KR102065861B1 - Measuring method of on-machine measurement equipment - Google Patents

Abstract

Disclosed is a measuring method of an on-machine measuring apparatus. According to the present invention, the disclosed measuring method of the on-machine measuring apparatus, in a measuring method of an on-machine measuring apparatus which is able to be mounted on a spindle of a processing machine to measure the shape of a workpiece, comprises: a step (300) of compensating a constraint motion to calculate a subordinate angle change volume of the on-machine measuring apparatus generated due to a constraint motion in the axial direction of the spindle; a step (310) of measuring an offset error of the on-machine measuring apparatus to measure the degree of deviation of the center of an end unit of the on-machine measuring apparatus from the axis of the spindle while keeping a status of rotating the spindle in the reverse direction as much as the subordinate angle change volume; and a step (320) of measuring a workpiece to measure the shape of the workpiece while keeping the status of rotating the spindle in the reverse direction as much as the subordinate angle change volume, and reflect the offset error measured in the step (310) of measuring the offset error, thereby calculating precise dimensions of the workpiece. According to the present invention, the measuring method of the on-machine measuring apparatus measures the shape of the workpiece by reflecting the subordinate angle change volume reflected in the on-machine measuring apparatus due to a constraint motion of the processing machine.

Description

Measuring method of on-machine measurement equipment

The present invention relates to a method for measuring a meteorological measuring device, and more particularly, to calculate the dependent angle change of the meteorological measuring device generated by the restraint motion of a processing machine including a parallel mechanism, to measure the offset error and the workpiece of the meteorological measuring device. By reflecting in the measurement, the present invention relates to a measuring method of a meteorological measuring device that enables the accurate shape of a workpiece to be measured.

As the field of application of multi-axis processing machines, such as robots and machine tools, is diversified, machines adopting a parallel or serial / parallel hybrid structure rather than a general series structure are being developed, and some structures have been released for processing.

The parallel mechanism has the advantage that the moving mass is distributed to each actuator to enable agile driving and to take a flexible tool posture.

Exechon's The Parallel Kinematic Machine (PKM) is a successful commercially available form of parallel and hybrid machine tools. Neumann has developed a structure that replaces ball joints in a tricept structure, ensuring sufficient rigidity and precision for machining. . In addition, since there are all degrees of freedom for relative movement on the tool side, it is utilized for machining large parts such as aircraft wings in connection with expansion axes such as gantry systems.

On-machine measurement equipment is a device that is mounted on a processing machine to measure and has the advantage of reducing production costs and time by integrating processing and inspection.

Recently, a meteorological measuring device is also used to measure errors of a machine tool and a 3D measuring device by using a measuring probe and a measuring verification master.

As a sensor used for meteorological measurement, a touch-trigger probe, a scanning probe, and a laser displacement sensor are used. In particular, the touch probe is relatively inexpensive and easy to maintain, and thus is widely used for industrial purposes.

In the processing machine including the parallel mechanism introduced above, the spindle is subject to a dependent angle change due to the restraining movement in the spindle axis direction. This also has a great influence on the meteorological measuring device mounted on the spindle to perform the measurement.

For this reason, in the meteorological measuring device mounted on the machining machine that performs the restraint motion, the dependent angle change due to the restraint motion during the measurement is reflected in the measured value, thereby preventing accurate measurement.

Therefore, there is an urgent need to develop a new measuring method to compensate for the measurement error caused by the restraining motion when measuring the shape of a workpiece with a meteorological measuring device mounted on a processing machine accompanied with restraint motion.

Korean Patent Publication No. 10-1099687

The present invention has been proposed to solve the above problems, and an object of the present invention is to compensate the dependent angle change generated due to the restraint motion of a machining machine during workpiece measurement.

In addition, an object of the present invention is to compensate the dependent angular change caused by the restraint movement of the processing machine when the offset error measurement.

 The present invention is a measuring method of a meteorological measuring device mounted on a spindle of a processing machine to measure the shape of a workpiece,

A restraining motion compensating step of calculating a dependent angle change amount of the meteorological measuring device generated due to the restraining motion in the spindle axis direction;

An offset error measurement step of measuring a degree of deviation of the center of the end of the weather measuring device from the spindle axis while maintaining the state in which the spindle is rotated in the reverse direction by the dependent angle change amount;

A workpiece measurement step of calculating the exact dimensions of the workpiece by measuring the shape of the workpiece while maintaining the state in which the spindle is rotated in the reverse direction by the dependent angle change amount, and reflecting the offset error measured in the offset error measurement step; ,

The present invention provides a measuring method for a meteorological measuring device, characterized in that for measuring the shape of a workpiece by reflecting a dependent angle change amount reflected in the meteorological measuring device due to the restraining motion of the processing machine.

In addition, the meteorological measuring device is characterized in that the touch probe (Touch-trigger probe).

In addition, the offset error measuring step is characterized in that for measuring the degree of deviation of the stylus ball center of the touch probe end mounted on the spindle with respect to the spindle axis of the machining machine.

In addition, the meteorological measuring device is characterized in that the scanning probe (Scanning probe).

In addition, the meteorological measuring device is characterized in that the laser scanner (Laser Scanner).

In addition, the restraint motion compensating step is characterized by calculating the dependent angle change amount of the meteorological measuring device generated by the restraint motion of the spindle through the kinematic calculation at the measurement position.

In addition, the offset error measuring step,

After measuring the machine coordinates by touching the touch probe to the four points of the inner diameter of the circular master where the two straight lines crossing the circular master contact the circular master, the x-axis direction of the two points ( p ₁ , p ₃ ) where the first straight line is in contact The coordinates are averaged and the y-direction coordinates of the two points ( p ₂ , p ₄₎ contacted by the second straight line are averaged so that the x-axis center coordinates ((x1 + x3) / 2) and the y-direction center coordinates ((y2) of the circular master are averaged. + y4) / 2 ₎ , where x1 is the x-direction coordinate of p ₁ , x3 is the x-direction coordinate of p ₃ , y2 is the y-direction coordinate of p ₂ , and y4 is the y-direction coordinate of p ₄ being)

Move the touch probe to the point ( p ₅ ) corresponding to the calculated x-axis center coordinate ((x1 + x3) / 2) and y-axis center coordinate ((y2 + y4) / 2 ₎ of the circular master,

Rotate the touch probe 180 degrees,

The touch probe is moved from the point ( p ₅ ) corresponding to the center coordinates of the circular master in the x direction to measure the mechanical coordinates of the contact point ( p ₆ ) and the contact point ( p ₇ ) in the y direction.

Equation

Where o _{x , p} and o _{y , p} are offset errors in the x and y directions of the touch probe, R _master and r _stylus are the radius of the circular master and stylus balls, x5 is the x coordinate of p 5 , x6 is the x-coordinate of p6 , y5 is the y-coordinate of p 5, y7 is the y coordinate of p7 ), and the offset error of the circular master is measured.

In addition, the offset error measuring step,

Measure the machine coordinates by touching the touch probe to the four points of the outer diameter of the circular master where the two straight lines across the circular master contact the circular master.Then, the x-axis direction of the two points ( p ₁ , p ₃ ) where the first straight line is in contact The coordinates are averaged and the y-direction coordinates of the two points ( p ₂ , p ₄₎ contacted by the second straight line are averaged so that the x-axis center coordinates ((x1 + x3) / 2) and the y-direction center coordinates ((y2) of the circular master are averaged. + y4) / 2 ₎ , where x1 is the x-direction coordinate of p ₁ , x3 is the x-direction coordinate of p ₃ , y2 is the y-direction coordinate of p ₂ , and y4 is the y-direction coordinate of p ₄ being)

Move the touch probe to the point ( p ₅ ) corresponding to the calculated x-axis center coordinate ((x1 + x3) / 2) and y-axis center coordinate ((y2 + y4) / 2 ₎ of the circular master,

Rotate the touch probe 180 degrees,

The touch probe is moved from the point ( p ₅ ) corresponding to the center coordinates of the circular master in the x direction to measure the mechanical coordinates of the contact point ( p ₆ ) and the contact point ( p ₇ ) in the y direction.

Equation

Where o _{x , p} and o _{y , p} are offset errors in the x and y directions of the touch probe, R _master and r _stylus are the radius of the circular master and stylus balls, x5 is the x coordinate of p 5 , x6 is the x-coordinate of p6 , y5 is the y-coordinate of p 5, y7 is the y coordinate of p7 ), and the offset error of the circular master is measured.

In the present invention, the dependent angle change amount may be reflected in the offset of the touch probe in the machining machine accompanied with the restraint motion, thereby increasing the measurement accuracy.

In addition, the present invention has the effect that can be applied to various types of meteorological measuring device as well as touch probe.

In addition to the effects described above, the specific effects of the present invention will be described together with the following description of specifics for carrying out the invention.

1 is a perspective view of a parallel machine processing machine of Exechon.
Figure 2 is a view showing the degree of freedom and coordinate system for the parallel machine tool machine of Exechon.
3 is a view showing a commercial touch probe.
Fig. 4 is a view for explaining the degree of freedom in which the Exechon Corporation parallel mechanism processing machine is constructed.
5 is a view illustrating a measurement error caused by the restraint motion when the touch probe is in contact with the circular master.
6 is a flowchart illustrating a measuring method of a meteorological measuring device according to the present invention.
7 is a view illustrating a state in which a touch probe used in the measuring method of the present invention is mounted on a spindle together with a coordinate axis.
8 is a view for explaining a situation that the touch probe in contact with the four points on the outer diameter of the circular master according to the measuring method of the present invention.
9 is a view illustrating a situation in which the touch probe moves 180 degrees to the center of the circular master and then rotates at an angle of 180 degrees according to the measuring method of the present invention and contacts the inside of the circular master by moving in the x and y directions.

Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings. However, this is not intended to limit the techniques described in this document to specific embodiments, but should be understood to cover various modifications, equivalents, and / or alternatives to the embodiments of this document. In connection with the description of the drawings, similar reference numerals may be used for similar components.

In addition, the expressions "first," "second," and the like used in this document may modify various components in any order and / or importance, and may distinguish one component from another. Used only and do not limit the components. For example, the 'first part' and the 'second part' may indicate different parts regardless of the order or importance. For example, without departing from the scope of rights described in this document, the first component may be called a second component, and similarly, the second component may be renamed to the first component.

Also, the terminology used herein is for the purpose of describing particular embodiments only and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise. The terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by one of ordinary skill in the art described in this document. Among the terms used in this document, terms defined in the general dictionary may be interpreted as having the same or similar meaning as the meaning in the context of the related art, and ideally or excessively formal meanings are not clearly defined in this document. Not interpreted as In some cases, even if terms are defined in the specification, they may not be interpreted to exclude embodiments of the present disclosure.

Figure 1 is a perspective view of the parallel machine processing machine 100 of Exechon, Figure 2 is a view showing the degree of freedom and coordinate system for the parallel machine processing machine 100 of Exechon.

It demonstrates with reference to FIG. 1 and FIG.

The measurement method of the meteorological measuring device according to the present invention will be described for the case where the meteorological measuring device is mounted on the parallel instrument processing machine 100 of Exechon. However, the measuring method according to the present invention is not limited to the type of processing machine, any processing machine in which restraint motion is generated can be used.

The structure of Exechon's parallel mechanism processing machine 100 will be briefly described.

Exechon's parallel mechanism processing machine 100 has a hybrid structure in which a three-axis parallel mechanism and a two-axis serial mechanism are combined.

The 5-axis parallel mechanism includes a base frame 110, a moving frame 120, a first link 130, a second link 140, a third link 150, a fourth link 160, and a fifth link 170. ).

The base frame 110 maintains a stationary state and forms a body 210 of the 5-axis parallel mechanism.

The moving frame 120 is disposed spaced apart from the base frame 110 by a predetermined interval and is movable with respect to the base frame 110.

One end of the first link 130, the second link 140, and the third link 150 may slide through the base frame 110, and the other end may be fixed to the moving frame 120.

Linear actuators may be adopted as the first to third links 150, and the first to third links 150 may be formed to have different lengths, respectively. As a result, the first to third links 150 fixed to the other end of the moving frame form a three-axis parallel mechanism.

One end of the fourth link 160 is hinged to the moving frame 120.

One end of the fifth link 170 is hinged to the fourth link 160, and the other end of the fifth link 170 is coupled to a tool. That is, the fifth link 170 corresponds to the spindle.

The fourth link 160 and the fifth link 170 form a biaxial series mechanism.

As described above, the Exechon's parallel mechanism processing machine 100 is connected to a three-axis parallel mechanism and a two-axis serial mechanism.

3 is a view showing a commercial touch probe 200.

It demonstrates with reference to FIG.

Touch probe 200 is made of a body 210 and the stylus 220, the ball 222 is mounted at the end of the stylus 220. When the ball 222 at the end of the stylus 220 contacts the object, the machine coordinate of the contact point is measured.

In the present invention, the touch probe 200 is adopted as a meteorological measuring device. However, the present invention is not limited thereto, and the measuring method of the meteorological measuring apparatus according to the present invention may be applied to a scanning probe, a laser displacement sensor, and the like.

The touch probe 200 is mounted on the spindle of Exechon's parallel mechanism processing machine 100 (hereinafter referred to as PKM).

4 is a view illustrating the degree of freedom of restraint of the parallel machine processing machine 100 of Exechon, and FIG. 5 is a view illustrating the measurement error caused by the restraint motion when the touch probe 200 contacts the circular master 400. to be.

It demonstrates with reference to FIG. 4 and FIG.

Since PKM has five axes, or five degrees of freedom, the spindle is constrained by one degree of freedom.

As shown in FIG. 4, when the third link 150 protrudes forward compared to the first link, the moving frame rotates about the S axis. The rotation about the S axis of the moving frame cannot be changed by the fourth link 160 and the fifth link 170. As a result, the fifth link 170, that is, the touch probe 200 mounted on the spindle, is forced to rotate dependently by the moving frame. The dependent angular change caused by this restraint motion causes an error to be included in the measurement of the weather measurement device.

Referring to FIG. 5, there is a difference between a point where the touch probe 200 contacts the circular master 400 when there is no restraint motion and a point where the touch probe 200 contacts the circular master 400 when there is a restraint motion. You can check it.

In the present invention, the dependent angle change amount is compensated for when measuring the workpiece by the meteorological measuring device.

6 is a flowchart illustrating a measuring method of a meteorological measuring device according to the present invention, and FIG. 7 is a view showing a state in which a touch probe 200 used in the measuring method of the present invention is mounted on a spindle together with a coordinate axis. 8 is a view illustrating a situation in which the touch probe 200 is in contact with the four points on the outer diameter of the circular master 400 according to the measuring method of the present invention, Figure 9 is a touch probe 200 according to the measuring method of the present invention After moving to the center of the circular master 400 is a view illustrating a situation of contacting the inside of the circular master 400 by rotating the angle of 180 degrees, moving in the x direction and the y direction.

It demonstrates with reference to FIGS. 6-9.

The measuring method of the meteorological measuring device according to the present invention includes a restraining motion compensation step 300, an offset error measurement step 310, the workpiece measurement step 320.

The restraint motion compensating step 300 is a step of calculating the dependent angle change amount of the meteorological measuring device generated due to the restraint motion of the spindle.

The restraint motion compensating step 300 calculates the dependent angle change of the meteorological measurement device generated by the restraint motion in the spindle axis direction through the kinematic calculation at the corresponding measurement position.

The offset error measurement step 310 is a step of measuring the degree of deviation of the center of the end of the weather measuring device with respect to the spindle axis while maintaining the state in which the spindle is rotated in the reverse direction by the dependent angle change amount.

The rotation of the spindle in the reverse direction by the dependent angle change amount is to exclude the influence of the restraint movement of the processing machine.

First, two straight lines crossing the circular master 400 contact the touch probe 200 at four points of the inner or outer diameter of the circular master 400 in contact with the circular master 400 to measure the mechanical coordinates.

The coordinates of the four points may be represented by p1 = [x1, y1, z1], p2 = [x2, y2, z2], p3 = [x3, y3, z3], p4 = [x4, y4, z4]. .

The average of the x-axis coordinates of the two points ( p ₁ , p ₃ ) contacted by the first straight line and the y-direction coordinates of the two points ( p ₂ , p ₄₎ contacted by the second straight line are averaged. The central coordinate ((x1 + x3) / 2) and the y-direction central coordinate ((y2 + y4) / 2 ₎ are calculated.

The center coordinates ( p _{center _of_circle} ) of the circular master 400 may be expressed as follows.

p _{center _of_circle} = [(x1 + x3) / 2, (y2 + y4) / 2, z1]

The center coordinates of the circular master 400 are offset by the offset (op, x, op, y) of the touch probe 200 with respect to the machine coordinate system.

And the touch probe 200 to the point ( p ₅ ) corresponding to the calculated x-axis center coordinate ((x1 + x3) / 2) and y-axis center coordinate ((y2 + y4) / 2 ₎ of the circular master 400 Move it.

The touch probe 200 is rotated at an angle of 180 degrees. When the touch probe 200 is rotated at an angle of 180 degrees, the touch probe 200 is positioned at twice the offset with respect to the center of the circular master 400.

In addition, the touch probe 200 is moved from the point ( p ₅ ) corresponding to the center coordinate of the circular master 400 in the x direction to the contact point ( p ₆ ) and the point moving in the y direction ( p ₇ ). Measure the machine coordinates.

If the deviation of p6 and p7 with respect to p5 is obtained by measuring the X and Y directions, the relationship between the offset and the measured value can be expressed as follows.

Here, θ ₆ and θ ₇ are the arc angles from the center of the circular master 400 to the contact points p6 and p7, R _master and r _stylus are the radius of the circular master 400 and the stylus 220 ball 222, x5 is the x coordinate of p 5 x6 is the x-coordinate of p6 , y5 is the y-coordinate of p 5, y7 is the y coordinate of p7 .

for θ ₆ and θ ₇ With a small angle approximation, the offset can be calculated simply as

Here, o _{x , p} , o _{y , and p} mean offset errors in the x direction and the y direction of the touch probe 200.

The workpiece measurement step 320 measures the shape of the workpiece while maintaining the state in which the spindle is rotated in the reverse direction by a dependent angle change amount, and then reflects the offset error measured in the offset error measurement step 310 to accurately measure the workpiece. It is a step of calculating.

The present invention calculates the dependent angle change of the meteorological measuring device caused by the restraint motion of a parallel machining machine, and reflects it in the offset error measurement and the workpiece measurement of the meteorological measuring device, thereby making it possible to measure the exact shape of the workpiece. There is an advantage.

While the above has been illustrated and described with respect to preferred embodiments of the present invention, the present invention is not limited to the specific embodiments described above, it is usually in the art without departing from the spirit of the invention claimed in the claims. Various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

100-Exechon's Parallel Machine Processing Machine 100
110-base frame
120-moving frame
130-first link
140-second link
150-Third Link
160-fourth link
170-Link 5
200-touch probe
210-body
220-stylus
221-stem
222-ball
300-restraint reward phase
310-Offset Error Measurement Step
320-workpiece measurement stage
400- round master

Claims (8)

In the measuring method of the meteorological measuring device mounted on the spindle of the processing machine to measure the shape of the workpiece,
Restraint motion compensation step (300) for calculating the dependent angle change amount of the meteorological measuring device generated by the restraint motion in the spindle rotation direction;
An offset error measuring step (310) of a meteorological measuring device for measuring the degree of deviation of the center of the end of the meteorological measuring device from the axis of the spindle while maintaining the state in which the spindle is rotated in the reverse direction by the dependent angle change amount;
The workpiece measurement step of measuring the shape of the workpiece while maintaining the state in which the spindle is rotated in the reverse direction by the dependent angle change amount to calculate the exact dimensions of the workpiece by reflecting the offset error measured in the offset error measurement step 310 (320);
Measuring method of the meteorological measuring device, characterized in that for measuring the shape of the workpiece by reflecting the dependent angle change amount reflected in the meteorological measuring device due to the restraint motion of the processing machine
The method of claim 1,
The meteorological measuring device is characterized in that the touch probe 200, measuring method of the meteorological measuring device.
The method of claim 2,
The offset error measuring step 310 is characterized by measuring the degree of deviation of the center of the stylus 220 ball 222 of the end of the touch probe 200 mounted to the spindle with respect to the spindle axis of rotation of the machining machine, Measurement method of the device
The method of claim 1,
The meteorological measuring device is a scanning probe, characterized in that the measuring method of the meteorological measuring device.
The method of claim 1,
The meteorological measuring device is a laser scanner, characterized in that the measuring method of the meteorological measuring device.
The method of claim 1,
The restraint motion compensating step 300 is to calculate the dependent angle change of the meteorological measuring device generated by the restraint motion of the spindle through the kinematic calculation at the measurement position, measuring method of the weather measuring device
The method of claim 3,
The offset error measurement step 310,
Two straight lines crossing the circular master 400 contact the touch probe 200 at four points of the inner diameter of the circular master 400 that contact the circular master 400, and measure the machine coordinates. Averaging the x-axis coordinates of the point ( p ₁ , p ₃ ), and averaging the y-direction coordinates of the two points ( p ₂ , p ₄₎ in contact with the second straight line, and then center coordinates ((x1 + x3 ₎ of the circular master. ) / 2) and the y-direction central coordinate ((y2 + y4) / 2 ₎ , where x1 is the x-direction coordinate of p ₁ , x3 is the x-direction coordinate of p ₃ , and y2 is the y-direction of p ₂ Direction coordinate, y4 is the y direction coordinate of p ₄ )
The touch probe 200 is moved to a point ( p ₅ ) corresponding to the calculated x-axis center coordinate ((x1 + x3) / 2) and y-axis center coordinate ((y2 + y4) / 2 ₎ of the circular master 400. Move it,
Rotate the touch probe 200 at an angle of 180 degrees,
The touch probe 200 is moved from the point ( p ₅ ) corresponding to the center coordinate of the circular master 400 in the x direction to be in contact with the point ( p ₆ ) and in the y direction to be in contact with the point ( p ₇ ). Measure the machine coordinates,

Here, o _{x , p} and o _{y , p} means offset errors in the x and y directions of the touch probe 200, and R _master and r _stylus are the circular master 400 and the stylus 220 ball 222. Is the radius of, x5 is the x-coordinate of p 5, x6 is the x-coordinate of p6 , y5 is the y-coordinate of p 5, y7 is the y-coordinate of p7 ), and the offset error of the circular master 400 is measured.
The method of claim 3,
The offset error measurement step 310,
Two straight lines crossing the circular master 400 contact the touch probe 200 at four points of the outer diameter of the circular master 400 which contact the circular master 400, and then measure the machine coordinates. Averaging the x-axis coordinates of the point ( p ₁ , p ₃ ), and averaging the y-direction coordinates of the two points ( p ₂ , p ₄₎ in contact with the second straight line, and then center coordinates ((x1 + x3 ₎ of the circular master. ) / 2) and the y-direction central coordinate ((y2 + y4) / 2 ₎ , where x1 is the x-direction coordinate of p ₁ , x3 is the x-direction coordinate of p ₃ , and y2 is the y-direction of p ₂ Direction coordinate, y4 is the y direction coordinate of p ₄ )
The touch probe 200 is moved to a point ( p ₅ ) corresponding to the calculated x-axis center coordinate ((x1 + x3) / 2) and y-axis center coordinate ((y2 + y4) / 2 ₎ of the circular master 400. Move it,
Rotate the touch probe 200 180 degrees,
The touch probe 200 is moved from the point ( p ₅ ) corresponding to the center coordinate of the circular master 400 in the x direction to be in contact with the point ( p ₆ ) and in the y direction to be in contact with the point ( p ₇ ). Measure the machine coordinates,
Equation

Here, o _{x , p} and o _{y , p} means offset errors in the x and y directions of the touch probe 200, and R _master and r _stylus are the circular master 400 and the stylus 220 ball 222. Is the radius of, x5 is the x-coordinate of p 5, x6 is the x-coordinate of p6 , y5 is the y-coordinate of p 5, y7 is the y-coordinate of p7 ), and the offset error of the circular master 400 is measured.

Images