JP6960376B2 - Method for identifying motion error of feeder - Google Patents

Description

The present invention is a method of identifying a motion error of the feeder in a two-dimensional plane defined by a reference axis corresponding to the two linear feed axes in a feeder having at least two orthogonal linear feed axes. Regarding.

As a device provided with the feeding device, conventionally, for example, a spindle for holding a tool and a table on which a work is attached are configured to be relatively moved in the orthogonal three-axis directions of the X-axis, the Y-axis, and the Z-axis. Machine tools that have been made are known.

In a machine tool having such a configuration, the motion error includes a positioning error in each of the X-axis, Y-axis, and Z-axis feed axes (that is, an X-axis feed device, a Y-axis feed device, and a Z-axis feed device), and each feed. Considering the straightness of the shaft and the like, as a numerical control device for compensating for such a motion error, a numerical control device disclosed in Japanese Patent Application Laid-Open No. 8-152909 (Patent Document 1 below) has been proposed.

By the way, in recent years, as shown in FIG. 5, the motion error (positioning error) of the machine tool in the three-dimensional space includes the translational motion error of each feed axis, the angle error of each feed axis, and the mutual feed axis. It is thought that the errors related to the squareness of are expressed in a state in which they influence each other. Therefore, by obtaining each such error, it is possible to identify the accurate motion error. The definition of each error shown in FIG. 5 is as follows.
_EXX is the positioning error of the X-axis feeder in the X-axis direction.
_EYY is the positioning error of the Y-axis feeder in the Y-axis direction.
_EZZ is the positioning error of the Z-axis feeder in the Z-axis direction.
_EYX is the straightness error (Y-axis direction) in the X-axis-Y-axis plane of the X-axis feeder.
_EZX is the straightness error (Z-axis direction) in the X-axis-Z-axis plane of the X-axis feeder.
_EXY is the straightness error (X-axis direction) in the Y-axis-X-axis plane of the Y-axis feeder.
E _ZY is straight in the Y-axis -Z-axis plane of the Y-axis feeding device error (Z axis direction),
_EXZ is the straightness error (X-axis direction) in the Z-axis-X-axis plane of the Z-axis feeder.
_EYZ is the straightness error (Y-axis direction) in the Z-axis-Y-axis plane of the Z-axis feeder.
_EAX is the angular error around the X-axis in the X-axis feeder.
_EAY is the angular error around the X-axis in the Y-axis feeder.
_EAZ is the angular error around the X-axis in the Z-axis feeder.
_EBX is the angular error around the Y-axis in the X-axis feeder.
E _BY is the angular error around the Y axis in the Y axis feeder.
_EBZ is the angular error around the Y-axis in the Z-axis feeder.
E _CX is the angle error around the Z axis in the X axis feeder.
_ECY is the angular error around the Z axis in the Y axis feeder.
_ECZ is the angle error around the Z axis in the Z axis feed device.
EA _{(0Y) Z} is the right angle error between the Z-axis feeder and the ideal Y-axis.
_{EB (0X) Z} is the right angle error between the Z-axis feeder and the ideal X-axis.
EC _{(0X) Y} is a right angle error between the Y-axis feeder and the ideal X-axis.
As the other error factors, E _{B (0Z} is perpendicular error between Y-axis feeding device and is perpendicular error of the Z-axis of the ideal E _{A (0Z) Y, X-axis} feed device and the ideal Z axis _{) X , EC (0Y) X,} which is a right-angled error between the X-axis feeder and the ideal Y-axis, can be considered.

Conventionally, as a measuring method for measuring such an error, a measuring method using a measuring device as shown in FIGS. 6 and 7 has been proposed. The machine tool 50 as an example shown in FIG. 6 is composed of a bed 51 whose upper surface is a work mounting surface (so-called table), a gate-shaped frame 52, and a saddle 53. The frame 52 is arranged so that its horizontal portion is located above the bed 51, and its two vertical portions engage with the side portions of the bed 51, respectively, so that the frame 52 can move in the Y-axis direction as a whole. It has become. Further, the saddle 53 is engaged with the horizontal portion of the frame 52 and is movable in the X-axis direction along the horizontal portion, and the main shaft 54 of the saddle 53 is movable in the Z-axis direction. Moreover, it is rotatably held around an axis parallel to the Z axis. The X-axis, Y-axis, and Z-axis are reference axes that are orthogonal to each other, and each feed axis corresponding to the reference axis is an X-axis feed device (not shown), a Y-axis feed device (not shown), and a Y-axis feed device (not shown). It is composed of a Z-axis feed device (not shown).

Each of the above errors is measured using a laser length measuring device 30 installed on the bed 51 and a mirror 35 mounted on the spindle 54. Specifically, first, the laser length measuring device 30 is installed at a predetermined position, for example, at four locations shown by solid lines in FIG. 6, and the mirror 35 is attached to the main shaft 54. Then, by positioning and controlling the X-axis feed device, the Y-axis feed device, and the Z-axis feed device at regular intervals, the mirror 35 is placed at each grid point in which the three-dimensional space is divided into grids at regular intervals. By positioning and irradiating the mirror 35 with laser light from each laser length measuring device 30 at each lattice point and receiving the reflected light to the laser length measuring device 30, each laser length measuring device 30 and the mirror 35 Measure the distance between.

Then, based on the measurement data obtained as described above, the position of the mirror 35 at each of the lattice points in the three-dimensional space is calculated according to the principle of the three-sided survey method, and the calculated position data and the position data are calculated. Each of the above errors is calculated by analyzing.

The laser length measuring device 30 is configured so that the laser interferometer 32 can be swiveled around the center point of the reference sphere 31 shown in FIG. 7, and the laser interferometer 30 is moved in accordance with the movement of the mirror 35. Is configured to be able to automatically track the mirror 35 by turning and moving the mirror 35.

The laser length measuring device 30 having such a structure is very expensive, and it is impractical to use four laser length measuring devices 30 in the above measurement. Therefore, conventionally, one laser length measuring device 30 is used, and the laser length measuring device 30 is sequentially moved and installed at four places, and the mirror 35 is positioned at each of the grid points at each installation position. The distance between the laser length measuring device 30 and the mirror 35 was measured.

Japanese Unexamined Patent Publication No. 8-152909

However, when the motion error is measured by using one laser length measuring device 30 as in the conventional case, although the cost required for the laser length measuring device 30 is reduced, each installation position of the laser length measuring device 30 is reduced. In the above, since it is necessary to repeatedly execute the operation of positioning the mirror 35 at each of the lattice points, there is a problem that the measurement takes a long time and the operation is complicated and troublesome. A measurement using one laser length measuring device 30 requires four times as long as a simple calculation as compared with a measurement using four laser length measuring devices 30.

In addition, when evaluating the kinetic performance of a machine tool, when evaluating including changes over time, such as evaluating the effects of thermal deformation caused by the operation of the machine tool, the measurement is performed as described above. If it takes a long time, the exercise performance changes during the measurement, so that there is a problem that accurate exercise performance cannot be evaluated.

The present invention has been made in view of the above circumstances, and identification that can identify the motion error of the feeder in a shorter time than in the conventional case even in the measurement using one laser length measuring device. The purpose is to provide a method.

The present invention for solving the above problems
It has at least two linear feed shafts arranged so as to be orthogonal to each other, and the two linear feed shafts are used to drive at least one of the two objects to be positioned. For a feeder configured to position relative positions between two objects, identify the motion error of the feeder in a two-dimensional plane defined by a reference axis corresponding to the two linear feed axes. It ’s a method,
With the laser length measuring device disposed on one of the objects and the reflector disposed on the other object, the feeder is driven to be between the two objects in the two-dimensional plane. The distance between the two objects is measured by the laser length measuring device while sequentially positioning the relative positions of the two objects at a plurality of designated positions.
Distance data measured by the laser length measuring device, designated position data in the two-dimensional plane of the other object when it is assumed that the position of one object in the two objects is fixed, and fixed. The two-dimensional plane of the two objects based on the position data of the predetermined reference position of the laser length measuring device or the reflector arranged on the objects in the two-dimensional plane and the error parameter of the feeder. Constructed to identify relative motion errors within
The error parameters include an error parameter set from the geometric model of the feeder, and an error related to displacement that occurs with the passage of time when the two objects are positioned at the same designated position (relative position). The present invention relates to a motion error identification method including parameters.

According to the identification method of the present invention, first, the laser length measuring device is arranged on one of the objects, and the feeder is driven in a state where the reflecting mirror is arranged on the other object. While sequentially positioning the relative positions between the two objects in the two-dimensional plane at a plurality of designated positions, the distance between the two objects is measured by the laser length measuring device.

Then, 1) the distance data measured by the laser length measuring device and 2) the other object when it is assumed that the position of one object in the two objects is fixed to the designated position. Data (conversion designated position data) related to the designated position (conversion designated position) converted to the position on the two-dimensional plane, and 3) a predetermined reference position for the laser length measuring instrument or reflector arranged on the fixed object. With the passage of time, the position data in the two-dimensional plane, 4) the error parameters set from the geometric model of the feeder, and 5) the two objects are positioned at the same designated position. The relative motion error of the two objects positioned by the feeder in the two-dimensional plane is identified based on the error parameters related to the displacement caused by the above.

The designated position regarding the relative position between the two objects is not limited as long as it is a position in the two-dimensional plane, but to give an example, the adjacent conversion designated positions are connected. The position can be such that the line forms a rectangular shape.

Thus, according to this motion error identification method, repeated operations are repeated when identifying the motion error of the two objects positioned by the feeder using one laser length measuring device. Instead, it is possible to identify the motion error with a single operation of measuring the distance between the two objects with a laser length measuring device while sequentially positioning the relative positions between the two objects at a plurality of designated positions. Therefore, it is possible to identify the motion error in a very short time as compared with the conventional case.

Therefore, even when it is necessary to evaluate the change with time when evaluating the motion performance of the feed device, the motion error can be identified by using the motion error identification method according to the present invention. Accurate exercise performance can be evaluated.

但し、Ｙ_ｎ及びＺ _ｍ は２つの対象物の内の一方の対象物の位置を固定したと仮定したときの他方の対象物のＹ−Ｚ平面における指定位置ｐ_ｎ，ｍ（Ｙ_ｎ，Ｚ_ｍ）である。また、ｎ＝１，．．．，Ｎであり、ｍ＝１，．．．，Ｍであり、Ｎ，Ｍは整数である。
Ｅ_ＹＹ（Ｙ_ｎ）は、Ｙ軸に沿った直線送り軸（Ｙ軸送り軸）のＹ軸方向における位置決め誤差、
Ｅ_ＺＺ（Ｚ_ｍ）は、Ｚ軸に沿った直線送り軸（Ｚ軸送り軸）のＺ軸方向における位置決め誤差、
Ｅ_ＹＺ（Ｚ_ｍ）は、Ｚ軸送り軸のＹ軸−Ｚ軸平面における真直誤差（Ｙ軸方向）、
Ｅ_ＺＹ（Ｙ_ｎ）は、Ｙ軸送り軸のＹ軸−Ｚ軸平面における真直誤差（Ｚ軸方向）、
Ｅ_ＡＹ（Ｙ_ｎ）は、Ｙ軸送り軸における、Ｙ軸及びＺ軸に直交する軸まわりの角度誤差、
Ｅ_{Ａ(０Ｙ)Ｚ}は、理想のＹ軸に対するＺ軸送り軸の直角誤差であり、前記送り装置の幾何学モデルから設定される誤差パラメータである。
また、Ｔ_Ｙ及びＴ_Ｚは、前記２つの対象物を同一の指定位置に位置決めした状態で、時間経過に伴って生じる誤差パラメータであって、Ｔ_Ｙは前記２つの対象物間のＹ軸方向の変位であり、Ｔ_Ｚは同じくＺ軸方向の変位である。
これらの誤差の内、Ｅ_ＹＹ（Ｙ_ｎ）、Ｅ_ＺＺ（Ｚ_ｍ）、Ｔ_Ｙ及びＴ_Ｚは、直接測定することによって得られる。
また、その他の誤差、即ち、Ｅ_ＹＺ（Ｚ_ｍ）、Ｅ_ＺＹ（Ｙ_ｎ）、Ｅ_ＡＹ（Ｙ_ｎ）及びＥ_{Ａ(０Ｙ)Ｚ}は、下記数式２によって得られる値を最小にする値として得られる。

但し、Ｐは固定対象物に配設されたレーザ測長器又は反射鏡についての所定基準位置の前記２次元平面内における位置であり、ｄ_ｎ，ｍはレーザ測長器によって測定された距離データである。
More specifically, in the motion error identification method according to the present invention,
When one reference axis of the two-dimensional plane is the Y axis and the other reference axis is the Z axis, the motion error Δpn _{, m} , that is, the motion error ΔY _n (Y _n , Z _m ) in the Y-axis direction and the Z axis. The directional motion error ΔZ _m (Y _n , Z _m ) can be calculated by the following equation 1.

However, Y _n and Z _{m are designated positions pn, m} (Y _n , Z) in the YZ plane of the other object assuming that the position of one object among the two objects is fixed. _m ). In addition, n = 1,. .. .. , N, and m = 1,. .. .. , M, and N, M are integers.
E _{YY (Y n),} the positioning error in the Y-axis direction of the linear feed axis along the Y-axis (Y-axis feed shaft),
E _{ZZ (Z m),} the positioning error in the Z-axis direction of the linear feed axis along the Z-axis (Z-axis feed shaft),
_EYZ (Z _m ) is the straightness error (Y-axis direction) of the Z-axis feed axis in the Y-axis-Z-axis plane.
E _ZZ (Y _n ) is the straightness error (Z-axis direction) of the Y-axis feed axis in the Y-axis-Z-axis plane.
E _AY (Y _n ) is the angular error around the Y-axis feed axis that is orthogonal to the Y-axis and Z-axis.
EA _{(0Y) Z} is a right angle error of the Z-axis feed axis with respect to the ideal Y-axis, and is an error parameter set from the geometric model of the feed device.
Further, T _Y and T _Z is in a state of positioning the two objects at the same specified position, a error parameters occurring with time, T _Y is the Y-axis direction between the two objects a displacement, T _Z is the same Z-axis direction of displacement.
Of these _{errors, E YY (Y n),} E ZZ (Z m), T Y and _{T Z} can be obtained by direct measurement.
In addition, other errors, that is, _EYZ (Z _m ), E _ZY (Y _n ), E _AY (Y _n ), and E _{A (0} Y) Z, are values that minimize the value obtained by the following equation 2. can get.

However, P is the position in the two-dimensional plane of the predetermined reference position of the laser length measuring device or the reflecting mirror arranged on the fixed object, and d _{n and m} are the distance data measured by the laser length measuring device. Is.

According to the motion error identification method according to the present invention, when identifying the motion error of the two objects positioned by the feeder using one laser length measuring device, without repeating repeated operations. Since the relative position between two objects is sequentially positioned at a plurality of designated positions, and the distance between the two objects is measured by a laser length measuring device, the motion error can be identified by a single operation. , The motion error can be identified in a very short time as compared with the conventional case.

Therefore, when evaluating the kinetic performance of the feeding device, it is possible to evaluate the accurate kinetic performance of the feeding device even when it is necessary to evaluate the change over time.

It is explanatory drawing for demonstrating the motion error identification method which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the motion error identification method which concerns on this Embodiment. It is explanatory drawing which showed the motion error identified by the motion error identification method which concerns on this embodiment. It is explanatory drawing which showed the motion error identified by the motion error identification method which concerns on this embodiment. It is explanatory drawing which showed the error parameter which causes motion error. It is explanatory drawing for demonstrating the conventional method for identifying a motion error. It is explanatory drawing which showed the laser length measuring instrument and the reflector.

Hereinafter, specific embodiments of the present invention will be described. In this example, it is assumed that the motion error of the machine tool shown in FIG. 1 is identified.

First, the schematic configuration of the machine tool 1 will be described. As shown in FIG. 1, the machine tool 1 of this example has a bed 2 having an alphabetical T shape when viewed from a plane, a column 3 arranged on one side of the bed 2, and the other of the bed 2. The table 6 arranged on the side, the saddle 4 arranged on the side surface (front surface) of the column 3 on the table 6 side, the spindle 5 rotatably supported by the saddle 4, and the spindle 5 are rotated. A spindle motor (not shown), an X-axis feed device 10 that moves the column 3 along the arrow X-axis, a Y-axis feed device 15 that moves the saddle 4 along the arrow Y-axis, and the table 6. Is provided with a Z-axis feed device 20 or the like for moving the Z-axis along the Z-axis. The X-axis, Y-axis, and Z-axis are reference axes that are orthogonal to each other.

The X-axis feed device 10 includes a pair of guide rails 14 and 14 arranged in parallel along the X-axis, an X-axis feed motor 11 which is a servo motor, and a ball screw driven by the X-axis feed motor 11. 12. A ball nut (not shown) screwed into the ball screw 12 and fixed to the lower surface of the column 3, and a bearing 13 that rotatably supports both ends of the ball screw 12 (one bearing is shown). It is composed of (screw) and so on. In the X-axis feed device 10, the column 3 is guided by the guide rails 14 and 14 and moves along the X-axis by driving the X-axis feed motor 11 and rotating the ball screw 12.

Similarly, the Y-axis feed device 15 is driven by a pair of guide rails 19 and 19 arranged in parallel along the Y-axis, a Y-axis feed motor 16 which is a servo motor, and the Y-axis feed motor 16. A ball screw 17, a ball nut (not shown) screwed into the ball screw 17 and fixed to the surface of the saddle 4 on the column 3 side, and a bearing 18 that rotatably supports both ends of the ball screw 17. (One bearing is not shown) and so on. In the Y-axis feed device 15, the saddle 4 is guided by the guide rails 19 and 19 and moves along the Y-axis by driving the Y-axis feed motor 16 to rotate the ball screw 17.

Further, the Z-axis feed device 20 is driven by a pair of guide rails 24, 24 arranged in parallel along the Z-axis, a Z-axis feed motor 21 which is a servomotor, and the Z-axis feed motor 21. It is composed of a ball screw 22, a ball nut (not shown) screwed into the ball screw 22 and fixed to the lower surface of the table 6, bearings 23, 23 that rotatably support both ends of the ball screw 22, and the like. Will be done. In the Z-axis feed device 20, the table 6 is guided by the guide rails 24 and 24 and moves along the Z-axis by driving the Z-axis feed motor 21 and rotating the ball screw 22.

Thus, the machine tool 1 appropriately drives the X-axis feed device 10, the Y-axis feed device 15, and the Z-axis feed device 20 so that the spindle 5 and the table 6 are appropriately relative to each other in the three-dimensional space. Can be moved.

Next, a method for identifying the motion error of the machine tool 1 will be described. In this example, the motion error of the machine tool 1 is measured at the following time points, and the motion error of the machine tool 1 in consideration of the thermal deformation generated in the machine tool 1 is identified and evaluated.
1) 1st measurement: Measured in the initial state
2) 2nd measurement: After the 1st measurement, the spindle 5 is rotated at a rotation speed of 4000 min ^-1 for 2 hours and then measured.
3) Third measurement: After the second measurement, the spindle 5 is further rotated at a rotation speed of 8000 min ^-1 for 2 hours before measurement.
4) 4th measurement: After the 3rd measurement, the spindle 5 is further rotated at a rotation speed of 12000 min ^-1 for 2 hours.

In this example, the motion error when the spindle 5 and the table 6 are moved in the Y-axis-Z-axis plane is identified, but the motion error when the spindle 5 and the table 6 are moved in the X-axis-Y-axis plane, and The motion error when moving in the X-axis-Z-axis plane can be identified in the same way, and by comprehensively evaluating the motion error in these three planes, as a result, the X-axis and the Y-axis can be identified. And the motion error of the machine tool 1 in the three-dimensional space with the Z axis as the reference axis can be identified.

Hereinafter, a method for measuring the motion error and a method for identifying the motion error at each of the first to fourth measurements will be described. In this example, the same procedure is executed at each of the first to fourth measurements.

First, the main shaft 5 by the Y-axis feeding device 15 by the main shaft 5 and the table 6 and a positioning error in the Y-axis direction when moving at a predetermined pitch along the Y-axis E _{YY (Y n),} and Z-axis feed apparatus 20 And the table 6 are moved along the Z axis at a predetermined pitch, and the positioning error E _ZZ (Z _m ) in the Z axis direction is measured. n = 1, 1. .. .. , N, m = 1,. .. .. , M, and N, M are integers. The measuring instrument used for this measurement is not particularly limited, and the measurement can be performed by using the laser length measuring instrument 30 of this example, another laser interferometer, an autocollimator, or the like.

In addition, the displacement of the spindle 5 with time with respect to a predetermined reference position is measured. For example, in each of the 1st to 4th measurements, with the table 6 positioned at a predetermined position, for example, using an appropriate displacement meter, the Y between the reference position set on the table 6 and the spindle 5 Axial displacement _TY and Z-axis displacement _TZ are measured.

Next, the laser length measuring device 30 shown in FIG. 7 is installed on the table 6, the mirror 35 is mounted on the spindle 5, and then, as shown in FIG. 2, the table 6 is set to the Z axis by the Z-axis feed device 20. _{The distance dn, m} between the laser length measuring device 30 and the mirror 35 is measured by the laser length measuring device 30 while sequentially positioning the _{designated positions P 1, 1} to P _{1, M} along the predetermined pitch.

Next, the laser length measuring device 30 uses the laser length measuring device 30 to sequentially position _{the main shaft 5 from the designated positions P1, M} to _{PN, M} at a predetermined pitch along the Y axis by the Y-axis feeding device 15. _{The distance d n, m} between the mirror 35 and the mirror 35 is measured.

Then, in the same manner, the Z-axis feed device 20 _{sequentially positions the table 6 from the designated positions PN, M} to _{PN, 1} at a predetermined pitch along the Z-axis, and the laser length measuring device 30 measures the laser. _{The distance d n, m} between the length device 30 and the mirror 35 is measured.

After that, the Y-axis feed device 15 sequentially positions the spindle 5 along the Y-axis at a predetermined pitch from the designated positions _{PN-1, 1} to P _{2, 1,} and the laser length measuring device 30 measures the laser length. _{The distance d n, m} between the vessel 30 and the mirror 35 is measured.

As described above, the movement path connecting the laser length measuring instrument 30 and the mirror 35 at the adjacent designated positions _{pn, m} (Y _n , Z _m ) draws a rectangular line in the Y-axis-Z-axis plane. The distance between the laser length measuring instrument 30 and the mirror 35 is measured at _{each designated position pn, m} (Y _n , Z _m ) by moving the laser relative to each other at a predetermined pitch as drawn. As shown in FIG. 2, the relative movement between the laser length measuring device 30 and the mirror 35 is such that the mirror 35 is moved in the Y-axis −Z axis plane with the laser length measuring device 30 fixed. It can be thought of as a moving mode. Further, the Y-axis-Z-axis plane including the movement path includes the center point of the reference sphere 31 of the laser length measuring instrument 30.

Next, 1st - obtained during each measurement of the 4th, the positioning error _E YY in the Y-axis direction of the main shaft 5 _(Y n), the positioning error _E ZZ Z-axis direction of the table 6 _(Z m), displacement T _Y in the Y-axis direction of the main shaft _5, and displacement T _Z of the Z-axis direction of the main shaft _5, and based on the distance data d _n, the _m between the laser measurement device 30 and the mirror 35, respectively commanded position p The kinetic error Δpn _{, m with respect to n, m} (Y _n , Z _m ), that is, the kinetic error ΔY _n (Y _n , Z _m ) in the Y-axis direction and the kinetic error ΔZ _m (Y _n , Z _m ) in the Z-axis direction. To identify.

但し、Ｅ_ＹＺ（Ｚ_ｍ）は、Ｚ軸送り軸のＹ軸−Ｚ軸平面における真直誤差（Ｙ軸方向）、
Ｅ_ＺＹ（Ｙ_ｎ）は、Ｙ軸送り軸のＹ軸−Ｚ軸平面における真直誤差（Ｚ軸方向）、
Ｅ_ＡＹ（Ｙ_ｎ）は、Ｙ軸送り軸における、Ｙ軸及びＺ軸に直交する軸まわりの角度誤差、
Ｅ_{Ａ(０Ｙ)Ｚ}は、理想のＹ軸に対するＺ軸送り軸の直角誤差であり、前記送り装置の幾何学モデルから設定される誤差パラメータである。 Specifically, the motion error Δpn _{, m} can be calculated by the following mathematical formula 1.

However, _EYZ (Z _m ) is the straightness error (Y-axis direction) of the Z-axis feed axis in the Y-axis-Z-axis plane.
E _ZZ (Y _n ) is the straightness error (Z-axis direction) of the Y-axis feed axis in the Y-axis-Z-axis plane.
E _AY (Y _n ) is the angular error around the Y-axis feed axis that is orthogonal to the Y-axis and Z-axis.
EA _{(0Y) Z} is a right angle error of the Z-axis feed axis with respect to the ideal Y-axis, and is an error parameter set from the geometric model of the feed device.

但し、Ｐは固定した状態と観念されるレーザ測長器３０の基準位置（前記基準球３１の中心位置）のＹ軸−Ｚ軸平面内における位置である。 And these four error parameters _{E YZ (Z m), E} ZY (Y n), E AY (Y n) and E _{A (0Y) Z} is a value that minimizes a value obtained by the following equation 2 can get.

However, P is a position in the Y-axis-Z-axis plane of the reference position (center position of the reference sphere 31) of the laser length measuring instrument 30 which is considered to be in a fixed state.

As described above, the spindle 5 and the table 6 operated by the Y-axis feed device 15 and the Z-axis feed device 20 calculated based on the data obtained by each of the first to fourth measurements. _{The motion errors Δpn and m} in the Y-axis −Z-axis plane between and are shown in FIG. In FIG. 3, the designated positions _{pn and m} are indicated by ●, the motion errors Δpn _{and m} during the first measurement are indicated by ○, the motion errors Δpn _{and m} during the second measurement are indicated by □, and the motion errors Δpn and m during the third measurement are indicated by □. The motion error Δpn _{, m} at the time of the fourth measurement is represented by ▲, and the motion error Δpn _{, m} at the time of the fourth measurement is represented by ■. In FIG. 3, the motion errors Δpn _{and m} are plotted at a magnification of 1000 times.

As can be seen from FIG. 3, in this machine tool 1, as the spindle 5 is rotated at high speed, the error in the Z-axis direction increases, and the diagram is shifted to the negative direction (left side) of the Z-axis. This means that the heat generated in the spindle 5 is increased by rotating the spindle 5 at high speed, and the spindle 5 is displaced to the table 6 side, that is, in the negative direction of the Z axis due to the accompanying thermal deformation (thermal expansion). ing. This displacement T _Z of the Z-axis direction of the main shaft 5 has been measured, likewise when even together cancel displacement T _Y in the Y-axis direction become known by measurement, 1st - by the measurement of the 4th _{The motion errors Δpn and m} in the Y-axis −Z-axis plane between the obtained spindle 5 and the table 6 are as shown in FIG.

_{Thus, the pure motion error Δpn, m} in the Y-axis-Z-axis plane between the spindle 5 and the table 6 operated by the Y-axis feed device 15 and the Z-axis feed device 20 is shown in FIG. It is expressed as canceling the thermal deformation of the spindle 5. According to FIG. 4, the kinetic performance of the machine tool 1 in the Y-axis-Z-axis plane does not depend on the rotational speed of the spindle 5, and depends on the kinetic performance of the Y-axis feed device 15 and the Z-axis feed device 20. You can see that it depends.

As described above in detail, according to the motion error identification method of the present embodiment, the positioning error _E YY in the Y-axis direction of the main shaft 5 _(Y n), the positioning error _E ZZ Z-axis direction of the table 6 _(Z m), displacement T _Y in the Y-axis direction of the main shaft _5, and with measuring the displacement T _Z of the Z-axis direction of the main shaft 5, and a laser measurement device 30 and the mirror 35 is its relative movement path Y axis -Z axis plane By moving relative to each other at a predetermined pitch so as to draw a rectangular line inside and measuring the distance between the laser length measuring instrument 30 and the mirror 35 at each designated position, the main axis 5 and the main axis 5 in the Y-axis-Z-axis plane can be measured. The motion error between the table 6 and the table 6 can be identified, and the motion error can be identified in an extremely short time as compared with the conventional case.

That is, conventionally, as described above, the laser length measuring instruments 30 are installed at at least four different positions, and in each installed state, the mirror 35 is positioned at each lattice point set in the three-dimensional space. Since it is necessary to repeat the measurement operation of measuring the distance with the laser length measuring device 30 at least four times, the measurement takes an extremely long time. Therefore, for example, in the case of identifying the motion error in consideration of the thermal deformation of the machine tool 1 as in this example, in this conventional method, the thermal deformation of the machine tool 1 is reached by the time the measurement is completed. Since the state is changing, it was not possible to evaluate the accurate exercise performance of the machine tool 1.

On the other hand, in the motion error identification method of this example, since the motion error in the two-dimensional plane is identified, the designated position (measurement point) to be relatively moved between the laser length measuring device 30 and the mirror 35 is set. Since the number of measurements by the laser length measuring device 30 can be remarkably reduced, the measurement time can be remarkably reduced as compared with the conventional one. Thus, according to the motion error identification method of this example, even when evaluating a change over time in the motion performance of the machine tool 1, such as the influence of thermal deformation, the motion performance can be accurately evaluated.

Although one embodiment of the present invention has been described above, the specific embodiments that the present invention can take are not limited thereto. For example, in the above example, the motion error when the spindle 5 and the table 6 are moved in the Y-axis-Z-axis plane by the Y-axis feed device 15 and the Z-axis feed device 20 is identified. The motion error when the spindle 5 and the table 6 are moved in the X-axis-Z-axis plane by the X-axis feed device 10 and the Z-axis feed device 20 is identified by the same method as in the above example. You may do so. Alternatively, the motion error when the spindle 5 and the table 6 are moved in the X-axis-Y-axis plane by the X-axis feed device 10 and the Y-axis feed device 15 may be identified by the same method as in the above example. good.

Further, based on the motion errors in the X-axis-Y-axis plane, the X-axis-Z-axis plane, and the Y-axis-Z-axis plane thus obtained, the X-axis, Y-axis, and the machine tool 1 The motion error in the three-dimensional space with the Z axis as the reference axis may be identified. Further, the identification process of such motion error, error parameter _E XX as described _{above, E YY, E ZZ, E} YX, E ZX, E XY, E ZY, E XZ, E YZ, E AX, E AY, E _{AZ, E BX, E BY,} E BZ, E CX, E CY, E CZ, E A (0Y) Z, E B (0X) Z, E C (0X) Y, E A (0Z) Y, E B _{(0Z) X} and EC _{(0Y) X} can be derived.

Further, the feed device capable of identifying the motion error according to the present invention is not limited to the feed device included in the machine tool 1 having the above-mentioned structure, and any feed device having linear feed axes orthogonal to each other can be used. The feeding device may have any structure, and further, when it is a machine tool, it is not limited to the above-mentioned structure.

Again, the description of the embodiments described above is exemplary in all respects and not restrictive. Modifications and changes can be made as appropriate for those skilled in the art. The scope of the present invention is shown not by the above-described embodiment but by the scope of claims. Further, the scope of the present invention includes modifications from the embodiment within the scope of the claims and within the scope of the claims.

1 Machine tool 2 Bed 3 Column 4 Saddle 5 Spindle 6 Table 10 X-axis feed device 15 Y-axis feed device 20 Z-axis position feed device 30 Laser length measuring device 31 Reference ball 32 Laser interferometer 35 Mirror

Claims (1)

At least two linear feed axes arranged so as to be orthogonal to each other, a Y-axis feed axis as a linear feed axis along the Y-axis which is a reference axis, and a reference axis orthogonal to the Y-axis. It has a Z-axis feed axis as a linear feed axis along the Z axis, and the two linear feed axes are used to drive at least one of the two objects to be positioned to drive the two objects. A method of identifying a motion error of a feeder in a Y-axis-Z-axis plane defined by the Y-axis and the Z-axis for a feeder configured to position relative positions between objects. ,
The positioning error _E YY _(Y n) in the Y-axis direction of the Y-axis feed shaft, and measure the positioning error _E ZZ _{(Z m)} in the Z axis direction of the Z-axis feed shaft,
It is an error parameter that occurs with the passage of time when the two objects are positioned at the same relative position, which is the same relative position, and is the displacement _TY and Z axis in the Y-axis direction between the two objects. with measuring the direction of displacement T _Z,
With the laser length measuring device disposed on one of the objects and the reflecting mirror disposed on the other object, the feeder is driven to drive the two objects in the Y-axis-Z-axis plane. While sequentially positioning the relative positions between the objects at a plurality of designated positions, the distances dn _{and m} between the two objects are measured by the laser length measuring device, respectively.
_{Distance data d n, m} measured by the laser length measuring device, the Y-axis-Z-axis plane of the other object assuming that the position of one object in the two objects is fixed. Specified position data _{pn, m} (Y _n , Z _m ), position data P in the Y-axis-Z-axis plane of a predetermined reference position for a laser length measuring device or a reflector arranged on a fixed object. , and the feed device error parameters in which the positioning error _E YY _(Y n), the positioning error _E ZZ _(Z m), Y-axis direction of the straight error _{E YZ} in the Y-axis -Z axis plane of the Z-axis feed shaft _(Z m), said Y-axis feed shaft of the Y-axis -Z-axis Z-axis direction of the straight error in plane _E ZY _(Y n), in the Y-axis feed shaft, around the axis perpendicular to the Y-axis and Z-axis Angle error E _AY (Y _n ), an error parameter set from the geometric model of the feeder, and the error E _{A (0Y) Z} of the Z-axis feed axis with respect to the Y axis, and with the passage of time. the Y-axis direction displacement T _Y, and based on the displacement T _Z of the Z-axis direction resulting Te,
Calculated by the motion error Delta] p _n, of motion errors Y-axis direction, which is the _{m ΔY n (Y n, Z} m) and the Z-axis direction of the motion error _{ΔZ m (Y n, Z m} ) Equation 1 below the feed device A method for identifying motion errors, which is characterized in that the method is used.

However, n = 1,. .. .. , N, and m = 1,. .. .. , M, and N, M are integers.
Further, the position data P is a known value. Further, the errors _EYZ (Z _m ), E _ZY (Y _n ), E _AY (Y _n ) and E _{A (0} Y) Z are obtained as values that minimize the values obtained by the following mathematical formula 2.

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