JP2000231401A - Device for detecting abnormality of actuator driving - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the accurate operation of an actuator only by checking input and output signals from a central control unit to a driving circuit. SOLUTION: This device is provided with a detecting means for detecting abnormality based on the state of a control signal (a) outputted from a central control unit 1 to a driving circuit and the state of a signal (e) inputted through the driving circuit to the central control unit 1. The state of the control signal (a) outputted from the central controller 1 to the driving circuit is compared with the sate of the signal (e) inputted from the driving circuit to the central control unit 1 so that the abnormality of an element or load in the actuator driving circuit can be detected. That is, the normality or abnormality of the actuator driving can be accurately detected only by operating the signal processing of the input and output signals (a) and (e) from the central control unit 1 to the driving circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output signal and an input signal to a drive circuit from a central control device when an actuator is driven by a command from a central control device, such as when fabric is manufactured using a dobby machine. The present invention relates to an apparatus for detecting an abnormality of an actuator or an element of a drive circuit of the actuator by using the apparatus.

[0002]

2. Description of the Related Art In a loom, a plurality of heald frames are selectively raised or lowered to open a weft according to the pattern structure of a woven fabric, thereby obtaining a desired woven pattern. The raising or lowering of the heald frame is performed by selectively swinging a jack lever of a dobby machine connected to a wire provided on the heald frame. When the jack lever is swung, the hook in the jack lever swing mechanism is hooked and unhooked, and the operation transmission between the jack lever swing drive source (fluid cylinder as an actuator in the present invention) and the jack lever is turned on and off. It is done by that. The on / off control of the operation transmission between the fluid cylinder and the jack lever is performed by controlling ON / OFF of an electromagnetic valve for controlling the supply of the pressure fluid to the fluid cylinder.

[0003] Since the Dobby machine is a continuous operation that repeats raising and lowering the heald frame more than 600 times per minute on average, the occurrence rate of malfunctions must be kept extremely low. For this purpose, for example, JP-A-8-1
There is a technique disclosed in Japanese Patent Application Laid-Open No. 09537. In the technology described in this publication, a sensor is provided at a position where the jack lever swings and pulls the wire of the heald frame, and a signal from this sensor and an electromagnetic signal of the fluid cylinder output from a computer are provided. By comparing the signal with a pattern signal for operating the valve, it is determined whether or not the jack lever is operating normally to prevent malfunction.

[0004]

However, according to the technique described in the above publication, it is difficult to accurately detect the movement of the swinging portion of the jack lever by a sensor due to the vibration caused by the high-speed operation. Therefore, if there is any failure in the control circuit or the like of the fluid cylinder as the jack lever driving actuator, the jack lever may malfunction and the fabric may be defective. The causes of such actuator control system failures include failure in the short-circuit mode or open mode of the solenoid valve, poor contact or disconnection (dropout) of the connector connecting the solenoid valve and the drive circuit, and breakage of elements in the drive circuit. (Short or open), breakage of the drive circuit driving means (output port etc.), malfunction of the drive circuit driving means, and the like.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems and has been improved and eliminated. The present invention relates to a signal output from a central control unit to a drive circuit and a central control unit via the drive circuit. This is intended to prevent malfunction of the actuator by comparing with a signal inputted to the actuator.

According to the first aspect of the present invention, there is provided a method for controlling a state of an output signal from a central control unit to a drive circuit and an input signal to the central control unit via the drive circuit. An abnormality detection device driven by an actuator, further comprising detection means for detecting an abnormality based on a state of a signal to be transmitted. By comparing the state of the signal output from the central control device with the state of the signal input thereto, it is possible to detect an abnormality of an element or a load in the actuator drive circuit. Therefore, it is possible to accurately detect the normal / abnormal operation of the actuator simply by performing signal processing of input / output signals from the central control device to the drive circuit.

According to a second aspect of the present invention, the abnormality detecting means stores a state of an output signal from the central control unit to the drive circuit at a specific time, and drives at a time corresponding to the specific time. The actuator drive abnormality detection device according to claim 1, wherein a normal or abnormality is determined based on a combination of a state of a signal input from a circuit to a central control device and a state of the stored output signal. By comparing and judging the state of the input / output signal at a specific point in time, it is possible for the central control unit to determine whether it is normal or abnormal at a specific point in time.

Further, according to a third aspect of the present invention, the driving circuit includes an input section for receiving a signal from an output port of the central control unit, and a load on / off circuit in response to the operation of the input section.
A drive unit that switches OFF, an output unit that outputs a signal to an input port of the central control unit, a voltage-dependent element that operates according to the potential at an intermediate point between the drive unit and the load, a voltage-dependent element, and an output unit. 3. The abnormality detection device for driving an actuator according to claim 2, further comprising: a switch element that is provided between the first and second elements and that is turned on / off in accordance with an operation state of the voltage-dependent element. As described above, the voltage-dependent element that operates according to the potential at the intermediate point between the drive unit and the load, and the ON / OF that is provided between the voltage-dependent element and the output unit according to the operation of the voltage-dependent element
Since the switch element is provided with the F element, when the load fails in the short-circuit mode or when the load fails in the open mode, the potential state at the intermediate point can be accurately transmitted to the output unit via the switch element. it can.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the embodiments of the invention shown in the drawings. In the present embodiment, abnormality detection of actuator drive in a dobby machine having a jack lever for pulling a wire connected to a heald frame of a loom and an actuator for swinging a leading lever in the jack lever swing mechanism is provided. The device will be described. Such a dobby machine performs a continuous operation that repeats raising and lowering the heald frame at an average of 600 times or more per minute, for example. A large vibration is generated, and the operation signal of the actuator is frequently turned on and off in a short cycle. Abnormal detection of actuator drive is particularly important. In the present embodiment, the load driven by the drive circuit is an electromagnetic valve, and the actuator is a fluid cylinder controlled by the electromagnetic valve. However, the load such as a solenoid, which itself is an actuator, is driven by the drive circuit. You may do so. 1 and 2 show an embodiment of the present invention in which the actuator is a fluid cylinder for driving a jack lever of a dobby machine, FIG. 1 is a control circuit diagram, and FIG. 2 is a block diagram of the control circuit. .

As shown in FIG. 2, the control circuit for driving the jack lever has a drive circuit 2 which is controlled by an output signal from a central control circuit 1, and the drive circuit 2 controls the fluid cylinder for driving the jack lever. An electromagnetic valve (load) 3 for controlling the actuator is controlled to be turned on and off. Then, the drive circuit 2 determines the state of the electromagnetic valve 3 by the central control device 1.
Feedback. In the figure, reference numeral 4 denotes an output port for outputting an operation signal from the central control device 1 to the driver 2, and reference numeral 5 denotes an input port for inputting a status signal from the driver 2 to the central control device 1. The central control unit 1 is connected with a ROM program 6 for driving and controlling the loom, a RAM 7 for inputting fabric pattern data, a memory card 8 and a floppy 9.

FIG. 1 shows an electric circuit for exchanging data between the central control device 1 and the drive circuit 2. As shown in the figure, the control signal a output from the central control device 1 is input to the drive circuit 2 through the output port 4. Here, the operating voltage of the central control device 1 is +5 V, which is different from the operating voltage of the drive circuit 2 +24 V. Therefore, the control signal a input to the drive circuit 2 through the output port 4 is a light emitting diode (light emitter) 10 a
And an input-side photocoupler (input unit) 10 including a phototransistor (photoreceiver) 10b. The emitter side (point b in FIG. 1) of the phototransistor 10b is connected to the two-stage amplifying transistors Q1, Q
2 is connected to the base side of Q1. An electromagnetic valve 3 for controlling a fluid cylinder for driving a jack lever is connected to the collector side of the two-stage amplifying transistors Q1 _and Q2, and a diode 11 for protection is connected to the electromagnetic valve 3 in parallel. It is connected.

On the emitter side of the output transistor Q2, when an overcurrent is detected and an overcurrent flows, the transistor operates instantaneously to reduce the base current of the transistor Q2 and prevent the transistor Q2 from being damaged. Transistor Q
3 is connected to the base side and the resistor R3 side. The emitter side of the transistor Q3 is grounded, and the collector side is connected to an intermediate point connecting the emitter side of the phototransistor 10b and the base side of the transistor Q1. Further, the collector sides (point c in FIG. 1) of the output transistors Q1 and Q2 are turned on according to the voltage between the terminals.
A zener diode 12 which is a voltage-dependent element to be turned off
And a resistor R1, R2 connected in series to ground, and a zener diode 12 is provided at an intermediate point between the resistors R1 and R2.
The base of a transistor Q4 for failure detection which is turned ON / OFF in accordance with ON / OFF of the transistor is connected. That is,
The potential at point c rises above a predetermined level, and the Zener diode 12
When a voltage equal to or more than a predetermined voltage is generated between the terminals, a current flows through the zener diode 12, and accordingly, the transistor Q4 is turned on. The collector side (point d in FIG. 1) of the transistor Q4 is connected to the + side through the light emitting diode 13a of the output side photocoupler (output section) 13.
It is connected to the 24V power supply side. A power supply voltage of +5 V is applied to the collector side of the phototransistor 13b, which is the light receiving side of the photocoupler 13, and the collector side is further connected to the central controller 1 via the input port 5.

Next, the operation of the abnormality detecting device thus configured will be described. First, a case where the electromagnetic valve 3 for controlling the fluid cylinder for driving the jack lever of the dobby machine is operating normally will be described. In this case, as shown in FIG. 1, while the chip select signal Csn (valid signal) of the output port 4 is valid, the central controller 1
Outputs a control signal a for turning on the electromagnetic valve 3 based on the data of the weave pattern. That is, the signal on the data bus of the central controller 1 is the chip select signal C
It is taken into the output port 4 based on sn. The control signal a is sequentially turned ON / OF based on the data of the weave pattern.
Switching of F is performed.

The ON operation of the control signal a is transmitted from the light emitting diode 10a of the photocoupler 10 to the phototransistor 10b on the light receiving side, and the phototransistor 10b is turned ON. This phototransistor 10
The ON operation of b is latched by the output port 4 until the next control signal a (Hi) is input. Therefore, the output signal (b
The point signal) is maintained at the Vc voltage for a predetermined period. Therefore, this Vc voltage is applied to the base side of the output transistor Q1, and the transistor Q1 is turned on. As a result, the two-stage amplifying transistor Q2 is also turned on, and a current flows from the collector side to the emitter side of Q2. Therefore, a current also flows through the electromagnetic valve 3 to perform an ON operation. This electromagnetic valve 3
, The fluid is supplied to the fluid cylinder, the fluid cylinder protrudes, and controls the jack lever via a known swing mechanism.

When the two-stage amplifying transistors Q1 and Q2 (driving units for switching ON / OFF of the electromagnetic valve 3) are in an ON state, the voltage level at a connection point c, which is an intermediate point between the driving unit and the electromagnetic valve 3, is: It is "Low", no current flows through the zener diode 12, and the transistor Q4 connected to the connection point c via the zener diode 12 remains OFF output. Therefore, the voltage level at the connection point d is “H”.
i ", and the light emitting diode 13a directly connected to the connection point d remains OFF. At this time, since the light emitting diode 13a is OFF, the phototransistor 13b, which is its light receiver, also remains OFF, and The signal e input to the central controller 1 through the port 5 is inverted at the input port 5 to be a “Low” output, and thus the output signal a from the central controller 1 is “Hi”.
When the output is such that the input signal e corresponding to that state is a “Low” output, it can be considered that the drive circuit 2 and the electromagnetic valve 3 are normal.

On the other hand, when the control signal a from the central control unit 1 is "Low", the photocoupler 10 is turned off, no current flows to the base side of the amplification transistor Q1, and the transistors Q1 and Q2 It turns off.
Therefore, no current flows through the electromagnetic valve 3 and the valve is turned off, and the fluid cylinder does not perform the projecting operation (retreat).
At this time, since the voltage level at the connection point c becomes “Hi”, a current flows through the zener diode 12, the transistor Q4 and the photocoupler 13 are turned on, and the signal e input to the central control device 1 , And becomes a “Hi” output. Thus, the central controller 1
The drive circuit 2 and the electromagnetic valve 3 can also be considered to be normal when the control signal a output from the controller is "Low" output and the input signal e corresponding to that state is "Hi" output.

Next, a case where the transistor Q2 causes a short circuit to the power supply or a case where the electromagnetic valve 3 fails in the short circuit mode will be described. Even if such a short circuit accident occurs,
When the control signal a from the central controller 1 is “Low”,
The potential at the point c becomes “Hi”, and the input signal e to the central control device 1 becomes the same as in the normal state. However, when the control signal “a” becomes “Hi”, an excessive short-circuit current instantaneously flows from the collector to the emitter of the transistor Q2. If the short-circuit current continues for several seconds, the transistor Q2 will be broken due to the allowable power of the transistor Q2.

Therefore, in the circuit of FIG. 1, a short-circuit protection circuit (current limiting circuit) including the transistor Q3 and the resistor R3 is provided in order to prevent this. In this circuit, a predetermined voltage defined by the resistance value of the resistor R3 and the current value flowing through it is applied to the base side of the transistor Q3. As described above, when a short-circuit current larger than normal flows from the collector of the transistor Q2 to the emitter side, the voltage across the resistor R3, that is, the transistor Q2
3, the base voltage increases, and the transistor Q3 is turned on.
Operate. Therefore, the base current of the transistor Q1 (collector current of the phototransistor 10b) is bypassed as the collector current of the transistor Q3, and the base voltage applied to the transistor Q1 is reduced. As a result, the base current and the collector current flowing through the transistor Q1 decrease, and subsequently, the collector current of the transistor Q2 also decreases, thereby protecting the transistor Q2.

By such a current limiting action, the potential at the point c is regulated to a predetermined value according to the constants and characteristics of each element. That is, when a short circuit accident as described above occurs, the collector current of the transistor Q2 decreases due to the current limiting action. As a result, the potential at the point c rises to a state where the Zener diode 12 can be turned on. Therefore, the transistor Q4 is turned on in spite of the control signal a being “Hi”.
Then, the input signal e to the central control device 1 becomes "Hi", and it can be determined that an abnormality is present.

However, if this state continues for a long time, the heat generated by the transistor Q2 causes the transistor Q2 to lose heat.
1, Q2 is damaged, so if the central control unit 1 detects an abnormality, immediately take measures to stop the loom,
A process of returning the control signal a of the output port 4 to “Low” so as to turn off the transistors Q1 and Q2 is performed. At this time, the display device (not shown) can display the cause of the abnormality and the fact that the abnormality has occurred.

As described above, the short-circuit protection circuit for limiting the excessive current flowing through the driving section is provided, and the voltage-dependent element (the zener diode 12) and the switching element (the transistor Q4) are provided on the output side (point c) of the driving section. By providing a detection circuit including the above, when a short circuit accident as described above occurs, the switching element (transistors Q1 and Q2) of the driving unit
And a short circuit accident can be detected based on the output of the detection circuit.

When the electromagnetic valve 3 fails in the open mode, the control signal a from the central control unit 1 is set to “Lo”.
In the case of w ", since the photocoupler 10 is OFF,
The two-stage amplification transistors Q1 and Q2 also remain OFF. In a normal state, when the transistors Q1 and Q2 are OFF, the voltage at the connection point c becomes “Hi”, but the electromagnetic valve 3 connected to the collectors of the transistors Q1 and Q2 enters the open mode. Therefore, although the transistors Q1 and Q2 are off, the voltage level at the connection point c is close to 0 V, and the Zener diode 1
2, no current flows, and the transistor Q4 remains OFF. Therefore, the light-emitting diode 13a and the phototransistor 13b are OFF, and the inverted signal e input to the central controller 1 through the input port 5 becomes "Low". As described above, the output signal a from the central controller 1 is “Low” and the corresponding input signal e is “Low”.
If it is, it is determined that it is abnormal. As the cause of the abnormality at this time, the open mode of the electromagnetic valve 3 can be estimated. The transistor Q1 or Q2
Also has a short circuit accident, the state of the control signal a and the state of the input signal e have the same relationship as described above. Of course, in the case of such an abnormality, measures are taken to stop the loom immediately, as described above. At this time, a display device (not shown) can display the cause of the abnormality and the fact that the abnormality has occurred.

As described above, the output side (point c) of the driving section
Between the output unit (output side photocoupler 13) and the voltage dependent element (Zena diode 12),
Since the detection circuit including the switch element (transistor Q4) that turns off the transistor is provided, even if the load fails in the open mode, the abnormality can be accurately detected from the control signal a and the input signal e. .

In short, in this embodiment, the abnormality detection of the actuator drive for swinging the leading lever of the dobby machine can be performed without providing a sensor for specifically detecting the movement of the movable member in the jack lever swing mechanism.
It can be performed quickly and reliably, and when the abnormality is detected, the loom is stopped immediately, so that defective fabrics can be minimized.

In this embodiment, one electromagnetic valve 3 for controlling a fluid cylinder for swinging a jack lever used in a dobby machine has been described. However, in an actual dobby machine, For example, 16 similar electromagnetic valves 3 are attached to the upper frame and 16 to the lower frame, respectively, and the input / output ports 4 and 5 and the drive circuit 2 etc. The plurality of electromagnetic valves 3 are arranged so as to be individually controllable.

[0026]

As described above, in the present invention,
A detection unit is provided for detecting an abnormality based on the state of an output signal from the central control unit to the drive circuit and the state of a signal input to the central control unit via the drive circuit. By comparing the states, it is possible to detect an abnormality of an element or a load in the drive circuit. Therefore, it is possible to accurately detect the normal / abnormal operation of the actuator simply by performing signal processing of input / output signals from the central control device to the drive circuit.

In the present invention, the abnormality detecting means includes:
The state of the output signal from the central control device to the drive circuit at a specific time is stored, and the state of the signal input from the drive circuit to the central control device at the time corresponding to the specific time and the state of the stored output signal Since the normal or abnormal state is determined by a combination of the above, it is possible for the central control unit to determine the normal or abnormal state at a specific time.

Further, the drive circuit according to the present invention includes an input unit for receiving a signal from an output port of the central control unit, a drive unit for switching ON / OFF of a load according to the operation of the input unit, and an input of the central control unit. An output unit that outputs a signal to the port, a voltage-dependent element that operates according to the potential of the intermediate point between the drive unit and the load, and an operation state of the voltage-dependent element that is provided between the voltage-dependent element and the output unit. And a switch element that is turned ON / OFF in response to the switch element. Therefore, when the load fails in the short-circuit mode or when the load fails in the open mode, the potential state of the intermediate point can be accurately transmitted to the output unit via the switch element, and the load is short-circuited or opened. A failure in the mode can be detected.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control circuit of the device according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Central control device, 2 ... Drive circuit, 3 ... Electromagnetic valve, 4
... output port, 5 ... input port

Claims (3)

[Claims] 1. A detecting means for detecting an abnormality based on a state of an output signal from a central control unit to a drive circuit and a state of a signal input to the central control unit via the drive circuit. Abnormality detection device for actuator drive. 2. The abnormality detecting means stores a state of an output signal from the central control device to the drive circuit at a specific time, and a signal input from the drive circuit to the central control device at a time corresponding to the specific time. The abnormality detection device for driving an actuator according to claim 1, wherein normality or abnormality is determined based on a combination of the state of the output signal and the state of the stored output signal. 3. A drive circuit comprising: an input unit for receiving a signal from an output port of the central control unit; a drive unit for switching ON / OFF of a load according to an operation of the input unit; and a signal to an input port of the central control unit. And a voltage-dependent element that operates according to the potential of the intermediate point between the drive unit and the load, and is provided between the voltage-dependent element and the output unit, and is turned on according to the operation state of the voltage-dependent element. 3. The abnormality detection device for driving an actuator according to claim 2, further comprising a switch element for turning off.