JPH086627A - Feed speed controller of numerical controller - Google Patents

Abstract

PURPOSE:To increase or reduce a feed speed with permissible acceleration without depending upon the value of an orverride by interpolating the shape shown with a command shape according to the output of a comparing means in every constant cycle and making a feed override at the time of machining. CONSTITUTION:The command feed speed F inputted from an interpretation part 2 is multiplied by the override O and the command feed speed multiplied by the override O is outputted by a multiplication part 35. The speed is increased or reduced on the basis of a permissible feed speed Vmax and permissible acceleration Amax, and a command feed speed Fo' increased or reduced after the overriding is outputted from a command speed increase/reduction part 36. On the basis of the output and a limited speed Vs calculated by a limited speed increase/reduction part 31, a comparison part 37 compares a limited speed Vp at an interpolation position (p) and outputs smaller one as a unit quantity U to an interpolation part 4 to make the override at the time of machining. Therefore, the permissible acceleration can be increased or reduced without depending upon the value of the override.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed speed control device for a numerical control device, and more particularly to a feed speed control device for which feed override is applied in a numerical control device for performing interpolation after accelerating and decelerating a command feed speed. is there.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing an example of a conventional numerical control apparatus.

The interpreter 2 reads the command shape Shp of the machining trajectory and the command feed speed F from the machining program 1. The feed speed control device 30 includes a speed limit acceleration / deceleration unit 31 and a selection unit 3.
2, allowable feed speed storage unit 33, and allowable acceleration storage unit 3
4 and the comparison unit 310, the feed unit amount U accelerated and decelerated by the allowable acceleration Amax from the command shape Shp and the command feed speed F is output according to the interpolation position p. Interpolator 4
Outputs the servo command value and the interpolation position p by interpolating the command shape Shp at regular intervals based on the feed unit amount U. The servos 5X, 5Y, 5Z are servo motors 6X, 6Y, 6Z for each axis based on the servo command value input from the interpolation unit 4.
Drive.

Here, the elements inside the feed rate control device 30 will be described. The permissible feed speed storage unit 33 and the permissible acceleration storage unit 34 store the permissible feed speed Vmax and the permissible acceleration Amax, which are determined by the characteristics of the machine to be controlled. The speed limit acceleration / deceleration unit 31
The maximum speed at which the acceleration in the normal direction of the machining locus becomes equal to or less than the allowable acceleration Amax is calculated from the command shape Shp, and the upper limit thereof is limited by the command feed speed F, and then the acceleration / deceleration is performed at the allowable acceleration Amax in the tangential direction of the machining locus. Then, the speed limit Vs at the position on the processing locus is calculated. Selector 32
Selects the speed limit Vp at the interpolation position p from the speed limits Vs calculated at each position on the machining locus. Comparison unit 310
Compares the speed limit Vp with the allowable feed speed Vmax,
The one that is not larger is output as the feed unit amount U.

In the numerical control device as described above, since the acceleration / deceleration can always be performed by the allowable acceleration, the machining efficiency is good. However, since the numerical control device does not have the feed override function that is usually equipped, the operator cannot change the feed speed during machining, resulting in poor operability. The feed override function is a function that allows an operator to freely change the feed speed generally between 0% and 200% during processing, and the ratio is hereinafter simply referred to as an override. From this, a numerical controller as shown in the block diagram of FIG. 9 has been devised.

The numerical control device of FIG. 9 is obtained by newly adding an override acceleration / deceleration unit 38 and a multiplication unit 39 to the feed rate control device 30 of the numerical control device of FIG. The override acceleration / deceleration unit 38 performs acceleration / deceleration of the override O with a time constant Tc and outputs the accelerated / decelerated override O ′. The multiplication unit 39 multiplies the speed limit Vp at the interpolation position p by the override O ′ and outputs the overridden speed limit Vpo to the comparison unit 310.
The comparison unit 310 uses the speed limit Vpo and the allowable feed speed Vpo.
Max is compared, and the one that is not larger is output as the feed unit amount U. Processing program 1, interpretation unit 2, speed limit acceleration / deceleration unit 31, selection unit 32, allowable feed speed storage unit 33, allowable acceleration storage unit 34, interpolation unit 4, servos 5X, 5Y, 5Z. Since the servo motors 6X, 6Y, and 6Z are the same as the elements having the same reference numerals in FIG. 8, description thereof will be omitted.

FIG. 10 shows an example of the speed relating to the feed override function in the feed speed control device 300 when the override O is changed as shown in FIG. Figure 10
(A) is a figure which shows the value of the override O'which accelerated / decelerated by the override acceleration / deceleration part 38 with respect to the override O shown in FIG. Although the value of the override O changes stepwise in the middle, the override acceleration / deceleration unit 38
The value of the override O'accelerated and decelerated by the time constant Tc changes smoothly. FIG. 10B is a diagram showing the value of the speed limit Vp, and naturally the speed limit Vp is not overridden. FIG. 10C is a diagram showing the state of the feed unit amount U. The feed unit amount U when the speed limit Vp shown in FIG. 10B is multiplied by the override O ′ shown in FIG. 10A. Indicates the value of. As described above, when the override O is changed, the feed unit amount U can be changed smoothly and immediately by applying the accelerated / decelerated override O ′.

[0008]

However, the conventional feed rate control device of the numerical control device as described above has the following problems.

FIG. 11 is a diagram showing another example in which the override O is the same as that in FIG. 10 (FIG. 4) but the speed limit Vp is different. In this case, the override O'of FIG. 11 (a) is the same as that of FIG. 10 (a). FIG. 11B is a diagram showing the value of the speed limit Vp. FIG. 11C is a diagram showing the state of the feed unit amount U, in which the speed limit Vp shown in FIG. 11B and the override O ′ shown in FIG.
It shows the value of the feed unit amount U when multiplied by.

The inclination α'in FIG. 11 (c) shows the acceleration of the feed unit amount U caused by the acceleration / deceleration of the speed limit Vp when the override O'is 50%. As can be seen from the figure, when the override O ′ is less than 100%, the acceleration α ′ of the feed unit amount U caused by the acceleration / deceleration of the speed limit Vp becomes smaller than the allowable acceleration Amax. Although not shown, on the contrary, if the override O ′ exceeds 100%, the acceleration becomes larger than the allowable acceleration Amax.

Further, the slope β'in FIG. 11 (c) indicates the acceleration of the feed unit amount U caused by the acceleration / deceleration of the override O'when the speed limit Vp is constant. As can be seen from the figure, the acceleration / deceleration time constant T of the override O '
Since c is a constant value, the acceleration β ′ of the feed unit amount U caused by the acceleration / deceleration of the override O ′ does not match the allowable acceleration Amax when the speed limit Vp is constant.

FIG. 12 is a diagram showing an example in which the speed limit Vp is smaller than that in FIG. Also in this case, FIG. 12A showing the override O ′ is the same as FIG. 10A, and the description thereof will be omitted. FIG. 12B is a diagram showing the value of the speed limit Vp. FIG. 12C is a diagram showing a state of the feed unit amount U, and the speed limit Vp shown in FIG.
The value of the feed unit amount U when the override O ′ shown in 2 (a) is applied is shown.

The inclination α'in FIG. 12 (c) is given by FIG. 11 (c).
Since it has the same property as the inclination α ′ of, the description thereof will be omitted.

The slope γ'in FIG. 12 (c) is determined by the speed limit Vp.
Shows the acceleration of the feed unit amount U caused by the acceleration / deceleration of the override O ′ in the case of a fixed value smaller than that of FIG. 11 (c). As shown in the figure, when the speed limit Vp is constant, the acceleration γ ′ of the feed unit amount U caused by the acceleration / deceleration of the override O ′ becomes smaller as the speed limit Vp becomes smaller. Become.

FIG. 13 is a diagram showing an example of the speed relating to the feed override function when the override O is changed as shown in FIG. 5 at the start of acceleration of the speed limit Vp. FIG. 13A is a diagram showing a value of the override O ′ obtained by performing acceleration / deceleration on the override O shown in FIG. 5 by the override acceleration / deceleration unit 38. FIG. 13B is a diagram showing the value of the speed limit Vp. FIG. 13C is a diagram showing the state of the feed unit amount U. The feed unit amount U when the speed limit Vp shown in FIG. 13B is multiplied by the override O ′ shown in FIG. 13A. Indicates the value of.

The slope δ'in FIG. 13 (c) is determined by the speed limit Vp.
2 shows the maximum value of the acceleration of the feed unit amount U caused by both acceleration and deceleration of the override O'and the override O '. When the override O'is accelerated or decelerated during acceleration / deceleration of the speed limit Vp, the acceleration of the feed unit amount U does not have a constant value, as indicated by the curved line AB. Further, as shown in the figure, the maximum value δ ′ of the acceleration may exceed the allowable acceleration Amax.

Therefore, the acceleration of the feed unit amount U during acceleration / deceleration of the override O'or when the value is other than 100% is not necessarily the allowable acceleration Amax, and when the acceleration is smaller than the allowable acceleration Amax. Since the time required for accelerating and decelerating the feed unit amount U becomes long, the machining efficiency is lowered, and when the allowable acceleration Amax is exceeded, a shock is given to the mechanical system.

The present invention has been made under the circumstances as described above, and an object of the present invention is to provide a numerical value that can perform feed override and can always perform acceleration / deceleration with an allowable acceleration regardless of the override value. It is to provide a feed rate control device for a control device.

[0019]

In order to achieve the above object, a feed rate control device of a numerical control device according to the present invention applies an operation according to a command shape of a machining program based on an allowable feed rate and an allowable acceleration. In the feed rate control device of the numerical control device that decelerates and outputs the speed limit according to the interpolation position to interpolate the shape represented by the command shape according to the speed limit, override the command feed speed of the machining program. Multiplying means for multiplying by, a command speed acceleration / deceleration means for accelerating / decelerating the output of the multiplication means based on the allowable feed speed and the allowable acceleration, and comparing the output of the command speed acceleration / deceleration means with the speed limit. And a comparison means for outputting the one that is not greater than the above, and the shape represented by the command shape is interpolated according to the output from the comparison means at regular intervals. And wherein applying an override feed during processing in Rukoto.

[0020]

According to the present invention, the comparison means is accelerated and decelerated by the allowable acceleration determined by the command speed acceleration and deceleration means by the allowable acceleration in the command feed speed overridden by the multiplication means and the allowable acceleration. By comparing with the speed limit and using the lesser one as the feed unit amount,
Feed override can be applied, and acceleration / deceleration can always be performed with the allowable acceleration regardless of the override value.

[0021]

FIG. 1 is a block diagram showing an embodiment of the present invention. The feed speed control device 3 includes a speed limit acceleration / deceleration unit 31.
A selection unit 32, an allowable feed speed storage unit 33, an allowable acceleration storage unit 34, a multiplication unit 35, and a command speed acceleration / deceleration unit 3
6 and a comparison unit 37. Details will be described later. Machining program 1, interpretation unit 2, selection unit 32, permissible feed rate storage unit 33, permissible acceleration storage unit 34, interpolation unit 4, servos 5X, 5Y, 5Z, servo motors 6X,
6Y and 6Z are the same as the elements having the same reference numerals in FIG.

The speed limit accelerating / decelerating section 31 is configured to control the command shape Shp.
Is the allowable acceleration Amax in the direction normal to the machining path
The following maximum speed is calculated, the upper limit thereof is limited by the allowable feed speed Vmax, and then the acceleration / deceleration is performed by the allowable acceleration Amax in the tangential direction of the machining locus to calculate the speed limit Vs at the position on the machining locus. It is a speed acceleration / deceleration means. The multiplying unit 35 multiplies the command feed speed F by the override O to obtain the overridden command feed speed Fo.
Is a multiplication means for outputting. The command speed acceleration / deceleration unit 36
This is a command speed acceleration / deceleration means for limiting the upper limit of the command feed speed Fo by the allowable feed speed Vmax, performing acceleration / deceleration with the allowable acceleration Amax, and outputting the command feed speed Fo ′ that has been accelerated / decelerated after overriding. The comparison unit 37 compares the command feed speed Fo ′ with the speed limit Vp input from the selection unit 32.
It is a comparing means for comparing the two and the one which is not larger and outputs it as the feed unit amount U.

A characteristic of this embodiment is that the multiplication unit 35 and the command speed acceleration / deceleration unit 36 are provided, and the comparison unit 37 is provided.
Since the command feed speed Fo 'and the speed limit Vp, whichever is not larger, is output as the feed unit amount U, the feed override can be applied and the acceleration / deceleration can always be performed with the allowable acceleration regardless of the override value. That's what I was able to do.

Next, the multiplication unit 35 and the command speed acceleration / deceleration unit 3
6 and the operation of the comparison unit 37 will be described. FIG. 2 is a flowchart showing a flow of processing performed by the multiplication unit 35 and the command speed acceleration / deceleration unit 36 in one cycle. The multiplication unit 35
The command feed speed F input from the interpreter 2 is overridden O to give the command feed speed F overridden.
o is output (step S11). Command speed acceleration / deceleration unit 3
6 is the allowable feed speed Vm input from the allowable feed speed storage unit 33 when the command feed speed Fo input from the multiplication unit 35 is input.
It is determined whether or not it exceeds ax (step S12),
If it exceeds, the value of the command feed speed Fo is set to the allowable feed speed Vm.
Set to ax (step S13). Next, command feed speed F
o is compared with the previously output command feed speed Fo '(step S14), and if the values are the same, the value of the command feed speed Fo' is made the command feed speed Fo without performing acceleration / deceleration (step S15). On the other hand, if the values are not the same, acceleration / deceleration is performed. That is, the command feed speed Fo and the previously output command feed speed F
o ′ is compared (step S16), and the command feed speed Fo is compared.
If is larger, acceleration is performed, and if smaller, deceleration is performed. The acceleration is the permissible acceleration Ama input from the permissible acceleration storage unit 34 to the previously output command feed speed Fo ′.
The value obtained by adding x is set as the command feed speed Fo '(step S
17), it is determined whether or not the value exceeds the command feed speed Fo (step S18), and if it exceeds, the value of the command feed speed Fo'is set to the command feed speed Fo (step S1).
9). For deceleration, a value obtained by subtracting the allowable acceleration Amax from the previously output command feed speed Fo ′ is set as the command feed speed Fo ′ (step S110), and it is determined whether the value is less than the command feed speed Fo (step S111). If it is less than this, the value of the command feed speed Fo'is set to the command feed speed Fo (step S112).

The command feed speed Fo ', which has been accelerated and decelerated after the overriding thus calculated, is output to the comparison section 37 (step S113).

FIG. 3 is a flow chart showing the flow of processing performed by the comparison unit 37 in one cycle. The comparison unit 37
Command feed speed F input from command speed acceleration / deceleration unit 36
o'and the speed limit Vp input from the selector 32 are compared (step S21), and if the command feed speed Fo 'is smaller, the value of the feed unit amount U is set to the command feed speed Fo' (step S22). If not, the value of the feed unit amount U is set to the speed limit Vp (step S23). Then, the calculated feed unit amount U is output to the interpolation unit 4 (step S24).

The feed rate control device 3 described so far
Examples of speeds relating to the feed override function in FIG. 6 (a) and 7 (a)
FIG. 6 is a diagram showing a value of a command feed speed Fo ′ when the override O is changed as shown in FIGS. 4 and 5, respectively. Although the value of the override O changes stepwise during the process, the command speed acceleration / deceleration unit 36 performs acceleration / deceleration by the allowable acceleration Amax on the command feed speed Fo to which the override O is applied to thereby obtain the command feed speed Fo ′. The value of changes with the allowable acceleration Amax. 6 (b) and 7
(B) is a figure which shows the value of speed limit Vp. Figure 6
(C) and FIG. 7 (c) are diagrams showing the state of the feed unit amount U, respectively, when the speed limit Vp is the value shown in FIG. 6 (b) and FIG. 7 (b), respectively. 6 (a) and FIG. 7 (a) show the value of the feed unit amount U when the command feed speed Fo 'changes. As can be seen from the figure, the acceleration α of the feed unit amount U caused by the acceleration / deceleration of the speed limit Vp, the acceleration β of the feed unit amount U caused by the acceleration / deceleration of the command feed speed Fo ′, and the command feed speed F
The acceleration δ of the feed unit amount U caused by both acceleration and deceleration of both o'and the speed limit Vp is equal to the allowable acceleration Amax.

As described above, according to the feed speed control device of the present invention, the command feed speed Fo 'accelerated and decelerated by the allowable acceleration Amax is compared with the speed limit Vp, and the one that is not larger is set as the feed unit amount U. Therefore, even if either or both of the command feed speed Fo 'and the speed limit Vp are accelerated or decelerated, the acceleration of the feed unit amount U is always the allowable acceleration Amax.
Kept in.

[0029]

According to the feed rate control device of the numerical controller of the present invention, the feed override can be applied, and the acceleration / deceleration can always be performed with the allowable acceleration regardless of the override value, and the override change can be made. It is possible to minimize the reduction in processing efficiency due to.
It goes without saying that the impact on the mechanical system can be suppressed within an allowable range.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a flow chart for explaining an embodiment of the present invention.

FIG. 3 is a flow chart for explaining an embodiment of the present invention.

FIG. 4 is a diagram showing an example of overlay for explaining an example of the present invention and an example of a conventional technique.

FIG. 5 is a diagram showing an example of override for explaining an example of the present invention and an example of a conventional technique.

FIG. 6 is a diagram showing an example of speeds regarding a feed override function for explaining an embodiment of the present invention.

FIG. 7 is a diagram showing an example of speeds related to a feed override function for explaining an embodiment of the present invention.

FIG. 8 is a block diagram showing an example of a conventional numerical control device that does not have a feed override function that performs interpolation after performing acceleration / deceleration.

FIG. 9 is a block diagram showing an example of a conventional numerical control device having a feed override function that performs interpolation after performing acceleration / deceleration.

FIG. 10 is a diagram showing an example of speeds related to a feed override function for explaining an example of a conventional technique.

FIG. 11 is a diagram showing an example of speeds related to a feed override function for explaining an example of a conventional technique.

FIG. 12 is a diagram showing an example of a speed regarding a feed override function for explaining an example of a conventional technique.

FIG. 13 is a diagram showing an example of speeds related to a feed override function for explaining an example of a conventional technique.

[Explanation of symbols]

 1 Machining program 2 Interpretation unit 3, 30, 300 Feed rate control device 4 Interpolation section 31 Speed limit acceleration / deceleration section 32 Selection section 33 Allowable feed rate storage section 34 Allowable acceleration storage section 35 Multiplying section 36 Command speed acceleration / deceleration section 37 Comparison section 38 Override acceleration / deceleration unit 39 Multiplying unit 310 Comparing unit 5X, 5Y, 5Z servo 6X, 6Y, 6Z servo motor

Claims (1)

[Claims] 1. A shape represented by the commanded shape is restricted by performing acceleration / deceleration according to a commanded shape of a machining program on the basis of an allowable feed rate and an allowable acceleration and outputting a speed limit according to an interpolation position. In a feed rate control device of a numerical control device for interpolating according to a speed, a multiplying means for overriding a command feed speed of a machining program, and accelerating and decelerating the output of the multiplying means based on the allowable feed speed and the allowable acceleration Command speed acceleration / deceleration means, and a comparison means for comparing the output of the command speed acceleration / deceleration means with the speed limit and outputting the one that is not larger, the shape represented by the command shape is set at regular intervals. A feed speed control of a numerical controller characterized in that a feed override is applied during machining by interpolating according to the output from the comparison means. apparatus.