Servo amplifier system

Provided is a servo amplifier system performing a multi-axis control for multiple axes, in which the multiple axes includes a first axis group which an axis to be locked, at the time of power supply abnormality in the multi-axis control, belongs to, and a second axis group which an axis to be subjected to servo-off belongs to, the servo-off being made before the axis belonging to the first axis group is locked at the time of the power supply abnormality.

TECHNICAL FIELD

The present disclosure relates to a servo amplifier system performing a multi-axis control.

BACKGROUND ART

Conventionally, various techniques have been proposed for a servo amplifier system performing a multi-axis control. For example, the technique disclosed in Patent Literature 1 is a control device for controlling a mechanical apparatus including a gravity axis, a motor that drives the gravity axis, and a brake device that brakes the gravity axis, the control device including a servo amplifier that is connected to the motor of the mechanical apparatus and controls the motor, a brake circuit that is connected to the brake device of the mechanical apparatus and controls the brake device, a main control section that is connected to the servo amplifier and connected to the brake circuit, supplies a drive signal and a power shutoff signal for controlling the motor to the servo amplifier by the servo amplifier, and supplies a brake effective signal for controlling the brake device to the brake circuit by the brake circuit, a control power supply that supplies a power shutoff command signal, for supplying the power shutoff signal to the servo amplifier, to the main control section by the main control section, and directly supplies the brake effective signal to the brake circuit, and a delay circuit that is interposed between the control power supply and the main control section to delay a timing at which the power shutoff command signal is supplied to the main control section, in which the brake circuit immediately controls the brake device based on the brake effective signal from the control power supply to brake the gravity axis by the brake device.

PATENT LITERATURE

BRIEF SUMMARY

Technical Problem

According to the disclosure of Patent Literature 1, a control device having such a characteristic can prevent the gravity axis from spontaneously falling when a power supply is turned off, but a more preferable measure has been demanded.

The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to provide a servo amplifier system in which measures are preferably taken at the time of power supply abnormality in a multi-axis control.

Solution to Problem

The present specification discloses a servo amplifier system performing a multi-axis control for multiple axes, in which the multiple axes includes a first axis group which an axis to be locked, at the time of power supply abnormality in the multi-axis control, belongs to, and a second axis group which an axis to be subjected to servo-off belongs to, the servo-off being made before the axis belonging to the first axis group is locked at the time of the power supply abnormality.

Advantageous Effects

According to the present disclosure, the servo amplifier system is preferably provided with the measures at the time of the power supply abnormality in a multi-axis control.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment embodying the present disclosure will be described with reference to the accompanying drawings. As shown inFIG.1, servo amplifier system1of the present embodiment includes component mounter10.FIG.1shows two component mounters10arranged in parallel on a common base11. Component mounter10is, for example, is a device which is connected to other devices such as a solder printing machine, a board inspection machine, and a reflow machine to constitute a production line, thereby producing a circuit board on which multiple electronic components are mounted. Since two component mounters10have the same configuration, one of them will be mainly described. In component mounter10, various devices such as board conveyance device13, component supply device15, and head driving mechanism17are attached on common base11. In the following description, as shown inFIG.1, a direction in which component mounter10are arranged in parallel is referred to as an X-axis direction, a direction parallel to a board plane of a circuit board to be conveyed and perpendicular to the X-axis direction is referred to as a Y-axis direction, and a direction perpendicular to both the X-axis direction and the Y-axis direction is referred to as the Z-axis direction.

Board conveyance device13is a so-called double conveyor type device in which first conveyance device21and second conveyance device23are arranged in parallel in the Y-axis direction. Each of first conveyance device21and second conveyance device23has a pair of conveyor belts (not shown) disposed along the X-axis direction. Each of first conveyance device21and second conveyance device23circulates a pair of conveyor belts to convey a circuit board supported on the conveyor belts in the X-axis direction. In addition, each of first conveyance device21and second conveyance device23holds and fixes a circuit board, conveyed to a stop position where a mounting work of electronic components is performed, by a stopper (not shown) provided at the upper portion of the circuit board and a clamper (not shown) provided at the lower portion of the circuit board, in the Z-axis direction. For example, each of first conveyance device21and second conveyance device23conveys a circuit board conveyed from an upstream device such as a solder printing machine in the X-axis direction, and clamps the circuit board at the stop position. When the mounting work is ended, first conveyance device21and second conveyance device23convey the circuit board in the X-axis direction and convey the circuit board out to a device at a later stage.

component supply device15is a feeder type device and is provided at a front end portion (lower left side inFIG.1) of component mounter10in the Y-axis direction. In component supply device15, multiple feeders25arranged in parallel in the X-axis direction are provided on common base11. Each feeder25is configured to be detachable from common base11, and supplies electronic components from tape feeder27to a supply position. Tape feeder27is a medium for supplying the electronic components and is wound with a carrier tape which holds multiple electronic components at constant intervals. In feeder25, a distal end of the carrier tape is pulled out to the supply position, and different types of electronic components are supplied for each of carrier tapes. The supply position of each feeder25is arranged in parallel along the X-axis direction. Therefore, the supply position is different in the X-axis direction for different types of electronic components.

In addition, head driving mechanism17is an XY-robot type moving device. Head driving mechanism17includes X-axis servo motor41(refer toFIG.2) that slides slider31in the X-axis direction, and Y-axis servo motor43(refer toFIG.2) that slides in the Y-axis direction. Mounting head33is attached to slider31. Mounting head33moves to a random position on each frame portion35of component mounter10placed on common base11by driving two servo motors41and43. X-axis servo motor41and Y-axis servo motor43can use, for example, a linear motor mechanism or a ball screw feed mechanism as a moving mechanism. A movement distance of mounting head33is longer in the Y-axis direction than in the X-axis direction. Due to such a movement distance or the like, the power consumption of Y-axis servo motor43is larger than the power consumption of X-axis servo motor41.

Nozzle holder37is provided below mounting head33. Nozzle holder37holds multiple mounting nozzles downward. Each of the mounting nozzles communicates with a negative pressure air passage and a positive pressure air passage via a positive and negative pressure supply device (not shown), picks up and holds an electronic component by the negative pressure, and separates the held electronic component by being supplied with a slight positive pressure. Mounting head33has R-axis servo motor45(refer toFIG.2) that rotationally drives nozzle holder37around the Z-axis. In addition, mounting head33has Z-axis servo motor47(refer toFIG.2) that individually extends the selected mounting nozzle downward in the Z-axis direction and retracts upward in the Z-axis direction. In addition, mounting head33has Q-axis servo motor49(refer toFIG.2) that rotationally drives the selected mounting nozzle around the Z-axis individually.

Board conveyance device13, component supply device15, head driving mechanism17, and mounting head33described above are connected to control device51(refer toFIG.2) by a communication cable. Control device51acquires various information from each of devices13to17, and executes arithmetic, a determination, and the like based on the acquired information. In addition, control device51appropriately controls the operations of devices13to17based on an arithmetic result and a determination result. In component mounter10, the mounting work of electronic components is controlled by control device51. Further, in component mounter10, operation device29is provided at a front end portion of an upper cover. The operator can confirm the information output to operation device29by control device51, and perform necessary operations and settings on operation device29.

Component mounter10having the above-described configuration repeatedly executes the mounting work of mounting the electronic component at the supply position to the mounting position of the circuit board by driving head driving mechanism17and mounting head33based on the control of control device51. Specifically, first, head driving mechanism17moves mounting head33to a position above the supply position of feeder25to which an electronic component to be mounted is supplied. Mounting head33picks up the electronic component at the supply position by the mounting nozzle. Next, head driving mechanism17moves mounting head33to a position above the circuit board which is positioned at the stop position by board conveyance device13. Then, in mounting head33, Z-axis servo motor47is driven to extend the mounting nozzle downward in the Z-axis direction. At this time, as shown inFIG.3, in nozzle holder37of mounting head33, lifting and lowering shaft71lowers in a state in which electronic component EP is picked up by mounting nozzle73provided at the lower end thereof. Further, in mounting head33, when electronic component EP abuts the mounting position of circuit board CB on board conveyance device13, the negative pressure of mounting nozzle73is released, so that electronic component EP is separated and mounted on circuit board CB.

As shown inFIG.2, component mounter10includes servo amplifier53in addition to the above-described configuration, and further includes main control section55and servo controller57in control device51. Main control section55is configured to be mainly a computer, and includes an arithmetic circuit such as a CPU, a memory device such as a RAM and a ROM, and controls entire component mounter10.

Servo controller57is connected to main control section55in control device51and is connected to servo amplifier53by a communication cable. Servo controller57constitutes a servo mechanism by servo motors41and43of head driving mechanism17and servo motors45to49of mounting head33described above, in addition to main control section55and servo amplifier53. As a result, the mounting work of the electronic component EP described above is performed by performing the multi-axis control.

Servo amplifier53includes converter59, voltage detecting section61, and servo control section63. Converter59rectifies an alternating current of connected power supply P, smooths the rectified alternating current with a capacitor, and converts the rectified alternating current into a direct current. Power supply P is, for example, a commercial power supply, and is also connected to control device51to supply power to the above-described multi-axis control.

Voltage detecting section61is connected to converter59and servo control section63in servo amplifier53. Voltage detecting section61transmits a warning signal to servo control section63when the voltage of converter59decreases and becomes smaller than a reference value (for example, a value below the commercial power supply voltage). When servo control section63receives the warning signal, it notifies main control section55of the fact via servo controller57.

Servo control section63is connected to each of servo motors41and43of head driving mechanism17and each of servo motors45to49of mounting head33by a communication cable. Servo control section63sets each of servo motors41and43of head driving mechanism17and each of servo motors45to49of mounting head33in a servo-on state or a servo-off state in accordance with a command from servo controller57. Accordingly, servo amplifier53including above servo control section63is of a multi-axial integral type.

Mounting head33further includes Z-axis locking device39. Z-axis locking device39is configured to automatically lock lifting and lowering shaft71by shutting off the power supply so as to disable the up-down movement in the Z-axis direction. In addition, Z-axis locking device39is connected to main control section55by a communication cable. As a result, for example, by transmitting a low-level signal to Z-axis locking device39, main control section55can automatically lock lifting and lowering shaft71so as to disable the up-down movement in the Z-axis direction in the same manner as when the power supply is shut off. Since above Z-axis locking device39is configured by a well-known technique, a detailed description thereof will be omitted.

In servo amplifier system1of the present embodiment, lifting and lowering shaft71is prevented from falling by its own weight at the time of power supply abnormality in the multi-axis control as described above. Accordingly, each processing shown in the flowchart inFIG.4is executed by, for example, a servo middleware operating in main control section55.

Examples of the power supply abnormality include a case where power supply P fails to power. In such a case, main control section55continues the operation of the servo middleware by, for example, electric power charged in the capacitor. In addition, the operation of servo amplifier53is performed by the electric power charged in the capacitor in converter59.

First, in step S10, main control section55determines whether a notification indicating that servo control section63has received the warning signal of voltage detecting section61is received from servo controller57. This determination is performed again in a case where main control section55has not received the notification described above (S10: NO).

On the other hand, in a case where main control section55receives the notification described above (S10: YES), the first servo-off processing is performed in step S12. In this processing, main control section55sets each of servo motors41and43of head driving mechanism17in the servo-off state via servo controller57and servo control section63. At this time, servo motors41and43of head driving mechanism17are placed in the servo-off state in the descending order of power consumption. Accordingly, Y-axis servo motor43is placed in the servo-off state, and then X-axis servo motor41is placed in the servo-off state. As a result, the servo-on state of Z-axis servo motor47is maintained by an electric power obtained by adding a regenerative energy returned to the capacitor in converter59until each of servo motors41and43stops.

Subsequently, in step S14, locking processing is performed. In this processing, main control section55locks lifting and lowering shaft71via Z-axis locking device39.

Further, in step S16, the second servo-off processing is performed. In this processing, after a lapse of time required to complete the locking of Z-axis locking device39, main control section55sets each of servo motors45,47, and49of mounting head33in the servo-off state via servo controller57and servo control section63.

As described in detail above, servo amplifier system1of the present embodiment is preferably provided with measures at the time of the power supply abnormality in the multi-axis control.

In the present embodiment, component mounter10is an example of a mounter. An axis group including X-axis servo motor41and Y-axis servo motor43is an example of the second axis group. An axis group including Z-axis servo motor47is an example of the first axis group. Voltage detecting section61is an example of a detecting section.

The present disclosure is not limited to the above-described embodiment, and various modifications can be made within the scope not departing from the concept of the present disclosure. For example, in the first servo-off processing (S12) or the second servo-off processing (S16), servo control section63may place each of servo motors41to49in the servo-off state instead of main control section55.

In addition, in a configuration in which a signal is input and output between servo amplifier53and Z-axis locking device39, at the timing when servo control section63receives the warning signal, the signal output from servo amplifier53and input to Z-axis locking device39may be treated as a trigger, whereby locking of lifting and lowering shaft71in locking processing (S14) may be started.

In addition, by providing voltage detecting section61between power supply P and servo amplifier53, the warning signal of voltage detecting section61may be input to servo controller57.

Further, servo amplifier53may be configured by a combination of a multi-axial integral type and a one-axial type, or may be configured by five one-axial types. However, in such a case, voltage detecting section61is provided in a servo amplifier for controlling Y-axis servo motor43or X-axis servo motor41, or is provided between a servo amplifier for controlling Y-axis servo motor43or X-axis servo motor41and power supply P.

In addition, the present disclosure may be embodied by a machine tool or the like.

REFERENCE SIGNS LIST