JP2009208158A - Power supply circuit for multi-actuated robot and cutoff method of power supply circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply circuit for an inexpensive multi-actuated robot having simple wiring, dispensing with the consideration of a delay in signal transmission, and entirely turning off motor power supply by the disconnection of a signal line. <P>SOLUTION: In a safety unit 10 for actuating a motor power supply cutoff circuit, when having an input signal, a first input circuit 11 inputs an output signal indicating normality to a CPU 12 and a logic circuit 13, the CPU 12, upon receiving the input signal, input the output signal to the logic circuit 13 and a motor power supply cutoff circuit 19, the logic circuit 13, upon receiving the two inputs, inputs a single output to a first output circuit 14, when having an input signal, a second input circuit 16 inputs an output signal indicating normality to the CPU 12 and a second output circuit 17, and when an input to the first input circuit 11 or the second input circuit 16 is cut off, no output is transmitted, so that the CPU 12 cuts off the motor power supply cutoff circuit 19. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply circuit for a multi-axis robot provided with a plurality of multi-axis servo amplifiers and a method for shutting off the power supply circuit. The present invention relates to a power supply circuit for a multi-axis robot that can quickly stop the servo motors of other multi-axis robots when any one of them is powered off due to a disconnection accident or the like, and a method for shutting it off.

  In the case of a multi-axis robot such as an industrial robot, a motor is provided for each joint, and a motor power supply for supplying power to each motor is provided for each joint to control the plurality of robots. Has already been carried out (see Patent Document 1).

JP-A-8-194511

FIG. 8 is a block diagram of a conventional power supply circuit that controls each multi-axis robot with a plurality of multi-axis servo amplifiers.
In FIG. 8, 41 to 43 are multi-axis manipulators (one robot), 110 to 130 are multi-axis servo amplifiers, 210 to 230 are multi-axis servo motors for one robot, and 5 is a host controller. 6 is an AC power source.
The multi-axis servo motors 210 to 230 include AC servo motors 211 to 231 and encoders 212 to 232 for the AC servo motors 211 to 231, respectively.
The multi-axis servo amplifiers 110 to 130 convert power supplied from the AC power source 6 through the power supply lines 112 to 132, respectively, into controlled power and supply power to the AC servo motors 211 to 231. And servo control units 113 to 133 for controlling the power units 111 to 131, respectively.
Open / close switches 19K to 39K are respectively inserted in the middle of the power supply lines 112 to 132, and these open / close switches 19K to 39K are controlled to open and close by motor power cut-off circuits 19 to 39, respectively.
In the case of the multi-axis (three-axis in the figure) manipulators 41 to 43, for example, when the three-axis manipulator 41 is taken as an example, the three-axis manipulator 41 has three joints, so three AC servo motors 211 and three encoders 212 are used. One AC servo motor 211 (211a, 211b, 211c) and encoder 212 (212a, 212b, 212c) are provided for each joint. Since these three AC servo motors 211a, 211b, 211c and the three encoders 212a, 212b, 212c are speed-controlled and position-controlled by one multi-axis servo amplifier 110, the multi-axis servo amplifier 110 and the AC servo motor 211a , 211b and 211c are respectively connected by power lines, and the multi-axis servo amplifier 110 and the encoders 212a, 212b and 212c are respectively connected by signal lines.
The same is true between the other multi-axis servo amplifier 120 and the AC servo motor 221 and encoder 222, and between the multi-axis servo amplifier 130 and the AC servo motor 231 and encoder 232 (however, in order to make the figure easier to see, the AC servo The motors 221a, 221b, 221c, 231a, 231b, and 231c and the encoders 222a, 222b, 222c, 232a, 232b, and 232c are not shown in the figure, and are 231 and 232, respectively.
Although an example of a three-axis manipulator is shown here, the number of axes of an actual robot can be up to nine, and of course, it is not restricted to three axes.

However, any one of the three AC servo motors 211a, b, c, 221a, b, c, three AC servo motors 231a, b, c (for example, the servo motor 211b) is disconnected, etc. When power is not supplied due to a failure, the operation of the other servo motors 211a and 211c connected to the multi-axis servo amplifier 110 is stopped in the conventional power supply circuit, but connected to the other multi-axis servo amplifiers 120 and 130. The servo motors 221 and 231 are not stopped.
However, if the operation of the other motors 221 and 231 is not stopped, the arms of the other robots 42 and 43 may come into contact with the stopped robot 41 or may deviate from a predetermined range, thereby causing an unexpected accident. is there. Therefore, when operating such a plurality of multi-axis robots, when any one of the motors is not supplied with power due to a failure such as disconnection, the other motors need to be quickly stopped.
Therefore, in FIG. 8, for example, if the AC servo motor 211 b stops due to disconnection, the servo control unit 113 that detects the disconnection transmits a disconnection information signal to the other servo control units 123 and 133, and each servo control unit 123. 133 operates the motor power cut-off circuits 29 and 39 to open the open / close switches 29K and 39K to stop the rotation of the AC servo motors 221 (221a, 221b, 221c) and 231 (231a, 231b, 231c), respectively. Therefore, it is required to ensure safety.
In this case, the following three methods can be considered as signal transmission methods in which the servo control unit 113 that detects the disconnection transmits the disconnection information signal to the other servo control units 123 and 133.
Hereinafter, for the sake of simplicity, a case where signals are transmitted between the three control units 311 to 331 will be described as an example.

(1) All units all input / output methods:
One is the “all unit all input / output system” shown in FIG.
In FIG. 9, each of the units 311 to 331 has one CPU, one output circuit, and two input circuits, respectively, and outputs from the unit 3111 to the other two units 321 and 331 and the other two. The units 321 and 331 are connected so as to be input to the unit 311 respectively. Similarly, the unit 321 outputs to the other two units 331 and 311 and the other two units 331 and 311 to the unit 321. To the other two units 311 and 321, and the other two units 311 and 321 are connected to the unit 331, respectively.

(2) Common PLC installation method:
The second is the “common PLC installation method” shown in FIG.
In FIG. 10, each unit 311a to 331a has one CPU, an output circuit, and an input circuit, and a common programmable logic controller (PLC) is provided to output the PLC from each of the units 311a to 331a to the PLC. To the units 311a to 331a. According to this, when the output signal of the unit 311a is output to the PLC, the PLC inputs the input signal to the input circuits of the other units 321a and 331a. The operation when the other units 321a and 331a output is the same.

(3) Open collector method:
The third is the “open collector method” shown in FIG.
In FIG. 11, each of the units 311b to 331b includes one CPU, one output circuit, one input circuit and one transistor, and an output circuit is connected to the base of each transistor and input to its collector. The circuit is connected and connected so as to apply a predetermined voltage via a pull-up resistor 91 in common.
In such a circuit, when the output signal is not applied to the base of the transistor of the unit 311b, the transistor is open, so the input circuits of the other units 321b and 331b are the input signal H. On the other hand, when an output signal is applied to the base of the transistor of the unit 311b, the transistor is closed, and the transistor side of the resistor 91 changes to a low potential, so that the input circuits of the other units 321b and 331b change to the input signal L. The output signal from the output circuit of the unit 311b is input to the input circuits of the units 321b and 331b.
The operation when the other units 321b and 331b output is the same.

However, each of these three methods has the following drawbacks.
(1) Disadvantages of all unit I / O methods:
In the case of “all unit all input / output method” in FIG. 9, the number of wires is 6 when the number of units is 3, but the number of wires rapidly increases to n (n−1) when the number of units is n. There is a drawback that the wiring becomes complicated as the number of units increases.
(2) Disadvantages of common PLC installation method:
In the case of the “common PLC installation method” in FIG. 10, an expensive PLC is required and it is necessary to consider a delay in signal transmission caused by relaying the PLC.
(3) Disadvantages of the open collector method:
In the case of the “open collector method” in FIG. 11, if a signal line is disconnected, information is not transmitted to all other units, and it is necessary to provide a pull-up resistor 91 in at least one place. There was a disadvantage that the power supply of could not be separated.
(4) Object of the present invention:
The present invention has been made to solve these drawbacks. The object of the present invention is that the wiring is not complicated, an expensive PLC is not required, and it is not necessary to consider the delay in signal transmission due to relaying. Another object of the present invention is to provide a power supply circuit for a multi-axis robot that can separate the power sources of the respective units and can report the occurrence of the disconnection to all the units regardless of where the signal lines are disconnected.

In order to solve the above problem, the invention of the power supply circuit for a multi-axis robot according to claim 1
An AC power source, a multi-axis servo amplifier that converts the power from the AC power source into controlled power and supplies the motor to a plurality of motors used for each joint of the multi-axis robot, and the multi-axis servo from the AC power source In a power supply circuit for a multi-axis robot comprising an open / close switch provided on a common power supply path to an amplifier, and a motor power supply cut-off circuit for opening / closing the open / close switch, the motor power cut-off circuit is controlled And each safety unit includes first and second input circuits, first and second output circuits, one CPU, and one logic circuit, and the first input circuit is a pre-stage. When there is an input signal from the first output circuit of the safety unit, the CPU outputs the output signal to the CPU and the logic circuit. When the input signal is input, the CPU outputs the output signal to the logic circuit and the previous logic circuit. When the two input signals are input, the logic circuit outputs an output signal to the first output circuit, and the input signal from the second output circuit of the preceding safety unit is the second input. Upon entering the circuit and the second output circuit, the second input circuit outputs an input signal to the CPU, the second output circuit outputs an output signal to the next safety unit, and the first input circuit or the The second input circuit is characterized in that, when there is no input signal, no output signal is output, so that no input signal is input to the CPU, and the CPU shuts off the motor power supply cutoff circuit.
According to a second aspect of the present invention, in the power supply circuit for the multi-axis robot according to the first aspect, an abnormality detection circuit for detecting an abnormal operation of the multi-axis robot is provided in the safety unit, and a signal indicating that the abnormality detection circuit is abnormal is provided. By inputting to the CPU, the CPU cuts off the motor power cut-off circuit.
According to a third aspect of the present invention, there is provided an AC power source and a plurality of motors used for each joint of the multi-axis robot by converting power from the AC power source into controlled power. A multi-axis servo amplifier that supplies the multi-axis servo amplifier, an open / close switch provided in a common power supply path from the AC power source to the multi-axis servo amplifier, and a motor power shut-off circuit that opens and closes the open / close switch. A power supply circuit for a multi-axis robot comprising: a safety unit for controlling the motor power supply cut-off circuit; and each safety unit includes a first input circuit, a second input circuit, a first output circuit, and a second output circuit. And one CPU and one logic circuit, and the first input circuit sends an output signal to the CPU and the logic circuit when there is an input signal from the first output circuit of the preceding safety unit. A step of outputting, when the CPU receives the input signal, a step of outputting an output signal to the logic circuit and the motor power cut-off circuit; and the logic circuit outputs an output signal when the two input signals are input. When the input signal from the second output circuit of the preceding safety unit enters the second input circuit and the second output circuit, the second input circuit outputs the input signal to the CPU. And the second output circuit includes an output step for outputting the output signal to the next safety unit, so that the first input circuit or the second input circuit does not output the output signal when there is no input signal. When there is no input signal from the front stage, the motor power cutoff circuit is operated, and the front stage and rear stage power cutoff circuits are also operated.
According to a fourth aspect of the present invention, in the multi-axis robot power supply circuit cutoff method according to the third aspect, an abnormality detection circuit for detecting an abnormal operation of the multi-axis robot is provided in the safety unit, and the abnormality detection circuit is The step of outputting a signal to the CPU causes the CPU to cut off the motor power cut-off circuit.

  With the above configuration, the conventional abnormality detection CPU is also used to cut off the motor power supply at the time of disconnection, so that it is not necessary to separately require an expensive PLC, and it is necessary to consider the delay in signal transmission due to relaying Therefore, the power supply of each unit can be separated, and the occurrence of disconnection can be reported to all the units regardless of where the disconnection occurs in the signal line.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a power supply circuit for a multi-axis robot according to the present invention.
In FIG. 1, reference numeral 100 denotes a power supply circuit for a multi-axis robot according to the present invention. In the figure, the same reference numerals as those in FIG. 8 are the same as the elements described in FIG. Reference numerals 10, 20, and 30 denote safety units according to the present invention that operate the motor power cutoff circuits 19, 29, and 39, respectively. The safety units 10, 20, and 30 are connected to the front and rear safety units through communication lines L12 and L23, respectively.

FIG. 2 is a diagram showing an internal configuration of each safety unit 10-30 and a wiring relationship between each safety unit 10-30. The configuration of the safety unit 10 in FIG. 2 is the same as the configuration of the other safety units 20 and 30, except that the safety unit 10 is a terminal when it is composed of three manipulators. The input is different from the other safety units 20 and 30 in that the level is fixed to be “H”.
Hereinafter, the safety unit 10 will be described.
<Internal configuration and wiring relationship of safety unit 10>
The safety unit 10 includes a first input circuit (A) 11, a second input circuit (B) 16, a first output circuit (A) 14, a second output circuit (B) 17, one CPU 12, and one logic circuit. (For example, an AND circuit) 13.
The first input circuit 11 has an input signal (1) that is normal when an input signal is input. (Note: In FIG. 2, the symbol of circle 1 is used, but in the specification, the symbol of circle 1 cannot be used. The same applies hereinafter) to the CPU 12 and the logic circuit 13, respectively. When the input signal (1) is input, the CPU 12 outputs a normal CPU output signal (2) to the logic circuit 13 and a CPU output signal (7) to the motor power cutoff circuit 19 as a normal signal. Therefore, the motor power cutoff circuit 19 does not perform a cutoff operation.
When the input signal (1) from the first input circuit 11 and the CPU output signal (2) from the CPU 12 are input, the logic circuit 13 outputs a normal output signal to the first output circuit 14, and the first output circuit 14 When the output signal is input, the normal output signal (3) is output to the first input circuit (A) 21 of the adjacent safety unit 20.
On the other hand, on the feedback side of the safety unit 10, when the output signal (5 ′) from the second output circuit 27 of the adjacent safety unit 20 enters the second input circuit 16 and the second output circuit 17, the second input circuit 16. Outputs a normal input signal (4) to the CPU 12, and the second output circuit 17 outputs a normal output signal (5) to a downstream safety unit (not shown). When the input signal (4) is received, the CPU 12 outputs a normal CPU output signal (2) to the logic circuit 13 and a CPU output signal (7) to the motor power shut-off circuit 19 as a normal signal. Therefore, the motor power cutoff circuit 19 does not perform a cutoff operation.
Hereinafter, the internal configuration and wiring relationship of the safety unit 20 and the safety unit 30 are the same. However, at the final end (the safety unit 30 in the figure), the output signal (3 ″) from the first output circuit 34 of the safety unit 30 does not have an adjacent safety unit, so its own second input circuit 36 and second output circuit. The point which feeds back to the input side of 37 differs from the other safety units 10 and 20.
The above is a normal case where there is an input to the first input circuit 11 and the second input circuit 16, but a case where there is no input to the first input circuit 11 and the second input circuit 16 will be described.
<When there is no input in the first input circuit 11>
Therefore, when the input to the first input circuit 11 is cut off, the first input circuit 11 does not output the input (1) to the next circuit, so that the CPU 12 does not receive the input signal (1). An output for opening the opening / closing switch 19K is output to 19, and power supply to the motor is stopped. Since the logic circuit 13 does not have one input signal, the logic circuit 13 does not output the output signal (3) to the first output circuit 14, and therefore the first output circuit 14 outputs the output signal (3) to the input circuit 21 of the adjacent safety unit 20. Will not be output.
<When there is no input in the second input circuit 16>
Further, when the input to the second input circuit 16 is cut off, the second input circuit 16 does not output the input signal (4) to the CPU 12, and thus the CPU 12 does not receive the input signal (4). The output for opening the open / close switch 19K is output to stop the power supply to the motor. Further, the second output circuit 17 does not output the output signal (5) to the adjacent safety unit (not shown).

<When an abnormality signal (6) is input from the abnormality detection circuit 15 to the CPU 12>
The safety unit 10 has an abnormality detection circuit 15 provided in the conventional apparatus.
When the motor rotation speed is high enough to deviate from the predetermined range, or when the robot arm deviates from the predetermined safe range, the encoder or the dedicated sensor detects this and signals that the abnormality detection circuit 15 is abnormal. Send. When the abnormality detection circuit 15 receives the abnormality signal, it sends an abnormality signal (6) to the CPU 12, whereby the CPU 12 outputs an output for opening the open / close switch 19K to the motor power shut-off circuit 19 to the motor 211 (FIG. 1). Stop the power supply.
The configuration and operation of the safety unit 10 described above are the same for the safety units 20 and 30.

<Specific circuit of safety unit 10>
FIG. 3 is a specific circuit diagram showing an example for realizing the internal configuration of the safety unit 10 of FIG. The safety unit 10 in FIG. 3 has the same configuration as the other safety units 20 and 30 except that the input of the first input circuit 11 is fixed at the “H” level as described above. Hereinafter, the internal configuration of the safety unit 10 will be described.
The first input circuit 11 is realized by a photocoupler. When there is an input signal in the first input circuit 11, the light emitting element emits light with the VCC2 voltage, and the light receiving element receives the light and becomes conductive, and the input becomes equal to the VCC1 potential. The signal (1) is input to the next CPU 12 and logic circuit 13.
The first output circuit 14 is also realized by a photocoupler. When the output signal from the logic circuit 13 enters the first output circuit 14, the light emitting element emits light, and the light receiving element receives the light and becomes conductive, and is equal to the VCC2 potential. The output signal (3) is output to the adjacent safety unit.
The second input circuit 16 is also realized by a photocoupler. When there is an input signal in the second input circuit 16, the two light emitting elements connected in series emit light, and the light receiving element receives the light and becomes conductive. The input signal (4) equal to the potential is input to the next CPU 12, and the light emitting element of the second output circuit 17 which is also realized by a photocoupler emits light, and the light receiving element receives the light and becomes conductive. The output signal (5) equal to the VCC2 potential is output to the adjacent safety unit.

Next, the operation of the motor power cutoff circuit according to the present invention when a disconnection occurs will be described. For the convenience of explanation,
(A) When a disconnection occurs on the way from the safety unit 10 to the safety unit 20 (outward path),
(B) First, the instantaneous operation of all the motor power cut-off circuits in the two cases where a disconnection occurs on the way from the safety unit 30 to the safety unit 20 (return path) will be described.

<A: Disconnection on the output side of the outbound path of the safety unit 10>
FIG. 4 is a diagram illustrating a timing chart of each part in each safety unit when a disconnection occurs on the way from the safety unit 10 to the safety unit 20. The safety units 10, 20, and 30 are in order from the top.
In the safety unit 10, in order from the top, (a) an abnormal signal (6) output from the abnormality detection circuit 15 (normal at H, abnormal at L), (b) an input signal (1) output from the first input circuit (A) 11 ), (C) CPU output signal (2) issued by CPU 12, (d) shut-off signal issued by motor power shut-off circuit 19 (closed at H, shut off at L), (e) issued by first output circuit (A) 14 The output signals (3), (f) the input signal (4) output from the second input circuit (B) 16 and (g) the output signal (5) output from the second output circuit (B) 17 are shown.
Further, in the safety unit 20, in order from the top, (a) an abnormality signal (6 ′) output from the abnormality detection circuit 25 (normal at H, abnormal at L), (b) input from the first input circuit (A) 21. Signal (1 ′), (C) CPU output signal (2 ′) output from CPU 22, (D) Shut-off signal output from motor power shut-off circuit 29 (closed at H, shut off at L), (E) First output circuit ( A) Output signal (3 ′) output by 24, (f) Input signal (4 ′) output by the second input circuit (B) 26, (G) Output signal (5 ′) output by the second output circuit (B) 27 ) Respectively.
In the safety unit 30, in order from the top, (a) an abnormality signal (6 ″) output from the abnormality detection circuit 35 (normal in H, abnormal in L), and (b) input output from the first input circuit (A) 31. Signal (1 ″), (C) CPU output signal (2 ″) output from CPU 32, (D) Shut-off signal output from motor power shut-off circuit 39 (closed at H, shut off at L), (E) First output circuit ( A) Output signal (3 ″) output from 34, (f) Input signal (4 ″) output from the second input circuit (B) 36, (G) Output signal (5 ″ output from the second output circuit (B) 37 ) Respectively.

(I) (Stop of AC servo motor 221)
Therefore, the signal line between the first output circuit 14 (FIG. 2) of the safety unit 10 and the first input circuit 21 (FIG. 2) of the safety unit 20 is disconnected at time t1. When this occurs, each part until time t1 is normal, but first, the output signal (1 ′) output from the first input circuit (A) 21 (FIG. 2) of the safety unit 20 is changed from H → L. It becomes. The “L” output signal (1 ′) from the first input circuit 21 is input to the CPU 22, and the output of the CPU 22 is changed from the “H” output signal (7 ′) to the “L” output signal (7 ′). The motor power cut-off circuit 29 is cut off, and the motor power cut-off circuit 29 cuts off the open / close switch 29K, and the AC servo motor 221 (FIG. 1) stops.

(Ii) (Stop of AC servo motor 231)
Further, the “L” output signal (1 ′) from the first input circuit 21 of the safety unit 20 is input to one of the input terminals of the logic (AND) circuit 23, so that AND (when both input terminals are “H”). The output signal (3 ′) from the logic circuit 23 to the output circuit 24 becomes “L”, which enters the input circuit 31 of the safety unit 30. When the “L” output signal (3 ′) is input to the input circuit 31, the input circuit 31 sends the “L” input signal (1 ″) to the CPU 32, and the output signal (7 ″) of the CPU 32 is from “H” until then. This becomes “L”, and this is sent to the motor power cut-off circuit (FIG. 1) 39. The motor power cut-off circuit 39 cuts off the open / close switch 39K (FIG. 1), and the AC servo motor 231 (FIG. 1) stops.

(Iii) (Stop of AC servo motor 211)
Further, the “L” output signal (1 ″) from the first input circuit 31 of the safety unit 30 enters one of the input terminals of the logic (AND) circuit 33, so that the AND condition is broken, and the logic circuit 33 The output signal to the output circuit 34 becomes “L”, and the “L” output signal (3 ″) from the first output circuit 34 enters the second output circuit 37 by the feedback system of the safety unit 30. The second output circuit 37. When the “L” output signal (3 ″) is input to the second output circuit 37, the second output circuit 37 sends the “L” output signal (5 ″) to the second output circuit 27 of the adjacent safety unit 20. L "output signal (5 ') is sent to the second input circuit 16 of the adjacent safety unit 10. The second input circuit 16 sends an “L” input signal (4) to the CPU 12, and the output signal (7) of the CPU 12 changes from “H” to “L” until then, and this is sent to the motor power shutoff circuit (FIG. 1) 19. The motor power cut-off circuit 19 cuts off the open / close switch 19K (FIG. 1), and the AC servo motor 211 (FIG. 1) stops.

  As described above, when the disconnection occurs at the time t1 on the way from the safety unit 10 to the safety unit 20, according to the present invention, all the motor power cut-off circuits 19, 29, 39 operate instantaneously, The open / close switches 19K to 39K (FIG. 1) are opened, and all of the AC servo motors 211 to 231 are instantaneously stopped, thereby ensuring safety.

<B: Disconnection on the return path side of the safety unit 30>
FIG. 5 is a diagram illustrating a timing chart of each part in each safety unit when a disconnection occurs on the way from the safety unit 30 to the safety unit 20. The safety units 10, 20, and 30 are in order from the top.
(I) (Stop of AC servo motor 221)
Therefore, the signal line between the second output circuit 37 (FIG. 2) of the safety unit 30 and the second input circuit 26 (FIG. 2) of the safety unit 20 is disconnected at the time t2. However, first, the output signal (4 ′) output from the second input circuit (B) 26 (FIG. 2) of the safety unit 20 is changed from H → L. It becomes. The “L” input signal (4 ′) from the second input circuit 26 is input to the CPU 22, and the output of the CPU 22 is changed from the “H” output signal (7 ′) to the “L” output signal (7 ′). The motor power cut-off circuit 29 is cut off, and the motor power cut-off circuit 29 cuts off the open / close switch 29K, and the AC servo motor 221 (FIG. 1) stops.

(Ii) (Stop of AC servo motor 211)
Further, the output signal (5 ′) output from the second output circuit (B) 27 (FIG. 2) of the safety unit 20 changes from H → L. The “L” output signal (5 ′) from the second output circuit 27 enters the second input circuit (B) 16 (FIG. 2) of the adjacent safety unit 10, and the input signal (4) output from the second input circuit 16 Becomes H → L. The "L" input signal (4) from the second input circuit 16 is input to the CPU 12, and the output of the CPU 12 becomes the "L" output signal (7) from the previous "H" output signal (7), which is the motor power shut-off. The motor power cut-off circuit 19 cuts off the open / close switch 19K, and the AC servo motor 211 (FIG. 1) stops.

(Iii) (Stop of AC servo motor 231)
The “L” input signal (4 ′) from the second input circuit 26 of the safety unit 20 enters the CPU 22, and the CPU 22 sends the “L” CPU output signal (2 ′) to the input terminal of the logic (AND) circuit 23. By sending to one side, the AND condition breaks down, the output signal from the logic circuit 23 to the output circuit 24 becomes “L”, and the “L” output signal (3 ′) of the output circuit 24 becomes the first safety unit 30 of the adjacent safety unit 30. The input circuit 31 is entered. When the “L” output signal (3 ′) is input to the first input circuit 31, the first input circuit 31 sends the “L” input signal (1 ″) to the CPU 32, and the output signal (7 ″) of the CPU 32 is From “H” to “L”, this is sent to the motor power cut-off circuit (FIG. 1) 39, the motor power cut-off circuit 39 cuts off the open / close switch 39K (FIG. 1), and the AC servo motor 231 (FIG. 1) is turned on. Stop.

  As described above, when the disconnection occurs at the time t2 in the middle from the safety unit 30 to the safety unit 20, according to the present invention, all the motor power cutoff circuits 19, 29, 39 operate instantaneously, The open / close switches 19K to 39K (FIG. 1) are opened, and all of the AC servo motors 211 to 231 are instantaneously stopped, thereby ensuring safety.

As described above, according to the present invention, when the disconnection occurs in the forward path of the safety unit 10 → 20 in A and the disconnection occurs in the return path of the safety unit 30 → 20 in B, all the motor power supplies are instantaneously interrupted by the present invention. Will be.
Also, when disconnection occurs at other locations (ie, disconnection upstream of the safety unit 10, disconnection at the safety unit 20 → 30, disconnection at the feedback of the safety unit 30 → 30, disconnection at the safety unit 20 → 10) In the case of disconnection in the safety units 10, 20, and 30), according to the present invention, all the motor power supplies are instantaneously cut off by the same sequence.
Next, regarding the operation of the motor power shut-off circuit according to the present invention when the abnormality detection circuit transmits an abnormality in the safety unit, (c) when the abnormality detection circuit in the safety unit 10 detects an abnormality, and (d ) The instantaneous operation of all the motor power cutoff circuits for two examples when the abnormality detection circuit in the safety unit 30 detects an abnormality will be described.

<C: When an abnormality is detected in the safety unit 10>
FIG. 6 is a diagram illustrating a timing chart of each part in each safety unit when an abnormality is detected in the safety unit 10. The safety units 10, 20, and 30 are in order from the top.
(I) (Stop of AC servo motor 211)
When the abnormality detection circuit 15 (FIG. 2) of the safety unit 10 detects an abnormality at time t3, each part until time t3 was normal, but from time t3, the signal (6) from the abnormality detection circuit 15 is The “L” signal (6) is sent to the CPU 12. Therefore, the CPU 12 sends the “L” CPU output signal (7) to the motor power cut-off circuit 19 (FIG. 2), and the motor power cut-off circuit 19 (FIG. 1) cuts off the open / close switch 19K (FIG. 1). The servo motor 211 (FIG. 1) stops.

(Ii) (Stop of AC servo motor 221)
Further, the CPU 12 sends the “L” CPU output signal (2) to one of the input terminals of the logic (AND) circuit 13, so that the AND condition is broken, and the output signal from the logic circuit 13 to the first output circuit 14 is The “L” output signal (3) of the first output circuit 14 enters the first input circuit 21 of the adjacent safety unit 20. When the “L” output signal (3) is input to the first input circuit 21, the first input circuit 21 sends the “L” input signal (1 ′) to the CPU 22, and the output signal (7 ′) of the CPU 22 is “ From “H” to “L”, this is sent to the motor power cut-off circuit 29 (FIG. 2), and the motor power cut-off circuit 29 (FIG. 1) cuts off the open / close switch 29K (FIG. 1), and the AC servomotor 221 (FIG. 1) stops.

(Iii) (Stop of AC servo motor 231)
Further, the CPU 22 of the safety unit 20 sends the “L” CPU output signal (2 ′) to one of the input terminals of the logic circuit 23, so that the AND condition is broken, and the output from the logic circuit 23 to the first output circuit 24. The signal becomes “L”, and the “L” output signal (3 ′) of the first output circuit 24 enters the first input circuit 31 of the adjacent safety unit 30. When the “L” output signal (3 ′) is input to the first input circuit 31, the first input circuit 31 sends the “L” input signal (1 ″) to the CPU 32, and the output signal (7 ″) of the CPU 32 is From “H” to “L”, this is sent to the motor power cut-off circuit 39 (FIG. 2). The motor power cut-off circuit 39 (FIG. 1) cuts off the open / close switch 39K (FIG. 1), and the AC servomotor 231 ( FIG. 1) stops.

  As described above, when an abnormality is detected in the safety unit 10, according to the present invention, all the motor power cutoff circuits 19, 29, 39 operate instantaneously, and all the open / close switches 19K to 39K (FIG. 1). ) Is opened, and all of the AC servomotors 211 to 231 are instantaneously stopped, thereby ensuring safety.

<D: When an abnormality is detected in the safety unit 30>
FIG. 7 is a diagram illustrating a timing chart of each part in each safety unit when an abnormality is detected in the safety unit 30, which are the safety units 10, 20, and 30 in order from the top.
(I) (Stop of AC servo motor 231)
When the abnormality detection circuit 35 (FIG. 2) of the safety unit 30 detects an abnormality at time t4, each part up to time t3 was normal, but from time t3, the signal (6 ″) from the abnormality detection circuit 35 is The “L” signal (6 ″) is changed from “H” to “L” until then, and this “L” signal (6 ″) is sent to the CPU 32. Therefore, the CPU 32 sends the “L” CPU output signal (7 ″) to the motor power cut-off circuit 39 ( 2), the motor power cut-off circuit 39 (FIG. 1) cuts off the open / close switch 39K (FIG. 1), and the AC servo motor 231 (FIG. 1) stops.

(Ii) (Stop of AC servo motor 221)
The CPU 32 of the safety unit 30 inputs the “L” CPU output signal (2 ″) to one of the input terminals of the logic circuit 33, thereby breaking the AND condition, and the output signal from the logic circuit 33 to the first output circuit 34 is The “L” output signal (3 ″) from the first output circuit 34 enters the second output circuit 37 by the feedback system of the safety unit 30. The “L” output signal (3 ")", The second output circuit 37 sends an "L" output signal (5 ") to the second input circuit 26 of the adjacent safety unit 20. The second input circuit 26 sends an" L "input signal (4) to the CPU 22. '), The CPU 22 sends a CPU output signal (7') to the motor power cut-off circuit 29 (FIG. 2), and the motor power cut-off circuit 29 (FIG. 1) cuts off the open / close switch 29K (FIG. 1). Servo motor 221 (FIG. 1) To stop.

(Iii) (Stop of AC servo motor 211)
Further, the second output circuit 37 of the safety unit 30 sends the “L” output signal (5 ″) to the second output circuit 27 of the adjacent safety unit 20, and the second output circuit 27 outputs the “L” output signal (5 ′). ) Is further sent to the second input circuit 16 of the adjacent safety unit 10. The second input circuit 16 sends an “L” input signal (4) to the CPU 12, and the output signal of the CPU 12 (7 changes from “H” to “L” until then, and this is sent to the motor power shutoff circuit 19 (FIG. 2). Then, the motor power cut-off circuit 19 (FIG. 1) cuts off the open / close switch 19K (FIG. 1), and the AC servo motor 211 (FIG. 1) stops.

As described above, when an abnormality is detected in the safety unit 30, according to the present invention, all the motor power cutoff circuits 19, 29, 39 operate instantaneously and all the open / close switches 19K to 39K (FIG. 1). ) Is opened, and all of the AC servomotors 211 to 231 are instantaneously stopped, thereby ensuring safety.
The above is the same when an abnormality is detected in the safety unit 20, and according to the present invention, all the motor power shut-off circuits 19, 29, 39 operate in the same sequence as described above, and the AC servo motor 211 is operated. All of .about.231 stop instantaneously.

It is a block diagram of a power supply circuit for a multi-axis robot according to the present invention. It is a figure which shows the internal structure of each safety unit, and the wiring relationship between each safety unit. FIG. 3 is a specific circuit diagram as an example of an internal configuration of the safety unit in FIG. 2. It is a figure which shows the timing chart of each site | part in each safety unit when a disconnection generate | occur | produces in the way from the safety unit to the safety unit. It is a figure which shows the timing chart of each site | part in each safety unit when a disconnection generate | occur | produces in the way from the safety unit 30 to the safety unit. It is a figure which shows the timing chart of each site | part in each safety unit when abnormality is detected in the safety unit. It is a figure which shows the timing chart of each site | part in each safety unit when abnormality is detected in the safety unit. It is a block diagram of the conventional power supply circuit for multi-axis robots. It is a block diagram explaining the conventional all unit all input / output system. It is a block diagram explaining the conventional common PLC installation system. It is a block diagram explaining the conventional open collector system.

Explanation of symbols

100 Power supply circuit for multi-axis robot according to the present invention 10, 20, 30 Safety unit 11, 21, 31 First input circuit (A)
12, 22, 32 CPU
13, 23, 33 Logic circuit (AND circuit)
14, 24, 34 First output circuit (A)
15, 25, 35 Abnormality detection circuit 16, 26, 36 Second input circuit (B)
17, 27, 37 Second output circuit (B)
19, 29, 39 Motor power cut-off circuit 19K, 29K, 39K Open / close switches L12, L23, communication lines 41-43 Multi-axis manipulator (multi-axis robot)
110, 120, 130 Multi-axis servo amplifier 111, 121, 131 Power unit 112, 122, 132 Feed line 113, 123, 133 Control unit 210, 220, 230 Multi-axis servo motor 211, 221, 231, 211a, 211b, 211c AC servo motor 212, 222, 232, 212a, 212b, 212c Encoder 5 Host controller 6 AC power supply

Claims (4)

An AC power source, a multi-axis servo amplifier that converts the power from the AC power source into controlled power and supplies the motor to a plurality of motors used for each joint of the multi-axis robot, and the multi-axis servo from the AC power source In a power supply circuit for a multi-axis robot comprising: an open / close switch provided in a common power supply path to an amplifier; and a motor power cut-off circuit for opening and closing the open / close switch,
A safety unit for controlling the motor power cutoff circuit; and each safety unit includes a first and second input circuit, a first and second output circuit, one CPU, and one logic circuit. Prepared,
The first input circuit outputs an output signal to the CPU and the logic circuit when there is an input signal from the first output circuit of the preceding safety unit;
When the CPU receives the input signal, the CPU outputs an output signal to the logic circuit and the motor power cut-off circuit.
The logic circuit outputs an output signal to the first output circuit when two input signals are input,
When an input signal from the second output circuit of the preceding safety unit enters the second input circuit and the second output circuit, the second input circuit outputs the input signal to the CPU, and the second output circuit Output the output signal to the next safety unit,
The first input circuit or the second input circuit does not output an output signal when there is no input signal, so that no input signal is input to the CPU, and the CPU shuts down the motor power supply cutoff circuit. Power supply circuit for multi-axis robots.   An abnormality detection circuit for detecting an abnormal operation of the multi-axis robot is provided in the safety unit, and the CPU causes the motor power cutoff circuit to perform an interruption operation by outputting a signal that the abnormality detection circuit makes an abnormality to the CPU. The power circuit for a multi-axis robot according to claim 1. An AC power source, a multi-axis servo amplifier that converts the power from the AC power source into controlled power and supplies the motor to a plurality of motors used for each joint of the multi-axis robot, and the multi-axis servo from the AC power source In a method for shutting off a power supply circuit for a multi-axis robot, comprising: an open / close switch provided in a common power supply path to an amplifier; and a motor power shut-off circuit that opens and closes the open / close switch.
A safety unit for controlling the motor power cutoff circuit; and each safety unit includes a first and second input circuit, a first and second output circuit, one CPU, and one logic circuit. Prepared,
The first input circuit outputs an output signal to the CPU and the logic circuit when there is an input signal from the first output circuit of the preceding safety unit;
The CPU outputs an output signal to the logic circuit and the motor power cut-off circuit when the input signal is input;
The logic circuit outputs an output signal to the first output circuit when two input signals are received;
When an input signal from the second output circuit of the preceding safety unit enters the second input circuit and the second output circuit, the second input circuit outputs the input signal to the CPU, and the second output circuit Since the output step is output to the next safety unit, the first input circuit or the second input circuit does not output the output signal when there is no input signal, so there is no input signal from the previous stage. And a power supply circuit for a multi-axis robot, wherein the power supply circuit for the multi-axis robot is operated while the motor power supply circuit is operated.   An abnormality detection circuit for detecting an abnormal operation of the multi-axis robot is provided in the safety unit, and the CPU causes the motor power supply cutoff circuit to perform an interruption operation by outputting a signal that the abnormality detection circuit makes an abnormality to the CPU. The method for shutting off a power supply circuit for a multi-axis robot according to claim 3.

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