JPH06149348A - Controller with abnormality diagnostic function - Google Patents

Abstract

PURPOSE:To provide a controller with an abnormality diagnostic function which diagnoses the abnormality of the controller only when an abnormality is generated at a CPU itself. CONSTITUTION:Two sensors SR and SL are respectively connected with interfaces 5A and 5B of two controllers A and B. Also, the controllers are connected through a communication channel C. A sensor output signal directly inputted to the controller is compared with the sensor output signal fectched through the communication channel and when a deviation more than a prescribed threshold value is generated at least two compared results, the abnormality of the controller is diagnosed. Therefore, the abnormality of the controller can be prevented from being erroneously diagnosed when the abnormality is generated at the sensor, and the reliability of the diagnostic result can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device with an abnormality diagnosing function, and more particularly to a control device with an abnormality diagnosing function capable of discriminating between an internal abnormality and an external abnormality.

[0002]

2. Description of the Related Art In recent years, microcomputer systems are often used in automobile control systems such as anti-skid brake systems, traction control systems, and four-wheel drive control systems. The high reliability is required for the microcomputer system used for the control system that executes such important control.
A so-called 2-CPU system that uses two central processing units (hereinafter referred to as CPUs) is generally used to determine that the control system is abnormal when a deviation of a predetermined threshold value or more occurs in the calculation results of the two CPUs. Target.

[0003]

However, in the above system, the control system may be determined to be abnormal even when an abnormality occurs in the sensor that transmits the input signals to the two CPUs. The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device with an abnormality diagnosis function that diagnoses that the control device is abnormal only when an abnormality occurs in the CPU itself.

[0004]

A control device with an abnormality diagnosing function according to the present invention comprises at least two detectors for detecting at least two kinds of state quantities, and a first detector to which at least two detectors are connected, respectively. And a second computer system, which is a control device with an abnormality diagnosis function, wherein each of the first and second computer systems processes at least a transmission signal transmitted from at least two detectors. One signal processing unit that outputs two pieces of processing information, and the processing information processed by the signal processing unit is transmitted to another computer system, and the processing information processed by the signal processing unit of another computer system is taken in as reference information. A first predetermined value is provided between the reference information exchange means and one piece of specific reference information corresponding to one piece of specific processing information in the processing information processed by the signal processing means. The second predetermined value is provided between the at least one processing information other than the specific processing information and the corresponding at least one reference information other than the specific reference information in the processing information processed by the signal processing means at the same time when the signal processing unit deviates from the relation. An abnormality diagnosing means for diagnosing that the computer system is abnormal when the relationship is deviated.

[0005]

When the predetermined relationship between the processing signals processed by the two CPUs corresponding to one state quantity is no longer established, at the same time, two CPs corresponding to at least one other state quantity.
The CPU is determined to be abnormal only when the predetermined relationship between the processed signals processed by U is not established.

[0006]

1 is a block diagram of an embodiment of a control device with an abnormality diagnosing function according to the present invention, showing an anti-skid brake system. A right front wheel rotation speed sensor (including a waveform processing circuit) SR and a left front wheel rotation speed sensor (including a waveform processing circuit) SL are installed as detectors, and are connected to two control devices A and B, respectively. ing.

The two controllers A and B are microcomputer systems and have the same structure. That is, each control device is centered on the bus 1, the CPU 2, the memory 3, the communication interface 4, the input interface 5, the output interface 6 and the alarm lamp 7.
Composed of.

In the following description, when it is necessary to distinguish the two control devices A and B, they will be referred to as 1A or 1B. The communication interfaces 4A and 4B of the two control devices A and B are connected by a communication line C. FIG. 2 is a flowchart of an abnormality diagnosis routine executed by each of the two control devices A and B, which are executed asynchronously as interrupt processing at regular time intervals.

The processing in the controller A will be described below.
In step 21, the rotation speed signal RRA detected by the right front wheel rotation speed sensor SR and the left front wheel rotation speed sensor SL
The rotation speed signal RLA detected by is read. The algorithm for this rotation speed reading process is commonly used by the two control devices A and B. That is, if the two control devices A and B perform the same processing on one rotation speed signal, and if the two control devices A and B are both normal, 2
The two processed signals coincide with each other within a predetermined range, but when an abnormality occurs in one of the two control devices A or B, a deviation occurs between the two processed signals.

In step 22, the rotation speed signals RRB and RLB read by the control device B are fetched into the control device A via the communication line C. In step 23,
Information RRA read by the control unit A about the number of rotations of the right front wheel and communication line C read by the control unit B
The deviation ΔRR from the information RRB taken into the control device A via the is calculated.

In step 24, the deviation ΔRL between the information RLA read and processed by the control device A and the information RLB read and processed by the control device B and taken into the control device A via the communication line C is calculated in step 24. Is calculated. In step 25, the absolute value of the deviation ΔRR is the first
Is greater than or equal to the threshold value ε1 of.

If an affirmative decision is made at step 25, then the processing advances to step 26, at which it is decided whether or not the absolute value of the deviation ΔRL is greater than or equal to a second threshold value ε2. Step two
If the affirmative determination is made in step 6, the process proceeds to step 27 and the alarm lamp 7A is output via the output interface 6A.
Is lit to indicate that an abnormality has occurred in the control device A, and this routine ends.

That is, when the two deviations exceed the threshold value at the same time, it is judged that the control device is abnormal, and, for example, an abnormality occurs in the right front wheel rotation speed sensor SR and the deviation ΔRR becomes the threshold value ε.
If the left front wheel rotation speed sensor SL is normal even if it exceeds 1, since the deviation ΔRL does not exceed the threshold value ε2, it is erroneously diagnosed that an abnormality has occurred in the control device A itself due to an abnormality in the right front wheel rotation speed sensor SR. Is prevented.

When a negative determination is made in step 25 or step 26, this routine is directly ended. It is also possible to add a temporal judgment element to one or both of the processes of step 25 or step 26.
For example, in step 25, an affirmative determination can be made when the state in which the absolute value of the deviation ΔRR is equal to or greater than the first threshold value ε1 continues for a predetermined time of, for example, 100 milliseconds.

By thus adding the time judgment element, the accuracy of the control device abnormality diagnosis can be improved. In the above-described embodiment, the case where the abnormality diagnosis is performed mainly by the right front wheel rotation speed signal and the left front wheel rotation speed signal is described, but it is clear that the abnormality diagnosis can be performed mainly by the left front wheel rotation speed signal. .

Further, the number of signals used as a subordinate is not limited to one, and may be two or more.

[0017]

According to the control device with an abnormality diagnosing function of the present invention, it is possible to distinguish the abnormality of the sensor from the abnormality of the control device, and it is possible to surely perform the abnormality diagnosis of the 2CPU system.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a flowchart of an abnormality diagnosis routine.

[Explanation of symbols]

 SR, SL ... Front wheel speed sensor 1A, 1B ... Bus 2A, 2B ... CPU 3A, 3B ... Memory 4A, 4B ... Communication interface 5A, 5B ... Input interface 6A, 6B ... Output interface 7A, 7B ... Alarm lamp C ... Communication Line

Claims (1)

[Claims] 1. An abnormality diagnosis function comprising at least two detectors for detecting at least two kinds of state quantities, and first and second computer systems to which at least two detectors are connected respectively. In the control device, each of the first and second computer systems includes one signal processing means for processing a transmission signal transmitted from at least two detectors and outputting at least two processing information; and a signal processing means. Of the processing information processed by the signal processing means, the reference information exchange means for transmitting the processed processing information to another computer system and taking in the processing information processed by the signal processing means of the other computer system as reference information. The first predetermined processing information and the corresponding one specific reference information deviated from the first predetermined relationship, and at the same time, processed by the signal processing means. Corresponding at least one non-specific references and at least one processing information other than the specific process information in the management information
A control device with an abnormality diagnosing function, comprising: an abnormality diagnosing means for diagnosing that the computer system is abnormal when a deviation from a second predetermined relationship between the two pieces of reference information.