing determined in advance, it is possible to detect the object to be detected with respect to the previous energization state of all the actuators to such an extent that the behavior of the system to be controlled does not change significantly. In this example, the drive duty is changed only for the actuator 20A, as shown by the code ΔDn. Variation value ΔIt of the current detection value at this time
Is the current value peculiar to the actuator in which the drive duty is changed as described above, and the changed duty value Δ
Dn, the fluctuation value ΔIt of the detected current value, and the battery voltage V
The resistance value Rrn of the actuator, which fluctuates due to a temperature change using B and, can be expressed by the following equation 1. Rrn = VB / (ΔIt · ΔDn) ... Equation 1

The resistance change rate CRn from the basic resistance value Rn of the actuator in the current temperature state is expressed by the following equations 2, 3
become that way. CRn = Rrn / Rn ... Equation 2 CRn = VB / (ΔIt · ΔDn · Rn)… Equation 3 The resistance change rate CRn from the basic resistance value Rn of all the actuators to be driven is calculated by the same method. Then, by this, the deviation of the current distribution ratio caused by the temperature change of each actuator is corrected.

Using the basic resistance value Rn of each actuator, each drive duty ratio Dn, and the resistance change rate CRn of each actuator with respect to temperature, the resistance value RDn regarded as a direct current in consideration of the drive duty of each drive circuit is It becomes like 4. RDn = (Rn (1 + CRn)) / Dn ... Equation 4 Using the resistance value RDn considered as a direct current in consideration of the drive duty of each drive circuit obtained by Equation 4, the current shunt ratio to each drive circuit Calculate IRn.

Using the circuit configuration diagram of FIG. 1, each drive circuit (1
2A, 12B, 12C) will be described. Each actuator 20A, 20B, 20
Letting RDa, RDb, and RDc be resistance values regarded as a direct current in consideration of the drive duty corresponding to C, the actuators 20A, 20B, 2
The current diversion ratios RIa, IRb, and RIc to 0C are expressed by the following equations 5 to 7 based on the general law of diversion. IRa = (RDb + RDc) / (RDa + RDb + RDc) ... Equation 5 IRb = (RDa + RDc) / (RDa + RDb + RDc) ... Equation 6 IRc = (RDa + RDb) / (RDa + RDb + RDc). Driving the actuators 20A to 20C by the current shunt ratios IRa to IRc from the common drive current path 14 to the actuators 20A to 20C and the current value It of the common drive current path 14 detected by the current detection circuit 13. The current In is calculated by the following equation 8, and the actuators 20A to 20C are current feedback controlled. In = It × IRn ... Equation 8

When a failure occurs in the drive circuit, the ECU 11 uses the information from the self-diagnosis function of each drive circuit 12A, 12B, 12C to determine the failed drive circuit as its own C.
The PU command is turned off, and the estimated drive current is also calculated by setting the resistance value RDn corresponding to the faulty circuit to 0, calculating the drive current of another normal drive circuit, and performing current feedback control. Further, it is possible to detect a load short circuit, a load pseudo short circuit and a load disconnection, and a failure state of the load pseudo disconnection by using a method of calculating a change in the resistance value from the actuator basic resistance value Rn due to a temperature change.

In the method of calculating the change in the resistance value of the actuator with respect to the change in temperature according to FIG. 2 described above,
From the expansion from Expression 1, the fluctuation value ΔIt of the current detection value peculiar to the detection target actuator is changed to the changed duty value ΔD.
n, the battery voltage VB, and the resistance value Rrn of the actuator that has changed depending on the temperature, can be expressed by the following equation 9. ΔIt = VB / (Rrn · ΔDn) ... Equation 9 The change range of the resistance value Rrn of the actuator changed by temperature is previously determined by experimental data and the like, and from the maximum value and the minimum value in the normal load state by Expression 9. The change range of the current fluctuation value ΔIt peculiar to the detection target actuator is defined.

The maximum value of the variation range of the current fluctuation value ΔIt is ΔI
With tmax and the minimum value being ΔItmin, the calculated current fluctuation value ΔIt peculiar to the detected actuator to be detected.
Is the load short-circuit or the load pseudo short-circuit, and the condition 11 is the load disconnection or the load pseudo-disconnection, the failure state of the drive circuit is diagnosed. ΔIt ≧ ΔItmax ... Equation 10 ΔIt ≦ ΔItmin ... Equation 11 In this failure diagnosis method, by monitoring the drive current described above,
It is possible to detect a load pseudo short circuit or a load pseudo wire disconnection that cannot be detected at the failure determination level of the diagnostic function of the drive circuit.

According to this embodiment, a plurality of actuators 20A, 20B, 2 are provided by the single current detection circuit 13.
It is possible to perform current feedback control of 0C and detect load short circuit and load pseudo short circuit, load disconnection and load pseudo disconnection of the actuator to be driven, and simplification of the configuration circuit becomes possible. As described above, one embodiment of the present invention has been described in detail, but the present invention is not limited to the above-mentioned embodiment, and is designed within a range not departing from the spirit of the invention described in the claims. Various changes can be made in.

For example, the installation location of the current detection circuit 13 is
The drive current is not limited to the common drive current path 14 on the upstream side of the drive circuits 12A, 12B, and 12C, and may be any location where the total current of the drive currents flowing in the actuators 20A, 20B, and 20C can be detected. As shown in other embodiments, each drive circuit 12A, 12B, 1
The current detection circuit 13 can be installed in the common drive current path 15 on the downstream side of 2C.

[0027]

As can be understood from the above description, according to the current feedback control method and apparatus of the present invention, a plurality of actuators are individually subjected to current feedback control by a single current detection circuit, and further fault diagnosis is performed. It is also possible to simplify the configuration circuit.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a current feedback control device of the present invention.

FIG. 2 is a time chart showing an energized state during a resistance value correcting operation of the current feedback control device according to the present invention.

FIG. 3 is a circuit configuration diagram showing another embodiment of the current feedback control device according to the present invention.

[Explanation of symbols]

10 Current feedback type controller 11 Microcomputer (ECU) 12A, 12B, 12C drive circuit 13 Current detection circuit 14, 15 Common drive current path 20A, 20B, 20C actuator 21 Various sensors 22 Switches 30 battery

Claims (6)

[Claims] 1. A control method in which there are a plurality of actuators having the same drive frequency as control targets, and the drive of each of the actuators is individually controlled by a current feedback method. Driving, detecting the current value of the common current path existing on the upstream side or the downstream side with respect to each drive circuit of the actuator by the current detection means, the drive duty signal value of the drive circuit of each actuator, each actuator Calculate the current distribution ratio of the common drive current to each drive circuit from the basic resistance value of, from the current value detected by the current detection unit, and the calculated current distribution ratio of the common drive current to each drive circuit,
A current feedback control method, wherein the drive current value of each actuator is estimated and calculated, and current feedback control is performed for each actuator using the estimated and calculated drive current value of each actuator. 2. A drive duty signal to a selected one of the actuators to be detected is changed by a predetermined predetermined amount, and the drive duty signal of the detected object is changed based on the change amount of the common drive current value with respect to the change of the drive duty signal. A feature is that a resistance variation value due to a temperature change of the actuator is calculated, the resistance value calculation result of the target actuator is reflected in a distribution rate calculation from the common drive current to each drive circuit, and the drive duty signal value of each actuator is corrected. The current feedback control method according to claim 1. 3. The change amount of the common drive current value with respect to the change of the drive duty signal when the drive duty signal to the target actuator to be detected is changed by a predetermined amount, with respect to a predetermined range value. 3. The current feedback control method according to claim 2, wherein when it exceeds or falls below the target actuator, a failure such as a load short circuit and a load pseudo short circuit, a load disconnection and a load pseudo disconnection is detected. 4. A current feedback control device in which there are a plurality of actuators having the same drive frequency as control targets, and the drive of the actuators is individually controlled by a current feedback system. Current detection means for detecting the current value of the common current path existing on the upstream side or the downstream side and all the actuators to be controlled by the current detection means are duty-driven in synchronization, and the drive duty of the drive circuit of each actuator is The current distribution ratio of the common drive current to each drive circuit is calculated from the signal value and the basic resistance value of each actuator, and the current value detected by the current detection unit and the calculated common drive current to each drive circuit are calculated. The drive current value of each actuator is estimated and calculated from the current distribution ratio of Current feedback type control device, characterized in that it and a control means for performing current feedback control for each actuator by using the driving current value for each actuator. 5. The control means changes a drive duty signal to a selected one of the actuators to be detected by a predetermined amount, and sets the change amount of the common drive current value with respect to the change of the drive duty signal. Based on this, the resistance variation value due to the temperature change of the actuator to be detected is calculated, and the resistance value calculation result of the target actuator is reflected in the distribution rate calculation from the common drive current to each drive circuit to correct the drive duty of each actuator. The current feedback control device according to claim 4, wherein 6. The control means sets a predetermined predetermined amount of change of the common drive current value with respect to a change of the drive duty signal when the drive duty signal to the target actuator to be detected is changed by a predetermined predetermined amount. The current feedback control device according to claim 5, wherein when the value exceeds or falls below the range value, a failure such as load short circuit and load pseudo short circuit, load disconnection and load pseudo disconnection of the target actuator is detected.