JPH0357422Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control device for a grinding tool, and particularly to an improvement in a device for controlling the pressing force of a grinding tool such as a grindstone against a workpiece.

[Prior Art] Conventionally, devices have been known that attach a grinding tool such as a grindstone to the head of a robot or machine tool and grind a workpiece into a desired shape. Since the amount of grinding of the workpiece changes depending on the amount of grinding, it is necessary to accurately control the pressing force of the grindstone against the workpiece in order to grind the workpiece with high precision.

As such a device, one that controls the weight of the grinding wheel itself that is applied to the workpiece is conventionally known. According to this device, a piston-cylinder type actuator is used to apply a force F' in the direction of lifting the grinding wheel. , based on the following formula, the weight W of the grindstone etc.
The difference between this and the lifting force given by the actuator is set as the pressing force F against the workpiece.

F=W-F′...(1) Therefore, according to this control device, by controlling the magnitude of the force applied by the actuator to lift the grindstone, the pressing force against the grindstone workpiece can be freely recognized. , it becomes possible to grind the workpiece to a desired target grinding amount with high precision.

However, in such a conventional device, when the attitude of the grindstone is fixed constant, the vector component of the self-weight W acting on the workpiece is constant, and good polishing can be performed. When the movement of the workpiece is controlled three-dimensionally along the curved surface of the workpiece, the pressing force F against the workpiece changes due to a change in the vector component of the self-weight W, and the workpiece is ground according to the target grinding amount. There was a problem that it could not be done with high precision.

In order to solve this problem, the applicant has already proposed a device that corrects the lifting force F' of the actuator according to the attitude of the grindstone.

This control device detects the three-dimensional attitude angle A of the grindstone with respect to the vertical direction, and based on this attitude angle A, calculates the following formula so that the pressing force F of the grindstone against the workpiece remains constant regardless of its attitude. The lifting force F′ of the actuator is corrected based on the following.

F'=WCOS A-F... (2) By doing this, even when the grindstone is controlled to move three-dimensionally, it is possible to grind the workpiece with high precision regardless of the posture of the grindstone. It becomes possible.

[Problems to be solved by the invention] However, in such conventional devices, the pressing force F of the grindstone against the workpiece is controlled by adjusting the lifting force F' that acts in the opposite direction to the pressing force F. Therefore, there was a problem in that it was not possible to apply a pressing force F greater than the weight W of the grindstone or the like to the workpiece.

In addition, in such a conventional device, the weight W of the grinding wheel, etc. is used to set the pressing force F, so when the attitude angle A of the grinding wheel is oriented in the vertical direction, the pressing force can be applied over a relatively wide range. However, as the attitude angle A of the grindstone approaches the horizontal angle, the control range of the pressing force gradually becomes smaller, and there is a problem that sufficient grinding work cannot be performed.

In particular, according to this conventional device, the attitude angle A of the grindstone
When the angle exceeds the horizontal angle, the weight of the grinding wheel WCOS A applied to the workpiece becomes O or a negative value, making it impossible to grind the workpiece.

Purpose of the invention The present invention was devised in view of such conventional problems, and its purpose is to satisfactorily control the pressing force over a wide range, regardless of the three-dimensional posture of the grinding tool relative to the workpiece. The object of the present invention is to provide a control device for a grinding tool that can perform the following operations.

[Means for Solving the Problems] In order to achieve the above object, the present invention controls the movement of the grinding tool 22 three-dimensionally along the surface of the workpiece 24, as shown in FIG. Grinding tool 2
2 is pressed against a workpiece 100 according to a predetermined target pressing force F, the grinding tool control device controls the pressing force F' applied to the grinding tool 22 using a piston-cylinder type actuator 20, the target pressing force being applied to the grinding tool 22, A first storage means for storing the force F, a detection means for detecting the attitude angle A of the grinding tool 22 with respect to the workpiece (inclination angle with respect to the vertical direction), and a pressure Pu in the upper cylinder chamber of the actuator and a pressure Pl in the lower cylinder chamber. a second storage means for storing the correspondence between the pressure difference Ps and the pressing force of the actuator on the workpiece, the attitude angle A from the detection means, the target pressing force F from the first storage means, and the weight W of the grinding tool 22.
A first calculating means calculates a corrected target pressing force G according to the posture angle A based on the formula G=FW・COS A, and a second memory stores the corrected target pressing force G calculated by the first calculating means. a second calculating means for calculating the applied pressure to the cylinder upper chamber and the cylinder lower chamber of the actuator from the correspondence relationship stored in the means; and controlling the pressure of the cylinder upper chamber and the lower cylinder chamber of the actuator based on the calculated applied pressure. and pressure control means.

[Function] The present invention has the above configuration, and its function will be explained next.

FIG. 2 shows the relationship between the pressing force F of the inspection tool 22 against the workpiece 24 and the grinding amount of the workpiece 24, and the grinding amount of the workpiece 24 is determined by the grinding amount of the workpiece 24.
Therefore, in order to obtain the target amount of grinding, it is necessary to control the pressing force F of the grinding tool 22 with high precision so that the corresponding target pressing force is obtained.

According to the present invention, the target pressing force of the grinding tool 22 corresponding to the target grinding amount of the workpiece 24 is calculated, the attitude of the grinding tool, that is, the inclination angle with respect to the vertical direction is determined as the attitude angle A, and the attitude angle A No matter what the force is, the actuator 2
The biasing force F' of 0 is controlled.

In particular, according to the present invention, the pressures Pu and Pl applied to the cylinder upper and lower chambers of the actuator 20 are computationally controlled so that the pressing force F thereof becomes the target pressing force, regardless of the attitude angle A of the grinding tool 22. Therefore, the actuator 20 can apply not only a lifting force to the grinding tool 22 but also a pressing force.

As a result, according to the present invention, the pressing force F of the grinding tool 22 is reduced between the grinding tool 22 and the actuator 2.
It is possible to control over a wide range without being limited to the weight of the grinding tool 22.
Even when the attitude angle A of is greater than the horizontal direction, it is possible to perform a good grinding operation using the pressing force F' applied by the actuator 20.

[Example] Next, a preferred example of the present invention will be described based on the drawings.

FIG. 3 shows a preferred embodiment of the present invention, in which a beam member 14 is slidably extended and fixed in the vertical direction to a pair of supports 12 of a processing machine main body 10 formed in a so-called gate shape. This beam material 14
A head 16 is attached and fixed to the head 16 so as to be slidable laterally in the figure.

A piston-cylinder type actuator 20 is attached to the head 16 via an attachment 18 so that its posture can be freely controlled, and a grindstone 22 as a grinding tool is attached and fixed to the tip of the actuator 22. There is. Here, the grindstone 24 is configured to be moved up and down by an actuator 20 and rotated by a motor 21.

Further, below the head 16, a workpiece 24 is provided.
A pallet 26 is provided on which to place the items, and this pallet 26 is movable from front to back in the figure by a moving table 28.

With the above configuration, the relative position of the grindstone 22 with respect to the workpiece 24 can be adjusted between the beam material 14 and the head 1.
6 and a moving table 28, the relative position is controlled three-dimensionally in the X, Y, and Z axis directions, and the attitude angle A of the grindstone 22 with respect to the workpiece 24 is
As a result, the position of the grindstone 22 can be controlled three-dimensionally along the surface of the workpiece 24 along five axes.

FIG. 4 shows an enlarged view of the actuator 20 and grindstone 22, and in the embodiment, the actuator 22 is formed using a piston, a cylinder, and a spring. Here, when considering the pressing force F applied to the workpiece 24 by the grindstone 22,
This pressing force F is expressed by the following equation.

F=W′+F′=WCOS A+F′ However, F′ represents the downward pressing force of the actuator 20, A represents the attitude angle indicating the inclination of the actuator shaft 100 with respect to the vertical direction, and W represents the attitude angle of the actuator 20 and It represents the attachment weight including the grindstone 22.

Here, the pressing force F' applied to the grindstone 22 by the actuator 20 is the differential pressure Ps between the pressure Pu applied to the upper chamber of the cylinder of the actuator 20 and the pressure Pl applied to the lower chamber, that is, Ps=Pu- Given by Pl.

Figure 5 shows this differential pressure Ps and actuator 2.
The relationship with the pressing force F′ of 0 is shown, and from the same figure,
It is understood that the differential pressure Ps and the pressing force F' have a substantially proportional relationship across the dead zone region ΔP.

Therefore, it is understood that by controlling this differential pressure Ps over a wide range from a positive range to a negative range, it is possible to control the pressing force F' applied by the actuator 20 over a wide range from a positive value to a negative value. be done.

FIG. 6 shows a control device 30 of the processing machine, and this control device 30 performs three-dimensional five-axis control of the grindstone 22 and control of the pressing force F' of the actuator 20.

In an embodiment, this controller 30 is a main
CPU32, 1st to 6th axes that calculate and control the 1st to 6th axes
CPU34-1, 34-2, ...34-6, 6 axes
Upper and lower chamber regulator controllers 36-1, 36- operated by commands from the CPU 34-6
2. This regulator controller 36-1, 3
It includes electro-pneumatic regulators 38-1 and 38-2 that convert electrical signals output from 6-2 into pneumatic pressure.

Then, in this control device 30, data for the target pressing force F for obtaining the target grinding amount are inputted to the main CPU 32 via an input unit (not shown) together with data for operating the five axes.

Here, each of these data is set in advance on the floppy disk 40 or the NC tape 42, and the data written on the floppy disk 40 or the NC tape is inputted via the input section. is preferred.

The CPU 32 distributes each data of the 6 axes input in this way, and the 1st to 6th axes CPU 34-1,
34-2, . . . 36-6.

Here, 1 to 5 axis CPU34-1, 34
-2, . . . 34-5 process the data thus input to operate each axis and control the five-axis operation of the machine body.

At the same time, the data on the target pressing force F and the attitude angle A of the welded grindstone 22 calculated by the CPU 32 are sent to the 6-axis CPU 34-6, and the CPU 34-6 uses these data. Based on this, the biasing force F' of the actuator 20 is calculated.

That is, as explained in FIG. 4, the target pressing force is F, the attitude angle of the grindstone 22 is A, and the grindstone 22 is
Assuming that the weight of the actuator 20 is W, the pressing force F' of the actuator 20 is determined by the following equation based on the third equation.

F'=F-WCOS A...(2) And, this 6-axis CPU 34-6
According to the diagram, the pressures Pu and Pl to be applied to the upper and lower chambers of the cylinder of the actuator 20 necessary to generate this pressing force F' are calculated.

Then, the control signals of the applied pressures Pu and Pl obtained in this way are transmitted to the upper chamber regulator controller 26-1 and the lower chamber regulator controller 3.
6-2, and each regulator controller 36-1, 36-2 controls the electro-pneumatic regulator 38-1, 3 according to the input control signal.
Operate 8-2.

By doing this, the actuator 2
Pressures Pu and Pl are applied to the upper and lower chambers of 0, and the actuator 20 generates a pressing force F' corresponding to the difference in thickness Ps.

Therefore, according to the present invention, the grindstone 22 is attached to the workpiece 2.
4. Even if the workpiece 24 moves three-dimensionally along the curved surface and its posture is tilted, the pressing force applied from the grinding wheel 22 to the workpiece 24 is accurately controlled to the target pressing force F, and as a result, the workpiece 24 is moved to the target position. It becomes possible to grind with high accuracy according to the amount of grinding.

In particular, according to the present invention, the pressure Pu applied to the upper and lower chambers of the cylinder of the actuator 20 and
Since Pl is controlled independently, the pressing force of the actuator 20 can be controlled over a wide range of F' from a positive value to a negative value, and as a result, the grinding wheel 2
It becomes possible to control the pressing force against the work 24 of No. 2 to a value greater than the own weight W of the grindstone 22, etc.,
Moreover, even when the attitude angle A of the grindstone 22 is approximately equal to or greater than the horizontal angle, the pressing force F against the workpiece 24 can be well controlled.

On the other hand, in conventional control devices, the pressure Pu applied to the upper chamber of the actuator 20 is kept constant;
Since only the pressure Pl applied to the lower chamber is controlled and the pressing force F' of the actuator is controlled only to a negative value, that is, a lifting force, as in the present invention, the pressing force of the grindstone against the workpiece is Since the value cannot exceed the own weight W of the grinding wheel 22, etc., and furthermore, if the attitude angle A of the grinding wheel 22 exceeds the horizontal angle, pressure cannot be applied to the workpiece. It is not possible to grind a workpiece at a horizontal attitude angle or higher, such as in

As explained above, according to the present invention, compared to conventional control devices, regardless of the attitude of the grindstone 22,
It is understood that the pressing force F of the grindstone 22 against the workpiece 24 can be accurately controlled over a wide range.

Further, according to the present invention, by controlling the pressures Pu and Pl applied to both chambers of the actuator 20 to be high pressures, the pressing force can be controlled with good response.

7 to 9 show other embodiments of a circuit that controls the pressing force F' of the actuator 20 based on the output of the six-axis CPU 34-6.

In the embodiment shown in FIG.
8 is fed back to the regulator controller 36 via the pneumatic regulator 50 to control the applied pressures Pu and Pl to the actuator 20.

In the embodiment shown in FIG. 8, the output of the electro-pneumatic regulator 38 is connected to the electro-pneumatic regulator 5.
0, 6-axis CPU 34- via A/D converter 52
6, input the feedback to actuator 20.
The applied pressures Pu and Pl are controlled.

In the embodiment shown in FIG. 9, a sensor 5 is provided on the actuator 20 to detect the pressing force F'.
4 is provided, and the output of this sensor 54 is sent to a dynamic strain meter 54',
Feedback is input to the 6-axis CPU 34-6 via the A/D converter 52 to control the applied pressures Pu and Pl.

As in the embodiments shown in FIGS. 7 to 9,
By controlling the pressures Pu and Pl applied to the actuator 20 in a feedback manner, it becomes possible to grind the workpiece with higher precision according to the target grinding amount.

[Effects of the invention] As explained above, according to the invention, by independently controlling the pressure applied to the upper and lower chambers of the cylinder of the actuator, the pressing force of the grinding tool against the workpiece can be controlled regardless of its posture. It becomes possible to control with high precision so that the target pressing force is achieved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the configuration of the present invention, Fig. 2 is an explanatory diagram showing the relationship between the pressing force of the grinding tool and the amount of polishing of the workpiece, and Fig. 3 is an explanatory diagram showing a preferred embodiment of the present invention. 4 is a schematic explanatory diagram showing the actuator part of the device shown in FIG. 3, FIG. 5 is a characteristic diagram of the actuator used in this embodiment, and FIG. 6 is a block diagram of the control device used in this embodiment. figure,
7 to 9 are block diagrams showing other embodiments of the present invention. DESCRIPTION OF SYMBOLS 10... Processing machine main body, 18... Attachment, 20... Actuator, 22... Grindstone as a grinding tool, 24... Workpiece, 30... Control device, 32... Main CPU, 34-1 to 34-6
...1st to 6th axis CPU, 36-1...Upper chamber regulator controller, 36-2...Lower chamber regulator controller, 38-1...Upper chamber electropneumatic regulator, 38-2...Lower Room electric pneumatic regulator.

Claims (1)

[Claims for Utility Model Registration] A piston-cylinder type actuator is used to control the movement of a grinding tool three-dimensionally along the surface of a workpiece, and to press the grinding tool against the workpiece according to a predetermined target pressing force. A control device for a grinding tool that controls a pressing force applied to a grinding tool, comprising: a first storage means for storing the target pressing force F; a detection means for detecting an attitude angle A of the grinding tool with respect to the workpiece; Actuator cylinder upper chamber pressure Pu
and second storage means for storing the correspondence relationship between the differential pressure Ps between the pressure Pl and the pressure Pl in the lower cylinder chamber and the pressing force of the actuator against the workpiece, and the attitude angle A from the detection means and the target pressing force from the first storage means. a first calculating means for calculating a corrected target pressing force G according to the attitude angle A using the formula G=FW・COS A based on F and the weight W of the grinding tool; a second calculation means for calculating applied pressures to the cylinder upper chamber and the cylinder lower chamber of the actuator from the target pressing force G and the correspondence stored in the second storage means; A control device for a grinding tool, comprising: pressure control means for controlling pressure in an upper chamber and a lower chamber, and controlling the pressing force to a target pressing force regardless of the control posture of the grinding tool.