JP2006285886A - Control method of distributed motion control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the number of shafts of which synchronous interpolation control is executed even when using a communication line with the same performance as in the past. <P>SOLUTION: A motion controller 101 which carries shaft command creation parts 121 and shaft control parts 131 is connected to the communication line 100 for synchronous communications and when a multi-shaft interpolation command D is input, the shaft command creation parts 121 and the shaft control parts 131 of each motion controller 101 are synchronized with each other for controlling each shaft. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a control method for a distributed motion control system that performs synchronous interpolation control of a plurality of motors.

A conventional numerical control apparatus includes a numerical control unit and a plurality of axis control units connected to each other via a network (see, for example, Patent Document 1), and FIG. 5 is a block diagram showing the configuration. This numerical control device includes a numerical control unit 510, axis control units 520 and 530, and a screen control unit 540, which are connected via a network 550. The numerical controller 510 includes a numerical controller 511 that controls the entire numerical controller, a PMC controller 512 that controls the machine tool, and a network controller 513 that controls the network 550. The axis controllers 520 and 530 are composed of axis controllers 521 and 531 that control a servo drive system (not shown) and network controllers 522 and 532 that control the network 550. For simplification, only two axis controllers are shown, but in practice, the required number of axis controllers is used according to the transfer capability of the network. The screen control unit 540 includes a screen controller 541 that controls an input / output device (not shown) such as a CRT / MDI and a network control unit 542 that controls the network 550. With such a configuration, data can be transmitted and received between the numerical controller 510, the axis controllers 520 and 530, and the screen controller 540 via the network 550.
The numerical controller 511 creates axis commands for all the axis control units 520 and 530 that perform synchronous interpolation control, and transmits the axis commands to the network 550 at predetermined constant communication cycles. When the axis control units 520 and 530 receive the respective axis commands, it is estimated that the axis control units 520 and 530 perform synchronous interpolation control by synchronizing with a constant synchronization signal.
JP-A-9-73310 (5th page, FIG. 1).

In such a conventional numerical control device, the numerical control unit 510 generates a multi-axis axis command and has sufficient performance so as to be within the communication cycle of the network control units 522 and 532 in the axis control units 520 and 530. , The number of control axes for which synchronous interpolation can be performed is restricted by communication performance. That is,
(1) Normally, the communication cycle must be short enough to match the control cycle of the axis control unit,
(2) The number of axis control units connected to the network is determined in accordance with the amount of axis command data that can be transmitted within the required communication cycle, and is subject to restrictions on the data bandwidth of the network.
Therefore, even if the numerical control unit has a performance capable of converting a multi-axis interpolation command into an axis command, the number of axis control units that perform synchronous interpolation control cannot be increased due to restrictions on network communication performance. There was a problem of extensibility.

The present invention has been made in view of such problems, and there is provided a method capable of increasing the number of axes that can be controlled by synchronous interpolation compared to the conventional configuration even when using a communication line having the same communication performance as the conventional one. The purpose is to provide.

In order to solve the above problem, the present invention is as follows.
According to a first aspect of the present invention, there is provided a motion controller including a communication processing unit that is connected to a communication line and supports synchronous communication, an axis command generation unit that generates an axis command, and an axis control unit that receives the axis command and controls a motor. In a distributed motion control system provided in pairs with the motor, each motion controller operates according to the following procedure, and performs synchronous interpolation control of the motor based on an interpolation command. (1) The communication processing unit inputs an interpolation command in synchronization with the communication processing unit of another motion controller. (2) The axis command generation unit inputs the interpolation command in synchronization with an axis command generation unit of another motion controller, and generates an axis command for driving the motor. (3) The axis control unit inputs the axis command in synchronization with the axis control unit of another motion controller, and drives the motor. (4) The axis command generation unit operates in synchronization with the axis command generation unit of another motion controller, and the axis control unit operates in synchronization with the axis control unit of another motion controller.
The second invention is characterized in that when the motion controller detects an event, it operates according to the following procedure. (1) The communication processing unit inputs the event and transmits the event to another motion controller through the synchronous communication. (2) A communication processing unit of another motion controller receives the event through the synchronous communication. (3) Communication processing units of other motion controllers input the event in synchronization. (4) The axis command generation unit of each motion controller operates in synchronization with the input event.

According to the first aspect of the present invention, by providing a distributed motion control system that combines a drive-integrated motion controller and a network, the interpolation command input by the motion controller is an input to the axis command generator. Interpolation commands are used, and the amount of data is less than the number of axis commands for multiple axes. In addition, since the multi-axis interpolation command normally corresponds to several to several tens of axis commands, the communication cycle at the time of multi-axis interpolation command transmission can be set longer than that at the time of axis command transmission. Therefore, by adopting the configuration of the present invention, the number of axes that can be subjected to synchronous interpolation control can be increased even in a network having the same communication performance as in the conventional case as compared with the case of the conventional configuration.
Further, according to the second invention, since it is possible to take an action in synchronization with an event detected by any one of the motion controllers, for example, a deceleration stop event detected by a certain motion controller is set to all motions. Since the controller can process synchronously, an axis command that does not deviate from the interpolation trajectory of the multi-axis interpolation command can be generated.

Hereinafter, specific examples of the method of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a distributed motion control system for implementing the method of the present invention. In the figure, reference numerals 101 to 104 denote motion controllers, to which a communication line 100 that supports synchronous communication is connected. Further, each includes communication processing units 111 to 114, axis command generation units 121 to 124, and axis control units 131 to 134, and motors 151 to 154 with rotation detectors are connected. The communication processing units 111 to 114 receive the synchronization signal C of the communication line 100 and are synchronized with each other, and the axis command generation units 121 to 124 and the axis control units 131 to 134 are also synchronized with each other. The communication processing units 111 to 114 input the same interpolation command D according to the communication cycle of the communication line 100 and output it as it is, and the axis command generation units 121 to 124 receiving this generate the axis commands SP1 to SP4. is doing. The axis controllers 131 to 134 operate by inputting the axis commands SP1 to SP4 and the encoder feedbacks Ef1 to Ef4 of the motors 151 to 154, and drive the motors 151 to 154.

FIG. 2 is a timing chart showing the operation timing of the first control method of the distributed motion control system of FIG. Since the operations of the motion controllers 101 to 104 are all the same, a description will be given using the motion controller 101 as a representative. In the figure, the communication line 100 performs synchronous communication at a communication cycle T1. The axis command generation unit 121 is activated by a timer interruption every axis command generation cycle TF, and when an interpolation command D is input, generates an axis command SP1 and outputs it to the axis control unit 131. On the other hand, the axis control unit 131 is started by a timer interruption every axis control cycle T2, and when the axis command SP1 is input, the axis command SP1 is divided according to the axis command generation cycle TF and the axis control cycle T2. Here, since the axis command generation cycle TF is set to be twice the axis control cycle T2, the axis command SP1 is divided into two parts SP11 and SP12. Then, the axis controller 131 drives the motor 151 by performing two processes, SP11 process and SP12 process.

FIG. 3 is a flowchart showing a control algorithm of the first control method of the present invention. The operation of the motion controllers 101 to 104 shown in FIG. 1 will be described with reference to FIG. Since the operations of the motion controllers 101 to 104 are all the same, the motion controller 101 is used as a representative and will be described in order.
(S1) When the motion controller 101 is activated, the axis command generator 121 waits for timer interrupt activation (S2). Next, when the axis command generator 121 is activated by a timer interrupt,
(S3) The communication processing unit 111 confirms whether or not the interpolation command D has been received. If not received, the process returns to S1 and again waits for timer interrupt activation.
(S4) If the communication processing unit 111 receives the interpolation command D, the interpolation command D is input,
(S5) A speed corresponding to the interpolation command D is generated, and (S6) a next interpolation point vector corresponding to the speed is calculated,
(S7) Extract and output the components of the motor 151 from the next interpolation vector,
(S8) The motor 151 is driven.

Here, S3 to S7 will be specifically described as follows. First, as the interpolation command D, curve interpolation f (u) = (x (u), y (u), z (u)) (u is a curve parameter, u ≧ u0) is considered. When the axis command generation unit 121 inputs f (u) (S4), the interpolation speed V1 at the time when the axis command generation period TF has elapsed is calculated from the start point f (u0) of f (u) (S5). For example, when the tangential acceleration A is given, if the speed at the starting point is 0, the interpolation speed V1 is as follows.
V1 = A * TF
Using this V1, the movement distance ΔL1 at this time is as follows:
ΔL1 = V1 * TF / 2
The change amount Δu1 of the curve parameter at this time is as follows.
Δu1 = ΔL1 / | f '(u0) |
Therefore, the interpolation point at this time is calculated as follows (ST6).
f (u0 + Δu1) = (x (u0 + Δu1), y (u0 + Δu1), z (u0 + Δu1))

Next, the motion controller 101 converts the interpolation point f (Δu1) into the axis command SP1. Usually, in an articulated robot or a multi-axis machine tool, when converting the position of an arm or tool in a work space into an axis command to a motor, a conversion matrix called kinematics is used. Since the elements of this transformation matrix are functions of each position p in the work space, when the transformation matrix is M (p), the axis command SP1 is calculated as follows.
(SP1) = M (f (u0 + Δu1)) ・ f (u0 + Δu1)
(S7) Thereby, the axis command SP1 for the motor 151 is extracted,
(S8) The axis control unit 131 operates by inputting the axis command SP1 and the encoder feedback EF1 from the motor 151, and drives the motor 151.
(S9) Next, it is confirmed whether or not the interpolation of the interpolation command D is completed. If completed, the process returns to the timer interrupt activation wait (S1) again.
(S10) Wait for timer interrupt activation if incomplete,
(S11) After timer interrupt activation,
(S5) A speed is generated, and the following steps (S5) to (S9) are repeated.
If any error is detected at any stage of (S4) to (S9), the motion controller 101 stops the control of the motor 151, but the procedure is omitted in the flowchart of FIG. ing.
Since the above operations are the same in any of the motion controllers 101 to 104, the axis command generation units 121 to 124 are synchronized with each other, and the axis control units 131 to 134 are also configured to perform simultaneous multi-axis interpolation control of the synchronous distributed motion control system. It becomes possible.

FIG. 4 is a timing chart showing the operation timing of the second control method of the distributed motion control system of FIG. Since the operations of the motion controllers 101 to 104 are all the same, a description will be given using the motion controllers 101 and 102 as representatives.
First, when the communication processing unit 111 detects a stop signal, it transmits a stop event to another motion controller 102 at the next transmission timing. In the motion controller 102, when the communication processing unit 112 receives a stop event, both of the axis command generation units 121 and 122 input a stop event at an axis command generation cycle T1, and execute an axis command generation process. At this time, since the axis command generation periods T1 of the axis command generation units 121 and 122 are synchronized, the interpolation processing can be temporarily stopped along the trajectory of the interpolation command D.
In the above description, the interpolation process stop event is used as an example of the event. However, according to the gist of the present invention, the event is not limited to this, and may be any other event.

According to the present invention, even when a communication line having the same communication performance as the conventional one is used, the number of axes capable of synchronous interpolation control can be increased as compared with the conventional configuration. It can be applied to a system that performs coordinated control of a plurality of articulated robots.

Block diagram showing the configuration of a distributed motion control system implementing the method of the present invention Timing chart showing the operation timing of the first embodiment of the method of the present invention. Flow chart showing control algorithm of motion controller Timing chart showing the operation timing of the second embodiment of the method of the present invention Conceptual diagram of a conventional numerical control device

Explanation of symbols

100 communication line, 101-104 motion controller,
111-114 communication processing unit, 121-124 axis command generation unit,
131-134 Axis control unit, 151-154 Motor

Claims (2)

A motion controller comprising a communication processing unit connected to a communication line and supporting synchronous communication, an axis command generation unit for generating an axis command, and an axis control unit for controlling the motor in response to the axis command is paired with the motor. Multiple distributed motion control systems,
A control method for a distributed motion control system, wherein each motion controller operates according to the following procedure, and performs synchronous interpolation control of the motor based on an interpolation command.
(1) The communication processing unit inputs an interpolation command in synchronization with the communication processing unit of another motion controller.
(2) The axis command generation unit inputs the interpolation command in synchronization with an axis command generation unit of another motion controller, and generates an axis command for driving the motor.
(3) The axis control unit inputs the axis command in synchronization with the axis control unit of another motion controller, and drives the motor.
(4) The axis command generation unit operates in synchronization with the axis command generation unit of another motion controller, and the axis control unit operates in synchronization with the axis control unit of another motion controller. 2. The method of controlling a distributed motion control system according to claim 1, wherein when the motion controller detects an event, the motion controller operates according to the following procedure.
(1) The communication processing unit inputs the event and transmits the event to another motion controller through the synchronous communication.
(2) A communication processing unit of another motion controller receives the event through the synchronous communication.
(3) Communication processing units of other motion controllers input the event in synchronization.
(4) The axis command generation unit of each motion controller operates in synchronization with the input event.

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