JP7398947B2 - motor control device - Google Patents

Description

The present invention relates to a motor control device that performs drive control of a motor based on a position command from a controller.

For example, a motor control device used in a machine that processes, molds, etc. a workpiece (hereinafter referred to as a processing machine) controls the drive of a motor within the processing machine based on instructions from a controller. It is configured.

BACKGROUND ART In motor control devices used in processing machines, an abnormality, including a power outage, that prevents the motor from being driven normally may occur during operation of the processing machine. In consideration of such a case, the motor control device is required to have a function that can forcibly terminate machining and retreat the tool and workpiece to a position where they do not interfere.

Note that an abnormality in which the motor cannot be driven normally includes, in addition to a power outage, a case in which the motor cannot be driven to correctly follow a command from the controller.

There is a conventional technique in which the vehicle is stopped according to a preset evacuation time or evacuation distance when an abnormality occurs (see, for example, Patent Document 1). Patent Document 1 discloses a technique in which a command from a controller is stored, and when an abnormality occurs, the stored command is used to perform an evacuation operation.

International Publication No. 2012/176268

When a conventional technique is used to forcibly terminate machining and immediately stop the apparatus when an abnormality occurs, there is a possibility that a shock may be given to the machining machine. That is, when performing such control, there is a risk that mechanical parts may be damaged or the workpiece may be scratched.

In conventional control, the vehicle is decelerated and stopped based on a preset evacuation time or evacuation distance. In this case, depending on the timing when the abnormality occurs, there is a possibility that the processing machine will operate along a trajectory different from the originally planned trajectory due to the shock applied to the processing machine, which may cause damage to the workpiece. be.

Furthermore, in the prior art described in Patent Document 1, when an abnormality occurs, an evacuation operation is immediately performed in which the command is reversely followed. Therefore, if the shock is large, there is a problem that the workpiece, tools such as cutting blades, or processing machines may be damaged.

The present invention has been made in view of the above, and an object of the present invention is to obtain a motor control device that can decelerate and stop along the trajectory of normal operation when an abnormality occurs.

The motor control device according to the present invention sequentially buffers the position commands output from the controller in each command cycle, from the first position command buffered first to the Nth position command buffered last. A buffer that temporarily stores N position commands up to the command, a command generation unit that generates a reference position command for each command cycle based on the N position commands temporarily stored in the buffer, and a command generation unit that generates a reference position command. a motor control unit that controls the position of a motor to be controlled by receiving a reference position command that has been set every command cycle; and an abnormality detection unit that detects an abnormal state in which a position command is not normally output from the controller; If no abnormal state is detected in the abnormality detection section, the command generation section uses the first position command outputted from the controller N command cycles ago and temporarily stored in the buffer as a reference position command, and performs abnormality detection. When an abnormal state is detected in the part, by utilizing the N position commands buffered in the buffer before the abnormal state was detected, the difference between adjacent position commands among the N position commands is A complementary process is executed to generate a complementary position command by complementing one or more additional position commands, and the complementary position command is used as a reference position command for each command cycle, and the motor is moved along the trajectory that was planned for normal operation. It decelerates and stops.

According to the present invention, it is possible to obtain a motor control device that can decelerate and stop along the trajectory of normal operation when an abnormality occurs.

1 is a system configuration diagram including a motor control device according to Embodiment 1 of the present invention. FIG. 7 is an explanatory diagram regarding a method for generating a reference position command by a command generation unit when an abnormal state is detected in the first embodiment of the present invention. In the motor control device according to Embodiment 1 of the present invention, the transition of speed and position when processing is performed in the order of (state 1), (state 2), (state 3), and (state 4) is shown. This is a diagram. FIG. 2 is a functional block diagram showing a state in which the motor control device according to Embodiment 1 of the present invention executes operation 1; FIG. 3 is a diagram showing temporal changes in speed waveforms and position waveforms when the motor control device according to Embodiment 1 of the present invention executes operation 1; FIG. 2 is a functional block diagram showing a state in which the motor control device according to Embodiment 1 of the present invention executes operation 2; FIG. 6 is a diagram showing temporal changes in speed waveforms and position waveforms when the motor control device according to Embodiment 1 of the present invention executes operation 2; FIG. 2 is a functional block diagram showing a state in which the motor control device according to Embodiment 1 of the present invention executes operation 3; FIG. 6 is a diagram showing temporal changes in speed waveforms and position waveforms when the motor control device according to Embodiment 1 of the present invention executes operation 3; FIG. 2 is a functional block diagram showing a state in which the motor control device according to Embodiment 1 of the present invention executes operation 4; FIG. 6 is a diagram showing temporal changes in a speed waveform and a position waveform when the motor control device according to Embodiment 1 of the present invention executes operation 4; FIG. 2 is a system configuration diagram including a motor control device according to Embodiment 2 of the present invention. In the motor control device according to Embodiment 2 of the present invention, an abnormal state is detected while the two-axis motor is performing circular motion, and the locus of position transition is shown when operations 1 to 4 are executed. FIG.

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1.
FIG. 1 is a system configuration diagram including a motor control device according to Embodiment 1 of the present invention. The motor control device 10 according to the first embodiment performs position control of the motor 2 based on a position command from the controller 1. The motor control device 10 includes a buffer 11, a command generation section 12, a motor control section 13, an abnormality detection section 14, and a past storage section 15.

Next, the functions of the controller 1 and the functions of each component included in the motor control device 10 will be explained. The controller 1 sequentially outputs position commands as the absolute position of the motor 2 according to the command cycle. A buffer 11 in the motor control device 10 sequentially buffers position commands output from the controller at each command cycle. Specifically, N position commands corresponding to the latest N command cycles are buffered in the buffer 11 .

Here, in the following explanation, among the N position commands, the position command buffered first will be referred to as the first position command, and the position command buffered last will be referred to as the N-th position command. . That is, when the buffer 11 is full, the chronologically oldest position command is stored as the first position command, and the chronologically newest position command is stored as the Nth position command. .

When the buffer 11 receives the latest position command output from the controller every command cycle, it updates the temporarily stored N position commands. Specifically, the Nth position command to second position command already stored in the buffer 11 are sequentially shifted and rewritten to the (N-1)th position command to first position command, and The latest position command is stored as the Nth position command. That is, the operation of the buffer 11 after being filled is similar to FIFO (First In Fast Out).

The command generating unit 12 sequentially reads N position commands after the tank is full from the buffer 11 in each command period. Further, the command generation unit 12 generates a reference position command for each command cycle based on the N position commands, and outputs the generated reference position command to the motor control unit 13. Here, the reference position command corresponds to a position target value used for position control by the motor control unit 13.

The motor control unit 13 acquires the reference position command generated by the command generation unit 12 as a position target value for each command cycle. Further, the motor control unit 13 acquires a position feedback value from the encoder 3 that detects the position of the motor 2 that is the controlled object. Then, the motor control unit 13 performs feedback control to make the position feedback value match the position target value, thereby controlling the position of the motor 2 that is the controlled object.

The abnormality detection unit 14 detects an abnormal state in which the motor control device 10 cannot normally receive a position command. This abnormal state means an abnormal state on the controller 1 side in which a position command is not normally output from the controller 1, or a communication abnormal state in which a position command normally output from the controller 1 cannot be received normally by the buffer 11.

In other words, the abnormal state detected by the abnormality detection unit 14 means a situation in which the motor control device 10 can function normally, but a normal position command cannot be received on the motor control device 10 side for some reason.

This situation also occurs when a power outage occurs. Even during such a power outage, the motor control device 10 according to the first embodiment uses the position command buffered in the buffer 11 before the power outage if it can use its own surplus accumulated power. It is possible to generate a reference position command and continue operation.

When an abnormal state is detected by the abnormality detection section 14, the information is transmitted to the command generation section 12. Note that the method of generating the reference position command by the command generation unit 12 differs depending on whether an abnormal state is detected or when no abnormal state is detected, and the details will be described later.

The past storage unit 15 sequentially stores reference position commands outputted from the command generation unit 12 to the motor control unit 13 in each command cycle as a past reference position command sequence. The past reference position command sequence stored in the past storage unit 15 is used when performing the evacuation operation by tracing back the trajectory of normal operation and controlling the drive of the motor 2. Details of this evacuation operation will be described later.

Next, a method for generating a reference position command by the command generation unit 12 will be described in detail in three states.
(State 1) Normal operation (State 2) Decelerating after an abnormal condition is detected (State 3) Evacuation operation executed after an abnormal condition is detected and deceleration and stop is completed (State 4) Deceleration of evacuation operation During ~

<(State 1) Method of generating reference position command during normal operation>
During normal operation is an operation in which the motor control device 10 performs position control of the motor 2 based on position commands sequentially output from the controller 1 in a state before an abnormal state is detected.

As described above, in the buffer 11, there are N position commands from the first position command inputted N command cycles ago to the Nth position command stored as the latest position command. It is updated and stored every command cycle. Therefore, during normal operation, the command generation unit 12 extracts the first position command from among the N position commands temporarily stored in the buffer 11, updated every command cycle, according to the FIFO rule.

Then, the command generation unit 12 transmits this first position command to the motor control unit 13 as a reference position command. That is, the command generation unit 12 sequentially replaces the position command output from the controller 1 N command cycles ago with the reference position command every command cycle.

In other words, in the buffer 11 during normal operation, the second to Nth position commands are written before the abnormal state is detected and are not yet sent to the motor control unit 13 as future reference position commands. This means that (N-1) position commands up to the position command are stored. In that sense, the buffer 11 can be said to be a future buffer for the motor control section 13.

<(State 2) How to generate a reference position command during deceleration after an abnormal condition is detected>
In state 1, when an abnormal state is detected during normal operation in which reference position commands are sequentially generated, a transition is made to state 2, and deceleration to a stop is executed.

In the deceleration operation in state 2, normal operation was planned to be followed without immediately stopping the motor 2 and by utilizing the N position commands already stored in the buffer 11 during normal operation. It is characterized by decelerating and stopping along the trajectory. Therefore, a method for generating a reference position command for decelerating and stopping the vehicle along the trajectory that was planned to follow during normal operation will be described below.

FIG. 2 is an explanatory diagram regarding a method for generating a reference position command by the command generation unit 12 when an abnormal state is detected in the first embodiment of the present invention. When an abnormal state is detected in the abnormality detection unit 14, the command generation unit 12 generates a reference position command based on the N position commands that were buffered in the buffer 11 before the abnormal state was detected. do.

At this time, the command generation unit 12 generates a complementary position command by complementing one or more additional position commands between adjacent position commands in the first position command. In FIG. 2, the position commands marked □ correspond to the positions of the four initial plan commands that were buffered in the buffer 11 before the abnormal condition was detected.

More specifically, in the example of FIG. 2, the positions of the initial plan commands are buffered as the following four position commands. Note that the value of the position command is shown as having no unit because it is only necessary to know that the position changes.
First position command: position 20
Second position command: position 21
Third position command: position 22
Fourth position command: position 23

That is, assuming that normal operation continues without any abnormal conditions being detected, the command generation unit 12 generates a command based on the first position command, second position command, third position command, and fourth position command. Then, a reference position command is generated in order for each command cycle. Therefore, in this case, the reference position command changes in the order of position 20, position 21, position 22, and position 23 every command cycle.

On the other hand, in state 2 where an abnormal state is detected, the command generation unit 12 decelerates and stops while moving along the normal operation trajectory of positions 20, 21, 22, and 23. A reference position command is generated as follows. That is, as shown in FIG. 2, the command generation unit 12 generates complementary position commands by complementing one or more additional position commands between adjacent position commands indicated by squares.

The command generation unit 12 can generate a complementary position command according to a preset deceleration rate. In the specific example shown in FIG. 2, the deceleration rate is defined as 1/2^n (n=1, 1, 1, 1, 2, 2, 2, 3, 3, 4),
50%, 50%, 50%, 50%, 25%, 25%, 25%, 12.5%, 12.5%, 6.25%
Complementary position commands are generated according to the deceleration rate.

That is, the command generation unit 12 complements the gap between the first position command: position 20 and the second position command: position 21 with position 20.5, which is a 50% position command. Similarly, the command generation unit 12 complements the gap between the second position command: position 21 and the third position command: position 22 with position 21.5, which is a 50% position command.

As a result, the command generation unit 12, when moving from position 20 to position 22,
position 20
position 20.5
position 21
position 21.5
position 22
Five position commands can be generated as complementary position commands.

When moving from position 20 to position 22, during normal movement, the position command changes to move in two command cycles, but when an abnormality is detected, the position command changes to move in four command cycles. In this case, when moving the same distance, it will take twice as long when an abnormality is detected as compared to normal operation, and the deceleration rate will be 50%.

When moving from position 22 onward, the command generation unit 12 generates three position commands with a deceleration rate of 25%, at positions 22 and 25.
position 22.5
position 22.75
can be generated as a complementary position command.

Furthermore, when moving from position 22.75 onward, the command generation unit 12 generates two position commands with a deceleration rate of 12.5% at position 22.875.
position 23
can be generated as a complementary position command.

Similarly, the command generation unit 12 can set the deceleration rate to 6.25% and generate a position command used for movement from position 23 onward as a complementary position command. In FIG. 2, the plot indicated by ● corresponds to the position of the deceleration command generated by the command generation unit 12 as the complementary position command.

The command generating unit 12 outputs a complementary position command generated by a complementary process according to a preset deceleration rate to the motor control unit 13 as a reference position command every command cycle. Specifically, when moving from position 20 to position 23, for each command cycle,
position 20
Position 20.5 (equivalent to 50% deceleration rate)
Position 21 (equivalent to 50% deceleration rate)
Position 21.5 (equivalent to 50% deceleration rate)
Position 22 (equivalent to 50% deceleration rate)
Position 22.25 (equivalent to 25% deceleration rate)
Position 22.5 (equivalent to 25% deceleration rate)
Position 22.75 (equivalent to 25% deceleration rate)
Position 22.875 (equivalent to deceleration rate of 12.5%)
Position 23 (equivalent to deceleration rate of 12.5%)
Position 23.0625 (equivalent to deceleration rate of 6.25%)
The reference position commands are sequentially given to the motor control section 13. As a result, the motor 2 decelerates and stops in accordance with the transition of the position command specified by the complementary position command.

As described above, the deceleration and stop processing according to the first embodiment generates a complementary position command by performing a complementary process based on the N position commands already stored in the buffer 11 during normal operation. It is characterized by As a result, by driving and controlling the motor 2 using the generated supplementary position command, it is possible to decelerate and stop the motor 2 along the trajectory that was planned to follow during normal operation.

<(State 3) Method for generating a reference position command in the evacuation operation executed after an abnormal condition is detected and deceleration and stop is completed>
After the motor 2 is stopped by the deceleration and stop processing in (state 2) described above, the evacuation operation is executed. When performing the evacuation operation, the past reference position command stored in the past storage section 15 is used.

In the past storage section 15, reference position commands outputted from the command generation section 12 to the motor control section 13 for each command period are sequentially stored as a past reference position command sequence. That is, in (state 1) and (state 2) described above, the reference position commands that are sequentially output from the command generation unit 12 to the motor control unit 13 for each command cycle are stored in chronological order as a past reference position command sequence. ing.

Therefore, the command generation unit 12 sequentially extracts past position commands from the past reference position command sequence, starting from the most recently stored position command, and generates the reference position command, thereby decelerating the command. It is possible to perform an evacuation operation that traces the trajectory during normal and normal operation. Here, the command generation unit 12 can execute the retracting operation while accelerating the motor 2 by retrieving the reference position commands stored at the time of deceleration and stop in the reverse order and generating the reference position commands.

Further, the command generation unit 12 can execute the evacuation operation while moving the motor 2 at a constant speed by retrieving the reference position commands stored during normal operation in reverse order and generating the reference position commands.

Further, the command generation unit 12 specifies one position in the past reference position command sequence as the final target position to be evacuated, thereby stopping the motor 2 at the final target position and ending the retracting operation. be able to.

<(State 4) Method for generating reference position command during deceleration and stop of evacuation operation>
In addition, when stopping the motor 2 at the final target position, the command generation unit 12 performs the complementary process used for decelerating and stopping in (state 2), so that the motor 2 can also be stopped at the final target position. It can be decelerated and stopped.

FIG. 3 shows the speed and position when processing is performed in the order of (state 1), (state 2), (state 3), and (state 4) in the motor control device according to the first embodiment of the present invention. FIG. FIG. 3 illustrates a state in which a failure state is detected at time T1, completion of deceleration and stop is detected at time T2, and deceleration of the evacuation operation is started at time T3.

That is, in FIG. 3, the time period before time T1 corresponds to (state 1) during normal operation, and the time period from time T1 to time T2 corresponds to (state 2) during deceleration. The time period from time T2 to time T3 corresponds to the evacuation operation (state 3), and the time period after T3 corresponds to the deceleration of the evacuation operation (state 4). Moreover, in FIG. 3, the upper waveform shows the time transition of velocity, and the lower waveform shows the time transition of position. Furthermore, regarding the time transition of the position, the waveform of the prior art when an immediate stop is performed without deceleration and an evacuation operation is performed at time T1 when a failure state is detected is also shown as a broken line.

As is clear from FIG. 3, in the motor control device according to Embodiment 1, after a failure condition is detected at time T1, the motor control device does not immediately stop the operation, but instead follows the trajectory that was planned for normal operation. This is how it decelerates and stops. Furthermore, after time T2 when the deceleration and stop is completed, the evacuation operation is performed along the route tracing back the previous trajectory.

Therefore, by performing a smooth deceleration and stop, it is possible to suppress the shock to the machine that would be caused by an immediate stop. Furthermore, in the deceleration stop and retreat operations, it is possible to move along the trajectory during normal operation, so damage to the workpiece etc. can be suppressed.

Next, detailed operations of the command generation unit 12 will be explained in chronological order by dividing them into the following four operations along with a specific configuration example.
Action 1: Action during normal operation (state 1) Action 2: Action during deceleration (state 2) Action 3: Action during acceleration and constant speed movement during evacuation operation (state 3) Action 4: Action during (state 4) ) movement during deceleration during evacuation movement

<Operation 1: Operation during normal operation (state 1)>
FIG. 4 is a functional block diagram showing a state in which the motor control device 10 according to Embodiment 1 of the present invention executes operation 1. The command generation unit 12 in FIG. 4 includes a deceleration and stop command generation unit 12a, changeover switches 12b, 12c, and 12d.

Further, A in FIG. 4 is a signal indicating a state in which an abnormality is detected in the abnormality detection unit 14, B is a signal indicating a state in which deceleration and stop in (state 2) is completed, and C is a signal indicating a state in which deceleration and stop in (state 3) is completed. ) is a signal indicating the start of deceleration and stop in the evacuation operation. The states of the changeover switches 12b, 12c, and 12d are changed according to the rise of the signals A, B, and C. The route established by operation 1 is shown as a thick line in FIG.

Furthermore, in FIG. 4, in addition to the configuration shown in FIG. , further provided within the motor control device 10.

In operation 1, no abnormal state is detected by the abnormality detection unit 14. That is, this corresponds to a case where signal A, signal B, and signal C are all invalid. In this case, the command generation unit 12 outputs the first position command read from the buffer 11 for each command cycle as the reference position command. Further, the reference position commands at that time are sequentially stored in the past storage section 15.

FIG. 5 is a diagram showing temporal changes in the speed waveform and position waveform when the motor control device 10 according to the first embodiment of the present invention executes the operation 1. In FIG. 5, compared to FIG. 3, a portion corresponding to operation 1 is shown surrounded by a dashed-dotted frame.

<Operation 2: Operation during deceleration in (state 2)>
FIG. 6 is a functional block diagram showing a state in which the motor control device 10 according to Embodiment 1 of the present invention executes operation 2. The basic configuration of FIG. 6 is the same as that of FIG. 4, and the connection states of the changeover switches 12b, 12c, and 12d are different between FIG. 4 and FIG. 6. The route established by operation 2 is shown as a thick line in FIG. That is, in operation 2, since the signal A rises, the switch 12c changes from the state shown in FIG. 4 to the state shown in FIG. 6.

In operation 2, the deceleration and stop command generation unit 12a in the command generation unit 12 generates a complementary position command by performing a complementary process based on the N position commands already stored in the buffer 11 during normal operation. generate.

Further, the deceleration and stop command generation unit 12a outputs the generated complementary position command as a reference position command every command cycle. Further, the reference position commands at that time are sequentially stored in the past storage section 15.

FIG. 7 is a diagram showing temporal changes in the speed waveform and position waveform when the motor control device 10 according to Embodiment 1 of the present invention executes operation 2. In FIG. 7, a portion corresponding to operation 2 is shown surrounded by a dashed-dotted line frame, as compared to FIG. 3 above.

<Operation 3: Operation during acceleration and constant speed movement during evacuation operation (state 3)>
FIG. 8 is a functional block diagram showing a state in which the motor control device 10 according to Embodiment 1 of the present invention executes operation 3. The basic configuration of FIG. 8 is the same as that of FIG. 4, and the connection states of the changeover switches 12b, 12c, and 12d are different between FIG. 6 and FIG. 8. The route established by operation 3 is shown as a thick line in FIG. That is, in operation 3, since the signal B rises, each of the switches 12b, 12c, and 12d switches from the state of FIG. 6 to the state of FIG. 8.

In operation 3, the command generation unit 12 generates the most recently stored position command for each command cycle from among the past reference position command sequences stored in the past storage unit 15 while performing operation 1 and operation 2. From then on, past reference position commands are sequentially taken out as reference position commands are outputted as reference position commands.

Note that upon completion of the deceleration and stop in (state 2), the changeover switch 12d becomes an open state, and the reference position command in operation 3 is not stored in the past storage unit 15.

FIG. 9 is a diagram showing temporal changes in the speed waveform and position waveform when the motor control device 10 according to Embodiment 1 of the present invention executes operation 3. In FIG. 9, compared to FIG. 3, a portion corresponding to operation 3 is shown surrounded by a dashed-dotted frame. That is, in operation 3, the evacuation operation is performed by accelerated movement and constant speed movement.

<Operation 4: Operation during deceleration in the evacuation operation of (state 4)>
FIG. 10 is a functional block diagram showing a state in which the motor control device 10 according to Embodiment 1 of the present invention executes operation 4. The basic configuration of FIG. 10 is the same as that of FIG. 4, and the connection states of the changeover switches 12b, 12c, and 12d are different between FIG. 8 and FIG. 10. The route established by operation 4 is shown as a thick line in FIG. That is, in operation 4, since the signal C rises, the switch 12c changes from the state shown in FIG. 8 to the state shown in FIG.

In operation 4, the deceleration and stop command generation unit 12a in the command generation unit 12 determines the final target position based on the past reference position command sequence stored in the past storage unit 15 while performing operation 1 and operation 2. When stopping the motor 2, the complementary processing used for decelerating and stopping in operation 2 is performed and output as a reference position command.

Note that when the deceleration and stop of (state 2) is completed, the changeover switch 12d remains in the open state, and the reference position command in operation 4 is not stored in the past storage unit 15.

FIG. 11 is a diagram showing temporal changes in the speed waveform and position waveform when the motor control device 10 according to Embodiment 1 of the present invention executes operation 4. In FIG. 11, compared to FIG. 3, a portion corresponding to operation 4 is shown surrounded by a dashed-dotted frame. That is, in operation 4, the deceleration and stop processing is executed at the end of the evacuation operation.

As described above, the motor control device according to Embodiment 1 can decelerate and stop along the trajectory of normal operation when an abnormality occurs. Furthermore, when an evacuation operation is required, the trajectory of deceleration and stop and the trajectory of normal operation can be traced back to a desired position and finally decelerated and stopped.

Embodiment 2.
In the first embodiment described above, the case where one motor 2 is drive-controlled as shown in FIG. 1 has been described in detail. However, the motor control device 10 according to the present invention is also applicable to controlling a plurality of motors having two or more axes. Therefore, in the second embodiment, a case where the motor control device 10 is applied to two motors will be described in detail.

FIG. 12 is a system configuration diagram including a motor control device according to Embodiment 2 of the present invention. The motor control device 10 according to the second embodiment controls the position of two motors 2 (1) and 2 (2) based on individual position commands for two axes from one controller 1. . The motor control device 10 includes a buffer 11 (1), a command generation section 12 (1), a motor control section 13 (1), and a past storage section 15 (1) for the first motor 2 (1). ing.

The motor control device 10 also includes a buffer 11 (2), a command generation section 12 (2), a motor control section 13 (2), and a past storage section 15 (2) for the second motor 2 (2). It is equipped with Further, the motor control device 10 includes one abnormality detection unit 14 common to the two motors 2(1) and 2(2).

According to such a configuration, when the abnormality detection unit 14 detects an abnormal state in which the motor control device 10 side cannot normally receive a position command, the motor control device 10 detects that the two-axis motor 2 (1), 2(2), operations 1 to 4 described in the first embodiment can be executed in chronological order. That is, the two control systems corresponding to the two motors 2(1) and 2(2) can be synchronized to execute each process of operations 1 to 4.

FIG. 13 shows the position transition when an abnormal state is detected while the two-axis motor is performing circular motion and operations 1 to 4 are executed in the motor control device according to the second embodiment of the present invention. FIG.

In FIG. 13, the positions for each command cycle are plotted as the state transitions into the following eight states.
[1] During normal operation [2] When abnormality is detected [3] During deceleration [4] When stopped [5] During evacuation operation (including acceleration)
[6] At the start of deceleration during evacuation operation [7] When stopping during evacuation operation

As described above, the motor control device according to the second embodiment can decelerate and stop the motors having two or more axes along the trajectory of normal operation when an abnormality occurs. Furthermore, if an evacuation operation is required, the deceleration and stop trajectory and the trajectory during normal operation can be traced back to a desired position, and finally the deceleration and stop can be performed.

Note that in the first and second embodiments described above, deceleration and stop are performed by executing complement processing according to a preset deceleration rate for the N position commands accumulated in the buffer 11 before the occurrence of a failure. It has been realized. In this case, it is also possible to perform deceleration processing according to a deceleration rate depending on the level of failure. That is, by applying a preset appropriate deceleration rate depending on the degree of urgency to stop the motor 2, it is possible to bring about an emergency stop that is close to an immediate stop.

1 controller, 2 motor, 3 encoder, 10 motor control device, 11 buffer, 12 command generation section, 13 motor control section, 14 abnormality detection section, 15 past storage section.

Claims (3)

The position commands output from the controller are sequentially buffered for each command cycle, and N position commands from the first buffered position command to the Nth position command last buffered are stored. A buffer for temporary storage,
a command generation unit that generates a reference position command for each command cycle based on the N position commands temporarily stored in the buffer;
a motor control unit that controls the position of a motor to be controlled by receiving the reference position command generated by the command generation unit at each command cycle;
and an abnormality detection unit that detects an abnormal state in which the position command is not normally output from the controller,
The command generation unit includes:
If the abnormal state is not detected in the abnormality detection section, the first position command outputted from the controller N command cycles ago and temporarily stored in the buffer is set as the reference position command,
When the abnormal state is detected in the abnormality detection section, the N position commands are processed by utilizing the N position commands that were buffered in the buffer before the abnormal state was detected. A complementing process is executed to generate a supplementary position command by supplementing one or more additional position commands between adjacent position commands, and the supplementary position command is used as the reference position command for each command period, and normal operation is performed. A motor control device that decelerates and stops the motor along a planned trajectory . further comprising a past storage unit that sequentially stores the reference position commands outputted from the command generation unit to the motor control unit in each command cycle as a past reference position command sequence,
The command generation unit includes:
After the abnormal state is detected in the abnormality detection unit and the motor decelerates to a stop, command cycles are sequentially determined from the past reference position command sequence sequentially stored in the past storage unit, starting from the latest position command in chronological order. The motor control device according to claim 1, wherein the motor control device executes an evacuation operation tracing back a trajectory during deceleration and normal operation by extracting the reference position command at each time and generating the reference position command. When the motor to be controlled is configured as a plurality of motors, and the position of each of the plurality of motors is controlled based on individual position commands output from the controller,
It has a plurality of control systems including the buffer, the command generation section, the motor control section, and the past storage section corresponding to each of the plurality of motors,
When the abnormality detection unit provided in common to the plurality of motors detects a failure state, the plurality of control systems synchronize and execute the complementary processing to decelerate the plurality of motors. The motor control device according to claim 1 or 2, wherein the motor control device stops the motor.

Images