JPH04235609A - Trouble detecting method for differential transducer - Google Patents

Abstract

PURPOSE:To detect the trouble of a differential transducer without using any exclusive circuit for detection of troubles by providing the processes to discriminates the change of the output of a demodulator, the change of the rotational direction command of a motor, and the change of the rotational angle of the motor respectively. CONSTITUTION:A 1st process is provided to discriminate whether the output signal of a demodulator 34 changed to the precedent output value or not together with a 2nd process where it is discriminate whether the revolving direction command of a motor 32 changed to the precedent input value or not, and a 3rd process where an angle signal is inputted from an angle sensor 38 and it is discriminated whether the rotational angle o the motor 32 changed or not. If the coil of a differential transducer 33 is opened or short-circuited, the output of the demodulator 34 is fixed at 0V or a constant level. Then a servo loop is opened and the motor 32 works in response to its revolving direction command. Thus the motor 32 changes and detects the trouble of the transducer 33.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a failure in a differential transducer, and more particularly to a method for detecting a failure in a differential transducer used for servo control of a motor-driven drive body.

0002

2. Description of the Related Art A block configuration of a conventional servo control device using a differential transducer is shown in FIG. 3, for example. In FIG. 3, a microcomputer 1 inputs a command signal, an angle signal from an angle sensor 2, and a position signal from a differential transducer 4 passed through a demodulator 5, and controls a motor 6 based on these input signals.
A predetermined drive signal is output to drive the control surface 9 of the aircraft, which is connected to the motor 6 via the reducer 7 and the reciprocating member 8 .

When detecting a failure of the differential transducer 4 as described above, that is, an open or short circuit in the primary coil or the secondary coil, when the differential transducer is in a normal state, the outputs of the two secondary coils are detected. Utilizing the fact that the sum of voltages is approximately constant, a failure detection method using a circuit as shown in FIG. 4 or 5, for example, is applied. Note that FIG. 4 is a circuit diagram when the A+B phase output necessary for failure detection is generated using the microcomputer 1 in FIG. 1, and FIG. 5 is a circuit diagram when the A+B phase output is generated without using the microcomputer 1. This is a circuit diagram for the case where the same configurations as those in FIGS. 4 and 5 are denoted by the same reference numerals, and redundant explanation will be omitted.

In FIG. 4, the A phase and B phase of the differential transducer 4 are input to operational amplifiers 11 and 12, and the -A phase output from the operational amplifier 11 and the +B phase output from the operational amplifier 12 are input to the operational amplifier 13.
is input to the inverting terminal of the rectifier circuit 14 as the A-B phase.
is output through. The output signal from this rectifier circuit 14 is the signal fed back to the microcomputer 1.

On the other hand, +B output from the operational amplifier 12
The phase is input to the inverting terminal of the operational amplifier 15, becomes the -B phase, and is output through the rectifier circuit 16. The output A-B phase of the rectifier circuit 14 and the output-B phase of the rectifier circuit 16 are connected to the A/D (Analog-Di) of the microcomputer 1 in FIG.
(A-B) + (-B) x (-2) = A + B, and A
It is determined whether or not the value of the +B phase falls within a predetermined range, and when the value is not within the predetermined range, it is determined that the differential transducer 4 has failed. Therefore, the circuit required only to detect a failure in the differential transducer is the failure detection circuit 17, which is comprised of the operational amplifier 15, the rectifier circuit 16, and the like. In addition, 18 is a differential transducer 8
This is an oscillator for exciting the primary coil, and also generates synchronization signals for rectifying each output signal.

In FIG. 5, the +B phase output from the operational amplifier 12 is input to the inverting terminal of the operational amplifier 21, and the −B phase output from the operational amplifier 21 and the operational amplifier 1 are input to the inverting terminal of the operational amplifier 21.
The −A phase output from the operational amplifier 22 is inputted to the inverting terminal of the operational amplifier 22, becomes the A+B phase, and is outputted through the rectifier circuit 23. 24 is A+ output from this rectifier circuit 23
This is an output discrimination circuit that detects a failure of the differential transducer 4 based on whether the value of the B phase falls within a predetermined range. Therefore, the circuit necessary only for detecting a failure of the differential transducer 4 is the failure detection circuit 25, which includes the operational amplifier 21, the operational amplifier 22, the rectifier circuit 23, the output discrimination circuit 24, and the like.

[0007]

[Problems to be Solved by the Invention] However, in these conventional differential transducer failure detection methods, special failure detection circuits 17 and 25 are required in addition to the circuits necessary for servo control, so that hardware There was a problem that the wear size became large. In particular, when a single controller manages a large number of differential transducers, the hardware size becomes even larger.

Accordingly, the present invention provides a step of determining a change in the output of a demodulator that inputs a signal from a differential transducer, a step of determining a change in a motor rotation direction command, and a step of determining a change in the rotation angle of the motor. The objective is to reduce the hardware size by making it possible to detect failures in differential transducers without providing a dedicated circuit for failure detection.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the present invention is used for servo control of a driving body driven by a motor based on an input command, detects the position of the driving body, and transmits position information to a demodulator. A method for detecting a failure in a differential transducer that is fed back through a motor, the first step being detecting the output of a demodulator and determining a change in the output, and detecting a motor rotation direction command and determining a change in the command. The present invention is characterized in that it includes a second step of detecting the rotation angle of the motor and a third step of detecting a change in the rotation angle.

[0010] Furthermore, the first step, the second step, and the third step may be repeated a plurality of times, and the differential transducer may be determined to be faulty when it is determined that the differential transducer is faulty a plurality of times in succession.

[0011]

[Operation] In the present invention, when the coil of the differential transducer is open or shorted, the output of the demodulator becomes 0vo.
lt or a constant value, the servo loop is in an open state, the motor operates according to the motor rotation direction command, and the rotation angle of the motor changes, thereby detecting a failure of the differential transducer. therefore,
The differential transducer can be detected by determining changes in the output of the demodulator in the first step, determining changes in the rotational direction command in the second step, and determining changes in the motor rotation angle in the third step without providing a circuit dedicated to failure detection. failure detection becomes possible.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings. FIG. 1 is a diagram showing an embodiment of a servo control device to which a differential transducer failure detection method according to the present invention is applied,
FIG. 2 is a flowchart showing an example of the detection procedure of the differential transducer failure detection method according to the present invention.

First, the configuration of the servo control system shown in FIG. 1 will be explained. In FIG. 1, 30 is a servo-controlled driving body, and the driving body 30 is driven by a motor 32 via a gear 31. The driver 31 is connected to, for example, a control surface of an aircraft (not shown), and the control surface is driven in conjunction with the driver. The position of the driving body 30 is detected by a differential transducer 33, and the differential transducer 33 includes a primary coil and a secondary coil. The position signal from the differential transducer 33 is input to a summing point 35 through a demodulator 34;
A command signal for driving the driving body 30 to a predetermined position is input to. The output of the summing point 35 is inputted to the summing point 37 through the amplifier 36, and the angle signal from the angle sensor 38 is converted into a speed by the speed conversion logic 42 and inputted to the summing point 37. On the other hand, addition point 3
Motor rotation direction determination logic 43 based on the positive or negative output of 7.
determines the rotation direction of the motor 32 and sends its output to the driver 4
1 and the failure determination logic 44. Angle sensor 38 detects the rotation angle of motor 32 and outputs an angle signal corresponding to the detected rotation angle. The output of summing point 37 is passed through a pulse width modulation (PWM) circuit 40 to a driver 41.
The driver 41 rotates the motor 32 by a predetermined angle in a predetermined direction.

45 is a microcomputer, as shown in FIG.
In the example, the microcomputer 45 includes a servo calculation section and a PWM section, but it is also possible to configure some functions such as the PWM section outside the microcomputer 45. That is, the differential transducer 33 described above is used for servo control of the drive body 30 driven by the motor 32 based on input commands, detects the position of the drive body 30, and feeds back position information through the demodulator 34. . The output signal of the demodulator 34, the rotation direction command for instructing the rotation direction of the motor 32, and the angle signal of the angle sensor 38 are as follows.
The signals are input to the microcomputer 45, and the microcomputer 45 detects a failure of the differential transducer 33 based on these signals according to a procedure described later.

Next, the procedure for detecting a failure in the differential transducer 33 by the microcomputer 45 will be explained with reference to the flowchart shown in FIG. Note that S1 to S8 in FIG. 2 indicate each step of the flowchart. In S1, the output signal of the demodulator 34 is input, and in S2, it is determined whether the output signal of the demodulator 34 has changed from the previous output value,
If there is no change, proceed to S3. In S3, a rotation direction command for the motor 32 is input, and in S4, it is determined whether or not the rotation direction command has changed from the previous input value, and if it has not changed, the process advances to S5. In S5, the angle signal from the angle sensor 38 is input, and in S6
Then, it is determined whether or not the rotation angle of the motor 32 has changed, and if it has changed, the process advances to S7. In S7, a failure determination of the differential transducer 33 of the motor 32 is made. On the other hand, when it is determined in S2 that the output signal of the demodulator 34 is changing,
When it is determined in S4 that the rotation direction command signal is changing, and when it is determined in S6 that the rotation angle of the motor 32 is not changing, the process advances to S8 in either case. In S8, it is determined that the differential transducer 33 is normal. Note that S1 and S2 described above correspond to the first step of detecting the output of the demodulator 34 and determining a change in the output, and S3 and S4
corresponds to a second step of detecting a rotational direction command of the motor 32 and determining a change in the command, and S5 and S6 correspond to a third step of detecting a rotational angle of the motor 32 and determining a change in the rotational angle. This corresponds to the process of

On the other hand, the reason why a failure of a differential transducer can be detected by the procedure described above is as follows. That is, when the primary coil or the secondary coil of the differential transducer 33 is opened or shorted, the output signal of the demodulator 34 is fixed to 0 volts or fixed to a constant value by the offset voltage of the circuit. Also, at this time, the servo loop is in an open loop state, the motor 32 operates only in accordance with the input command signal, and the angle signal of the angle sensor 38 changes. Therefore, when the output signal of the demodulator 34 does not change, the rotational direction command of the motor 32 is the same, and the angle signal from the angle sensor 38 changes, the differential transducer 33
This is because it can be concluded that this is a failure.

As described above, in this embodiment, there are a step of determining a change in the output of the demodulator 34, a step of determining a change in the rotation direction command of the motor 32, and a step of determining a change in the rotation angle of the motor 32. has been established. Therefore, by processing these discrimination steps with a microcomputer, the output signal of the motor 32 can be detected without changing the output signal of the demodulator 34 using existing hardware without providing a circuit dedicated to failure detection such as an operational amplifier. When the rotation direction command is the same and the angle signal from the angle sensor 38 is changing,
That is, when the differential transducer 33 fails,
can be detected. Therefore, compared to conventional methods, the hardware size can be reduced. In particular, great effects can be obtained when a large number of differential transducers are provided.

In the example of the fault detection procedure described above, the differential transducer is determined to be faulty in one step shown in S1 to S8 in FIG.
The steps S1 to S8 may be repeated a plurality of times, and the differential transducer may be determined to be in failure for the first time when it is determined that the differential transducer is out of order a plurality of times in succession. In this case, erroneous detection due to noise voltage or the like can be completely prevented, and the reliability of failure detection can be further improved.

[0019]

According to the present invention, the first, second and third
This process enables the detection of differential transducer failures using existing hardware, that is, only the hardware required for servo control, without the need for a dedicated circuit for detecting differential transducer failures. It is possible to reduce the hardware size.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a servo control device to which a differential transducer failure detection method according to the present invention is applied.

FIG. 2 is a flowchart showing an example of a detection procedure of a differential transducer failure detection method according to the present invention.

FIG. 3 is a block diagram of a servo control device for explaining a conventional technique.

FIG. 4 is a diagram showing a failure detection circuit of the differential transducer in FIG. 3;

FIG. 5 is a diagram showing another failure detection circuit for the differential transducer in FIG. 3; 30 Drive body 32 Motor 33 Differential transducer 34 Demodulator 38 Angle sensor 45 Microcomputer

Claims (2)

[Claims] 1. A failure detection method for a differential transducer used for servo control of a driving body driven by a motor based on an input command, detecting the position of the driving body and feeding back position information through a demodulator, the method comprising: a first step of detecting the output of the motor and determining a change in the output; a second step of detecting a rotation direction command of the motor and determining a change in the command; and a second step of detecting the rotation angle of the motor and determining the change in the command. A method for detecting a failure in a differential transducer, the method comprising: a third step of determining a change in rotation angle. 2. The differential transducer is determined to be in failure when the first step, the second step, and the third step are repeated a plurality of times and the differential transducer is determined to be in failure a plurality of times in succession. A method for detecting failure of a differential transducer according to item 1.