DE102016214307A1 - Clamping device for a workpiece - Google Patents

Abstract

Clamping device (1, 2) for a workpiece (3) which can be arranged in a coordinate measuring machine (211), comprising an arm (4) which can be fixed on the side of a first end to a base, having at least two segments (10 , 11, 12, 13) and at least one bearing (5, 6, 7, 8, 9, 14), with which the two segments are movably connected relative to each other, - a holding device (16) for the workpiece, which at a second Is attached to the end of the arm, - a measuring device (20, 21, 22, 23, 24) for determining the direction of movement (A, B) or pose at least one of the two segments (10, 11, 12, 13), - a braking device ( 25, 26, 27, 28, 29) whose braking force is controllable, and with which a movement of the two segments relative to each other by increasing the braking force can be braked, - a control device (30) for controlling the braking force of the braking device, wherein the control device with the measuring device and the braking device v is linked

Description

The present invention relates to a flexible jig for a workpiece for a coordinate measurement and to a method for positioning a jig.

For many measuring and machining processes, it is necessary to position a component in a defined position. Flexible fixation devices are known in which fixation columns can be positioned with a coordinate measuring machine (hereinafter CMM) at a freely programmable location and fixed after the height adjustment. Hexagon's "FIVE U-nique" is used to fix parts for testing with a coordinate measuring machine. With the help of the coordinate measuring machine repeatable jigs are created before the execution of the test program. The mechanical system consists of height-adjustable columns available in several sizes, which are positioned as workpiece holders on the base plate of the CMM. The reference position of each column can be stored in software.

In conventional fixation devices, it is only possible with great skill and practice to adjust a defined pose (meaning position and / or orientation) of a workpiece due to the flexibility and lability of parts of the device. In addition, conventional component fixings often need to be planned or designed for a specific component. It is also often necessary to check with the aid of measuring devices whether the desired position of the fixing device corresponds to the specifications.

Object of the present invention is to reproducibly achieve defined with a jig spatial points with high accuracy.

The invention provides a flexible jig for a workpiece having force / travel coupled user guidance.

The advantage of the invention is to represent a flexible and reproducible fixation, which allows to fix a large range of variants of components with few components individually and with little expenditure of time.

• – einen Arm, der auf der Seite eines ersten Endes an einem Untergrund ortsfest fixierbar ist, aufweisend zumindest zwei Segmente und zumindest ein Lager, mit dem die zwei Segmente relativ zueinander beweglich verbunden sind,
• – eine Halteeinrichtung für das Werkstück, die an einem zweiten Ende des Arms angebracht ist,
• – eine Messeinrichtung zur Ermittlung der Bewegungsrichtung oder Pose zumindest eines der zwei Segmente,
• – eine Bremseinrichtung, deren Bremskraft regelbar ist, und mit der eine Bewegung der beiden Segmente relativ zueinander durch Erhöhung der Bremskraft abbremsbar ist, wobei die Bremskraft vorzugsweise derart regelbar oder erhöhbar ist, dass die Segmente in ihrer relativen Lage fixiert sind, sodass eine Bewegung der beiden Segmente relativ zueinander verhinderbar ist,
• – eine Regelungseinrichtung zur Regelung der Bremskraft der Bremseinrichtung, wobei die Regelungseinrichtung mit der Messeinrichtung und mit der Bremseinrichtung verbunden ist

Disclosed is a jig for a workpiece that can be arranged in a coordinate measuring machine, comprising

• - An arm which is fixed on the side of a first end fixed to a substrate, comprising at least two segments and at least one bearing, with which the two segments are movably connected relative to each other,
• A holding device for the workpiece, which is attached to a second end of the arm,
• A measuring device for determining the direction of movement or pose of at least one of the two segments,
• A braking device whose braking force can be regulated, and with which a movement of the two segments relative to each other by increasing the braking force is braked, wherein the braking force is preferably adjustable or can be increased so that the segments are fixed in their relative position, so that movement of the both segments can be prevented relative to one another,
• - A control device for controlling the braking force of the braking device, wherein the control device is connected to the measuring device and to the braking device

• – Übermitteln einer Information über die Bewegungsrichtung oder die Pose zumindest eines der beiden Segmente bei einer Bewegung der beiden Segmente relativ zueinander von der Messeinrichtung an die Regelungseinrichtung,
• – Ermitteln durch die Regelungseinrichtung, ob eine Änderung der Pose oder die Bewegungsrichtung geeignet ist, eine vorgegebene Zielpose der Halteeinrichtung oder eines in von der Halteeinrichtung gehaltenen Werkstücks herzustellen, und
• – Regeln der Bremskraft in der Bremseinrichtung durch die Regelungseinrichtung, sodass die Bremskraft verringert oder nicht angewandt wird, wenn die Änderung der Pose oder die Bewegungsrichtung dazu geeignet ist, die Zielpose der Halteeinrichtung oder des Werkstücks herzustellen oder die Bremskraft erhöht wird, wenn die Änderung der Pose oder die Bewegungsrichtung nicht dazu geeignet ist, die Zielpose der Halteeinrichtung oder des Werkstücks herzustellen.

wherein the measuring device, the braking device and the regulating device are set up to carry out the following steps:

• Transmitting information about the direction of movement or the pose of at least one of the two segments during a movement of the two segments relative to one another from the measuring device to the regulating device,
• - Determining by the control device, whether a change of the pose or the direction of movement is adapted to produce a predetermined Zielpose the holding device or held in the holding device workpiece, and
• - Controlling the braking force in the braking device by the control device, so that the braking force is reduced or not applied when the change of the pose or the direction of movement is adapted to make the Zielpose the holding device or the workpiece or the braking force is increased when the change of Pose or the direction of movement is not suitable to produce the Zielpose the holding device or the workpiece.

The mentioned direction of movement or pose may be a relative or an absolute direction of movement or pose. The direction of movement or pose can be determined absolutely or relatively. Accordingly, the measuring device may be a relatively, in particular incrementally, or absolutely measuring measuring device.

The direction of movement may be the direction of movement of only one of the segments if, during the relative movement of the two segments, only one of them is moved, for example moved in a fixed coordinate system. In particular, the pose is an instantaneous pose of a segment, or both, at a time during movement of one or both segments, or at a time after completion of the movement. To determine the change of a pose, two poses determined at different times are compared.

The movement may be a rotary movement or a translatory movement. In the invention, rotary motion and translational motion can be combined. This means that, in the case of several bearings, pivot bearings and translation bearings and correspondingly coupled segments can be present. Segments may be rotatably or translationally connected relative to each other. It is also possible to provide only one or more pivot bearings or only one or more translation bearings. If a description is given below with reference to joints and rotational movements, the disclosure may alternatively or additionally apply to translatory movements and translational movements.

A bearing mentioned can be a pivot bearing, also referred to as a joint or swivel joint, or a translation bearing, also referred to as a linear bearing. A combination of these is possible.

• – einen Arm, der auf der Seite eines ersten Endes an einem Untergrund ortsfest fixierbar ist, aufweisend zumindest zwei Segmente und zumindest ein Gelenk, mit dem die zwei Segmente relativ zueinander drehbeweglich verbunden sind,
• – eine Halteeinrichtung für das Werkstück, die an einem zweiten Ende des Arms angebracht ist,
• – eine Messeinrichtung zur Ermittlung der Drehrichtung oder Drehposition der zwei Segmente,
• – eine Bremseinrichtung, deren Bremskraft regelbar ist, und mit der eine Drehbewegung der beiden Segmente relativ zueinander durch Erhöhung der Bremskraft abbremsbar ist, wobei die Bremskraft vorzugsweise derart regelbar oder erhöhbar ist, dass die Segmente in ihrer relativen Lage fixiert sind, sodass eine Drehbewegung verhinderbar ist,
• – eine Regelungseinrichtung zur Regelung der Bremskraft der Bremseinrichtung, wobei die Regelungseinrichtung mit der Messeinrichtung und mit der Bremseinrichtung verbunden ist

wobei die Messeinrichtung, die Bremseinrichtung und die Regelungseinrichtung zur Durchführung der folgenden Schritte eingerichtet sind:

• – Übermitteln einer Information über die Drehrichtung oder Drehposition bei einer Drehbewegung der beiden Segmente relativ zueinander von der Messeinrichtung an die Regelungseinrichtung,
• – Ermitteln durch die Regelungseinrichtung, ob die Drehrichtung geeignet ist, eine vorgegebene Zielpose der Halteeinrichtung oder eines von der Halteeinrichtung gehaltenen Werkstücks herzustellen, und
• – Regeln der Bremskraft in der Bremseinrichtung durch die Regelungseinrichtung,
• sodass die Bremskraft verringert oder nicht angewandt wird, wenn die Drehbewegung dazu geeignet ist, die Zielpose der Halteeinrichtung oder des Werkstücks herzustellen oder die Bremskraft erhöht wird, wenn die Drehbewegung nicht dazu geeignet ist, die Zielpose der Halteeinrichtung oder des Werkstücks herzustellen.

In particular, a clamping device for a workpiece is specified, which can be arranged in a coordinate measuring machine, comprising

• An arm which can be fixed in a stationary manner on the side of a first end to a base, comprising at least two segments and at least one joint, with which the two segments are rotatably connected relative to one another,
• A holding device for the workpiece, which is attached to a second end of the arm,
• A measuring device for determining the direction of rotation or rotational position of the two segments,
• - A braking device whose braking force is controllable, and with the rotational movement of the two segments relative to each other by increasing the braking force is braked, wherein the braking force is preferably adjustable or can be increased so that the segments are fixed in their relative position, so that a rotational movement preventable is
• - A control device for controlling the braking force of the braking device, wherein the control device is connected to the measuring device and to the braking device

wherein the measuring device, the braking device and the regulating device are set up to carry out the following steps:

• Transmitting information about the direction of rotation or rotational position during a rotational movement of the two segments relative to one another from the measuring device to the regulating device,
• - Determining by the control device, whether the direction of rotation is adapted to produce a predetermined Zielpose the holding device or a workpiece held by the holding device, and
• - Regulation of the braking force in the braking device by the control device,
• so that the braking force is reduced or not applied when the rotational movement is adapted to establish the Zielpose the holding device or the workpiece or the braking force is increased when the rotational movement is not adapted to produce the Zielpose the holding device or the workpiece.

An aforementioned rotational position is in particular an angular position. The measuring device is in particular an angular position measuring device.

• – Als Aufspannvorrichtung für ein Werkstück in einem KMG
• – als Bauteilaufnahme für die Montage für einen Roboter für die Rohbau-Fertigung im Karosseriebau,
• – als Bauteilaufnahme, die eine prozessrückgekoppelte steuerbare Anpassbarkeit erlaubt, beispielsweise in Verbindung mit Inline-Messtechnik.

The invention can also be applied in the following fields:

• - As a jig for a workpiece in a CMM
• - As a component holder for the assembly for a robot for the body shop in the body shop,
• - As a component recording that allows a process feedback controllable adaptability, for example, in conjunction with inline metrology.

It is provided according to the invention that the operator gets a correct path to the target pose by means of force feedback, in particular computer-controlled force feedback. That is, the device actively brakes during motions that run counter to the target position. As a result, the operator is opposed to a resistance and the way only expedient released or rectified by lifting or weakening of the braking device.

With the invention, a device with a navigation support is provided, which has the operator by controllable resistances the correct setting to achieve a Zielpose the holding device.

According to one idea of the invention, it is provided that a device includes both an integrated measuring device and an axle fixing for each individual bearing, which allows the jig, also referred to as a holding device, fixing device or clamping device to move to a definable spatial point, in particular to move into a defined pose, and then fixate. Upon reaching the Zielpose, which can be a mathematically predetermined position and orientation, the axes of the device can be determined automatically, so that the workpiece can be kept in a defined pose.

According to the invention, a plurality of such clamping devices, for example, three (three-point recording), are used to aufzuspannen a component. For this purpose, the component is held at different locations, each with a holding device of a jig.

Specific applications of the jigs are, for example, to keep a part to be measured with a CMM in a defined position.

Other applications include the fixation of a component in order to fix it in a defined position for joining and machining processes. The jig according to the invention is in the sense not only suitable for coordinate measuring machines, but for holding, fixing and clamping tasks of parts or workpieces in general, in any environment.

The jig according to the invention can be used flexibly. For a production with a multiplicity of variants, a flexible component receptacle is provided which can be adapted flexibly and which allows only a single component receptacle or clamping device to be used for a larger part spectrum.

Furthermore, with the invention, a controllable flexible clamping device can be realized, which makes it possible to specify different desired positions, for example based on previously acquired or defined process parameters, for example determined by an inline or in-process measurement.

In a variant of the invention, the jig on a foot. The foot is used for fixed fixation of the at least one arm. The mentioned arm is connected at a first end to the foot and the foot is in turn fixed in place.

Preferably, two, more preferably six bearings, in particular pivot joints are present in the arm to adjust the pose of the holding device arbitrarily, for example, to reach each space point in any direction (vector) of the holding device Preferably, the number of segments to at least one higher than the number of bearings.

The holding device can be designed so that a workpiece can be placed. The holding device may have a support means. The holding device may alternatively or additionally comprise a fixing device for fixing a workpiece, and is also referred to in this case as a clamping device. The fixing device may be, for example, a two-part or multi-part gripper.

The holding device is preferably coupled to a bearing, in particular a rotary bearing, to a segment, wherein this segment can be referred to as an end segment. In the case of robots, this bearing is also referred to as a "wrist".

The measuring device is in particular an angular position sensor (also angle encoder), in particular a rotary encoder (also: rotary encoder). The angular position encoder or angle encoder can be an incremental encoder (relative detection, in particular digital) or absolute value encoder (absolute angular position, in particular digital).

One or more bearings, in particular each bearing, may be associated with a measuring device.

In particular, when the bearing is a hinge, with the measuring device, the angle of rotation of the joint, i. the angle between two segments, which are interconnected by the joint, determined. The rotational movement of the two segments relative to each other is made possible by the joint movement.

In the presence of several bearings in the arm, the bearings are preferably arranged or configured such that axes of movement, in particular axes of rotation, are present or can be produced with different spatial positions.

The braking device is preferably arranged in or on the bearing. One or more bearings, in particular each bearing, may be associated with a braking device.

The measuring device for determining the direction of movement or pose is preferably arranged in a bearing.

The term "control" is understood to mean in particular a pure control. Thus, the term "control" according to the invention means "control and / or control".

The braking device may be a mechanical brake device, an electric brake device, a magnetic brake device, a fluid brake device or a combination thereof. A specific example is a soft brake.

The control device is connected to the measuring device and the braking device for signal exchange, in particular electrically connected.

The Zielpose the holding device can be defined in a device coordinate system, but also in a workpiece or component coordinate system. These are collectively referred to below as "coordinate system". The Zielpose can be defined with respect to the holding device and / or with respect to the workpiece. In particular, a vector in a target pose or to be reached spatial points of the holding device or the Workpiece defined, in particular set in a coordinate system. A target pose of the workpiece can be specified, for example, if the exact position of the workpiece in the held state, in particular when fixed to the holding device, is known.

The control device is in particular computer-controlled. The control device may be an electronic control or regulating unit with which the achievement of a defined pose of the holding device or a workpiece held by the holding device can be monitored, controlled and / or regulated.

A control device may be a central control device for controlling the braking force of all existing brake devices. Alternatively, a braking device may have its own control device.

The determination as to whether a predetermined target pose is produced or achieved can be made with the knowledge of the geometry of the clamping device, in particular the geometry of the arm. The geometry of the structure, the length of segments and the arrangement of bearings is known in principle. Also, a spatial reference of the holding device to the arm is known. Degrees of freedom in the movement are given by the bearings. In the case of joints, a pose of the holding device can be determined from joint angles or a relative position of segments on the joints. The holding device can itself be connected by a hinge to the arm. In the case of joints, a pose or pose change of the retainer may be determined from a rotational position or a rotational position change at joints. Also, in the case of a joint, a pose or pose change can be determined dynamically from a rotary motion / joint movement. About a joint movement or joint position or joint position change informed the measuring device of a joint. A current pose or a pose change can be compared with a target pose and it can be determined whether an approach to the target pose occurs or not. Accordingly, from this information, the joint movement can be corrected by controlling a braking force in the braking device. With an increase in the braking force, at least one further movement of a joint in a certain direction of rotation can be prevented. The same procedure can be used in the case of translation bearings.

By controlling the braking force, i. variable adjustment of the braking force, the force required to move segments relative to each other is reducible or raisable. A reduction in force, or at least a consistent force, indicates to the operator or operator that the movement is suitable to establish the target pose. An increase in the force by increasing the braking force indicates the opposite case that the movement is not suitable to produce a Zielpose. In this way, a force feedback device is provided, with which a counter force can be generated, which can be counteracted by a first force, which is introduced into at least one of the bearings in order to move the bearing.

In one embodiment, the control device is adapted to increase the braking force in the braking device when reaching the Zielpose so that the segments are fixed in their relative position to each other. In this embodiment, the braking force is increased so that a counterforce by an actuator device or an operator can no longer be generated or generated only under extreme force.

A bearing movement or a movement of segments can be done manually or by an internal or external actuator device. The actuator device can be an external CMM (coordinate measuring machine) but also a robot, depending on the environment in which the flexible device according to the invention is used.

In the apparatus according to the invention or a method according to the invention, a regulation of the braking force for one or more of the bearings can be switched off, in particular an increase in the braking force can be prevented or switched off. This is advantageous if a previously mentioned actuator device, in particular an external actuator device, is used. It can thus be prevented that a braking force counteracts a force of an actuator device, which can lead to damage. It is possible to let the brake force control function in one or more bearings, and to disable the braking force control in one or more other bearings in order to effect a suitable movement with an external actuator device.

In the device according to the invention or a method according to the invention, in one embodiment of the clamping device, the mentioned measuring device can be dispensed with, if in this embodiment the pose is adjusted or adjusted by an external device which executes or causes a movement of the clamping device (eg robot or CMM) and this device can calculate a target pose based on already existing in this device measuring devices. In this simplified embodiment, only controllable parking brakes for fixing the joints after reaching the Zielpose are required.

In manual positioning, the operator is enabled by a controlled force feedback with the jig according to the invention, the path of least resistance to reach the Zielpose and thus realized a high degree of user ergonomics.

In one embodiment, the clamping device has at least one actuator device, namely a mechanical actuator device with which a movement of the segments can be generated. The actuator device can be an internal actuator device, which is arranged inside the clamping device, in particular within a bearing, or an external actuator device. A specific example of an actuator device is an axle motor which is arranged in or on a bearing, in particular a joint. It is a movement, in particular rotation, in one or the other direction generated about the axis, ie a movement of segments relative to each other. An example of an external actuator device is a robot or a CNC axis. Another example of an actuator device is a pneumatic or hydraulic actuator device, in particular acting in one direction actuator device, also referred to as "muscle" which exerts a force on the bearing or one or more segments around the bearing coupled segments, or one of moving in one direction. In this actuator device itself, only one movement can be generated, but if necessary, no exact position can be achieved. With the braking device described, it is quite possible to achieve a target position with a certain uncertainty (but which is known by the rotary encoder).

The clamping device according to the invention for a workpiece can be designed as a robot. For this purpose, an internal actuator device is provided, in particular, through which segments are moved. A jig designed as a robot can also have a further actuator device for the holding device, with which a holding device can automatically hold a workpiece and preferably also grasp it. An actuator device of the holding device can actuate, for example, a previously mentioned fixing device or a previously mentioned gripper.

A jig configured as a robot may be configured in the form of a so-called collaborative robot, i. a robot interacting with a human operator. To ensure sufficient rigidity and holding or carrying capacity for workpieces of higher mass, a robot can be designed accordingly, for example by reinforcement on segments or bearings or correspondingly designed segments or bearings.

In a jig designed as a robot, a plurality of such jigs are preferably used for (jointly) clamping a workpiece.

In one embodiment, the clamping device has a display device on which the direction of movement required to reach the target pose can be displayed at one or more bearings. Each warehouse can be assigned its own display device. The display device may provide the user with an indication of how movement should take place on the bearing in order to reach the target pose of the holding device or a workpiece held in the holding device. The display device is preferably a visual display device. It can display coordinates and / or directions.

The jig may further comprise one or more locking devices, in particular parking brakes. These locking devices are to be distinguished from a previously disclosed braking device whose braking force is adjustable. The locking device serves to determine or lock a bearing position on a bearing. Each bearing may be associated with a locking device.

The control / regulation can furthermore have a function which reads out the final actual position of a measuring device or a plurality of measuring devices, for example angle encoders (in particular incremental encoders or absolute encoders), after the bearing (s) have been fixed. This can be advantageous if the actual achieved target and locked position can not be achieved 100% and the actual deviation for a measurement or machining process must / should be known by e.g. to be available for corrections of a measurement process or machining process or determined measurement results.

The output of deviations can be via the notification of the individual deviations of each individual axis (single axis), but also as a calculated total deviation (eg position (X / Y / Z) and direction / rotation (A, B, C), in particular the "Tool Center Points (TCP) of each segment.

The output of the deviation can also be done for several axes of rotation as position and direction / rotation deviation for an entire workpiece.

Here, the control device could either raw data, eg values of the measuring devices, but also completely calculated results as vectors transformation matrices for a Provide further use in other systems (CMM / processing machine).

Since every mechanical axis is subject to bending depending on the weight of the workpiece fixed thereto, but also because of its own weight, it may be necessary to determine or calculate a bending empirically, for example via FEM methods ("finite element methods"), and to incorporate this value in the deviation of the target position mentioned above. The invention further provides an arrangement comprising at least two preceding jigs. These can clamp a workpiece together by holding each of the jigs with their holding device the workpiece. The jigs can be fixed in place on a base, for example on a measuring table of a CMM or on a machine tool.

• a) Bereitstellen einer Aufspannvorrichtung wie zuvor beschrieben,
• b) Vorgeben einer Zielpose der Halteeinrichtung oder einer Zielpose einer von der Halteeinrichtung zu haltenden Werkstücks,
• c) Erzeugen einer relativen Bewegung der zumindest zwei Segmente durch Einleiten einer Kraft in das Lager, insbesondere in mindestens eines der Segmente,
• d) Übermitteln einer Information über eine Bewegungsrichtung oder Pose zumindest eines der Segmente von der Messeinrichtung an die Regelungseinrichtung,
• e) Ermitteln durch die Regelungseinrichtung, ob eine Änderung der Pose oder die Bewegungsrichtung geeignet ist, die Zielpose der Halteeinrichtung oder des Werkstücks herzustellen, und
• f) Regeln der Bremskraft in der Bremseinrichtung durch die Regelungseinrichtung, sodass die Bremskraft verringert oder nicht angewandt wird, wenn die Änderung der Pose oder die Bewegungsrichtung dazu geeignet ist, die Zielpose der Halteeinrichtung oder des Werkstücks herzustellen oder die Bremskraft erhöht wird, wenn die die Änderung der Pose oder die Bewegungsrichtung nicht dazu geeignet ist, die Zielpose der Halteeinrichtung oder des Werkstücks herzustellen,
• g) Weiterbewegen des Segmentes oder der Segmente in der Bewegungsrichtung wenn die Bremskraft verringert wird oder nicht angewandt wird, oder Bewegen des/der Segmente in die entgegengesetzte Bewegungsrichtung wenn die Bremskraft erhöht wird.

In a further aspect, the invention relates to a method for adjusting or positioning a jig, comprising:

• a) providing a jig as described above,
• b) predetermining a target pose of the holding device or a target pose of a workpiece to be held by the holding device,
• c) generating a relative movement of the at least two segments by introducing a force into the bearing, in particular in at least one of the segments,
• d) transmitting information about a direction of movement or pose of at least one of the segments from the measuring device to the regulating device,
• e) determining by the control means whether a change of the pose or the direction of movement is suitable for producing the target pose of the holding device or the workpiece, and
• f) controlling the braking force in the braking device by the control means, so that the braking force is reduced or not applied when the change of the pose or the direction of movement is adapted to make the Zielpose the holding device or the workpiece or the braking force is increased when the Change of pose or the direction of movement is not suitable to produce the Zielpose the holding device or the workpiece,
• g) advancing the segment or segments in the direction of movement when the braking force is reduced or not applied, or moving the segment (s) in the opposite direction of movement when the braking force is increased.

In the method, all objective features can be realized, which were previously disclosed by means of a jig according to the invention. Likewise, conversely, a clamping device disclosed above can be set up or configured to carry out procedural steps.

During the process, the clamping device can be fixed in place on a base, for example on a measuring table of a CMM or on a machine tool.

In general, procedural steps, possibly or meaningful, can also take place in a sequence other than that mentioned.

The method can be repeated in steps e), f) and g), optionally also d), until the target pose is reached.

The process can be done without a workpiece. As a further step, the method may include: clamping the workpiece in the clamping device, in particular holding, and preferably also fixing, to the mentioned holding device. This step may occur at any time, such as at the beginning of the procedure or at the end of the procedure. In this sense, the method is then also referred to as a method for positioning a workpiece.

After a predetermined time interval, a movement by a predetermined amount, or a predetermined position change, in particular after a predetermined rotation angle, or a predetermined rotation angle change, the steps e), f) and g) can be performed again to monitor the movement and positioning , For example, a segment may have been moved too far in one direction and must be moved in an opposite direction again to make the target pose.

Finally, upon reaching the Zielpose in the process, the braking force can be increased so far that the segments are fixed in their relative position.

Finally, when the target pose is reached in the method, an absolute deviation from a predefined setpoint value can be determined by reading out the position, in particular the absolute position, of one or more measuring devices, in particular one or more angular position sensors.

The invention further provides a coordinate measuring machine comprising a jig as disclosed above. The coordinate measuring machine can be set up or configured to carry out a method described above.

The invention will be described below with reference to exemplary embodiments. Show it:

1 an arrangement of two clamping devices according to the invention,

2 a deviation from a goal pose, and the determination of the current pose

3 an inventive coordinate measuring machine and

4 a process sequence according to the invention.

In 1 are the jigs 1 . 2 imaged in which the workpiece or component is clamped. The arm 4 the jig 1 has as bearings the joints 5 . 6 . 7 . 8th . 9 on. The examples relate exclusively to rotational movements, but this does not limit the invention, which is also or alternatively applicable to translational movements with appropriate design of one or more bearings.

Further, the arm points 4 the segments 10 . 11 . 12 . 13 on. The segments 10 and 11 are through the swivel 5 connected to the segments 11 and 12 are through the swivel 6 connected and the segments 12 . 13 are by the combined, biaxial swivel 7 . 8th connected. The axes of rotation D ₁ , D ₂ , D ₃ and D ₅ are in the current rotational position perpendicular to the viewing direction of the viewer. The axis of rotation D _{4 of} the joint part 8th points down. Furthermore, there is still the hinge 14 with the rotation axis D ₆ available. The swivel joint 14 is with the foot plate 15 connected over which the jig 1 can be fixed to a substrate. In this case, the joint forms 14 the first end of the arm 4 , The joint 9 forms the second end of the arm 4 , At the joint 9 is the holding device 16 hinged, the lower gripper 17 and the upper gripper 18 having. The lower gripper 17 has at its end a storage means 19 on. The grippers 17 . 18 are shown in the open position.

The jig 2 on the right side of 1 has the same structure as the jig 1 , Reference numerals have been omitted for clarity, but would otherwise be identical. Based on the jig 2 Further elements are shown, which also in the jig 1 available. Shown are on the one hand measuring equipment 20 . 21 . 22 . 23 . 24 that are inside the joints 5 . 6 . 7 . 8th . 14 are arranged. These measuring devices are shown only schematically. Also shown schematically are braking devices 25 . 26 . 27 . 28 . 29 ,

The control device 30 is computer-controlled and on the one hand with the measuring equipment 20 - 24 and on the other hand with the braking device 25 - 29 connected. By way of example, only a connection to the measuring device is shown 20 and the braking device 25 ,

At the hinge 6 the right chuck 2 is also a display device 31 shown, on which the direction of rotation required to reach a Zielpose can be displayed. In this case, a clockwise arrow will be displayed indicating that the segment 12 should be turned clockwise. At other hinges corresponding display devices are present.

In the swivel joints present actuator devices for effecting the joint rotation are in 1 not shown.

The jig shown on the left 1 also has a control device 30 , Measuring equipment 20 - 24 , Braking devices 25 - 29 and display devices 31 on, but not shown.

2 shows for understanding the manner in which a target pose can be defined and how it can be determined whether a rotational direction or rotational position of two segments is suitable for establishing the target pose.

The current pose of the holding device 16 can be obtained by adding the vectors X1, X2, X3, X4 and X5. The lengths and start and end points of the vectors are each determined by the structure of the jig 1 firmly defined, namely by the geometry of the arms and joints. The position of the vectors X1 to X5 is described in the Cartesian coordinate system shown on the left. The origin of the coordinate system can be set to the beginning of the vector X1 or elsewhere. The current pose of the holding device 16 is described by the vector X5. As a target pose, the vector should occupy the position X5 ', which is shown by dashed lines. In the control device 30 the vector addition can be made permanently and it can be determined whether the target pose X5 'has already been occupied or whether the target pose X5' is at least approaching. Accordingly, brake devices 26 - 29 controlled so that a movement facilitates the target position and a joint movement, which leads away from the Zielpose, is difficult.

This in 3 illustrated coordinate measuring machine (CMM) 211 in portal construction has a base 201 up, over the pillars 202 . 203 are movably arranged in the Y direction of a Cartesian coordinate system. The columns 202 . 203 make up together with a crossbeam 204 a portal of the CMM 211 , The crossbeam 204 is at its opposite ends with the pillars 202 respectively. 203 connected. Not shown electric motors cause the linear movement of the columns 202 . 203 in the Y direction, along the Y motion axis. It is z. B. each of the two columns 202 . 203 associated with an electric motor. The crossbeam 204 is with a cross slide 207 combined, which air-stored along the cross member 204 movable in the X direction of the Cartesian coordinate system. The current position of the cross slide 207 relative to the cross member 204 can be based on a scale division 206 be determined. The movement of the crossbeam 204 in the X-direction, ie along the X-motion axis, is driven by another electric motor. At the cross slide 207 is a vertically movable quill 208 stored at its lower end via a mounting device 210 and a turning device 205 with a probe 209 connected is. To the probe 209 is the angled button 215 coupled to which a stylus 111 with tactile ball 121 is arranged detachably. The probe 209 can be driven by another electric motor relative to the cross slide 207 in the Z direction, along the Z-motion axis, of the Cartesian coordinate system. By the electric motors of the CMM, the probe can 209 in the area below the cross member 204 be moved in almost any position. Furthermore, the rotating device 205 the probe 215 rotate around the Z axis so that the stylus 111 can be aligned in different directions.

On the base 201 of the CMM 211 is the in 1 explained jig 1 attached. Of course, another jig 2 to be available.

4 shows a method sequence according to the invention according to a specific embodiment, which includes the step S1, which is not mandatory. First, in step S1, a workpiece 3 in the jig 16 both shown in 1 , clamped. Then the target pose X5 ', which is in 2 is shown for the holding device 16 given, which is designated by step S2. In general, procedural steps, possibly or meaningful, can also take place in a different order. Step S1 can also be done when a target pose is reached. If, for example, a target pose for an already set up component or workpiece is to be readjusted with the clamping device, one can first produce the target pose and at the end place or fix the component.

Subsequently, in step S3, a relative rotational movement of the segments 10 . 11 . 12 . 13 by introducing forces into joints 5 . 6 . 7 . 8th . 9 . 14 generated. It is not mandatory that each segment or joint must be moved.

Subsequently, in step S4, information about a relative direction of rotation of segments of measuring devices 20 . 21 . 22 . 23 . 24 to the control device 30 transmitted. The measuring devices mentioned are angular position sensors. Only in joints where a rotational movement takes place is it necessary to transmit information about a relative direction of rotation.

In step S5, in the control device 30 determines if the relative direction of rotation of the segments 10 . 11 . 12 . 13 is suitable, the Zielpose X5 'of the holding device 16 manufacture. Alternatively, the target pose of a workpiece 3 be specified. A target pose of the workpiece can be specified, for example, when the exact position of the workpiece in the clamped state, ie when gripping the holding device 16 , is known.

In subsequent step S6, the braking force is regulated in braking devices 25 . 26 . 27 . 28 . 29 through the control device 30 , It is only necessary to regulate the braking force of such joints that are being moved. The braking force is reduced or not applied when the relative rotational direction of segments is adapted to the target pose X5 'of the fixture 16 manufacture. For example, in 2 the segment 12 opposite the segment 11 by a rotation on the joint 6 Turned clockwise, then this movement is suitable, the target pose X5 ', which under the current pose of the holding device 16 lies to produce. In this case, no braking force is applied or an existing braking force is reduced. The movement of the segment 12 clockwise is indicated by the arrow A. If, however, a direction of rotation of the segment 12 counterclockwise, denoted by the arrow B, then this movement is not suitable to make the pose X5 'and there is a braking intervention, ie the braking force of one in the joint 6 arranged braking device is increased.

In step S7, the exemplary segment then becomes 12 Turned clockwise, if previously the movement was already clockwise. Was the rotation in the direction of arrow B is not suitable to make the target pose X5 ', then an opposite direction of rotation A is set, that is changed from the direction of rotation B counterclockwise in a direction of rotation A clockwise.

After a certain time interval or rotation angle, steps S5, S6 and S7 are again performed to monitor the movement and positioning. For example, it could be that segment 12 is rotated too far in the direction A and must be turned back in the direction B to make the target pose X5 '. The repetition of steps S5, S6, S7 is shown by an arrow leading from S7 to S5. Optionally, step S4 can also be carried out again, which is indicated by a dashed arrow.

LIST OF REFERENCE NUMBERS

1, 2

fixtures

4

poor

5, 6, 7, 8, 9

joints

10, 11, 12, 13

segments

14

swivel

15

footplate

16

holder

17, 18

grab

19

bearing means

20, 21, 22, 23, 24

measuring equipment

25, 26, 27, 28, 29

braking devices

30

control device

31

display

111

feeler

121

probe ball

201

Base

202, 203

columns

204

crossbeam

205

rotator

206

scale graduation

207

cross slide

208

Pinole

209

probe

210

mounter

211

coordinate measuring machine

215

button

A, B

directions of movement

D ₁ , D ₂ , D ₃ , D ₄ , D ₅

rotational axes

S1, S2, S3, S4, S5, S6, S7

steps

X1, X2, X3, X4, X5

vectors

X5 '

target pose

Claims (9)

Clamping device ( 1 . 2 ) for a workpiece ( 3 ) in a coordinate measuring machine ( 211 ), comprising - an arm ( 4 ), which is fixable on the side of a first end to a base fixed, comprising at least two segments ( 10 . 11 . 12 . 13 ) and at least one warehouse ( 5 . 6 . 7 . 8th . 9 . 14 ), with which the two segments are movably connected relative to each other, - a holding device ( 16 ) for the workpiece, which is attached to a second end of the arm, - a measuring device ( 20 . 21 . 22 . 23 . 24 ) for determining the direction of movement (A, B) or pose at least one of the two segments ( 10 . 11 . 12 . 13 ), - a braking device ( 25 . 26 . 27 . 28 . 29 ), whose braking force is controllable, and with which a movement of the two segments relative to each other by increasing the braking force can be braked, - a control device ( 30 ) for controlling the braking force of the braking device, wherein the regulating device is connected to the measuring device and to the braking device, wherein the measuring device ( 20 . 21 . 22 . 23 . 24 ), the braking device ( 25 . 26 . 27 . 28 . 29 ) and the control device ( 30 ) are arranged to carry out the following steps: transmission of information about the direction of movement (A, B) or the pose of at least one of the two segments during a movement of the two segments ( 10 . 11 . 12 . 13 ) relative to each other from the measuring device to the control device, - determined by the control device ( 30 ), whether a change of the pose or the direction of movement (A, B) is suitable, a predetermined target pose (X5 ') of the holding device ( 16 ) or a workpiece held by the holding device ( 3 ), and - controlling the braking force in the braking device ( 25 . 26 . 27 . 28 . 29 ) by the control device ( 30 ), so that the braking force is reduced or not applied, if the change of the pose or the direction of movement is suitable, the target pose (X5 ') of the holding device ( 16 ) or the workpiece or the braking force is increased, if the change of the pose or the direction of movement is not suitable, the target pose (X5 ') of the holding device ( 16 ) or the workpiece ( 3 ). Clamping device according to claim 1, wherein the control device ( 30 ) is adapted to increase the braking force in the braking device when reaching the Zielpose (X5 ') so that the segments ( 10 . 11 . 12 . 13 ) are fixed in their relative position. Clamping device according to claim 1 or 2, comprising at least one mechanical actuator device, with which a movement of the segments ( 10 . 11 . 12 . 13 ) is producible. Clamping device according to one of the preceding claims, comprising a display device ( 31 ) on which the direction of movement required to reach the target pose can be displayed. Method for adjusting or positioning a clamping device, comprising: a) providing a clamping device ( 1 ) according to any one of claims 1-4, b) predetermining (S2) a Zielpose (X5 ') of the holding device ( 16 ) or a target pose of a workpiece to be held by the holding device, c) generating (S3) a relative movement of the at least two segments ( 10 . 11 . 12 . 13 ) by introducing a force into the bearing ( 5 . 6 . 7 . 8th . 9 . 14 ) d) transmitting (S4) information about a direction of movement (A, B) or pose of at least one of the segments ( 10 . 11 . 12 . 13 ) of the measuring device ( 20 . 21 . 22 . 23 . 24 ) to the control device ( 30 ), e) determining (S5) by the control device ( 30 ), whether a change of the pose or the direction of movement (A, B) is suitable, the target pose (X5 ') of the holding device ( 16 ) or the workpiece, and f) regulating (S6) the braking force in the braking device ( 25 . 26 . 27 . 28 . 29 ) by the control device ( 30 ), so that the braking force is reduced or not applied when the change of the pose or the direction of movement (A) is adapted to the target pose (X5 ') of the holding device (FIG. 16 ) or the workpiece or the braking force is increased, if the change of the pose or the direction of movement (B) is not suitable, the target pose (X5 ') of the holding device ( 16 ) or the workpiece, g) moving on (S7) of the segment or segments ( 10 . 11 . 12 . 13 ) in the direction of movement (A) when the braking force is reduced or not applied, or moving the segment (s) in an opposite direction of movement (B) when the braking force is increased.  The method of claim 5, comprising: repeating steps e) -g) until the target pose is reached.  The method of claim 6, comprising increasing the braking force in the braking device upon reaching the Zielpose such that the segments are fixed in their relative position. Method according to one of claims 5-7, comprising laying and / or fixing (S1) of the workpiece ( 3 ) on the holding device ( 1 ). Coordinate measuring machine ( 211 ), comprising a jig ( 1 ) according to any one of claims 1-4, or adapted for carrying out a method according to any one of claims 5-8.

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