WO2001059409A2

WO2001059409A2 - Position measuring system and restricted guidance for a two-dimensional actuator

Info

Publication number: WO2001059409A2
Application number: PCT/AT2001/000029
Authority: WO
Inventors: Heinz Peter Brandstetter
Original assignee: Heinz Peter Brandstetter
Priority date: 2000-02-07
Filing date: 2001-02-07
Publication date: 2001-08-16
Also published as: WO2001059409A3; DE20180033U1; ATA1862000A; AT409043B; AU3141001A

Abstract

The invention relates to a position measuring system for a two-dimensional actuator (1) that moves substantially parallel to the axis within the running tread (2) of a stator according to the commands of a control. Said position measuring system comprises a scissor-type joint with arms (3 and 4) rotatably linked via a scissor joint (7). The extremities of said arms are fastened to the two-dimensional actuator (1) via a first rotation joint (5) in a point of reference used for reference and via a second rotation joint (6). Absolute or incremental rotary transducers (8 and 9) are mounted in two of the three rotation joints or scissor joints (5, 6 and 7), said rotary transducers measuring directly or indirectly the angle (14) between the arm (3) and a first reference line that runs parallel to one of the two directions of movement, and at the same time the angle (15) between the arm (4) and another reference line that runs parallel to the first reference line. The measured values are transmitted to an evaluation unit which calculates the position coordinates X6 and Y6 of the second rotation joint (6) on the two-dimensional actuator (1) in relation to the system of coordinates of the running tread (2) of the stator using the measured values and the lengths (a and b) of the arms (3 and 4) and the relative position of the first rotation joint (5).

Description

Position measuring system and positive guidance for a 2-coordinate actuator

The invention relates to a position measuring system and a positive guidance for a 2-coordinate actuator which moves within the running surface of a stator in accordance with the commands of a control essentially axially parallel.

Wing motors are 2-coordinate actuators that can move independently on two stator systems crossed at 90 degrees on the running surface of a stator in both axis directions X and Y and at the same time follow the respective control signals. You can describe any path and move to end positions, but the orientation of the surface motor always remains parallel to the axis and is referred to as the normal position. If there were to be a rotation out of the normal position, which exceeds the pole pitch in the order of magnitude, the purely frictional connection would be decoupled and the driving force would suddenly drop to zero, and the flat motor would become uncontrollable. This danger exists with asymmetrically attacking external forces. When carrying out purely translatory movements, the flat motor can lose steps due to overloading without having to decouple. A typical representative of this class of 2-coordinate actuators is described in US Pat. Nos. 3,376,578 A and 3,457,482 A, another in Japanese Patent JP 137018/85 and European Patent EP 207 353 AI. In the German patents DE 195 41 085 C2 and DE 196 31 106 AI as well as in the US patent US 4 890 241 A there are also comparable actuators. In order to ensure a controlled movement sequence in every phase of the movement, the position of the surface motor and its angular position must be measured continuously in order to ensure that a programmed path or end position is maintained using this position data supplied to a control system. There are essentially two types of measuring methods for the position of 2-coordinate actuators known. With small ner travel paths up to approx. 250 x 250mm, a contactless optical measuring system is used for each axis direction, e.g. a laser interferometer. The position values obtained in this way are absolute. The disadvantage is the high price and the limitation of the travel distances due to the fact that the reflectors have to be as wide as the travel of the axis perpendicular to the measuring direction. Another disadvantage is that the optical path must not be interrupted. The second method uses the pole grid as a material measure, the position of a sensor being measured magnetically or optically within a pole period. An example with optical measurement is described in US Pat. No. 5,126,648.

The position measurement within the pole period is much more precise with the aid of a Hall sensor. The disadvantages lie primarily in the sensitivity to inhomogeneities of the pole grid and in a different pole / groove ratio or in fluctuating groove depths. Since flat motors usually slide on air cushions, they can also fluctuating air cushion thicknesses have a falsifying effect on the measurement result. Inhomogeneities can result from contamination of the surface, lack of individual poles or joints in the soft iron sheet layer of the stator, into which the poles are incorporated. The most important disadvantage of all measuring methods that use the pole grid as a scale is that the position measurement values obtained are affected by the manufacturing tolerances of the pole grid, which leads to unsatisfactory absolute measured values, especially for dimensions with a length and width of several meters.

It is an object of the present invention to provide a measuring system which can also be used with very long travels and which measures the positions and angular positions of surface-mounted motors absolutely or incrementally, independently of the pole grid. For this purpose, a position measuring system according to the invention comprises a scissor-shaped joint with the arms rotatably connected via a scissor joint, the outer ends of which are fastened on the one hand via a first swivel joint in a reference point serving as a reference point and on the other hand via a second swivel joint on the 2-coordinate actuator, in two of the three rotary or scissor joints, absolute or incremental rotary encoders are mounted, which directly measure the angle between the arm and a first reference line running parallel to one of the two directions of movement and at the same time the angle between the arm and another reference line running parallel to the first reference line or measure indirectly and the measured values are transmitted to an evaluation unit, which from this and from the lengths of the arms and the relative position of the first swivel joint, the position coordinates X6 and Y6 of the second swivel joint on the 2-coordinate actuator based on the coordinate system of the tread of the stator is calculated. The measuring system according to the invention is therefore based on the principle of measuring arms with which workpieces and 3D models are measured and digitized. These consist of arms which are connected by hinges and strung together, with at least one swivel for each degree of freedom. Each swivel joint is equipped with an absolute or incremental encoder, which determines the angle of the two interconnected arms and outputs it as a digital or analog measured value to a processor which, based on the known arm lengths and the angle between the individual arms, determines the spatial distance between the one End point, which is fixed, and the other end point, which is provided with a measuring ball that touches the point to be measured.

In the case of the flat motor, which only moves in the plane, you can get by with two antennas and two rotary encoders. The two arms are connected to each other by a scissor joint, and the two other ends of the arms are each connected via a swivel joint on the one hand to a fixed point, which serves as a reference point, and on the other hand to the surface motor whose position is to be measured. The arm lengths are dimensioned so that the flat motor can reach any position within the travel range on the stator running surface. The lengths of the two arms are usefully the same size, and the two encoders mounted on the joints of the end points so as not to put unnecessary strain on the intermediate joint.

The difficulties associated with the known measuring systems described at the outset cannot arise with the position measuring system according to the invention, since this is based on a completely different, independent of the pole grid and without complex optical

Systems based functional principle.

In a development of the invention it can be provided that in all three rotary or

Scissor joints are mounted absolute or incremental encoders, which also the

Angle of rotation between an axis of the 2-coordinate actuator and its

Normal position and thus the position of the reference point of the 2-coordinate actuator can be determined.

A preferred embodiment of the invention can comprise a second scissor-shaped joint, consisting of the arms rotatably connected via a scissor joint, which is arranged offset from the first joint consisting of the arms, each joint being provided with two rotary encoders which rotate in any two directions - respectively.

Scissor joints of the respective scissor-shaped joint are mounted to independently of one another the position coordinates of the second rotary joints, or any two

Points that are at a defined distance from the second swivel joints of the 2-coordinate

Actuator, or to determine the angle of rotation of the 2-coordinate actuator based on the normal position.

It can thus be recognized that the actuator is already starting to rotate, so that it is possible to counteract such rotation immediately in order to reliably prevent decoupling of the actuator.

According to a further embodiment of the invention it can be provided that the

Reference point, in which the first swivel joint is located, is mounted on an auxiliary drive which is moved in parallel and in synchronism with one of the two axial directions, and the position of the

Auxiliary drive is measured along its axis of movement by a linear measuring system, so that the position values of the 2-coordinate actuator are in the two

Have the axial directions determined as described from the angles of rotation of the arms, and in the axial direction of the auxiliary drive, its position value, measured by the

Linear measuring system, must be added.

With long travel distances of the actuator, it would be necessary to train the arms relatively long. By providing an auxiliary drive with which the reference point at which the first swivel joint lies is also moved synchronously in a coordinate direction, excessively long arms can be avoided.

In a further embodiment of the invention, it can be provided that each of the two arms consists of two parallel legs which are rotatably connected to one another via scissor joints and whose second outer ends can be rotated via second swivel joints on the

Coordinate actuator and their first outer ends rotatable via first rotary joints a movable auxiliary drive or fixed fixed points, whereby there is a fixed connection between the scissor joints and consequently two movable parallelograms are formed, which have the effect that the 2-coordinate actuator can only move in parallel while maintaining its normal position and cannot twist and of which each parallelogram is provided with a rotary encoder which, as described, can clearly determine the position of the 2-coordinate actuator. When using a scissor-shaped joint constructed in this way, rotation of the actuator is excluded. The angle of rotation of the actuator can therefore not change, which is why it does not have to be detected. The number of rotary encoders required for position determination can thus be reduced. In this context it can be provided that the swivel joints lie on lines that are not parallel to the normal position but at an angle to it, consequently the scissor joints lie on lines that are not parallel to each other lying in the parallelogram plane, furthermore that the scissor joints lie on one common carrier plate are fixed. The second rotary joints can thus be moved as close as desired to the first rotary joints, ie the actuator as close as possible to the component on which the first rotary joints are fixed, that is to say to the auxiliary drive or to the edge of the stator surface. The stator surface can thus be used as far as possible as a traversing surface. 2-coordinate actuators are often used for machining workpieces, for which purpose corresponding machining tools are arranged on these actuators. It is often not sufficient to move the actuator only in two directions, rather the processing tool must also be moved normally to these two directions.

For this purpose, a linear drive is attached to the 2-coordinate actuator, the slide of which can be moved normally to the running surface. The processing tool is mounted on this slide and can thus be moved normally to the travel directions of the 2-coordinate actuator.

It is a further object of the present invention to provide a position measuring system for such a 2-coordinate actuator which can also be used with very long travels and which measures the positions and angular positions of flat motors independently of the pole grid, absolutely or incrementally.

According to the invention, this is achieved by means of a scissor-shaped joint with the arms rotatably connected via a double scissor joint, the outer ends of which, on the one hand, can be rotated via a first swivel joint in a reference point serving as a reference point and, on the other hand, are attached to the slide of the 2-coordinate actuator via a double swivel joint are, wherein the first joints of the double swivel joints pivot the arms parallel to the tread and the second joints of the double swivel joints allow the arm to swivel noraial to the tread, in two of the three first swivel or scissor joints and in at least one of the second joints the double Scissor or rotary joints absolute or incremental rotary encoders are mounted, which the angle between the arm and a first reference line running parallel to one of the two directions of movement and at the same time the angle between the arm and a further reference line running parallel to the first reference line and the Measure the included angle directly or indirectly between the arm and the tread plane and the measured values are transmitted to an evaluation unit, which uses these and from the lengths of the arms and the relative position of the first swivel joint to determine the position coordinates X6 and Y6 of the second swivel joint at the 2 coordinate Actuator calculated based on the coordinate system of the running surface of the stator. The scissor-shaped joint is connected here directly to the slide of the linear drive located on the 2-coordinate actuator, with which it can be used in addition to determining the position to supply energy to this slide or to the machining tool arranged on this slide. If the arms of the joint are designed as pipes, electrical lines, pressurized water or compressed air lines can be routed inside these pipes. The most interesting area of application for such a position measuring system is processing systems that work with a laser beam. It is known to generate the laser beam by means of a laser generator located outside the running surface and to feed it to a focusing device located on the 2-coordinate actuator via a mirror joint arm. The embodiment of the position measuring system according to the invention which has just been presented can be implemented most simply by installing the rotary encoders necessary for measuring the angles in this known and already existing mirror articulated arm. A separate joint that is added to this mirror joint arm can thus be saved.

In a further development of the invention it can be provided that absolute or incremental rotary encoders are mounted in all three first rotary or scissor joints, as a result of which the angle of rotation between an axis of the two-coordinate actuator and its normal position and thus the position of the reference point of the second Coordinate actuator can be determined.

In a further embodiment of the invention, a second scissor-shaped joint, consisting of the ants rotatably connected to one another via a double scissor joint, can be provided, which is arranged offset to the first joint consisting of the arms, each joint being provided with two rotary encoders which any two first or Scissor joints of the respective scissor-shaped joint are mounted, and rotary encoders are mounted in at least one of the second joints of the double scissor-type or rotary joints of each scissor-type joint, in order to independently control the position coordinates of the second rotary joints, or any two points that are in each other defined distance to the second swivel joints of the 2-coordinate actuator or determine the angle of rotation of the 2-coordinate actuator based on the normal position.

According to a preferred embodiment of the invention, it can be provided that the reference point, in which the first swivel joint is located, is mounted on an auxiliary drive which is moved in parallel and synchronously with one of the two axial directions, and the position of the auxiliary drive along its movement axis by means of a linear measuring system is measured so that the position values of the 2-coordinate actuator in the two axis directions can be determined from the angles of rotation of the arms as described, and in the axis direction of the auxiliary drive, its position value, measured by the linear measuring system, must be added.

In a further development of the invention it can be provided that each of the two Anne consists of two parallel legs, each of which is rotatably connected to one another via double scissor joints and the second outer ends of which are each rotatable on the slide of the 2-coordinate actuator and via second double pivot joints the first outer ends of which are rotatably attached to a movable auxiliary drive or fixed fixed points via first swivel joints, a fixed connection being established between the double scissor joints and consequently two movable parallelograms being formed, which have the effect that the 2-coordinate actuator is only parallel while maintaining its normal position and can not twist and of which each parallelogram is provided with at least one rotary encoder arranged in one of the first rotary or scissor joints, and in at least one of the second joints of the double scissor or rotary joints a rotary encoder it is provided which D as described, the position of the 2-coordinate actuator can be clearly determined.

When using a scissor-shaped joint constructed in this way, rotation of the actuator is excluded. The angle of rotation of the actuator can therefore not change, which is why it does not have to be detected. The number of rotary encoders required for position determination can thus be reduced. Another object of the invention is to provide a positive guidance for a 2-coordinate actuator which moves within the running surface of a stator in accordance with the commands of a control substantially axially parallel, with which any rotation of this actuator can be prevented. A compulsory guide according to the invention comprises a scissor-like joint comprising rotatably connected Aime, which two arms each from two parallel

Legs exist, which are rotatably connected to one another via scissor-type joints, the second outer ends of which are rotatable on the 2-coordinate actuator via second rotary joints and the first outer ends of which are rotatable on a movable one via first rotary joints

Auxiliary drive or fixed fixed points, which are preferably outside of the tread, are fixed, the two scissor joints are firmly connected.

Such positive guidance is of simple construction and is therefore particularly reliable.

In a development of the forced operation according to the invention it can be provided that

Swivel joints lie on lines that are not parallel to the normal position but at an angle to it, consequently the scissor joints lie on lines that are not parallel to one another in the parallelogram plane, furthermore that the scissor joints are on a common one

Carrier plate are fixed.

With this, the second swivel joints can be arbitrarily close to the first swivel joints, i.e. the

Actuator can be moved as close as possible to the component on which the first rotary joints are fixed, i.e. to the auxiliary drive or to the edges of the stator surface.

The stator surface can thus be used as far as possible as a traversing surface.

Another object of the invention is to provide a positive guide for a 2-

Coordinate actuator that is located within the tread of a stator according to the

Commands of a control moved essentially axially parallel and on which a drive, in particular a linear drive, is fixed, the carriage of which can be moved normally to the running surface, with which any rotation of this actuator can be prevented.

For this purpose, a positive guidance according to the invention comprises a scissor-shaped joint comprising arms which are rotatably connected to one another, which two arms each consist of two parallel arms

There are legs that are rotatably connected to each other via double scissor joints, the second outer ends of which can be rotated via double swivel joints on the carriage of the 2-

Coordinate actuator and their first outer ends are rotatably fixed via first swivel joints on a movable auxiliary drive or at fixed fixed points, which are preferably located outside the running surface, the two double scissor joints being firmly connected to one another.

The invention is explained below with reference to the accompanying drawings. It shows:

1 shows a first embodiment of the invention schematically in plan with the flat motor 1 lying in the normal position; 2 shows the embodiment of Fig.l in the same representation when rotated relative to the

Normally lying flat motor 1;

Fig. 3 shows a second embodiment of the invention schematically in plan;

4 shows a third embodiment of the invention, in which two scissor-shaped joints are provided, schematically in plan;

5 shows a further embodiment essentially corresponding to that of FIG. 4, in which the two scissor-shaped joints are fixed on an auxiliary drive, schematically in plan;

6 and 7 each show a fifth embodiment, in which the between the legs

21,22 and 21 ', 22' lying swivel joints 7,7 'are firmly connected to each other, schematically in plan;

8 shows a flat motor including the associated stator, equipped with a position measuring system according to the invention in oblique outline;

9 shows a flat motor including the associated stator in an oblique view, a laser beam focusing device 41 being fixed on the flat motor, which can be moved normally to the plane of the stator by means of a drive 46 and which uses a laser beam 40

Mirror arm is fed;

10 shows the plant shown in Figure 9 in elevation;

Fig.l 1 the system shown in Figures 9 and 10 schematically in plan and

12 shows a system corresponding to the embodiment of FIGS. 9-11, in which the two

Arms 3a, 4a each consist of two parallel legs 21,21 'and 22,22', in plan and

Fig. 13 shows the system of Fig. 9-1 schematically in plan with straight, i.e. tubes 3a, 4a oriented in one and the same direction.

In the embodiment of the invention shown in FIG. 1, 1 denotes a 2-coordinate

Actuator (hereinafter also referred to as "surface motor") and with 2 the running surface of the

Stator, on which the surface motor 1 is movable, called.

The position measuring system according to the invention comprises a scissor-shaped joint which is formed from two arms 3, 4 which are rotatably connected to one another by a scissor joint 7.

The other two ends of the Anne 3, 4, which are spaced apart from the scissors joint 7, are connected via a first swivel joint 5 with a fixed point, which serves as a reference point, and via a second

Swivel 6 connected to the surface motor 1, the position of which is to be measured.

These arms 3, 4 have lengths a and b, which are preferably chosen to be of equal length. The arm lengths are dimensioned so that the flat motor 1 can reach any position within the travel range on the stator running surface.

In two of the three rotary or scissor joints 5, 6 or 7 are absolute or incremental

Encoders 8 and 9 mounted. In order not to unnecessarily stress the scissor joint 7, so as shown in the drawings, the rotary encoders 8 and 9 are preferably mounted on the rotary joints 5, 6.

The coordinates X and Y of the reference point 11 of the surface motor 1 are also shown in FIGS. 1 and 2. A and B denote the offset of the reference point at which the first swivel joint 5 lies with respect to the zero point of the coordinate system, and Ax, By denote the offset of the second swivel joint 6 with respect to the reference point 11 of the surface motor 1.

The surface motor 1 pulls the measuring machine comprising the scissors-shaped joint and for each position on the running surface 2 there is a clearly assignable pair of angles 14 and 15. The coordinates of the second swivel joint X6 = (a.cosα + b.) Result from simple trigonometric relationships. cosß) + A and Y6 = (a.sinα-b.sinß) + B, the offset distances A, B of the reference point, in which the first swivel joint 5 lies, with correct sign, ie in the position shown in Fig.l each with a negative sign.

The coordinates of the reference point 11 can be calculated using the following formulas: X = (a.cosα + b.cosß) + Cx and Y = (a.sinα-b.sinß) + Cy, where Cx is the correct addition of A + ax and Cy are formed from B + By.

The angles 14 (α) and 15 (β) are determined absolutely or incrementally with the help of the rotary encoders 8 and 9. As can be seen from FIGS. 1 and 2, the angle 14 (α) lies between the ann 3 and a first reference line, which runs parallel to the first direction of movement (X direction) of the actuator 1. The angle 15 (β) lies between the arm 4 and a further reference line which runs parallel to the first reference line of the angle 14 (α) and thus also in the X direction. It would also be possible to have both reference lines run in the other direction of movement, namely in the Y direction.

The angle 15 (ß) must be related to the normal position of the surface motor 1. This normal position is obtained by energizing the flat motor 1 in a known reference position, expediently at the position X6 = 0 and Y6 = 0, so that it can be aligned exactly parallel to the pole grooves. The associated angle 15 (β) can then be calculated as the reference angle 15 from the known position data. The reference angle value supplied by the encoder 9 is detected or set to zero. This reference angle 15 must be added to all other values or difference values supplied by the rotary encoder 9 with respect to the reference angle value with the correct sign in order to obtain the corresponding angle 15 (β). The same procedure is to be used for the angle 14 (α), ie that in the selected reference position X6 = 0 and Y6 = 0 the angle 14 (α) is to be calculated as the reference angle 14 and the angle value supplied by the encoder 8 is to be set to zero. The further procedure is in accordance with what has been said for the angle 15. All the calculations mentioned are carried out by an evaluation unit, not shown in the drawings, to which the angle values detected by the rotary encoders 8, 9 are transmitted. When using only two rotary encoders 8 and 9, if the second rotary encoder 9, as shown in FIGS. 1 and 2, is mounted in the rotary joint 6 lying on the surface motor 1, the position of the surface motor 1 can only be correctly determined if the surface motor is located 1 is in its normal position, shown in FIG. 1, or remains in this normal position during its traversing movements,

If it is to be expected that the surface motor 1 rotates with respect to this normal position, its position can no longer be correctly determined, because rotations of the surface motor 1 also lead to a change in the angle between the arm 4 and the surface motor 1. The angle 15 (ß ) can therefore no longer be correctly calculated from the angle between the arm 4 and the flat motor 1 supplied by the rotary encoder 9. If, on the other hand, the second rotary encoder 9 is mounted on the scissor joint 7, the angle between Ann 3 and arm 4, which is then supplied by the rotary encoder 9, can always, i.e. regardless of possible twists of the surface motor 1, the angle 15 (ß) can be calculated.

If there is a risk of the surface motor 1 rotating, because it is either very large in size or is subjected to very asymmetrical loads, simple trigonometric relationships can be achieved by using a third rotary encoder 24, which is mounted in the scissors joint 7 as shown in FIG the angle 17 of the twist angle 16 of the surface motor 1 can be calculated. Using this angle of rotation 16, the position of the swivel joint 6 or the reference point 11 of the surface motor 1 can now be calculated even if the surface motor 1 is rotated relative to its normal position, as shown in FIG. The purpose is to detect the beginning of rotation of the surface motor 1 in the beginning and to counteract it before decoupling takes place. Countermeasures are only possible, however, if the motor elements on the different sides can be controlled like independent axes, similar to a portal drive.

In order to avoid excessively long arms, which would inevitably arise in the case of long travels, the fixed reference point, in which the first swivel joint 5 lies, can be moved synchronously with the rotary encoder 8 in a coordinate direction according to FIG. 3, with the same control for the Movement of the synchronous axes is responsible. Although in principle any linear auxiliary drive 10 with a mechanical guide can be used for this movement, it is sensible to use a single-axis air-bearing linear motor that slides on the same stator.

In order to be able to use as much expensive running surface 2 as possible for the surface movement, the side surface of the stator can be provided with a one-dimensional pole system, and the linear auxiliary drive 10 can be designed as an angle motor, as shown in FIG. 3 shows the most general case, according to which any drive 10 as an auxiliary drive with its own guidance moves the reference point at which the first swivel joint 5 is located synchronously. This auxiliary drive 10 comes completely outside the stator surface 2. The position measurement of the drive 10 along the X axis is carried out with a length measuring system consisting of the ruler 25 and the measuring head 26, which can work optically, inductively or according to another principle. The coordinates X and Y of the surface motor 1 result from the measured value of the linear system 25, 26 and the angles 14 and 15 of the rotary encoders 8 and 9, ie the X position values of the auxiliary drive 10 and the 2-coordinate actuator 1 in relation to the measuring machine are to be added. A possible deviation .DELTA.X of the X positions of the drive 1 from the drive 10 is also detected, as is expressed by the offset of the second swivel joint 6 to 6 "(cf. dashed line in FIG. 3). To determine the twist angle 16 of the surface motor 1, a third rotary encoder 24 can be used again.

In particular in the case of flat motors 1 with large dimensions or elongated shape, it can be useful or necessary to determine the angle of rotation 16 by measuring the position of two points lying at opposite ends of the flat motor 1. Fig. 4 shows such an arrangement with a second scissor-shaped joint with the arms 12 and 13 and the rotary joints 18, 19 and the scissor joint 20. Two rotary encoders 8, 9 and 38, 39 are used per scissor-shaped joint, which in any Drehbzw. Scissor joints 5,6,7; 18,19,20 are mounted.

With this, the position coordinates of the second rotary joints 6 and 19 or any two points that are at a defined distance from the second rotary joints 6 and 19 of the 2-coordinate actuator 1 can be determined independently of one another. From these, the angle of rotation 16 of the 2-coordinate actuator 1 can also be calculated based on the normal position.

An additional scissor-shaped joint formed from the arms 12 and 13 and comprising two rotary encoders 38, 39 thus has the same function as a third rotary encoder 24 on the scissor joint formed from the arms 3 and 4, namely it serves for detection in the same way as this third rotary encoder 24 of the angle of rotation 16 of the flat motor 1. The advantage over the arrangement of only one scissor-shaped joint with three rotary encoders 8, 9, 24 is that a second identical scissor-shaped joint can be added if necessary.

5 shows the arrangement in which two scissor-shaped joints can also be used in the case of the auxiliary drive 10.

In order to prevent twisting at all, the flat motor 1 can be forced to feel parallel, in that the two scissor-shaped joints by a Cross connection 23 between the scissor joints 7 and 7 'are formed as a parallelogram, as shown in Fig.6.

In this embodiment, each of the two Anne 3 and 4 consists of two parallel ones

Legs 21, 21 'and 22, 22', which are rotatably connected to one another via scissor joints 7, 7 '. The second outer ends of the legs 22, 22 'are rotatably attached to the 2-coordinate actuator 1 via second swivel joints 6, 6'. The first outer ends of the

Legs 21, 21 'can be rotated on a linear auxiliary drive via the first swivel joints 5,5'

10 set.

There is a fixed connection 23 between the scissor joints 7, 7 '. The two, on this

Formed away from the legs 21,21 'and 22,22' and the fixed connection 23

Parallelograms mean that the 2-coordinate actuator 1 is only parallel under

Maintain its normal position and cannot twist.

Such a cross connection 23 can also be used when the fixed

Reference points in which the first swivel joints 5,5 'are not on a linear one

Auxiliary drive 10, but - as shown in Figure 4 - are held immovably.

When such a cross connection 23 is used, the surface motor is twisted

1 excluded. Each pair of rotary encoders 8, 9 and 38, 39 provided in FIGS. 5, 6 and 7 thus delivers the same result. It follows from this that - in deviation from the representations of the

Fig. 5, 6 and 7- no more four encoders 8,9,38,39 must be provided, but only a pair of these encoders 8,9 or 38,39, that is, only one for each parallelogram

Encoder.

By evaluating the angles detected by these two rotary encoders 8, 9 and 38, 39, the position of the 2-coordinate actuator can be - as in the embodiment according to FIG

1 can be clearly determined.

FIG. 7 shows an embodiment in which the legs 21, 21 'and 22.22' are not rotatably connected to one another via a pair of scissors joints 7, 7 ', but in each case via two scissor joints 27, 27' and 28.28 '. All four scissor joints 27, 27 'and 28, 28' are firmly connected to one another, which is achieved in that these four scissor joints 27, 27 'and 28, 28' are fixed on a common support plate 23.

The rotary joints 5,5 ', 6,6' and their corresponding scissor joints 27,27 'and 28,28' are arranged at an angle to each other. The swivel joints 5,5 'and 6,6' each lie on a line which does not run parallel to the normal position, but rather includes an acute angle with this normal position of the surface motor 1.

It follows from this that even those lines on which the scissor joints 27, 27 'and 28, 28' lie do not run parallel but include an acute angle with one another. This configuration has the advantage that the motors 1 and 10 can come as close as desired, that is to say the stator surface 2 is used as far as possible as a travel surface. In a departure from the embodiment shown in FIG. 7, the lines on which the swivel joints 5,5 'and 6,6' and the scissor joints 27,27 'and 28,28' lie can also run parallel to the normal position of the surface motor 1.

The construction of the two arms 3, 4 just discussed can also be used when the position of the actuator 1 does not need to be determined, i.e. in applications where only a positive guidance of the actuator 1 is achieved and a rotation of the actuator 1 is to be prevented.

In terms of design, such a positive guidance largely corresponds to the embodiments in FIG. 6 or 7; only the rotary encoders 8, 9 or 38, 39 (or the evaluation unit, which calculates the position of the actuator 1 from the rotary encoder data) are omitted.

Fig. 8 shows a typical overhead application with a laterally grooved stator, as is particularly advantageous for laser processing. The drive 10 is an air-bearing, angular linear motor 10 which uses both the crossed pole system of the running surface of the stator 2 and the linear pole system of the side surface of the stator 2. The position of the linear motor 10 along its direction of movement is measured by the linear measuring system 25, 26. The two arms 3 and 4 connect the motors 1 and 10, and the rotary encoders 8 and 9 are integrated in the rotary joints of the drives 1 and 10. Since the drive 10 is designed as a linear motor, the arrangement is simplified by the omission of a separate guide and a separate motor drive.

When machining workpieces with a laser beam 40, the laser generator required for its generation is very often not arranged directly on the surface motor 1. Rather, the laser generator is located outside of the running surface 2, with which it can be made structurally larger and thus can generate a laser beam 40 with a higher energy content. The laser beam 40 is fed to the surface motor 1 or a focusing device 41 arranged thereon via a mirror.

Such a system is shown in an oblique view in FIG. Mounted on the auxiliary drive 10 is a mirror-articulated arm known per se, which comprises two pipes 3a, 4a which are connected to one another in an articulated manner. At the entrance end of the tube 3a, at the exit end of the tube 4a and in the joint area connecting these two tubes 3a, 4a, mirrors 44, 45; 44a, 45a; 44b, 44c, 45b, via which the laser beam 40 is fed to the focusing device 41.

The first end of the first pipe 3a is rotatably connected to the auxiliary motor 10 via a first swivel joint 5, just as the second end of the second pipe 4a is rotatably connected to the surface motor 1 via a swivel joint 6. The two tubes 3a, 4a are rotatably connected to one another via a scissor joint 7. Such a mirror articulated arm can be used to implement the present invention by installing rotary encoders 8, 9 in at least two of the three rotary or scissor joints. The arms 3 and 4 of the measuring machine according to the invention are here formed by the tubes 3a, 4a of the mirror articulated arm.

A tool, such as e.g. Drills, milling cutters, laser beam exit openings or the like, with which a workpiece is machined. Since contours to be machined into the workpiece very often not only run parallel to the running surface 2, but also extend normally to this running surface 2, it is necessary to move the tool sitting on the surface motor 1 normally to the running surface 2. For this purpose, drives are arranged on the flat motor 1, by means of which the tool can be moved accordingly. In the exemplary embodiment in FIGS. 9-1 1, this drive is formed by a linear drive 46, on the slide 46a of which can be moved normally to the running surface 2, the tool is mounted. However, this is only to be understood as an example; the invention is not restricted to such linear drives 46. In particular, the slide 46a does not have to be displaceable exactly normal to the tread 2 of the stator, and drives which move their slide 46a obliquely relative to the tread 2 are also conceivable.

Such drives, in particular linear drives 46, can be designed, in particular for mechanical processing such as drilling and milling, or can be defined on the flat motor 1 in such a way that displacements of this linear drive 46 have no effect on the position of the flat motor 1 or cause no swiveling of the Guide pipes 3a, 4a. This is achieved simply in that the tube 4a is not fixed with the slide 46a, but directly on the surface motor 1.

Even if the machining tool is a laser beam 40 generated outside of the surface motor 1, which is fed via a mirror joint to the focusing device 41 seated on the surface motor 1, the end of the tube 4a on the output side could only be pivoted parallel to the tread 2, pivots running normally to the tread 2 of the tube 4a, however, be prevented.

The mirrors 44a, 45a located at the end of the tube 4a on the output side can be oriented such that the laser beam 40 emerges from the mirror articulated arm running normal to the running surface 2.

If the focusing device 41 is arranged in alignment over the laser beam exit opening, the distance between the laser exit opening located on the mirror joint arm and the entry opening on the focusing device 41 changes non-normally to the tread 2 when the focusing device 41 moves. However, the laser beam 40 nevertheless becomes the focusing device 41 supplied, regardless of the current distance from the running surface 2. Movements of the focusing device 41 by moving the slide 46a in the direction normal to the running surface 2 do not affect the position of the surface motor 1 or lead to any pivoting of the tubes 3a, 4a , In the n embodiment shown in FIGS. 9-11, on the other hand, it is provided that the output-side end of the tube 4a is not connected directly to the surface motor 1, but to the focusing device 41, which can be moved normally to the running surface 2 by means of the linear drive 46 , In order to enable such displacements, a double joint 7.70 and 6.60 must be provided both between the two tubes 3a, 4a and between the outlet end of the tube 4a and the focusing device 41 (cf. their schematic representation in Fig. l 1).

The first joints 7, 6 (which are also present in the previously described embodiments of the measuring machine according to the invention) allow the pipes 3 a, 4 a to be pivoted parallel to the running surface 2.

The second articulations 70, 60 of the double articulations 7, 70; 6, 60 allow the pipe 4a to be pivoted, as indicated by the arrow 47 in FIG. 10, normal to the running surface 2, which pivoting results when the linear drive 46 is moved. So that a movement of the slide 46a of the linear drive 46 is actually implemented entirely in a displacement of the focusing device 41 and does not lead to a pivoting of the double joint 7.70 normal to the running surface 2, is in the area of the two tubes 3a, 4a connecting one another Double joint 7.70 a holder is provided which keeps the distance of this double joint 7.70 from the tread 2 constant.

In the exemplary embodiment in FIGS. 9-11, this holder is formed by a magnetic disk 48 which is connected to the double joint 7.70 and is held by the magnetic field of the running surface 2. There is an air film between the tread surface and the disk 48, on which the disk 48 slides. The disc 48 is not driven separately, but is pulled by the tubes 3a, 4a when the surface motor 1 moves. So that the disc 48 is held even in the plane of the tread 2 when the surface motor 1 is moved so close to the edge of the tread 2 that the disc 48 already comes to lie outside the tread 2, a plate is on the tread 2 49 made of magnetizable material, for example an iron plate (see Fig. 9).

The holder can be of any design and other than a magnetic disk 48. If the tread 2 lies under the mirror articulated arm (the arrangement of FIGS. 9-11 is rotated by 180 °), the holder is pressed against the tread 2 by the weight of the mirror articulated arm and can be formed by a non-magnetic slide shoe.

If the swivel joint 5 is made so strong that it reliably prevents pivoting of the tube 3a normal to the running surface 2, the mounting of the double scissor joint 7.70 can be omitted at all. A movement of the linear drive 46, as already shown, results in a pivoting of the tube 4a normal to the running surface 2. Due to the given, unchangeable length of the tube 4a and the fact that both the surface motor 1 and the auxiliary motor 10 are held in their positions, these pivotings result in displacements of the double joint 7.70 running parallel to the tread plane , so that the pipes 3a, 4a swivel parallel to the tread plane and ultimately to changes in the angles 14 (α) and 15 (ß) and the angle 51 between the pipe 4a and the plane of the tread 2.

A position measuring system, which is only equipped with rotary encoders 8, 9, which are mounted in the rotary joints 5, 6, 7 for the purpose of detecting the angles 14 (α) and 15 (β), can therefore no longer correctly detect the position of the surface motor 1.

An additional rotary encoder 50 is therefore provided, with which the angle 51 enclosed between the tube 4a and the tread plane 2 is detected. This angle 51 can be seen undistorted in FIG. 10. The tubes 3a, 4a are stretched here in the manner shown in Fig. 13, i.e. oriented in one and the same direction. If all three angles 14 (α) and 15 (β) and 51 are taken into account, the position of the surface motor 1 can be clearly determined despite displacements of the slide 46a. The rotary encoder 50, which detects the angle 51, can optionally be arranged in the second joint 60 of the double rotary joint 6, 60 attached to the focusing device 41 or in the second joint 70 of the double scissor joint 7, 70 located between the two tubes 3a, 4a. It would be conceivable to provide a rotary encoder 50 in each of these second joints 60, 70, but these would deliver matching results. The angle values detected by the rotary encoders 8, 9 and 50 are again transmitted to an evaluation unit, which calculates the position coordinates X6N6 of the second rotary joint 6 based on the coordinate system of the tread 2 from these angle values and the known lengths of the tubes 3a, 4a.

The reference point at which the first swivel joint 5 lies is mounted in the embodiment of FIGS. 9-1 1 on an auxiliary drive 10 which is moved in parallel and synchronously with one of the two axial directions. Analogously to the embodiment of FIG. 3, the current position of the auxiliary drive 10 must be taken into account here when calculating the surface-area motor position, which is measured by a linear system as in FIG. 3. This auxiliary drive 10 is not mandatory to be provided when using a mirror joint arm, rather it is also possible here — analogously to FIG. 1 — to keep the first swivel joint 5 immovable relative to the running surface 2.

Furthermore, analogously to FIG. 3, rotary encoders 8, 9, 24 can be provided in all three rotary or scissor joints 5, 6 and 7, which allow pivoting of the tubes 3a, 4a parallel to the running surface 2, to determine the position of the surface motor 1 can also be determined if it can twist relative to its normal position. 9 and 10, for the sake of clarity, the focusing device 41 is fixed immovably on the slide 46a of the surface motor 1. However, this is not absolutely necessary. Rather, the focusing device 41 can be pivoted on the slide 46a as desired and the laser beam 40 can be fed to it from the output-side end of the mirror joint arm fixed on the slide 46a via a further mirror system, for example via a further mirror joint arm. The focusing device 41 can thus be moved as desired relative to the slide 46a without these movements changing the position of the surface motor 1.

The embodiment of the invention shown in FIGS. 9-11 is mainly used for mirror articulated arms, which is why reference was made to such a mirror articulated arm for the purpose of their explanation. However, this is not to be understood as restrictive; rather, with articulated arms 3, 4 or any machining tools attached to surface motor 1, double joints 7.70, 6.60 can be provided, and second arm 4 on slide 46a of a linear drive located on surface motor 1 46 are attached.

In FIGS. 9 and 10, the direction of displacement of the linear drive 46 always runs exactly 90 ° to the tread plane, which alignment is, however, not absolutely necessary. Rather, the direction of displacement can include any angle to the tread 2. At such angles, which differ from 90 ° to the tread plane, the displacement movement of the slide 46a also has a movement component running parallel to the tread plane and parallel to it. If the known angle, which is included between the tread plane and the direction of displacement, is taken into account when calculating the position of the surface motor 1, the surface motor position can also be correctly calculated with such displacement directions that differ from 90 ° to the tread.

If, in the context of this application, one speaks of a slide 46a which is shifted normally to the tread 2, this means that the movement carried out by the slide 46a has a component which runs normally to the tread plane. It is not important whether the carriage movement has only such a component or additionally also a component running parallel to the tread plane.

As already stated above, it is not absolutely necessary to arrange a linear drive 46 on the flat motor 1, rather a drive of any design can be used for the tool movement. In the context of this application, the term “slide 46a” is therefore not to be understood solely as a slide 46a of a linear drive 46, but rather the movable part of any drive. Analogous to FIGS. 4, 5, a second scissor-shaped joint can be provided, which is constructed identically to the first joint, that is to say also comprises two arms that are rotatably connected to one another via a double scissor joint and that via a double swivel joint to the Carriage 46a of the linear drive 46 arranged on the flat motor 1 is connected.

This second scissor-shaped joint, like the first one, has rotary encoders 8 and 9 in two of its three rotary joints 5, 6, 7, which allow pivoting of the arms 3, 4 parallel to the running surface 2. Furthermore, a rotary encoder 50 is also provided in at least one of the second joints 70, 60 of the double scissor or rotary joints 7.70, 6.60.

The two scissor-shaped joints are arranged offset from one another as in FIGS. With these two joints, the positions of two mutually objectionable points on the surface motor 1 can be measured, with which the angle of rotation 16 of the surface motor 1 can be determined in relation to the normal position.

Analogously to FIGS. 6, 7, in a system just discussed, in which the second arm 4a is connected to the first arm 3a via a double scissor joint 7.70 or to the carriage 46a via a double swivel joint 6.60 is to be provided that the surface motor 1 is forcibly guided in parallel.

For this purpose, as shown in FIG. 12, each of the two arms 3a and 4a is formed from two parallel legs 21, 21 'and 22.22', each of which has a double scissor joint 7.70; 7 ^' , 70 ^{' are} rotatably connected to one another.

The second outer ends of this double joint are each via second double swivel joints 6.60; 6 ', 60' rotatably attached to the slide 46a of the 2-coordinate actuator 1. The first outer ends are rotatably attached to the movable auxiliary drive 10 via first swivel joints 5,5 ^' . If such an auxiliary drive 10 is not present, the first outer ends — as in FIG. 4 — are fixed at fixed fixed points. The double scissor joints 7, 70 of the first legs 21, 22 are connected to the double scissor joints 7'70 'of the second legs 21', 22 'via a fixed connection 23. This fixed connection 23 is designed such that each of the four scissor joints 7, 70, 7 ^' , 70' located there can rotate freely, but that the distance between these joints is always kept constant.

The legs 21, 21 ^' and 22, 22' thus form two movable parallelograms, which have the effect that the 2-coordinate actuator 1 can only move in parallel while maintaining its normal position and cannot twist. To determine the position of the surface motor 1, rotary encoders 8 and 9 are again provided, which are located in two of the first rotary or scissor joints 5, 6 and 7; 5 ', 6' and 7 'are arranged. Analogous to FIGS. 6, 7, a further pair of rotary encoders 38, 39 could be provided, but due to the positive guidance of the surface motor 1, it must deliver the same results as the first pair 8, 9. In addition to the rotary encoders 8, 9, at least one of the second joints 70, 60; 70 ', 60' of the double scissor or rotary joints 7.70; 7'70 ';6.60; 6 ', 60', a rotary encoder 50 is provided with which the swivel angle 51 of the arm 4a relative to the plane of the running surface 2 is detected.

The construction of the two arms 3a, 4a just discussed can also be used if the position of the surface motor 1 does not need to be determined, i.e. in applications where only a positive guidance of the surface motor 1 is achieved and a rotation of the surface motor 1 is to be prevented.

In terms of design, such a positive guidance largely corresponds to the embodiments in FIG. 12; only the rotary encoders 8, 9, 38, 39 and 50 (or the evaluation unit, which calculates the position of the surface motor 1 from the rotary encoder data) are omitted.

claims:

Claims

PATENT CLAIMS

1. Position measuring system for a 2-coordinate actuator (1) which moves within the running surface (2) of a stator in accordance with the commands of a control essentially axially parallel, characterized by a scissor-shaped joint with the arms rotatably connected via a scissor joint (7) 3 and 4), the outer ends of which are rotatably fastened on the one hand via a first swivel joint (5) to a reference point serving as a reference point and on the other hand via a second swivel joint (6) on the 2-coordinate actuator (1), with two of the three swivel or , Scissor joints (5, 6 and 7) absolute or incremental rotary encoders (8 and 9) are mounted, which encompass the angle (14) between the ann (3) and a first reference line running parallel to one of the two directions of movement and at the same time the angle (15 ) measure directly or indirectly between the arm (4) and a further reference line running parallel to the first reference line and the measured values are transmitted to an evaluation unit, which uses these and from the lengths (a and b) of the arms (3 and 4) and the relative position of the first swivel joint (5), the position coordinates X6 and Y6 of the second swivel joint (6) on the 2-coordinate actuator (1) are calculated based on the coordinate system of the running surface (2) of the stator.

2. Position measuring system according to claim 1, characterized in that absolute or incremental rotary encoders (8, 9 and 24) are mounted in all three rotary or scissor joints (5, 6 and 7), whereby the angle of rotation (16 or 17) between an axis of the 2-coordinate actuator (1) and its normal position and thus the position of the reference point (11) of the 2-coordinate actuator (1) can be determined.

3. Position measuring system according to claim 1 or 2, characterized by a second scissor-shaped joint, consisting of the arms (12 and 13) rotatably connected to one another via a scissor joint (20), offset from the first joint consisting of the arms (3 and 4) is arranged, each joint being provided with two rotary encoders (8 and 9 or 38 and 39) which are mounted in any two rotary or scissor joints (5, 6, 7; 18, 19, 20) of the respective scissor-shaped joint to independently of one another the position coordinates of the second rotary joints (6 and 19), or any two points that are at a defined distance from the second rotary joints (6 and 19) of the 2-coordinate actuator (1), or the angle of rotation (16) of the 2-coordinate actuator (1) based on the normal position.

4. Position measuring system according to claim 1, 2 or 3, characterized in that the reference point, in which the first swivel joint (5) lies, is mounted on an auxiliary drive (10) which is moved in parallel and synchronously with one of the two axial directions, and the position of the auxiliary drive (10) along its movement axis is measured by a linear measuring system (25, 26), so that the position values of the 2-coordinate actuator (1) in the two axis directions are as described from the angles of rotation of the arms (3 and 4) have determined, and in the axial direction of the auxiliary drive (10) whose position value, measured by the linear measuring system (25, 26), must be added.

5. Position measuring system according to claim 1, 2 or 4, characterized in that each of the two arms consists of two parallel legs (21,21 'and 22,22'), the scissor joints (7,7 'and 27,27' and 28,28 ') are rotatably connected to one another and their second outer ends are rotatable via second rotary joints (6,6') on the 2-coordinate actuator (1) and their first outer ends are rotatable via first rotary joints (5,5 ') a movable auxiliary drive (10) or fixed fixed points, wherein between the scissor joints (7,7 'or 27,27' and 28,28 ') there is a fixed connection (23) and consequently two movable parallelograms are formed which cause that the 2-coordinate actuator (1) can only move in parallel while maintaining its normal position and cannot twist and of which each parallelogram is provided with a rotary encoder (8 and 9) which, as described, the position of the 2-coordinate - Actuator (1) can be clearly determined NEN.

6. Position measuring system according to claim 5, characterized in that the rotary joints (5,5 'and 6,6') lie on lines which are not parallel to the normal position but at an angle to it, consequently the scissor joints (27,27 'and 28 , 28 ') lie on lines which are not parallel to one another in the parallelogram plane, furthermore that the scissor joints (27, 27' and 28, 28 ') are fixed on a common carrier plate (23).

7. Position measuring system for a 2-coordinate actuator (1) which moves within the running surface (2) of a stator in accordance with the commands of a control substantially axially parallel and on which a drive, in particular a linear drive (46), is fixed, the carriage (46a) can be moved normally to the tread (2), characterized by a scissor-shaped hinge with the ants (3 and 4 or 3a and 4a) rotatably connected via a double scissor hinge (7,70), the outer ends of which, on the one hand, are connected via a first Swivel joint (5) rotatable in a Reference point serving the reference point and, on the other hand, are fastened to the slide (46a) of the 2-coordinate actuator (1) via a double swivel joint (6, 60), the first joints (7, 6) of the double swivel joints (7, 70; 6.60) a pivoting of the arms (3 and 4 or 3a and 4a) parallel to the tread (2) and the second joints (70.60) of the double swivel joints (7.70; 6.60) a pivoting of the Allow arms (4 or 4a) normal to the running surface 2, the double-scissor- or double-scissor- or in two of the first three rotating or scissor-type joints (5, 6 and 7) and in at least one of - Rotary joints (7.70; 6.60) absolute or incremental rotary encoders (8, 9 and 50) are mounted, which the angle (14) between the Ann (3 and 3a) and a first, parallel to one of the two directions of movement extending reference line and at the same time the angle (15) between the arm (4 or 4a) and a further reference line running parallel to the first reference line and between the arm (4 or 4a) and the tread plane included angle (51) directly or indirectly and the measured values are transmitted to an evaluation unit, which from this and from the lengths (a and b) of the arms (3 and 4 or 3a and 4a) and the relative position of the first swivel joint (5) calculates the position coordinates X6 and Y6 of the second swivel joint (6) on the 2-coordinate actuator (1) based on the coordinate system of the running surface (2) of the stator.

8. Position measuring system according to claim 7, characterized in that absolute or incremental rotary encoders (8, 9 and 24) are mounted in all three first rotary or scissor joints (5, 6 and 7), whereby the angle of rotation (16 and 17 ) between an axis of the 2-coordinate actuator (1) and its normal position and thus the position of the reference point (11) of the 2-coordinate actuator (1) can be determined.

9. Position measuring system according to claim 7 or 8, characterized by a second scissor-shaped joint, consisting of the rotatably connected arms via a double scissor joint, the first, from the arms (3 and 4 or 3 a and 4a) existing joint offset is arranged, each joint being provided with two rotary encoders (8 and 9) which are mounted in any two first rotary or scissor joints (5, 6, 7) of the respective scissor-shaped joint, and in each case at least one of the second joints ( 70, 60) of the double-scissor or rotary joints (7.70; 6.60) of each scissor-shaped joint, rotary encoder (50), in order to independently determine the position coordinates of the second rotary joints (6), or any two points, which are at a defined distance from the second rotary joints (6) of the 2-coordinate actuator (1), or Determine the angle of rotation (16) of the 2- <coordinate actuator (1) based on the normal position.

10. Position measuring system according to claim 7, 8 or 9, characterized in that the reference point, in which the first swivel joint (5) lies, is mounted on an auxiliary drive (10) which is moved in parallel and synchronously with one of the two axial directions, and the position of the auxiliary drive (10) along its movement axis is measured by a linear measuring system (25, 26), so that the position values of the 2 - coordinate actuator (1) in the two axis directions are as described from the angles of rotation of the arms (3 and 4 or 3 a and 4 a) can be determined, and in the axial direction of the auxiliary drive (10) whose position value, measured by the linear measuring system (25, 26), must be added.

11. Position measuring system according to claim 7, 8 or 10, characterized in that each of the two arms (3 and 4 or 3a and 4a) consists of two parallel legs (21,21 'and 22,22'), each via double Scissor joints (7,70; 7 ', 70') are rotatably connected to one another and their second outer ends are each rotatable on the slide (46a) of the 2-coordinate actuator via second double swivel joints (6,60; 6 ', 60') (1) and their first outer ends via first swivel joints (5,5 ') are rotatably attached to a movable auxiliary drive (10) or at fixed fixed points, with a fixed one between the double scissor joints (7,70; 7' 70 ') Connection (23) exists and consequently two movable parallelograms are formed, which have the effect that the 2-coordinate actuator (1) can only move in parallel while maintaining its normal position and cannot twist, and each parallelogram with at least one, in one the first rotary or scissor joints (5, 6 and 7; 5 ', 6' and 7 ') arranged rotary encoder (8 and 9) and in at least one of the second joints (70, 60; 70 ', 60') of the double scissor or rotary joints (7.70; 7 ^' 70 ^' ; 6.60; 6 ^' , 60') a rotary encoder (50) is provided, which rotary encoders (8.9, 50) can clearly determine the position of the 2-coordinate actuator (1) as described.

12. Forced guidance for a 2-coordinate actuator (1) which moves within the running surface (2) of a stator in accordance with the commands of a control essentially axially parallel, characterized by a scissor-shaped joint comprising arms (3, 4) which are rotatably connected to one another, which two arms (3, 4) each consist of two parallel legs (21, 21 'and 22, 22') which are rotatably connected to one another via scissor joints (7, 7 'and 28, 28' and 27, 27 ') are, the second outer ends via second swivel joints (6,6 ') rotatable on the 2-coordinate actuator (1) and the first outer ends via first swivel joints (5,5 ') rotatably on a movable auxiliary drive (10) or at fixed fixed points, which are preferably outside of the tread (2), the two scissor joints (7,7' or 28,28 'or 27th , 27 ') are firmly connected.

13. positive guidance according to claim 12, characterized in that the rotary joints (5,5 'and 6,6') lie on lines which are not parallel to the normal position but at an angle to this, consequently the scissor joints (27,27 'and 28th , 28 ') lie on lines which are not parallel to one another in the parallelogram plane, furthermore that the scissor joints (27, 27' and 28, 28 ') are fixed on a common carrier plate (23).

14. Forced operation for a 2-coordinate actuator (1), which moves within the running surface (2) of a stator in accordance with the commands of a control essentially axially parallel and on which a drive, in particular a linear drive (46), is fixed, the Carriage (46a) can be moved normally to the running surface (2), characterized by a scissor-shaped joint comprising arms (3, 4 or 3a, 4a) which are rotatably connected to one another, which two arms (3, 4 or 3a, 4a) each consist of two parallel legs (21,21 'and 22,22') exist which are rotatably connected to each other via double scissor joints (7,70; 7 ', 70'), the second outer ends of which are connected via double swivel joints (6,60; 6 , 60 ') rotatable on the slide (46a) of the 2-coordinate actuator (1) and its first outer ends via first swivel joints (5,5') rotatable on a movable auxiliary drive (10) or at fixed fixed points, which are preferably outside the Tread (2) are set, the at the double scissor joints (7,70; 7 ', 70') are firmly connected.