JP2016036230A - Serial servo bus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a serial servo bus which enables the reduction in cost which eliminates the need for having the limitation in synchronizing control of a motor by branching communications in a power-supply module and using a numerical controller to all motor controls.SOLUTION: A serial servo bus enables the materialization of serial buses (branch line) 9, 9' by use of communication paths of lower speed and lower cost. The function of branching from a serial bus (trunk) 2 to the serial buses (branch lines) 9, 9' is incorporated in each of power-supply modules 3, 3'. Data exchanged through the serial buses (branch lines) 9, 9' are limited to command values to servo modules 4-1, 4-2, 4'-1, 4'-2 connected with the branch lines and feedbacks from the servo modules 4-1, 4-2, 4'-1, 4'-2. The quantity of communications exchanged through the serial buses (branch lines) 9, 9' is reduced in comparison to that on the serial bus (trunk) 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a serial servo bus that connects between a numerical control device that controls a machine tool, industrial machine, or robot and a servo amplifier that drives a servo motor.

  Conventionally, as a connection method between a numerical controller (CNC) and a plurality of servo amplifiers in a machine tool, a method of connecting a CNC and a servo amplifier with a daisy chain serial bus (Patent Document 1), or a control of a plurality of servo amplifiers There has been proposed a method (Patent Document 2) in which a motor control unit for performing the above is prepared separately from the CNC, and the motor control unit and the CNC are connected by a daisy chain serial bus.

  In the method of Patent Document 1, a bandwidth for the CNC to communicate with all the servo amplifiers is required for the serial bus. Since all the servo amplifiers are connected to the serial bus, the servo amplifiers require a high-speed communication interface having a bandwidth sufficient for all servo amplifiers to communicate.

  On the other hand, in the method of Patent Document 2, the serial bus between the CNC and the motor control unit is required to have a bandwidth for communicating data for controlling all servo amplifiers, as in Patent Document 1. For communication between each motor control unit and the servo amplifier, only a band necessary for communication with the amplifier controlled by each motor control unit is required. Therefore, the communication interface of the servo amplifier can be made slower than the method of Patent Document 1, which has the advantage of reducing the cost.

  However, the method of Patent Document 2 has a problem that it is difficult to perform synchronous control across a plurality of motor control units. In the method disclosed in Patent Document 2, the CNC transmits position command information for each motor to the motor control unit, and the motor control unit provides current control information, which is finer control, to the servo amplifier based on the position command. Send. The servo amplifier controls the motor based on the current control information.

  Thus, since the current control information is exchanged only between the motor control unit and the servo amplifier, the motor control unit can refer to the current control information of the servo amplifier connected to the other motor control unit. I can't. When performing synchronous control of the motor, information on the current control of the motor that performs synchronous control is required, so that synchronous control across the motor control unit becomes difficult.

JP-A-9-69004 Japanese Patent No. 3892778

  As an example of a conventional servo motor control system, there is a system shown in FIG. 8 in which a CNC and a servo module are directly connected in a daisy chain by a serial bus. In the system shown in FIG. 8, a numerical controller 50 that controls a machine tool, an industrial machine, or a robot includes a servo module 52 that drives a servo motor 54, a servo module 53 that drives a servo motor 55, and a serial bus 58. Send and receive various data. In addition to the serial bus 58, the power supply module 51 and the plurality of servo modules 52 and 53 that receive DC power supply from the power supply module 51 are connected to a harness (DC power supply 56) for supplying DC power and an inter-module communication 57. Connected by a daisy-chain communication line.

  In the above system, since command values to the servo modules 52 and 53 connected to the serial bus 58 and feedback from the servo modules 52 and 53 are all exchanged on one serial bus 58, the serial bus between the servo modules The communication speed of 58 needs to be increased. Further, since the power supply module 51 is not connected by the serial bus 58, it is impossible to integrate the inter-module communication 57 and the serial bus 58.

  Therefore, in view of the above-mentioned problems of the prior art, the object of the present invention is to perform communication branching in the power supply module, and to perform all motor control with a numerical controller, without limiting the synchronous control of the motor, The present invention also provides a serial servo bus capable of reducing costs.

In the invention according to claim 1 of the present application, a servo amplifier generates one or a plurality of servo modules that generate a drive current to be sent to a servo motor, and a DC supplied from a commercial AC power source to the one or a plurality of servo modules. In a servo motor control system comprising a power supply module for generating a power supply, and one or more servo amplifiers connected to a numerical control device, each of the numerical control devices and the one or more servo amplifiers The power module is connected to the first serial bus in the form of a daisy chain, and each of the power modules and the one or more servo modules to which the power modules supply DC power are It is connected by a second serial bus in the form of a daisy chain that is separate from the bus. The command value for the module is transmitted via the first serial bus to the power supply module to which the commanded servo module is connected, and the power supply module commands the command value via the second serial bus. Sending to the previous servo module, feedback from each servo module to the numerical control device is sent from the servo module to the power supply module via the second serial bus, and the power supply module sends the feedback to the first servo module. The servo motor control system transmits to the numerical controller via one serial bus.
The first serial bus corresponds to the serial bus (main line) in the embodiment for carrying out the invention. The second serial bus corresponds to a serial bus (branch line) in the embodiment for implementation.
According to the first aspect of the present invention, the first serial bus to which the numerical control device with a lot of traffic is connected is a high-speed communication, but the communication between the servo modules with less traffic is more than the first serial bus. By using low-speed communication, the cost of the serial bus between servo modules can be reduced. Further, there is a possibility that the number of serial buses connected to the numerical control device can be reduced as compared with the case where the communication between the numerical control device and the servo module is a low-speed communication.

  The invention according to claim 2 is characterized in that the second serial bus is provided integrally with a harness that supplies DC power supplied from the power supply module to the one or more servo modules. The servo motor control system according to claim 1. Wiring is saved by providing it integrally with a harness for supplying DC power.

  The invention according to claim 3 is the servo motor according to claim 1, wherein the second serial bus is further used for communication between the power supply module and the one or more servo modules. Control system. The second serial bus is also used for communication between the power supply module and the one or more servo modules, thereby reducing wiring.

  According to the present invention, it is possible to provide a serial servo bus capable of reducing the cost without limiting the synchronous control of the motor by branching communication in the power supply module and performing all motor control by the numerical control device. .

It is a figure which shows Embodiment 1 of this invention. It is a figure which shows the example of the data transmitted to a serial bus (core) from a numerical controller. It is a figure which shows the power supply module internal circuit used in Embodiment 1, 2 of this invention (in the case of the data flow from upstream to downstream). It is a figure which shows the other power supply module internal circuit used in Embodiment 1, 2 of this invention (in the case of the data flow from downstream to upstream). It is a figure which shows Embodiment 2 of this invention. It is a figure which shows Embodiment 3 of this invention. It is a figure which shows the other power supply module internal circuit used in Embodiment 3 of this invention. It is a figure which shows the conventional serial servo bus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The servo motor control system according to the present invention can be used as a control system for machine tools, industrial machines, or robots. In the following description of the embodiment, an example of a machine tool control system will be described.

<Embodiment 1>
FIG. 1 is a diagram showing Embodiment 1 of the present invention. The servo motor control system according to the first embodiment of the present invention includes a numerical controller 1 that controls a machine tool (not shown), a servo motor that receives a command value from the numerical controller 1, and a servo motor that Are fed from a plurality of servo amplifiers that return the feedback to the numerical controller 1.

  Here, in FIG. 1, the servo amplifier includes a power module 3 that is a converter that generates DC power from a commercial AC power (AC 200 V), and a servo module 4 that drives the servo motors 5 and 6 by receiving the DC power. It is configured as a group including -1,4-2.

  The numerical controller 1 and the plurality of power supply modules 3, 3 ′ are connected in a daisy chain by a serial bus 2. The power supply module 3 and a plurality of servo modules 4-1 and 4-2 that are supplied with DC power from the power supply module 3 are connected in a daisy chain by a serial bus (branch line) 9. In addition to the serial bus (branch line) 9, the power supply module 3 and the plurality of servo modules 4-1 and 4-2 that are supplied with DC power from the power supply module 3 have a harness (DC power supply) that supplies DC power. Line 7) and a daisy chain communication line (inter-module communication line 8) for inter-module communication.

  The power supply module 3 ′ and a plurality of servo modules 4′-1 and 4′-2 receiving DC power from the power supply module 3 ′ are connected in a daisy chain by a serial bus (branch line) (not shown). . Further, the power supply module 3 ′ and the plurality of servo modules 4′-1 and 4′-2 that receive supply of DC power from the power supply module 3 ′ supply DC power in addition to the serial bus (branch line) 9 ′. They are connected by a harness (not shown) and a daisy chain communication line (not shown) for inter-module communication.

  In the numerical controller 1, command values for individual servo modules 4-1, 4-2, 4'-1, 4'-2 are connected to the command destination servo module via the serial bus (core) 2. The power supply module transmits the command value to the commanded servo module via the serial bus (branch lines) 9 and 9 ′. Conversely, feedback information from the individual servo modules 4-1, 4-2, 4'-1, 4'-2 to the numerical control device 1 is the servo modules 4-1, 4-2, 4'-1, 4 The power is sent from “−2” to the power supply modules 3 and 3 ′ via the serial bus (branch lines) 9 and 9 ′, and the power supply modules 3 and 3 ′ are sent to the numerical controller 1 via the serial bus (core) 2.

  As described above, by branching the serial bus (branch line) 9, 9 ′ from the serial bus (core) 2, the data exchanged on the serial bus (branch line) 9, 9 ′ is a servo connected to the branch line. It is limited to command values for modules and feedback from those servo modules. For this reason, since the amount of communication exchanged with the serial bus (branch line) 9, 9 'is smaller than that of the serial bus (main trunk) 2, the serial bus (branch line) 9 is used by using a lower-speed and lower-cost communication path. , 9 'can be realized, leading to cost reduction for the entire system. Further, by incorporating a function for branching the serial bus (branch lines) 9 and 9 'from the serial bus (core) 2 into the power supply modules 3 and 3', compared to a case where a device for realizing the branch function is separately prepared. Therefore, it is possible to realize a system at low cost and space saving.

  FIG. 2 is a diagram illustrating an example of data transmitted from the numerical controller to the serial bus (core). Reference numeral D1 represents data on the trunk side serial bus, reference numeral DG1 represents data on the branch side serial bus for the group G1, and reference numeral DG2 represents data on the branch side serial bus for the group G2. A time image of data transfer in the serial bus (main trunk) 2 and the serial bus (branch lines) 9 and 9 'is shown. Data transmitted from the numerical controller 1 to the servo amplifier of the group G1 composed of the power supply module 3 and the servo modules 4-1 and 4-2 is transmitted via the high-speed serial bus (core) 2. Is done. Reference numeral D0 indicates data on the trunk side serial bus, reference numeral DG1 indicates data on the branch line side serial bus for the group G1, and reference numeral DG2 indicates data on the branch line side serial bus. Data D0 includes data DG1 and data DG2.

  D3 is data for the power supply module 3, D4-1 is data for the servo module 4-1, and D4-2 is data for the servo module 4-2.

  Similarly, the data transmitted from the numerical controller 1 to the servo amplifier of the group G2 composed of the power supply module 3 ′ and the servo modules 4′-1 and 4′-2 is also a high-speed serial bus (core ) 2 is transmitted. D3 'is data for the power supply module 3, D4'-1 is data for the servo module 4'-1, and D4'-2 is data for the servo module 4'-2.

  Here, the serial buses (branch lines) 9 and 9 ′ have a smaller number of communication targets than the serial bus (core) 2, and therefore communication with a lower bit rate can be selected.

  Next, the power supply module will be described. 3 and 4 are diagrams showing an internal circuit of the power supply module used in Embodiment 1 of the present invention. The power supply modules 3 and 3 ′ in FIG. 1 will be described as a power supply module 30. The power supply module 30 includes an upstream trunk communication circuit 31, a downstream trunk communication circuit 32, a branch line side communication control circuit 33, and an inter-module communication circuit 34.

  First, transmission data (data A) to each servo amplifier is transmitted via the serial bus (core) 2 from another power supply module or numerical controller 35 existing upstream on the serial bus (core) 2 side. The transmitted data A is once taken into the upstream trunk communication circuit 31 in the power supply module 30 via the trunk serial bus (upstream) 36, and then directly via the downstream trunk communication circuit 32. It is transmitted to the serial bus (downstream) 37.

  On the other hand, the upstream trunk communication circuit 31 among the captured data A from the numerical controller 1 is data for the servo module connected to the serial bus (branch line) 38 connected to the power supply module 30 (data). If there is B), the upstream backbone communication circuit 31 transfers it to the corresponding servo module via the branch line side communication control circuit 33.

  Data (data C) transmitted from the other power supply module 40 connected to the main serial bus (downstream) 37 of the power supply module 30 to the numerical controller 1 passes through the main serial bus (downstream) 37. Then, it is input to the downstream trunk communication circuit 32 of the power supply module 30.

  On the other hand, the servo module connected to the serial bus (branch line) 38 on the branch line sends data (data D) to be transmitted to the numerical controller 1 to the branch side communication control circuit 33 in the power supply module 30. The branch line side communication control circuit 33 further sends it to the upstream trunk communication circuit 31. The upstream trunk communication circuit 31 transmits the sent data D and data C to the numerical controller 1 via the trunk serial bus (upstream) 36.

<Embodiment 2>
FIG. 5 is a diagram showing Embodiment 2 of the present invention. In the servo motor control system according to the first embodiment of the present invention, a serial bus (branch line) connecting the power supply module 10 and the servo modules 11 and 12 supplies DC power supplied from the power supply module 10 to the servo modules 11 and 12. The harnesses 13 and 14 are integrally formed (see reference numeral 17), and other configurations are the same as those of the servo motor control system described in the first embodiment. By integrating the DC power supply harnesses 13 and 14 and the serial bus (branch line), wiring saving between the power supply module 10 and the servo module 11 and wiring saving between the servo module 11 and the servo module 12 are realized. The internal configuration of the power supply module 10 is the same as that described with reference to FIGS.

<Embodiment 3>
FIG. 6 is a diagram showing Embodiment 3 of the present invention. In the servo motor control system according to the third embodiment of the present invention, a power supply module 20, a servo module 21 that drives the servo motor 23, and a serial bus (branch line) 26 that connects the servo module 22 that drives the servo motor 24 are connected between the modules. Other configurations are also used for communication and are the same as those of the servo motor control system described in the first embodiment. A DC power supply 25 is supplied from the power supply module 20 to the servo module 21 and the servo module 22. By performing inter-module communication through the serial bus (branch line) 26, communication lines for inter-module communication are reduced, and wiring between the power supply module 20 and the servo module 21 and wiring between the servo modules 21 and 22 are reduced. Realize.

  FIG. 7 is a diagram showing another internal circuit of the power supply module used in Embodiment 3 of the present invention. In the servo motor control system of the third embodiment, the inter-module communication circuit 34 communicates the inter-module communication data 41 with the servo modules connected via a serial bus (branch line) 38. That is, the data transmitted by the inter-module communication circuit 34 to the power supply module 20 or the servo modules 21 and 22 is transmitted to the power supply module or the servo module via the branch line side communication control circuit 33 and the serial bus (branch line) 38. . The data transmitted from the power supply module 20 or the servo modules 21 and 22 to the inter-module communication circuit 34 reaches the inter-module communication circuit 34 via the serial bus (branch line) 38 and the branch line side communication control circuit 33. .

1 Numerical control device 2 Serial bus (core)
3, 3 'power supply module 4-1, 4-2, 4'-1, 4'-2 servo module 5 servo motor 6 servo motor 7, 7' DC power supply line 8 inter-module communication line 9 serial bus (branch line)
DESCRIPTION OF SYMBOLS 10 Power supply module 11, 12 Servo module 13 Harness 14 Harness 15 Servo motor 16 Servo motor 17 DC power supply 18 Serial bus (branch line)
19 Inter-module communication 20 Power module 21 Servo module 22 Servo module 23 Servo motor 24 Servo motor 25 DC power supply 26 Serial bus (branch line)

30 power supply module 31 upstream backbone communication circuit 32 downstream backbone communication circuit 33 branch side communication control circuit 34 inter-module communication circuit 35 other power supply module or control circuit 36 backbone serial bus (upstream)
37 Main serial bus (downstream)
38 Serial bus (branch line)
39 Inter-module communication 40 Other power supply modules 41 Inter-module communication data

50 Numerical Control Device 51 Power Module 52 Servo Module 53 Servo Module 54 Servo Motor 55 Servo Motor 56 DC Power Supply 57 Intermodule Communication 58 Serial Bus

D0 Data on main serial bus DG1 Data on branch serial bus DG2 Data on branch serial bus D3 Data for power module 3 D3 'Data for power module 3' D4-1 Data for servo module 4-1 D4 ' -1 Data for servo module 4'-1 D4-2 Data for servo module 4-2 D4'-2 Data for servo module 4'-2 G1 Group 1
G2 Group 2

Claims (3)

The servo amplifier is composed of one or a plurality of servo modules that generate a drive current to be sent to the servo motor, and a power supply module that generates a DC power supplied from a commercial AC power source to the one or a plurality of servo modules. In a servo motor control system in which one or a plurality of servo amplifiers are connected to a numerical controller,
Each power supply module provided in the numerical controller and the one or more servo amplifiers is connected to a first serial bus in the form of a daisy chain,
Each power supply module and the one or more servo modules to which each power supply module supplies DC power are connected by a second daisy-chain serial bus different from the first serial bus. ,
The numerical controller transmits a command value for each servo module to the power supply module to which the commanded servo module is connected via the first serial bus, and the power supply module sends the command value to the power supply module. Send to the commanded servo module via the second serial bus,
Feedback from each servo module to the numerical control device is transmitted from the servo module to the power supply module via the second serial bus, and the power supply module sends the feedback via the first serial bus to the numerical control device. Servo motor control system, characterized in that   2. The servo according to claim 1, wherein the second serial bus is provided integrally with a harness that supplies DC power supplied from the power supply module to the one or a plurality of servo modules. Motor control system.   2. The servo motor control system according to claim 1, wherein the second serial bus is further used for communication between the power supply module and the one or a plurality of servo modules.

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