JP5291889B2 - Automatic machine automatic operation control method - Google Patents

Description

  The present invention relates to an automatic operation control method for an automatic machine using a servomotor driven by a program.

  Conventionally, the overload detection method for motors described in Patent Document 1 is known. In this motor overload detection method, a motor current (torque) is detected by a current detector attached to a motor power line, and an effective current value (effective torque value) obtained from the detected motor current (torque) and a threshold value are detected. And the effective current value (effective torque value) exceeds the threshold value, it is determined that the motor is in an overload state. If this motor overload detection method is used in the automatic operation control method of an automatic machine, the overload state of the servomotor can be determined and the servomotor can be protected.

  Here, for example, in the automatic operation control method of the electronic component mounting apparatus, it is necessary to drive the servo motor at high acceleration and high speed in order to increase productivity, and the largest torque is required in the operation cycle. In the portion, it may be necessary to drive the servo motor with a torque higher than the rated torque. In this case, it is possible to instantaneously generate torque several times the rated torque. However, as shown in FIG. 7, within a certain time (ts) of the operation cycle, if the servo motor is not driven within the range of the effective torque equation shown in the following equation 1, the servo motor is overloaded and the automatic machine Will have to stop. Note that F is a rated torque, and sqrt {} is a function for obtaining a square root.

(Equation 1)

F ≧ sqrt {(T1 ² × t1 + T2 ² × t2 +... + Tn ² × tn) / ts}

Therefore, in general, in the automatic operation control method of the electronic component mounting apparatus, programming is performed so as to satisfy the expression of the effective torque of the above formula 1. At this time, it is conceivable to monitor the overload state of the servo motor by using the motor overload detection method in combination.
JP 2004-242419 A (page 5, page 6, FIG. 1)

  However, in the above-described conventional automatic operation control method for an electronic component mounting apparatus, an operation cycle in which acceleration / deceleration of the servo motor is frequently repeated is assumed so that the operation cycle can be continuously operated, that is, the operation cycle is It was programmed so that the servo motor overload was not detected even if it was continuously operated. However, the actual automatic operation of the electronic component mounting apparatus includes many operation cycles that do not frequently repeat acceleration and deceleration of the servo motor. For this reason, in the conventional automatic operation control method for electronic component mounting devices, programming was performed to suppress acceleration / deceleration in accordance with an operation cycle in which acceleration / deceleration of the servo motor is frequently repeated, resulting in longer tact time and productivity. There was a risk of decline. In addition, when an overload state of the servo motor is detected by the motor overload detection method, the electronic component mounting apparatus must be stopped, which may reduce productivity.

  The present invention has been made in view of the above-described conventional problems, and provides an automatic operation control method for an automatic machine capable of shortening tact time and improving productivity.

In order to solve the above problem, the automatic operation control method for an automatic machine according to claim 1 is characterized in that in the automatic operation control method for an automatic machine using a servo motor driven by a program, the automatic operation control method is performed during one cycle. comparing the effective torque calculation step of calculating the effective torque of the servo motor, and the effective torque calculated in the effective torque calculation step with a threshold value based on the rated torque of the servo motor, the effective torque in the cycle When the effective torque is equal to or greater than the threshold value, the speed and acceleration of the servo motor are not decreased during the one cycle, and the next one cycle. And a load factor reduction step of reducing one or both of the speed and acceleration of the servo motor.

The automatic operation control method for an automatic machine according to claim 2 is characterized in that, in claim 1, the effective torque calculating step is repeatedly executed until the next one cycle is completed, and the comparing step is If the effective torque is smaller than the threshold value in the next one cycle, the fact that the effective torque has become smaller than the threshold value is stored. The acceleration is set to a preprogrammed value.

According to a third aspect of the present invention, there is provided an automatic operation control method for an automatic machine according to the first or second aspect, wherein, in the effective torque calculating step, the servo based on current position data of the servo motor or position command data from the program. It is to calculate the effective torque of the motor.

The automatic operation control method for an automatic machine according to claim 4 is characterized in that, in any one of claims 1 to 3 , the automatic machine is an electronic component mounting apparatus, and the electronic component mounting head is an electronic component in one cycle. This is a series of processes in which components are sucked from a feeder and mounted on a substrate .

In the automatic operation control method for an automatic machine according to claim 1 , when the effective torque is greater than or equal to the threshold value in one cycle , the load factor lowering step decreases one or both of the speed and acceleration of the servo motor in the next cycle. Therefore, the servo motor can be prevented from being overloaded, and the automatic machine can be prevented from stopping. Also, the automatic operation control method of the automatic machine, in accordance with the actual operation cycle can be lowered one or both of the velocity and acceleration of the servo motor, only if the effective torque is equal to or larger than the threshold in one cycle following In one cycle, one or both of the speed and acceleration of the servo motor are decreased. Therefore, it is not necessary to perform programming that suppresses acceleration / deceleration in accordance with an operation cycle in which acceleration / deceleration of the servo motor is frequently repeated. Therefore, according to this automatic machine automatic operation control method, the tact time can be shortened and the productivity can be improved.

In the automatic operation control method for an automatic machine according to claim 2, the effective torque becomes greater than or equal to a threshold value in one cycle, and one or both of the speed and acceleration of the servo motor are reduced in the next cycle, and in the next cycle, If the effective torque is smaller than the threshold value, the reduced speed and acceleration of the servo motor are set to pre-programmed values in each subsequent cycle, so that the tact time can be shortened and the productivity can be improved.

In the automatic operation control method for an automatic machine according to claim 3, in the effective torque calculation step, the current torque detector calculates the effective torque of the servomotor based on the current position data of the servomotor or the position command data from the program. It is not necessary to use a detector such as the above, and the production cost can be reduced.

In the automatic operation control method for an automatic machine according to claim 4 , the automatic machine is an electronic component mounting apparatus, and one cycle is a series of processes in which the electronic component mounting head sucks the electronic component from the feeder and mounts it on the substrate. Therefore, the above effect can be sufficiently obtained.

  DESCRIPTION OF EMBODIMENTS Embodiments embodying an automatic operation control method for an automatic machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a top view of an electronic component mounting apparatus 1 employing this automatic operation control method. The electronic component mounting apparatus 1 includes a component supply device 30, a substrate transfer device 20, and a component transfer device 10.

  The component supply device 30 is configured by arranging a plurality of feeders 31 on the base frame 2 in parallel. The feeder 31 holds a supply reel (not shown) around which a long and narrow tape in which electronic components are sealed at a predetermined pitch is wound. The tape is pulled out from the supply reel at a predetermined pitch, and the electronic components are released from the encapsulated state and sequentially fed into a component take-out portion (not shown).

  The board transfer device 20 has a pair of guide rails 21, 22 facing each other in parallel on the base frame 2 and arranged horizontally in parallel, and supports a printed board 25 guided by the guide rails 21, 22. A pair of conveyor belts (not shown) transported in the X-axis direction are arranged to face each other and arranged. Further, the substrate transport device 20 is provided with a clamp device (not shown) that pushes up and clamps the printed circuit board 25 transported to a predetermined position, and the printed circuit board 25 is positioned and fixed at the electronic component mounting position by the clamp device.

  The component transfer device 10 is of the XY robot type, is mounted on the base frame 2 and is disposed above the substrate transfer device 20 and the component supply device 30, and is driven by an X-axis servo motor 40a (see FIG. 3). An X-axis slider 11 that is moved in the X-axis direction is provided. The X-axis slider 11 holds a Y-axis slider 12 that is moved in the Y-axis direction by a Y-axis servomotor 40b (see FIG. 3). The Y-axis slider 12 is attached with an electronic component mounting head 13 that sucks and mounts the electronic component on the printed circuit board 25.

  FIG. 2 is a configuration diagram of the servo motor device 40 such as the X-axis servo motor 40a and the Y-axis servo motor 40b. The servo motor device 40 includes a servo motor 41, a rotary encoder 42, a servo amplifier 48, and the like. The rotation of the servo motor 41 is detected by the rotary encoder 42 and output as a pulse. This output pulse is input to the current counter 43 and used as current position data. The current position data of the current counter 43 is the current actual position of the object driven by the servo motor device 40 (for example, when the servo motor device 40 is an X-axis servo motor 40a, the electronic component mounting head 13 in the X direction). Current position data), and current position data is input to the deviation counter 45 and the control device 50. The control device controls the servo motor device 40. The moving position of an object driven by the servo motor device 40 (for example, when the servo motor device 40 is an X-axis servo motor 40a, the electronic component mounting head 13 A movement command having position command data corresponding to (position in the X direction) is output to the servo motor device 40. This position command data is input to the command counter 44 of the servo motor device 40 and further input to the deviation counter 45. The deviation counter 45 obtains a deviation between the position command data and the current position data, and this deviation is input to the servo amplifier 48 via the conversion function 46 and the D / A converter 47. A drive signal for driving the servo motor 41 is output by the servo amplifier 48. Thus, the current position data is fed back from the rotary encoder 42 via the current counter 43 to the position command data of the movement command, and the object is moved to a predetermined position by the servo motor 41.

  FIG. 3 is a schematic diagram of a control program of the electronic component mounting apparatus 1. A multitask system 51 is constructed in the control device 50. The multitask system 51 includes a multitask OS 52 and a plurality of tasks such as a task (1) 53, a task (2) 54, and a DWT (Duty Watcher Task) 55 controlled by the multitask OS 52. The plurality of tasks control the plurality of servo motor devices 40 such as the X-axis servo motor 40a and the Y-axis servo motor 40b. However, the DWT 55 monitors a plurality of servo motor devices 40 and instructs other tasks such as a task (1) 53 and a task (2) 54 to change the load factor of the servo motor 41.

  Next, the automatic operation control method of the electronic component mounting apparatus 1 will be described with reference to the flowchart of the DWT program shown in FIG. However, in this DWT program, it is assumed that one servo motor device 40 is monitored for convenience of explanation. When the execution of the DWT program is started, first, in step S10, an effective torque calculation subroutine shown in FIG. 5 is executed every 30 ms. Here, step S10 is an effective torque calculation step.

  In the effective torque calculation subroutine, the current position data of the electronic component mounting head 13 is acquired from the current counter 43 in step S20. In step S21, the difference value (numerical differentiation) of the current position data is taken twice to calculate the instantaneous torque. Here, the torque of an automatic machine that moves at a high speed like the electronic component mounting apparatus 1 is mainly an inertial force, and the acceleration and the torque can be proportional to each other. Further, in step S22, the effective torque is calculated by the above-described equation (1) (where ts is 60 sec). At this time, as shown in FIG. 6, assuming that the torque is constant for 30 ms, the effective torque is calculated by accumulating (numerical integration) them. After step S22 is executed, control is returned to the DWT program.

  In step S11, it is determined whether or not the calculated effective torque is greater than or equal to a threshold value. If the effective torque is greater than or equal to the threshold (YES), step S12 is executed. If the effective torque is smaller than the threshold value (NO), step S13 is executed. Here, step S11 is a comparison process. In the present embodiment, the threshold value is set to 95% of the rated torque, but the value can be changed according to the situation. In step S12, 1 is set to the over flag.

  In step S13, it is checked whether one cycle has been completed. When one cycle is completed (YES), step S14 is executed. If one cycle does not end (NO), the process returns to step S10. Here, one cycle is a period from when an electronic component is sucked from a feeder 31 to a suction nozzle (not shown) of the electronic component mounting head 13 until the electronic component is moved to a predetermined position on the printed circuit board 25 and mounted. A series of processes.

  In step S14, it is checked whether or not all cycles have been completed. When all the cycles are completed (YES), all the mounting of electronic components on one printed circuit board 25 is completed, and the DWT program is terminated. If all the cycles are not completed (NO), the mounting of the electronic components on one printed board 25 is not completed, and step S15 is executed.

  In step S15, it is checked whether or not the over flag is 1. When the over flag is 1 (YES), it indicates that the effective torque is equal to or greater than the threshold in the cycle ended immediately before, and step S17 is executed. When the over flag is not 1 (NO), it indicates that the effective torque was smaller than the threshold in the cycle ended immediately before, and step S16 is executed. In step S16, the normal load factor of the servo motor 41 is instructed to other tasks such as task (1) 53, task (2) 54, and the like. As a result, other tasks such as task (1) 53, task (2) 54, etc. do not lower the load factor of the servo motor 41, and the servo motor 41 is loaded at a pre-programmed load factor for the next one cycle. Can be driven.

  In step S17, the lowering of the load factor of the servo motor 41 is instructed to other tasks such as task (1) 53 and task (2) 54. Specifically, the servo motor 41 is stopped for a predetermined time (in this embodiment, 1 second) before starting the next cycle. In step S18, the over flag is cleared and the process returns to step S10. Here, step S17 is a load factor reduction process.

  In the automatic operation control method of the automatic machine according to the embodiment, in step S17, when the effective torque is equal to or greater than the threshold value, the load factor of the servo motor 41 is decreased, so that the servo motor 41 is prevented from being overloaded. It is possible to prevent the automatic machine from stopping. In this automatic operation control method for an automatic machine, the servo motor 41 can be accelerated / decelerated in accordance with the actual operation cycle, and the load factor of the servo motor 41 is reduced only when the effective torque exceeds the threshold. ing. Therefore, it is not necessary to perform programming that suppresses acceleration / deceleration in accordance with an operation cycle in which acceleration / deceleration of the servo motor 41 is frequently repeated. Therefore, according to the automatic operation control method of the automatic machine of the embodiment, the tact time can be shortened and the productivity can be improved.

  Further, in this automatic operation control method of the automatic machine, in step S17, the servo motor 41 is stopped for a predetermined time to reduce the load factor of the servo motor 41, so that the servo motor 41 is overloaded. Can be avoided. It should be noted that the load factor of the servo motor 41 can be reduced by reducing one or both of the speed and acceleration of the servo motor 41.

  Furthermore, in this automatic machine automatic operation control method, the effective torque of the servomotor 41 is calculated based on the current position data of the servomotor 41 in step S10, so there is no need to use a detector such as a current detector. Therefore, the production cost can be reduced. In step S10, the effective torque of the servo motor 41 can be calculated based on the position command data from the program. It is also possible to detect the current flowing in the coil of the servo motor 41 and calculate the effective torque of the servo motor 41 from this current. In addition, as a method for calculating the effective torque, hardware that calculates the effective torque from the torque extracted from the servo amplifier 48 can be employed. Furthermore, the load factor of the servo motor 41 can be reduced by detecting a warning that is a warning from the servo amplifier 48 without calculating the effective torque. In the present embodiment, the torque is calculated on the assumption that the torque and the acceleration are proportional to each other. However, the torque may be calculated in consideration of the frictional resistance.

  In the above, the automatic operation control method of the automatic machine according to the present invention has been described according to the embodiments. However, the present invention is not limited to these, and may be changed as appropriate unless it is contrary to the technical idea of the present invention. Needless to say, this is applicable. For example, the automatic operation control method can be applied to an automatic machine controlled by a loaded individual program, such as an NC machine tool or an automatic embroidery machine. In addition, the present invention can be applied to an automatic operation control method for an automatic machine using a linear motor by replacing torque with thrust.

The top view of the electronic component mounting apparatus according to the automatic operation control method of the automatic machine of the embodiment. The block diagram of a servomotor apparatus in connection with the automatic operation control method of the automatic machine of embodiment. The schematic diagram of the control program of the electronic component mounting apparatus according to the automatic operation control method of the automatic machine of the embodiment. The flowchart of a DWT program in connection with the automatic driving | operation control method of the automatic machine of embodiment. The flowchart of an effective torque calculation subroutine in connection with the automatic operation control method of the automatic machine of the embodiment. The figure which shows the calculation method of an effective torque in connection with the automatic operation control method of the automatic machine of embodiment. The figure which shows the torque in the driving | running cycle of an automatic machine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Automatic machine (electronic component mounting apparatus), 41 ... Servo motor, F ... Rated torque, S10 ... Effective torque calculation process, S11 ... Comparison process, S17 ... Load factor reduction process.

Claims (4)

In an automatic operation control method of an automatic machine using a servo motor driven by a program,
The effective torque calculation step of calculating the effective torque of the servo motor during one cycle,
It said effective torque calculated in the effective torque calculating step, a comparison step in which the comparison with the threshold value based on the rated torque of a servo motor, for storing said effective torque is equal to or greater than the threshold value in said one cycle,
When the effective torque is equal to or greater than the threshold value, a load for reducing one or both of the speed and acceleration of the servo motor in the next cycle without reducing the speed and acceleration of the servo motor for the one cycle. An automatic operation control method for an automatic machine comprising a rate reduction step. In claim 1,
The effective torque calculating step is repeatedly executed until the next one cycle is completed,
Said comparing step, if the effective torque in the next cycle is less than the threshold, storing said effective torque becomes smaller than the threshold value,
In the load factor lowering step, the reduced speed and acceleration of the servo motor are set to preprogrammed values in each successive cycle. In claim 1 or 2,
An automatic operation control method for an automatic machine, wherein, in the effective torque calculation step, an effective torque of the servo motor is calculated based on current position data of the servo motor or position command data from the program. In any one of Claims 1 thru | or 3,
The automatic machine is an electronic component mounting apparatus,
The one cycle is an automatic operation control method for an automatic machine, wherein the electronic component mounting head is a series of processes in which an electronic component is sucked from a feeder and mounted on a substrate.

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