TW201445266A - Synchronous control system and synchronous control method - Google Patents

Abstract

A synchronous control system and a synchronous control method are disclosed. The synchronous control system includes a plurality of rotary shafts, a plurality of motors, a plurality of driver and a plurality of controller. Each of the controllers generates an asynchronous rotary instruction or a synchronous rotary instruction. Each of the controllers controls the corresponding motor to rotate asynchronously or synchronously with the remaining motors according to the asynchronous rotary instruction or the synchronous rotary instruction. Then, each of the motors drives the corresponding rotary shaft to rotate asynchronously or rotate synchronous. The synchronous control system and the synchronous control method of the present invention are capable of selecting to implement synchronous operations or asynchronous operations.

Description

Synchronous control system and synchronous control method

The present invention relates to a control system, and more particularly to a synchronous control system and a synchronous control method.

The principle of the motor is generally that a controller generates a control signal to a driver, and the driver controls the rotation of the rotating shaft through a motor according to the control signal.

In a system of multiple rotating shafts, such as a conveyor system of a production line, which includes a plurality of conveying units, each conveying unit includes the above-mentioned controller, driver, motor and rotating shaft, however, when each conveying unit needs to be synchronized, that is, it is required When the rotation axes of the respective conveying units are synchronized, only the rotation axes of all the conveying units can be synchronized, and the partial rotation axes cannot be selected for synchronization, and the other part of the rotation axes are not synchronized.

In addition, in the case where one rotating shaft is already rotating and the other rotating shaft is stationary, the prior art cannot perform the operation of synchronously rotating the two rotating shafts, or in the case where the two rotating shafts have been synchronously rotated, it is necessary to Continuous synchronization, unable to switch to out of sync midway, so the application is limited.

Therefore, it is necessary to propose a solution to the synchronization problem of the above-described multi-rotation axis.

It is an object of the present invention to provide a synchronous control system and a synchronous control method that can select for synchronous or asynchronous operation at any time.

In accordance with the above purposes, the present invention discloses a synchronous control system including a plurality of rotating shafts, a plurality of motors, a plurality of drivers, and Multiple controllers. Each axis of rotation is used to generate a rotation angle signal. Each motor is coupled to one of the rotating shafts. Each driver is electrically coupled to one of the motors. Each controller is operative to generate a non-synchronous rotation command or a synchronous rotation command. When each controller generates a non-synchronous rotation command, each corresponding driver controls the corresponding motor to rotate asynchronously with the other motor according to the asynchronous rotation command, and then the corresponding motor drives the corresponding rotating shaft and the other rotating shafts. Non-synchronous rotation. When the controller generates the synchronous rotation command, each corresponding driver controls the corresponding motor to rotate synchronously with the other motors according to the synchronous rotation command, and then the corresponding rotating shaft synchronizes with the other rotating shafts by the corresponding motors. Turn.

Another object of the present invention is to provide a synchronous controller The method is used for a synchronous control system. The synchronous control system includes a plurality of rotating shafts, and a plurality of motors are respectively coupled to one of the rotating shafts, and the plurality of drivers are electrically coupled to one of the motors. And a plurality of controllers are respectively electrically coupled to one of the drivers, the synchronization control method includes: (A) initializing the controllers; (B) selecting, by each controller, synchronous rotation or non-synchronous rotation, selecting non- When synchronously rotating, proceed to step (C), select synchronous rotation, enter step (D); (C) each controller generates a non-synchronous rotation command, enter step (E); (D) each controller selects to synchronize The target generates a synchronous rotation command, and proceeds to step (F); (E) the driver corresponding to each controller controls the corresponding motor to rotate asynchronously with the other motor according to the asynchronous rotation command, and then the corresponding motor drives the corresponding rotating shaft And (F) the corresponding driver of the controller controls the corresponding motor to rotate synchronously with the other motor according to the synchronous rotation command, and then drives the corresponding rotation by the corresponding motor. Axis and the other rotational shaft is rotated synchronously.

The synchronous control system and the synchronous control method of the invention can be used at any time Select to perform synchronous or asynchronous operation, and achieve simultaneous synchronization of multiple rotating axes.

100, 102, 104‧‧‧ controller

110, 112, 114‧‧‧ drive

120, 122, 124‧‧ ‧ motor

130, 132, 134‧‧‧ rotating shaft

140, 142, 144‧‧‧ load

180‧‧‧Transmission mechanism

190‧‧‧Signal sensor

600‧‧‧tetragonal conveyor

602, 604, 606, 608‧‧‧ conveyor

1000‧‧‧Synchronous selection unit

1002‧‧‧ asynchronous rotation command generation unit

1004‧‧‧Synchronous rotation command generation unit

1006‧‧‧Signal selection unit

1008‧‧‧virtual token generation unit

1010‧‧‧Synchronous target selection unit

1012‧‧‧Preprocessing logic unit

C1, C2, C3‧‧‧ rotation instructions

R1, R2, R3‧‧‧ rotation angle signal

R1', R2', R3'‧‧‧ rotation angle signal after signal selection unit

V1, V2, V3‧‧‧ virtual marks

S700-S770‧‧‧Steps

Fig. 1 is a diagram showing a synchronous control system and a load driven by the synchronous control system according to an embodiment of the present invention.

Figure 2 is a schematic diagram showing the principle of synchronization in accordance with the present invention.

Figure 3 is a schematic diagram showing the creation of a virtual token of the present invention.

Figure 4 is a diagram showing another generation of virtual tokens of the present invention.

Figure 5 is a block diagram showing the controller of Figure 1 and its connection to other components.

Fig. 6 is a view showing a control example of the present invention for five conveyors.

Fig. 7 is a flow chart showing a synchronous control method according to the present invention.

The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.

Please refer to FIG. 1 , which shows a synchronous control system and a load driven by the synchronous control system according to an embodiment of the invention.

The synchronous control system includes a plurality of controllers 100, 102, 104, a plurality of drivers 110, 112, 114, a plurality of motors 120, 122, 124, and a plurality of rotating shafts 130, 132, 134.

The controller 100 is electrically coupled to the driver 110 for providing a control command. More specifically, a rotation command C1 is provided. The rotation command C1 can be a synchronous rotation command or a non-synchronous rotation command. The driver 110 is electrically coupled to the motor 120 for controlling the motor 120 to rotate synchronously or non-synchronously with the other motors 122 and 124 according to the rotation command C1 as a synchronous rotation command or a non-synchronous rotation command, and then the rotary shaft 130 is driven by the motor 120. Synchronous or non-synchronous rotation with the other rotating shafts 132, 134, thereby causing the rotating shaft 130 to actuate a load 140 in synchronism or non-synchronization with the other loads 142, 144. In addition, the driver 110 returns a rotation angle signal R1 generated by the rotation shaft 130 to the controller 100. Load 140 is, for example but not limited to, a conveyor on a production line.

Similarly, the controllers 102 and 104 are electrically coupled to the driver respectively. The switches 112 and 114 respectively provide rotation commands C2 and C3 to the drivers 112 and 114. The drivers 112 and 114 are electrically coupled to the motors 122 and 124, respectively, and control the rotation of the motors 122 and 124 according to the rotation commands C2 and C3, respectively. The rotation of the rotating shafts 132, 134 is driven by the motors 122, 124, and the rotating shafts 132, 134 respectively actuate the loads 142, 144. The drivers 112, 114 will feedback the rotational angle signals R2, R3 of the rotating shafts 132, 134 to the controllers 102, 104, respectively.

Please also refer to Figure 1 and Figure 2, and Figure 2 shows Schematic diagram of the synchronization principle of the present invention.

The rotation axes 130 and 132 respectively generate the rotation angle signals R1 and R2, and are respectively fed back to the controllers 100 and 102 by the drivers 110 and 112. The rotation angle signals R1 and R2 are, for example but not limited to, encoder signals. The controllers 100, 102 of the present invention can respectively generate a virtual mark V1, V2, and the virtual marks V1, V2 respectively correspond to a specific position in the rotation range of the rotating shafts 130, 132, and are synchronized by controlling the virtual marks V1, V2. The rotation axes 130, 132 are also synchronized.

Please refer to FIG. 3 , which is a schematic diagram showing the generation of a virtual mark according to the present invention. When the rotation axis 130 and the rotation angle signal R1 (such as but not limited to the encoder signal) are 1:1, that is, the rotation axis 130 rotates. When the circle is rotated, the rotation angle signal R1 is also rotated once, and the Z signal of the rotation angle signal R1 (that is, the signal generated once per rotation) can be directly used as a reference to generate the virtual mark V1, that is, the controller 100 rotates at an angle. When the signal R1 is rotated once (equal to one rotation of the rotating shaft 130), the position corresponding to the rotating shaft 130 is used as a reference for generating the virtual mark V1, and a counter is used to count a specific value after the Z signal is generated to set the virtual mark V1. Displaces to any position of the rotation range of the rotary shaft 130, and then counts 1/N (N is an integer) of one rotation by another counter, and generates a virtual mark every 1/N count, which can generate N in one turn. The evenly distributed virtual token V1. It should be noted that the Z signal is well known to those skilled in the art of motor control, and this is not to be described in detail.

Please refer to FIG. 4, which shows another virtual generation of the present invention. A schematic diagram of the symbol, when the rotating shaft 130 and the rotation angle signal R1 (such as but not limited to the encoder signal) are not 1:1, that is, between the rotating shaft 130 and the rotation angle signal R1, there is a shifting mechanism 180 (or a gear mechanism) The speed increase or deceleration indicates that the rotation angle signal R1 does not rotate one revolution when the rotation shaft 130 rotates one rotation, and therefore the Z signal of the rotation angle signal R1 (that is, the signal generated once per rotation) cannot be directly used as a reference. The method proposed by the present invention is to add a signal sensor 190 for sensing the corresponding position when the rotating shaft 130 rotates once, and the controller 100 uses the corresponding position when the rotating shaft 130 rotates once as a reference for generating the virtual mark V1. The virtual mark V1 can be displaced to any position of the rotation range of the rotary shaft 130 by using two counters as shown in FIG. 3, and N average distributed virtual marks V1 can be generated in the rotation range on the rotary shaft 130. . It is to be noted that in addition to the above-described external signal sensor 190, other methods of detecting and generating one signal per revolution can be used in the present invention.

It should be noted that the figures of Figures 3 and 4 produce virtual tokens. The formula can also be applied to the controllers 102, 104 of Fig. 1.

Please also refer to Figures 1 and 5, and Figure 5 shows the first A block diagram of the controller 100 of the figure and a schematic diagram of its connection to other components.

The controller 100 includes a synchronization selection unit 1000, which is different. The step rotation instruction generation unit 1002, a synchronous rotation instruction generation unit 1004, a signal selection unit 1006, a virtual token generation unit 1008, a synchronization target selection unit 1010, and a preprocessing logic unit 1012.

Asynchronous rotation instruction generation unit 1002 and synchronous rotation instruction The generating unit 1004 is electrically coupled to the synchronization selecting unit 1000. The synchronization selecting unit 1000 is configured to select a source of the rotation command C1. When the asynchronous rotation command generating unit 1002 is selected, the rotation command C1 is a non-synchronous rotation command, and the driver 110 drives the rotation. The independent operation of the shaft 130 is not affected by the other rotating shafts 132 and 134. When the synchronous selecting unit 1000 selects the synchronous rotating command generating unit 1004, it indicates that the rotating command C1 is a synchronous rotating command, and the rotating shaft 130 is to be rotated. At least one of the axes 132, 134 is synchronized, and the target to be synchronized is determined according to the synchronization target selection unit 1010. The synchronization target selection unit 1010 is electrically coupled to the synchronous rotation instruction generation unit 1004 for selecting the rotation to be synchronized. axis. The synchronous rotation command generating unit 1004 determines the synchronization target as at least one of the rotation axes 132, 134 according to the synchronization target selection unit 1010, and according to the rotation angle signal R1' after the signal selection unit 1006, the virtual symbol V1 (by the virtual mark) The rotation angle signal and the virtual mark of the rotation axis (for example, the rotation axis 132) to be synchronized are calculated by the generating unit 1008 to calculate an angular difference and a speed difference, and then the rotation command C1 is generated according to the angle difference and the speed difference, and the synchronization command is selected. The unit 1000 transmits the rotation command C1 to the driver 110, thereby rotating the rotation shaft 130 in synchronization with the rotation axis to be synchronized (for example, the rotation shaft 132). The angle difference can be obtained by comparing the virtual symbols, and the speed difference can be obtained by comparing the rotation angle signals, and the tracking axis to be synchronized is followed by the synchronous rotation command, so that the angle difference and the speed difference are equal to zero, that is, Synchronize. It should be noted that the rotation angle signal R1 is a signal input by the driver 110 to the signal selection unit 1006, and the rotation angle signal R1' is a signal after passing through the signal selection unit 1006, in fact, the two are the same, and different labels are only used to distinguish the input. After the signal selection unit 1006 and the signal selection unit 1006 are passed.

The virtual token generating unit 1008 is electrically coupled to the signal selection list Element 1006, virtual token V1 can be generated according to the method shown in FIG. 3, or virtual token V1 can be generated by signal sensor 190 according to the method shown in FIG. When a plurality of virtual marks V1 are generated, the angular difference and the speed difference can be recalculated as long as the virtual mark appears, and multi-point synchronization is achieved.

The signal selection unit 1006 is electrically coupled to the synchronization selection unit 1000, the driver 110 and the controllers 102, 104, may select the rotation angle signal R1 or select the rotation command C1 transmitted by the synchronization selection unit 1000 for use by the synchronous rotation instruction generation unit 1004, the virtual token generation unit 1008, and the controllers 102, 104. And then achieve synchronization in different ways.

The pre-processing logic unit 1012 is electrically coupled to the synchronization target selection unit 1010, and can pass the signal selection list transmitted by the controllers 102 and 104. The rotation angle signals R2', R3' and the virtual symbols V2, V3 after the element are pre-processed, for example, but not limited to, related information to be synchronized before being synchronized, so that synchronization can be quickly performed when synchronization is selected.

The controllers 102, 104 have the same components as the controller 100, This is not to be repeated.

It should be noted that Figures 1 and 5 are based on three controllers. For example, the invention can be applied to both controllers and more than three controllers. In addition, in FIG. 1 , the controller 100 is electrically coupled to the controller 102 , and the controller 102 is electrically coupled to the controller 104 . In FIG. 5 , the controller 100 is electrically coupled to the controller 102 , 104. In practical applications, the controllers 100, 102, and 104 may have a relationship of one to one as shown in FIG. 1 or a pair of multiple (such as a star) as shown in FIG. 5, so that not only two can be achieved. Synchronization can also achieve multiple synchronizations. In FIG. 5, the controller 100 is electrically coupled to the two controllers 102 and 104. However, the present invention can be applied to more than two controllers to achieve a one-to-many synchronization application. For example, the quadrilateral conveyor 600 in FIG. 6 needs to be connected to four conveyors 602, 604, 606, because it has four conveyors corresponding to the conveyors 602, 604, 606, and 608. The controller of 608 is used to achieve a synchronous application (which will be detailed later).

The invention can be applied to the transfer between multi-section conveyors, as each The conveyors are driven by their own motors. The conventional technology is to reserve enough length when the conveyors are to be conveyed through the two conveyors, so that the conveyor can be rotated to a stable speed before passing, otherwise there will be unnecessary speed difference. Friction phenomenon, and because of the multi-section tandem connection, it only needs to be activated when transmitting or receiving, if it has been transmitted away, it can be stopped, not all time needs to be synchronized, and the invention can be freely synchronized, suitable for such applications, and because It can refer to the rotation angle signal of the adjacent conveyor, so it can maintain the same speed, no need to reserve excess length for steady speed, and can maintain no speed difference during acceleration and deceleration, saving cost and increasing application flexibility.

Please refer to Fig. 6, which shows the invention for five conveyors. Control example.

The square conveyor 600 has a rotating function and can transport four The machines 602, 604, 606, 608 perform the transfer operation, and the direction of the arrow of the quadrilateral conveyor 600 indicates that the conveyor 602 or the conveyor 604 can be transported. If the conveyor 606 or the conveyor 608 is to be transported, the square conveyor 600 turns 90. After the degree is synchronized, in this case, the synchronization is one-to-many. The present invention can realize the selective exchange of the rotation angle signal and the virtual mark by the square conveyor 600 and the conveyors 602, 604, 606, and 608. Synchronize.

Please refer to FIG. 7, which shows the synchronous control according to the present invention. The flow chart of the method is used for a synchronous control system. The synchronous control system includes a plurality of rotating shafts, and a plurality of motors are respectively coupled to one of the rotating shafts, and the plurality of drivers are electrically coupled to the motors respectively. The first and the plurality of controllers are electrically coupled to one of the drivers, and the synchronization control method includes the following steps.

In step S700, the controllers are initialized. Due to the controller For the electronic circuit, after the power is supplied to the controller, the controller can be operated normally through initialization, including but not limited to resetting, checking or setting parameters, etc., so that subsequent operations can be performed correctly.

In step S710, each controller can select synchronous rotation according to requirements. Or asynchronous rotation. When the controller selects the asynchronous rotation, the process proceeds to step S720, and when the controller selects the synchronous rotation, the process proceeds to step S730.

In step S720, each controller generates an asynchronous rotation finger Then, the process proceeds to step S740.

In step S730, each controller selects a target to be synchronized and produces A synchronous rotation command is issued, and then proceeds to step S750. In this step, each controller generates at least one virtual mark, the virtual mark is located at a specific position in the rotation range of the corresponding rotation axis, and each controller rotates the angle signal according to one of the corresponding rotation axes, the corresponding virtual mark, The rotation angle signal of one of the other rotation axes and the virtual mark generated by the other controllers generate the synchronous rotation command.

When each rotation axis and rotation angle signal is 1:1, each control The position corresponding to each rotation axis when the rotation of the rotation angle signal is one rotation is used as a reference for generating the virtual mark.

When each rotation axis and rotation angle signal is not 1:1, each control The corresponding position when the controller rotates one rotation of each rotation axis is used as a reference for generating the virtual mark.

The virtual tokens when each controller generates a plurality of virtual tokens The average distribution is in the range of rotation of the corresponding rotation axis.

Step S740, the rotation axis corresponding to each controller is not synchronized. The rotation command performs non-synchronous rotation. More specifically, the corresponding driver controls the corresponding motor to rotate asynchronously with other motors according to the asynchronous rotation command, and then the corresponding motor drives the corresponding rotation axis to rotate asynchronously with the other rotation axes. Then, the process proceeds to step S760.

Step S750, the rotation axis corresponding to each controller is rotated according to the synchronization The rotation command performs synchronous rotation, more specifically, the corresponding driver controls the corresponding motor to rotate synchronously with the other motors according to the synchronous rotation command, and then the corresponding motor rotates the corresponding rotation shaft to rotate synchronously with the other rotation shafts, and then enters Step S770.

Step S760, whether to change to synchronous rotation, and if so, enter the step At step S730, if no, the process proceeds to step S740.

Step S770, whether it is changed to asynchronous rotation, if yes, enter Step S720, if no, the process proceeds to step S750.

It should be noted that, in the above step S740, the controller can follow The time is changed to the synchronous rotation demand, that is, the process proceeds to step S760 to determine whether to change to the synchronous rotation or to maintain the asynchronous rotation. Similarly, in the above step S750, the controller can be replaced with the asynchronous rotation requirement at any time, that is, the process proceeds to step S770. Whether to change to asynchronous rotation or to maintain synchronous rotation.

The virtual tokens when each controller generates a plurality of virtual tokens The average distribution is in the range of rotation of the corresponding rotation axis.

Although the present invention has been disclosed above with preferred embodiments, it is not To define the invention, and those of ordinary skill in the art to which the invention pertains, The scope of the present invention is defined by the scope of the appended claims, unless otherwise claimed.

100, 102, 104‧‧‧ controller

110, 112, 114‧‧‧ drive

120, 122, 124‧‧ ‧ motor

130, 132, 134‧‧‧ rotating shaft

140, 142, 144‧‧‧ load

C1, C2, C3‧‧‧ rotation instructions

R1, R2, R3‧‧‧ rotation angle signal

Claims (13)

A synchronous control system includes: a plurality of rotating shafts for respectively generating a rotation angle signal; a plurality of motors respectively coupled to one of the rotating shafts; and a plurality of drivers electrically coupled to the motors And a plurality of controllers electrically coupled to one of the drivers, wherein each controller is configured to generate a non-synchronous rotation command or a synchronous rotation command, when each controller generates the asynchronous rotation command The corresponding driver controls the corresponding motor to rotate asynchronously with the other motors according to the asynchronous rotation command, and then the corresponding motor drives the corresponding rotating shaft to rotate asynchronously with the other rotating shafts, when each controller generates the When the synchronous rotation command is issued, each corresponding driver controls the corresponding motor to rotate synchronously with the other motors according to the synchronous rotation command, and then the corresponding rotating shafts rotate synchronously with the other rotating shafts by the corresponding motors. According to the synchronous control system of claim 1, wherein each controller generates at least one virtual mark, the virtual mark is located at a specific position in a rotation range of the corresponding rotation axis, and each controller corresponds to the corresponding rotation angle signal. The virtual rotation marks, the rotation angle signals of other rotation axes, and the virtual marks generated by other controllers generate the synchronous rotation instruction. According to the synchronous control system of claim 2, wherein each controller comprises: a non-synchronous rotation instruction generation unit for generating the asynchronous rotation instruction; a synchronous rotation instruction generation unit for generating the synchronous rotation instruction; a synchronization selection unit electrically coupled to the asynchronous rotation instruction generation unit and the synchronization a rotation instruction generating unit, configured to select the asynchronous rotation instruction or the synchronous rotation instruction; a signal selection unit electrically coupled to the synchronization selection unit and the corresponding driver for selecting a corresponding rotation angle signal; a virtual token generation The unit is electrically coupled to the signal selection unit for generating the virtual token; a synchronization target selection unit is electrically coupled to the synchronous rotation instruction generation unit for selecting a rotation axis to be synchronized; and a pre-processing The logic unit is electrically coupled to the synchronization target selection unit for pre-processing the rotation angle signal and the virtual mark of the other rotation axes. According to the synchronous control system of claim 2, wherein when each of the rotation axes and the rotation angle signal is 1:1, each controller rotates one rotation of the rotation angle signal to correspond to the position of each rotation axis as the virtual mark is generated. Reference. According to the synchronous control system of claim 2, wherein when each of the rotation axes and the rotation angle signal is not 1:1, each controller rotates one rotation of each rotation axis as a reference for generating the virtual mark. According to the synchronous control system of claim 2, wherein each of the controllers generates a plurality of virtual tokens, the virtual tokens are evenly distributed in the rotation range of the corresponding rotation axis. A synchronous control method for a synchronous control system, the synchronous control system includes a plurality of rotating shafts, and a plurality of motors are respectively coupled to one of the rotating shafts, and the plurality of drivers are electrically coupled to the motors respectively And a plurality of controllers are electrically coupled to one of the drivers, respectively, the synchronization control method includes: (A) initializing the controllers; (B) each controller selecting a synchronous rotation or an asynchronous rotation, When selecting non-synchronous rotation, proceed to step (C), select synchronous rotation, enter step (D); (C) each controller generates a non-synchronous rotation command, enter step (E); (D) each controller selects Synchronizing the target and generating a synchronous rotation command, proceeding to step (F); (E) the driver corresponding to each controller controls the corresponding motor to rotate asynchronously with the other motor according to the asynchronous rotation command, and then the corresponding motor drives the corresponding The rotating shaft rotates asynchronously with the other rotating shafts; and (F) the corresponding driver of each controller controls the corresponding motor to rotate synchronously with the other motors according to the synchronous rotating command, and then the corresponding motor Moving the rotary shaft corresponding to the rotation shaft of the other rotates synchronously. According to the synchronous control method of claim 7 of the patent application, after step (E), further comprising: (G) changing to synchronous rotation, if yes, proceeding to step (D), and if not, proceeding to step (E). According to the synchronous control method of claim 7 of the patent application, after step (F), further comprising: (H) Is it changed to asynchronous rotation, if yes, go to step (C), and if no, go to step (F). According to the synchronous control method of claim 7, wherein each controller generates at least one virtual mark, the virtual mark is located at a specific position in a rotation range of the corresponding rotation axis, and each controller rotates according to one of the corresponding rotation axes. The angle rotation signal, the corresponding virtual mark, one of the other rotation axis rotation angle signals, and the virtual mark generated by the other controllers generate the synchronous rotation command. According to the synchronous control system of claim 10, wherein when each of the rotation axes and the rotation angle signal is 1:1, each controller rotates one rotation of the rotation angle signal to correspond to the position of each rotation axis as the virtual mark is generated. Reference. According to the synchronous control method of claim 10, wherein when each of the rotation axes and the rotation angle signal is not 1:1, each controller rotates one rotation of each rotation axis as a reference for generating the virtual mark. According to the synchronous control method of claim 10, wherein each of the controllers generates a plurality of virtual tokens, the virtual tokens are evenly distributed in the rotation range of the corresponding rotation axis.