JP6806780B2 - Linear drive unit servo off stop position control system - Google Patents

Description

The present invention relates to a servo-off stop position control system for a linear drive device that controls a stop position when a linear drive device linearly drives a drive object with a linear servomotor.

Some linear drive devices that linearly drive a drive object use a linear servomotor as a drive source in order to control the stop position of the drive object with high accuracy (see Patent Document 1). While the device is in operation, the linear servomotor is maintained in the servo-on state even when the mover is stopped, and the stop position of the mover is held. However, when the operation ends, the servo is turned off and the linear servomotor can move. The holding of the child is released, and the movable child can move freely.

Japanese Unexamined Patent Publication No. 11-126996

By the way, during the operation of the device, the linear servomotor may be servo-off due to an error or replacement of a driving object. As described above, when the linear servomotor is servo-off, the mover (drive target) becomes freely movable. Therefore, when an external force acts on the mover (drive target), the mover (drive target) is moved. The object) shifts from the original stop position. External forces acting on the mover (drive object) during servo-off include, for example, tension of the power line and signal line cables connected to the mover (drive object), magnetic force of the stator magnet, gravity, and the like. .. If the mover (driving object) shifts while the servo is off, the operator may mistake it for an abnormal operation (fault), and the displaced driving object may interfere with other objects in the device. is there. Moreover, if the stop position of the mover (drive object) deviates from the original stop position during servo-off, it takes time to return the mover (drive object) to the original stop position at the time of restart, and the restart is performed. There is also the drawback of being late.

Therefore, an object to be solved by the present invention is to provide a stop position control system at the time of servo-off of a linear drive device that can prevent the mover (driving object) from shifting and moving as much as possible while the linear servo motor is servo-off. ..

In order to solve the above problems, the present invention provides a servo-off of a linear drive device provided with a control means for controlling a stop position when the linear servo motor is servo-off in a linear drive device that linearly drives a drive object with a linear servo motor. The time-stop position control system includes a storage means for storing a stable stop position in which the drive object stably maintains a stopped state during servo-off of the linear servomotor in the movement range of the drive object. When the linear servomotor is servo-off, the control means selects the stable stop position closest to the current position from the stable stop positions stored in the storage means, and continues until the closest stable stop position is reached. The first feature is that the stop position at the time of servo-off is controlled to coincide with the nearest stable stop position by continuing the driving of the linear servomotor and then servo-off . Further, the control means is described as described above. The normal control mode for controlling the stop position when the servo of the linear servomotor is off and the stable stop position measurement mode for measuring the stable stop position can be switched. In the stable stop position measurement mode, the driving object is driven. The linear servomotor is intermittently driven by alternately switching between servo-on and servo-off so that the drive object moves by a predetermined pitch in the movement range, and the drive object is stably maintained in a stopped state during servo-off. The second feature is to measure the stable stop position to be performed and store the measured value in the storage means. In this way, when the linear servo motor is servo-off, if the servo is turned off after reaching the stable stop position closest to the current position, the stop position at the time of servo-off is always the stable stop position, and the mover during servo-off. It is possible to prevent the (driving object) from shifting as much as possible, and to solve the above-mentioned problems.

The servo-off stop position control system of the linear drive device of the present invention can be applied to various devices equipped with the linear drive device. For example, when applied to a component mounting machine, the mounting head is used as a driving object, and the mounting head is used as a driving object. The linear drive device may be used as the mounting head moving device for moving the mounting head in the X-axis direction and / or the Y-axis direction.

As a second feature of the present invention, the control means can switch between a normal control mode for controlling the stop position when the servo of the linear servomotor is off and a stable stop position measurement mode for measuring the stable stop position. In the stable stop position measurement mode, the linear servomotor is intermittently driven by alternately switching between servo-on and servo-off so that the drive object moves in a predetermined pitch in the movement range of the drive object. by measuring the stable stop position to maintain a stopped state by the driving object stably during servo OFF, and so as to store the measured value in the storage means. In this case, only the manufacturer or the seller of the device may be configured to switch to the stable stop position measurement mode, and the manufacturer or the seller may measure the stable stop position, or the user may also measure the stable stop position. It may be configured so that the mode can be switched so that the user can also measure the stable stop position. If the user can measure the stable stop position, it is possible to cope with the time-dependent deviation of the stable stop position due to changes in the device over time.

Further, in the stable stop position measurement mode, the control means is set to a predetermined time in which the servo-off time is expected to be the time required for the driven object to stop stably, and the predetermined time is set for each servo-off. When the elapsed time has passed, it may be considered that the driven object has stopped stably, and the stable stop position may be measured.

Alternatively, in the stable stop position measurement mode, the control means continues the servo-off until the drive target maintains the stopped state for a predetermined time each time the servo is turned off, and the drive target maintains the stopped state for a predetermined time. After measuring the stable stop position, the operation of switching to the servo on, moving the driving object by the predetermined pitch, and turning off the servo may be repeated.

The present invention is not limited to the configuration for measuring the stable stop position, and the stable stop position may be calculated in advance based on the magnetic pole pitch and the origin position of the linear servomotor and stored in the storage means. For example, among the external forces acting on the mover (drive target) during servo off, the tension of the power line and signal line cables connected to the mover (drive target) is relatively small, and the magnetic force of the stator magnet When the influence is overwhelmingly large, the stable stop position can be calculated accurately based on the magnetic force pitch and the origin position of the linear servomotor.

FIG. 1 is a perspective view showing a configuration of a main part of a component mounting machine according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a control system of a component mounting machine. FIG. 3 is a flowchart showing the processing flow of the stop position control program when the servo is off.

Hereinafter, an embodiment in which the embodiment for carrying out the present invention is applied to a component mounting machine will be described.
First, the configuration of the component mounting machine 11 will be described with reference to FIG.
A component supply device 12 for supplying components is detachably set in the component mounting machine 11. The component supply device 12 set in the component mounting machine 11 may be any of a tray feeder, a tape feeder, a bulk feeder, a stick feeder, and the like, and of course, a plurality of types of feeders may be mixedly mounted. The component mounting machine 11 includes a conveyor 13 that conveys a circuit board (not shown), a mounting head 14 (driving object) that mounts components supplied by the component supply device 12 on the circuit board, and the mounting head 14. A mounting head moving device 15 for moving the mounting head in the X-axis direction (transportation direction of the circuit board) and the Y-axis direction perpendicular to the X-axis direction, a nozzle station 16 on which a replacement suction nozzle (not shown) is mounted, and the like are provided. Has been done.

A suction nozzle (not shown) for sucking the parts supplied by the parts supply device 12 is interchangeably held in the mounting head 14. The component mounting machine 11 is provided with a camera 17 for capturing a component that images a component held by a suction nozzle from below, and the mounting head 14 is provided with a camera 18 for capturing a mark that captures a reference position mark of a circuit board. Is provided.

The mounting head 14 is provided with a Z-axis slide 24 driven by a Z-axis motor 22 in the Z-axis direction (vertical direction), and a suction nozzle is provided by lowering / raising the Z-axis slide 24 during component suction operation or component mounting operation. Is designed to be lowered / raised.

The mounting head moving device 15 includes an X-axis slide device 26 whose drive source is an X-axis motor 25 made of a servomotor or the like, and a Y-axis slide device 28 (linear drive device) whose drive source is a Y-axis linear servomotor 27. It is composed of. The X-axis slide device 26 rotates the X-axis ball screw 29 with the X-axis motor 25 to move the X-axis slide (not shown) to which the mounting head 14 is attached in the X-axis direction along the X-axis guide 30. Let me. The X-axis guide 30 is supported by the Y-axis guide 31 of the Y-axis slide device 28 so as to be slidable in the Y-axis direction, and is X-axis slide 32 attached to the mover 33 of the Y-axis linear servomotor 27. The shaft guide 30 is connected. As a result, the X-axis slide device 26 is moved in the Y-axis direction along the Y-axis guide 31 by the Y-axis linear servomotor 27. The stator 34 of the Y-axis linear servomotor 27 is provided so that two rows of magnets facing each other with the mover 33 interposed therebetween extend parallel to the Y-axis direction.

The control device 41 (control means) of the component mounting machine 11 is mainly composed of a computer, and includes an input device 42 such as a keyboard, a mouse, and a touch panel, a display device 43 such as an LCD, EL, and CRT, and a component mounting machine 11. Various control programs for controlling the operation of each function, a storage device 44 (storage means) for storing various data such as a map of stable stop positions described later, and the like are connected. The storage device 44 is composed of a rewritable non-volatile storage medium such as a hard disk device.

The control device 41 of the component mounting machine 11 controls the operations of the X-axis motor 25, the Y-axis linear servomotor 27, the Z-axis motor 22, and the like of the mounting head moving device 15 during operation (during production) to control the mounting head. 14 is moved between the component suction position on the component supply device 12 side and the component mounting position on the circuit board to execute the component suction operation and the component mounting operation.

By the way, while the component mounting machine 11 is in operation, the Y-axis linear servomotor 27 is maintained in the servo-on state even when the mover 33 (mounting head 14) is stopped, and the stop position of the mover 33 is held. However, even during the operation of the component mounting machine 11, the Y-axis linear servomotor 27 may be servo-off due to an error or replacement of the mounting head 14. When the Y-axis linear servomotor 27 is servo-off, the mover 33 (mounting head 14) is in a state where it can move freely. Therefore, when an external force acts on the mover 33 (mounting head 14), the mover 33 (mounting) The head 14) shifts from the original stop position. As the external force acting on the mover 33 (mounting head 14) during servo-off, for example, the tension of the power line or signal line cable connected to the mover 33 and the mount head 14, the magnetic force of the magnet of the stator 34, and the like. is there. If the mover 33 (mounting head 14) shifts while the servo is off, the operator may mistake it for an abnormal operation (fault), and the displaced mounting head 14 interferes with other objects in the component mounting machine 11. There is also the possibility of doing. Moreover, if the stop position of the mover 33 (mounting head 14) deviates from the original stop position during servo-off, it takes time to return the mover 33 (mounting head 14) to the original stop position at the time of restart, and the operation is repeated. It also has the disadvantage of delaying operation.

Therefore, in this embodiment, the map of the stable stop position in which the mounting head 14 stably maintains the stopped state while the servo of the Y-axis linear servomotor 27 is off is stored in the storage device 44, and the control device 41 of the component mounting machine 11 is stored. Is currently executed from the map of the stable stop position stored in the storage device 44 when the Y-axis linear servomotor 27 is servo-off by repeatedly executing the servo-off stop position control program of FIG. 3 during operation. By selecting the stable stop position closest to the position and continuing to drive the Y-axis linear servomotor 27 until the closest stable stop position is reached, the servo is turned off, so that the stop position at the time of servo off is the closest stable stop position. Control to match.

Further, in this embodiment, in order to create a map of the stable stop position, the control mode of the component mounting machine 11 is set to the stop position when the Y-axis linear servomotor 27 is servo-off according to the servo-off stop position control program of FIG. It is possible to switch between the normal control mode for controlling and the stable stop position measurement mode for measuring the stable stop position. In the stable stop position measurement mode, the mounting head 14 sets the Y-axis direction movement range of the mounting head 14. The Y-axis linear servomotor 27 is intermittently driven by alternately switching the servo-on and servo-off of the Y-axis linear servomotor 27 so as to move by a predetermined pitch, and the mounting head 14 is stably maintained in a stopped state during the servo-off. The stable stop position is measured, and the measured value is stored in the storage device 44. At this time, in the stable stop position measurement mode, the energization of the linear encoder (not shown) that detects the position of the mover 33 of the Y-axis linear servomotor 27 is maintained even during the servo off, and the output signal of this linear encoder is used. Based on this, the stable stop position is measured. The pitch for intermittently driving the Y-axis linear servomotor 27 is preferably smaller than the magnetic pole pitch of the stator 34, and more preferably 1 / N of the magnetic pole pitch of the stator 34 (where N is an integer of 2 or more). For example, it may be set to 1/2 to 1/3 of the magnetic pole pitch.

In this case, only the manufacturer or the distributor of the component mounting machine 11 may be configured to be able to switch to the stable stop position measurement mode, and the manufacturer or the distributor may measure the stable stop position, or the component mounting machine 11 may be measured. It may be configured so that the user who uses the above can switch to the stable stop position measurement mode so that the user can also measure the stable stop position. If the user can measure the stable stop position, it is possible to cope with the time-dependent deviation of the stable stop position due to the time-dependent change of the component mounting machine 11.

Further, in the stable stop position measurement mode, the servo-off time is set to a predetermined time that allows for the time required for the mounting head 14 to stop stably, and when the predetermined time elapses for each servo-off, the mounting head 14 May be considered to have stopped stably and the stable stop position may be measured.

Alternatively, in the stable stop position measurement mode, the servo off is continued until the mounting head 14 maintains the stopped state for a predetermined time each time the servo is turned off, and after the stable stop position is measured when the mounting head 14 maintains the stopped state for a predetermined time. , The operation of switching to the servo on, moving the mounting head 14 by a predetermined pitch, and turning off the servo may be repeated.

The present invention is not limited to the configuration for measuring the stable stop position, and the stable stop position is calculated in advance based on the magnetic pole pitch and the origin position of the stator 34 of the Y-axis linear servomotor 27 and stored in the storage device 44. You can do it. For example, among the external forces acting on the mover 33 and the mounting head 14 during the servo-off of the Y-axis linear servomotor 27, the tension of the power line and signal line cables connected to the mover 33 and the mounting head 14 is relatively small. When the influence of the magnetic force of the magnet of the stator 34 is overwhelmingly large, the stable stop position can be calculated accurately based on the magnetic pole pitch and the origin position of the Y-axis linear servomotor 27.

The stop position control of the Y-axis linear servomotor 27 of the present embodiment described above at the time of servo-off is executed by the control device 41 of the component mounting machine 11 as follows according to the servo-off stop position control program of FIG. The stop position control program at the time of servo-off in FIG. 3 is repeatedly executed at a predetermined cycle during the operation of the component mounting machine 11. When this program is started, first, in step 101, it is determined whether or not a servo-off request has occurred due to an error or replacement of the mounting head 14, and if no servo-off request has occurred, the subsequent processing is performed. Exit this program without fail.

After that, when the servo-off request is generated, the process proceeds from step 101 to step 102, the stable stop position closest to the current position is selected from the map of the stable stop position stored in the storage device 44, and the process proceeds to step 103 to move. The Y-axis linear servomotor 27 is continuously driven (servo-on is continued) until the child 33 (mounting head 14) reaches the nearest stable stop position.

Then, in the next step 104, when it is determined that the mover 33 (mounting head 14) has reached the nearest stable stop position, the process proceeds to step 105, and the drive of the Y-axis linear servomotor 27 is stopped. In the following step 106, the servo is turned off and the program ends.

In the present embodiment described above, when the Y-axis linear servomotor 27 is servo-off, the mover 33 (mounting head 14) reaches the stable stop position closest to the current position and then the servo is turned off. The stop position at the time is always the stable stop position, and it is possible to prevent the mover 33 (mounting head 14) from shifting and moving as much as possible while the servo is off. As a result, it is possible to prevent the mounting head 14 from shifting during servo-off, which the operator misunderstands as an abnormal operation (fault), and the mounting head 14 shifts during servo-off and interferes with other objects in the component mounting machine 11. It can also be prevented. Moreover, since the stop position of the mover 33 (mounting head 14) does not deviate from the original stop position during servo-off, the mover 33 (mounting head 14) is returned to the original stop position when restarting. There is also the advantage that it can be restarted early without having to do it.

In this embodiment, only the drive source (Y-axis motor) of the Y-axis slide device 28 of the mounting head moving device 15 is configured by a linear servomotor, but the X-axis motor 25 of the X-axis slide device 26 is also linear. It may be configured by a servomotor, and the Z-axis motor 22 that moves the suction nozzle up and down may also be configured by a linear servomotor.

Further, the scope of application of the present invention is not limited to the component mounting machine 11, and may be applied to devices (solder printing machines, etc.) in each process arranged on the component mounting line that produces the component mounting board. It may be applied to equipment in each process of a production line other than the component mounting line, and the point is that any equipment equipped with a linear drive that linearly drives the object to be driven by a linear servomotor is used regardless of the application. , The present invention can be applied and carried out.

In addition, the present invention is not limited to the present embodiment, and can be variously modified without departing from the gist, for example, the configuration of the linear drive device (mounting head moving device 15) may be appropriately changed. Needless to say.

11 ... Parts mounting machine, 12 ... Parts supply device, 14 ... Mounting head (drive object), 15 ... Mounting head moving device, 26 ... X-axis slide device, 27 ... Y-axis linear servo motor, 28 ... Y-axis slide device (Linear drive device), 33 ... Movable element, 34 ... Stator, 41 ... Control device (control means), 44 ... Storage device (storage means)

Claims (5)

In a linear drive device that linearly drives a drive object with a linear servomotor, in a servooff stop position control system of the linear drive device provided with a control means for controlling the stop position of the linear servomotor when the servo is off.
A storage means for storing a stable stop position in which the drive object stably maintains a stopped state during servo-off of the linear servomotor in the movement range of the drive object is provided.
When the linear servomotor is servo-off, the control means selects a stable stop position closest to the current position from the stable stop positions stored in the storage means and reaches the nearest stable stop position. A servo-off stop position control system for a linear drive device that controls the stop position during servo-off so that it coincides with the nearest stable stop position by continuing to drive the linear servomotor and then servo-off .
The control means is configured to be able to switch between a normal control mode for controlling the stop position when the servo of the linear servomotor is off and a stable stop position measurement mode for measuring the stable stop position. In the stable stop position measurement mode. , The linear servomotor is intermittently driven by alternately switching between servo on and servo off so that the drive object moves by a predetermined pitch in the movement range of the drive object, and the drive object is stable during servo off. A servo-off stop position control system for a linear drive device, characterized in that a stable stop position for maintaining a stopped state is measured and the measured value is stored in the storage means . The drive object is a mounting head of a component mounting machine.
The servo-off stop position control system for a linear drive device according to claim 1, wherein the linear drive device is a mounting head moving device that moves the mounting head in the X-axis direction and / or the Y-axis direction. In the stable stop position measurement mode, the control means is set to a predetermined time in which the servo-off time is expected to be the time required for the driven object to stop stably, and the predetermined time elapses for each servo-off. The stop position control system at the time of servo-off of the linear drive device according to claim 1 or 2 , wherein the stable stop position is measured by regarding that the drive object has stopped stably at a time point. In the stable stop position measurement mode, the control means continues the servo-off until the driven object maintains the stopped state for a predetermined time each time the servo is turned off, and when the driven object maintains the stopped state for a predetermined time, the stable state is maintained. The stop position control at the time of servo-off of the linear drive device according to claim 1 or 2 , wherein after measuring the stop position, the operation of switching to servo-on, moving the drive object by the predetermined pitch, and servo-off is repeated. system. The linear according to claim 1 or 2, wherein the data of the stable stop position stored in the storage means is data calculated in advance based on the magnetic pole pitch and the origin position of the linear servomotor. Stop position control system when the servo of the drive unit is off.

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