JP3327298B2 - Method of generating speed command in tuning phase control of servo system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for generating a speed command in a servo system for driving a load having a plurality of drive shafts and requiring tuning phase control therebetween, and more particularly, to a method for generating a speed command at a constant tact time. And a method of generating a speed command that repeats the same pattern.

[0002]

2. Description of the Related Art Generally, when a metal, paper, film, plastic, rubber, or the like is machined by using a servo system by controlling a plurality of drive shafts with a plurality of machines, these drive shafts are controlled in speed and phase. It is necessary to drive in synchronization. Japanese Patent Laying-Open No. 4-99627 discloses a tuning phase control device of a servo system for performing this type of control, and detects an input speed command at regular time intervals using a CPU as a servo system controller. By multiplying the integrated value by a predetermined coefficient each time the integration is performed, a phase command serving as a common reference for each drive shaft is generated at a time and the reference phase command and a feedback from the pulse encoder of each drive shaft are generated. The deviation from the generated feedback position signal is calculated by integrating the pulse signals generated at the same time intervals, and the integrated value of the deviation is added to the reference speed signal and output as a rotation command for each drive shaft. Performs the tuning phase control of a plurality of drive shafts.

In the above-mentioned conventional tuning phase control method, a speed command is given to a servo system, and the speed and phase of each drive shaft are simultaneously made to reach a target value by using a high-speed calculation by a controller. FIG. 2 is a graph showing an example of the progress of the speed command curve during one tact time period in a case where such a control method is applied to the tuning phase control in which the same pattern shift is repeated at a constant tact time. Show. One tact time is 0.18 sec,
The value of the speed command Vref is 2.6681 m / s of the forward rotation speed.
forward during the deceleration time Td ₁ than ec is linear deceleration to speed 0m / sec in 0.036sec (curve 1). Then, the reverse rotation time of acceleration time and linear acceleration in the reverse direction Ta ₂ 0.02
In 9 sec, the reverse rotation speed reaches 1.2218 m / sec (curve 2), and continues this state for 0.050 sec (curve 3). Next, the reverse rotation deceleration time Td ₂ is 0.0
At 29 sec, the speed is linearly reduced again to the line with the speed of 0 m / sec (curve 4). Finally in the forward rotation during acceleration time Ta ₁ is 0.03
2.6681 m / sec in the forward direction of the original speed in 6 sec
(Curve 5). Each drive shaft has the speed command Vre
f, and the speed command V
Quickly follows the phase calculated from ref. Hereinafter, the above-mentioned speed command is repeatedly given.

[0004]

The method of giving a speed command in the above-described conventional tuning phase control requires that the speed and phase of the drive shaft at one tact time (point A) simultaneously reach target values. At this time, it is necessary that the speed and phase always fall within the target accuracy range. In this case, it is necessary to suppress the phase deviation of the drive shaft instantly,
This is disadvantageous in that when the required accuracy is severe, it is very difficult to perform control using ordinary hardware in terms of control. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of generating a speed command in tuning phase control, which can solve the above-mentioned drawbacks and achieve sufficient accuracy with ordinary hardware.

[0005]

According to the present invention, there is provided a method for generating a speed command in tuning phase control of a servo system, wherein the phase of a drive shaft is changed at the start of the tact time at the end of the tact time during the elapse of one tact time. Acceleration and deceleration of the speed command curve so that the drive shaft speed reaches the speed at the start of the tact time by at least the time necessary to return to the phase at the time before the end of the tact time. The speed is to be adjusted.

[0006]

In this manner, each drive shaft is accelerated / decelerated in accordance with the speed command having a predetermined acceleration / deceleration, and at the end of one tact time, the speed of the drive shaft is first settled to the original speed.
By eliminating the phase deviation during the remaining time and setting the drive shaft to the target phase, tuning phase control of a plurality of drive shafts that can easily achieve the target accuracy can be achieved.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a graph showing an example of a speed command pattern generated by one embodiment of a speed command generation method in servo system tuning phase control of the present invention. In this case, the tact time is 0.1 as in the case of FIG.
First, the value of the speed command Vref is linearly decelerated from 2.6811 m / sec in the normal rotation direction to a stop speed 0 m / sec with the normal rotation deceleration time Td ₁ of 0.036 sec (curve 1), and subsequently. 2.6681 in the reverse direction
Up to m / sec, the reverse acceleration time Ta ₂ is 0.036 sec.
To accelerate linearly (curve 2). Next, 0.
After maintaining the speed at 2.6811 m / sec for 018 sec (curve 3), deceleration is started, and the reverse rotation deceleration time Td ₂
At 0.036 sec, linearly decelerates again to the stop speed of 0 m / sec (curve 4). Subsequently normal rotation acceleration time Ta ₁ in the forward direction is linearly accelerated at 0.036Sec, returns to the original value of the forward direction of the velocity 2.6811m / sec (curve 5). In this case, the period of 0.018 sec (curve 6) remaining before the end point A is a sufficient time margin to eliminate the delay in correcting the phase due to the speed change.

[0008] The acceleration and deceleration of the speed command Vref are defined as GD ² [kg · m ² ] of the motor shaft of the load machine and GD ^{2 of the} drive motor for each of the plurality of drive shafts.
And [kg · m ^2] Total GD ² and [kg · m ^2] of the drive motor minimum acceleration time and minimum deceleration can be more calculated to the rated torque T ₁₀₀ [kg · m] and the rated speed N ₁₀₀ [rpm] of the Set so that acceleration / deceleration ends in time. Alternatively, the acceleration / deceleration may be completed in a time slightly longer than the minimum acceleration / deceleration time as long as a time margin for the phase correction before the point A is obtained.

[0009]

As described above, according to the present invention, the speed of the drive shaft is returned to the speed at the start time just before the end of one tact time, and the phase can be corrected during the remaining time. As described above, by adjusting the acceleration / deceleration of the speed command value during the elapse of the tact time, the speed command is generated, so that the parameters of the control system can be easily determined, and the accuracy of the tuning phase control can be increased. In addition, since the configuration of the entire control system can be simplified, the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a graph showing an example of a speed command pattern generated according to an embodiment of the present invention.

FIG. 2 is a graph showing an example of a speed command pattern used for conventional tuning phase control.

[Description of Signs] 1, 2, 3, 4, 5, 6 Speed command curve Vref Speed command value (m / sec) Td ₁ Forward rotation deceleration time (sec) Ta ₂ Reverse rotation acceleration time (sec) Td ₂ Reverse rotation end of deceleration time (sec) Ta ₁ forward rotation acceleration time (sec) a cycle time

Claims (1)

(57) [Claims] In a servo system for calculating phase information of each of a plurality of drive axes from an input speed command and performing tuning phase control of the drive axes, a speed command that repeats the same pattern at every constant tact time is provided. In the generation method, during the elapse of one tact time, the time before the end time of the tact time is at least necessary for the phase of the drive shaft to return to the phase at the start time of the tact time at the end time of the tact time. By the time, the speed of the drive shaft reaches the speed at the start of the tact time,
A method for generating a speed command, comprising adjusting an acceleration and a deceleration of a speed command curve.