EP2917000A1

EP2917000A1 - Method and machine system for positioning two movable units in a relative position to each other

Info

Publication number: EP2917000A1
Application number: EP13815678.1A
Authority: EP
Inventors: Walter Leopold STICHT; Johann Kritzinger; Christian Mersnik; Reinhard Schlager
Original assignee: Stiwa Holding GmbH
Current assignee: Stiwa Holding GmbH
Priority date: 2012-11-08
Filing date: 2013-11-07
Publication date: 2015-09-16
Also published as: HK1212294A1; CN104918755B; AT513697A1; WO2014071434A1; CN104918755A; US20150286211A1; AT513697B1

Abstract

The invention relates to a method for positioning a first movable unit (2) of a machine system (1) and a second movable unit (5) of the machine system (1) in a definable relative position to each other. For this purpose, the first movable unit (2) is moved to a first position (13) within a first travel space (4) with the aid of a first measuring system. The second movable unit (5) is moved to a second position (14) within a second travel space with the aid of a second measuring system (9). The first movable unit (2) and/or the second movable unit (5) is moved to the predetermined relative position to each other with the aid of a third measuring system (11, 15..25). The invention further relates to a machine system (1) for carrying out said method.

Description

Method and machine system for positioning two movable units in a relative position to each other

The invention relates to a method for positioning a first movable unit of a machine system and a second movable unit of the machine system in a predeterminable relative position to each other, wherein

the first movable unit is moved by means of a first measuring system to a first position within a first movement space, and

the second movable unit is moved by means of a second measuring system to a second position within a second movement space.

Furthermore, the invention relates to a machine system comprising

a first movable unit, which is movable with the aid of at least one first drive in a first movement space,

a first of the first movable unit associated measuring system, with the aid of which the first movable unit can be positioned at any predetermined position in the first movement space,

a second movable unit, which is movable with the aid of at least one second drive in a second movement space, wherein the first movement space and the second movement space have an overlapping area, and

a second of the second movable unit associated measuring system, with the aid of which the second movable unit can be positioned at any predetermined position in the second movement space.

A method and a machine system of the type mentioned are basically known, for example in the form of a machine tool, whose machining head designed as a first movable unit and whose tool carriers designed as second movable units move into a tool change position. The machining head is thereby positioned by means of a first measuring system, which includes, for example, incremental or absolute encoders on the axes of motion. The tool carriers may for example be arranged on a chain which is positioned by means of a second measuring system, which may also comprise incremental or absolute encoders. Because the processing Boter and the tool change system are arranged on a common frame or stand on their placement in a predetermined position to each other, can be approached by specifying a first position in the first measuring system and a second position in the second measuring a certain relative position of the machining head to the tool carrier to a tool change perform.

Unfortunately, in practice, it can be seen that the position of a machining robot and a tool changing system with each other may change over time. Reasons for this are temperature-induced deformations or plastic deformation of the components involved as well as aging phenomena of the measuring systems and sensor drift. The deviations can become so strong that the tool or the machining head is damaged during a tool change or a tool change can not be performed. For this reason, such machine systems or their measuring systems are calibrated at regular intervals after installation or during operation.

"Calibration" generally refers to a measuring process for determining and documenting the deviation of a measuring device or a material measure to a reference device or a reference standard of measurement, whereby the reference device or reference dimension is also called "normal". The determined deviation is taken into account in the subsequent use of the measuring device for correcting the displayed values.

As a result of the calibration of the first and the second measuring system, the relative position of the machining head relative to the tool carrier determined by the first and second positions coincides again with the desired relative position.

The disadvantage is that the calibration process, which makes it necessary to measure the machine system, is very complex. In addition, a certain accuracy between two calibration operations can not be guaranteed.

Another disadvantage of the known machine system is that the entire first and second measuring system must have a relatively high accuracy, which is based on the required accuracy of the relative position to be adopted. Especially for large tool changing magazines can cause considerable costs for the correct positioning of the tool carrier necessary measuring system.

In addition, the achievable accuracy of the relative position due to error addition is well below the accuracy of the first and the second measurement system. If, for example, the first measuring system has an accuracy / resolution of +/- 0.1 mm and the second measuring system has an accuracy / resolution of +/- 0.2 mm, then for the given relative position with an accuracy / resolution of +/- 0.3 mm can be achieved. An object of the present invention is therefore to provide an improved method and an improved machine system for positioning two movable units in a relative position to each other. In particular, calibration processes should be avoided or their spacing should at least be extended, and the accuracy / resolution of the relative position increased, wherein the accuracy / resolution of the first and / or second Meßsys- system does not need to be increased or even reduced.

The object of the invention is achieved by a method of the type mentioned, in which

the first movable unit and / or the second movable unit is / are moved by means of a third measuring system into said predetermined relative position.

The object of the invention is further achieved with a machine system of the type mentioned, additionally comprising

a third measuring system, which is adapted to determine a relative position between the first movable unit and the second movable unit.

The achievable for the relative position accuracy can be significantly increased by the inclusion of a third measuring system. The running in the machine system steps are thus more accurate and reliable.

A preferred variant of the method is characterized in that the first position and the second position lie within a detection range of the third measuring system. A preferred machine system is characterized in that the detection range of the third measuring system is in said overlapping area.

In this way, the achievable for the relative position accuracy (only) depends on the third measuring system. If, for example, the first to third measuring systems have an accuracy / resolution of +/- 0.1 mm, an accuracy / resolution of +/- 0.1 mm can be achieved for the given relative position. An error addition does not lead to a reduced accuracy / resolution of +/- 0.2 mm as in the prior art. In addition, it is noted that "resolution" generally indicates the smallest apparent difference between two readings, while "accuracy" generally indicates the difference between measured size and true size. A high resolution is therefore not necessarily an indication of high accuracy and vice versa. In general, the accuracy may be expressed as the difference between the measured quantity and the true size or the ratio of the two (for example, relative accuracy in percent).

The proposed measures calibration can also be avoided or their distance can be at least extended without the achievable accuracy for the relative position suffers, especially between two Kalibriervorgängen. However, a calibration process of the first and / or second measuring device may be necessary, for example, when the first and / or the second position are no longer within the measuring range of the third measuring device. A calibration of the third measuring device may be necessary if the third measuring device is no longer sufficiently accurate. In the proposed method and the proposed machine system, the observance of an absolute measure of the first and / or second measuring device for the achievement of a certain relative position between the first and the second movable unit is actually irrelevant. As a rule, it is sufficient if the relative position or the relative position finally reached by the first and second position lies in the measuring range of the third measuring system "somewhere." The use of reference standards, as is the case with a calibration process, is not necessary. Further advantageous embodiments and modifications of the invention will become apparent from the dependent claims and from the description in conjunction with the figures.

It is advantageous if

- At least one of the first movable unit associated with the first drive for

Approaching the first position is coupled to the first measuring system,

at least one of the second movable unit associated second drive for starting the second position is coupled to the second measuring system and

the first drive and / or second drive for starting the predetermined relative position is / are coupled to the third measuring system, in particular exclusively with the third measuring system.

Likewise, a machine system is advantageous, comprising means for coupling

the first drive with the third measuring system alternatively / in addition to the first measuring system and / or

- The second drive with the third measuring system alternatively / in addition to the second measuring system.

In this variant of the method, the first and the second position are therefore approached with the aid of the first and the second measuring system. From there, the predetermined relative position is approached by means of the third measuring system. For this purpose, it is possible that correction values for the first and / or second measuring system are determined with the third measuring system and the corrected first and / or second position is approached with the aid of the first and / or the second measuring system. A drive control of the machine system advantageously does not need to be modified for this purpose since only adjusted setpoint values for the first and / or second measuring system are predetermined with the aid of the third measuring system. It is also conceivable that the drives of the machine system are decoupled from the first and / or second measuring system and instead coupled to the third measuring system.

As a result, the position control is then carried out directly via the third measuring system. Finally, mixed forms of the two mentioned methods are possible. For example, both the values determined by the first / second measuring system and the values determined by the third measuring system can be used for the position control. Under certain circumstances, the positioning accuracy compared to a method in which only the first / second measuring system or only the third measuring system is used, can be substantially improved. As an example, it is again assumed that all measuring systems have a resolution of +/- 0, 1 mm. If the "scales" of the first and second measuring systems and of the third measuring system are shifted from one another, in particular by 0.05 mm, then the accuracy / resolution can be increased to + / by simultaneously using the measured values of the first / second measuring system and the third measuring system. - 0.05 mm can be increased.

It is particularly advantageous if the relative position of the first movable unit to the second movable unit is measured directly by the third measuring system. As a result, the deviation of the actual relative position from the desired relative position is at most as great as the accuracy / resolution of the third measuring system. If the accuracy / resolution is, for example, +/- 0.1 mm, then the relative position can be determined with +/- 0.1 mm accuracy / resolution.

But it is also advantageous if the relative position of the first movable unit to the second movable unit by measuring the position of the first movable unit to a reference point and by measuring the position of the second movable unit to this reference point by the third measuring system and by subsequent subtraction of the two Positions is determined. It is advantageous that the third measuring system can be fixedly mounted on a frame. This makes it easy to protect against dirt and damage. If necessary, a possible error addition should be considered. If the accuracy / resolution of the third measuring device is again, for example, +/- 0.1 mm, then the relative position can be determined with +/- 0.2 mm accuracy / resolution.

Moreover, it is particularly advantageous if the measured values of the first and / or second measuring system are stored when the predetermined relative position is reached as a future first and / or second position. The first and second positions are therefore not necessarily constant. Instead, the first and / or the second position is continuously readjusted, so that the relative position reached by the first and second position is successively approximated or tracked successively to the desired desired relative position or the actual relative position determined by the third measuring system. In this way, it is ensured that the first and the second position do not over the course of time due to temperature-induced or plastic deformation of the components involved as well as aging phenomena and sensor drift of the first and / or second measuring system from the measuring It should be noted at this point that this process is not a calibration of the first and / or second measuring device, since the achievement of a certain relative position of the first and second movable units relative to each other is not It is imperative that it is bound to a precisely working or calibrated first and second measuring system, and that a correct relative position can also be achieved with a "wrong" first and second position.

A preferred embodiment is characterized in that the first position and / or the second position lies outside the detection range of the third measuring system. Such a constellation is particularly suitable for machine systems in which a plurality of second movable units, in particular workpiece carriers, are coupled together, e.g. in the form of a transport chain. By detecting the position of a workpiece carrier can also be deduced the position of the other workpiece carrier. From a deviation of the actual position from a desired position of the detected workpiece carrier at a given time it can be concluded that other workpiece carriers in the same composite have a corresponding deviation from the desired position. This information can be used to achieve the predetermined relative position anyway and beyond with high accuracy. An advantage of this variant is also that the third measuring system is not arranged in the common working area of the movable units and takes up space there.

A preferred embodiment is characterized in that the first movable unit before reaching the first position and / or the second movable unit is detected by the third measuring system before reaching the second position. Given a predetermined and therefore known movement sequence of the movable unit (for example workpiece carrier of a transport chain), a later deviation between the actual position and the desired position can be avoided in advance.

A preferred embodiment is characterized in that the detection of the first movable unit before reaching the first position and / or the second movable unit before reaching the second position by the third measuring system takes place at a predetermined time with respect to a reference point. This measure increases the accuracy and is particularly advantageous for continuously moving units. A preferred embodiment is characterized in that the third measuring system detects the position and / or the size and / or the shape of at least one of the movable units and / or detects the arrangement or type of a workpiece or tool on at least one of the movable units. Thus, not only is it possible to detect the movable unit (eg workpiece carrier of a transport chain) as such, but also the position and / or orientation of a workpiece or tool on the movable unit. Since the machine system is aligned to the machining of the workpiece, the information about the workpiece in the determination of the relative position of great importance. Depending on the position or orientation of the workpiece, therefore, at least one drive can already be subjected to a corresponding manipulated variable, possibly even before the workpiece carrier enters the second position or working position.

In the presented machine system, it is advantageous if the resolution and / or accuracy of the third measuring system is lower than that of the first and / or second measuring system. If the accuracy / resolution of the first and second measuring device is sufficient for realizing a certain accuracy / resolution of the relative position between the first and the second mobile unit, the third measuring system can without disadvantage have a lower accuracy / resolution than the first and the second measuring system. This is especially true when the third measuring system provides only correction values for the first and / or the second measuring system and the final position of the first and second movable units is approached with the aid of the first and second measuring devices. If, for example, the first measuring system has an accuracy / resolution of +/- 0.1 mm and the second measuring system has an accuracy / resolution of +/- 0.2 mm, an accuracy / resolution of +/- 0 can be achieved for the given relative position , 3 mm can be achieved if only the first and the second measuring system are used for position control. For the third measuring system, an accuracy / resolution of +/- 0.3 mm is therefore sufficient in principle in this case. It is also particularly advantageous if the resolution and / or accuracy of the third measuring system is higher than that of the first measuring system and / or the second measuring system and / or total resolution / Summengenauigkeit the first and second measuring system. In this way, the relative position can be determined with higher accuracy than with the first and second measuring system would be possible. The reason for this, in turn, is the error addition already mentioned above. If, for example, the first measuring system has an accuracy / resolution of +/- 0.1 mm and the second measuring system has an accuracy / resolution of +/- 0.2 mm, then for the given relative position an accuracy / resolution of better than + / - 0.3 mm can be achieved if the third measuring system is used for the position control and the resolution / accuracy of the third measuring system is higher than the sum resolution / sum quantity inaccuracy of the first and second measuring system, in this case better than +/- 0, 3 mm. More preferably, the resolution / accuracy of the third measuring system is higher than that of the second measuring system (ie better than +/- 0.2 mm) or even higher than that of the first measuring system (ie better than +/- 0.1 mm) , This variant is therefore particularly useful if the position control of the first and / or second movable unit using the third measuring system.

It is furthermore particularly advantageous if the first and / or second measuring system are designed as a discontinuous measuring system and the third measuring system as a continuous measuring system.

In a "discontinuous" measuring system, physical quantities are recorded in the form of a step function (digital), for example a length measuring system or an angle measuring system that works on the basis of a barcode.When the width of a bar is known, only the number of passes has to be used For example, such discontinuous length measuring systems or angle measuring systems can be designed as incremental encoders or absolute value encoders For example, by assigning a unique code, incremental encoders require an additional reference position from which the length increments can be counted physical size in a "continuous" measuring system continuously, that is infinitely (analog) detected. Of course, a continuous acquisition of a physical quantity does not exclude a subsequent digitization of the acquired measured value, but the detection as such takes place. nitely. However, the acquisition of a measured value can never be finer than permitted by physical laws, in particular quantum mechanics.

The mentioned embodiment of the machine system now combines the advantages of both measuring systems in an advantageous form. While the first and / or second measuring system is designed as a discontinuous and thus very robust measuring system, the third measuring system is designed as a continuous and thus usually very accurate measuring system.

In a further favorable embodiment of the machine system, the third measuring system comprises at least one of the group Hall sensor, Wirbelstromabstandsmeßsensor, Magnetoinduktiven distance sensor, capacitive distance sensor, laser triangulation sensor, position Sensitive Device, camera distance sensor.

Some types of distance measuring sensors or position sensors are known from the prior art, of which some illustrative examples are enumerated above. In general, the invention is not limited to these specifically mentioned types, but can also be realized with other measuring principles.

If a Hall sensor flows through a current and is brought into a perpendicular magnetic field, it delivers an output voltage that is proportional to the product of magnetic field strength and current. A Hall sensor, unlike electrodynamic sensors, provides a signal even when the magnetic field is constant. Since the field strength of a magnet decreases with increasing distance, the distance of the Hall sensor from the magnet can be determined via the field strength. The third measuring system of the machine system can thus have a Hall sensor and at least one magnet, wherein

a) the Hall sensor on the first movable unit and a first magnet on the second movable unit is arranged or

b) the Hall sensor is arranged at a fixed point (for example machine frame, machine foundation), a first magnet is arranged on the first movable unit and a second magnet of the second movable unit is arranged.

In case a), the relative position of the first movable unit to the second mobile unit can thus be measured directly, in case b) it is obtained by subtracting the two measured positions. In case b), the Hall sensor can be advantageously mounted on a stationary machine part, whereas the movable units are equipped with the little prone to interference magnets. An eddy current sensor has a resonant circuit, which often comprises a substantially inductive measuring head and a line which acts essentially as a capacitance, and is damped by a metallic object. The active resonant circuit generates an alternating magnetic field whose field lines emerge from the measuring head and generates eddy currents in the metallic object, which result in negative losses. These losses are indirectly proportional to the distance of the metallic object from the measuring head. The third measuring system of the machine system may thus comprise an eddy current sensor and at least one metallic object, wherein

a) the eddy current sensor is disposed on the first movable unit and a first metallic object is disposed on the second movable unit or

b) the eddy current sensor is disposed at a fixed point (e.g., machine frame, machine foundation), a first metallic object is disposed on the first movable unit, and a second metallic object is disposed on the second movable unit. In the case a), the relative position of the first moving unit to the second moving unit can thus again be measured directly, in case b) it is determined by subtracting the two measured positions. In case b), the eddy current sensor can be advantageously mounted on a stationary machine part, whereas the movable units are equipped with the little interference-prone metallic objects.

Magnetoinductive distance sensors combine the evaluation of the magnetic field strength with the eddy current principle. Advantageously, thus largely linear characteristics can be achieved over a wide detection range. The cases a) and b) cited for the Hall sensor and the eddy current sensor can also be applied correspondingly in the magnetoinductive distance sensor. Capacitive sensors are based on measuring the capacitance or capacitance change of two mutually displaceable electrodes. The capacitance or capacity change is a measure of the distance between the electrodes. In general, the normal distance of the electrodes or their transverse distance (change of the effective area, resp. tive of the cutting area of the two electrodes) are modified for this purpose. The third measuring system of the machine system can thus have a capacitive distance sensor, wherein

a) a first electrode on the first movable unit and a second electrode on the second movable unit is arranged or

b) a first electrode on the first movable unit, a second electrode on the second movable unit, and a third electrode at a fixed point (e.g., machine frame, machine foundation).

In the case a), the relative position of the first moving unit to the second moving unit can thus again be measured directly, in case b) it is determined by subtracting the two measured positions.

In the distance measurement by means of laser triangulation, a laser beam is emitted to a test object, where it strikes a reflector at a certain angle and is reflected to a receiver in accordance with the law of reflection. Based on the position at which the reflected laser beam impinges on the receiver, the distance between transmitter / receiver and DUT can be calculated. The third measuring system of the machine system can thus comprise a laser triangulation sensor and at least one reflector gate, wherein

a) the transmitter and the receiver on the first mobile unit and a first

Reflector is disposed on the second movable unit or

b) the transmitter and the receiver at a fixed point (eg machine frame, machine foundation) are arranged, a first reflector on the first movable unit and a second reflector object on the second movable unit is arranged, wherein the laser beam from the transmitter via both reflectors on the Or c) the transmitter is arranged on the first movable unit, the receiver is arranged on a fixed point and a first reflector is arranged on the second movable unit or

d) the receiver on the first movable unit, the transmitter is arranged at a fixed point and a first reflector on the second movable unit.

In cases a), c) and d), the relative position of the first moving unit to the second moving unit can again be measured directly or at least the presence of a certain relative position can be detected; in case b) it is again subtracted the two measured positions determined. The movable units can in turn be equipped with little interference-prone reflectors.

In the above context, the use of a "Position Sensitive Device" is an advantage: A "Position Sensitive Device" or "Position Sensitive Detector" (PSD) is an optical position sensor (OPS) that can measure the one- or two-dimensional position of a light spot For example, a large-area photodiode (lateral diode, "position-sensitive diode") can be used for this purpose, in which a photocurrent arises in the region of the exposure which, depending on the light position, flows off in a specific ratio over the contacts located at the edges. From the streams, the location of the exposure can be calculated one or two-dimensionally. Alternatively, the PSD may also be a CCD or CMOS camera, in particular a line camera. In a further favorable embodiment of the machine system, the third measuring system comprises at least one light source and at least one photosensitive element, wherein the relative position between the first movable unit and the second movable unit by evaluation of a shadow on the at least one photosensitive element is determined, which is caused by the light emitted by the at least one light source and the first movable unit and / or the second movable unit.

This embodiment can therefore be regarded as a special form of a "Position Sensitive Device" or "Position Sensitive Detector" (PSD). However, the light beam is not bundled here but deliberately emitted in a wedge shape. Without disturbing objects in the light beam, the photosensitive element, which is designed, for example, as a transversal diode, CCD or CMOS camera, is illuminated substantially uniformly or at least in a defined manner. If an object is introduced into the light beam, this causes a shadow on the photosensitive element, which provides information about the position in which the said object is in relation to the light source or the photosensitive element.

In such a measuring system of the machine system can

a) the transmitter and the receiver on the first mobile unit and a first shading object to be arranged on the second movable unit or

b) the transmitter and the receiver are arranged at a fixed point (for example machine frame, machine foundation), whereas a first shading object on the first moving unit and a second shading object on the second moving unit are arranged, or

c) the transmitter is arranged on the first movable unit, the receiver on a fixed point and a first shading object on the second movable unit or

d) the receiver is arranged on the first movable unit, the transmitter on a fixed point and a first shading object on the second movable unit.

In this embodiment, the relative position of the first movable unit to the second movable unit in all cases a) to d) measured directly or at least the presence of a certain relative position can be detected. In the case b), to create an unambiguous assignment of movable unit to the generated shadow, the shading objects may have different shapes or have a different size. For example, if the first shading object generates a larger shadow than the first object, then the association of detected shadow with the corresponding movable unit can be determined by the size of the shadow. It is also advantageous if the first movable unit of the machine system is designed as the head of a robot and the second movable unit of the machine system as a workpiece carrier or tool carrier. This is an arrangement in which the above-mentioned problem underlying the invention frequently results and / or particularly comes to light. In particular, this is the case when, for example, moving units from different manufacturers are combined with one another. For example, a commercial industrial robot from one manufacturer can be combined with a custom workpiece or tool transport system. Positioning errors and problems due to different responsibilities are virtually inevitable. By providing the third measuring system, however, these disadvantages can be overcome. Plant engineering is therefore more flexible overall.

It is also favorable if several workpiece carriers or tool carriers are connected to one another in an annular manner, in particular connected directly to one another, attached to a chain or attached to a rope. The advantages of the presented method or of the measures presented are particularly important in this embodiment, since the chain or the rope to which the workpiece carriers or tool carriers are fastened can stretch over time. As a result, in particular, the values measured by the second measuring system no longer correspond to the original conditions, as a result of which the actual relative position between the head of the robot and a workpiece carrier / tool carrier deviates from the desired relative position without further measures. By providing the third measuring system this is no longer the case.

Finally, it is favorable if the workpiece carriers or tool carriers are designed as self-propelled units, in particular as rail-bound units. Again, the advantages of the presented method or the measures presented come particularly to bear, since self-propelled units, even if they are rail-guided, are generally more difficult to position than, for example, via a serial or parallel kinematics driven moving workpiece carrier or tool carrier. By providing the third measuring system, a relative position between robot head and workpiece carrier.

A preferred embodiment is characterized in that the first position and / or the second position lies outside the detection range of the third measuring system.

Thereby, e.g. the first movable unit before reaching the first position and / or the second movable unit are detected before reaching the second position by the third measuring system. A preferred embodiment is characterized in that third measuring system for detecting the position and / or the size and / or the shape of at least one of the movable units and / or the arrangement or type of a workpiece or tool is formed on at least one of the movable units. A preferred embodiment is characterized in that the second movable

Unit is designed as a workpiece carrier or tool carrier and that the workpiece carrier or tool carrier is part of a circulating transport chain, which comprises a plurality of workpiece carriers or tool carriers arranged one behind the other. In this type of transport sy stem the workpiece carriers are coupled in a composite, so that when the position of a carrier and the position of the other carrier can be deduced.

A preferred embodiment is characterized in that the transport chain has a leading, upper strand and a returning, lower strand and that the third measuring system is positioned such that at least a portion of the upper strand, preferably an end region of the upper strand, within the detection range of the third measuring system is located. The upper strand is usually tighter than the lower strand, so that the position or orientation is accurate when the upper strand is detected. In addition, the workstations are located along the upper line. The distance between the third measuring system and the individual workstations is therefore lower.

A preferred embodiment is characterized in that the third measuring system is arranged on the first movable unit or on the second movable unit. This enables a particularly reliable determination of the type and arrangement of a workpiece, e.g. on the workpiece carrier, which is independent of factors that are related to the movement of the movable unit.

A preferred embodiment is characterized in that the machine system is a production plant for producing an assembly of several parts. Here, the principle according to the invention is particularly advantageous, since the highest precision is required for uniting the individual components. The manufacturing plant may e.g. consist of several successively arranged workstations, each comprising a first movable unit in the form of a manipulation device (robot, gripper, soldering or welding station, etc.). The second moving unit is a transport chain of workpiece carriers, which conveys the workpieces through the individual work stations.

A preferred embodiment is characterized in that

at least one of the first movable unit associated first drive for starting the first position is coupled to the first measuring system,

at least one of the second movable unit associated second drive for starting the second position is coupled to the second measuring system and the first drive and / or second drive for starting the predetermined relative position is / are coupled to the third measuring system.

This allows optimal achievement of the predetermined relative position between the movable units.

It should be noted at this point that the various embodiments of the machine system as well as the resulting advantages can be applied analogously to the method for its operation and vice versa.

For a better understanding of the invention, this will be explained in more detail with reference to the following figures. Show it:

1 shows a schematically illustrated machine system with a movable robot head, a movable workpiece carrier and a camera measuring system;

Fig. 2 is an exemplary image captured by the camera measuring system;

Fig. 3 is a third measuring system in the form of a Hall sensor in combination with a

magnet;

4 shows a third measuring system in the form of a Hall sensor in combination with two magnets;

5 shows a third measuring system based on the laser triangulation;

Fig. 6 is a third measuring system in which a shadow on a photosensitive

Element is used to determine the relative position between the first and second movable unit;

Fig. 7 as Fig. 6 only with two shading objects; an embodiment of the invention with a circulating transport chain; Fig. 9 shows a further embodiment of the invention and

Fig. 10 shows an embodiment in which the third measuring system is arranged on the movable unit.

By way of introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numerals or the same component names, wherein the disclosures contained in the entire description can be mutatis mutandis to the same parts with the same reference numerals or component names. Also, the location information chosen in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to the new situation mutatis mutandis when a change in position. Furthermore, individual features or combinations of features from the illustrated and described different embodiments may represent for themselves, inventive or inventive solutions.

All statements on ranges of values in the description of the present invention should be understood to include any and all sub-ranges thereof, e.g. is the statement 1 to 10 to be understood that all sub-areas, starting from the lower limit 1 and the upper limit 10 are included, ie. all subregions begin with a lower limit of 1 or greater and end at an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.

1 shows a schematically represented machine system 1 with a first movable unit, which in this example is designed as the head 2 of a robot 3. The head 2, which is equipped here with a gripper, is movable by means of at least one first drive in a first, here hemispherical movement space 4. With the aid of a first, the first movable unit 3 associated measuring system, the first movable unit 2 can be positioned in a known manner at any predetermined position in the first movement space 4. Specifically, in the robot 3 designed as a multi-axis industrial robot, the first measuring system comprises a plurality of incremental or absolute encoders which measure the angles of the individual arm segments relative to one another. Thus, the position of the head 2 can be determined. Furthermore, the machine system 1 comprises a second movable unit, which in this example is designed as a workpiece carrier 5. Several workpiece carriers 5 are annularly connected to each other via a chain 6 and run on two rails arranged elevated 7. The workpiece carrier 5 are movable by means of a second drive 8 in a second, here annularly shaped movement space. With the aid of a second, the second movable unit 5 associated measuring system, which is formed in this example as a rotary encoder 9, the second movable unit 5 can be positioned at any predetermined position in the second movement space. On one of the workpiece carriers 5, a workpiece 10 is arranged in this example.

In addition, the machine system 1 comprises a third measuring system 11 whose detection area 12 lies in an overlapping area of the first movement space 4 and the second movement space and which is adapted to a relative position between the first movable unit (robot head) 2 and the second movable unit (workpiece carrier ) 5. The third measuring system is formed in this example as a camera measuring system 11

FIG. 2 shows an exemplary image acquired by the camera measuring system 11. Therein, the robot head 2 can be seen, whose first reference point arranged in the gripper lies at a first position 13. Furthermore, the workpiece carrier 5 can be seen with the workpiece 10 arranged thereon. An arranged on the workpiece carrier 5 second reference point is located at a second position 14. Starting from the second reference point, the target relative position of the first reference point is shown in broken lines. If possible, the robot head 2 and the workpiece carrier 5 are thus brought into the relative position shown in dashed lines to each other. For this purpose, the robot head 2 can be moved slightly to the bottom right. Alternatively, of course, it is also conceivable that the robot head 2 are moved only down and the workpiece carrier 5 to the left. Any combinations are conceivable here. When the predetermined relative position is reached, the robot head 2 executes predefined work on the workpiece 10. Thus, the method for positioning a first movable unit (robot head) 2 of a machine system 1 and a second movable unit (workpiece carrier) 5 of the machine system 1 in a predeterminable relative position to one another comprises the steps:

Moving the robot head 2 to a first position 13 within a first movement space 4 by means of a first measuring system,

Moving the workpiece carrier 5 to a second position 14 within a second movement space by means of a second measuring system 9, wherein the first position 13 and the second position 14 within a detection range 12 of a third measuring system (camera) are 11 and

- Moving the robot head 2 and / or the workpiece carrier 5 using the camera measuring system 11 in the said predetermined relative position.

There are several options for this. For example, the first drives of the robot 3 can be coupled to the first measuring system for approaching the first position 13,

the second drive 8 for starting the second position 14 are coupled to the second measuring system 9 and

the first drives and / or the second drive 8 for starting the predetermined relative position are coupled to the camera measuring system 11, in particular exclusively with the camera measuring system 11.

The machine system 1 comprises means for coupling

the first drives with the camera measuring system 11 alternatively / in addition to the first measuring system and / or

the second drive 8 with the camera measuring system 11 alternatively / in addition to the second measuring system. 9

On the one hand, it is now possible for correction values for the first measuring system and / or second measuring system 9 to be determined with the camera measuring system 11 and for the corrected first position 13 and / or second position 14 with the aid of the first measuring system and / or the second measuring system 9 is approached. A drive control of the machine system advantageously does not need to be modified for this purpose, since with the aid of the camera measuring system 11 only adjusted nominal values for the first measuring system and / or second measuring system 9 are predetermined. In general, the resolution and / or accuracy of the camera measuring system 11 can be be less than that of the first measuring system and / or second measuring system 9, since the robot head 2 and the workpiece carrier 5 are not positioned more accurately than the sum resolution / Summengenauigkeit the first measuring system and / or second measuring system 9 allow. If, for example, the first measuring system has an accuracy / resolution of +/- 0.1 mm and the second measuring system 9 has an accuracy / resolution of +/- 0.2 mm, an accuracy / resolution of +/- can be set for the given relative position. 0.3 mm can be achieved. For the camera measuring system 1 in this case therefore an accuracy / resolution of +/- 0.3 mm in principle sufficient. It is also conceivable that the first drives and / or the second drive 8 of the machine system 1 are decoupled from the first measuring system and / or second measuring system 9 and instead coupled to the camera measuring system 11. The resolution and / or accuracy of the camera measuring system 11 is then advantageously higher than that of the first measuring system and / or the second measuring system 9 and / or sum resolution / Summengenauigkeit the first measuring system and second measuring system 9. The achievable accuracy / resolution of the relative position depends in this case only on the accuracy / resolution of the camera measuring system 11. With the above-mentioned values for the first measuring system and / or the second measuring system 9, the accuracy / resolution of the camera measuring system 11 is preferably better than +/- 0.3 mm. More preferably, the resolution / accuracy of the camera measuring system 1 is l higher than that of the second measuring system 9 (ie better than +/- 0.2 mm) or even higher than that of the first measuring system (ie better than +/- 0, 1 mm).

Finally, mixed forms of the two mentioned methods are possible. For example, both the values determined by the first / second measuring system 9 and the values determined by the camera measuring system 11 can be used for the position regulation. Under certain circumstances, the positioning accuracy can be substantially improved compared to a method in which only the first / second measuring system 9 or only the camera measuring system 11 is used. As an example, it is again assumed that all measuring systems have an accuracy / resolution of +/- 0.1 mm. If the "scales" of the first / z-wide measuring system 9 and the camera measuring system 11 are shifted from each other, in particular by 0.05 mm, the accuracy / resolution by a simultaneous use of Measured values of the first / second measuring system 9 and the camera measuring system 11 are increased to +/- 0.05 mm.

In general, the relative position of the robot head 2 to the workpiece carrier 5 can be measured directly by the camera measuring system 11, as shown in FIG. 2. As a result, the deviation of the actual relative position from the desired relative position is at most as great as the accuracy / resolution of the camera measuring system 11. If the accuracy / resolution is, for example, +/- 0.1 mm, then the relative position can be +/- 0.1 mm accuracy / resolution can be determined.

However, the relative position of the robot head 2 to the workpiece carrier 5 can also be determined by measuring the position of the robot head 2 to a reference point and by measuring the position of the workpiece carrier 5 to this reference point and by subsequent subtraction of the two positions. In FIG. 2, for example, a reference point remote from the robot head 2 and the workpiece carrier 5 could be used for this purpose.

In an advantageous embodiment, the measured values of the first and / or second measuring system 8 are stored on reaching the predetermined relative position as a future first and / or second position. In a new positioning process, the first position 13, which is approached by the robot head 2, and the second position, which is approached by the workpiece carrier 5, thus already in the predetermined relative position to each other or at least largely correspond. A repositioning by the camera measuring system 11 will therefore be no longer or only to a small extent necessary. Furthermore, in this way it is ensured that the first position 13 and the second position 14 do not over time due to temperature-induced or plastic deformation of the components involved and aging phenomena and sensor drift of the first measuring system and / or second measuring system 9 from the measuring range 3 shows an example in which the third measuring system comprises a Hall sensor 15 mounted on the head 2 of the robot 3. On the workpiece carrier 5 is a magnet 16 With the aid of the Hall sensor 15, the relative position can now be determined in a manner known per se. on to the magnet 16 and thus the relative position between robot head 2 and workpiece carrier 5 are measured directly.

In a further variant shown in FIG. 4, the machine system 1 comprises a fixedly mounted Hall sensor 15, and a magnet 16 mounted on the workpiece carrier 5 and a magnet 17 mounted on the robot head 2. By subtracting the positions of the magnets 16 and 16 measured by the Hall sensor 15 17, the relative position between the magnets 16 and 17 and thus the relative position between robot head 2 and workpiece carrier 5 can be determined.

In a similar manner as shown in Figures 3 and 4, other sensors can be used, such as Wirbelstromabstandsmeßsensoren, magnetoinductive distance sensors and capacitive distance sensor. In the case of an eddy-current distance measuring sensor, for example, the measuring head takes the place of the Hall sensor 15 and a metallic object to be detected instead of the magnet 16 or the location of the magnet 17. In the case of a capacitive distance sensor, correspondingly electrodes can be provided on the corresponding components of the machine system 1 become.

5 shows a variant of the machine system 1, in which the relative position between robotic head 2 and workpiece carrier 5 is determined by means of laser triangulation. For this purpose, a laser transceiver module 18 is arranged on the robot head, with which a laser beam 19 is directed onto a reflector 20 mounted on the workpiece carrier 5. By evaluating the position of the laser beam 19 received at the laser transceiver module 18, it is again possible to determine the relative position between the robot head 2 and the workpiece carrier 5.

6 shows a further variant for determining the relative position between robot head 2 and workpiece carrier 5. For this purpose, the third measuring system comprises a light source 21, which is mounted on the robot head 2, and an elongate photosensitive element 22, which is mounted stationary. The photosensitive element 22 may be formed, for example, as a transversal diode, CCD or CMOS camera. The relative position between the robot head 2 and the workpiece carrier 5 is determined in this example by evaluating the shadow 23 on the photosensitive element 22, which is detected by the light source 21 from the light source 21. sent light and a trained here as a bolt first shading object 24 on the workpiece carrier 5 is caused. By providing a plurality of transversely aligned light sources 21 or light-sensitive elements 22, the relative position between robot head 2 and workpiece carrier 5 can also be determined in several dimensions. Of course, the same also applies if a photosensitive element 22 which can be evaluated in a multidimensional manner is used. For example, the shadowing object 24 may have a tip or a hole whose position on such a photosensitive element 22 may also be detected in two dimensions. FIG. 7 now shows an embodiment of the machine system 1 which is very similar to the machine system 1 shown in FIG. In contrast, however, the light source 21 is arranged stationary, and on the robot head 2 is a second shading object 25. By evaluating the shadow of the objects 24 and 25, in turn, the relative position of the robot head 2 to the workpiece carrier 5 can be determined. Advantageously, the sensitive measuring system can be arranged in a protected position, the robot head 2 and the workpiece carrier 5, however, are equipped with the relatively insensitive shading objects 24 and 25.

In order to provide an unambiguous assignment of movable unit 2, 5 to the generated shadow 23, the shading objects 24 and 25 may be shaped differently or have a different size. If, for example, the first shading object 24 generates a larger shadow 23 than the second shading object 25, then the association of the detected shadow 23 with the corresponding movable unit 2, 5 can be determined by the size of the shadow 23. Of course, it is also conceivable that the movement of a shading object 24, 25 is used for said assignment. If, for example, the robot head 2 is moved, but the workpiece carrier 5 is not, then the moved shadow 23 is assigned to the robot head 2, while the stationary one is assigned to the workpiece carrier 5

As an alternative to the embodiments shown in FIGS. 6 and 7, FIG

the light source 21 on the robot head 2, the photosensitive element 22 at a fixed point and a first shading object 24 on the workpiece carrier 5, or

the photosensitive member 22 is on the robot head 2, the light source 21 arranged on a fixed point and a first shading object 24 on the workpiece carrier 5.

Of course, the roles of the robot head 2 and the workpiece carrier 5 may also be reversed in the above examples.

It is also advantageous if the first and / or second measuring system 9 are designed as a discontinuous measuring system and the third measuring system 11, 15..25 as a continuous measuring system. In a "discontinuous" measuring system, physical quantities are detected in the form of a step function (digital), as is the case, for example, with the first measuring system of the robot 3 and the rotary encoder 9. In contrast to "discontinuous" measuring systems, a physical variable becomes one "Continuous" measuring system continuously, that is infinitely (analog) detected.

For example, the Hall sensor 15, an eddy current distance measuring sensor, a magnetoinductive distance sensor, a capacitive distance sensor, the laser triangulation sensor 18, and the photosensitive member 22 may continuously adjust the relative position between the robot head 2 and the workpiece carrier 5. This is also possible with the camera 11, provided it is designed as an analogue camera. CMOS and CCD cameras, on the other hand, are part of the discontinuous systems because of the discrete pixels.

The advantages of both measuring systems can be combined by the first and / or second measuring system 9 is designed as a discontinuous and thus very robust measuring system, the third measuring system 11, 15.25 as a continuous and thus usually very accurate measuring system.

In the foregoing examples, the second movable unit was formed as a workpiece carrier 5. Of course, the second movable unit may also have a different construction and be designed, for example, as a tool carrier. In this case, a milling spindle can be arranged on the head 2 of the robot 3, for example, and the tool carriers connected to one another in a ring form a tool magazine for the robot 3. Furthermore, the workpiece carrier 5 need not be connected to each other via a chain. Instead, for example, these can also be connected via a rope or even directly to each other. In a further embodiment, the workpiece carriers 5 can also be embodied as self-propelled units and travel, for example, on the rails 7 or even freely on a running surface.

Of course, the robot 3 does not have to have the illustrated construction. Instead, this can be constructed, for example, as a gantry robot or, for example, have a parallel-kinematic drive instead of the illustrated serial-kinematic drive.

FIGS. 8 and 9 show further embodiments of a machine system 1. The second movable unit is designed as a workpiece carrier 5 or tool carrier, wherein the workpiece carrier 5 or tool carrier is part of a circulating transport chain 26, which comprises a plurality of successively arranged workpiece carrier 5 or tool carrier. The transport chain 26 has a leading, upper strand and a returning, lower strand. The third measuring system 11 is positioned such that at least a portion of the upper strand - in the illustrated embodiment, this is an end region of the upper strand which is upstream of the second position 14 with respect to the conveying direction 27 - within the detection range of the third measuring system 11 is located. Of course, a. With respect to the second position 14 'downstream' arrangement of the third measuring system 11 is possible, as can be seen in Fig. 9. The detection of the second movable unit 5 before reaching the second position 14 by the third measuring system 11 can take place at a predetermined time with respect to a reference point 35 (FIG. 8). This may be a target detected by the optical detection device 11, or simply given by the fixed position of the optical detection device 11. Based on the relative position of a workpiece carrier 5 relative to the reference point 35, the system can control the transport chain 26 (or also the robot head 2) in such a way that the desired relative position between the movable units 2, 5 is achieved reliably and with high accuracy. Fig. 9 shows a variant seen from above, in which the third measuring system 11 is arranged slightly spaced apart from the transport chain 26 and from the end region of the upper strand.

The transport chain 26 is guided by a rotatably mounted on a base frame 31 guide wheels 28, 29 via positive engagement. The transport chain 26 comprises hingedly interconnected chain links via joint axes, which form the workpiece carriers 5 or tool carriers. The joint axis connects in each case two successive workpiece carriers 5 and runs parallel to the axis of rotation of the deflection wheels 28, 29. The third measuring system 11, which is preferably designed as an optical detection device, in particular as a camera, is provided with a control device 32 which comprises an evaluation unit 33 can, connected. The control device 32 is in turn connected to the (second) drive 8 of the transport chain 26. The drive 8 comprises a feed drive at a deflection wheel 28 and a brake drive at the other deflection wheel 29. At least on the advancing drive, a second measuring system 9 is provided or integrated (FIG. 9).

The first movable unit 2 is designed as a manipulation device, in particular as a robot head. The first movable unit 2 moving drive 30 is indicated purely schematically in Fig. 9. This is coupled to the first measuring system 34, which is also shown only schematically. As already mentioned, the first measuring system 34 may comprise an incremental or absolute value encoder on the axes of movement for the second movable unit.

This represents a possibility that

at least one of the first movable unit 2 associated first drive 30 is coupled to approach the first position 13 with the first measuring system 34,

at least one of the second movable unit 5 associated second drive 8 is coupled to approach the second position 14 with the second measuring system 9 and

the first drive 30 and / or second drive 8 is coupled to the third measuring system 11 for approaching the predetermined relative position.

In the exemplary embodiments of FIGS. 8 and 9, the first position 13 and the second position 14 are outside the detection range of the third measuring system 11. The second mobile unit (5) is now already moved through the third measuring position before reaching the second position 14. system 11 is detected. As a result, not only information about the second movable unit 5 (here: workpiece carrier) can be obtained and made available to the machine system, but also information about leading mobile units 5, since they are at a predetermined and substantially invariable distance from each other via the transport chain 26 , Thus, by detecting a single workpiece or tool carrier to the current position of the other, encompassed by the transport chain 26 Werkstückbzw. Tool carrier to be closed.

The third measuring system 11 can be designed to detect the position and / or the size and / or the shape of at least one of the movable units 2, 5 and / or the arrangement of a workpiece or tool on at least one of the movable units 2, 5.

It would also be conceivable that the third measuring system 11 is arranged at least partially on the first movable unit 2 or on the second movable unit 5 or moves along with it (FIG. 10). Such a solution is particularly suitable when the position and / or orientation of a workpiece, component or tool on the movable unit 5 is to be detected. Fig. 10 shows a workpiece carrier 5, which is moved along a conveying direction. The third measuring system 11 designed in this case as an optical detection device can detect the arrangement, in particular position and / or orientation, of a workpiece 36 on the workpiece carrier 5. From this information, the desired relative position (eg for gripping the workpiece 36 by means of a robot head 2) can be determined and approached with high accuracy. Preferably, the machine system is a manufacturing plant for producing an assembly of several parts. Of course, along the transport chain 26 several, even different manipulation devices can be arranged side by side. These form individual work stations, to which the workpiece carrier is transported one after the other. For example, in FIG. 8, a plurality of robot heads 2 could be arranged next to each other. The information acquired by the third measuring system 11 can be forwarded to all manipulation devices, so that they can be controlled on the basis of the information. The embodiments show possible embodiments of a machine system 1 according to the invention, it being noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments are possible with each other and this variation possibility due to the teaching of technical action by objective invention in the skill of those skilled in this technical field. So are all conceivable embodiments, which are possible by combinations of individual details of the illustrated and described embodiment variant, includes the scope of protection.

In particular, it is noted that the illustrated machine systems 1 may in reality also comprise more or fewer components than illustrated.

For the sake of the order, it should finally be pointed out that the machine systems 1, such as their components, have been shown to be somewhat inhomogeneous and / or enlarged and / or reduced in size for a better understanding of their construction.

The task underlying the independent inventive solutions can be found in the Be spelling.

REFERENCE NUMBERS

machine system

first movable unit (robot head)

robot

first movement room

second movable unit (factory trailer:

Chain

rails

second drive

second measuring system (rotary encoder)

Workpiece third measuring system (camera)

Detection area third measuring system

first position

second position

Hall sensor

magnet

Laser transmitter / receiver module

laser beam

reflector

light source

photosensitive element

shadow

first shading object

second shading object

transport chain

conveying direction

guide wheel

First drive

base frame

control device

evaluation

First measuring system

reference point

workpiece

Claims

Patent claims

1. A method for positioning a first movable unit (2) of a machine system (1) and a second movable unit (5) of the machine system (1) in a predeterminable relative position to one another, comprising the steps:

Moving the first movable unit (2) to a first position (13) within a first movement space (4) by means of a first measuring system,

Moving the second movable unit (5) to a second position (14) within a second movement space by means of a second measuring system (9),

characterized in that

the first movable unit (2) and / or the second movable unit (5) is / are moved by means of a third measuring system (11, 15, 25) into said predetermined relative position.

2. The method according to claim 1, characterized in that the first position

(13) and the second position (14) within a detection range (12) of the third measuring system (11, 15.25) lie.

3. The method according to claim 1 or 2, characterized in that

- at least one of the first movable unit (2) associated first drive for starting the first position (13) is coupled to the first measuring system,

at least one second drive (8) assigned to the second movable unit (5) for starting the second position (14) is coupled to the second measuring system (9) and

- The first drive and / or second drive (8) for starting the predetermined

Relative position with the third measuring system (11, 15.25) is coupled / be.

4. The method according to any one of claims 1 to 3, characterized in that the relative position of the first movable unit (2) to the second movable unit (5) by the third measuring system (11, 15.25) is measured directly.

5. The method according to any one of claims 1 to 3, characterized in that the relative position of the first movable unit (2) to the second movable unit (5) by measuring the position of the first movable unit (2) to a reference point and by Measurement of the position of the second movable unit (5) is determined to this reference point by the third measuring system (11, 15.25) and by subsequent subtraction of the two positions.

6. The method according to any one of claims 1 to 5, characterized in that the

Measured values of the first and / or second measuring system (9) on reaching the predetermined relative position as future first and / or second position (13, 14) are stored.

7. The method according to any one of the preceding claims, characterized in that the first position (13) and / or the second position (14) outside the detection range of the third measuring system (11, 15..25) is / are.

8. The method according to any one of the preceding claims, characterized in that the first movable unit (2) before reaching the first position (13) and / or the second te movable unit (5) before reaching the second position (14) by the third measuring system (11, 15.25) is detected / be.

9. The method according to claim 8, characterized in that the detection of the first movable unit (2) before reaching the first position (13) and / or the second movable borrowed unit (5) before reaching the second position (14) through the third measuring system (11, 15.25) takes place at a predetermined time with respect to a reference point (35).

10. The method according to any one of the preceding claims, characterized in that the third measuring system detects the position and / or size and / or the shape of at least one of the movable units (2, 5) and / or the arrangement of a workpiece (5 ) or tool on at least one of the movable units (2, 5) detected.

11. Machine system (1) comprising

a first movable unit (2) which is movable with the aid of at least one first drive in a first movement space (4),

a first measuring system associated with the first movable unit (2), with the aid of which the first movable unit (2) can be positioned at any predeterminable position in the first movement space (4),

a second movable unit (5), which by means of at least a second Drive (8) is movable in a second movement space, wherein the first movement space (4) and the second movement space have an overlap region,

a second measuring system (9) associated with the second mobile unit (5), with the aid of which the second mobile unit (5) can be positioned at any predeterminable position in the second movement space,

marked by

a third measuring system (11, 15, 25) adapted to determine a relative position between the first mobile unit (2) and the second mobile unit (5).

12. Machine system (1) according to claim 11, characterized in that the detection area (12) of the third measuring system (11, 15.25) lies in said overlapping area.

13. Machine system (1) according to claim 11 or 12, characterized by means for coupling

the first drive with the third measuring system (11, 15.25) alternatively / in addition to the first measuring system and / or

of the second drive (9) with the third measuring system (11, 15.25) alternatively / in addition to the second measuring system (9).

14. Machine system (1) according to any one of claims 11 to 13, characterized in that the resolution and / or accuracy of the third measuring system (11, 15.25) is less than that of the first and / or second measuring system (9).

15. Machine system (1) according to any one of claims 11 to 13, characterized in that the resolution and / or accuracy of the third measuring system (11, 15.25) is higher than that of the first measuring system and / or the second measuring system (9 ) and / or sum resolution / Summengenauigkeit of the first and second measuring system (9).

16. Machine system (1) according to any one of claims 11 to 13, characterized in that the first and / or second measuring system (9) as a discontinuous measuring system and the third measuring system (11, 15.25) are designed as a continuous measuring system.

17. Machine system (1) according to any one of claims 11 to 16, characterized in that the third measuring system (11, 15.25) at least one of the group Hall sensor (15), Wirbelstromabstandsmeßsensor, Magnetoinduktiven distance sensor, capacitive Abstandsssensor, Lasertriangulationssensor (18), Sensitive Device position, optical detection device, preferably camera distance sensor.

18. Machine system (1) according to any one of claims 11 to 17, characterized in that the third measuring system (11, 15..25) comprises at least one light source (21) and at least one photosensitive element (22), wherein the relative position between the first movable unit (2) and the second movable unit (5) is determined by evaluating a shadow (23) on the at least one photosensitive element (22) emitted by the light emitted by the at least one light source (21) first movable unit (2) and / or the second movable unit (5) is caused.

19. Machine system (1) according to one of claims 11 to 18, that the first movable unit as a manipulation device, preferably as a head (2) of a robot (3), and the second movable unit as a workpiece carrier (5) or tool carrier are formed.

20. Machine system (1) according to any one of claims 11 to 19, characterized in that a plurality of workpiece carrier (5) or tool carrier are annularly connected to each other, in particular directly connected to each other, attached to a chain (6) or attached to a rope.

21. Machine system (1) according to one of claims 11 to 20, characterized in that the workpiece carrier (5) or tool carrier are designed as self-propelled units.

22. Machine system according to one of claims 11 to 21, characterized in that the first position (13) and / or the second position (14) outside the detection range of the third measuring system (11, 15..25) is / are.

23. Machine system according to one of claims 11 to 22, characterized in that third measuring system (11) for detecting the position and / or the size and / or the shape at least one of the movable units (2, 5) and / or the arrangement or type of a workpiece or tool on at least one of the movable units (2, 5) is formed.

24. Machine system according to one of claims 11 to 23, characterized in that the second movable unit as a workpiece carrier (5) or tool carrier is formed and that the workpiece carrier (5) or tool carrier is part of a circulating transport chain (26), which arranged a plurality of successively Workpiece carrier (5) or tool carrier comprises.

25. A machine system according to claim 24, characterized in that the transport chain (26) has a leading, upper strand and a returning, lower strand and that the third measuring system (11) is positioned such that at least a portion of the upper strand, preferably a End region of the upper strand, within the detection range of the third measuring system (11).

26. Machine system according to one of claims 11 to 25, characterized in that the third measuring system (11) on the first movable unit (2) or on the second movable unit (5) is arranged.

27. Machine system according to one of claims 11 to 26, characterized in that the machine system (1) is a production plant for producing an assembly of several parts.

28. Machine system according to one of claims 11 to 27, characterized in that

at least one of the first movable unit (2) associated first drive (30) for starting the first position (13) is coupled to the first measuring system (34), at least one of the second movable unit (5) associated second drive (8) for starting the second position (14) is coupled to the second measuring system (9) and

the first drive and / or second drive (8) for starting the predetermined relative position with the third measuring system (11, 15.25) is coupled / are.