JP3399419B2 - Numerical control simulation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical control program simulation device, and in particular, estimates a machining shape of a workpiece when machining is actually executed by a numerically controlled machine tool from a numerical control program and drive system characteristics. The present invention relates to a numerical control program simulation device capable of displaying an estimated machining shape.

[0002]

2. Description of the Related Art In general, a numerical control program and a parameter affecting a machining shape of a work are often checked by a simulation before actually machining with a machine tool. The conventional numerical control simulation device is, for example, "Function and Usage of Cutting Simulation Software-NC-" by Okamura et al. In "Machine and Tool, Vol. 41 No. 2 (1997-2), pp. 46-pp. 50".
Take Verify as an example ”. This first conventional numerical control simulation apparatus will be described with reference to FIG.

Reference numeral 1 is a program reading section for reading in a numerical control program, 2 is a pre-processing section for performing pre-processing such as shape correction using correction parameters in the read numerical control program, and 5a is corrected by the pre-processing section. A 3D solid simulation unit that calculates a 3D solid model of the work using the path and the material shape of the work, and 6a is a shape display unit that displays the 3D solid model.

The shape correction is, for example, a tool diameter correction, a tool length correction, a process of converting a minute line segment into a spline curve, and the like. The correction parameter is, for example, a tool radius correction amount,
Tool length correction amount, tolerance (distance between minute line segment and spline curve), and the like. The material shape defines the shape of a workpiece (such as a rectangular parallelepiped) before cutting.
As described above, by calculating and displaying the 3D solid model from the numerical control program, it is possible to know the machining shape of the workpiece close to when the numerical control program is executed without actually performing the machining. Further, by developing this simulation device, a load calculating unit 14a and a feed rate calculating unit 15a are added, and the load when cutting the work is calculated from the result of simulating the numerical control program so that the load is optimized. There is also a simulation device that creates a numerical control program with the feed rate corrected.

A second conventional numerical control simulation apparatus is described in, for example, Japanese Patent Laid-Open No. 3-095605. A second conventional numerical control simulation device will be described with reference to FIG. Since 1 and 2 are the same as the first conventional example, the description thereof will be omitted. 3 is an interpolation / acceleration / deceleration unit that performs interpolation / acceleration / deceleration using the path and acceleration / deceleration parameters corrected by the preprocessing unit, and 4 is a servo parameter that takes drive system characteristics into consideration for the result of interpolation / acceleration / deceleration. A drive system model for estimating the tool tip position using the reference numeral 21 is a display unit for displaying together the tool tip trajectory in the simulation and the command path by the numerical control program.

Here, the drive system is composed of elements such as a servo, a motor, and a machine, and indicates the relationship between the position of the tool tip and the position where interpolation / acceleration / deceleration is performed. The acceleration / deceleration parameters include an acceleration / deceleration time constant, a corner deceleration angle (a parameter for setting a threshold value of an angle that requires deceleration), an accuracy coefficient, and the like. The servo parameters are position loop gain, feedforward gain, and the like. From the above, it is possible to perform a simulation of the tool path including the drive system characteristics of the machine tool, and to compare the simulation result of the tool path including the drive system characteristics and the route instructed by the numerical control program. .

A third conventional numerical control simulation apparatus is described in, for example, Japanese Patent Application Laid-Open No. 4-302306 and Japanese Patent Application Laid-Open No. 10-76444. A third conventional numerical control simulation apparatus will be described with reference to FIG. Since the items 1 to 3 are the same as those of the first and second conventional techniques, description thereof will be omitted. Reference numeral 4b is a servo amplifier that receives a command and drives a motor, 22 is a data measuring unit that measures the state quantity of the servo amplifier, and 23 is an automatic adjustment control unit that calculates sampling data and changes / controls it to desired parameters. . As described above, the parameters such as the feedforward gain and the acceleration / deceleration filter can be automatically tuned to the optimum values, and the cost for adjusting the optimum parameter values can be reduced.

[0008]

The conventional numerical control simulation apparatus is configured as described above, and the first conventional numerical control simulation apparatus does not consider interpolation / acceleration / deceleration and drive system characteristics. , Only the machining shape based on the trajectory drawn by the numerical control program is displayed, and the trajectory drawn by the numerical control program and the actual movement of the tool tip when machining the workpiece are different, so the numerical control machine tool is actually The machining shape of the work when machining is executed is not displayed.

Therefore, even if there is no problem in the simulation, a defective product may be produced when the work is actually cut, and the simulation cannot judge whether the work is good or bad. As a result, production efficiency deteriorates and costs also increase. Also, regarding the simulation device that creates a numerical control program that modifies the feed rate so that the load when cutting the work is optimal, interpolation / acceleration / deceleration and drive system characteristics are not taken into consideration. The load on the work when cutting is different from the load on the work obtained as a result of simulation, and it cannot be said that the optimum feed rate for actually cutting the work is found.

Further, in the second conventional numerical control simulation apparatus, the result of the simulation including the drive system characteristics of the machine tool is the tool path and not the 3D solid model. Therefore, when the operator executes the numerical control program. It is difficult to recognize the processed shape of the work. Therefore, it is not possible to judge whether the work is good or bad. As a result, production efficiency deteriorates and costs also increase. Moreover, the parameters used for the simulation cannot be adjusted from the simulation result.

Further, in the third conventional numerical control simulation apparatus, the numerical control apparatus actually issues a command to the servo amplifier to operate the motor and samples feedback data to perform automatic tuning of parameters. , The parameters cannot be adjusted without actually operating the machine tool. It takes time to actually operate the machine tool, and the operating rate of the machine is reduced.

The present invention has been made to solve the above-mentioned problems, and based on the numerical control program and the characteristics of the drive system, the machining shape of the work when the machining is actually executed by the numerically controlled machine tool is performed. An object of the present invention is to provide a numerical control simulation device capable of estimating and displaying an estimated machining shape.

Further, an object of the present invention is to provide a numerical control simulation apparatus capable of reducing the shape error by searching for the optimum value of the parameter affecting the machining shape of the workpiece from the difference between the estimated machining shape and the target machining shape. Is.

Further, another object of the present invention is to provide a numerical control simulation device capable of correcting the path and the feed rate commanded to the numerical control program to the optimum ones based on the difference between the estimated machining shape and the target machining shape.

[0015]

A numerical control simulation apparatus according to the present invention corrects the read command path by using a program reading section for reading a numerical control program for commanding a work machining path, and a correction parameter. A pre-processing unit that obtains a corrected route, an interpolation / acceleration / deceleration unit that performs interpolation / acceleration / deceleration based on the corrected route and acceleration / deceleration parameters, and servo parameters are used for the results of interpolation / acceleration / deceleration. 3D for calculating an estimated machining shape by performing a 3D solid simulation using the drive system model for estimating the tool tip position by using the tool tip position
A solid simulation unit, a shape display unit that displays the calculated estimated machining shape, and a shape error calculation unit that compares the target machining shape and the estimated machining shape and calculates the shape error data. Accordingly, the display attribute of each part of the estimated processed shape is changed and displayed on the shape display portion.

[0016]

[0017]

[0018]

Further, the apparatus is provided with a parameter change plan formulation section for formulating a plan for modifying the parameters affecting the machining shape of the workpiece based on the shape error data.

The parameter change is made in consideration of the vibration of the tool tip position.

A numerical control simulation apparatus according to the present invention reads a numerical control program for instructing a work machining path, and a correction parameter to correct the read command path to obtain a corrected path. A pre-processing unit, an interpolation / acceleration / deceleration unit that performs interpolation / acceleration / deceleration based on the corrected path and acceleration / deceleration parameters, and a tool tip position is estimated using servo parameters for the result of interpolation / acceleration / deceleration. 3D solid simulation unit that performs a 3D solid simulation using the drive system model and the tool tip position to calculate an estimated machining shape, a shape display unit that displays the calculated estimated machining shape, and a target machining shape Calculated by the shape error calculation unit that compares the processed shapes and calculates the shape error data, and the shape error calculation unit A path characteristic analysis section shape error to analyze the characteristics of the path of the portion present which is obtained by a route feature display unit for displaying the characteristics of the analyzed path.

[0022]

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. Embodiment 1. 1 is a block diagram showing a numerical control simulation apparatus according to a first embodiment of the present invention. 1
Is a program reading unit that reads a numerical control program, 2 is a preprocessing unit that performs preprocessing such as shape correction on the read program, and 3 is interpolation / acceleration / deceleration that performs interpolation / acceleration / deceleration based on the preprocessed result It is a department. Reference numeral 4 denotes a drive system model for estimating the tool tip position in consideration of the drive system characteristics with respect to the result of interpolation / acceleration / deceleration, which is disclosed in, for example, Japanese Patent Laid-Open No. 3-095605. Further, 5 is a 3D solid simulation unit for calculating an estimated machining shape by performing 3D solid simulation using the tool tip position, and 6 is a shape display unit for displaying the estimated machining shape.

In the numerical control simulation apparatus configured as described above, the 3D solid simulation section 5 calculates the estimated machining shape based on the tool tip position estimated in consideration of the drive system characteristics. The shape is closer to the machining shape when the workpiece is actually machined by the machine tool, as compared with the 3D solid model shown in the first conventional technique. In addition, by displaying the estimated machining shape on the estimated shape display unit 6, before machining the workpiece by the machine tool, the machining shape close to that when the workpiece is actually machined by the machine tool is displayed. Therefore,
It is possible to judge whether the work is good or bad on the simulation, and as a result, the production efficiency can be increased and the cost can be reduced.

Embodiment 2. 2 is a block diagram showing a numerical control simulation apparatus according to a second embodiment of the present invention. Since 1 to 6 are the same as those shown in the first embodiment, description thereof will be omitted. 7 is a shape error calculation unit that compares the target machining shape with the estimated machining shape,
Reference numeral 8 denotes a shape error display unit that changes and displays the display attribute of each part of the estimated processed shape when it is displayed on the shape display unit according to the size of the shape error.

FIG. 3 shows an example in which the target machining shape and the shape error data are superimposed and displayed on the shape error display section 7. You can see at a glance where there is an error between the estimated machining shape and the target machining shape. Further, by using light and shade as the display attribute, it is possible to see at a glance how the magnitude of the shape error changes. It goes without saying that other display attributes such as color and fill pattern can be used. Further, since the boundary where the display attribute changes can be defined by a numerical value, it is possible to see at a glance how large the shape error is. This definition can be made by the shape error display parameter and can be set by the operator. Here, the target machining shape is a shape designed by CAD or the like. As described above, from the difference between the estimated machining shape and the target machining shape, the optimum value of the parameter affecting the machining shape of the work can be searched for, and the shape error can be reduced.

Embodiment 3. FIG. 4 is a block diagram showing a numerical control simulation apparatus according to the third embodiment of the present invention. Since 1 to 8 are the same as those shown in the second embodiment, description thereof will be omitted. Reference numeral 9 is a route feature analysis unit that identifies a block route corresponding to a portion having a large shape error and analyzes the features of the route, and 10 is a route feature display unit that displays the route features.

In order to realize the path feature analysis unit 9, first, using the shape error data (error map) and the estimated machining shape (Z coordinate map), the shape error occurs in which block of the numerical control program. Must be identified. Therefore, when the estimated machining shape is created in the 3D solid simulation unit 5, the cutting at this position on the estimated machining shape is performed by the command of this block of the numerical control program (block number map). ).

When displaying the route feature on the route feature display unit 10, it is better to display the route locus of the tool tip position obtained by the drive system model 4 as well because the error of the route can be seen at a glance.

FIG. 5 shows an example in which the trajectory of the commanded route and the trajectory of the tool tip position are superimposed and displayed on the route feature display unit 10. The trajectory of the command path is the linear length of one block command,
By displaying the information of the angle formed by the straight line command of the next block together, it is possible to estimate the cause of the shape error in which block. For example, in the example shown in the figure, it can be seen at a glance that the angles formed by the minute line segments are all smaller than the corner deceleration angle, and therefore the operator can presume that a shape error has occurred without corner deceleration. When the command is not a minute line segment as in the example of the drawing, for example, in the case of an arc command, it is effective to display the radius information.

Fourth Embodiment FIG. 6 is a block diagram showing a numerical control simulation apparatus according to the fourth embodiment of the present invention. Since 1 to 8 are the same as those shown in the second or third embodiment, the description thereof will be omitted. Reference numeral 11 is a parameter change plan formulation unit that formulates a plan for modifying parameters.

When the parameter change plan formulation unit 11 formulates the parameter change plan based on the shape error data from the shape error calculation unit 7 in the second embodiment, the range in which the locus of the tool tip position does not become oscillatory. In the following, we propose a method of increasing the gain of the servo parameter so that the shape error is reduced. The operator will confirm the proposed plan before using it for the next processing.

FIG. 7 is a flow chart for obtaining optimum values of parameters such as position loop gain and feedforward gain. Step 1: The operator sets the allowable amount of shape error. step 2: A simulation is performed. Step 3: Based on the information from the drive system model 4, it is determined whether or not it is oscillating. When it is determined that the vibration is vibrating in step 4: step 3, the parameter amount is lowered until it is not vibrating. Step 5: The shape error calculation unit 7 obtains the shape error amount of the shape error existing portion. Step 6: It is determined whether the shape error amount is smaller than the allowable shape error amount. If it is small, it ends, and if it is large, ste
Go to p7. Step 7: Increase the parameter amount by the parameter change amount. Step 8: Perform simulation. Step 9: Based on the information from the drive system model 4, it is determined whether or not it is oscillating. If it is vibrating, ste
Proceed to p12, and if not oscillatory, proceed to step10.

Step 10: By the shape error calculation unit 7,
The amount of shape error of the part where the shape error exists is calculated. Step 11: Compare the shape error amounts of the previous time and this time, and if the shape error amount has decreased, proceed to Step 13, and if not, proceed to Step 12. Step 12: If it is determined to be oscillating in Step 9, or if the shape error amount has increased in Step 11 from the previous time, the parameter amount is returned to the original value, the parameter change amount is halved, and the process returns to Step 7. Step 13: It is determined whether the shape error amount is smaller than the allowable shape error amount. If it is small, end, if it is large, st
Return to ep7. Alternatively, the shape error amounts of the previous time and this time are compared, and if they are almost the same, it is determined that it is impossible to reduce the shape error by increasing the parameter amount, and the process ends.
Return to ep7.

Further, when the parameter change plan formulation unit 11 formulates the parameter change plan based on the route feature data from the route feature analysis unit 9 in the third embodiment,
In the case of the minute line segment command as shown in FIG. 5, a plan to change the corner deceleration angle is presented. The operator will confirm the proposed plan before using it for the next processing.

FIG. 8 is a flowchart for obtaining the optimum corner deceleration angle. Step 21: The operator sets the allowable amount of shape error. Step 22: The shape error calculation unit 7 obtains the shape error amount of the shape error existing portion. Step 23: It is determined whether the shape error amount is smaller than the allowable shape error amount. If it is small, end, if it is large, st
Go to ep24. Step 24: The route feature analysis unit 9 obtains the feature of the route of the portion where the shape error exists. Step 25: It is judged whether or not the cause of the shape error is that the angle formed by the linear command is smaller than the corner deceleration angle and deceleration has not been achieved at the place where deceleration is required. If so, proceed to Step 26, and if not Is ste
Go to p29.

Step 26: As a result of the determination in Step 25, the corner deceleration angle is set again to reduce the shape error. Step 27: Calculate the shape error with a new corner deceleration angle. Step 28: It is judged whether or not the shape error amount becomes smaller than the allowable shape error amount by decreasing the corner deceleration angle. If the shape error amount becomes smaller, the process ends, and if not, the process proceeds to Step 29. Step 29: Since it is determined that the shape error amount cannot be reduced by changing the corner deceleration angle, the accuracy coefficient is adjusted.

In the condition of step 25, the cause of the shape error may be that the angle formed by the straight line command is larger than the corner deceleration angle and the vehicle is decelerating at a place where deceleration is not necessary. In that case, ste
This can be dealt with by increasing the corner deceleration angle at p26.

Embodiment 5. FIG. 9 is a block diagram showing a numerical control simulation apparatus according to the fifth embodiment of the present invention. Since 1 to 8 are the same as those shown in the second embodiment, description thereof will be omitted. Reference numeral 13 is a target machining shape creation unit that creates a target machining shape from the path designated by the numerical control program by 3D solid simulation.

The target machining shape forming section 13 is the same as that of the second embodiment.
Then, the target machining shape need not be prepared by calculating from the numerical control program itself the target machining shape that had to be prepared separately from the numerical control program.

Sixth Embodiment FIG. 10 is a block diagram showing a numerical control simulation apparatus according to the sixth embodiment of the present invention. Since 1 to 6 are the same as those shown in the first embodiment, description thereof will be omitted. Reference numeral 14 is a load calculation unit for calculating the load from the estimated machining shape, and 15 is for correcting the feed rate so that the calculated load becomes constant or fast-feed when cutting is not actually performed. It is a feed rate calculation unit. Here, the load is, for example, cutting torque.

The feed rate corrected by the feed rate calculator 15 is written in the numerical control program. Estimated machining shape by numerical control program with corrected feed rate,
Since the estimated machining shape by the numerical control program before being modified is different, the modified numerical control program is further read by the program reading unit 1 to perform a simulation based on the drive system characteristics. If there is no modification to the created numerical control program, it means that the numerical control program described with the optimum feed rate is created.

[0043]

As described above, according to the present invention, a program reading section for reading a numerical control program for instructing a work machining path, and a correction parameter are used to correct the read command path, and a corrected path is obtained. A preprocessing unit to be obtained, an interpolation / acceleration / deceleration unit that performs interpolation / acceleration / deceleration based on the corrected path and acceleration / deceleration parameters,
A drive system model for estimating a tool tip position using a servo parameter for a result of acceleration / deceleration, and a 3D solid simulation unit for performing an 3D solid simulation using the tool tip position to calculate an estimated machining shape,
A shape display unit that displays the calculated estimated machining shape,
The target machining shape and the estimated machining shape are compared with each other, and a shape error calculating unit that calculates the shape error data is provided. By changing and displaying, the operator can visually confirm the ratio of the error of the site where the error exists.

[0044]

[0045]

[0046]

Further, by providing the parameter change plan formulating section for formulating a plan for changing the parameter affecting the machining shape of the work based on the shape error data, the information of the specified location having a large shape error can be used. It is possible to search for the optimum value of the parameter that also affects the machining shape and automatically set the parameter and reduce the shape error. Alternatively, by presenting to the operator the recommended value of the parameter that improves the accuracy of the work shape of the work, it is possible to help the operator to set the parameter that affects the work shape of the work, and reduce the shape error. You can

Further, by changing the parameter in consideration of the vibration of the tool tip position, the gain of the servo parameter can be increased and the shape error can be reduced within the range where the trajectory of the tool tip position does not become oscillatory. .

According to the present invention, a program reading section for reading a numerical control program for instructing a workpiece machining path, a preprocessing section for correcting the read command path by using a correction parameter, and obtaining a corrected path. , Interpolation based on the corrected path and acceleration / deceleration parameters
An interpolation / acceleration / deceleration unit that performs acceleration / deceleration, a drive system model that estimates the tool tip position using servo parameters for the result of interpolation / acceleration / deceleration, and 3D using the tool tip position.
A 3D solid simulation unit that performs a solid simulation to calculate an estimated machining shape, a shape display unit that displays the calculated estimated machining shape, and a shape error that compares the target machining shape and the estimated machining shape and calculates shape error data. A calculation unit, a route characteristic analysis unit that analyzes the characteristic of the route of the portion where the shape error calculated by the shape error calculation unit exists, and a route characteristic display unit that displays the analyzed characteristic of the route. As a result, the operator can assist in estimating what causes the location where the shape error is large.

[0050]

[Brief description of drawings]

FIG. 1 is a block diagram showing a numerical control simulation device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a numerical control simulation device according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram in which a target machining shape and shape error data are displayed in an overlapping manner on a shape error display unit 7 of the numerical control simulation apparatus of FIG.

FIG. 4 is a block diagram showing a numerical control simulation apparatus according to a third embodiment of the present invention.

5 is an explanatory diagram in which a trajectory of a command route and a trajectory of a tool tip position are displayed in an overlapping manner on the route feature display unit 10 of the numerical control simulation apparatus of FIG.

FIG. 6 is a block diagram showing a numerical control simulation device according to a fourth embodiment of the present invention.

7 is a flowchart for obtaining optimum values of parameters such as position loop gain and feedforward gain in the numerical control simulation apparatus of FIG.

8 is a flow chart for obtaining an optimum corner deceleration angle in the numerical control simulation apparatus of FIG.

FIG. 9 is a block diagram showing a numerical control simulation device according to a fifth embodiment of the present invention.

FIG. 10 is a block diagram showing a numerical control simulation device according to a sixth embodiment of the present invention.

FIG. 11 is a block diagram showing a first conventional numerical control simulation apparatus.

FIG. 12 is a block diagram showing a second conventional numerical control simulation apparatus.

FIG. 13 is a block diagram showing a third conventional numerical control simulation apparatus.

[Explanation of symbols]

1 program reading part, 2 preprocessing part, 3 interpolation
Acceleration / deceleration section, 4 drive system model, 4b servo amplifier,
5, 5a 3D solid simulation unit, 6 estimated shape display unit, 6a 3D solid display unit, 7 shape error calculation unit, 8 shape error display unit, 9 path feature analysis unit, 1
0 route feature display section, 11 parameter change plan development section, 1
3 target machining shape creation unit, 14, 14a load calculation unit,
15, 15a Feed rate calculation unit, 21 Display unit, 22
Data measurement unit, 23 automatic adjustment control unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G05B 19/18-19/46 B23Q 15/00-15/28

Claims (4)

(57) [Claims] 1. A program reading section for reading a numerical control program for instructing a workpiece machining path, a preprocessing section for correcting the read instructed path by using a correction parameter, and obtaining a corrected path, the correction section. An interpolation / acceleration / deceleration unit that performs interpolation / acceleration / deceleration based on the route and acceleration / deceleration parameters, a drive system model that estimates the tool tip position using servo parameters for the results of interpolation / acceleration / deceleration, A 3D solid simulation section that performs a 3D solid simulation using the tip position to calculate an estimated machining shape, a shape display section that displays the calculated estimated machining shape, a target machining shape and an estimated machining shape are compared, and a shape error is calculated. And a shape error calculation unit for calculating, and each of the estimated processed shape when displaying on the shape display unit according to the shape error data. A numerical control simulation device characterized in that the display attribute of a part is changed and displayed. 2. The method according to claim 1, further comprising a parameter change plan formulation unit that formulates a plan for modifying a parameter that affects a machining shape of a workpiece based on shape error data.
Numerical control simulation device described. 3. The numerical control simulation apparatus according to claim 2, wherein the parameter change is performed in consideration of the vibration of the tool tip position. 4. A program reading section for reading a numerical control program for instructing a workpiece machining path, a preprocessing section for correcting the read command path by using a correction parameter, and obtaining a corrected path, the correction section. An interpolation / acceleration / deceleration unit that performs interpolation / acceleration / deceleration based on the route and acceleration / deceleration parameters, a drive system model that estimates the tool tip position using servo parameters for the results of interpolation / acceleration / deceleration, A 3D solid simulation section that performs a 3D solid simulation using the tip position to calculate an estimated machining shape, a shape display section that displays the calculated estimated machining shape, a target machining shape and an estimated machining shape are compared, and a shape error is calculated. And a shape error calculation unit that calculates the A numerical control simulation device, comprising: a route feature analysis unit that performs the above; and a route feature display unit that displays the analyzed feature of the route.