DE102019205042B4 - Device and method for positioning a sensor or sensor part - Google Patents

Abstract

Device for positioning a sensor (2) or sensor part for generating measurement points when measuring a measurement object, the device (1) having at least one holding device (3) for linear drive devices (6a, 6b, 6c, 6a1,..., 6c2), comprises a first, a second and at least a third linear drive device (6a, 6b, 6c) and at least one holding element (8) for the sensor (2), each of the linear drive devices (6a, 6b, 6c, 6a1,..., 6c2 ) is mounted on the holding device (3), with part of the linear drive device (6a, 6b, 6c, 6a1,..., 6c2) forming part of the holding device (3), with each of the linear drive devices (6a, 6b, 6c, 6a1,...,6c2) is mechanically connected to the holding element (8), characterized in that the device has at least one position detection device (21) for detecting a position of the holding element (8) or a sensor ( 2) comprises the position detection device (21) being an optical position detection device (21), at least one image detection device (15) of the optical position detection device (21) being arranged on the holding device (3).

Description

The invention relates to a device and a method for positioning a sensor or sensor part for generating measurement points when measuring a measurement object.

Known from the prior art are coordinate measuring devices that can measure a measurement object using so-called tactile sensors or optical sensors and generate measurement points for this purpose. A desired position of a sensor in space can be adjusted by means of the coordinate measuring device.

In particular, coordinate measuring devices are known in a so-called column or portal design. These include a positioning device with moving parts that can be moved along mostly linear trajectories, with these trajectories being oriented in different spatial directions. By moving the moving parts, for example, positioning can take place along three different spatial directions, which can be oriented in particular at right angles to one another.

In principle, the positioning devices of these known coordinate measuring devices have so-called serial kinematics. It is known that this serial kinematics can achieve high rigidity, high positioning accuracy when positioning the sensor and thus high accuracy when generating measurement points.

Further known is the DE 195 34 535 C2 , which discloses a coordinate measuring machine with a positioning mechanism, which comprises legs pivoted on all sides on a base frame at least three fixed pivot points, with at least three legs being adjustable in length.

The U.S. 2017/0 258 531 A1 discloses an optical tracking system and optical tracking method based on passive markers.

The U.S. 6,575,676 B2 discloses parallel machine tools in which kinematic legs are arranged in parallel between a base and a mobile platform.

The DE 10 2015 106 831 A1 discloses an air bearing arrangement with at least one air bearing for the movable mounting of two components relative to one another.

The FR 2 779 080 A1 discloses high-speed machining and, in particular, adjustments that allow a tool to be moved in optimal conditions for machining operations.

The EP 1 125 693 A1 discloses a parallel kinematic system in which at least two actuators act in parallel kinematic positioning on an end effector device and are each articulated to it by connecting means in at least two degrees of freedom of movement and in which the actuators each have a runner guided by a stator along a longitudinal movement axis.

The DE 10 2017 118 717 A1 discloses a device for operating a flap on an aircraft wing.

The WO 2016/071227 A1 discloses optical tracking systems and methods based on passive markers.

It is desirable to reduce the weight, the production costs and the required installation space of a device for positioning a sensor for generating measurement points and to improve dynamics, in particular to enable faster positioning in terms of time.

There is therefore the technical problem of creating a method and a device for positioning a sensor or sensor part for generating measuring points when measuring a measurement object, which is easy to produce, reduces the weight, the production costs and the space requirement, and is fast and reliable Allow positioning of the sensor. There is also the problem of creating a device and a method with adjustable working spaces and/or a high loading capacity. There is also the problem of creating a device and a method that enable a rapid measurement with different sensors or sensor parts, in particular a rapid exchange of sensors or sensor parts. There is also the problem of creating a device and a method with increased measurement accuracy.

The solution to the technical problem results from the subject matter having the characteristics of the independent claims. Further advantageous configurations of the invention result from the dependent claims.

A device for positioning a sensor or sensor part for generating measurement points when measuring a measurement object is proposed. The device can be part of a coordinate measuring device or -be machine. Unless expressly stated otherwise, the following statements regarding a sensor also apply to a sensor part. In this case, the positioning can enable the setting of a spatial position of the sensor. A position in space can denote a position and/or an orientation and can also be referred to below as a position.

The position in space can be defined in a reference coordinate system or related to this reference coordinate system. In this reference coordinate system, for example, a vertical axis can be oriented parallel and opposite to the direction of a weight force. A longitudinal and a transverse axis of the reference coordinate system can be oriented perpendicular to one another and span a plane which in turn is oriented perpendicular to the vertical axis.

In this case, the sensor can be an optical sensor that generates measuring points optically, ie based on optical measuring methods. Alternatively, the sensor can also be a tactile sensor that generates measurement points by touching the measurement object, ie by means of contacting methods.

The sensor part can be a part of the sensor, in particular a movable part which is arranged movably relative to a stationary part of the sensor, wherein the stationary part can be attached to a further holding or a further positioning device. In the case of a tactile sensor, the sensor part can in particular be or include the part of the sensor that touches the measurement object to generate measurement points. For example, the sensor part can comprise a button or a button element, such as a button ball. In the case of an optical sensor, the sensor part can in particular be the part or comprise the part of the sensor which, in order to receive rays from the measurement object, is aligned with the latter in order to generate measurement points.

The sensor can be positioned in the desired spatial positions by means of the device. In the case of a sensor part, the device can be used to position the sensor part in a desired spatial position relative to a stationary part of the sensor. The sensor can also be moved by means of the device along desired trajectories, in particular along a trajectory specified by a test plan, with measuring points then being able to be generated during the movement along the trajectories.

The device comprises at least one holding device for linear drive devices. The holding device can be designed as a frame or comprise a frame. Furthermore, part of the linear drive device forms part of the holding device. This is explained in more detail below. It is possible for the holding device to have a base area, with a number of corners of the base area being equal to the number of linear drive devices. The holding device can also have a base area which is circular, oval or of another geometric shape.

The holding device can be attached to or comprise a base plate. For example, the surface of the base plate or part of it can form the base area. The base plate can be a measuring table or can be formed from it.

In particular, the base plate or the base area can be used to arrange a measurement object. When arranged on the base plate, this can be arranged in particular in a working area of the device.

A linear drive device can, in particular, comprise a movable element which/which can be moved along a linear, ie rectilinear, trajectory. The movable element can therefore be part of the linear drive device. Furthermore, a linear drive device can include an actuator for generating a drive force, in which case the term “force” in the context of this invention can also designate a torque. Furthermore, a linear drive device can comprise at least one gear element, at least one coupling element and/or at least one guide element for guiding the movement. The movable element, which can also be referred to as the output element, can be mechanically coupled to the actuator via a gear or a coupling element. The movement of the movable part can be guided by means of the guide element.

Furthermore, the device comprises a first, a second and at least a third linear drive device, these linear drive devices being different from one another.

Furthermore, the linear trajectories along which the movable elements of the linear drive devices move can be arranged stationary in the reference coordinate system. However, it is also conceivable that a spatial position of these linear trajectories change during the execution of a linear movement in the reference coordinate system.

If the linear trajectories are stationary, they can be oriented parallel to one another. However, there are also embodiments conceivable in which at least two different linear trajectories are not oriented parallel to one another, in particular are arranged askew or intersect at one point.

The device also includes at least one holding element for the sensor. The sensor can be attached to the holding element or can be attachable. So it is conceivable that the sensor is non-detachably, that is not detachable non-destructively, attached to the holding element. However, the sensor is preferably detachably attached to the holding element. A detachable connection can be, for example, a clamp connection, a latching connection, a screw connection or a detachable connection of a different design. A non-detachable connection can be, for example, an adhesive connection, a welded connection, a soldered connection, a riveted connection or a non-detachable connection of a different design.

In particular, the sensor can be fastened to the holding element in such a way that it has a predetermined position in a holding element-specific coordinate system in the fastened state, ie also after each fastening. This enables the sensor to be fastened to the holding element with repeat accuracy.

For this purpose, the holding element can have corresponding fastening and/or connecting means, in which case these can be designed and/or arranged in such a way that the previously explained fastening of the sensor is made possible. Of course, the sensor can have appropriate fastening and/or connecting elements.

It is conceivable that the sensor, in particular a sensor housing, is fastened or can be fastened directly to the holding element. However, it is also conceivable that the sensor is/can be fastened/fastened to the holding element via at least one connecting element, ie indirectly. In the latter case, in particular, the connecting element can have corresponding connecting or fastening elements for connection to the holding element.

The holding element can be designed in particular in the form of a plate.

Furthermore, the linear drive devices or at least a part thereof, e.g. the movable elements of the linear drive devices, are mounted on the holding device, in particular via a bearing device. For example, a linear drive device can be mounted on the holding device via a rotary bearing device. The rotary bearing device can enable a relative rotational movement between the holding device and a linear drive device, in particular the movable element. The relative rotary movement can be a rotary movement with exactly one degree of freedom, exactly two degrees of freedom or exactly three degrees of freedom. In other words, the linear drive device can be mounted on the holding device such that it can rotate about exactly one axis of rotation, about exactly two axes of rotation that differ from one another, or about exactly three axes of rotation that differ from one another.

Alternatively, a linear drive device or a part thereof can be mounted in a linearly movable manner on the holding device, in particular if a part of a linear drive device forms part of the holding device.

A linear drive device can also be mounted rigidly on the holding device.

It is also possible for a linear drive device to be mounted on the holding device so that it can move freely. The fact that a linear drive device can be freely movably mounted on the holding device can mean in particular that the linear drive device or a part thereof is movably mounted on the holding device with two or more translational degrees of freedom, in particular translational degrees of freedom that differ from one another.

Furthermore, each linear drive device, in particular each of the movable elements, is mechanically connected to the holding element or mounted on it. In particular, the linear drive devices can be mechanically connected to the holding element via a bearing device, in particular a rotary bearing device.

Corresponding to the above explanations regarding the mounting of a linear drive device on the holding device, a linear drive device or a part thereof can be mechanically connected to the holding element such that it can rotate about exactly one axis of rotation, about exactly two axes of rotation that differ from one another, about exactly three axes of rotation that differ from one another, or about more than three axes that differ from one another be stored at this. Alternatively or cumulatively, it is possible for a linear drive device or a part thereof to be mechanically connected to the holding element or mounted on it so that it can move with precisely one translational degree of freedom. A linear drive device can also be freely movably connected to the holding element or be mounted on it.

The connection points or sections for connecting the at least three linear drive devices to the holding element can here be arranged in different positions in the coordinate system specific to the holding element.

It is possible for the holding element to be additionally mounted on the holding device, with the mounting not taking place via one of the linear drive devices, ie being independent of these.

If the device is a device for positioning a sensor part, the holding device and the linear drive devices can be part of the sensor. The sensor part to be positioned can be fastened or can be fastened to the holding element.

In this case, the stationary part of the sensor can include the holding device and the base plate that may be present

The proposed device advantageously results in reliable and precise positioning of a sensor attached to the holding element.

By adjusting a position of the movable elements of the linear drive devices, which can also be referred to as driven elements, a position of the holding element and thus also a position of a sensor attached thereto can be adjusted in an advantageous manner. A position of the sensor in the coordinate system specific to the holding element can be previously known or defined by the design of the corresponding connection/fastening means. In this case, a desired position of the sensor can be adjusted by adjusting the position of the holding element.

A working space of the proposed device for positioning can designate a spatial area that includes the positions in which the sensor can be positioned using the device. Also, the working space can denote the positions in which the sensor can be positioned with one or more predetermined orientation(s).

The proposed device enables the sensor to be positioned quickly in terms of time. Furthermore, in particular due to the parallel kinematic structure of the device, weight, space requirements and thus also costs in the manufacture of the device are reduced.

In a further embodiment, a linear drive device comprises a linear guide element and a carriage, the carriage being mounted on the linear guide element so that it can move linearly. In this case, the carriage can form the movable element of the linear drive device or a part thereof. In particular, the linear guide element can be arranged in a stationary manner in the previously explained reference coordinate system. Furthermore, the linear guide element can form part of the holding device. It is conceivable, for example, that corners of the base area of the holding device are formed or fixed by linear guide elements and edges of the base area by connecting elements of the linear guide elements.

For example, it is conceivable that the linear guide element is rod-shaped. Furthermore, the linear guide element can have or form guide means for guiding the movement of the carriage, e.g. a guide groove or a guide web. The carriage can be mechanically connected to the holding element.

In this case, the linear guide elements can have a longitudinal axis, for example an axis of symmetry, with longitudinal axes of the linear guide elements being arranged parallel to one another and at a distance from one another in the reference coordinate system. As explained above, the linear trajectories defined by the linear guide elements can also be arranged parallel to one another and at a distance from one another.

Designing the linear drive devices with a linear guide element and a carriage advantageously results in a simple design of the linear drive devices, which enables a position of the movable element to be set quickly and precisely along the linear trajectory of the corresponding linear drive device.

In a further embodiment, a linear drive device comprises a coupling element for connecting the carriage and the holding element. The coupling element, in particular a first end of the coupling element, can be mechanically connected to the holding element, in particular via the bearing device explained above. Furthermore, the coupling element, in particular a further end of the coupling element, can be mechanically connected to the carriage. It is possible here for the coupling element to be connected to the carriage via a bearing device, in particular a rotary bearing device.

The coupling element can be rod-shaped. Furthermore, the coupling element can have a predetermined length. It is possible for the lengths of the coupling elements of all linear drive devices to be the same. Alternatively, it is also possible that the length of a coupling element at least one linear drive device from the Length / the lengths of the coupling elements of the other linear drive devices is different.

The coupling element advantageously results in a simple mechanical configuration of the device for positioning, which has a desired working space, in particular a desired size.

In a further embodiment, a carriage is mounted on the linear guide element via an air bearing device. This results in an advantageous way in a simple and reliable mounting and linear guidance and thus a high positioning accuracy of the device.

In a further embodiment, the device comprises at least one pair of linear drive devices with two linear drive devices. Furthermore, at least one movable element of a first linear drive device of the pair of linear drive devices can be mechanically rigidly connected or is connected to a movable element of a second linear drive device of the pair of linear drive devices.

In a connected state, the moveable elements are mechanically rigidly connected. In an unconnected state, the moveable elements are not mechanically connected to each other.

In this case, the mechanical connection can be established via a connecting element of the pair of linear drive devices. The connecting element can in particular be in the form of a rod. In this case, the connecting element can be fixed mechanically rigidly to the movable elements. If the linear trajectories, along which the movable elements of the two linear drive devices of the linear drive device pair move, are spatially fixed in the reference coordinate system, they can be oriented parallel to one another in particular. Furthermore, a minimum length connecting line of the trajectories cannot intersect a working space of the device, ie it can be arranged outside of the working space.

The mechanical connection between the moving parts can in particular be a detachable connection. The mechanical connection of the moving parts ensures that they move in parallel and to the same extent.

In the connected state, this advantageously results in improved load transfer from the holding element via the linear drive devices into the holding device due to the redundancy and increased positioning accuracy. In other words, a loading capacity of the device can advantageously be increased.

If the mechanical connection between the moving parts of the linear drive devices is released, the moving parts can move independently of one another. In the unconnected state, the number of adjustable positions and/or orientations and thus also a working space can thus advantageously be increased. In other words, the working space of the positioning device can be adjusted.

In a further embodiment, the device comprises three pairs of linear drive devices. In the case of three pairs of linear drive devices, it results in an advantageous manner that a large number of positions can be set in the unconnected state.

Furthermore, the provision of the device for positioning with pairs of linear drive devices advantageously enables the device to be configurable with regard to the number of adjustable positions and/or orientations and thus with regard to the working space. If, for example, a larger number of adjustable positions and/or orientations and thus a larger working space is desired, the mechanical connections between the moving parts of a pair of linear drive devices can be released. However, if operation with a comparatively smaller number of adjustable positions and a reduced energy requirement when operating the positioning device is desired, the moving parts can be mechanically connected and, for example, only one actuator of one of the two linear drive devices of a pair of linear drive devices can be operated, which then due to the mechanical connection jointly adjusts the positions of both movable elements of the linear drive devices along the corresponding trajectories.

Greater flexibility in the operation of the device is thus advantageously achieved.

In a further embodiment, a carriage of a first linear drive device of the pair of linear drive devices can be mechanically rigidly connected or is connected to a carriage of a second linear drive device of the pair of linear drive devices. This advantageously results in a reliable mechanical connection between the movable elements of the linear drive devices in such a way that they can perform synchronous movements.

It is also conceivable that a coupling element of a first linear drive device of the linear drive device pair can be connected or is connected to a coupling element of a second linear drive device of the linear drive device pair via an elastic connection, in particular via a spring element, e.g. a compression or tension spring. In this case, a spring element can be pretensioned. The elastic connection can be designed in such a way that the coupling elements can move freely relative to one another with selected, but not necessarily all, degrees of freedom. Furthermore, the elastic connection can be designed in such a way that the coupling elements can only move relative to one another against a spring force with at least one other selected degree of freedom.

For example, the coupling elements can be elastically connected to one another via a spring element whose spring force is oriented perpendicularly to the longitudinal axes of the coupling elements and can thus push the coupling elements apart or contract them in the direction of the acting spring force. Furthermore, the spring element can be arranged and/or designed in such a way that relative movements that are different from the movement in or against the direction of the spring force are permitted or released.

The spring force results in an advantageous manner in that a bearing play of the bearing devices, via which the coupling element is mounted on the holding element and/or on the carriage, can be reduced.

In a further embodiment, a working space of the device comprises a measuring area and a changing area, with a sensor magazine being arranged in the changing area. The working space of the device has already been explained above. The measurement area and the changeover area can refer to subareas of the working space that are different from one another. For example, it is conceivable that the changeover area forms a contiguous area of the work space that occupies 50%, 40%, 20% or 10% of the work space or less. A sensor magazine refers to a device for holding various sensors.

However, it is also possible for a sub-area of the measuring range to overlap with a sub-area of the alternating range.

In particular, it is possible to position the holding element in the changing area, in particular in the changing area, such that a sensor attached to the holding element can be inserted or introduced into the sensor magazine and/or a sensor held in the sensor magazine can be attached to the holding element.

In particular, a measurement object can be arranged in the measurement area. In particular, a measurement object holder, for example a holder designed as a turntable, can be arranged in the measurement area.

This results in an advantageous manner in that different sensors can be fastened to the holding element and used for measurement quickly and reliably.

As a result, a time period for measuring one or more measurement objects can be reduced in an advantageous manner.

In a further embodiment, the changeover area includes spatial positions of the holding element that are set when at least two carriages are in a first half of space relative to the holding element, and the measuring range includes spatial positions of the holding element that are set when at least two carriages are in another half of space relative to the holding element.

In this case, the holding element defines two halves of space, with the halves of space being separated by a parting plane which runs through a reference point of the holding element and is oriented perpendicularly to a longitudinal axis of a linear guide element. The reference point can be a focal point, a geometric center or another, clearly definable point of the holding element.

If the longitudinal axis of a linear guide element is parallel to a vertical axis, for example, the first half of the space can be arranged below the holding element and the other half of the space can be arranged above the holding element with respect to this vertical axis.

In the case of parallel kinematics, there may be the possibility that positions of the holding element that are different from one another are set or conditioned given the same sets of positions. In other words, this means that a forward calculation, that is to say the determination of the location at predetermined positions of the linear drive devices, is not unambiguous.

However, if the slides are in a certain half of space relative to the holding element, this information can be used to clearly determine the spatial position of the holding element as a function of the position set.

In the proposed embodiment, this results in an advantageous manner that both A clear forward calculation can be carried out in the change area as well as in the measuring area, which makes it easier to control the positioning device. Furthermore, the division into measuring and changing area ensures that no sensor magazine and thus no component restricting the positioning during the measurement is arranged in the measuring area.

It is possible for information about the relative arrangement between the carriage and the holding element to be determined, for example with the aid of sensors. For example, the device can comprise a rotation angle sensor for detecting a rotation angle between the carriage and the coupling element and/or a rotation angle sensor for detecting a rotation angle between the coupling element and the holding element, it being possible to determine, depending on the detected rotation angle(s), whether the carriage connected to the holding element is located in the explained first or in the explained further half of the room. Of course, other methods of determining this relative location can also be used.

It is also possible that a relationship between a position quantity of the positions of the linear drive devices and a position of the holding element in the changing area is unambiguous. A position of a linear drive device can designate a position of the movable element of the linear drive device along the linear trajectory that is assigned to the linear drive device.

Thus, for each position of the holding element in the changing area, there can only be a single set of positions of the linear drive devices, which are to be set in order to position the holding element in the respective position. In other words, a position of the holding element in the changing area cannot be adjusted with different position sets.

In the case of parallel kinematics, there may be the possibility that different sets of positions set or require the same position of the holding element. In other words, this means that a backward calculation, ie the determination of the positions of the linear drive devices for a given position, is not unambiguous.

Alternatively or cumulatively, a relationship between a position quantity of the positions of the linear drive devices and a position of the holding element is ambiguous in at least a partial area of the measuring area. This means that the measuring range includes positions of the holding element (and thus of the sensor) which can be adjusted by different sets of positions of the linear drive devices. In other words, a position of the holding element in the measurement area can be set with different position sets.

According to the invention, the device comprises a position detection device for detecting a position of the holding element or of a sensor attached to the holding element. The position of the holding element can be detected in the previously explained reference coordinate system. The position detection device enables the position of the holding element or the sensor to be detected independently of a current position of the linear drive devices or independently of information about the current position. In particular, the position detection device can directly detect the position of the holding element or the sensor. However, it is also possible to determine the position of the holding element or the sensor as a function of at least one detected variable that differs from a position of a linear drive device.

The device can thus comprise two position detection devices, namely a position detection device that detects or determines the position of the holding element or the sensor as a function of the positions of the linear drive devices, in particular via what is known as a forward calculation, and a further position detection device that detects the position independently of the current positions of the linear drive devices allows. In this case, a forward calculation denotes the determination of a position of the holding element or of the sensor as a function of the positions of the linear drive devices.

A position detection device can enable active position detection or passive position detection.

Various principles for position detection are conceivable here. For example, the position detection device can be an optical position detection device, a magnetic position detection device or a different position detection device that operates according to a further physical detection principle.

The position detection device can also be used to determine the previously explained information about the relative arrangement between the carriage and the holding element.

It is generally possible for an element of the position detection device to be arranged on the holding device. Furthermore, an element or a further element of the position detection device can be arranged on the holding element.

This results in an advantageous way that a current position of the holding element and thus also of the sensor can be detected reliably and accurately. The position detected in this way can then in turn be used to achieve increased measurement accuracy.

In particular, it is thus possible to reliably identify and, if necessary, correct incorrect movements of the linear drive devices, which therefore also affect the current position of the sensor. It is also possible to identify an error in the measurement points and to correct them if necessary.

For example, to move the sensor in a straight line, it is necessary to operate several, in particular all, linear drive devices. Incorrect movements of the individual linear drive devices are therefore superimposed to form an undesirable overall error in the positioning of the sensor. In particular, it may not be possible to determine the contribution of the movement produced by a single linear drive device to a positioning error. Due to the proposed use of a position detection device, however, such a determination is advantageously no longer necessary.

According to the invention, the position detection device is an optical position detection device. The optical position detection device can be designed as at least one image detection device, in particular as a CCD camera or CMOS camera. Furthermore, the position detection device can include at least one marker element, preferably a marker arrangement that includes a plurality of marker elements. A marker element can be designed as a two-dimensional marker element.

A marker element can have, for example, an elliptical marker body or an elliptical marker area and a geometric center of this marker body or this marker area. Here, the term "elliptical" also includes a circular configuration.

The marker body or area, which can also be referred to as the inner marker body, is filled with color spectrum points that are distributed radially with respect to the geometric center. A color value of each color spectrum point of the marker body/area can be determined depending on an angle between a horizontal line through the geometric center and another line through the geometric center and the corresponding color spectrum point. In other words, there can be an association, in particular a one-to-one association, e.g. a functional relationship, between the color spectrum value and the angle and the distance of the color spectrum point from the geometric center. The angle and distance can be given in terms of polar coordinates.

If at least two marker elements designed in this way, in particular of a target, are imaged in the image, edges of these at least two marker elements, in particular the marker body or marker areas, can be detected image-based in a further method step. In a further method step, blobs can then be detected in the set of detected edges. Blobs can denote contiguous regions in the image.

Furthermore, ellipses can be detected in the set of detected blobs. In a further method step, sinusoidal patterns can be evaluated in each detected ellipse. Furthermore, based on this evaluation, a two-dimensional position of the at least two marker elements can then be determined and then a three-dimensional position can be determined as a function of the two-dimensional dimensions.

In the necessary steps for the detection, in particular of edges, blobs, ellipses and sinusoidal patterns, image processing methods known to the person skilled in the art can be used.

Such a determination of the three-dimensional position is in the initially explained U.S. 2017/0 258 531 A1 described, reference being made in full to the corresponding disclosure. In other words, the revelation content is the U.S. 2017/0 258 531 A1 fully part of this disclosure.

In this way, a reliable and precise, but also easy to provide position detection is ensured in an advantageous manner.

According to the invention, at least one image acquisition device of the optical position acquisition device is arranged on the holding device. In particular, the image acquisition device can be arranged on the frame explained above.

In particular, the image capturing device can be arranged on the holding device in such a way that a capturing area of the image capturing device encompasses the working space of the device for positioning. It is also conceivable that the detection area covers only part of the workspace, but not the entire workspace includes. For example, the detection range can include the previously explained measurement range, but not the previously explained alternating range.

Furthermore, the image capturing device can be attached to the holding device in such a way that it is arranged outside of a working space of the device.

It is also possible for the image capturing device to be arranged on a linear guide element. Alternatively, an image acquisition device can be arranged on a connecting element for the mechanical connection of two linear guide elements. The connecting element can also be designed in the form of a rod.

It is possible for an image capturing device to be attached to the holding device in a movable, in particular linearly movable and/or rotatable manner. It is also conceivable that the device for positioning comprises at least one further actuator for setting a position of the image acquisition device, in particular relative to the holding device.

Fastening the image detection device to the holding device advantageously results in a space-reducing design of the proposed positioning device, with improved measurement accuracy being made possible at the same time due to the additional position detection device.

A position of the holding element or of the sensor, in particular in the reference coordinate system, can be detected by means of the position detection device. Position information, ie information about this position, can then be used to correct a measurement result. For example, coordinates of a measurement point can be corrected depending on the position detected by the position detection device. Alternatively or cumulatively, the position information can be used to improve the accuracy of the positioning, in particular by repositioning.

In a further embodiment, at least one marker of the optical position detection system is attached to the holding element. In particular, it is possible for a sensor to be arranged on a front or top side of the holding element and for the marker to be arranged on a back or underside of the holding element. In this case, the front side can designate a first side of the holding element and the rear side can designate a side of the holding element opposite the first side. A marker can be detachably or non-detachably attached to the holding element. If a marker is detachably attached to the holding element, the holding element can have or form attachment elements/means for attaching a marker, for example plug-in elements, latching elements, clamping elements or screw elements, for example an internal or external thread section.

A plurality of markers, in particular at least three markers, are preferably attached to the holding element. In this case, it is possible for the markers to be attached to the holding element at different positions in the coordinate system specific to the holding element. Alternatively or cumulatively, the markers can be attached to the holding element with different orientations in relation to the coordinate system specific to the holding element. It is also possible for different markers to be arranged at different distances from a surface of the holding element.

It is also possible to arrange at least one or more markers on a carriage, in particular in order—as explained above—to determine a relative arrangement between the carriage and the holding element.

It is also possible to arrange at least one or more markers on a base plate or base area of the device. This results in an advantageous manner in that a relative movement between the base plate or the base surface (and thus also a workpiece arranged thereon) and the position detection device or elements of the position detection device can also be detected. This in turn can be used, for example, to adapt a test plan and thus also to improve the measurement accuracy.

This advantageously results in a space-reducing design of the positioning device, with reliable position detection and thus—as explained above—a high measurement accuracy being ensured.

In a further embodiment, the device comprises a storage device, wherein at least one set of positions of the linear drive devices and a correction value assigned to this set of positions are stored in the storage device. Alternatively or cumulatively, at least one position of the holding element or of a sensor arranged on the holding element and a correction value assigned to this position are stored in the memory device.

The memory device can be embodied, for example, as a RAM memory device or ROM memory device or other different memory device.

A correction value assigned to a position set or a position can be determined, for example, in a calibration process, ie before (measuring) operation of the device for positioning, and stored in the memory device. The correction value can in particular encode a deviation of the actual position of the holding element, in particular in the previously explained reference coordinate system, from a target position when the positions of the position set of the linear drive devices are set or the position of the holding element is set. As already explained above in relation to the detected position, this correction value enables a correction of a measuring point and/or a correction of the set position.

If the association between a position of the holding element or a sensor attached to the holding element and a position set is not clear, at least one additional item of information can be stored in the storage device, with the further information being assigned to the position set and enabling the position to be determined unambiguously. For example, the information can encode chronologically preceding position values of the positions in the position set. The information can also encode, for example, the relative arrangement between the holding element and the carriage, as explained above. In this case, in addition to the position set, information about the spatial position of the slides relative to the holding element can also be determined and stored in the calibration process, with the correction value then being assigned to the entirety of the position set and this information.

However, it is not mandatory for the information to be stored in a memory device for unambiguous determination. The information can also be provided by a control device for controlling the linear drive devices.

The device can also include an evaluation and control device. This can in particular be designed as a computing device or include such a device. A computing device can be designed as a microcontroller or an integrated circuit, for example. By means of the evaluation and control device, one or all of the linear drive device(s) can be controlled, for example, in particular for setting a position of the linear drive device(s) and thus for setting a position of the holding element or the sensor.

Furthermore, a position of the holding element or of the sensor can be determined by means of the control and evaluation device or a different, further control and evaluation device.

Furthermore, the position correction or the correction of the measuring point can be carried out by means of the control and evaluation device or a different, further control and evaluation device.

A method for positioning a sensor or a sensor part for generating measurement points when measuring a measurement object by means of a device according to one of the embodiments described in this disclosure is also proposed. In the method, a position of each linear drive device is adjusted to position the sensor. In particular, the positioning can take place as a function of a target position of the sensor. In this case, a position of each linear drive device can be determined and set as a function of this target position. It is possible, for example, for a target position of the holding element to be determined as a function of a target position of the sensor and as a function of a previously known, for example calibrated, relationship between the target position of the sensor or a reference point of the sensor, for example a touch point The position of each linear drive device is then determined and adjusted as a function of the desired position of the holding element. The positions of the linear drive devices can be determined using the backward calculation explained above.

In particular, the position of each linear drive device can be a position of the carriage along the linear guide element explained.

If the device includes a pair of linear drive devices, the position of a linear drive device of the two linear drive devices of a pair of linear drive devices can be adjusted, in particular by correspondingly operating the actuator of one of the linear drive devices. In this case, the actuator of the remaining linear drive device cannot be operated during positioning. This is possible in particular when the linear drive devices are in the connected state.

Alternatively, it is possible, particularly in the unconnected state, but also in the connected state, to adjust the positions of both linear drive devices of a pair of linear drive devices by operating the actuators of both linear drive devices. Here, the positions can be set dependently or independently of one another. For example, the same posi tion or the same position changes can be set during positioning.

Alternatively, different positions or different position changes can be set in the positioning.

The method advantageously enables a sensor to be positioned precisely, reliably and quickly in order to generate measurement points.

In a further embodiment, the position of the holding element or of a sensor attached to the holding element is detected, in particular by means of a position detection device as explained above for detecting the position of the holding element or the sensor.

A position correction is also carried out, for example by changing the position of one or more linear drive device(s). Alternatively or cumulatively, a measurement point detected by the sensor can be corrected as a function of the detected position. This and corresponding advantages have already been explained above.

In a further embodiment, the positions of the linear drive devices are detected, with a correction value being determined which is assigned to the position set that includes these detected positions of the linear drive devices and/or with a position of the holding element and a correction value assigned to this position being determined. As explained above, this correction value and the position quantity can be stored in a memory device. Furthermore, as also already explained above, a position correction and/or a correction of a measurement point detected by the sensor is carried out as a function of the correction value.

This advantageously results in increased positioning accuracy or increased measurement accuracy when generating measurement points.

A coordinate measuring device with a device according to one of the embodiments disclosed in this disclosure is further described. The coordinate measuring device can include such a device and a sensor, the sensor being attached to the holding element of the device.

The coordinate measuring device can additionally comprise a further positioning device, for example a positioning device designed as an articulated arm robot, the holding device of the proposed device being fastened to a free end of the further positioning device. In this case, the position of the holding device of the proposed positioning device can be adjusted by the further positioning device.

The sensor, which can be attached to the holding element, can in particular be what is known as a VAST measuring head, e.g. a VAST XXT measuring head from Carl Zeiss Industrielle Messtechnik GmbH. Optical sensors can of course also be used. In particular, optical measuring heads are attached to the holding element. However, it is also possible to integrate the holding device, the linear drive devices and the holding element in one of the sensors mentioned and to fasten only one sensor part, in particular the sensor part intended for contact or the sensor part to be aligned with the measurement object for beam detection, on the holding element.

• 1 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung zur Positionierung,
• 2 eine weitere schematische Darstellung einer erfindungsgemäßen Vorrichtung zur Positionierung,
• 3a eine schematische Darstellung einer erfindungsgemäßen Vorrichtung zur Positionierung in einem ersten Bewegungszustand,
• 3b eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einem weiteren Bewegungszustand,
• 3c eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einem weiteren Bewegungszustand,
• 3d eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einem weiteren Bewegungszustand,
• 4a eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einem ersten Montagezustand,
• 4b eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einem weiteren Montagezustand,
• 5 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einer weiteren Ausführungsform,
• 6 eine schematische Darstellung eines modularen Systems mit einer erfindungsgemäßen Vorrichtung,
• 7a eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einer weiteren Ausführungsform,
• 7b eine schematische Darstellung einer erfindungsgemäßen Vorrichtung in einer weiteren Ausführungsform,
• 8 ein Flussdiagramm eines erfindungsgemäßen Verfahrens,
• 9 ein Flussdiagramm eines erfindungsgemäßen Verfahrens in einer weiteren Ausführungsform,
• 10 ein Flussdiagramm eines erfindungsgemäßen Verfahrens in einer weiteren Ausführungsform,
• 11 ein schematisches Blockdiagramm einer erfindungsgemäßen Vorrichtung.

The invention is explained in more detail using exemplary embodiments. The figures show:

• 1 a schematic representation of a device according to the invention for positioning,
• 2 a further schematic representation of a device according to the invention for positioning,
• 3a a schematic representation of a device according to the invention for positioning in a first state of movement,
• 3b a schematic representation of a device according to the invention in a further movement state,
• 3c a schematic representation of a device according to the invention in a further movement state,
• 3d a schematic representation of a device according to the invention in a further movement state,
• 4a a schematic representation of a device according to the invention in a first assembly state,
• 4b a schematic representation of a device according to the invention in a further assembly state,
• 5 a schematic representation of a device according to the invention in a further embodiment,
• 6 a schematic representation of a modular system with a device according to the invention,
• 7a a schematic representation of a device according to the invention in a further embodiment,
• 7b a schematic representation of a device according to the invention in a further embodiment,
• 8th a flowchart of a method according to the invention,
• 9 a flowchart of a method according to the invention in a further embodiment,
• 10 a flowchart of a method according to the invention in a further embodiment,
• 11 a schematic block diagram of a device according to the invention.

In the following, the same reference symbols designate elements with the same or similar technical features.

1 shows a schematic representation of a device 1 according to the invention for positioning a sensor 2 (see e.g 3a ) for generating measurement points when measuring a measurement object that is not shown. The device 1 comprises a holding device 3 for linear drive devices 6a, 6b, 6c. in the in 1 illustrated embodiment, the holding device 3 comprises a base plate 4a and a cover plate 4b. Furthermore, the holding device 3 comprises three connecting elements 5a, 5b, 5c for connecting the top and bottom plates 4a, 4b. The connecting elements 5a, 5b, 5c can be rod-shaped. These are mechanically rigidly connected both to the top panel 4b and rigidly to the bottom panel 4a. The connecting elements 5a, 5b, 5c are here arranged parallel to one another.

The connecting elements 5a, 5b, 5c each form a linear guide element of a linear drive device 6a, 6b, 6c. Each of these linear drive devices 6a, 6b, 6c comprises the respective linear guide element, ie the connecting element 5a, 5b, 5c, and a carriage 7a, 7b, 7c. The carriages 7a, 7b, 7c are in this case mounted on the linear guide elements so as to be linearly movable.

It is also shown that the device 1 comprises a holding element 8 for the sensor 2, the holding element 8 in the 1 illustrated embodiment is plate-shaped. It is also shown that each linear drive device 6a, 6b, 6c comprises coupling elements 9a1, 9a2, 9b1, 9b2, 9c1, 9c2, with the carriages 7a, 7b, 7c of the linear drive devices 6a, 6b, 6c are mechanically connected or coupled to the holding element 8.

The coupling elements 9a1, . . . , 9c2 are rod-shaped. It is shown that for each of the coupling elements 9a1, ..., 9c2, a first end of a coupling element 9a1, ..., 9c2 is mounted on the carriage 7a, 7b, 7c via a pivot bearing device, the pivot bearing device being a rotation of exactly one, exactly two or three spatial axes, which are preferably different from each other, allows.

It is also shown that a further end of each coupling element 9a1, ...., 9c2 is mounted on the holding element 8 via a further rotary bearing device, these further rotary bearing devices also being able to rotate by exactly one, exactly two or exactly three, preferably different, Enable rotation axis(s).

A reference coordinate system with a vertical axis z is also shown, it being possible for this vertical axis z to be oriented parallel and opposite to the direction of a weight force. A vertical direction is symbolized by the directional arrow of the vertical axis z. Also shown is a longitudinal axis x and a transverse axis y, these being oriented at right angles to one another and a plane spanned by the longitudinal and transverse axes being oriented perpendicular to the vertical axis z. The directional arrows of the longitudinal axis x and the transverse axis y symbolize a longitudinal direction as well as a transverse direction.

A surface of the base plate 4a and also a surface of the cover plate 4b can be oriented perpendicularly to the vertical axis z. Furthermore, the connecting elements (and thus also the linear guide elements 5a, 5b, 5c of the linear drive devices 6a, 6b, 6c) extend parallel to the vertical axis z.

To position a sensor 2, the slides 7a, 7b, 7c can be moved independently of one another along the linear guide elements 5a, 5b, 5c.

In particular, the positions of the carriages 7a, 7b, 7c along the linear guide elements 5a, 5b, 5c can be adjusted independently of one another. A position set, which includes the three positions of the carriages 7a, 7b, 7c of the linear drive devices 6a, 6b, 6c, is assigned a position, i.e. a position and/or an orientation, of the holding element 8, in particular in the reference coordinate system. If a relative position of the sensor 2 to the holding element 8, i.e. a position of the sensor 2 in a holding element-specific or holding element-fixed coordinate system, is already known, a position of the sensor 2 in the reference coordinate system is also specified via the stated position set.

Using a forward calculation, it is possible to determine the position of the holding element 8 or the sensor 2 as a function of the positions of the position set. In this case, the positions form input variables for the forward calculation mentioned, with the output variable being the position explained.

In a reverse calculation, the positions of the carriages 7a, 7b, 7c of the linear drive devices 6a, 6b, 6c can be determined as a function of a desired position. Here, the desired position forms the input variable and the positions of the position set form the output variables.

2 shows a schematic representation of a device 1 according to the invention in a further embodiment. In contrast to the in 1 In the embodiment shown, the linear drive devices 6a, 6b, 6c each comprise only one coupling element 9a, 9b, 9c for the mechanical connection of the carriages 7a, 7b, 7c to the holding element 8.

Also shown is a position pa of the carriage 7a of the first linear drive device 6a along the linear guide element 5a. Correspondingly shown is a position pb of the carriage 7b of the second linear drive device 6b along the second linear guide element 5b and a position pc of the carriage 7c of the third linear drive device 6c along the third linear guide element 5c. The position set for determining the position of the holding element 8 and thus of the sensor 2 includes the first position pa, the second position pb and the third position pc.

It is possible for the carriages 7a, 7b, 7c to be mounted on linear guide elements with air bearings.

The 3a until 3d show a schematic representation of a device 1 according to the invention for positioning a sensor 2 in different states of motion of the linear drive devices 6a, 6b, 6c, wherein in different states of motion different positions pa, pb, pc (see 2 ) of the linear drive devices 6a, 6b, 6c can be adjusted.

In the 3a , 3b , 3c and 3d The device 1 shown is like that in 2 device 1 shown is formed. In contrast to the in 2 A sensor 2 for generating measuring points is attached to the holding element 8 in the illustrated embodiment of the device. The sensor 2 can in particular be a tactile sensor for generating measurement points. In particular, the sensor 2 can include a stylus.

Also shown is a measurement area MB and a changeover area WB of a working space of the device 1. It is shown here that the changeover area WB is arranged along the vertical axis z behind the measurement area MB. In particular, the measurement area MB and the changeover area WB are separated by a parting plane 10 . A sensor magazine is arranged in the changing area WB, with further sensors 2a, 2b being able to be arranged or fastened on/in the changing magazine. It is shown here that a first additional sensor 2a is an optical sensor and a second additional sensor 2b is an additional tactile sensor with a stylus. A measurement object to be measured can be arranged in the measurement area MB.

The changeover area WB can include, in particular, spatial positions of the holding element 8, which occur when at least two carriages 7a, 7b, 7c are located in a first half of the space relative to the holding element 8, with the first half of the space being below the holding element in relation to the vertical axis z shown 8 is arranged.

The measuring range MB can include spatial positions of the holding element 8 that arise when at least two carriages 7a, 7b, 7c are located in another half of the space in relation to the vertical axis z shown above the holding element 8.

The space halves are defined by a further parting plane, which runs through a geometric center of the holding element 8 and is perpendicular to the vertical axis z.

It is possible that the changing range WB and measuring range MB overlap, in particular for sets of positions with positions pa, pb, pc of the linear drive devices 6a, 6b, 6c of the device 1, which require the same position of the holding element 8, but which are in these sets of positions resulting relative arrangements between carriage 7a, 7b, 7c and holding element 8 with respect to the space halves explained are different from each other.

In the 3a until 3d shows how the holding element 8 with the sensor 2 attached to it is moved from the measuring area MB to the changing area WB in order to exchange the sensor 2 currently attached to the holding element, i.e. to attach it to the sensor magazine and to accommodate one of the other sensors 2a, 2b .

In 3a is a motion initial state in which 3b , 3c an intermediate state and in 3d a final state is shown.

It is shown here that a relationship between a position set with positions pa, pb, pc of the linear drive devices 6a, 6b, 6c of the device 1 and a position of the holding element 8 in the measuring area can be ambiguous, in particular for a position in the measuring area MB. In particular, in 3a and 3c a state of movement of the device 1 is shown in each case, in which the holding element 8 assumes the same position or is positioned in the same position, but the positions pa, pb, pc of the two position sets for setting this position differ from one another.

In order to remove the holding element 8 from the 3a shown initial movement state of the linear drive devices 6a, 6b, 6c, in which the holding element 8 is arranged in the measuring area MB, into the changing area WB, the holding element 8 is moved by operating and positioning the linear drive devices 6a, 6b, 6c, in particular by moving the carriage 7a , 7b, 7c (see 2 ), along the linear guide elements 5a, 5b, 5c in the in 3b shown movement (intermediate) state transferred, wherein the position of the holding element 8 changes. From this first intermediate movement state, the holding element 8 can then move into the same position as in 3a shown initial state of motion are transferred, but the state of motion of the linear drive devices 6a, 6b, 6c, in particular the positions pa, pb, pc of the position set of the linear drive devices 6a, 6b, 6c in this further intermediate movement state from the positions pa, pb, pc of the in 3a shown movement (initial) state are different. Thereafter, the holding element 8 can be moved from the measuring area MB to the changing area WB, with 3d a movement end state is shown, in which the holding element 8 is arranged with the sensor 2 in the changing area WB.

The device 1 can thus be designed in such a way that a movement of the holding element 8 from the measuring area MB to the changing area WB is only possible from one of two sets of positions that are different from one another, with the two sets of positions being assigned the same position of the holding element 8, i.e. that Retaining element 8 occupies the same position when setting the positions pa, pb, pc of these position sets.

The device 1 can also be designed in such a way that the holding element 8 can only be moved from a position in the measuring area, to which different position sets are assigned, from a movement state with a first position set into the change area by during the movement a movement state with a further Position quantity of the different position quantities is adjusted.

This can be clearly described as “folding over” the linear drive devices, in particular the moving parts of the linear drive devices. This advantageously results in a division into measuring area MB and changeover area WB, secured by the kinematic structure of the device, and also the possibility of arranging a changeover area WB with a sensor magazine in the vertical direction z above/below the measurement area MB, which in turn means that there is no space in the measurement area MB, in particular along directions transverse to the vertical direction z, is required in order to arrange sensors to be replaced or replaced there. A desired size of the measurement area, in particular along the directions mentioned, can be ensured from this.

The arrows in 3b , 3c , 3d represent the respective directions of movement of the linear drive devices, in particular the movable elements of the linear drive devices 6a, 6b, 6c, in which these movable elements must be moved in order to assume the movement states shown in these figures.

4a shows a schematic representation of a device 1 according to the invention in a further embodiment in a first assembly state. In contrast to the in 1 In the illustrated embodiment, the device 1 comprises three linear guide elements 5a, 5b, 5c for guiding the movement of carriages 7a, 7b, 7c. These linear guide elements 5a, 5b, 5c are in turn mechanically rigidly connected to one another by connecting elements 11. The connecting elements 11 for the mechanical connection of the linear guide elements 5a, 5b, 5c can also be rod-shaped. In 4a shows that a bottom surface of the device 1 for mounting the device 1 on a foundation is formed by a first linear guide element 5a, a second linear guide element 5b and by the two connecting elements 11, which connect the different ends of the two linear guide elements 5a, 5b to one another. In 4b is a schematic representation of a device 1 according to the invention in a further assembly state, the device 1 corresponding to the 4a device shown is formed. In contrast to the in 4a Device 1 shown is the bottom surface by connecting elements 11 for connecting the Linearfüh tion elements 5a, 5b, 5c and not formed by linear guide elements 5a, 5b, 5c.

In the 4a and 4b The device 1 shown advantageously makes it possible to provide different working spaces in relation to a common coordinate system, in particular a reference coordinate system. Thus, the point of the device 1 in the in 4a The working space provided in the assembly state shown has a greater length along the longitudinal axis x than that of the device 1 in the 4b shown assembly state. Accordingly, the working space of the device 1 in the in 4b assembly state shown has a greater height along the vertical axis z than the working space of the device 1 in the 4a shown assembly state.

This advantageously makes it possible to adapt a working space to a measurement task, in particular a measurement object to be measured.

5 shows a schematic representation of a device 1 according to the invention in a further embodiment. Shown is a base plate 4a. It is also shown that the device 1 comprises three pairs of linear drive devices. A first pair of linear drive devices includes a first linear drive device 6a1 and a second linear drive device 6a2, each of which includes a linear guide element 5a1, 5a2 and a carriage 7a1, 7a2. Correspondingly, a second pair of linear drive devices comprises a first linear drive device 6b1 and a second linear drive device 6b2, which likewise each have a linear guide element 5b1, 5b2 and a carriage 7b1, 7b2. A third pair of linear drive devices includes a first linear drive device 6c1 and a second linear drive device 6c2, each of which in turn includes a linear guide element 5c1, 5c2 and a carriage 7c1, 7c2.

It is shown that the linear guide elements 5a1, 5a2, 5b1, 5b2, 5c1, 5c2 are arranged parallel to one another. These linear guide elements 5a1, ..., 5c2 also extend parallel to the vertical axis z. It is also shown that a minimum distance connecting line between the linear guide elements 5a1, 5a2, .

It is also shown that the carriage 7a1 of the first linear drive device 6a1 of the first pair of linear drive devices is mechanically connected to the holding element 8 via a first coupling element 9a1. As already explained above, the coupling element 9a1 can be mounted both on the carriage 7a1 and on the holding element 8 via rotary bearing devices. Correspondingly, the carriages 7a2, . . . 7c2 of the linear drive devices 6a2, .

At least one movable part of the first linear drive device 6a1 of the first pair of linear drive devices can be mechanically rigidly connected to a movable part of the second linear drive device 6a2 of this first pair of linear drive devices. For example, carriages 7a1, 7a2 of these linear drive devices 6a1, 6a2 can be mechanically rigidly connected or connected to one another. Alternatively or cumulatively, coupling elements 9a1, 9a2 of these linear drive devices 6a1, 6a2 can be mechanically rigidly connected to one another.

Correspondingly, the movable elements of the linear drive devices 6b1, 6b2, 6c1, 6c2 of the other pairs of linear drive devices can also be mechanically rigidly connected or connected to one another.

In a mechanically connected state, it is possible that an actuator of only one of the two linear drive devices 6a1, ..., 6c2 of a pair of linear drive devices is operated in order to achieve a desired position of the two movable elements, i.e. carriages 7a1, ..., 7c2, of a pair of linear drive devices set. Alternatively, however, it is of course also possible to operate actuators of both linear drive devices 6a1, . . . , 6c2 to set a desired position.

In a mechanically unconnected state, the positions of the movable members of the linear actuators 6a1, ..., 6c2 can be adjusted independently of each other. This advantageously results in an increase in the working space, ie the number of adjustable positions and orientations.

In 5 a detailed section of the holding element 8 surrounded by a dashed circle is also shown. A coordinate system specific to the holding element or fixed to the holding element is shown here, which comprises a vertical axis z8, a longitudinal axis x8 and a transverse axis y8. The axes x8, y8, z8 are oriented perpendicular to each other. Curved arrows show that by adjusting the positions of the movable elements of the linear drive devices 6a1, ..., 6c2, the holding element 8 can be moved around the axes x8, y8, z8 and along these axes x8, y8, z8.

6 shows a schematic representation of a modular measuring system with an invention according device 1. The system can form a coordinate measuring device. This in 6 The system shown includes a further positioning device 12, which can be designed, for example, as an articulated arm robot. The proposed device 1 for positioning a sensor 2 can be arranged at an end effector interface 13 of the articulated arm robot. For example, a base plate 4a of the device 1 can be attached to the end effector interface 13, for example screwed or flanged on. Furthermore, a sensor 2, for example a tactile sensor, can be attached to the holding element 8 of the device 1.

What is not shown is that the device 1 can be part of the sensor 2 or can be built into it and can therefore be used to position the feeler ball of the sensor 2 shown. In this case, the sensor 2 can be arranged at the end effector interface 13 of the further positioning device 12, in particular the holding device 3. The feeler ball or a feeler with a feeler ball can also be attached to the holding element 8.

7a shows a schematic representation of a device 1 according to the invention in a further embodiment. Here the in 7a shown device according to in 1 device 1 shown is formed. In contrast to the in 1 illustrated embodiment includes in 7a illustrated embodiment of the device 1 no cover plate 4b (see 1 ), but a cover ring 14 for the mechanical connection of linear guide elements 5a, 5b, 5c. The cover ring 14 forms part of the holding device 3 of the device 1.

Of course, forms of construction that differ from the construction as a cover ring 14 are also conceivable.

It is also shown that the device 1 includes a position detection device for detecting a position of the holding element 8, in particular in the reference coordinate system. The position detection device is designed as an optical position detection device and includes a number of image detection devices 15 and a number of optically detectable markers 16 which form a marker arrangement.

It shows that the image capturing devices 15 , which can be in the form of cameras, in particular CMOS or CCD cameras, for example, are fastened or mounted on the holding device 3 . In particular, the image acquisition devices 15 can be attached to the cover ring 14, ie a connecting element for the mechanical connection of linear guide elements 5a, b, 5c. Alternatively or cumulatively, image acquisition devices 15 can be attached to a linear guide element 5a, 5b, 5c. However, image acquisition devices 15 are preferably arranged on the connecting element, but not on a linear guide element 5a, 5b, 5c.

The markers 16 of the marker arrangement can be optically detected by the image detection devices 15, ie can be imaged in preferably two-dimensional images. The position of the markers 16 or of the marker arrangement formed by the markers 16 and thus also the position of the holding element 8 can then be determined from a control device 17, which can be designed, for example, as a microcontroller or integrated circuit, depending on the generated images. The image acquisition devices 15 are arranged accordingly.

It is thus possible to determine the position of the holding element 8 and thus also of a sensor 2 attached to the holding element 8 independently of the position values of the positions pa, pb, pc of the linear drive devices 6a, 6b, 6c (see 1 and 2 ) to determine. In other words, a position of the holding element 8 and thus also of a sensor 2 attached thereto can be determined independently of a forward calculation.

It is possible, depending on the position of the holding element 8 detected by the position detection device, to determine a deviation of the actual position of the holding element 8 (which is detected/determined by the position detection device) from a target position. This deviation can then be used for correction. In particular, a position control of the positions of the linear drive devices 6a, 6b, 6c (see 1 and 2 ) be carried out in such a way that the deviation of the actual position from the target position is minimized. Alternatively or cumulatively, a measured value generated by the sensor 2, for example coordinates of a measuring point, can be corrected depending on the deviation between the actual position and the target position. In particular, the measured value can be corrected in such a way that the coordinates of the measuring point correspond to the actual coordinates of the sensor 2 or the touch point.

7b shows a schematic representation of a device 1 according to the invention in a further embodiment. The device 1 is in accordance with the in 7a embodiment shown formed. In contrast to the in 7a illustrated embodiment, the device 1 includes no position detection device and thus no image detection devices 15. In 7b here the device 1 is shown in a calibration state. In the calibration state can a calibration element, in particular a calibration element 18 designed as a calibration plate, can be fastened to a stationary part of the device 1, for example the base plate 4a. An image capturing device 19 , for example also a camera, can be fastened to the holding element 8 . Calibration marks can be arranged on the calibration element 18, which can be detected optically and which have a previously known spatial arrangement relative to one another.

During the calibration process, the holding element 8 with the image acquisition device 19 arranged thereon can be moved into different positions. In this case, a target position is specified and, for example via backward calculation, an item quantity for setting the target position is determined. After setting the positions pa, pb, pc (see 2 ) of this item quantity then an actual situation arises. Due to tolerances and environmental influences, however, the actual position can deviate from the target position. In each of the positions set in this way, an image of the calibration element 18 can be generated by means of the image acquisition device 19 . Image processing methods known to those skilled in the art can then be used to determine an image-based deviation of the actual position from which the image was generated from the target position, in particular by comparing the image generated from the actual position with a computer-determined/simulated one target image generated from the target position.

As explained above, this deviation can then be used as a correction value in a subsequent measuring operation, for example for position control and/or for measuring point correction.

8th shows a schematic flow chart of a method according to the invention for positioning a sensor 2 (see e.g 3a ). A target position of the sensor 2 is determined in a first step S1. Furthermore, in the first step S1, a position set of positions pa, pb, pc of the linear drive devices 6a, 6b, 6c of a proposed device 1 (see e.g 1 ) are determined, which are associated with this target position.

In a second step S2, a corresponding position pa, pb, pc of the linear drive devices 6a, 6b, 6c can then be set.

9 shows a schematic flow diagram of a method according to the invention in a further embodiment. This in 9 The method shown here comprises three steps S1, S2, S3, with the first two steps S1, S2 in 8th correspond to steps S1, S2 shown. In a third step S3, an actual position of the sensor 2 is determined by means of a position detection device. In a fourth step S4, a deviation between the actual position and the target position explained above can then be determined and, as also explained above, a correction of the positions pa, pb, pc of the linear drive devices 6a, 6b, 6c and/or a Correction of the measured value generated by sensor 2 can be carried out.

10 shows a flowchart of a method according to the invention in a further embodiment. like that in 9 The method illustrated in 10 Method shown four method steps S1, S2, S3, S4. In contrast to the in 9 In the embodiment shown, a correction value is determined in a third step S3 as a function of the target position or as a function of a number of set positions pa, pb, pc of the linear drive devices 6a, 6b, 6c, for example retrieved from a storage device, with different positions in the storage device or different position sets and correction values assigned to these different positions are stored. In a fourth step S4, the correction value can then be used to correct the position and/or to correct the measured value.

11 shows a schematic block diagram of a device 1 according to the invention 11 illustrated embodiment, a control and evaluation device 20 of the device 1 is shown. This is signal and / or data technology with the linear drive devices 6a, 6b, 6c (see e.g 1 ), In particular with actuators of these linear drive devices 6a, 6b, 6c connected. By means of the control and evaluation device 20, the linear drive devices 6a, 6b, 6c can be operated, in particular desired positions can be set. For this purpose, the control and evaluation device 20, which can be embodied as a microcontroller or an integrated circuit, for example, can determine target positions of the linear drive devices 6a, 6b, 6c as a function of a target position of a sensor 2 and can generate corresponding control signals for operating the actuators of the linear drive devices 6a, 6b , 6c generate.

Also shown is a position detection device 21, which can also be connected to the control and evaluation device 20 in terms of signals and/or data. In this case, the position detection device 21 can comprise a further evaluation device, which can likewise be designed as a microcontroller or integrated circuit, for example. By means of the position detection device 21 is an actual position of the holding element 8 or a sensor 2 attached to the holding element 8 can be determined. This can then be transmitted to the control and evaluation device 20 . Furthermore, a position correction and/or a correction of a measured value generated by the sensor 2 can then be carried out by means of the control and evaluation device 20 .

Alternatively or cumulatively, the device 1 can have an in 11 storage device 22 shown in dashed lines, with storage device 22 storing positions of holding element 8 or sensor 2 and correction values assigned to these positions or sets of positions pa, pb, pc of linear drive devices 6a, 6b, 6c and correction values assigned to these sets of positions. These can then be called up during operation by the control and evaluation device 20 in order—as already explained above—to carry out a position correction and/or a correction of a measured value generated.

Claims (14)

Device for positioning a sensor (2) or sensor part for generating measurement points when measuring a measurement object, the device (1) having at least one holding device (3) for linear drive devices (6a, 6b, 6c, 6a1,..., 6c2), comprises a first, a second and at least a third linear drive device (6a, 6b, 6c) and at least one holding element (8) for the sensor (2), each of the linear drive devices (6a, 6b, 6c, 6a1,..., 6c2 ) is mounted on the holding device (3), with part of the linear drive device (6a, 6b, 6c, 6a1,..., 6c2) forming part of the holding device (3), with each of the linear drive devices (6a, 6b, 6c, 6a1,...,6c2) is mechanically connected to the holding element (8), characterized in that the device has at least one position detection device (21) for detecting a position of the holding element (8) or a sensor ( 2) comprises the position detection device (21) being an optical position detection device (21), at least one image detection device (15) of the optical position detection device (21) being arranged on the holding device (3). device after claim 1 , characterized in that a linear drive device (6a, 6b, 6c, 6a1, ..., 6c2), a linear guide element (5a, 5b, 5c, 5a1, ..., 5c2) and a carriage (7a, 7b, 7c, 7a1,. .., 7c2), which is linearly movably mounted on the linear guide element (5a, 5b, 5c, 5a1, ..., 5c2). device after claim 2 , characterized in that a linear drive device (6a, 6b, 6c, 6a1,..., 6c2) has a coupling element (9a, 9b, 9c, 9a1,..., 9c2) for connecting the carriage (7a, 7b, 7c, 7a1,...,7c2) and the holding element (8). device after claim 2 or 3 , characterized in that a carriage (7a, 7b, 7c, 7a1,..., 7c2) is mounted on the linear guide element (5a, 5b, 5c, 5a1,..., 5c2) via an air bearing device. Device according to one of the preceding claims, characterized in that the device (1) comprises at least one pair of linear drive devices with two linear drive devices (6a1, 6a2, 6b1, 6b2, 6c1, 6c2), at least one movable element of a first linear drive device (6a1, 6b1, 6c1) of the pair of linear drive devices can be mechanically rigidly connected or is connected to a movable element of a second linear drive device (6a2, 6b2, 6c2) of the pair of linear drive devices. device after claim 5 , characterized in that the device (1) comprises three linear drive device pairs. device after claim 5 or 6 , characterized in that a slide (7a1, 7b1, 7c1) of a first linear drive device (6a1, 6b1, 6c1) of the linear drive device pair is mechanically rigid with a slide (7a2, 7b2, 7c2) of a second linear drive device (6a2, 6b2, 6c2) of the linear drive device pair can be connected or is connected and/or that a coupling element (9a1, 9b1, 9c1) of a first linear drive device (6a1, 6b1, 6c1) of the pair of linear drive devices is mechanically rigid with a coupling element (9a2, 9b2, 9c2) of a second linear drive device (6a2, 6b2, 6c2 ) of the pair of linear drive devices can be connected or is connected. Device according to one of the preceding claims, characterized in that a working space of the device comprises a measuring area (MB) and a changing area (WB), a sensor magazine being arranged in the changing area (WB). device after claim 8 , characterized in that the changing area (WB) comprises spatial positions of the holding element (8) which are set when at least two carriages (7a, 7b, 7c, 7a1,..., 7c2) are in a first half of space relative to the holding element ( 8) are located, and the measuring range (MB) includes spatial positions of the holding element (8) that arise when at least two carriages (7a, 7b, 7c, 7a1, ..., 7c2) in one another half of the room relative to the holding element (8) are located. Device according to one of the preceding claims, characterized in that at least one marker (16) of the optical position detection system is attached to the holding element (8). Device according to one of the preceding claims, characterized in that the device comprises a storage device (22), in which storage device (22) at least one set of positions (pa, pb, pc) of the linear drive devices (6a, 6b, 6c, 6a1, ...,6c2) and a correction value assigned to this position set and/or at least one position of the holding element (8) or a sensor (2) arranged on the holding element (8) and a correction value assigned to this position are stored. Method for positioning a sensor (2) or sensor part for generating measurement points when measuring a measurement object by means of a device (1) according to one of Claims 1 until 11 , wherein a position (pa, pb, pc) of each linear driving means (6a, 6b, 6c, 6a1,..., 6c2) is adjusted. procedure after claim 12 , characterized in that the position of the holding element (8) or of a sensor (2) attached to the holding element (8) is detected, with a position correction and/or a correction of a measuring point detected by the sensor (2) depending on the detected position is carried out. procedure after Claim 13 , characterized in that the positions (pa, pb, pc) of the linear drive devices (6a, 6b, 6c, 6a1,...,6c2) are detected, with a correction value being determined which corresponds to the position set that these detected positions (pa , pb, pc) and/or a position of the holding element (8) and a correction value assigned to this position being determined, with a position correction and/or a correction of a measuring point detected by the sensor (2) depending on the correction value is carried out.

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