JP2008090825A - Multiaxial control system with multi-dropped position detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To distribute a load on a central CPU of a multiaxial control system to servo control circuits, and give position information from multi-dropped position detectors to the servo control circuits independently of the CPU. <P>SOLUTION: A controller has a master communication circuit and the position detectors have slave communication circuits, so that signal lines of the position detectors can be multi-dropped, and dedicated signal lines are laid between the master communication circuit and the servo control circuits. The servo control circuits may be integrated for a plurality of axes. The master communication circuit may further be integrated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a multi-axis control system in which a plurality of position detectors attached to a plurality of motors are connected in a multidrop connection to control the plurality of motors.

In the multi-axis control system, a system is configured by controlling a plurality of motors. Since the motor power line and the signal line of the position detector are wired to the motor, the cable laying becomes complicated. Therefore, the number of signal lines was reduced by connecting the position detector and the control device using a network or serial communication line.
For example, in Patent Document 1, an encoder is connected to a control device using a network.
In Patent Document 2, the position detector and the motor driver of the control device are daisy chain connected by a serial communication line, and the motor driver is connected to the control board of the control device. Each motor driver requests position information from the corresponding position detector, receives it, processes it, gives it to the control board, and the control board takes the position data into account and gives an operation command to the servo driver. Giving a signal.

FIG. 9 shows the configuration of a general multi-axis control system in the case where the position detector is multi-drop connected using such a network or serial communication line. The controller 100 includes a CPU 1 that controls a multi-axis control system including servo control, a memory 2 that the CPU 1 uses, servo control circuits 31 to 3n for the number of axes of the motors 61 to 6n, and power to the motors 61 to 6n. Amplifier circuits 51 to 5n for supply are provided (power lines for supplying power to the amplifier circuits 51 to 5n are not shown).
On the other hand, the multi-axis machine main body 200 is provided with motors 61 to 6n corresponding to the number of axes and position detectors 81 to 8n that detect position information of the motors 61 to 6n, and the position detectors 81 to 8n. The slave communication circuits 71 to 7n are attached to the master communication circuit 4 provided in the controller 100, and the position information generated by the multi-axis position detectors 81 to 8n connected to the multidrop is transmitted to the communication line. 300 is transmitted.

The position information generated by the position detectors 81 to 8n received by the master communication circuit 4 is received by the CPU 1 via the local bus 10 and transferred to the position control process 601 in the block diagram shown in FIG.
FIG. 10 shows a block diagram of servo control executed by the CPU 1, but a command generation process 600 that generates an instruction to each axis by interpreting an application program (not shown), a position control process 601 that performs position control, A speed control process 602 for giving a torque command to the current control process 603 is executed. In the speed control process 602, the position information generated by the position detector is differentiated 604 and used as speed feedback information.
On the other hand, in the servo control circuits 31 to 3n, the PWM signal generated by the current control processing 603 is given to the amplifier circuit 50, and the power supplied to the motor 60 is controlled by the amplifier circuit 50.
Japanese Patent Laid-Open No. 7-49708 (FIG. 7) JP-A-10-275006 (FIG. 1, items 0014 to 0017)

  In the conventional multi-axis control system using the general multi-drop connection as shown in FIG. 9, the slave communication circuit in which the position information of the plurality of position detectors 81 to 8n is attached to each position detector 81 to 8n. The data is transmitted from 71 to 7n to the master communication circuit 4 attached to the controller. The CPU 1 reads the position information generated by the position detectors 81 to 8n of each axis received by the master communication circuit 4 through the local bus 10, generates a command to the motor, and performs position control, speed control, etc. Arithmetic processing is performed, and torque commands are issued to the servo control circuits 31 to 3n of the respective axes via the local bus 10.

In the case of such a conventional multi-axis control system, a single CPU generates a command for a multi-axis motor and performs arithmetic processing such as position control and speed control. A high-speed CPU and peripheral memory are required to adapt to (such as processing to prevent interference between motor shafts), and the local bus 10 to the master communication circuit 4 and the servo control circuits 31 to 3n is required. Therefore, it is necessary to increase the access speed, which causes problems such as device heat generation and cost increase. In addition, if a cooling mechanism such as a heat sink is installed to prevent heat generation, there arises a problem that the size of the controller is increased.
Therefore, in order to reduce the load on the CPU, it is conceivable to distribute the position control after each axis to the servo control circuit, but even in this case, the CPU reads the position information from the master communication circuit and outputs it to the servo control circuit. CPU load for the transfer processing is unavoidable. In addition, it is inevitable that the transfer processing time is wasted time for servo control.

  The present invention has been made in view of such problems, and in a multi-axis controller in which the position detector is multidrop connected by a serial communication line, the position control and the like are servo-controlled to reduce the load on the CPU. It is an object to supply position information to a servo control circuit without passing through a CPU even when the circuit is shared.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a motor, a position detector that detects the position of the motor attached to the motor, an amplifier circuit that supplies current to the motor, and a servo control circuit that controls the amplifier circuit A plurality of slave communication circuits that are attached to the plurality of position detectors and serially communicate position information of the plurality of motors, a plurality of the slave communication circuits, and a multi-axis control system including a plurality of sets. Drop-connected to receive the position information of the plurality of motors, and connected to the plurality of servo control circuits by a plurality of dedicated signal lines to transmit the position information of the plurality of motors to the plurality of servo control circuits A master communication circuit;
Is further provided.

  The invention of claim 2 is characterized in that, in claim 1, a plurality of the servo control circuits are integrated into a multi-axis servo control circuit and connected to the master communication circuit by a plurality of dedicated signal lines. is there.

  A third aspect of the present invention is characterized in that, in the first aspect, the plurality of servo control circuits and the master communication circuit are integrated into a multi-axis servo control circuit with a built-in master communication circuit.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the master communication circuit transmits the position information to the servo control circuit each time the position information is received. .

  According to a fifth aspect of the present invention, in any one of the first to third aspects, the master communication circuit transmits the position information to the servo control circuit at the same time.

  According to a sixth aspect of the present invention, in the first or second aspect, the dedicated signal line performs serial communication.

  According to a seventh aspect of the present invention, in any one of the first to third aspects, the master communication circuit is configured by serial processing.

  According to an eighth aspect of the present invention, in any one of the first to third aspects, the servo control circuit includes a function of executing position control, speed control, current control, and differential processing of the position information of the motor. It is characterized by.

  According to a ninth aspect of the present invention, in any one of the first to third aspects, the servo control circuit issues an interrupt signal to the CPU when the reception of the position information from the master communication circuit is completed. It is characterized by.

  According to a tenth aspect of the present invention, in any one of the first to third aspects, the servo control circuit starts servo processing simultaneously when the reception of the position information from the master communication circuit is completed. It is a feature.

  According to the first aspect of the present invention, since the position information generated by the position detector is transmitted from the master communication circuit to the servo control circuit of the plurality of motors via the dedicated signal line, the CPU transmits the position of the plurality of motors from the master communication circuit. There is no need to read the position information generated by the detector, and the processing load on the CPU can be reduced. The time for data transfer processing by the CPU becomes unnecessary, and the dead time inside the servo control circuit can be reduced.

  According to the invention described in claim 2, since the servo control of a plurality of motors is processed by one servo control circuit, when the servo control circuit is configured by an ASIC or the like, the external dimensions of the system can be greatly reduced. And cost can be reduced.

  According to the third aspect of the present invention, the servo control circuit for a plurality of motors and the master communication circuit for receiving the motor position information from the multi-drop connected position detector are combined into one servo control circuit. When the control circuit is configured by an ASIC or the like, the external dimensions of the system can be further reduced, and the cost can be further reduced.

  According to the invention described in claims 4 to 6, since the master communication circuit is connected to each servo control circuit through a dedicated serial communication line, the number of wirings can be reduced and the size can be reduced.

  According to the seventh to tenth aspects of the present invention, the master communication circuit, the servo control circuit, and the CPU can operate in synchronization with each other. Furthermore, the CPU generates multiple axis motor commands, and operations such as position control, speed control, current control, and position information differentiation are processed inside the servo control circuit. Can be reduced. Therefore, even in applications that require high-performance processing such as processing to prevent interference between motor shafts, it is not necessary to use a high-speed CPU, so less power is consumed and cooling of a heat sink for heat generation countermeasures is reduced. There is no need to install a mechanism, and the system can be downsized.

  As described above, according to the present invention, the access processing to the master communication circuit of the CPU of the controller is reduced, and the processing load of the CPU is distributed to the servo control circuit, thereby reducing the processing load on the CPU. In addition, a multi-axis control system with high performance, small size, and low power consumption can be realized.

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

FIG. 1 shows a first embodiment of the present invention, and is a configuration diagram of a multi-axis control system in which a plurality of position detectors attached to a plurality of axes are connected in a multi-drop manner.
Reference numeral 100 denotes a controller, which includes the following elements. 1 is a CPU that supervises the system including servo control, 2 is a memory used by the CPU, 31 to 3n are servo control circuits corresponding to the number of motor axes, and 4 is a position of a plurality of motors from a plurality of multi-drop connected position detectors. A master communication circuit for receiving information via a serial communication line 300 and transmitting the information to a plurality of servo control circuits 31 to 3n via a dedicated signal line 20, 5 operates the servo control circuits 31 to 3n and the master communication circuit 4. Clock circuits 51 to 5n for generating clocks necessary for the control are amplifier circuits for controlling the power supplied to the motors 61 to 6n by the PWM signal output from the servo control circuit.
The dedicated signal line 20 is for connecting the master communication circuit 4 and each of the servo control circuits 31 to 3n 1: N and transmitting position information of the motors 61 to 6n by serial communication.

  Reference numeral 200 denotes a multi-axis machine main body, reference numerals 61 to 6n denote motors, and reference numerals 81 to 8n denote position detectors that are attached to the motor and measure positions thereof. The motors 61 to 6n are connected to the amplifier circuits 51 to 5n through the motor power line 400, and slave communication circuits 71 to 7n are mounted inside the position detectors 81 to 8n, and the master communication installed in the controller 100. The circuit 4 is connected to the circuit 4 by a multi-drop-connected serial communication line 300.

  A clock signal 700 is input from the clock circuit 5 to the servo control circuits 31 to 3n, and a clock signal 701 necessary for the CPU 1 to operate by dividing or multiplying the clock inside the servo control circuits 31 to 3n. Output. In addition, when the servo control circuits 31 to 3n complete the reception of the position information from the master communication circuit 4, an INT signal 702 is output to notify the CPU 1 of an interrupt. A clock signal 701 and an INT signal 702 necessary for the operation of the CPU 1 output from the servo control circuit 31 among the plurality of servo control circuits 31 to 3n are connected to the CPU 1. As a result, the servo control circuits 31 to 3n and the CPU 1 operate on the basis of one clock circuit 5, so that the servo control is executed by the plurality of servo control circuits 31 to 3n and the CPU 1 in synchronization. As shown in FIG. 7, every time the master communication circuit 4 receives the position information of the motors 61 to 6 n from the plurality of position detectors 81 to 8 n via the serial communication line 300, the dedicated signal line 20 is used. Are transmitted to the servo control circuits 31 to 3n.

Next, the operation will be described with reference to FIGS.
The CPU 1 inside the controller 100 generates command values to be given to the servo control circuits 31 to 3n of the motors 61 to 6n in order to control the plurality of motors 61 to 6n simultaneously.
The servo control circuits 31 to 3n receive the command values, generate PWM signals, and output the PWM signals to the amplifier circuits 51 to 5n. Each amplifier circuit 51-5n controls the electric power supplied to each motor 61-6n based on the PWM signal.
The motors 61 to 6n are driven by the electric power, but the position detectors 81 to 8n attached to the motors 61 to 6n measure the positions of the motors 61 to 6n. Each of the position detectors 81 to 8n includes slave communication circuits 71 to 7n, and when the position information transmission request 310 of each of the motors 61 to 6n generated by the position detectors 81 to 8n is received from the master communication circuit 4, The measured position information of each of the motors 61 to 6n is transmitted to the master communication circuit 4 via the communication line 300.
When the master communication circuit 4 inside the controller 100 receives the position information of the motors 61 to 6n from the slave communication circuits 71 to 7n of the position detectors 81 to 8n via the communication line 300, the master communication circuit 4 via the dedicated signal line 20 It transmits to each servo control circuit 31-3n.
Such a series of processes is repeated at a predetermined control cycle as shown in FIG.
The servo control circuits 31 to 3n start a series of processes at the timing when the reception of the position information of the motors 61 to 6n is completed, and can operate in synchronization with each other.

Next, every time the master communication circuit 4 receives the position information of the motors 61 to 6n from the slave communication circuits 71 to 7n of the position detectors 81 to 8n, the master communication circuit 4 transmits the position information to the servo control circuits 31 to 3n. explain.
The master communication circuit 4 in that case will be described with reference to FIG.
The dedicated signal line 20 is connected to the input selector 44 of the master communication circuit 4, and the input selector 44 selects one of the dedicated signal lines 20 and outputs a signal transmitted thereon to the output serial processing unit 42. To do.
The input serial processing unit 43 generates an output selection signal 46 every time the position information transmitted from the slave communication circuits 71 to 7n of the position detectors 81 to 8n is received through the communication line 300. The output selector 45 selects one of the dedicated signal lines 20 based on the output selection signal 46 and transmits position information to the dedicated signal line 20.

A different configuration of the master communication circuit 4 will be described with reference to FIG.
The dedicated signal line 20 is connected to the output serial processing units 421 to 42n of the master communication circuit 4, and the output serial processing units 421 to 42n are connected to the input selector 44. The output serial processing units 421 to 42n generate input selection signals 471 to 47n when communication is performed using the dedicated signal line 20, and the input selector outputs serial signals based on the input selection signals 471 to 47n. The processing units 421 to 42n are selected, and signals from the processing units 421 to 42n are transmitted to the communication line 300. The input serial processing unit 43 is the same as in the case of FIG.

Next, a series of operations will be described with reference to FIGS.
The servo control circuits 31 to 3n transmit a transmission request to the dedicated signal line 20 so as to transmit the position information of the motors 61 to 6n to the slave communication circuits 71 to 7n of the position detectors 81 to 8n. The master communication circuit 4 transmits the transmission request transmitted to the dedicated signal line 20 (1) to the communication line 300 as the transmission request 310. At this time, a delay 1 occurs because the output serial processing unit 42 is passed through.
The slave communication circuits 71 to 7n of the position detectors 81 to 8n that have received the transmission request 310 transmit the position information 301 to 30n to the communication line 310.
Each of the slave communication circuits 71 to 7n has a timer, and calculates and transmits the transmission timing from a predetermined set value of the timer and the address (# 1 to #n) of each of the slave communication circuits 71 to 7n. Thus, communication data is prevented from colliding on the communication line 300.
The master communication circuit 4 determines which servo control circuit 31 to 3n is to be transmitted from each position information, and transmits the position information to the determined dedicated signal line 20. At this time, a delay 2 occurs because it passes through the input serial processing unit 43. Finally, the position information is transmitted to the dedicated signal line 20 (1), and after receiving the position information, the servo control circuit 31 generates an INT signal 702 that is an interrupt to the CPU1. The CPU 1 that has received the interrupt by the INT signal 702 outputs a position command to each servo control circuit 31 to 3n, and each servo control circuit 31 to 3n starts servo processing.

  As shown in FIG. 8 instead of FIG. 7, after the master communication circuit 4 has received all the position information of the motors 61 to 6 n from the plurality of position detectors 81 to 8 n via the serial communication line 300, It is also possible to transmit to each of the servo control circuits 31 to 3n via the dedicated signal line 20. In this case, the position information received by the input serial processing unit 43 shown in FIGS. 2 and 3 is buffered by the number of all axes and simultaneously sent to the dedicated signal lines 20 corresponding to the servo control circuits 31 to 3n.

  FIG. 4 shows a second embodiment of the present invention. The servo control circuits 31 to 3n provided separately for each axis in the first embodiment shown in FIG. 1 are collectively mounted on one multi-axis servo control circuit 40, the master communication circuit 4 and the multi-axis servo. The difference from the first embodiment is that the dedicated signal lines 20 connected to the control circuit 40 are provided by the number of controllable motors. Since the operation is the same as that of the first embodiment, the description thereof is omitted.

  FIG. 5 shows a third embodiment of the present invention. In addition to the servo control circuits 31 to 3n provided separately for each axis in the first embodiment shown in FIG. 1, the master communication circuit 4 is also integrated into one master communication circuit built-in multi-axis servo control circuit 41. This is different from the first and second embodiments. Since the operation is the same as in the first and second embodiments, description thereof is omitted.

  FIG. 6 shows a fourth embodiment of the present invention and is a block diagram showing a control method. Reference numeral 600 denotes a command generation process executed by the CPU 1, which generates an instruction value to be given to the servo control circuits 31 to 3n of each axis by interpreting an application program (not shown). P601 of each servo control circuit 31 to 3n is position control processing, V602 is speed control processing, I603 is current control processing, and differentiation 604 is differentiation processing.

Next, the operation will be described using the hardware of FIG. 1 and FIG.
In the hardware of the first embodiment, the CPU 1 in the controller 100 performs command generation processing for the number of motor axes, and outputs command values for the motors to the servo control circuits 31 to 3n. This command value is input to the servo control circuits 31 to 3n of the respective axes, and position control processing is performed together with position information fed back from the position detectors 81 to 8n. Thereafter, the speed control process is performed based on the speed command value generated from the position control process and the speed feedback information generated by differentiating the position information fed back from the position detectors 81 to 8n. Subsequently, the current control process is performed based on the current command value generated from the speed control process and the detected current value monitored at the output unit of each amplifier circuit 51 to 5n. This result is converted into a PWM waveform to the motor and output to the amplifier circuits 51 to 5n to control the power supplied to the motors 61 to 6n of the respective axes.

Thereafter, as in the first embodiment, the position information transmission request 310 generated by the position detectors 81 to 8n is output from the master communication circuit 4 to the position detectors 81 to 8n installed in the motors 61 to 6n. Based on this transmission request, in each of the position detectors 81 to 8n, the slave communication circuits 71 to 7n output the position information of the local station motor to the communication line 300 as shown in FIG. When the master communication circuit 4 in the controller 100 receives the position information generated by the position detectors 81 to 8n for all axes, the position information generated by the position detectors 81 to 8n is sent to the servo control circuits 31 to 3n for the respective axes. It communicates via the connected dedicated signal line 20 and is used for servo control of the next cycle.
Note that this control method can also be realized in the hardware of the second and third embodiments.

  According to the present invention, in an FA device composed of a plurality of motors, it is possible to reduce the number of signal lines connecting the position detector without degrading the CPU processing performance.

Configuration diagram of a multi-axis control system using a multi-drop connected position detector showing a first embodiment of the present invention 1 is a block diagram of a master communication circuit showing a first embodiment of the present invention. 1 is a block diagram of a master communication circuit showing a first embodiment of the present invention. Multi-axis control system configuration diagram by multi-drop connected position detector showing a second embodiment of the present invention Multi-axis control system configuration diagram by multidrop connection position detector showing a third embodiment of the present invention Block diagram showing the control method of the present invention The figure which shows the transmission path of the multidrop communication of this invention, and a dedicated signal line The figure which shows the transmission path of the multidrop communication of this invention, and a dedicated signal line Multi-axis control system configuration diagram of a conventional example Block diagram showing a control method in a conventional multi-axis control system configuration

Explanation of symbols

1 CPU
DESCRIPTION OF SYMBOLS 10 Local bus 2 Memory 20 Dedicated signal line 30 Servo control circuit 31-3n Servo control circuit 4 Master communication circuit 40 Multi-axis servo control circuit 41 Master communication built-in multi-axis servo control circuit 42 Output serial processing part 421-42n Output serial processing part 43 Input Serial Processing Unit 44 Input Selector 45 Output Selector 46 Output Selection Signals 471-47n Input Selection Signal 5 Clock Circuit 50 Motor Power Amplifier Circuit
51-5n Motor power amplifier circuit
60 motor 61-6n motor
71-7n Slave communication circuit
80 Position detectors 81 to 8n Position detector 100 Controller 101 PC controller 102 Servo controller 200 Multi-axis machine main body 300 Communication lines 301 to 30n Position detector data 310 Transmission request 400 Motor power line 500 Position detector signal line 600 Command generation processing 601 Position control processing 602 Speed control processing 603 Current control processing 604 Differentiation processing 700 Clock signal 701 CPU operation clock signal 702 INT signal

Claims (10)

A multi-axis comprising a plurality of sets of a motor, a position detector that detects the position of the motor attached to the motor, an amplifier circuit that supplies power to the motor, and a servo control circuit that controls the amplifier circuit In the control system,
A plurality of slave communication circuits attached to the plurality of position detectors for serial communication of position information of the plurality of motors;
The plurality of slave communication circuits are multidrop connected to receive the position information of the plurality of motors, and the plurality of servo control circuits are connected to the plurality of dedicated signal lines to be connected to the plurality of motor position information. A master communication circuit for transmitting to the servo control circuit;
A multi-axis control system characterized by further comprising: 2. The multi-axis control system according to claim 1, wherein the plurality of servo control circuits are integrated into a multi-axis servo control circuit and connected to the master communication circuit by a plurality of dedicated signal lines. 2. The multi-axis control system according to claim 1, wherein a plurality of the servo control circuits and the master communication circuit are integrated into a master communication circuit built-in multi-axis servo control circuit. 4. The multi-axis control system according to claim 1, wherein the master communication circuit transmits the position information to the servo control circuit every time the position information is received. 5. 4. The multi-axis control system according to claim 1, wherein the master communication circuit simultaneously transmits the position information to the servo control circuit. 3. The multi-axis control system according to claim 1, wherein the dedicated signal line performs serial communication. 4. The multi-axis control system according to claim 1, wherein the master communication circuit is configured by serial communication processing. 4. The multi-axis control system according to claim 1, wherein the servo control circuit includes a function of performing position control, speed control, current control, and differentiation processing of the position information of the motor. 5. 4. The multi-axis control system according to claim 1, wherein the servo control circuit issues an interrupt signal to the CPU when the reception of the position information from the master communication circuit is completed. 4. The multi-axis control system according to claim 1, wherein the servo control circuit starts servo processing at the same time when the reception of the position information from the master communication circuit is completed.

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