JP2009020547A - Distributed motion control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distributed motion control system that implements synchronous control of a plurality of motors by sending control commands with no absolute time attached from a controller by asynchronous communication system. <P>SOLUTION: The controller broadcasts parameter acceleration data, parameter increased acceleration data, parameter position command data or parameter speed command data to each servo amplifier by asynchronous communication system after sending shape command data to each servo amplifier, and each servo amplifier processes the received shape command data, and parameter acceleration data, parameter increased acceleration data, parameter position command data or parameter speed command data at a timing determined by a synchronization signal to implement synchronous control of each motor. The controller can thus implement synchronous control of the motor group by asynchronous communication system without creating absolute time command data. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motion control system in which motors used in a robot or the like are connected via a network and a plurality of motors operate in synchronization.

  2. Description of the Related Art Conventionally, in industrial machines such as machine tools and robots, a motion control system in which a motion controller and a plurality of servo amplifiers are connected via a network and the motion controller operates a plurality of servo motors in synchronization is a common configuration.

  In recent years, motion controllers using personal computers have been proposed against the background of higher performance and lower prices of personal computers (hereinafter referred to as “personal computers”). In particular, a motion controller using a non-real-time operating system (hereinafter referred to as “non-real-time OS”) such as a Microsoft Windows operating system (hereinafter referred to as “Windows”) operating on a personal computer has attracted attention. .

  Previously, motion controllers and numerical control devices using Windows have been developed, but an extension board that serves as a communication interface with a numerical control and servo amplifier is installed in a personal computer, and this command data is sent to the servo amplifier. The configuration and processing were performed such as creating on the expansion board and sending to the servo amplifier.

However, this configuration requires a dedicated expansion board to be attached to the PC, and the expansion board cannot be used due to the difference in the PC shape (desktop type or notebook type), and all slots for the expansion board have been used. In the case of, there was a problem that an additional expansion board could not be added.
In order to solve this problem, there has been proposed a motion control system that enables motion control simply by installing a Windows application for motion control using an interface provided in a personal computer as a standard.

  As an example of such a motion control system, Patent Document 1 discloses a numerical control system using a LAN. In Patent Document 1, a personal computer having an asynchronous communication function and a servo amplifier having a function of asynchronous communication and a function of processing absolute time command data representing the processing time of each motor are connected by a communication line. .

  FIG. 7 is a block diagram showing the configuration of the numerical control system of Patent Document 1 (see Patent Document 1). In FIG. 7, a personal computer 710 as a computer device has an asynchronous communication function with a CPU, a memory such as a hard disk as an external storage device, and a network such as a LAN.

  The plurality of servo amplifiers 730 to 73N control the corresponding servo motors 740 to 74N, and have a synchronous interpolation control function using absolute time and an asynchronous communication function with a network such as a LAN.

  The switching hub 720 is a device that includes a switching circuit and is generally provided to enable dedicated communication between two devices in a network such as a LAN.

  The numerical control system shown in FIG. 7 has a configuration in which a personal computer 710 and a plurality of servo amplifiers 730 to 73N are connected via a switching hub 720 disposed on a LAN 715 as a network, for example. On the LAN 715, asynchronous communication using, for example, TCP / IP is performed.

  The servo amplifiers 730 to 73N are connected by a hot line 780 that notifies an emergency stop or the like.

  FIG. 8 is a block diagram showing the configuration of the servo amplifier in the numerical control system of Patent Document 1 (see FIG. 3 on page 12 of Patent Document 1). The servo amplifiers 730 to 73N have the same configuration. In FIG. 8, the servo amplifier 730 is taken up as a representative.

  In FIG. 8, a servo amplifier 730 is a servo amplifier CPU 810 that realizes a function as an axis control unit, a LAN interface circuit 830 that transmits and receives signals via the LAN 715, takes in servo amplifier communication data 870 from the LAN 715, and the like. A servo motor rotation control circuit 840 that rotates the servo motor 740 and an internal timer 850 that indicates absolute time are connected via an internal bus. A communication data buffer memory 880 is connected to the LAN interface circuit 30 in order to temporarily store communication data.

  In addition, an I / O interface circuit 860 that transmits and receives signals via the hot line 780 is provided. A signal (internal signal) of the hot line 780 includes a synchronization time correction signal 820.

  Next, the operation of each servo amplifier will be described with reference to FIG. When absolute position command data {data IDn, control axis number AX1n, absolute time command T, position command F} is received from LAN 715, it is temporarily stored in communication data buffer memory 880. Next, the absolute position command data is read from the communication data buffer memory 880, the coincidence / mismatch between the absolute time command data T and the real time data t of the internal timer 850 is compared, and it is determined whether or not T = t. The process is interrupted until T = t, and when T = t, the servo motor rotation speed is calculated based on the absolute position command data, and the servo motor drive current is controlled to rotate the servo motor. . Thus, the servo motor can be rotated while synchronizing the plurality of servo amplifiers 730 to 73N.

  When the I / O interface circuit 860 receives the synchronization time correction signal 720 through the hot line 780, the absolute time between the servo amplifiers 730 to 73N is adjusted by correcting the time of the internal timer 850.

  As described above, according to this embodiment, the personal computer 710 transmits the absolute time command to the plurality of servo amplifiers 730 to 73N by asynchronous communication via the LAN 715. Synchronous interpolation control can be performed.

  This method is considered in a motion control system configured to use two axes of servo motors. A method for realizing the electronic cam function with this configuration will be described. The electronic cam function is a path table operation in which each axis of the machine controlled by the numerical control device operates synchronously. The position information of the control axis is provided in the memory corresponding to the reference axis position. Realization means for storing in the path table operation data table and performing the synchronous operation of each control axis with the reference axis based on the information stored in the data table is already known (for example, see Patent Document 2). .

In the motion control system including the servo motors M1 and M2, with respect to the virtual master axis A, the servo motor M1 and the servo motor M2 are slave axes, and the displacement X1 of the servo motors M1 and M2 with respect to the phase θ of the virtual master axis A , X2 are expressed as follows using the respective cam curves F1, F2.
X1 = F1 (θ)
X2 = F2 (θ)

And the phase θ of the virtual master axis A at time t is θ = θ (t)
In this case, the numerical controller calculates position commands X1 (t) and X2 (t) for the servo motors M1 and M2 at time t as follows.
X1 (t) = F1 (θ (t))
X2 (t) = F2 (θ (t))

When this position command is transferred from the personal computer to the servo amplifier by the conventional method, the absolute position command data transmitted from the personal computer 710 to the servo amplifiers 730 to 73N is respectively transmitted to the data processed in each control cycle by the servo amplifiers 730 to 73N. for,
・ Data ID: k (k = 1 ... N: natural number)
・ Control axis number: AX1n
・ Absolute time command: Tk (unit: millisecond)
・ Position command: Pn (unit: micrometer)
It becomes.
JP 2004-110359 A (page 11, FIG. 1) JP 11-110047 (3rd page, FIG. 2)

  However, when the method of claim 1 of Patent Document 1 is used, since absolute position command data for each control cycle is transmitted from the controller, the amount of data flowing on the LAN 715 is large, communication traffic increases, and system performance is adversely affected. There was a problem of affecting.

  The present invention has been made in view of such problems, and provides a motion control system that synchronously controls a plurality of servo amplifiers while transmitting command data that does not give absolute time from a controller in an asynchronous communication system. For the purpose.

  In order to solve the above problem, the present invention is configured as follows.

The invention according to claim 1 is a distributed motion control system in which a controller and a plurality of servo amplifiers are connected by a communication line.
The controller includes means for transmitting shape command data indicating the shape of a curve to be interpolated and parameter acceleration command data indicating acceleration with respect to time of the parameter of the curve to the plurality of servo amplifiers,
The servo amplifier includes a communication interface that receives a synchronization signal broadcast on the communication line and generates a count-up event, a timer that generates a start event for an axis controller, the shape command data, and the parameter acceleration An asynchronous communication unit that receives command data, and an axis control unit that controls the servo motor based on the shape command data and the parameter acceleration command data are provided.

  According to a second aspect of the invention, in the first aspect of the invention, the controller broadcasts parameter jerk command data to the servo amplifier in place of the parameter acceleration command data, and the servo amplifier The parameter jerk command data is received instead of the parameter acceleration command data.

  According to a third aspect of the present invention, in the first aspect of the invention, the controller broadcasts the parameter position command data to the servo amplifier in place of the parameter acceleration command data, and the servo amplifier Parameter position command data is received instead of the parameter acceleration command data.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the controller broadcasts parameter speed command data to the servo amplifier in place of the parameter acceleration command data, and the servo amplifier Parameter speed command data is received instead of the parameter acceleration command data.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the controller generates the synchronization signal.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the one servo amplifier generates the synchronization signal.

The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the controller includes the shape command data, the parameter position command data, the parameter speed command data, and the parameter acceleration command. Means for transmitting a plurality of sets of motion command data composed of data or the parameter jerk command data to the plurality of servo amplifiers, and means for simultaneously transmitting control start command data to the servo amplifiers ,
The servo amplifier includes a buffer for storing the motion command data, and includes means for waiting for processing of the motion command data until confirmation of reception of the control start command data.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the communication line is an IEEE 1394 serial bus.

According to the invention according to any one of claims 1 to 4,
After each amplifier receives one of the parameter acceleration command data, parameter jerk command data, parameter position command data, or parameter speed command data sent simultaneously by the controller using asynchronous communication, In order to process each received shape command data and realize synchronous control between each motor, the controller uses the asynchronous communication method to synchronously interpolate multiple motor groups without creating absolute time command data Can be controlled.

  According to the fifth or sixth aspect of the invention, each servo amplifier can operate based on the synchronization signal generated by the controller or one servo amplifier.

  According to the seventh aspect of the present invention, a plurality of motion command data are stored in the servo amplifier even when motion control for seamlessly connecting a plurality of continuous shape command data has to be performed. By starting control of a plurality of servo amplifiers simultaneously using a control start command as a trigger, each servo amplifier can process a plurality of shape command data continuously without interruption in synchronism.

  According to the eighth aspect of the present invention, the IEEE 1394 serial bus can be used as a communication line, and other IEEE 1394 standard equipment (for example, a digital video camera) and an amplifier can be connected to the same IEEE 1394 serial bus. It is possible to simultaneously control an amplifier and other devices conforming to the IEEE 1394 standard from a single controller.

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

  FIG. 1 is a block diagram showing a configuration of a distributed motion control system in the first embodiment of the present invention. In each embodiment of the present invention, a servo motor is used as a motor, a servo amplifier is used as an amplifier, and an IEEE 1394 communication line is used as a communication line, but it goes without saying that the present invention is not limited to this. In FIG. 1, reference numeral 100 denotes a controller that creates commands to the servo amplifiers 101 to 10N. The servo amplifiers 101 to 10N are connected to the controller 100 through the IEEE 1394 communication line 120 and communicate with each other by an asynchronous communication method. According to the IEEE 1394 standard (see IEEE Std 1394-1995, IEEE Standard for a High Performance Serial Bus), an asynchronous communication method, that is, an asynchronous transfer function and a synchronous communication method, that is, an isochronous transfer function can be used simultaneously on one IEEE 1394 communication line. is there.

  Here, the controller 100 transmits the shape command data Pi 131 to 13N to the servo amplifiers 101 to 10N, and simultaneously transmits the parameter command data 121 to all the servo amplifiers 101 to 10N. Here, the parameter command data means any one of parameter position command data, parameter speed command data, parameter acceleration command data, and parameter jerk command data.

For example, consider that the controller 100 performs electronic cam control using two servo amplifiers 101 and 102, as exemplified in the section of the prior art.
First, the phase θ of the virtual master axis A at time t and the displacements X1 and X2 of the servo motors 101 and 102 with respect to θ are obtained using the cam curves F1 and F2, respectively.
θ = θ (t)
X1 = F1 (θ)
X2 = F2 (θ)
Is expressed.

In general, constant speed, constant acceleration, quintic curve, cycloid, single string, deformed trapezoid, deformed sine, deformed constant speed, trapecloid, inverse trapecloid, spline curve, etc. are used as cam curves. This curve is also applicable.
Here, for example,
F1: Cycloid F2: A quintic curve.

Also, the phase θ (t) is usually a curve that takes into account the speed and acceleration of the shaft, and the shape shown above can be applied as the cam curve.
Here, in order to simplify the explanation, it is assumed that the following constant acceleration linear motion is used.
θa (t) = A, (0 ≦ t ≦ t0) (execution time: t0)
θa (t) = 0, (t0 ≦ t ≦ t0 + t1) (execution time: t1)
θa (t) = − A, (t0 + t1 ≦ t ≦ t0 + t1 + t2) (execution time: t2)

Here, the velocity, acceleration, and jerk of the phase θ (t) are expressed as θv (t), θa (t), and θj (t), respectively. That is,
θv (t) = dθ (t) / dt
θa (t) = dθv (t) / dt
θj (t) = dθa (t) / dt
It becomes.

In this example, description will be made using parameter acceleration data as parameter command data in accordance with the above phase shape.
First, the breakdown of the shape command data P1 131 and P2 132 and the parameter acceleration command data 121 transmitted from the controller 100 to the servo amplifiers 101 and 102 is the shape command data P1:
(1) Shape type: 4
(2) Coefficient 1: a
(3) Coefficient 2: b
Shape command data P2:
(1) Shape type: 3
(2) Coefficient 1: a
(3) Coefficient 2: b
(4) Coefficient 3: c
(5) Coefficient 4: d
(6) Coefficient 5: e
(7) Coefficient 7: f
Parameter acceleration command data:
(1) Number of data: 3
(2) Data ID: 1
Command data type: 3
Shape type: 1
Factor 1: A
Execution time: t0
(3) Data ID: 2
Command data type: 3
Shape type: 1
Coefficient 1: 0
Execution time: t1
(4) Data ID: 3
Command data type: 3
Shape type: 1
Factor 1: -A
Execution time: t2
It becomes.

However, the shape type index of the shape command data and the mathematical formulas and coefficients related to each shape are as shown in FIG.

Further, the index of the type of parameter command data is as shown in FIG.

The quantity of transmitting the shape command data P1 131, P2 132 and the parameter acceleration command data 121 as described above from the controller 100 to the servo amplifiers 101 and 102 is as follows.
Shape command data: 2 (number of servo amplifiers)
Parameter acceleration data: 1 (broadcast transmission)
Thus, unlike the prior art, it is not necessary to sequentially transmit a large amount of absolute position command data for each control cycle.

  The servo amplifiers 101 to 10N are also connected to each other by the IEEE 1394 communication line 120, but the servo amplifiers 101 to 10N are synchronized by receiving a cycle start packet having a fixed period. In the IEEE 1394 network, a communication node called a cycle master outputs a cycle start packet to the network at a constant period, and other communication nodes correct the clock of each communication interface using cycle time data included in the cycle start packet. Is equipped.

  Here, it is assumed that the servo amplifier 10N is a transmission source of the cycle start packet and transmits the cycle start packet to the other servo amplifiers 101 to 10 (N−1) at a constant period. Reference numerals 111 to 11N denote servo motors which are controlled by servo amplifiers 101 to 10N.

  FIG. 2 is a block diagram showing the configuration of the servo amplifier 101 in the first embodiment of the present invention. Since the other servo amplifiers 102 to 10N are the same, the description thereof is omitted here. In FIG. 2, reference numeral 201 denotes a communication interface of the servo amplifier 101, which can process both the cycle start packet 205 and the asynchronous communication method. The communication interface 201 transmits a cycle start packet 205 to the IEEE 1394 communication line 120 at a constant period, and simultaneously generates a count-up event 206.

  After receiving the count-up event 206, the timer 203 increases the count if the count value set in advance is not reached, and displays the activation event registered in advance when the count value set in advance is reached. Generate and reset the count value. For example, if the cycle of the cycle start packet is 125 μsec and it is desired to start the axis control unit 204 at a cycle of 500 μsec, the start event 207 that causes the timer 203 to start the axis control unit 204 with a count value of 4 (= 500/125). Register. As a result, the axis control unit 204 is activated at the set cycle.

  Reference numeral 202 denotes an asynchronous communication unit that receives the shape command data P1 131 and the parameter command data 121 transmitted by the controller 100 and outputs them to the axis control unit 204. The axis control unit 204 inputs the shape command data P1 131 and the parameter command data 121, selects the process specified by the shape type of the shape command data, and controls the servo motor 111 based on the parameter acceleration command data 121. To do. The axis control unit 204 is activated by the activation event 207 from the timer 203 as described above.

  Regarding the activation event 207, as described above, when the axis control unit 204 needs to be activated every cycle T1, an activation event issued for each cycle T1 is registered in the timer 203 in advance, and this corresponds to the set cycle. The activation event 207 is issued at the time to be executed. Since the time of the timer 203 is synchronized with the other servo amplifiers 102 to 10N, when the issuing time of the start event 207 is set to be the same for all the servo amplifiers 101 to 10N, all the servo amplifiers 101 to 10N are set. These axis control units are activated in synchronization, and synchronous interpolation control of the servo motors 111 to 11N becomes possible.

  FIG. 6 shows these synchronization timings. In the IEEE 1394 network 601, the servo amplifier 101 serving as the cycle master transmits a cycle start packet 603 every 125 μs synchronous cycle 602. At this time, if the communication packet has a small amount of data that can be broadcast simultaneously in the synchronization cycle 602, all servo amplifiers can complete the data reception by the time the cycle start packet 603 is received. As a result, each servo amplifier can start processing simultaneously while receiving data in the asynchronous communication system.

  For example, the controller writes the shape command data P1 131 in the transmission buffer of the IEEE 1394 network 601 and then transmits it to the IEEE 1394 network 601. On the servo amplifier side, the asynchronous communication unit 202 receives the shape command data P1 131 at a certain time. Thereafter, the controller writes the parameter acceleration command data 121 for broadcast transmission into the transmission buffer of the IEEE 1394 network 601, and then broadcasts to the IEEE 1394 network 601. On the servo amplifier side, a start event 207 is generated in the first synchronous cycle 602 after the broadcast parameter acceleration command data 121 is received by the asynchronous communication unit 202, the axis control unit 204 is started, and all servos The amplifiers 101 to 10N perform synchronous interpolation control of the plurality of servo motors 111 to 11N at the same timing.

  FIG. 3 is a flowchart showing a processing procedure of the axis control unit 204 of the servo amplifier 101 in the first embodiment of the present invention. First, the axis control unit 204 waits for an activation event from the timer 203 when processing is started (ST301). When the activation event 207 is received, it is confirmed whether or not the shape command data P1 131 is received on the reception buffer of the communication interface 201 (ST302), and if received, the activation event waits for receiving the parameter command data 121 ( If not received, the process waits for an activation event for receiving the shape command data P1 131 (ST301).

When a start event 207 is received while waiting for a start event (ST303), it is confirmed whether or not the parameter command data 121 is received on the reception buffer of the communication interface 201 (ST304). The process waits for a start event (ST305), and if not received, waits for a start event for receiving the parameter command data 121 (ST303).
When the activation event 207 is received while waiting for the activation event (ST305), the current parameter position θ (t + Δt) is calculated in the following procedure.

First, the command data type of the shape parameter data is determined (ST306).
Next, the type of parameter command data is determined.
First, it is determined whether it is jerk (ST307). If it is jerk, parameter jerk is calculated (ST308), and if it is not jerk, it is determined whether it is acceleration (ST309). If it is an acceleration, a parameter acceleration is calculated (ST311), and if it is not an acceleration, it is determined whether it is a speed (ST310). If it is speed, the parameter speed is calculated (ST312). If it is not speed, the parameter position is calculated (ST313).

In this embodiment, since the command data type is acceleration data, parameter acceleration is calculated through ST307 and ST309 (ST311). Here, the shape function designated by the shape type is selected. From the shape command data P1 131 and the parameter acceleration command data 121, the acceleration θa (t) of the parameter θ at time t is
θa (t) = A, (0 ≤ t ≤ t0) (execution time: t0)
θa (t) = 0, (t0 ≤ t ≤ t0 + t1) (execution time: t1)
θa (t) = -A, (t0 + t1≤t≤t0 + t1 + t2) (execution time: t2)
(ST311).

These are integrated to obtain the parameter speed θv (t) as follows (ST312).
v (t) = A * t, (0 ≤ t ≤ t0)
v (t) = v (t0), (t0 ≤ t ≤ t0 + t1)
v (t) = v (t1)-A (t-t0-t1), (t0 + t1≤t≤t0 + t1 + t2)

Finally, these are integrated to obtain the parameter position θ (t) as follows (ST313).
θ (t) = A * t 2/2, (0 ≦ t ≦ t0)
θ (t) = u (t0) + A * t0 (t-t0), (t0 ≤ t ≤ t0 + t1)
θ (t) = u (t1 ) + A * t0 (t-t0-t1) -A (t-t0-t1) 2/2, (t0 + t1 ≦ t ≦ t0 + t1 + t2)

  Then, a position F1 (θ (t + Δt)) on the given curve F1 (θ) is calculated (ST314), and position control is performed with F1 (θ (t + Δt)) as a target position (ST315). Then, it is confirmed whether or not the execution time described in the parameter acceleration command data 121 has expired (ST316). If it has expired, a series of processing is terminated, and if not, waiting for a start event for motor control ( ST305).

Specifically, in the present embodiment, since the shape command data for the servo amplifiers 101 and 102 is a cycloid and a quintic curve, respectively, the motor positions X1 and X2 of the servo amplifiers 101 and 102 are respectively
X1 = a−b * COS (θ (t + Δt))
X2 = a * (θ (t + Δt)) ^ 5
+ b * (θ (t + Δt)) ^ 4
+ c * (θ (t + Δt)) ^ 3
+ d * (θ (t + Δt)) ^ 2
+ e * (θ (t + Δt)) + f
It becomes.

  When the command data type is parameter jerk, the motor command can be calculated in the same manner by providing means for integrating the parameter jerk to obtain the acceleration.

For example, in the same shape as the shape command data described above, the jerk θj (t) of the parameter θ at time t is
θj (t) = J, (0 ≤ t ≤ t01)
θj (t) = 0, (t01 ≦ t ≦ t01 + t02)
θj (t) = -J, (t01 + t02 ≦ t ≦ t01 + t02 + t03)
If so, the parameter jerk command data is as follows.
(1) Number of data: 3
(2) Data ID: 1
Command data type: 4
Shape type: 1
Factor 1: J
Execution time: t01
(3) Data ID: 2
Command data type: 4
Shape type: 1
Coefficient 1: 0
Execution time: t02
(4) Data ID: 3
Command data type: 4
Shape type: 1
Factor 1: -J
Execution time: t03

After receiving the parameter jerk command data (ST304), the servo amplifier 101 receives the parameter jerk θj (t) = J, (0 ≦ t ≦ t01)
θj (t) = 0, (t01 ≦ t ≦ t01 + t02)
θj (t) = -J, (t01 + t02 ≦ t ≦ t01 + t02 + t03)
To obtain the parameter acceleration θa (t) as follows (ST311).
θa (t) = J * t, (0 ≤ t ≤ t01)
θa (t) = a (t01), (t01 ≦ t ≦ t01 + t02)
θa (t) = a (t01 + t02)-J (t-t01-t02), (t01 + t02≤t≤t01 + t02 + t03)
Hereinafter, since the means for obtaining the parameter speed and the parameter position are as described above, the description thereof is omitted here.

  By using the configuration and means described above, the parameter command data that the controller broadcasts simultaneously in the asynchronous communication method is received by each servo amplifier at a common synchronization timing between the servo amplifiers. In order to execute shape command data and realize synchronous interpolation control between servo motors, the controller can perform synchronous interpolation control of multiple motor groups using the asynchronous communication method without creating absolute time command data. Can do.

  FIG. 4 is a block diagram showing the configuration of the servo amplifier in the second embodiment of the present invention. The difference from FIG. 2 is that the communication interface 201 and the asynchronous communication unit 402 are processing the control start command 401 and that a buffer 404 for storing the shape command data P1 131 and the parameter command data 121 is provided. Since other processes and data are exactly the same as those in FIG. 2, description thereof is omitted here.

  FIG. 5 is a flowchart showing a processing procedure of the axis control unit 205 of the servo amplifier 101 in the second embodiment of the present invention. The difference from FIG. 3 is that a step of confirming whether or not a control start command is received on the reception buffer of the communication interface 201 (ST501), and whether or not the shape command data P1 131 and parameter command data 121 are present in the buffer 404. The step of confirming (ST502) and the step of extracting the data (ST503) are added. The other steps are exactly the same as in FIG.

  By adopting the means described above, even when it is necessary to perform motion control for connecting a plurality of continuous shape command data without interruption, a plurality of motion command data is stored in the servo amplifier. By starting the control of the plurality of servo amplifiers simultaneously using the control start command as a trigger, the servo amplifiers can process the plurality of shape command data continuously without interruption in synchronization.

  According to the present invention, it is possible to construct a motion control system that synchronously controls servo motor groups using a general-purpose personal computer equipped with a non-real-time OS such as Windows or Linux and having an IEEE1394 interface as a controller.

  Therefore, the present invention can be applied to a system for controlling a servo amplifier or a digital video camera, such as a monitoring device or a home automation system, by installing software on a general-purpose personal computer without using special hardware.

The block diagram which shows the structure of the distributed motion control system in 1st Example of this invention. The block diagram which shows the structure of the servo amplifier in 1st Example of this invention. The flowchart which shows the process sequence of the axis | shaft control part of the motor drive in 1st Example of this invention. The block diagram which shows the structure of the servo amplifier in 2nd Example of this invention. The flowchart which shows the process sequence of the axis | shaft control part of the motor drive in 2nd Example of this invention. The timing chart which shows the transmission / reception timing of the data in 1st Example of this invention Block diagram showing the configuration of a conventional numerical control system Block diagram showing the configuration of a servo amplifier in a conventional numerical control system Shape type index of shape command data and mathematical formulas and coefficients for each shape Parameter command data type index

Explanation of symbols

100 Controller 101 to 10N Servo amplifier 111 to 11N Servo motor 120 IEEE 1394 communication line 121 Parameter command data 131 to 13N Shape command data 140 IEEE 1394 hub 201 Communication interface 202 Asynchronous communication unit 203 Timer 204 Axis control unit 205 Cycle start packet 206 Count up event 207 Start event 401 Control start command 402 Asynchronous communication unit 403 Axis control unit 404 Buffer 601 IEEE 1394 network 602 Synchronization cycle 603 Cycle start packet 710 Personal computer 715 LAN
720 Switching hub 730-73N Axis controller (servo amplifier)
740-74N Servo motor 7780 Hotline 810 Servo amplifier CPU
820 Synchronization time correction signal 830 LAN interface circuit 840 Servo motor rotation control circuit 850 Internal timer 860 I / O interface circuit 870 Servo amplifier communication data 880 Communication data buffer memory

Claims (8)

In a distributed motion control system in which a controller and multiple servo amplifiers are connected via communication lines,
The controller includes means for transmitting shape command data indicating the shape of a curve to be interpolated and parameter acceleration command data indicating acceleration with respect to time of a parameter of the curve to the plurality of servo amplifiers,
The servo amplifier includes a communication interface that receives a synchronization signal broadcast on the communication line and generates a count-up event, a timer that generates a start event for an axis control unit, the shape command data, and the parameter acceleration A distributed motion control system comprising: an asynchronous communication unit that receives command data; and an axis control unit that controls the servo motor based on the shape command data and the parameter acceleration command data.   The controller broadcasts parameter jerk command data instead of the parameter acceleration command data to the servo amplifier, and the servo amplifier receives parameter jerk command data instead of the parameter acceleration command data. The distributed motion control system according to claim 1.   The controller broadcasts parameter position command data to the servo amplifier in place of the parameter acceleration command data, and the servo amplifier receives the parameter position command data instead of the parameter acceleration command data. The distributed motion control system according to claim 1.   The controller broadcasts parameter speed command data instead of the parameter acceleration command data to the servo amplifier, and the servo amplifier receives parameter speed command data instead of the parameter acceleration command data. The distributed motion control system according to claim 1.   The distributed motion control system according to claim 1, wherein the controller generates the synchronization signal.   The distributed motion control system according to claim 1, wherein one of the servo amplifiers generates the synchronization signal. The controller includes a plurality of sets of motion command data including the shape command data, the parameter position command data, the parameter speed command data, the parameter acceleration command data, or the parameter jerk command data. Means for transmitting to the amplifier, and means for simultaneously transmitting control start command data to the servo amplifier,
The servo amplifier includes a buffer for storing the motion command data, and includes means for waiting for processing of the motion command data until confirmation of receipt of the control start command data. Item 7. The distributed motion control system according to any one of items 6 to 9.   8. The motion control system according to claim 1, wherein the communication line is an IEEE 1394 serial bus.

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