JP2001034319A - Locus controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make allocatable the same locus and moving speed to tools even though there is variation in a command program performing linear interpolation by allowing an extracting means to recognize the entire locus obtained by smoothing uncontinuous local changes included in an original command locus as the shape of a free curve and adjusting the moving locus and moving speed of a tool on the basis of it. SOLUTION: This locus controller 3 consists of three functioning parts which are a command program interpreting part 4, a locus controlling part 5 and a parameter σ setting part 6 and a data inputting part 7. The part 5 performs scale space filtering of an inputted command locus as an original command locus, recognizes a smoothed command locus obtained by this processing as being the shape characteristic quantity of a free curve with which linear interpolation is performed and sets a clamp speed on the basis of the shape characteristic quantity of the free curve. A control signal driving the servo motor of a tool machine 8 is outputted on the basis of the data of the command locus and the set clamp speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an NC machine tool and a trajectory control device for controlling the operation trajectory of a tool provided in an industrial robot such as an automatic transfer machine and an automatic assembling machine. The present invention relates to a trajectory control device suitable for improving the accuracy of the trajectory.

[0002]

2. Description of the Related Art Conventionally, a tool provided in an NC machine tool,
In addition, a trajectory control device that controls an operation trajectory of a tool included in an industrial robot such as an automatic transfer machine or an automatic assembly machine is known. The trajectory control device outputs a control signal of a servomotor that actually moves a tool included in the NC machine tool or the like based on a command program input from the outside.

The above command program (for example, G code
Data) is composed of data representing a movement locus of a tool to be controlled (hereinafter referred to as a command locus) and data of a moving speed of the tool, and is a CAM (Computer Aided Manufacturing).
Is generated based on a three-dimensional design drawing created by CAD or the like. When the free curve shown in the three-dimensional design drawing is used as a movement path, the CAM divides the free curve into minute sections, replaces the curve in the minute section with a line segment, and approximates the free curve with a polygonal line. Then, a command program for linearly interpolating the free curve with the approximated broken line is created. When creating the command program, the CAM sets the distance between the free curve and the polygonal line to fall within a predetermined error range.
The length and the number of line segments constituting the polygonal line are set.

[0004] In order to move the tool with high accuracy according to the free curve of the design drawing, the length of each line segment constituting the polygonal line should be shortened and the number thereof should be increased. However, the size of the instruction program increases with the increase in the number of line segments constituting the polygonal line. The increase in the size of the command program imposes a heavy burden on the processing of the NC machine tool, and a limit is imposed on the moving speed of the tool. For this reason, there arises a problem that the movement speed is unintentionally reduced.

In order to avoid the above problem, a trajectory control device has been proposed which replaces each segment of the polygonal line with an appropriate spline curve and outputs a control signal for spline interpolation of a free curve (for example, Japanese Patent Application Laid-Open No. 9-1997). No. 35054). The trajectory control device uses a spline curve to accurately move a tool according to the free curve of the blueprint, even when the free curve of the blueprint is roughly approximated by a few line segments. Can be. Also,
By using the spline curve, it is possible to prevent the occurrence of the unintended lowering of the moving speed as described above.

[0006]

In the above command program created by the conventional CAM, the same free curve is
Frequently, a minute line segment having a different length is connected by a different number to form a polygonal line (for example, refer to command trajectories A, B, and C in FIG. 9). In addition, the tool movement trajectory commanded by the command program may include a minute line segment irrelevant to the direction of the target trajectory due to a CAD or CAM calculation error (for example,
(See FIG. 13A).

In a conventional trajectory control device, if the description of a command program for linearly interpolating the same free curve on a design drawing varies due to the above-described factors, the tool of the machine tool is moved with the same trajectory and speed. Can not. This problem cannot be solved by assigning a spline curve to each line segment for performing linear interpolation in a conventional manner. The variation in the movement locus and the movement speed of the tool due to the variation in the description of the command program with respect to the same free curve has caused a decrease in the machining accuracy, particularly of the NC machine tool that performs metal working.

An object of the present invention is to move a tool of a machine tool along the same trajectory and speed with respect to the same free curve on a design drawing even when the description of a command program has variations due to the above factors. It is to provide a trajectory control device capable of performing the following.

[0009]

A first trajectory control device of the present invention is a trajectory control device for outputting a control signal for moving a tool of a machine tool with a trajectory and a speed specified by a command program. Extracting means for setting a movement locus of a tool instructed by the command program as an original command locus, smoothing discontinuous local changes included in the original command locus, and extracting an entire locus corresponding to the original command locus; Based on the shape of the entire trajectory extracted by the extraction means,
A control unit that performs at least one of the correction of the movement locus of the tool and the adjustment of the movement speed.

[0010] The second trajectory control device of the present invention includes the first trajectory control device.
In the trajectory control device, the control unit detects a line segment in a direction different from the shape of the entire trajectory extracted by the extraction unit by a predetermined angle or more as a defective line segment from the line segment in the movement trajectory. The method is characterized in that a nearby line segment including the defective line segment is replaced with a line segment that follows the shape of the extracted overall trajectory.

[0011] The third trajectory control device of the present invention comprises the first trajectory control device.
Wherein the control unit replaces each line segment in the movement trajectory with a spline curve based on the shape of the entire trajectory extracted by the extraction means.

According to a fourth trajectory control device of the present invention, the first
In the trajectory control device, the control means detects a line segment in a direction different from the shape of the entire trajectory extracted by the extraction means by a predetermined angle or more as a defective line segment from the line segment in the movement trajectory. Replacing nearby line segments including a defective line segment with a line segment along the shape of the extracted overall trajectory, and replacing each line segment in the replaced movement trajectory with a spline curve based on the extracted overall trajectory shape. It is characterized by.

According to a fifth trajectory control device of the present invention,
In any one of the trajectory control devices of the fourth to fourth aspects, further, an edge detection unit that detects an edge portion formed by a line segment other than a line segment that linearly interpolates a free curve, among the movement trajectories of the tool,
And a speed control means for reducing the moving speed of the tool when passing through the edge portion detected by the edge detection means in accordance with the angle of the edge portion.

The trajectory control device according to the sixth aspect of the present invention includes the fifth trajectory control device.
In the trajectory control device, the edge detecting means may detect an edge portion formed by a line segment having a predetermined length or more as an edge portion formed by a line segment other than a line segment for linearly interpolating a free curve. It is characterized by.

According to a seventh trajectory control device of the present invention,
5. The trajectory control device according to claim 4, wherein
In advance, for each line segment to be linearly interpolated, if a command program to which data on whether or not the line segment is to linearly interpolate a free curve is added is input, the data added to the command program is Based on, based on the edge portion specifying means for specifying an edge portion other than the line segment to linearly interpolate the free curve, the moving speed of the tool passing through the edge portion specified by the edge portion specifying means,
Speed control means for decelerating in accordance with the angle of the edge portion.

An eighth trajectory control device according to the present invention includes the first trajectory control device.
Any one of the trajectory control devices according to any one of the seventh to seventh aspects, further comprising: setting means for setting a parameter σ, wherein the extracting means sets a movement trajectory of a tool specified by a command program as an original command trajectory, and The method is characterized in that scale space filtering using a Gaussian function having a spread of the parameter σ set by is performed.

According to a ninth trajectory control device of the present invention,
Is characterized in that the parameter σ setting means sets the parameter σ according to the type and size of the tool used in the machine tool.

A tenth trajectory control device according to the present invention is the trajectory control device according to the eighth invention, wherein the parameter σ setting means sets the parameter σ in accordance with an input of data specifying the accuracy of the movement control of the tool of the machine tool. Is set.

According to an eleventh trajectory control device of the present invention, in the tenth trajectory control device, the parameter σ setting means is inputted as data for specifying the accuracy of the movement control of the tool of the machine tool. Is characterized in that the parameter σ is set based on the data of the interval of the movement trajectory used in.

A twelfth trajectory control device according to the present invention is the machine tool according to the tenth trajectory control device, wherein said parameter σ setting means is inputted as data for specifying the precision of the movement control of the tool of the machine tool. Is characterized in that the parameter σ is set based on the data of the moving speed of the tool used in.

According to a thirteenth trajectory control device of the present invention, the first to seventh trajectory control devices are arranged such that when a command program to which data of the parameter σ used in the extracting means is added in advance is input, A parameter σ specifying means for specifying a parameter σ used by the extracting means based on the data added to the command program, wherein the extracting means determines a movement trajectory of the tool specified by the command program by an original command trajectory. And the scale space filtering is performed using a Gaussian function having the parameter σ extracted by the parameter σ specifying means.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Outline of the Invention The trajectory control device of the present invention is used for an NC machine tool, an industrial robot, or the like that operates according to a command program. The command program includes a selection signal of a tool to be used, data representing a movement locus (hereinafter, referred to as a command locus) of a tool to be controlled, and data of a moving speed of the tool, like known G code data. Computer Aided Manufacturin
g) is generated based on a three-dimensional design drawing created by CAD or the like. When the free curve shown in the three-dimensional design drawing is used as a movement path, the CAM divides the free curve into minute sections, replaces the curve in the minute section with a line segment, and approximates the free curve with a polygonal line. Then, a command program for linearly interpolating the free curve with the approximated broken line is created.

The trajectory control device of the present invention uses a Watkin (AW
itkin), "Scale Space Filtering (Scale
space filtering), Proc. of 8th International Joint on Artifical In
telligence), pp1019-1022, 1983 ”, the shape of a free curve to be linearly interpolated using scale space filtering proposed, and the movement trajectory of the tool is corrected based on the recognized shape of the free curve. In addition, the moving speed of the tool is adjusted.

The scale space filter extends the original command trajectory to a set of waveforms obtained by various scales in order to express the waveform hierarchically. The waveform set is a set of waveforms obtained by convolving and integrating a Gaussian function in which the bandwidth is variously changed to the original command trajectory.

The scale space filtering is (−∞, ∞)
The original command trajectory f (x) given in the section of is expressed by a Gaussian function g having a spread σ, as shown in “Equation 1” below.
(X; σ) is converted into a continuous curve by smoothing by a convolution integral (see “Equation 2” below).

(Equation 1)

(Equation 2) The smoothed command trajectory f (x; σ) obtained by the scale space filtering has a shape obtained by removing a shape smaller than the parameter σ representing the spread of the Gaussian function from the original command trajectory.

FIG. 1 shows a smoothed command trajectory f with a change in a parameter σ representing the spread of a Gaussian function.
(X; σ) shows a change in shape. As is clear from the figure, as the value of the parameter σ increases, the fine structure of the original command trajectory is lost, leaving only the rough shape of the original command trajectory. Conversely, as the value of the parameter σ decreases, the details of the original command trajectory become clearer. As described above, the parameter σ indicating the spread of the Gaussian function functions as a scale indicating how rough the original command trajectory is when observing the waveform.

According to the trajectory control device of the present invention, the movement trajectory of the tool commanded by the command program is used as the original command trajectory, and discontinuous local changes included in the original command trajectory are smoothed and smoothed by scale space filtering. The command trajectory (the entire trajectory corresponding to the original command trajectory) is recognized as the shape feature of the free curve for performing linear interpolation, and the tool movement trajectory and the tool movement are determined based on the recognized free curve shape feature. It is characterized in that at least one of the speeds is corrected.

Any means that can smooth discontinuous local changes contained in the movement locus (original command locus) of the tool instructed by the command program and recognize the rough shape of the original command locus can be used. Means other than scale space filtering may be used. However, the Gaussian function is
The shape that did not appear when the scale parameter σ was small is the only kernel function that is mathematically guaranteed to be monotonic in that it never appears when the scale parameter σ is large, and the effect of using scale space filtering is significant.

The trajectory control device of the present invention further includes input of data on the type and size of the tool to be used (diameter φ of the tool), or data (pic feed width) specifying the accuracy of the tool movement control of the machine tool. And moving speed), the parameter σ representing the spread of the Gaussian function used in the scale space filtering is appropriately set, thereby enabling the movement control of the tool with the accuracy desired by the user. .

(2) First Embodiment (2-1) Features of Trajectory Control Device The trajectory control device according to the first embodiment is used as an NC device of an NC machine tool that operates according to a command program. The trajectory control device according to the first embodiment uses a movement trajectory of a tool commanded by a command program as an original command trajectory,
Recognize the smoothed command trajectory obtained by performing scale space filtering on the original command trajectory as a shape feature of a free curve for performing linear interpolation, and based on the recognized free curve shape feature. Thus, an upper limit value (hereinafter, referred to as a clamp speed) of the moving speed of the tool at each point on the moving path of the tool is set.

By adopting the above configuration, the first embodiment
The trajectory control device according to the present invention, during the command program, even if the same free curve is approximated by a polygonal line formed by connecting different numbers of line segments of different lengths, almost the same clamping speed, That is, the moving speed of the tool can be made substantially the same. Thereby, the processing accuracy of the NC machine tool can be improved.

(2-2) Configuration of Trajectory Control Device FIG. 2 shows an NC including the trajectory control device 3 according to the first embodiment.
FIG. 2 is a configuration diagram of a machine tool 1. The NC machine tool 1 includes a program output device 2, a trajectory control device 3, and a machine tool 8. The program output device 2 is a magnetic tape reader, reads a command program recorded on a magnetic tape, and outputs the read command program to the trajectory control device 3. The command program is well-known G code data, and describes information about the type and size of the tool 10 used in the machine tool 8, the movement trajectory of the tool 10, and the movement speed of the tool 10.

The trajectory control device 3 is a computer comprising a central processing unit and a memory (not shown). The trajectory control device 3 executes a control signal generation process based on an input command program, and performs servo control of the machine tool 8. A control signal for driving the motor 9 is output. The memory stores various tables and data such as relational expressions used in the control signal generation processing.

As shown in FIG. 2, the trajectory control device 3 includes a command program interpreting unit 4 implemented by software,
It comprises three functional units, a trajectory control unit 5 and a parameter σ setting unit 6, and a data input unit 7, which is a man-machine interface.

The command program interpreting section 4 converts the input command program into a format suitable for processing in the trajectory control section 5, outputs the converted data to the trajectory control section 5, and outputs the converted data from the command program. The type and diameter φ of the tool 10 used by the machine 8 are specified, and data representing the specified type and diameter φ of the tool 10 is output to the parameter σ setting unit 6.

As shown in FIG. 3, the data input unit 7 includes keys 11 and 12 for setting the type of the tool 10 to be used (tool A or tool B) and a lever 1 for specifying the diameter φ of the tool 10.
3 and a numeric keypad 14 for directly inputting the value of a parameter σ representing the spread of a Gaussian function used in scale space filtering. The data input unit 7 allows the user to
Type (tool A or tool B) and diameter φ of the tool 10 set by operating the keys 11 and 12 or the lever 13
Or the value of the parameter σ directly input by the ten keys 14 is output to the parameter σ setting unit 6.

The parameter σ setting unit 6 uses the table for specifying the optimum parameter σ corresponding to the type of the tool 10 and the diameter φ of the tool 10, and
And outputs the value of the parameter σ corresponding to the data representing the type and the diameter φ of the tool 10 input to the trajectory control unit 5. For example, a table for specifying a coefficient corresponding to a range that can be machined from the type of the tool 10 is prepared, and a value obtained by multiplying the coefficient specified by the table by the diameter φ of the tool 10 is output as the parameter σ.

When the parameter σ setting unit 6 inputs data on the type or diameter φ of the tool 10 via the data input unit 7 by a user operation,
The parameter σ is set based on the data on the type and the diameter φ of the tool 10 input from the data input unit 7 ignoring the data input from the command program interpreting unit 4 and the value of the set parameter σ is set. Output to the trajectory control unit 5.

The parameter σ setting unit 6 is operated via a numeric keypad 14 (see FIG. 3) of the data input unit 7.
When the value of the parameter σ is directly input, the input value of the parameter σ is output to the trajectory control unit 5 as it is.

The trajectory control unit 5 performs scale space filtering using the input command trajectory as an original command trajectory, and determines that the smoothed command trajectory obtained by the processing is a shape characteristic quantity of a free curve for linear interpolation. Recognition is performed, and the clamp speed is set based on the recognized shape characteristic amount of the free curve. Note that the scale space filtering is performed using a Gaussian function having a spread of the parameter σ input from the parameter σ setting unit 6. The trajectory control unit 5 outputs a control signal for driving a servo motor 9 included in the machine tool 8 based on the command trajectory and data of the set clamping speed.

The machine tool 8 includes a servomotor 9 and a tool 10 whose movement is controlled by the servomotor 9. The servomotor 9 moves the tool 10 based on a control signal input from the trajectory control device 3.

(2-3) Modification of Setting of Parameter σ As described above, the parameter σ of the trajectory control device 3 is
The setting unit 6 specifies the value of the parameter σ based on the type of the tool 10 and the diameter φ of the tool 10. However, the parameter σ may be set based on information other than the data of the type of the tool 10 and the diameter φ of the tool 10, for example, information on the accuracy of the movement control of the tool 10. Below, the parameter σ
Modifications 1 to 3 of the setting will be described.

(2-3-1) Modification 1 of Setting of Parameter σ Pick feed width of cutting by the tool 10, that is, the tool 1
The movement interval of 0 is set narrow when high processing accuracy is required. Conversely, if the accuracy is not so required, it is set to be wider. Paying attention to the relationship between the pick feed width and the required machining accuracy, the command program interpreting unit 4 calculates the value of the pick feed width for cutting from the command program, and the obtained pick feed width value is used as the parameter σ setting unit 6. Is adopted.

In this case, the parameter σ setting unit 6 may output the input pick feed width as it is to the trajectory control unit 5 as the parameter σ, or may set an appropriate parameter σ corresponding to the pick feed width obtained above. A configuration may be adopted in which the specified parameter σ is specified using a predetermined table and the specified value of the parameter σ is output to the trajectory control unit 5.

The data input section 7 may be provided with a pick feed width setting lever. In this case, the parameter σ
The setting unit 6 ignores the pick feed width data output from the command program interpreting unit 4 and
The parameter σ is set based on the pick feed width set in.

(2-3-2) Modification 2 of Setting of Parameter σ When the moving speed of the cutting tool 10 provided in the machine tool 8 is set to a high speed, the processing time is shortened compared to the high-precision processing. It can be determined that it is desired. In this case, the value of the parameter σ is set to a large value to roughly grasp the shape of the original command trajectory, and the delay of the moving speed of the tool 10 due to the clamp speed set based on the fine shape is reduced. For example, a configuration is adopted in which the command program interpretation unit 4 outputs data on the moving speed of the tool 10 commanded from the command program to the parameter σ setting unit 6.

The parameter σ setting unit 6 may output the movement amount per interpolation cycle converted from the moving speed of the cutting tool 10 as it is as the parameter σ, or may use a predetermined table to A configuration in which an appropriate parameter σ corresponding to the moving speed of the cutting tool 10 is specified, and the value of the specified parameter σ is output to the trajectory control unit 5 may be adopted.

The data input unit 7 may be provided with a lever for setting a correction rate of the moving speed of the tool 10 specified by the command program. In this case, the parameter σ setting unit 6 outputs the tool 10
The parameter σ is set based on the speed obtained by multiplying the moving speed by the correction ratio set by the correction ratio setting lever of the data input unit 7.

(2-3-3) Modification 3 of Setting of Parameter σ A tool for specifying in advance the type and size (diameter φ) of the tool 10 to be used and the accuracy of the movement control of the tool 10 of the machine tool 8 A command program to which data of the optimum parameter .sigma. Specified in consideration of at least one of the moving speed and the pick feed width of No. 10 is prepared. In this case, the command program interpretation unit 4 extracts the value of the parameter σ added to the command program, and outputs the extracted value of the parameter σ to the trajectory control unit 5.

(2-4) Configuration of Trajectory Control Unit FIG. 4 is a functional block diagram of the trajectory control unit 5. The trajectory control unit 5 includes a scale space filtering unit 16, a clamp speed calculating unit 17, and a control signal generating unit 18. The command trajectory data is input to the scale space filtering means 16 and the control signal generating means 18.

The scale space filtering means 16 executes scale space filtering to smooth discontinuous local changes in the command trajectory. Specifically, convolution integration of the original command trajectory and a Gaussian function having a spread of the parameter σ input from the parameter σ setting unit 6 is performed, and the data of the smoothed command trajectory obtained by the calculation is obtained.
It is output as a feature quantity representing the shape of the free curve to be linearly interpolated.

The clamp speed calculating means 17 calculates the clamp speed based on the shape feature output from the scale space filtering means 16. Note that the clamp speed refers to the upper limit of the moving speed when the tool 10 passes a certain point of interest.

The control signal generating means 18 controls the moving speed of the tool 10 based on the clamp speed calculated by the clamp speed calculating means 11 and the command locus of the tool 10 based on the data of the command locus of the tool 10. It outputs a control signal for the servo motor 9 provided.

(2-5) Scale Space Filtering Processing The scale space filtering executed by the scale space filtering means 16 will be described in detail below. Of (a) is 5, (in the figure, the origin) target point of a command trajectory the way L on the trajectory from the obtained by axial decomposed in the X-axis, the relationship between the road L and the displacement amount H _x Represent. Less than,
The command trajectory disassembled for the X axis is defined as the original command trajectory. The original command trajectory is represented by the following “Equation 3”.

(Equation 3) FIG. 5B shows a Gaussian function having a spread specified by the parameter σ. The Gaussian function is represented by the following “Equation 4”
It is represented by

(Equation 4) FIG. 5C shows a smoothed trajectory H _x (L, σ) obtained by convolving the Gaussian function shown in FIG. 5B with respect to FIG. 5A. The waveform is obtained by convolution integration of “Equation 3” and “Equation 4” as represented by the following “Equation 5”.

(Equation 5) The above “Equation 5” is obtained by using the above “Equation 3” to obtain the next “Equation 6”.
Can be expanded as follows.

(Equation 6) The above “Equation 6” is an equation representing the smoothed trajectory H _x (L, σ).

[0055] As with the X axis for the Y-axis, (in the figure, the origin) target point of a command trajectory a waveform representing the relation between road L on the locus and the displacement amount H _y from the original command trajectory Locus H smoothed by performing scale space filtering
_y (L, σ) is obtained. The above two smoothed trajectories H _x
By synthesizing (L, σ) and H _y (L, σ), it is possible to obtain data of the shape characteristic amount of a free curve to be linearly interpolated in the spatial coordinates including the X axis and the Y axis.

In order to accurately calculate the smoothed command trajectory, the convolution integral must be finely executed over the entire section in which the linear interpolation is performed. However, from the viewpoint of examining the clamp speed at a certain point of interest, it is not necessary to do so. For example, scale space filtering is performed on a total of three points, that is, a point of interest and two points in the vicinity of the point of interest, to estimate the curvature of a free curve that is linearly interpolated by an arc passing through the obtained three points, and the clamp speed is calculated from the estimated curvature. You may ask.

A circle in FIG. 5C indicates a point H _x (0; σ) in which the attention point H _x (0) represented by a circle in FIG. Represents. This is L of "Equation 5".
Is substituted for 0, and is represented by the following “Equation 7”.

(Equation 7) The above “Equation 7” is obtained by using the above “Equation 3” to obtain the next “Equation 8”.
Can be expanded as follows.

(Equation 8) Point the "number 8" was smoothed point of interest H _x (0) H _x
(0; σ). It should be noted that the value of the Gaussian function decreases as the distance from the center to the periphery increases, and the Gaussian function hardly affects the operation result as the position approaches the periphery. For this reason, it is not necessary to calculate over the entire range from -∞ to ∞. For example, if the calculation is performed within a range of about three times the parameter σ of the Gaussian function, a sufficient approximate value can be obtained.

Hereinafter, a specific calculation method of Expression 8 will be described. First, the Gaussian function G (ξ; σ) and ξ ·
The integration result of G (ξ; σ) from 0 to L is stored in advance as a data table in a memory (not shown) configuring the trajectory control device 3. If you use this table,
With a small amount of calculation, it is possible to easily obtain a mathematical expression of a command locus that is smoothed around the point of interest.

FIG. 6A is a graph showing the value of G (L) with respect to the distance L from the point of interest, and FIG. 6B is a graph showing the value of G (ξ) with respect to the distance L from the point of interest. It is a graph showing the integrated value from 0 to L.

FIG. 6C is a data table showing the integral values of G (ξ) from 0 to L for the distance L from the point of interest. Note that the Gaussian function is an even function,
In the memory, for example, only the data of the integral value in the range of L from 0 to 3σ (where σ> 0) may be stored as a data table. For example, the integral value of G (L) from σ to 3σ can be calculated from the integral value of G (L) from 0 to 3σ to the integral value of G (L) from 0 to σ, as shown in the following Expression 9. It is obtained by subtracting the value of the integral value of.

(Equation 9)

In the above example, a case has been described in which command trajectories decomposed for each axis are treated as original command trajectories. However, scale space filtering is defined not only for one dimension but also for n dimensions. Thus, the n-dimensional command trajectory may be subjected to scale space filtering as it is. For example, the two-dimensional Gaussian function g (x, y; σ) is represented by the following “Equation 10”.

(Equation 10) The scale space filtering for the two-dimensional waveform f (x, y) is defined by the convolution shown in the following “Equation 11”.

[Equation 11] By calculating the above “Equation 11”, it is possible to directly obtain the data of the shape feature amount of the free curve on which the linear interpolation is performed in the spatial coordinates including the X axis and the Y axis.

(2-6) Control Signal Generation Process FIG. 7 is a flowchart of the control signal generation process executed in the trajectory control unit 5. First, a point of interest is selected (step S1). The point of interest is selected from the contact points of the line segments for performing linear interpolation in the command trajectory. The parameter σ setting unit 6 sets a line segment near the selected point of interest as an original command locus.
The convolution integration of the specified spread parameter σ with the Gaussian function is performed to perform scale space filtering (step S2). The clamp speed is calculated based on the smoothed command trajectory obtained by the scale space filtering (step S3). The details of the clamp speed calculation process will be described later. Step S above
The control signal of the servomotor 9 for moving the tool 10 along the command locus is output based on the clamp speed calculated in Step 3 (Step S4). When the processing has been completed for all the points to be treated as the point of interest among the contact points of the line segments for which the linear interpolation is performed (YES in step S5), the processing ends. On the other hand, if the processing for all the points to be treated as the point of interest has not been completed (step S5).
NO), the next point to be treated as the point of interest is set as a new point of interest (step S6), and the process returns to step S2. Note that, in step S6, a contact located one or a predetermined number of times next to the target point may be set as the next target point, or a contact separated from the target point by a predetermined distance or more may be set as the next target point. .

FIG. 8 is a flowchart of the clamp speed calculation processing (FIG. 7, step S3). First, the smoothed command trajectory obtained by the scale space filtering is recognized as a free curve for linear interpolation, and the curvature near the point of interest is calculated (step S10). According to the characteristics of the machine tool 8 to be used, the maximum speed at which the tool 10 can pass with high accuracy at the calculated curvature is set as the clamping speed at this point of interest (step S11). The tool 10 for which the clamp speed near the point of interest calculated in step S11 is set in advance in the command program
Is slower than the moving speed (YE in step S12).
S), after setting the clamp speed calculated in the above step S11 to the moving speed of the tool 10 when passing through the point of interest (hereinafter, referred to as an interpolation speed) (step S13),
To return. On the other hand, if the calculated clamping speed is equal to or higher than the moving speed of the tool 10 preset in the command program (NO in step S12), the process returns after setting the moving speed of the tool 10 to the interpolation speed (step S14).

If the input command trajectory bends in the same direction (not zigzag), the smoothed command trajectory will be drawn inside the original command trajectory, and the curvature of the smoothed command trajectory will be linear interpolation. Tend to be slightly tighter than the curvature of the free curve. In order to cope with such a case, it is preferable to prepare a relational expression or a table for obtaining the clamp speed from the curvature of the smoothed command trajectory for each type of the smoothed command trajectory. In this case, in step S11, first, type determination is made as to whether the smoothed command trajectory is bent in the same direction or zigzag, and the clamping speed is determined using a relational expression or table for the determined type. I do.
The above type of determination may be made, for example, based on the inclination of the tangent at each point of interest on the smoothed command trajectory. By adopting this configuration, it is possible to perform more appropriate control of the tool 10 for each type of the waveform of the free curve on which the linear interpolation is performed, thereby realizing highly accurate machining.

Further, it is preferable to prepare a relational expression or a table for obtaining the clamping speed from the curvature of the shape characteristic amount for each type of the machine tool 8 or the tool 10 to be used. In this case, in step S11, the machine tool 8 to be used is
Alternatively, the clamping speed is determined using a relational expression or a table instructed by the type of the tool 10. The machine tool 8
The type may be determined, for example, by providing a setting key on the data input unit 7 and inputting the key. The type of the tool 10 may use data input to the parameter σ setting unit 6. By adopting the configuration, more appropriate control of the tool 10 can be performed for each machine tool 8 or tool 10 to be used, and high-precision machining can be realized.

(2-7) Effect In the first row from the top in FIG. 9, command trajectories A, A, which are commanded by a command program created based on the same free curve,
B and C are shown, and the second row shows smoothed command trajectories A, B, and C obtained by performing scale space filtering on the command trajectories A, B, and C. The smoothed command trajectories A, B, and C can be recognized as expressing the shape of a free curve to be linearly interpolated. As shown in the figure, the command trajectories A, B, and C smoothed by the scale space filtering describe almost the same trajectory.

For example, the refractive index of the line segment at each point of interest (the contact point of the line segment) of the commanded trajectory A is larger than that of each point of interest of the commanded trajectories B and C. In the conventional trajectory control measures for setting the clamping speed based on the bending rate of each point of interest, a lower clamping speed than the command trajectories B and C is set at each point of interest of the command trajectory A. On the other hand, in the trajectory control device 3, the clamp speed of each target point of the command trajectory A is
It is set based on the curvature of the position corresponding to the noted point on the smoothed command locus A. As described above, the shape of the smoothed command trajectory A is the same as that of the smoothed command trajectory B.
And C, the clamp speeds set at the respective points of interest on the commanded trajectory A are the clamp speeds set at the positions corresponding to the respective points of interest on the commanded trajectories A of the commanded trajectories B and C. It is almost the same value as. Therefore, the moving speeds of the tool 10 on the command trajectory A, the command trajectory B, and the command trajectory C are set to substantially the same value.

As described above, in the trajectory control device 3 according to the first embodiment, in the command program, the same free curve is approximated by a polygonal line formed by connecting different numbers of line segments having different lengths. Even in this case, it is possible to generate a control signal for moving the tool 10 of the machine tool 8 at substantially the same clamping speed, that is, at substantially the same speed, and it is possible to increase the machining accuracy of the machine tool 8.

(3) Second Embodiment (3-1) Features of Trajectory Control Device Hereinafter, a trajectory control device 200 according to a second embodiment will be described. The trajectory control device 200 differs from the trajectory control device 3 according to the first embodiment only in the configuration of the trajectory control unit 20. Hereinafter, the trajectory control unit 20
Will be described only.

The trajectory control unit 20 uses the command trajectory as the original command trajectory, and uses the command trajectory obtained by performing scale space filtering on the original command trajectory as the shape characteristic amount of a free curve for performing linear interpolation. By correcting the command trajectory, by comparing with the shape feature, a minute line segment irrelevant to the direction of the target trajectory included in the command trajectory due to a calculation error of CAD or CAM is deleted. Features. By employing this configuration, the processing accuracy of the machine tool 8 can be improved.

(3-2) Configuration of the trajectory control unit FIG. 10 is a diagram showing each functional block of the trajectory control unit 20. The same functional blocks as those of the trajectory control unit 5 included in the trajectory control device 3 according to Embodiment 1 are denoted by the same reference numerals. The trajectory control unit 20 includes the scale space filtering unit 1
6. Defective line segment removing means 21 and control signal generating means 1
8.

The scale space filtering means 16 performs scale space filtering on the original command trajectory, and outputs the smoothed command trajectory data obtained by the scale space filtering as a free curve shape feature for linear interpolation. The defective line elimination unit 21 compares the command trajectory with the shape feature amount (smoothed command trajectory) output from the scale space filtering unit 16 and selects CAD or CAM of the line segments for performing linear interpolation. The defective line segment caused by the calculation error is removed, and the command trajectory is corrected. The control signal generating means 18 outputs a control signal for driving the servo motor 9 so that the tool 10 of the machine tool 8 moves according to the corrected command trajectory.

(3-3) Control Signal Generation Process FIG. 11 is a flowchart of the control signal generation process executed by the trajectory control unit 20. First, a point of interest is selected (step S21). Scale space filtering is performed using the line segment near the point of interest as the original command trajectory, and the data of the smoothed command trajectory obtained by the scale space filtering is output as the shape feature of the free curve to be linearly interpolated (step S22). . The command trajectory is compared with the shape feature quantity, and a faulty line segment caused by a CAD or CAM calculation error is removed from the line segments for which linear interpolation is performed, and the command trajectory is corrected (step S23). The contents of the process will be described later in detail. A control signal for driving the tool 10 of the machine tool 8 is output according to the corrected command trajectory (step S24). When the processing for all the attention points has been completed (YES in step S25), the processing is completed. On the other hand, if the processing for all the points of interest has not been completed yet (NO in step S25), the next contact point is set as the point of interest to be processed next (step S26), and the process returns to step S22.

FIG. 12 is a flowchart of the defective line segment removal processing (FIG. 11, step S23). First, the inclination of a line segment starting from the point of interest of the original command trajectory is compared with the inclination of a tangent at the point of interest of the smoothed command trajectory (step S31). If the difference between the inclinations is equal to or greater than the predetermined threshold value (YES in step S32), a line segment connecting the contact point immediately before the point of interest and the point of interest among the contact points of the lines constituting the commanded trajectory is selected. A line segment connecting the point and the contact point located immediately after the point of interest, and the contact point immediately after the point of interest and 2
A line segment connecting the succeeding contact point is deleted, an intermediate point of a line segment connecting the deleted point of interest and a contact point located immediately after the point of interest, and one before and two points after the point of interest. After adding two new line segments connecting the located contact points (step S33), the process returns. On the other hand, if the difference between the slope of the line segment starting from the point of interest of the original command trajectory and the slope of the tangent at the point of interest of the smoothed command trajectory is less than the predetermined threshold (NO in step S32) ), Return immediately.

FIG. 13 is a diagram showing an example of execution of the above-described defective line segment removal processing (FIG. 11, step S23) executed by the trajectory control unit 20. FIG. 13A shows a CAD or CAM.
The calculation error, an example of a command trajectory with a line segment extending in the wrong than focused point P ₁ direction. (B) of FIG.
FIG. 9 shows a smoothed command trajectory (shape feature amount) obtained by performing a scale space filter process on the command trajectory (original command trajectory). FIG. (C) in FIG. 13, the line segment connecting the previous contact P ₀ and the noted point P ₁ of the attention point P _1, the contacts located after one of the target point P ₁ and the noted point P ₁ line segment connecting the P _2, and deletes the line segments connecting one contact point P ₂ and the two contact points P ₃ after after attention point P _1, said deleted target point P ₁ and the noticed connecting the contact point P ₀ and P ₃ located behind one before and two intermediate points P _1-2 and the noted point P ₁ of the line segment connecting the contact point P ₂ located after one of the points P ₁ 2 shows the correction of a trajectory for adding two new line segments. FIG. 13D shows the command trajectory after the correction.

As described above, the trajectory control device 200 according to the second embodiment removes a defective line segment caused by a CAD or CAM calculation error from a command trajectory, and removes a defective line from the command trajectory. Processing accuracy is improved, and linear interpolation faithful to a free curve on a design drawing can be performed.

(4) Third Embodiment (4-1) Features of Trajectory Control Device The trajectory control device 300 according to the third embodiment is different from the trajectory control device 3 according to the first embodiment in that a trajectory control unit is provided. 30
Only differ. Hereinafter, only the trajectory control unit 30 will be described.

The trajectory control unit 30 treats the smoothed command trajectory obtained by performing scale space filtering on the original command trajectory as the shape feature of the free curve to be linearly interpolated. It is characterized in that it is replaced with a spline curve based on the feature amount.

By adopting the above configuration, even if the description of the command program for linearly interpolating the same free curve varies, the same spline curve can be attached, and the machine tool 8 connected to the subsequent stage can be attached. Processing accuracy can be improved.

The technique of allocating a spline curve to each line segment for linearly interpolating a free curve is well known, and therefore will not be described here.

(4-2) Configuration of the trajectory control unit FIG. 14 is a diagram showing each functional block of the trajectory control unit 30. The same functional blocks as those of the trajectory control unit 5 included in the trajectory control device 3 according to Embodiment 1 are denoted by the same reference numerals. The trajectory control unit 30 includes the scale space filtering unit 1
6, the control signal generating means 18 and the spline curve calculating means 31.

The scale space filtering means 16 provided in the trajectory control device 3 executes scale space filtering on the original command trajectory, and converts the smoothed command trajectory obtained by performing the scale space filtering into a free curve for linear interpolation. Output as a shape feature. The spline curve calculating means 31 corrects the command trajectory by attaching a spline curve to each line segment based on the calculated shape feature amount. Note that the spline curve to be attached to the line segment is 2
Next-order spline, Third-order spline, Bezier, B-Spline, NU
RBS and the like are conceivable. The control signal generating means 12 outputs a control signal so that the tool 10 moves along the corrected command trajectory.

(4-3) Control Signal Generation Process FIG. 15 is a flowchart of the control signal generation process executed by the trajectory control unit 30. First, a point of interest is selected (step S41). Scale space filtering is performed using the line segment near the point of interest as the original command trajectory, a smoothed command trajectory is obtained, and data representing the obtained waveform is output as a shape feature (step S42). Based on the calculated shape feature, a spline curve is attached to each line segment to correct the command trajectory (step S43). The processing will be described later. A control signal for moving the tool 10 along the corrected command trajectory is output (step S
44). When the processing of all the attention points is completed (YES in step S45), the processing is completed. On the other hand, if the processing for all the points of interest has not been completed yet (NO in step S45), the next contact point is set as the point of interest to be processed next (step S46), and the process returns to step S42.

FIG. 16 shows a spline curve calculation process (FIG. 1).
5 is a flowchart of step S43). The smoothed command trajectory is set as a spline curve that is pasted on a line segment starting from the target point and a line segment starting from the target point (step S50). After the command trajectory is corrected so as to perform spline interpolation using the determined spline curve (step S51), the process returns.

FIG. 17 is a diagram showing an example of a spline curve pasting process executed by the trajectory control unit 30. FIG.
7A shows a part of a command trajectory (original command trajectory) for linearly interpolating a free curve. (B) of FIG. 17 shows a smoothed command trajectory (shape feature amount) obtained by performing the scale spatial filter processing on the original command trajectory. FIG. 17C shows two line segments with the point of interest as a start point and an end point.
The figure which attached the smoothed command locus as a spline curve is shown. (D) of FIG. 17 shows a command trajectory corrected to perform spline interpolation using a spline curve attached to each line segment.

The first row from the top in FIG. 18 shows command trajectories A, B, and C created by the CAM based on the same free curve.
The second row shows the command trajectories A, B, and C that are smoothed by the scale space filtering for the command trajectories A, B, and C. The command trajectories A, B, and C are formed by connecting different numbers of line segments having different lengths. As shown in the figure, the command trajectories A, B, and C smoothed by the scale space filtering all draw substantially the same trajectory. A spline curve is attached to each line segment of the command trajectories A, B, and C based on the shape of the smoothed command trajectories A, B, and C. As a result, as shown in the third row, the same spline curve is attached to each of the command trajectories A, B, and C by the processing, and the command trajectories are corrected to the same command trajectory.

As described above, the trajectory control device 300 according to the third embodiment uses the same spline curve for a free curve expressed by a polygonal line formed by connecting different numbers of line segments having different lengths. Can be installed. Thereby, the same spline interpolation can be performed on the same free curve on the design drawing, and the processing accuracy of the machine tool 8 connected at the subsequent stage can be improved.

(5) Fourth Embodiment (5-1) Features of Trajectory Control Device The trajectory control device 400 according to the fourth embodiment is different from the trajectory control device 3 according to the first embodiment in the trajectory control unit. 40
Only differ. Hereinafter, only the trajectory control unit 40 will be described.

The trajectory control unit 40 is the same as that of the first embodiment,
The trajectory control units 5, 20, and 30 described in 2, 3 have a function provided together. The trajectory commanded by the command program is subjected to scale space filtering, and a smoothed command trajectory obtained by the processing is performed. , The setting of the clamping speed, the removal of the defective line segment, and the attachment of the spline curve are performed.

By employing the above configuration, it is possible to delete a defective line segment generated at the time of creating a command program.
Further, the same spline interpolation can be executed at the point where the same free curve is linearly interpolated based on the movement trajectory after the defective line segment is deleted. Further, the same clamping speed can be set for the same free curve on the design drawing to make the moving speed of the tool 10 the same. Thereby, the processing accuracy of the machine tool 8 connected at the subsequent stage can be improved.

(5-2) Configuration of the trajectory control unit FIG. 19 is a functional block diagram of the trajectory control unit 40 having the above features. The same reference numerals are given to the same functional blocks as those of the trajectory control unit 5 included in the trajectory control devices 3, 200, and 300 according to the first, second, and third embodiments. Trajectory control unit 4
Reference numeral 0 denotes a scale space filtering unit 16, a clamp speed calculating unit 17, a control signal generating unit 18, a defective line segment removing unit 21, and a spline curve calculating unit 31.

The scale space filtering means 16 executes scale space filtering on the original command trajectory, and outputs the smoothed command trajectory obtained by executing the scale space filtering as a shape feature of a free curve for linear interpolation. The clamp speed calculating unit 17 calculates a clamp speed based on the shape feature amount output from the scale space filtering unit 16. Defective line segment removing means 21
Compares the command trajectory with the shape feature quantity output from the scale space filtering means 16 and removes, from the line segments to be subjected to linear interpolation, defective line segments caused by CAD or CAM calculation errors, Modify the trajectory. The spline curve calculating means 31 corrects the command trajectory by attaching a spline curve to each line segment based on the calculated shape feature amount.

(5-3) Control Signal Generation Processing FIG. 20 is a flowchart of the control signal generation processing executed by the trajectory control unit 40. First, a point of interest is selected (step S61). Scale space filtering is performed using the line segment near the point of interest as the original command trajectory to obtain a smoothed command trajectory, and the obtained waveform is output as a shape feature of a free curve for linear interpolation (step S62).

The command trajectory is compared with the shape characteristic amount calculated in step S62 to remove a defective segment caused by a CAD or CAM calculation error from the line segments to be subjected to linear interpolation, thereby correcting the command trajectory. Is performed (step S63). Subsequent processing is performed using the corrected command locus after removing the defective line segment. Note that the content of the process has already been described using the flowchart shown in FIG. 12, and a duplicate description will be omitted here.

Based on the shape characteristic amount calculated in step S62, a spline curve is attached to each line segment for performing linear interpolation, and the command locus is corrected (step S6).
4). Since the content of the process has already been described using the flowchart shown in FIG. 16, the duplicate description will be omitted here.

The clamp speed is calculated based on the shape characteristic amount calculated in step S62 (step S65). Note that the content of the process has already been described using the flowchart shown in FIG. 8, and thus a duplicate description will be omitted here.

The tool 1 is determined based on the command trajectory and the clamp speed corrected in steps S63, S64, and S65.
A control signal for moving 0 is output (step S6).
6). When the processing of all the attention points is completed (step S
If YES at 67), the process ends. On the other hand, if the processing of all the attention points has not been completed yet (N in step S67)
O) After setting the adjacent contact point as the target point to be processed next (step S68), the process returns to step S62.

FIG. 21 shows the smoothed command trajectories A, B, and C obtained when the above-described control signal generation processing is performed on the command trajectories A, B, and C, the defective line removal processing, and the spline curve after pasting. 3 is a diagram showing command trajectories A, B, and C of FIG. The first row from the top in FIG. 21 shows command trajectories A, B, and C created by the CAM based on the same free curve. The command trajectories A, B, and C are composed of a combination of different numbers of minute straight lines having different lengths. The command trajectory C has a line segment α extending in an incorrect direction due to a calculation error of CAD or CAM. In the second row from the top in FIG. 21, smoothed command trajectories A and B obtained by applying scale space filtering to the command trajectories A, B and C are shown.
And C. It can be seen that the command trajectories A, B and C smoothed by the scale space filtering all draw substantially the same trajectory. As shown in the third row from the top in FIG. 21, the command trajectories A and B have no faulty line segments, and thus a spline curve is immediately pasted on each line segment. The command trajectory C is attached with a spline curve after the defective line segment α is removed. Since the shapes of the smoothed command trajectories A, B, and C are substantially the same, the three command trajectories A, B, and C are pasted with spline curves having substantially the same curvature, and as a result, are corrected to substantially the same command trajectory. You. Also, since the shape of the smoothed command trajectory is substantially the same for each trajectory, substantially the same clamping speed is assigned.

As described above, the trajectory control device 400 according to the third embodiment applies the spline curve after correcting the defective line segment included in the command trajectory according to the fourth embodiment. The spline interpolation that is more faithful to the free curve on which the linear interpolation is performed can be performed as compared with. For the same free curve, the moving speed of the tool can be set to be substantially the same. For this reason,
The processing accuracy of the machine tool 8 connected to the subsequent stage can be improved.

(6) Fifth Embodiment (6-1) Features of Trajectory Control Device The trajectory control device 500 according to the fifth embodiment is different from the trajectory control device 100 according to the first embodiment in that a trajectory control unit is provided. 50 are different. Hereinafter, only the trajectory control unit 50 will be described.

The trajectory control unit 50 further detects an edge portion formed by a line segment other than the line segment for linearly interpolating the free curve in the command trajectory, in addition to the trajectory control unit 40 according to the fourth embodiment. When the tool passes through the detected edge portion, a function of reducing the moving speed of the tool according to the angle of the edge is provided so that a large impact does not occur.

By adopting the above configuration, the impact generated when the tool 10 passes through the edge portion is reduced, and the machine tool 8
Processing accuracy can be improved.

(6-2) Configuration of Trajectory Control Unit FIG. 22 is a functional block diagram of the trajectory control unit 50. The same functional blocks as those of the trajectory control unit 40 included in the trajectory control device 400 according to Embodiment 4 are denoted by the same reference numerals. The trajectory control unit 50 includes an edge determination unit 51, an edge processing unit 52, a shape processing unit 53, and a control signal generation unit 1.
8. The edge processing unit 52 includes a tool deceleration amount calculation unit 54. The shape processing unit 53 includes a scale space filtering unit 16, a clamp speed calculating unit 17,
It comprises a defective line segment removing means 21 and a spline curve calculating means 31.

The edge discriminating means 51 determines whether the edge portion in the command locus is an edge portion formed by each line segment for linearly interpolating a free curve, or other than a line segment for linearly interpolating a free curve. It is determined whether the line is an edge formed by the line segment. Specifically, 2
When the length of this line segment is equal to or greater than a predetermined threshold value, it is determined that the edge portion is formed by a line segment other than the line segment for linearly interpolating the free curve. The edge determining unit 51 outputs to the edge processing unit 52 the data of the command trajectory determined to be an edge formed by a line other than the line for linearly interpolating the free curve. On the other hand, the edge determination unit 51 outputs to the shape processing unit 53 the data of the determined command trajectory, which is the edge formed by the line segment for linearly interpolating the free curve.

A command program may be prepared in advance for each line segment to be linearly interpolated, to which data on whether or not the free curve is a line segment to be linearly interpolated is added. In this case, the edge discriminating means 51 performs edge discrimination based on the data added to the input command program.

The tool deceleration calculating means 54 constituting the edge processing section 52 calculates the deceleration of the tool 10 according to the detected angle of the edge, and outputs the calculated deceleration to the control signal generator 18. I do. Note that the deceleration amount is an amount necessary to reduce the moving speed of the tool to an appropriate passing speed of the edge commanded according to the detected angle of the edge.

The command trajectory data, which is not determined by the edge determining means 51 as an edge portion formed by a line segment other than the line segment for linearly interpolating the free curve, is transferred to the scale space filtering means 16 of the shape processing section 53 and the defective line. Minute removal means 2
1 is input. The scale space filtering means 16
Perform scale space filtering on the original command trajectory,
The smoothed command trajectory obtained by performing scale space filtering on the original command trajectory is output as the shape feature of a free curve for linear interpolation. The clamp speed calculating unit 17 calculates a clamp speed based on the shape feature amount output from the scale space filtering unit 16.
The defective line elimination unit 21 compares the command trajectory with the shape feature amount output from the scale space filtering unit 16, and detects a defective line caused by a CAD or CAM calculation error among the line segments for performing linear interpolation. Remove the minute and correct the command trajectory. The spline curve calculation means 31 attaches a spline curve to each line segment based on the calculated shape feature quantity,
Correct the command locus. The control signal generating means 18 includes a deceleration amount output from the tool deceleration amount calculating means 54, data of a command trajectory to which a spline curve is output from the spline curve calculating means 31, and a clamp speed calculating means 1.
Machine tool 8 based on the clamp speed output from
And outputs a control signal of the servo motor 9 provided in the control circuit.

(6-3) Control Signal Generation Process FIG. 23 is a flowchart of the control signal generation process executed by the trajectory control unit 50. First, a point of interest is selected (step S71). Whether the edge portion of the input command trajectory is an edge portion formed by each line segment for linearly interpolating the free curve or an edge portion formed by a line segment other than the line segment for linearly interpolating the free curve. Is determined (step S72). Specifically, when the length of two line segments of the edge portion sandwiching the target point exceeds three times the value of the parameter σ set by the parameter σ setting unit 6 (see FIG. 2), Is determined to be an edge portion. If it is determined that the command trajectory is an edge portion (YES in step S72), the deceleration required to reach a speed at which the tool 10 can pass without generating a large impact based on the angle of the edge portion. The amount is calculated (step S73). An interpolation speed is set based on the calculated deceleration amount of the tool 10 (step S74).

On the other hand, when it is determined that the input command trajectory is not an edge portion formed by a line segment other than the line segment for linearly interpolating the free curve (NO in step S72), the line segment near the target point is set to the original Scale space filtering is performed as the command trajectory to obtain a smoothed command trajectory, and the shape of the obtained smoothed command trajectory is output as a shape characteristic amount of a free curve for performing linear interpolation (step S75).

The command trajectory is compared with the shape characteristic amount calculated in step S75 to remove, from the line segments to be subjected to linear interpolation, a defective line segment caused by a calculation error of CAD or CAM, thereby correcting the command trajectory. Is performed (step S76). Note that the content of the process has already been described using the flowchart shown in FIG. 12, and a duplicate description will be omitted here.

On the basis of the shape characteristic amount calculated in step S75, a spline curve is attached to each line segment to correct the command locus (step S77). Since the content of the process has already been described using the flowchart shown in FIG. 16, the duplicate description will be omitted here.

The clamp speed is calculated based on the shape characteristic amount calculated in step S75 (step S78). Note that the content of the process has already been described using the flowchart shown in FIG. 8, and thus a duplicate description will be omitted here.

A control signal for moving the tool 10 is output based on the command trajectory and the clamp speed corrected in step S74, S76, S77 or S78 (step S79). If the processing of all the points of interest has not been completed yet (NO in step S80), the next contact point is set as the point of interest to be processed next (step S81).
The process returns to step S72. On the other hand, when the processing of all the attention points is completed (YES in step S80), the processing is completed.

As described above, since the trajectory control device 500 according to the fifth embodiment processes the edge portion and the portion of the smooth free curve separately, the processing target including the edge portion and the free curve can be accurately processed. Can be processed well.

[0115]

According to the first trajectory control device of the present invention, the entire trajectory obtained by smoothing discontinuous local changes included in the original command trajectory by the extraction means is recognized as the shape of a free curve for linear interpolation. Then, the movement locus and the movement speed of the tool are adjusted based on the shape. Thereby, even if the description of the command program for linearly interpolating the same free curve varies, the same trajectory and the same moving speed can be assigned.

In the second trajectory control device of the present invention, the entire trajectory obtained by smoothing discontinuous local changes included in the original command trajectory by the extraction means is recognized as a free curve for linear interpolation. Thus, the same trajectory can be set at the point where the same free curve is linearly interpolated by removing the defective line segment generated at the time of creating the command program. This makes it possible to improve the control accuracy of the machine tool connected to the subsequent stage.

The third trajectory control device of the present invention recognizes that the entire trajectory obtained by smoothing discontinuous local changes included in the original command trajectory by the extraction means is a free curve for linear interpolation. Thus, it is possible to execute the same spline interpolation at the point where the same free curve is linearly interpolated. Thereby, the control accuracy of the machine tool connected at the subsequent stage can be improved.

The fourth trajectory control device of the present invention recognizes that the entire trajectory obtained by smoothing discontinuous local changes included in the original command trajectory by the extraction means is a free curve for linear interpolation, The same trajectory can be set at the point where the defective line segment generated at the time of creating the command program is removed and the same free curve is linearly interpolated. Further, after that, the same spline interpolation can be executed at the point where the same free curve is linearly interpolated. Thereby, control accuracy of the machine tool connected at the subsequent stage can be improved.

The fifth trajectory control device of the present invention detects an edge portion formed by a line segment other than a line segment for linearly interpolating a free curve, and determines the moving speed of the tool when passing through the edge portion. By setting according to the angle of the section, more precise speed control of the machine tool connected at the subsequent stage can be realized.

The sixth trajectory control device of the present invention detects an edge portion formed by a line segment having a predetermined length or more as an edge portion formed by a line segment other than a line segment for linearly interpolating a free curve. However, by setting the moving speed of the tool when passing through the edge portion according to the angle of the edge portion, more precise speed control of a machine tool connected to the subsequent stage can be realized.

The seventh trajectory control device of the present invention detects an edge portion formed by a line segment other than a line segment for linearly interpolating a free curve, based on data added to a command program in advance. By setting the moving speed of the tool when passing through the edge portion according to the angle of the edge portion, more precise speed control of a machine tool connected to the subsequent stage can be realized.

The eighth trajectory control device of the present invention recognizes the entire trajectory obtained by smoothing discontinuous local changes included in the original command trajectory by the extraction means as the shape of a free curve for linear interpolation. As a result, the same trajectory and the same moving speed can be assigned to the points where the same free curve is linearly interpolated.

The ninth trajectory control device of the present invention performs more appropriate scale space filtering by setting the value of the parameter σ used in the scale space filter according to the type and size of the tool used in the machine tool. It can be carried out.
As a result, it is possible to assign a more appropriate trajectory and moving speed to a position where the free curve is linearly interpolated.

A tenth trajectory control device according to the present invention provides a trajectory control device which adjusts the accuracy of the movement control of a tool of a machine tool connected to a subsequent stage.
The value of the parameter σ used in the scale space filter is set. As a result, appropriate scale space filtering can be performed, and a more appropriate trajectory and moving speed can be assigned to a portion where the free curve is linearly interpolated.

An eleventh trajectory control device according to the present invention provides a parameter σ according to data of a movement trajectory interval of a tool used in a machine tool, which is input as data for specifying the accuracy of the movement control of the tool of the machine tool. Set. As a result, appropriate scale space filtering can be performed, and a more appropriate trajectory and moving speed can be assigned to a portion where the free curve is linearly interpolated.

The twelfth trajectory control device of the present invention sets a parameter σ in accordance with data of a moving speed of a tool used in a machine tool, which is inputted as data for specifying the accuracy of the movement control of the tool of the machine tool. I do. As a result, appropriate scale space filtering can be performed, and a more appropriate trajectory and moving speed can be assigned to a portion where the free curve is linearly interpolated.

The thirteenth trajectory control device of the present invention sets the parameter σ based on data added to the instruction program in advance. As a result, it is possible to perform an appropriate extraction process of the entire trajectory, and it is possible to assign a more appropriate trajectory and a moving speed to a portion where the free curve is linearly interpolated.

[Brief description of the drawings]

FIG. 1 is a diagram showing an execution example of scale space filtering.

FIG. 2 is a diagram illustrating an example of an N including a trajectory control device according to the first embodiment;
It is a block diagram of C machine tools.

FIG. 3 is a front view of a data input unit.

FIG. 4 is a block diagram of a trajectory control unit.

FIG. 5 is an explanatory diagram of scale space filtering.

FIG. 6 is an explanatory diagram of a data table used in scale space filtering.

FIG. 7 is a flowchart of a control signal generation process.

FIG. 8 is a flowchart of a clamp speed calculation process.

FIG. 9 is a process chart up to calculation of a clamp speed executed by the trajectory control unit.

FIG. 10 is a block diagram of a trajectory control unit according to the second embodiment;

FIG. 11 is a flowchart of a control signal generation process.

FIG. 12 is a flowchart of a defective line segment removal process.

FIG. 13 is an explanatory diagram of a defective line segment removal process.

FIG. 14 is a block diagram of a trajectory control unit according to Embodiment 3.

FIG. 15 is a flowchart of a control signal generation process.

FIG. 16 is a flowchart of a spline curve calculation process.

FIG. 17 is an explanatory diagram of a spline curve calculation process.

FIG. 18 is a diagram illustrating a change in a command trajectory accompanying execution of a control signal generation process.

FIG. 19 is a block diagram of a trajectory control device according to Embodiment 4.

FIG. 20 is a flowchart of a control signal generation process.

FIG. 21 is a diagram illustrating a change in a command trajectory accompanying execution of a control signal generation process.

FIG. 22 is a block diagram of a trajectory control device according to a fifth embodiment.

FIG. 23 is a flowchart of a control signal generation process.

[Explanation of symbols]

1 NC machine tool, 2 program output device, 3, 20
0, 300, 400, 500 trajectory control device, 4 machine tool, 5, 20, 30, 40, 50 trajectory control unit, 16
Scale space filtering means, 17 clamp speed calculating means, 18 control signal generating means, 21 defective line segment removing means, 31 spline curve calculating means, 51 edge discriminating means, 54 corner deceleration speed calculating means

Claims (13)

[Claims] 1. A trajectory control device for outputting a control signal for moving a tool of a machine tool at a trajectory and a speed specified by a command program, wherein the trajectory of the tool specified by the command program is determined by an original command. A trajectory, smoothing discontinuous local changes included in the original command trajectory, and extracting means for extracting the entire trajectory corresponding to the original command trajectory; A trajectory control device comprising: a control unit that performs at least one of correction of the trajectory of the tool and adjustment of the moving speed. 2. The trajectory control device according to claim 1, wherein the control unit differs from a line segment in the movement trajectory by a direction different from the shape of the entire trajectory extracted by the extraction unit by a predetermined angle or more. A trajectory control device comprising: detecting a line segment as a defective line segment; and replacing a nearby line segment including the detected defective line segment with a line segment that follows the shape of the extracted entire trajectory. 3. The trajectory control device according to claim 1, wherein the control unit replaces each line segment in the movement trajectory with a spline curve based on the shape of the entire trajectory extracted by the extraction unit. Trajectory control device characterized. 4. The trajectory control device according to claim 1, wherein the control means has a direction different from the line segment in the movement trajectory by a predetermined angle or more compared to the shape of the entire trajectory extracted by the extraction means. The line segment is detected as a defective line segment, a nearby line segment including the detected defective line segment is replaced with a line segment along the shape of the extracted overall trajectory, and each line segment in the replaced movement trajectory is extracted as described above. A trajectory control device, wherein the trajectory is replaced with a spline curve based on the shape of the entire trajectory. 5. The trajectory control device according to claim 1, further comprising a line segment other than a line segment for linearly interpolating a free curve in a movement trajectory of the tool. Edge detecting means for detecting an edge portion, and speed control means for reducing the moving speed of the tool when passing through the edge portion detected by the edge detecting device in accordance with the angle of the edge portion. Trajectory control device. 6. The trajectory control device according to claim 5, wherein said edge detecting means converts an edge portion formed by a line segment having a predetermined length or more to a line segment other than a line segment for linearly interpolating a free curve. A trajectory control device characterized by detecting an edge portion composed of: 7. The trajectory control device according to claim 1, wherein each of the line segments to be linearly interpolated is data indicating whether or not the line segment is to linearly interpolate a free curve. When a command program to which is added is input, based on the data added to the command program, an edge that specifies an edge portion formed by a line segment other than a line segment that linearly interpolates a free curve. A trajectory control device comprising: a section specifying unit; and a speed control unit configured to reduce a moving speed of a tool passing through the edge specified by the edge unit specifying unit in accordance with an angle of the edge. 8. The trajectory control device according to claim 1, further comprising a parameter σ setting means, wherein said extraction means obtains a movement trajectory of a tool specified by a command program. A trajectory control device which executes a scale space filtering using a Gaussian function having a spread of a parameter σ set by the setting means on the original command trajectory as a command trajectory. 9. The trajectory control device according to claim 8, wherein the parameter σ setting means sets the parameter σ according to the type and size of a tool used in the machine tool. . 10. The trajectory control device according to claim 8, wherein the parameter σ setting means sets the parameter σ in response to input of data specifying the accuracy of the movement control of the tool of the machine tool.
A trajectory control device characterized by setting: 11. The trajectory control device according to claim 10, wherein the parameter σ setting means inputs a movement trajectory of the tool used in the machine tool, which is input as data specifying the accuracy of the movement control of the tool of the machine tool. A trajectory control device characterized in that the parameter σ is set based on the data of the interval. 12. The trajectory control device according to claim 10, wherein the parameter σ setting means inputs the movement speed of the tool used in the machine tool, which is input as data specifying the accuracy of the movement control of the tool of the machine tool. A trajectory control device characterized in that a parameter σ is set based on the data of (1). 13. The trajectory control device according to claim 1, wherein when a command program to which data of a parameter σ used by the extraction unit is added in advance is input, A parameter σ specifying unit that specifies a parameter σ used by the extracting unit based on the data added to the command program, wherein the extracting unit sets a movement locus of the tool commanded by the command program as an original command locus. A trajectory control device for performing scale space filtering using a Gaussian function having the parameter σ extracted by the parameter σ specifying means.