JP2001092518A - Method of controlling acceleration/deceleration of fast forwarding speed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fast forwarding speed acceleration/deceleration controlling method capable of suppressing a sudden acceleration change on the way of decelerating a feed shaft motor which becomes a vibration generation factor in a machine driving system and executing drive control at stable decelerating acceleration even when fast forwarding is executed at a high speed. SOLUTION: The first control method for dividing a current speed FC by prescribed decelerating acceleration dTb at the time of judging that a decelerated moving distance Ld exceeds a remaining moving distance Le and executing decelerating operation control by changing the acceleration dTb on the basis of the divided result or the second control method for calculating decelerating acceleration dTc on the basis of a deceleration fraction distance L to be a difference between the decelerated moving distance Ld and the remaining moving distance Le and the prescribed decelerating acceleration dTb, executing the first decelerating operation control by the decelerating acceleration dTc and executing succeeding decelerating operation control by the decelerating acceleration dTb is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a rapid traverse speed acceleration / deceleration control method used for positioning interpolation control of a numerically controlled machine tool.

[0002]

2. Description of the Related Art Conventionally, in a method for controlling acceleration and deceleration of a rapid traverse speed in a numerically controlled machine tool, as shown in a speed diagram of acceleration and deceleration control in the prior art shown in FIG. 6, a target speed Fmax is determined based on a predetermined acceleration dTa. An acceleration calculation control unit for controlling acceleration, a current speed Fc and a predetermined deceleration dT
b, a deceleration movement distance calculation control unit for calculating a deceleration movement distance Ld required from the stop to a stop, a remaining movement distance calculation unit for calculating a remaining movement distance Le from a current position to a target position, and the deceleration movement distance Ld Is determined to exceed the remaining travel distance Le, a deceleration calculation control unit that executes deceleration calculation control of the current speed using the deceleration dTb, and sets the interpolation speed to the target speed Fmax during fast-forward interpolation control. In this method, acceleration / deceleration control is performed on the target position, and interpolation control to a target position is performed using the calculated interpolation speed.

[0003]

In recent years, it has been desired to reduce the rapid traverse movement time, which is a non-cutting time, in order to shorten the operation time. We are working on further shortening. However, according to the conventional acceleration / deceleration control method described above, there are few cases where the remaining movement distance Le from the current position to the target position coincides with the deceleration movement distance Ld required for stopping, and the speed line La in FIG. As shown in the section Ts, the deceleration calculation may be temporarily interrupted during the deceleration calculation control, and the deceleration temporarily becomes zero during the deceleration. As a result, the deceleration torque for controlling the feed shaft motor of the numerically controlled machine tool fluctuates remarkably during the deceleration, causing a vibration of the mechanical drive system and a hindrance to high acceleration / deceleration.

SUMMARY OF THE INVENTION The present invention has been made under the above circumstances, and an object of the present invention is to suppress rapid acceleration fluctuation during the deceleration of a feed shaft motor, which causes vibration of a mechanical drive system, and to perform rapid traverse at high speed. It is an object of the present invention to provide a rapid traverse speed acceleration / deceleration control method capable of performing drive control with stable deceleration.

[0005]

According to the present invention, there is provided a deceleration movement distance calculation control unit for calculating a deceleration movement distance Ld required from a current speed Fc of a feed shaft and a predetermined deceleration dTb to a stop, and Moving distance L from the position to the target position
e, the remaining travel distance calculation unit for calculating the current speed Fc
And a deceleration calculation control unit for executing deceleration calculation control when it is determined that the deceleration movement distance Ld exceeds the remaining movement distance Le when the movement calculation is performed. The first object of the present invention is to divide the current speed Fc by the deceleration dTb when it is determined that the deceleration travel distance Ld exceeds the remaining travel distance Le. Division result N
When it is determined that there is a surplus, the deceleration dTb
Is changed to the deceleration change acceleration dTb ′ calculated by the following equation (1), and the deceleration calculation control is executed.

[0006]

DTb '= Fc / (N + 1) Alternatively, as a second method, when executing the deceleration calculation control, the deceleration fraction distance L, which is the difference between the deceleration movement distance Ld and the remaining movement distance Le, and the The deceleration dTc is calculated based on the deceleration dTb, and the deceleration dTc is calculated.
Performs the first deceleration calculation control, and the subsequent deceleration calculation control is achieved by executing the deceleration calculation dTb.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an example of a numerical control device to which the present invention is applied.
And transmitted by the interpolation control unit 2 and the speed unit amount calculation unit 5. The speed unit amount calculation unit 5 performs acceleration / deceleration calculation of the moving speed unit amount in accordance with the fast-forward command to perform acceleration / deceleration control of the interpolation speed to the target position.

The deceleration moving distance calculating section 6 calculates a current moving speed unit amount calculated by the speed unit amount calculating section 5, a deceleration unit amount (unit amount of deceleration for acceleration) dTb set by parameters (not shown) and the like. Then, the deceleration moving distance Ld required for deceleration is calculated. The remaining movement distance calculation unit 7 calculates a remaining movement distance Lc that is a difference between the target position commanded by the program analysis unit 1 and the interpolation position calculated by the interpolation control unit 2. The comparison operation unit 8 calculates the calculated deceleration moving distance L
By comparing d with the remaining travel distance Lc, the deceleration timing is detected, and when it is determined that deceleration is necessary, the deceleration unit amount calculation unit 9 uses a method described later to change the deceleration unit amount (deceleration change acceleration) dT.
b ′ is calculated and sent to the speed unit amount calculation unit 5 as a deceleration unit amount for deceleration control. The interpolation control unit 2 performs interpolation control of the rapid traverse speed toward the instructed target position based on the acceleration / deceleration calculation result of the speed unit amount calculated by the speed unit amount calculation unit 5, and via the axis drive control unit 3. Drive shaft motor 4
To control the position of the feed shaft.

FIG. 2 shows a detailed control method for the deceleration control of the rapid traverse speed in the numerically controlled machine tool described above.
This will be described with reference to the flowchart of FIG. The flowchart of FIG. 2 shows the first control method of the present invention, and the flowchart of FIG. 3 shows the second control method.

First, the first control method will be described with reference to the flowchart of FIG.

In the interpolation control unit 2, as an initial setting process,
The target value Pc analyzed by the program analysis unit 1 and the current positioning speed command Fc are set (step S).
1, S2). Subsequently, the remaining movement distance Lc up to the target value Pc
Is calculated by the following equation 2 (step S3), and the deceleration moving distance Ld is calculated by the following equation 3 (step S4).

[0013]

## EQU2 ## Remaining moving distance Lc = Pc-Pa-Fc where Pa = current value (interpolated position)

## EQU3 ## Next, the remaining movement distance Lc is compared with the deceleration movement distance Ld (step S5). If the remaining movement distance Lc is large, there is no need to decelerate yet. And the process proceeds to step S11. When the remaining movement distance Lc becomes smaller than the deceleration unit amount Ld, it is determined that deceleration is necessary, and the current speed Fc is changed to the deceleration d.
Tb, when it is determined that there is no remainder in the division result N, the division result N is determined as the number of deceleration operations N, and when it is determined that there is a remainder in the division result N, the division result N
Is incremented by 1 to determine the number N of deceleration calculations (step S6).
~ S8). Subsequently, as shown in Equation 1, the current speed command Fc is divided by the number of deceleration calculations N to calculate a deceleration unit amount dTb ′ for each unit calculation as a deceleration acceleration (step S9). From the speed Fc, the deceleration unit amount dTb '
Is subtracted (step S10). Then, the interpolation position Pa
Is added to the calculated current speed Fc (step S
11) Until the interpolation position Pa matches the target value Pc (step S12), the operations of steps S3 to S11 are repeated, and speed control or interpolation control is performed toward the target value Pc.

FIG. 4 shows a speed state at the time of fast-forward interpolation when the above-described first control method is applied, corresponding to the conventional example of FIG. As shown by the speed line La in FIG. 4, if the first control method is applied, the speed of the axis feed motor is controlled at a constant deceleration dTb ′, so that the conventional temporary deceleration calculation is performed. Abrupt acceleration fluctuations due to the interruption of the operation can be eliminated, and the occurrence of vibration of the mechanical drive system can be suppressed.

Next, the second control method will be described with reference to the flowchart of FIG.

In the interpolation control unit 2, as an initial setting process,
The target value Pc analyzed by the program analysis unit 1 and the current positioning speed command Fc are set (step S).
21, S22). Subsequently, the remaining movement distance L up to the target value Pc
c is calculated by the above equation 2 (step S23), and the deceleration moving distance Ld is calculated by the above equation 3 (step S2).
4).

Next, the remaining movement distance Lc and the deceleration movement distance Ld
(Step S25), and when the remaining movement distance Lc is large, it is determined that deceleration is not necessary yet, and Step S3 is performed.
Proceed to 1. If the remaining movement distance Lc is smaller than the deceleration movement distance Ld, it is determined that deceleration is necessary, and the subsequent step S27
Judge the deceleration start flag set in step (step S
26) If the deceleration start flag is not ON, it is time to start deceleration, and the process proceeds to step S27.
If the deceleration start flag is not ON, the deceleration has already been started, and the process proceeds to step S30. Step S2 above
If it is determined in step 6 that deceleration has started, the deceleration start flag is turned on (step S27), and the first deceleration dT
c is calculated by the following equation 4 (step S28).

[0018]

## EQU4 ## Initial deceleration dTc = (deceleration dT
b)-(deceleration fraction distance L) / (deceleration control frequency T) where deceleration fraction distance L = remaining travel distance Lc + current speed Fc-deceleration travel distance Ld deceleration control frequency T = current speed Fc / deceleration dTb Then, using the initial deceleration dTc obtained in step S28, the deceleration dTc from the current speed Fc is calculated.
Is subtracted to execute the first deceleration calculation at the start of deceleration (step 29).

If the deceleration has already started, the deceleration dTb is calculated from the current speed using the deceleration dTb.
Is subtracted to perform a deceleration calculation (step 30).

Then, the current speed Fc calculated as described above is added to the interpolation position Pa (step S31). Until the interpolation position Pa matches the target value Pc (step S3).
2), the operations of steps S23 to S31 are repeated,
Speed control or interpolation control is performed toward the target value Pc.

FIG. 5 shows a speed state at the time of fast-forward interpolation when the above-mentioned second control method is applied, corresponding to the conventional example of FIG. As shown by the speed line La in FIG. 5, if the second control method is applied, the deceleration control is first performed with the deceleration dTc, and thereafter, the deceleration dTb is constant.
By performing the deceleration control in this manner, it is possible to eliminate sudden acceleration fluctuations caused by temporary interruption of the deceleration calculation as in the related art, and to suppress the occurrence of vibration of the mechanical drive system.

[0022]

As described above, according to the present invention, the deceleration control is performed at a constant deceleration until deceleration without exceeding the deceleration dTb during deceleration, so that the fluctuation of the deceleration torque during deceleration is suppressed. In addition, it is possible to eliminate the vibration generation factor of the mechanical drive system. Therefore, even if high acceleration / deceleration is performed, stable acceleration / deceleration control can be performed, so that the rapid traverse movement time, which is a non-cutting time, can be reduced, which is effective in reducing the machine operation time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a numerical control device to which the present invention has been applied.

FIG. 2 is a flowchart for explaining a first control method of the present invention.

FIG. 3 is a flowchart illustrating a second control method according to the present invention.

FIG. 4 is a velocity diagram of acceleration / deceleration control using a first control method according to the present invention.

FIG. 5 is a velocity diagram of acceleration / deceleration control using a second control method according to the present invention.

FIG. 6 is a velocity diagram of acceleration / deceleration control in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Program analysis part 2 Interpolation control part 3 Axis drive control part 5 Speed unit amount calculation part 6 Deceleration movement distance calculation part 7 Remaining movement distance calculation part 8 Comparison calculation part 9 Deceleration unit amount calculation part

Claims (2)

[Claims] 1. A deceleration movement distance calculation control unit for calculating a deceleration movement distance Ld required for stopping from a current speed Fc of a feed axis and a predetermined deceleration acceleration dTb, and a remaining distance from a current position to a target position. A remaining movement distance calculation unit that calculates the movement distance Le; and a deceleration calculation control that executes deceleration calculation control when it is determined that the deceleration movement distance Ld exceeds the remaining movement distance Le when the movement is calculated at the current speed Fc. The acceleration / deceleration control method of the rapid traverse speed of the numerically controlled machine tool comprising the following steps: when the deceleration moving distance Ld is determined to exceed the remaining moving distance Le, the current speed Fc is calculated by the deceleration dTb. When it is determined that there is a remainder in the division result N, the deceleration acceleration dTb is changed to a deceleration change acceleration dTb ′ calculated by the following equation to execute deceleration calculation control. Deceleration control method for a fast-forward speed, characterized in that the. dTb '= Fc / (N + 1) 2. A deceleration movement distance calculation control unit for calculating a deceleration movement distance Ld required for stopping from a current speed Fc of the feed shaft and a predetermined deceleration acceleration dTb, and a remaining distance from the current position to a target position. A remaining movement distance calculation unit that calculates the movement distance Le; and a deceleration calculation control that executes deceleration calculation control when it is determined that the deceleration movement distance Ld exceeds the remaining movement distance Le when the movement is calculated at the current speed Fc. The acceleration / deceleration control method for the rapid traverse speed of a numerically controlled machine tool comprising: a deceleration movement distance Ld when the deceleration calculation control is executed.
The first deceleration d based on the deceleration fraction distance L, which is the difference between the deceleration fraction Le and the remaining travel distance Le, and the deceleration dTb.
An acceleration / deceleration control method for a rapid traverse speed, wherein Tc is calculated, first deceleration calculation control is executed by the deceleration dTc, and subsequent deceleration calculation control is executed by the deceleration dTb.