JP2014119904A - Control device, control program, and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel control device, a control program and a control method thereof which are capable of reducing the influence of a delay time occurring in periodic input processing or control processing.SOLUTION: The control device includes: an input unit which acquires measurement information indicative of a state value of an object, from a measurement instrument at intervals of a preliminarily determined period; and an arithmetic processing unit which executes control operation based on the measurement information at intervals of a preliminarily determined arithmetic period and outputs a command value according to the execution result. The arithmetic processing unit includes: shift means which generates a preliminarily set phase or time delay on a control output generated from the measurement information; calculation means which calculates a compensation amount from the difference between the measurement information and the control output on which the delay is generated by the shift means; and compensation means which compensates the measurement information by the compensation amount calculated by the calculation means.

Description

  The present invention relates to a control device suitable for a control system including a delay time that can be estimated in advance, a control program thereof, and a control method thereof.

  A control device such as a programmable logic controller (hereinafter referred to as “PLC”) is used for controlling machines and equipment. As an example of such an object to be controlled by the PLC, there is a control application interlocked with a main shaft and a slave shaft. More specifically, the spindle / slave-linked control application uses the measurement information obtained by measuring the state value (rotation speed and displacement) of the object with the measuring device (spindle) to process the object. This is an application that controls (slave shaft). In such a control application, there is a problem that a delay occurs until information measured on the main shaft is processed and transmitted to the slave shaft. Therefore, a method for reducing the influence of such a delay has been proposed as follows.

  Japanese Patent Application Laid-Open No. 08-126375 (Patent Document 1) discloses a synchronous control device in which a sub shaft motor can follow a main shaft motor without delay. More specifically, in a device for synchronously driving the main shaft motor and the sub shaft motor, a foreseeing controller that is controlled so that the rotational position of the motor predicted from the dynamic characteristic model of the sub shaft motor matches the future target position command. And a means for calculating a predicted value of the future position of the spindle motor, and a means for obtaining a future target position command of the dependent axis motor as a function of the predicted future position of the spindle motor and inputting it to the foreseeing controller. Is disclosed.

  Japanese Patent Application Laid-Open No. 09-289788 (Patent Document 2) realizes highly accurate synchronization control, and there is little deterioration in synchronization accuracy even when there is a delay in position command input or spindle position detection. A synchronous control device is disclosed. More specifically, a synchronous control device that drives the dependent shaft motor in synchronization with the main shaft motor, including the prediction device 1, the main shaft device 2, and the dependent shaft device 3, is disclosed. The prediction device 1 outputs a spindle position command increment value input to a plurality of past points up to the present, and a spindle position command increment value input before M-1 sampling among the stored values. Means for storing the spindle position increment values inputted to a plurality of past points up to the present, a dynamic characteristic model of the spindle device including d sampling delay, and the stored spindle position command increment value And a calculator 9 for obtaining predicted values of a plurality of spindle position increment values up to several sampling destinations based on the spindle position increment value, and a plurality of dependent axis future positions from the obtained predicted values of the plurality of spindle position increment values. A configuration including a converter 10 for obtaining a command is disclosed.

  Furthermore, Japanese Patent Laid-Open No. 10-174478 (Patent Document 3) discloses a synchronous control device that does not deteriorate the synchronization accuracy even when the dynamic characteristics of the main shaft are different between forward rotation and reverse rotation. Specifically, it is a synchronous control device that drives a subordinate motor in synchronization with a main shaft motor, and includes a signal obtained by multiplying an increment value of a main shaft position between sampling periods or a predicted value thereof by a multiplier K1, and a main shaft position command increment. In a synchronous control device provided with a fine adjustment device 19 for inputting a signal obtained by adding a signal multiplied by a multiplier K2 to a control device for a dependent axis motor as a fine adjustment signal for synchronization deviation, two types of multipliers K1 are stored, and the spindle A configuration having means for switching depending on whether the position increment value is positive or negative is disclosed.

Japanese Patent Laid-Open No. 08-126375 JP 09-289788 A Japanese Patent Laid-Open No. 10-174478

  In the above-described Patent Documents 1 to 3, it is necessary to adjust a model, a plurality of parameters, and the like according to a target control system. When actually applied, adjustment takes time.

  An object of the present invention is to provide a novel control device, control program, and control method thereof that can reduce the influence of delay time that occurs in periodic input processing and control processing.

  A control device according to an aspect of the present invention includes an input unit that acquires measurement information indicating a state value of an object for each predetermined cycle from the measurement device, and a control calculation based on the measurement information for each predetermined calculation cycle. And an arithmetic processing unit that outputs a command value according to the execution result. The arithmetic processing unit compensates for the difference between the shift means that causes a preset phase or time delay with respect to the control output generated from the measurement information and the control information that causes the delay due to the measurement information and the shift means. Calculation means for calculating the quantity, and compensation means for compensating the measurement information with the compensation amount calculated by the calculation means.

  Preferably, the phase or time set in the shift means is related to an output delay of measurement information from the measurement device to the input unit.

  Preferably, the phase or time set in the shift means is associated with the calculation cycle of the calculation processing unit.

  Preferably, the arithmetic processing unit includes a network for transmitting data between the measuring device and the actuator that receives the command value, and the phase or time set in the shift means is the transmission delay time in the network. Associated.

  Preferably, the calculation means includes an element for making the dimensions coincide between the measurement information and the control output delayed by the shift means.

  According to another aspect of the present invention, an input unit that acquires measurement information indicating a state value of an object for each predetermined period from the measurement device, and a control calculation based on the measurement information is performed for each predetermined calculation period. And a control program that is executed by a computer having an arithmetic processing unit that outputs a command value according to the execution result. The control program causes the computer to generate a compensation amount based on the difference between the step of causing a preset phase or time delay with respect to the control output generated from the measurement information and the measurement information and the control output causing the delay. And a step of compensating the measurement information with the calculated compensation amount.

  According to still another aspect of the present invention, an input unit that acquires measurement information indicating a state value of an object for each predetermined cycle from the measurement device, and a predetermined calculation cycle for a control calculation based on the measurement information A control method is provided that is executed by a computer that includes an arithmetic processing unit that is executed every time and outputs a command value according to the execution result. The control method calculates a compensation amount from a difference between a step of causing a preset phase or time delay with respect to a control output generated from measurement information, and a difference between the measurement information and the control output causing the delay. And compensating the measurement information with the calculated compensation amount.

  According to the present invention, it is possible to reduce the influence of delay time that occurs in periodic input processing and control processing.

It is a schematic diagram which shows the structure of the control system which concerns on this Embodiment. It is a schematic diagram for demonstrating a spindle / slave interlock in the control system which concerns on this Embodiment. It is a figure for demonstrating the influence of the delay time in the control system which concerns on this Embodiment. It is a schematic diagram which shows the control structure mounted in the control apparatus which concerns on this Embodiment. It is a schematic diagram which shows the structure of another control system which concerns on this Embodiment.

  Embodiments of the present invention will be described in detail with reference to the drawings. In addition, about the same or equivalent part in a figure, the same code | symbol is attached | subjected and the description is not repeated.

<A. System configuration>
As an embodiment of the present invention, a spindle / slave-linked control application that measures a moving object (hereinafter referred to as “work”) and performs processing at a predetermined position will be considered.

  FIG. 1 is a schematic diagram showing a configuration of a control system 100 according to the present embodiment. Referring to FIG. 1, control system 100 according to the present embodiment includes transport motors 112 and 114 for transporting work W such as an iron plate, and a rotary cutter for cutting work W.

  The amount of movement (or conveyance speed) of the workpiece W is measured by a measuring roll associated with the movement of the workpiece W, which is a measuring device. As this measuring roll, an encoder 140 arranged so that its rotating shaft is in contact with the back surface of the workpiece W is used. That is, the amount of movement of the workpiece W is calculated based on the detection signal (pulse signal) from the encoder 140, and the workpiece W is cut at a predetermined interval.

  The workpiece W is cut by a pair of rotary cutters 102 and 104 arranged in a direction orthogonal to the conveying direction. More specifically, when the rotary cutter 102 is driven by the servo motor 110, the rotary cutters 102 and 104 rotate synchronously, and the workpiece W is cut with a blade formed on a part of the circumference thereof. The servo motor 110 is driven to rotate by being supplied with a signal (typically a pulse signal) related to the drive from the servo driver 40.

  In the example shown in FIG. 1, the encoder 140 is also referred to as a main shaft, and the servo motor 110 that is driven by receiving information from the main shaft is also referred to as a slave shaft.

  The measurement of the movement amount of the workpiece W and the cutting of the workpiece W are controlled by the control device 1. Next, details of the control device 1 will be described.

<B. Configuration of control device>
The control device 1 shown in FIG. 1 is typically realized by a programmable logic controller (hereinafter referred to as “PLC”) or the like. Of course, you may mount not using PLC but using a personal computer (PC) and various arithmetic processing units.

  The control apparatus 1 communicates with a field device such as a CPU (Central Processing Unit) unit 10 that executes main arithmetic processing, a pulse counter 20 that detects and counts pulse signals output from the encoder 140, and a servo driver 40. Fieldbus interface unit 30 (also referred to as “fieldbus I / F”) for performing.

The CPU unit 10 includes a microprocessor and a RAM (Random) as main components.
It includes a volatile memory such as an access memory and a non-volatile memory such as a hard disk drive (HDD) and a read only memory (ROM). Typically, in the control device 1, processing described later is realized by the CPU unit 10 executing a program. However, all or part of the processing realized by the program may be realized by dedicated hardware.

Field networks include EtherCAT (registered trademark) and Profinet.
Various industrial Ethernet (registered trademark) such as IRT, MECHATROLINK (registered trademark) -III, Powerlink, SERCOS (registered trademark) -III, and CIP Motion can be used. Alternatively, a proprietary network such as DeviceNet or CompoNet / IP (registered trademark) may be used. That is, in the control device 1, a network for transmitting data is arranged between the encoder 140 that is a measuring device and the actuator that receives the command value.

  The control device 1 may include an input / output unit and a special unit (not shown). These units are configured to exchange data with each other via a PLC system bus (not shown).

  In the configuration example shown in FIG. 1, the information may be transmitted to the encoder 140 through a network such as a fieldbus. That is, at least one of the pulse counter 20 that is an input unit and the servo driver 40 that is a drive unit may exchange information through a network.

  The pulse counter 20 illustrated in FIG. 1 corresponds to an input unit that obtains measurement information indicating a state value of an object (work W) from the encoder 140 serving as a measurement device for each cycle. The CPU unit 10 corresponds to an arithmetic processing unit that executes a control calculation based on measurement information for each predetermined calculation cycle and outputs a command value corresponding to the execution result.

  The control device 1 according to the present embodiment can further improve the cutting accuracy of the workpiece W by employing processing logic as described later. Details of this processing logic will be described below.

<C. Delay time and compensation>
First, the relationship between the detection value (main shaft position / count value) by the encoder 140 that is the main shaft and the rotational motion of the servo motor 110 that is the sub shaft will be described. The rotary cutter shown in FIG. 1 needs to appropriately control the position of the blade according to the movement of the workpiece W. In other words, by appropriately controlling the rotation angle of the servo motor 110, a kind of cam motion is realized.

FIG. 2 is a schematic diagram for explaining the interlocking of the main shaft and the slave shaft in the control system 100 according to the present embodiment. As shown in FIG. 2, the slave target angle (the angles of the rotary cutters 102 and 104) is determined according to a predetermined relationship rather than linear with respect to a change in the spindle position indicating the movement amount of the workpiece W. Typically, the relationship between the main shaft and the slave shaft is realized by a cam table described later. That is, the relationship between the spindle and the slave shaft shown in FIG. 2 is defined as a cam table, and the angle of the rotary cutters 102 and 104 is determined by referring to this cam table according to the number of pulses counted by the pulse counter 20. Are sequentially calculated.

  In order to make the cut surface with respect to the workpiece W more preferable, both the slave shaft target angle [rad] and the slave shaft target angular velocity [rad / s] which is a differential value thereof are considered. In terms of the slave target angular velocity, the slave target angular velocity is limited to a constant value (typically a value corresponding to the conveyance speed of the workpiece W) from the start position of the cutting operation to the distance p1. Thereafter, the angular velocities of the rotary cutters 102 and 104 are increased so as to maximize at a distance p2 from the starting position of the cutting operation. Thereafter, at the position of the distance p3 from the start position of the cutting operation, the slave target angular velocity is again limited to a constant value (typically a value corresponding to the conveyance speed of the workpiece W). Then, the cutting operation is completed at a position of distance p4 from the starting position of the cutting operation.

  Next, the influence of the delay time in the main / slave interlock will be described. FIG. 3 is a diagram for explaining the influence of the delay time in the control system 100 according to the present embodiment.

  In the control system 100 shown in FIG. 1, the state value related to the conveyance of the workpiece W is measured by the encoder 140. The encoder 140 measures the position (spindle position) at each time point related to the movement of the workpiece W, which is the object, as the state value. However, the state value is not limited to the position (displacement), but includes speed (or angular velocity), acceleration, jerk, and the like.

  When the measurement information by the encoder 140 is transmitted via a field network or the like, a delay time (dead time) due to the transmission is unavoidable. Further, the pulse counter 20 counts the detection signal (pulse signal) from the encoder 140, and the CPU unit 10 refers to the count value to calculate the slave shaft target angle. Furthermore, a delay time required for the calculated slave shaft target angle to be transmitted to the servo driver 40 via the field bus is also required.

  Due to these delay times (dead time), the timing at which the rotary cutters 102 and 104 as the driven shafts actually start operating is delayed. Specifically, as shown in FIG. 4, since the timing at which the slave target angle is actually effective is delayed with respect to the spindle position, the delay becomes a cut dimension error. That is, originally, the cutting operation should be completed at the position of the distance p4 from the starting position of the cutting operation, but in reality, the cutting operation is completed at the position of the distance p4 '.

  As shown in FIG. 3, an error in cut dimensions may occur due to a position detection delay or a CPU calculation delay. In the present embodiment, by correcting such a delay time, the influence of the occurrence of an error in cut dimensions is avoided, and the rotary cutter is controlled with higher accuracy.

<D. Control structure>
Next, a control structure implemented in the control device 1 of the control system 100 shown in FIG. 1 will be described.

  FIG. 4 is a schematic diagram showing a control structure implemented in the control device 1 according to the present embodiment. The control structure shown in FIG. 4 is realized by the CPU unit 10 executing a program. Basically, the CPU unit 10 executes calculation processing at a predetermined calculation cycle (for example, 10 msec). Therefore, the calculation related to the control structure shown in FIG. 4 is also repeatedly executed at a predetermined calculation cycle.

  Referring to FIG. 4, control device 1 includes an amplification element 12, an addition element 13, a filter element 14, a subtraction element 15, an integration element 16, and a phase shift filter 17 as its control structure. The control structure shown in FIG. 4 is a position control system.

  In the control device 1, the pulse counter 20 counts the pulse signal from the encoder 140. This count value corresponds to the spindle position of the workpiece W, and this spindle position (count value) is read by the CPU unit 10. In the control device 1, control is performed based on the spindle position of the workpiece W.

  The spindle position of the workpiece W is smoothed by the filter element 14. The filter element 14 is used to remove the influence such as noise generated in the pulse signal input to the pulse counter 20. The filter element 14 corresponds to a smoothing unit that performs a smoothing process on the pulse signal from the encoder 140 that is measurement information.

  The smoothed position output from the filter element 14 corresponds to the estimated position of the workpiece W. The output from the filter element 14 is given to the target value calculation unit 21. The target value calculation unit 21 calculates a target value (target angular velocity of the servo motor 110 that drives the rotary cutters 102 and 104) to be given to the servo driver 40 with reference to the cam table 21a that defines the characteristics as shown in FIG. Is done. The calculated target value is output to the servo driver 40.

  The phase shift filter 17 is arranged in front of the integration element 16. The phase shift filter 17 delays (shifts) the estimated position of the workpiece W output from the filter element 14 by a predetermined time (phase), and outputs the result to the integration element 16. . That is, the phase shift filter 17 corresponds to a shift unit that causes a preset phase or time delay with respect to the control output generated from the measurement information. Here, the integration element 16 is an element for making the dimensions coincide between the measurement information and the control output delayed by the phase shift filter 17. More specifically, the integration element 16 integrates the velocity information output from the phase shift filter 17 and adjusts the value to the same dimension as the spindle position.

  More specifically, the phase shift filter 17 compensates for a delay time caused by a transmission delay or a calculation cycle. Basically, after estimating these delay times, the phase shift filter 17 has a time comparable to that. Based on this, the delay time (phase) is determined. For example, by delaying the estimated position of the workpiece W by a predetermined time (phase) and feeding back, the estimated position of the workpiece W is compensated in the direction in which the phase is advanced. In the phase shift filter 17, it is preferable that the time for shifting the phase is substantially the same as the delay time in the field network (and the time required for the command value generation process and the output process in the CPU unit 10). It is preferable that the phase shifting time (phase shift time) in the phase shift filter 17 can be arbitrarily set or changed.

  Thus, it is preferable that the shift phase or shift time set in the phase shift filter 17 serving as the shift means is associated with the output delay of the measurement information from the measurement device (encoder 140) to the input unit (pulse counter 20). . Further, the shift phase or shift time set in the phase shift filter 17 serving as the shift means is associated with the calculation cycle of the calculation processing unit (CPU unit 10). Further, the shift phase or shift time set in the phase shift filter 17 serving as the shift means is related to the transmission delay time in a network such as a field network.

The phase shift filter 17 is typically a first-order lag filter. The phase of the transport position is shifted by a predetermined time (delay time) by the phase shift filter 17, and as a result, the processing is actually executed by the system for calculating the observer correction value as described later. The phase of the spindle position can be advanced.

  The subtraction element 15 calculates the difference between the spindle position corresponding to the count value by the pulse counter 20 and the estimated position delayed in time (phase). That is, the subtraction element 15 corresponds to a calculation unit that calculates a compensation amount from a difference between the measurement information and a control output that is delayed by the phase shift filter 17 that is a shift unit.

  The addition element 13 adds the compensation amount output from the subtraction element 15 and whose amplitude is adjusted in the amplification element 12 to the spindle position output from the pulse counter 20. That is, the addition element 13 corresponds to a compensation unit that compensates the measurement information with the compensation amount calculated by the subtraction element 15 that is a calculation unit.

  By adopting the observer control as described above, it is possible to reduce the influence due to the delay time generated in the periodic input processing and control processing.

<E. Another application>
The present invention can be applied to the following control system 200 in addition to the control system 100 described above.

  FIG. 5 is a schematic diagram showing a configuration of another control system 200 according to the present embodiment. Referring to FIG. 5, control system 200 assumes a moving object (a glass substrate of a solar panel or the like as work W. This control system 200 irradiates the work W with laser light. A predetermined wiring pattern is formed, etc. The distance between the light source of the laser beam and the irradiation position of the workpiece W needs to be maintained at a predetermined value, so that the distance to the workpiece W is optically measured. In addition to the measurement, the laser light source is sequentially moved in the vertical direction of the workpiece W based on the measured distance.

  More specifically, the laser light source 240 and the measurement camera 250 are disposed on the same substrate 220, and this substrate 220 is moved vertically by the servo motor 230, that is, perpendicular to the surface of the workpiece W. Moved to. By this movement, the distance between the substrate 220 and the laser light source 240 is maintained at a predetermined value. It is assumed that the surface of the workpiece W has irregularities that cannot be ignored.

  The surface of the workpiece W is imaged by the measurement camera 250, and the distance to the surface of the glass substrate is calculated by the glass surface distance calculation logic 260 from the image obtained by this imaging and the optical constant (focus position, etc.) at that time. The This distance is updated every predetermined period. In other words, the distance measurement by the measurement camera 250 and the glass surface distance calculation logic 260 has an estimated delay time (dead time).

  The servo motor 230 is rotationally driven by being supplied with a signal (typically a pulse signal) related to the driving from the servo driver 40.

  The control device 1A includes a CPU (Central Processing Unit) unit 10 that executes main arithmetic processing, an AD (Analog to Digital) unit 50 that acquires distances output from the measurement camera 250 and the glass surface distance calculation logic 260, And a fieldbus interface unit 30 for communicating with field devices such as the servo driver 40.

  Since other basic configurations and control structures are the same as those of control system 100 shown in FIG. 1, detailed description will not be repeated.

<F. Advantage>
According to the control device according to the present embodiment, it is possible to reduce the influence due to the delay time generated in the periodic input processing and control processing.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Control apparatus, 2 spindle apparatus, 10 CPU unit, 12 Amplification element, 13 Addition element, 14 Filter element, 15 Subtraction element, 16 Integration element, 17 Phase shift filter, 19 Fine adjustment apparatus, 20 Pulse counter, 21 Target value calculation Part, 21a cam table, 30 fieldbus interface unit, 40 servo driver, 100, 200 control system, 102, 104 rotary cutter, 110, 230 servo motor, 112, 114 transport motor, 140 encoder, 220 substrate, 240 laser light source, 250 measurement camera, 260 glass surface distance calculation logic.

Claims (7)

An input unit that obtains measurement information indicating a state value of the object from the measurement device at predetermined intervals;
A control calculation based on the measurement information is executed for each predetermined calculation cycle, and a calculation processing unit that outputs a command value according to the execution result is provided.
The arithmetic processing unit includes:
Shift means for causing a preset phase or time delay with respect to the control output generated from the measurement information;
Calculation means for calculating a compensation amount from a difference between the measurement information and a control output caused by the shift means;
Compensating means for compensating the measurement information with a compensation amount calculated by the calculating means.   The control device according to claim 1, wherein the phase or time set in the shift means is associated with an output delay of the measurement information from the measurement device to the input unit.   The control device according to claim 1, wherein the phase or time set in the shift unit is associated with a calculation cycle of the calculation processing unit. In the arithmetic processing unit, a network for transmitting data is arranged between the measuring device and the actuator that receives the command value,
The control device according to claim 1, wherein the phase or time set in the shift unit is associated with a transmission delay time in the network.   5. The control device according to claim 1, wherein the calculation unit includes an element for matching a dimension between the measurement information and a control output in which a delay is caused by the shift unit. An input unit that obtains measurement information indicating the state value of the object from the measurement device at predetermined intervals, and a control calculation based on the measurement information is executed at predetermined calculation intervals, and depending on the execution result A control program executed by a computer including an arithmetic processing unit for outputting a command value, wherein the control program is
Producing a preset phase or time delay with respect to the control output generated from the measurement information;
Calculating a compensation amount from a difference between the measurement information and the control output causing the delay;
A control program for executing the step of compensating the measurement information with the calculated compensation amount. An input unit that obtains measurement information indicating the state value of the object from the measurement device at predetermined intervals, and a control calculation based on the measurement information is executed at predetermined calculation intervals, and depending on the execution result A control method executed by a computer including an arithmetic processing unit for outputting a command value,
Producing a preset phase or time delay with respect to the control output generated from the measurement information;
Calculating a compensation amount from a difference between the measurement information and the control output causing the delay;
And compensating the measurement information with the calculated compensation amount.

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