measuring device

Abstract

A method (74) for controlling a measuring device (10) for determining dimensional and / or geometric properties of a measurement object (16), wherein the measuring device (10) has a measurement object holder (14) and a measuring sensor (12), wherein the measuring sensor (12) defines a reference point (62) for measuring the measurement object (16) and is movable within a measurement volume relative to the measurement object holder (14) along a plurality of movement axes (X, Y, Z, A, B, C) for measuring a plurality of measurement points (56) of the measurement object (16), comprising the steps of: (i) determining a plurality of permissible measurement directions of the measuring sensor (12) for each of the plurality of measurement points (56) based on a desired measurement direction (58) for the respective measurement point (56), wherein the plurality of permissible measurement directions (76) maintain a measurement direction tolerance with respect to the desired measurement direction (58),and / or determining a plurality of permissible measuring positions (84) of the measuring sensor (12) for each of the plurality of measuring points (56) based on a reference point target position (60) for the reference point (62) for the respective measuring point (56), wherein, in the plurality of permissible measuring positions (84) of the measuring sensor (12), the reference point (62) maintains a position tolerance with respect to the reference point target position (60), (ii) determining a plurality of permissible axis positions (86) of at least one movement axis (X, Y, Z, A, B, C) of the plurality of movement axes (X, Y, Z, A, B, C) for each of the plurality of measuring points (56) based on the permissible measuring directions (76) and / or the permissible measuring positions (84) for the respective measuring point (56), and (iii) determining an optimal axis position (94) of the at least one movement axis (X, Y, Z, AWAY,C) for each of the plurality of measuring points (56) from the plurality of permissible axis positions (86) previously determined for the respective measuring point (56) in order to optimize the movement of the measuring sensor (12) in the measuring volume.,

Description

[0001] The present invention relates to a method for controlling a measuring device for determining dimensional and / or geometric properties of a measurement object. Furthermore, the present invention relates to a computer program product with program code configured to execute the inventive method. The invention further relates to a measuring device for determining dimensional and / or geometric properties of a measurement object.

[0002] Examples of such measuring devices are coordinate measuring machines or roughness measuring machines.

[0003] Coordinate measuring machines are used, for example, to check the geometry of a workpiece as part of quality assurance or to determine the geometry of a workpiece (e.g., in the context of reverse engineering). A method for controlling a coordinate measuring machine and a coordinate measuring machine are known, for example, from DE 10 2019 110 508 A1.

[0004] Coordinate measuring machines use various types of sensors to capture the dimensional and geometric properties of the measuring object. Coordinate measuring machines' sensors can generally be divided into tactile and optical sensors. Coordinate measuring machines that use both tactile and optical sensors are also referred to as "multi-sensor coordinate measuring machines."

[0005] With tactile sensors, the surface of the measuring object is scanned either selectively by touching it or continuously using a stylus or stylus ball as part of a scanning process. The probe is positioned at each measuring point. Additionally or alternatively, a rotary table can be used, for example, to move the measuring object relative to the probe. Tactile sensors advantageously enable relatively high measurement accuracy. An example of a tactile sensor is the sensor marketed by the applicant under the product name "VAST XT" or "VAST XXT."

[0006] Optical sensors, for example, utilize the triangulation principle, such as structured light projectors. A light source, such as a laser diode, generates light on the surface of the object being measured, and an image sensor (or camera sensor) detects the light reflected from the surface of the object being measured. This allows conclusions to be drawn about the dimensional or geometric properties of the object being measured. Advantageously, optical sensors enable non-contact measurement, a relatively high measurement speed, and complete surface coverage of the object being measured.

[0007] An example of an optical measuring sensor is the optical sensor marketed by the applicant under the product name "ViScan." Another measuring sensor, which uses a laser line projected onto the measurement object to determine coordinate measurements based on the triangulation principle, is offered by the applicant under the name "EagleEye II" for quality assurance in the production of motor vehicle bodies.

[0008] An example of measuring software that can be used to measure workpieces with a coordinate measuring machine is the CALIGO measuring software with MultiX technology distributed by the applicant, which can be combined, for example, with the EagleEye II sensor.

[0009] To position the measuring object relative to the measuring head, coordinate measuring machines typically use electrically operated positioning devices that move the measuring sensor and the measuring object holder relative to each other. Depending on the design of the coordinate measuring machine, the measuring sensor and / or the measuring object holder, for example a measuring table, are actively moved. The movement usually occurs along three, perpendicular axes of movement. In certain designs, both the measuring sensor and the measuring object holder or the measuring table are moved. In the so-called cantilever design, the measuring table is usually moved along one movement axis and the measuring sensor along two perpendicular axes of movement.In coordinate measuring machines with a cross-table design, the measuring table can be moved along two orthogonally aligned axes, whereas the measuring sensor can usually only be moved along one axis. In bridge, gantry, and column designs, the measuring sensor can usually be moved along three orthogonally aligned axes. The workpiece holder is often located at a fixed position in space.

[0010] The control of the positioning device for an automated measurement of the measuring object along a plurality of measuring points can be carried out based on predetermined coordinates of the measuring points and a respective target measuring direction in which the measuring sensor is to measure.

[0011] An exemplary control of the positioning devices of a coordinate measuring machine is known from the aforementioned DE 10 2019 110 508 A1.

[0012] With such a control of the positioning devices of a coordinate measuring machine, it is often problematic that, when measuring a workpiece, relatively many and / or large axis changes are sometimes necessary in order to move the measuring sensor from one measuring position to a subsequent measuring position using the movement axes or to align the measuring sensor from one measuring point to another according to a measuring direction. Due to the kinematic properties / limitations of the individual sensor axes, many angular changes of the sensor axes are sometimes necessary in order to get from one specified measuring orientation to the next. For example, even a relatively small change in the target measuring direction can result in a relatively large change in the rotation axis. Since moving the measuring sensor along the movement axes requires time, such large axis changes often have a negative effect, i.e.extending, on the total time required to measure the measurement object.

[0013] It is therefore an object of the present invention to provide a method for controlling a measuring device for determining dimensional and / or geometric properties, software for carrying out the method and a measuring device for determining dimensional and / or geometric properties, which enable efficient control of the movement of the measuring sensor, in particular for automated measurement of the measuring object.

[0014] This object is achieved according to the invention by the method according to claim 1 for controlling a measuring device for determining dimensional and / or geometric properties of a measurement object, wherein the measuring device has a measurement object holder and a measuring sensor, wherein the measuring sensor defines a reference point for measuring the measurement object and is movable within a measuring volume relative to the measurement object holder along a plurality of movement axes for measuring a plurality of measuring points of the measurement object, and the method comprises the following steps: (i) Determining a plurality of permissible measuring directions of the measuring sensor for each of the plurality of measuring points based on a target measuring direction for the respective measuring point, wherein the plurality of permissible measuring directions maintain a measuring direction tolerance with respect to the target measuring direction, and / or Determining a plurality of permissible measuring positions of the measuring sensor for each of the plurality of measuring points based on a reference point target position for the reference point for the respective measuring point, wherein in the plurality of permissible measuring positions of the measuring sensor, the reference point maintains a position tolerance with respect to the reference point target position, (ii) determining a plurality of permissible axis positions of at least one movement axis of the plurality of movement axes for each of the plurality of measuring points based on the permissible measuring directions and / or the permissible measuring positions for the respective measuring point, and (iii) Determining an optimal axis position of the at least one movement axis for each of the plurality of measuring points from the plurality of permissible axis positions previously determined for the respective measuring point in order to optimize the movement of the measuring sensor in the measuring volume.

[0015] The present invention is based on the idea of ​​utilizing a measuring range of the measuring sensor that is adequately suited for measuring. According to the invention, it is advantageously not necessary to align the measuring sensor for each measuring point precisely according to the desired measuring direction and / or the desired reference point position. Instead, the optimal axis position of at least one movement axis is determined while maintaining a measuring direction tolerance and / or a position tolerance. Thus, the movement of the measuring sensor can be improved without significantly compromising the measuring accuracy, while simultaneously fulfilling a measuring task with the required measuring accuracy.

[0016] According to the method according to the invention for controlling the measuring device, the plurality of permissible measuring directions and / or the plurality of permissible measuring positions for the measuring sensor are first determined for each of the plurality of measuring points. In the subsequent step, which is also referred to as direct kinematics, the plurality of permissible axis positions of the at least one movement axis are determined for each of the plurality of measuring points based on the previously determined plurality of permissible measuring directions and / or the previously determined plurality of permissible measuring positions. In the subsequent step, an optimal axis position of the at least one movement axis is selected for each of the plurality of measuring points from the previously determined plurality of permissible axis positions.

[0017] Which of the plurality of permissible axis positions is the optimal axis position can depend on the respective permissible axis positions of the at least one movement axis for the other of the plurality of measuring points. In particular, the optimal axis position can depend on the order in which the plurality of measuring points are arranged. The optimization of the axis position of the at least one movement axis can be carried out independently of the other of the plurality of movement axes.

[0018] Thus, the method according to the invention makes it possible to achieve optimal utilization of the dynamic range of a measuring sensor and thereby improve the measuring speed without significantly impairing the measuring accuracy.

[0019] The above-mentioned task has thus been completely solved.

[0020] The term “multiplicity” (e.g. of measuring points, of movement axes) in this case means a number of exactly two or more.

[0021] The measuring device is preferably a coordinate measuring machine and / or a roughness measuring machine.

[0022] The measuring sensor defines a reference point for measuring the measuring object. For an exact measurement, the measuring sensor is moved so that the reference point lies at the respective measuring point of the measuring object, the reference point target position. The reference point is a point that is preferably fixed in relation to a body-fixed coordinate system of the measuring sensor. Due to a fixed geometric relationship between the reference point and the measuring sensor, the measuring position of the measuring sensor is determined by the position of the reference point and vice versa. For example, the reference point lies on an axis of the measuring sensor, which corresponds, for example, to the measuring direction of the measuring sensor. The reference point can be arranged inside the measuring sensor (e.g. a tactile measuring sensor) or outside the measuring sensor (e.g. an optical measuring sensor).

[0023] For optical sensors, the reference point can be a tool center point (TCP) (sometimes also referred to as the tool center point). For an optical sensor with an image sensor element and a laser element as the light source, the tool center point can, for example, be at the focus of the laser element and the focus of the image sensor element. If the laser element projects a line of light onto the surface of the measuring object (as with a structured light projector, for example), the tool center point can be in the center of the projected laser line. The reference point for tactile sensors can, for example, be located at the end of the stylus that contacts the surface of the measuring object (e.g., a sphere center point of a stylus).

[0024] The plurality of measuring points can define a measuring path with a defined sequence of the plurality of measuring points, along which the reference point of the measuring sensor is to be moved.

[0025] Each of the plurality of measuring points is characterized by the respective target measuring direction and / or the respective reference point target position. The target measuring direction and / or the reference point target position can, for example, be specified by a user or determined (in particular received) by the measuring device.

[0026] The target measuring direction is the direction in which the measuring sensor is intended to measure. For an optical measuring sensor with an image sensor element and a laser element, the target measuring direction corresponds, for example, to a laser beam axis that runs through the laser element and the respective measuring point. Alternatively, the measuring direction can correspond to an axis that runs through the image sensor element and the respective measuring point. For a tactile measuring sensor, the target measuring direction can correspond to an axis of the probe element.

[0027] The measurement direction tolerance and the position tolerance refer to tolerances that relate to the suitable measuring range of the measuring sensor, which is also referred to here as the "dynamic range" of the measuring sensor. It is understood that these tolerances do not refer to inaccuracies within the scope of technically given positioning inaccuracies of the measuring sensor.

[0028] The measurement direction tolerance can be specified, for example, by a value range for an angle or a function that defines the value range. The value range specifies the angle at which the permissible measurement direction may be oriented relative to the nominal measurement direction. It is understood that the multitude of permissible measurement orientations includes the nominal measurement direction of the respective measuring point.

[0029] The position tolerance can be specified by a value range or a function that defines the value range. The value range specifies the value by which the measuring position of the measuring sensor or the reference point of the measuring sensor may deviate from the reference point target position in one or more directions. The maximum permissible deviation can vary depending on the direction. In general, the position tolerance can define a regular or irregular three-dimensional shape that maps a subset of the measurement volume for each reference point, where the subset includes the reference point target position.

[0030] For tactile sensors, the position tolerance can be adjusted to prevent collisions between the measuring sensor or probe element and the measurement object. The position tolerance can, for example, be a two-dimensional shape. For example, the position tolerance can lie in a plane, with the normal of the plane orthogonal to the surface of the measurement object at the reference point. Alternatively, the position tolerance can be zero (no measurement position tolerance).

[0031] The determination of the permissible measuring positions can be carried out, particularly in the case of optical sensors, taking into account the (global) geometry of the measuring object in order to avoid collisions between the measuring sensor and the measuring object (e.g. in the case of relatively complex geometries).

[0032] It is understood that the measurement direction tolerance and / or the position tolerance can vary from measurement point to measurement point. For example, the measurement direction tolerance and / or the position tolerance can be specified (e.g., by a user) for sections of the measurement object or sections along the measurement path.

[0033] From the measuring direction and position of the measuring sensor, the corresponding axis positions of the numerous motion axes can be calculated using "direct kinematics." Conversely, the specified axis positions of the numerous motion axes determine the measuring direction and / or the measuring position of the measuring sensor. The axis position can be determined by axis values, such as rotation angle values ​​for a rotary axis and linear axis values ​​for a linear axis.

[0034] The plurality of movement axes may have at least one rotational axis and / or at least one linear axis.

[0035] According to one embodiment, the target measuring direction and the plurality of permissible measuring directions for the respective measuring point pass through a common point.

[0036] The common point can be the respective measuring point of the measuring object or the reference point of the measuring sensor.

[0037] Advantageously, the reference point of the measuring sensor can be located at the measuring point or at the reference point target position for each of the permissible measuring directions. This can have a positive effect on measurement accuracy.

[0038] The measurement direction tolerance can define a two-dimensional or three-dimensional envelope that encloses and limits the permissible measurement directions. For example, the envelope has the shape of a pyramid or any free form in space.

[0039] According to another embodiment, the permissible measuring directions for the respective measuring point lie within a defined enveloping cone around the desired measuring direction.

[0040] Advantageously, the permissible measurement directions can be evenly distributed or discretized within the enveloping cone. Thus, with a reasonable computational effort, a large number of uniformly differently oriented permissible measurement directions can be included in the optimization. This allows an adequate "search area" for an optimal measurement direction or an optimal axis position of at least one motion axis to be covered.

[0041] Preferably, the enveloping cone has a half opening angle of less than or equal to 80°, less than or equal to 70°, less than or equal to 60°, less than or equal to 50°, less than or equal to 40°, less than or equal to 30°, less than or equal to 20°, less than or equal to 10° or less than or equal to 5°. The half opening angle of the enveloping cone is defined by the angle between one of the surface lines and an axis of symmetry of the enveloping cone.

[0042] In the present case, the optimal measuring direction refers to a measuring direction of the measuring sensor which is predetermined by the optimal axial position of the at least one movement axis determined in step (iii), wherein the at least one movement axis is in particular a rotation axis.

[0043] Preferably, the target measuring direction is the symmetry axis of the enveloping cone. The permissible measuring directions can then each enclose an angle with the target measuring direction that is less than or equal to the measuring direction tolerance. Advantageously, the permissible measuring directions can thus be evenly distributed around the target measuring direction.

[0044] According to a further embodiment, in the plurality of permissible measuring positions of the measuring sensor, the reference point lies in a plane with the respective reference point target position.

[0045] This has the advantage that, with a reasonable computational effort, a large number of different permissible measurement positions can be included in the optimization (corresponding to an “adequate search range”).

[0046] Preferably, the permissible measurement positions are evenly distributed in the plane according to a uniform discretization.

[0047] The position tolerance can define a shape such as a circular disk, a line segment, a rectangle or an ellipse that lies in the plane around the reference point target position and specifies permissible positions for the reference point and thus permissible measuring positions for the measuring sensor.

[0048] Preferably, the target measuring direction, the measuring direction of the measuring sensor or the optimal measuring direction is in the plane.

[0049] A normal to the plane can, for example, correspond to a tangent to a spline that passes through the plurality of measurement points and defines the measurement path. This refers, in particular, to the tangent at the respective measurement point (i.e., the normal to the plane points in a direction along the measurement path).

[0050] Alternatively, the normal of the plane can enclose an angle with the tangent to the spline, where the angle corresponds to the intersection angle between the nominal measuring direction and the optimal measuring direction of the measuring sensor. Alternatively, the angle corresponds to the intersection angle between the nominal measuring direction and the measuring direction of the measuring sensor.

[0051] According to yet another embodiment, in step (ii) for each of the plurality of measuring points, permissible axis positions are additionally determined for at least one other of the plurality of movement axes, and the determination of the optimal axis position of the at least one movement axis carried out in step (iii) is dependent on the permissible axis positions of the at least one other movement axis determined in step (ii).

[0052] This has the advantage that the optimization of the movement of the measuring sensor takes into account the kinematics of at least one other of the plurality of movement axes or the kinematic relationship of the plurality of movement axes to one another.

[0053] According to a further embodiment, the plurality of movement axes include a plurality of rotational axes, wherein in step (i) the plurality of permissible measuring directions of the measuring sensor are determined for each of the plurality of measuring points based on the desired measuring direction for the respective measuring point, in step (ii) the plurality of permissible axis positions of at least one rotational axis are determined for each of the plurality of measuring points based on the permissible measuring directions, and in step (iii) the optimal axis position of the at least one rotational axis is determined for each of the plurality of measuring points from the plurality of permissible axis positions of the at least one rotational axis previously determined for the respective measuring point.

[0054] This design therefore particularly takes into account the utilization of the orientation tolerance of the measuring sensor. This is particularly advantageous when the rotational movement of the measuring sensor along the multiple rotational axes significantly influences the measurement process when measuring the target.

[0055] Preferably, the optimal axis position is determined for each of the plurality of rotation axes (dependently or independently of each other).

[0056] According to a further embodiment, the plurality of movement axes comprise a plurality of linear axes, wherein in step (i) the plurality of permissible measuring positions of the measuring sensor for each of the plurality of measuring points are determined based on a reference point target position for the respective measuring point, in step (ii) the plurality of permissible axis positions of at least one linear axis for each of the plurality of measuring points are determined based on the permissible measuring positions for the respective measuring point, and in step (iii) the optimal axis position of the at least one linear axis for each of the plurality of measuring points is determined from the plurality of permissible axis positions of the at least one linear axis previously determined for the respective measuring point.

[0057] This design therefore particularly takes into account the utilization of the position tolerance of the measuring sensor. This allows the movement of the measuring sensor along at least one linear axis to be optimized.

[0058] Preferably, the optimal axis position is determined for each of the plurality of linear axes (dependently or independently of each other).

[0059] According to a further embodiment, the plurality of movement axes include a plurality of linear axes and a plurality of rotational axes, wherein in step (i) the plurality of permissible measuring directions of the measuring sensor for each of the plurality of measuring points are determined based on the desired measuring direction for the respective measuring point, in step (ii) the plurality of permissible axis positions of at least one rotational axis for each of the plurality of measuring points are determined based on the permissible measuring directions, in step (iii) the optimal axis position of the at least one rotational axis for each of the plurality of measuring points is determined from the plurality of permissible axis positions of the at least one rotational axis previously determined for the respective measuring point, in a step (iv) the plurality of permissible measuring positions of the measuring sensor for each of the plurality of measuring points are determined based on a reference point desired position for the respective measuring point,in a step (v), the plurality of permissible axis positions of at least one linear axis for each of the plurality of measuring points are determined based on the permissible measuring positions for the respective measuring point, and in a step (vi) the optimal axis position of the at least one linear axis for each of the plurality of measuring points is determined from the plurality of permissible axis positions of the at least one linear axis previously determined for the respective measuring point.

[0060] This design therefore takes into account both the orientation tolerance and the position tolerance of the measuring sensor. This allows the movement of the measuring sensor to be optimized both along the at least one rotational axis and along the at least one linear axis.

[0061] Preferably, the optimal axis position is determined for each of the plurality of rotary axes and for each of the plurality of linear axes (dependently or independently of each other).

[0062] Further preferably, the aforementioned steps (iv), (v) and (vi) are carried out while maintaining the optimal axis position of the at least one axis of rotation, which was previously determined in step (iii).

[0063] Thus, the optimal axis position of the at least one rotary axis is first determined, which specifies the optimal measuring direction of the measuring sensor, and then the optimal axis position of the at least one linear axis is determined, which defines the optimal measuring position of the measuring sensor. This has the advantage that the measuring position of the measuring sensor can be varied while maintaining the optimal measuring direction, without significantly compromising the measuring accuracy.

[0064] In the present case, the optimal measuring position refers to a measuring position of the measuring sensor which is determined by the optimal axis position of the at least one linear axis determined in step (iii).

[0065] According to a further embodiment, the optimization of the movement of the measuring sensor in step (iii) comprises a temporal optimization and / or an optimization of changes in the magnitude of the axis position of the at least one movement axis.

[0066] In particular, the movement of the measuring sensor can be optimized along the movement axes that are crucial for the measurement sequence or the measurement duration. For example, this can make the movement along the numerous movement axes less jerky. Furthermore, "reversals" of the movement axes can be avoided. In this case, a reversal refers to a relatively large change in a movement axis that is accompanied by only a relatively small change in the measuring position of the measuring sensor or the measuring direction of the measuring sensor. The temporal optimization can be carried out taking into account limit values ​​for permissible speeds and / or accelerations of the measuring sensor.

[0067] It is understood that the type of optimization, ie the optimization directed towards time and / or the amount of change in the axis position, can change in sections along the measurement path (for example, by specification by the user of the measuring device).

[0068] According to a further embodiment, the optimization of the change in the amount of the axis position of the at least one movement axis takes place under a condition that the at least one movement axis is moved as minimally as possible from one of the measuring points to a subsequent one of the plurality of measuring points, or that an overall movement of the at least one movement axis along the plurality of measuring points is as minimal as possible.

[0069] Advantageously, the measurement of the measuring object can be carried out in such a way that at least one axis of movement is moved as little as possible and thus the measuring sensor is also moved as little as possible.

[0070] Preferably, the change in magnitude of one or more axes of rotation is minimized.

[0071] According to a further embodiment, the temporal optimization is carried out under a condition that the time required to move the measuring sensor along the at least one movement axis from one of the measuring points to a subsequent one of the plurality of measuring points is as short as possible, or that a total duration required to move the measuring sensor along the at least one movement axis and along the plurality of measuring points is as short as possible.

[0072] This has the advantage that the measurement of the measuring object can be carried out as quickly as possible.

[0073] According to a further embodiment, the method comprises the steps of: determining control data based on the optimal axis position of the at least one movement axis for each of the plurality of measuring points and moving the measuring sensor based on the control data.

[0074] Advantageously, the optimal axis position of the at least one movement axis for each of the plurality of measuring points can be quickly and easily converted into control data for the movement axes of the measuring device. Furthermore, the measuring sensor can advantageously be moved according to the optimal axis position of the at least one movement axis previously determined in step (iii).

[0075] It is understood that the method claims also apply mutatis mutandis to the claims directed to the measuring device.

[0076] As already mentioned at the beginning, a further aspect of the present invention relates to a measuring device for determining dimensional and / or geometric properties of a measuring object, comprising: - a measuring object recording, - a measuring sensor which defines a reference point for measuring the measuring object and is movable within a measuring volume relative to the measuring object holder along a plurality of movement axes for measuring a plurality of measuring points of the measuring object, - a controller configured to move the measuring sensor along the plurality of movement axes in dependence on control data, and - a processor configured to determine the control data for the controller, wherein the processor is configured to determine control data: (i) to determine a plurality of permissible measuring directions of the measuring sensor for each of the plurality of measuring points based on a target measuring direction for the respective measuring point, wherein the plurality of permissible measuring directions maintain a measuring direction tolerance with respect to the target measuring direction for the respective measuring point, and / or to determine a plurality of permissible measuring positions of the measuring sensor for each of the plurality of measuring points based on a reference point target position for the reference point for the respective measuring point, wherein in the plurality of permissible measuring positions of the measuring sensor, the reference point maintains a position tolerance with respect to the reference point target position, (ii) to determine a plurality of permissible axis positions of at least one movement axis of the plurality of movement axes for each of the plurality of measuring points based on the permissible measuring directions and / or permissible measuring positions for the respective measuring point, and (iii) to determine an optimal axis position of the at least one movement axis for each of the plurality of measuring points from the plurality of permissible axis positions previously determined for the respective measuring point in order to optimize the movement of the measuring sensor in the measuring volume.

[0077] Advantageously, it is not necessary to align the measuring sensor precisely according to the target measuring direction and / or the reference point target position for each measuring point. Instead, the optimal axis position of at least one movement axes is determined while maintaining the measuring direction tolerance and / or the position tolerance. This allows the movement of the measuring sensor to be improved without significantly compromising the measurement accuracy, while simultaneously fulfilling a measuring task with the required measurement accuracy.

[0078] According to one embodiment, the measuring device comprises: - an interface for receiving parameters that define, for each of the plurality of measuring points, the target measuring direction, the reference point target position, the measuring direction tolerance, and / or the measuring position tolerance and / or define limit values ​​for permissible speeds and / or accelerations of the measuring sensor along the plurality of movement axes, and - a memory in which the parameters can be stored.

[0079] Advantageously, the parameters can be stored in the memory and the processor can use the data in determining the control data.

[0080] The interface could be, for example, a user interface through which parameters can be entered. Alternatively, the interface could receive parameters from another (technical) device.

[0081] The above-mentioned aspects of the method also apply equivalently to the measuring device:

[0082] In particular, according to another embodiment, the target measuring direction and the plurality of permissible measuring directions for the respective measuring point pass through a common point.

[0083] According to a further embodiment, the permissible measuring directions for the respective measuring point lie within a defined enveloping cone around the target measuring direction.

[0084] According to yet another embodiment, in the case of the plurality of permissible measuring positions of the measuring sensor, the reference point lies in a plane with the respective reference point target position.

[0085] According to another embodiment, the processor is configured to determine, in (ii), for each of the plurality of measuring points, additionally step-permissible axis positions for at least one other of the plurality of movement axes, wherein the determination of the optimal axis position of the at least one movement axis carried out in (iii) is step-dependent on the permissible axis positions of the at least one other movement axis determined in (ii).

[0086] According to a further embodiment, the plurality of movement axes include a plurality of rotation axes and the processor is configured to (i) determine the plurality of permissible measuring directions of the measuring sensor for each of the plurality of measuring points based on the desired measuring direction for the respective measuring point, (ii) determine the plurality of permissible axis positions of at least one rotation axis for each of the plurality of measuring points based on the permissible measuring directions and (iii) determine the optimal axis position of the at least one rotation axis for each of the plurality of measuring points from the plurality of permissible axis positions of the at least one rotation axis previously determined for the respective measuring point.

[0087] According to yet another embodiment, the plurality of movement axes comprise a plurality of linear axes, and the processor is configured to (i) determine the plurality of permissible measuring positions of the measuring sensor for each of the plurality of measuring points based on a reference point target position for the respective measuring point, (ii) determine the plurality of permissible axis positions of at least one linear axis for each of the plurality of measuring points based on the permissible measuring positions for the respective measuring point, and (iii) determine the optimal axis position of the at least one linear axis for each of the plurality of measuring points from the plurality of permissible axis positions of the at least one linear axis previously determined for the respective measuring point.

[0088] According to another embodiment, the plurality of movement axes include a plurality of linear axes and a plurality of rotational axes, and the processor is configured to (i) determine the plurality of permissible measuring directions of the measuring sensor for each of the plurality of measuring points based on the desired measuring direction for the respective measuring point, (ii) determine the plurality of permissible axis positions of at least one rotational axis for each of the plurality of measuring points based on the permissible measuring directions, (iii) determine the optimal axis position of the at least one rotational axis for each of the plurality of measuring points from the plurality of permissible axis positions of the at least one rotational axis previously determined for the respective measuring point, (iv) determine the plurality of permissible measuring positions of the measuring sensor for each of the plurality of measuring points based on a reference point desired position for the respective measuring point,in (v) to determine the plurality of permissible axis positions of at least one linear axis for each of the plurality of measuring points based on the permissible measuring positions for the respective measuring point, and in (vi) to determine the optimal axis position of the at least one linear axis for each of the plurality of measuring points from the plurality of permissible axis positions of the at least one linear axis previously determined for the respective measuring point.

[0089] According to a further embodiment, the optimization of the movement of the measuring sensor comprises a temporal optimization and / or an optimization of changes in the magnitude of the axis position of the at least one movement axis.

[0090] According to yet another embodiment, the optimization of the change in the amount of the axis position of the at least one movement axis takes place under a condition that the at least one movement axis is moved as minimally as possible from one of the measuring points to a subsequent one of the plurality of measuring points, or that an overall movement of the at least one movement axis along the plurality of measuring points is as minimal as possible.

[0091] According to another embodiment, the temporal optimization is carried out under a condition that the time required to move the measuring sensor along the at least one movement axis from one of the measuring points to a subsequent one of the plurality of measuring points is as short as possible, or that a total duration required to move the measuring sensor along the at least one movement axis along the plurality of measuring points is as short as possible.

[0092] As already mentioned at the outset, a further aspect of the present invention relates to a computer program product with program code which is configured to carry out the method when the program code is executed on the processor of the measuring device.

[0093] It is understood that the features mentioned above and those explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0094] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. They show: Fig. 1 shows a simplified, schematic representation of a measuring device according to an embodiment of the present invention; Fig. 2 a simplified, schematic representation of rotation axes; Fig. 3 a schematic representation of a measuring sensor; Fig. 4 a schematic representation of a dynamic range of the measuring sensor; Fig. 5 a schematic representation of a tilting of the measuring sensor; Fig. 6 is a schematic representation of a method according to an embodiment of the present invention; Fig. 7 a schematic representation of a measurement direction tolerance; Fig. 8 a schematic representation of a position tolerance; Fig. 9 a schematic representation of a selection of the optimal axis position; Fig. 10 a schematic representation of a variety of optimal measuring directions; Fig. 11 a schematic representation of a variety of optimal measuring positions; and Fig. 12a schematic representation of a variety of optimal measuring positions taking into account the optimal measuring direction.

[0095] Fig. 1 to 3 show a simplified representation of a measuring device in which the present invention can be used. The measuring device is designated in its entirety by the reference numeral 10 and, in this example, is embodied as a coordinate measuring machine. The coordinate measuring machine 10 has a gantry design. It is understood, however, that this is merely one of various possible designs of a coordinate measuring machine, based on which the basic structure and function of a coordinate measuring machine will be explained below. However, the present invention is by no means limited to the control of such a designed coordinate measuring machine, but can also be used to control other measuring devices used in dimensional metrology.

[0096] The coordinate measuring machine 10 has a measuring sensor 12 for measuring a workpiece and a workpiece holder 14 on which the workpiece, a measuring object 16, can be placed.

[0097] In this case, a gantry 18 is arranged on the workpiece holder 14, which is also referred to as the base. The gantry 18 serves as a movable support structure for the measuring sensor 12 and has two columns 20 and a crossbeam 22, on which a carriage 24 is movably mounted. The carriage 24 carries a sleeve 26, to the lower end of which a change interface 28 is attached. A multi-axis rotary joint 30 is arranged on the change interface 28, which supports the measuring sensor 12. The multi-axis rotary joint 30 has three axes of rotation A, B, and C ( Fig. 2).

[0098] The measuring sensor 12 is configured as an optical measuring sensor with a laser element 32 and an image sensor element 34 ( Fig. 3).

[0099] The coordinate measuring machine 10 further comprises a positioning device 36 for positioning the measuring sensor 12 and the measuring object holder 14 relative to one another. This positioning device 36 includes a control unit 38, a plurality of drives by means of which the measuring sensor 12 and the measuring object holder 14 are moved relative to one another, and a plurality of measuring scales 42. The control unit 38 comprises a controller 44, a processor 46, a memory 48, and an operating terminal 50, which, for example, comprises a monitor 52 and a keyboard 54.

[0100] In the present example, in which the measuring device 10, the coordinate measuring machine, is implemented in a gantry design, the aforementioned drives move the measuring sensor 12 relative to the measurement object holder 14, which is fixed. The measuring sensor 12 can be moved along three orthogonally aligned coordinate axes. These coordinate axes are referred to herein as linear axes X, Y, Z. One of these drives is provided with the reference numeral 40, for example. This drive 40 is configured to move the gantry 16 along the y-axis relative to the measurement object holder 14. The carriage 24 can be moved along the linear axis X with the aid of a further drive (not separately designated here) on the crossbeam 22. The sleeve 26 can be moved relative to the carriage 24 along the linear axis Z.

[0101] The measuring scales 42, in conjunction with corresponding read heads (not shown here), are designed to determine the current position of the gantry 16 relative to the workpiece support 12, the relative position of the carriage 24 relative to the crossbeam 22, and the position of the sleeve 26 relative to the carriage 24. Encoders are arranged in the multi-axis rotary joint 30, with the aid of which a current rotational and pivoting position of the measuring sensor 30 relative to the sleeve 26 can be determined in a similar manner. The aforementioned position values ​​are fed to the control unit 38, which then determines the spatial coordinates of a measuring point on the measuring object 14 based on the scale and encoder values.

[0102] Furthermore, the control unit 38 is configured to control the drives for moving the gantry 16, the carriage 24 and the quill 26 as well as the drives of the multi-axis rotary joint 30 in order to bring the measuring sensor 12 into a defined position relative to the measuring object 14.

[0103] The control unit 38 generally serves not only to control the positioning device 36 and thus to control the individual drives, but also to evaluate the data obtained from the measuring sensor 12 and to determine the spatial coordinates of the measuring object 14 on the basis of the evaluated measurement data.

[0104] As in Fig. As shown schematically in Figure 2, the measuring sensor 12 can be rotated or pivoted relative to the measuring object 16 or the measuring object holder 14 by means of the three rotation axes A, B, and C. The rotation axes A and C run parallel to each other and are laterally offset from each other in the direction of the rotation axis B. The rotation axis B runs orthogonally to the rotation axes A and B and is arranged between the rotation axis A and the rotation axis B.

[0105] The determination of an orientation of the measuring object 16 relative to the measuring object holder 14 can be carried out by means of defined reference points of the measuring object 16.

[0106] Fig. Figure 3 shows a schematic representation of the measuring sensor 12, which is configured here as an optical triangulation laser sensor. The laser element 32 projects light onto the surface of the measuring object 16. For example, the laser element 32 is a laser diode. The image sensor element 34 detects the light reflected from the surface of the measuring object 16. Based on the properties of the detected light and trigonometric relationships, the distance of the surface of the measuring object 16 illuminated by the light from the measuring sensor 12 can be calculated. This allows conclusions to be drawn about the dimensional and / or geometric properties of the measuring object 16.

[0107] In a known procedure, the measurement is performed at a measuring point 56 based on a target measuring direction 58 and a reference point target position 60, which are specified for each of a plurality of measuring points 56. The target measuring direction 58 specifies a measuring direction 59 of the measuring sensor 12. The reference point target position 60 defines coordinates of the measuring point 56 in the Cartesian coordinate system x, y, z.

[0108] The target measuring direction 58 and the reference point target position 60 can, for example, be specified by the user via the operator terminal 50. Alternatively, the target measuring direction 58 and the reference point target position 60 can be specified by the controller 44. For example, the target measuring direction 58 and the reference point target position 60 can be derived from a CAD model of the measurement object 16.

[0109] The measuring sensor 12 defines a reference point 62, the so-called tool center point (TCP), which, when the measuring sensor 12 is precisely aligned, comes to lie in the specified reference point target position 60. For the measurement along the plurality of measuring points 56, the reference point 62 is moved according to a plurality of reference point target positions 60 on the surface of the measuring object 16.

[0110] With a precise alignment of the measuring sensor 12, the measuring direction 59 corresponds to the target measuring direction. The target measuring direction 58 determines the angle at which a defined reference axis of the measuring sensor 12 should be oriented to the surface of the measuring object 16. In this case, a laser element axis 64 defines the measuring direction 59 of the measuring sensor 12. The laser element axis 64 forms an angle β with the surface of the measuring object 16, which angle is specified for the measurement via the target measuring direction 58.

[0111] Alternatively, the target measuring direction 58 can also be specified via the image sensor element axis 66, which forms a fixed angle α with the laser element axis 64. In this case, the image sensor element axis 66 defines the measuring direction 59 of the measuring sensor 12.

[0112] The angle β can be, as in Fig. 3, 90°. For highly reflective surfaces of the measuring object 16, it may be advantageous to specify the angle β at a value other than 90°, for example, with β = 90° ± 10..15°.

[0113] The "tilting" of the target measuring direction 58 occurs in this case relative to a measuring path 68 (here also referred to as "scan path" or "movement path"), which is predetermined by a defined sequence of the plurality of measuring points 56. The target measuring direction 58 encloses the angle β with a direction along the measuring path 68. Depending on the value of the angle β, the measuring sensor 12 thus "leads" the respective measuring point 56 along the measuring path 68 "ahead" (indicated by the reference point target position 60 and the reference point 62) or "behind" (indicated by the reference point target position 60' and the reference point 62') ( Fig. 2).

[0114] The measuring principles of such optical measuring sensors 12 are already fundamentally known in the prior art.

[0115] As in Fig. As indicated in Figure 2, the measuring sensor 12 can, for example, project a light line 70 onto the surface of the measurement object 16, with the reference point 62 located at a center point of the light line 70. The light line 70 is preferably aligned orthogonally to the direction of the measurement path 68. Four consecutive positions of the light line 70 along the measurement path 68 are indicated by the reference numerals 70', 70, 70'', 70'''. Conclusions about the properties of the surface of the measurement object 16 can be drawn from the curvature of the (light) stripes.

[0116] Alternatively, the measuring sensor 12 can project other light patterns onto the surface of the measurement object 16, such as a light pattern with a plurality of parallel stripes. The underlying measuring principle is, for example, the well-known measuring principle of stripe projection, which is also referred to as stripe light scanning or stripe light topometry.

[0117] Regardless of the type of measuring principle of the measuring sensor 12, the present invention is based on the finding that an exact alignment of the measuring sensor 12 relative to the respective measuring point according to the target measuring direction 58 and the reference point target position 60 can be accompanied by relatively large changes in the axis positions of the linear X, Y, Z and / or the rotary axes A, B, C. However, the changes in the axis positions of the linear axes X, Y, Z and / or the rotary axes A, B, C are usually time-consuming, which has a negative impact on the measuring time required for measuring along the multitude of measuring points 56 along the measuring path 68.

[0118] The idea underlying the invention is in Fig. 4 and Fig. 5 illustrates this schematically. Fig. 4 shows a view in the direction of the measuring path 68 ( Fig. 2) and a schematic representation of a tolerance range 72 of the measuring sensor 12, which is also referred to herein as the dynamic range. A sufficiently appropriate measurement accuracy can be achieved within the tolerance range 72. According to the invention, the tolerance range 72 is utilized to optimize the movement of the measuring sensor 12 without significantly impairing the measurement accuracy.

[0119] When utilizing the tolerance range 72, the reference point 62 can be shifted in the tolerance range 72 relative to the reference point target position 60 (in Fig. 4 not shown). The utilization of a width b of the tolerance range 72 can be limited by a length I of the light line 70.

[0120] In addition, the measuring direction 59 of the measuring sensor 12 can be tilted relative to the nominal measuring direction 58 by a tolerance angle γ ( Fig. 5). Tolerance range 72 is "tilted" along with the change. Alternatively, tolerance range 72 is not tilted.

[0121] Fig. 5 shows a measuring sensor 12 tilted clockwise by the tolerance angle γ (relative to the Fig. 4). It is understood that the measuring sensor 12 can also be tilted counterclockwise.

[0122] The tolerance angle may depend on various factors such as properties of, for example, the surface of the measuring object 16 (including reflection properties), the measuring sensor 12, the measuring task, a required measuring accuracy and / or possible collisions with the measuring object 16 and / or clamping devices of the measuring device 10.

[0123] An optimal angle range can be determined, for example, by evaluating the scatter in a series of measurements with different angular positions on the surface of the measuring object 16.

[0124] For example, the tolerance angle γ parallel to the light line 70 with the measuring range m and a length l of the light line 70 can be determined using the relationship γ = tan -1 (m / l). For a measuring range m = 60 mm and a length l = 80 mm of the light line 70, this results in an angle γ of approximately 37°.

[0125] A tolerance angle perpendicular to the light line 70 can correspond to the tolerance angle γ parallel to the light line 70. By constructing an optical line triangulation sensor 12, a maximum orientation tolerance of < 180° - α is possible in principle. In certain applications, an orientation deviation of ± 180° may be possible in partial areas, whereby directional specifications for these areas are no longer observed.

[0126] Fig. 6 to 9 show a schematic representation of a first exemplary embodiment of a method 74 for controlling the measuring device 10. In a first step (i), a plurality of permissible measuring directions 76 of the measuring sensor 12 are determined for each of the plurality of measuring points 56 based on a desired measuring direction 58 for the respective measuring point 56, wherein the plurality of permissible measuring directions 76 maintain a measuring direction tolerance with respect to the desired measuring direction 58, and / or a plurality of permissible measuring positions 84 of the measuring sensor 12 are determined for each of the plurality of measuring points 65 based on a reference point desired position 60 for the respective measuring point 56, wherein the reference point 62 maintains a position tolerance with respect to the reference point desired position 60.

[0127] In a second step (ii), a plurality of permissible axis positions 86 of at least one movement axis X, Y, Z, A, B, C of the plurality of movement axes X, Y, Z, A, B, C are determined for each of the plurality of measuring points 56 based on the permissible measuring directions 76 and / or the permissible measuring positions 84 for the respective measuring point 56.

[0128] In a third step (iii), an optimal axis position 94 of the at least one movement axis X, Y, Z, A, B or C is determined for each of the plurality of measuring points 56 from the plurality of permissible axis positions 86 previously determined for the respective measuring point 56 in order to optimize the movement of the measuring sensor 12 in the measuring volume.

[0129] Based on the optimal axis position 94 of the at least one movement axis X, Y, Z, A, B, C, the processor 46 determines control data that are used by the controller 44 to move the measuring sensor 12 along the movement axes X, Y, Z, A, B, C.

[0130] The optimization of the axis position of at least one movement axis X, Y, Z, A, B, C is carried out taking into account limit values ​​for permissible speeds and / or accelerations of the measuring sensor 12 along the respective movement axis X, Y, Z, A, B, C. The limit values ​​for the permissible speeds and / or accelerations are stored in the memory 48 ( Fig. 1).

[0131] The memory 48 also stores the target measuring direction 58, the reference point target position 60, the measuring direction tolerance and the measuring position tolerance for each of the plurality of measuring points 56.

[0132] Fig. Figure 7 shows a schematic representation of the multitude of permissible measuring directions, some of which are provided with the reference numeral 76 for illustrative purposes. The permissible measuring directions 76 run with the nominal measuring direction 58 through a common point, which in this case corresponds to the reference point 62 or the reference point nominal position 60. The permissible measuring directions 76 lie within an enveloping cone 78, which specifies a maximum intersection angle between the nominal measuring direction 60 and one of the multitude of permissible measuring directions 76, which corresponds to the tolerance angle γ.

[0133] For example, the tolerance angle, which is defined here by the envelope cone 78 and corresponds to half the opening angle of the envelope cone 78, is approximately 35°.

[0134] The permissible measuring directions 76 can be determined equally for optical and tactile measuring sensors 12.

[0135] The permissible measurement directions 76 are discretized within the enveloping cone 78, which is indicated by a grid on the enveloping cone 78. The finer the resolution, the more precise, but also the more computationally intensive, the optimization of the axis position of at least one movement axis X, Y, Z, A, B, C. The degree of discretization can be determined as needed for the application.

[0136] Alternatively, the plurality of permissible measurement directions 76 can be limited by any other arbitrary envelope shape, such as a pyramid. The shape of the envelope can be defined independently of each other in the direction and perpendicular to the measurement path 68.

[0137] Fig. 8 shows a schematic representation of the position tolerance along the measuring path 68. The measuring path 68 is defined by a spline that runs through the plurality of measuring points 56 or the corresponding reference point target positions 60. For each measuring point 56, permissible positions of the reference point 62 lie in a circular plane E around the measuring point 56 or the corresponding target position 60. By way of example, a few permissible positions of the reference point are identified by the reference symbol 80. A normal n of the plane E corresponds to a tangent of the spline at the respective measuring point 56 or the respective reference point target position 60. A boundary of the plane E in space defines maximum deviations of the reference point 62 from the reference point target position 60 in the plane E. In the direction of the normal n of the plane E, the position tolerance is essentially zero.

[0138] In this example, the plurality of permissible positions 80 of the reference point 62 form a tubular tolerance range 82 along the measuring path 68. The diameter of the plane E at the respective measuring point 56 or the respective reference point target position 60 is, for example, up to one centimeter.

[0139] Alternatively, the tolerance range 82 may also have any two-dimensional shape, such as an elliptical, rectangular or square cross-section, or be defined by a straight line or a line.

[0140] The plurality of permissible positions 80 of the reference point 62 for the respective measuring point 56 are converted into the plurality of permissible measuring positions of the measuring sensor 12, which are schematically illustrated here for one of the plurality of measuring points 56 and designated by reference numeral 84. Due to the fixed geometric relationship between the reference point 62 and the measuring sensor 12, the plurality of permissible measuring positions 84 of the measuring sensor 12 varies with the same position tolerance as the permissible positions 80 of the reference point 62.

[0141] Alternatively, the reference point 62 is arranged within the measuring sensor 12 (for example in the case of a tactile measuring sensor), so that the permissible positions 80 of the reference point 62 can correspond to the permissible measuring positions 84 of the measuring sensor 12.

[0142] From the optimal axis position of one or more linear axes X, Y, Z, the optimal measuring path 68' is then determined, along which the position tolerance for the respective measuring point 56 is maintained.

[0143] Fig. 9 shows a schematic representation of the selection of the optimal axis position of the at least one movement axis X, Y, Z, A, B, C from the multitude of permissible axis positions of the at least one movement axis X, Y, Z, A, B, C, which are indicated here by way of example with the reference numeral 86. The permissible axis positions 86 are located around a conventional, non-optimized axis position 88 (corresponding to an exact alignment of the measuring sensor 12 with the desired measuring direction 58 and / or the reference point desired position 60). The permissible axis positions 86 are limited for each measuring point 56 by a maximum permissible axis position 90 and a minimum permissible axis position 92.

[0144] The optimal axis position 94 is determined such that the at least one movement axis X, Y, Z, A, B, C is moved as little as possible without exceeding the measuring direction tolerance and / or the position tolerance.

[0145] Alternatively, the time required to move the measuring sensor along one or more axes of motion along the measurement path can be minimized.

[0146] In this case, the optimal axis position is determined using a "Euclidean Shortest Path" search algorithm. It is understood that another suitable algorithm for determining the optimal axis position of at least one movement axis can be used.

[0147] The optimal axis position 94 at the respective measuring point 56 depends on the plurality of permissible axis positions 86 of the at least one movement axis X, Y, Z, A, B, C for the subsequent or previous measuring points 56, so that the optimization of the axis position takes place with respect to the entire measuring path 68.

[0148] The optimization of the axis position can be carried out dependently or independently of the other motion axes X, Y, Z, A, B, C. If several motion axes X, Y, Z, A, B, C, such as the three rotation axes A, B, C, are optimized simultaneously, the permissible axis positions 86 of the rotation axes A, B, C at the respective measuring point 56 and along the measuring path 68 form a three-dimensional shape within which the optimal axis position 94 for each of the rotation axes A, B, C can be determined.

[0149] Fig. 10 shows a schematic representation of the optimization of the measuring direction 59 of the measuring sensor 12 with a depression 96 of the measuring object 16. The proportions are in Fig. 10 exaggerated for clarity. In Fig. 10, the target measuring direction 58, the plurality of permissible measuring directions 76 and an optimal measuring direction 98 are indicated by way of example at the plurality of measuring points 56.

[0150] The optimal measuring direction 98 is determined by the optimal axis position 94 of one or more of the rotation axes A, B, C and corresponds to the measuring direction 59 of the measuring sensor 12 with the optimal axis position 94 of one or more of the rotation axes A, B, C.

[0151] Since the optimal axis position 94 and thus the optimal measuring direction 98 is used in the recess 96, the measuring direction 59 can be maintained along the multitude of measuring points in this example. Thus, the rotational axis A, B, and / or C is changed as little as possible.

[0152] Fig. 11 shows the same recess 96 as in Fig. 10 schematically illustrates the optimization of the position of the reference point 62 or the measuring position of the measuring sensor 12. The recess 96 has, for example, a depth of t = 20 mm. The permissible positions 80 of the reference point 62 for the respective measuring point 56 lie in the respective plane E. The normal n of the plane E is oriented perpendicular to the measuring path 68, which runs through the plurality of measuring points 56.

[0153] The optimal measuring position of the measuring sensor 12 (not shown here) is determined such that the axis position of one or more of the plurality of linear axes X, Y, Z is changed as little as possible in order to move the measuring sensor 12 along the measuring path 68. The corresponding optimal position of the reference point 62 is designated by reference numeral 100. The optimal measuring path 68' runs through the respective optimal position 100 of the reference point 62 of the plurality of measuring points 56.

[0154] Fig. 12 shows a schematic representation of the optimization of the position of the reference point 62 or the measuring position of the measuring sensor 12 at the same depression 96 of the measuring object 16 as in Fig. 10 and Fig. 11. In contrast to the Fig. In the example shown in Figure 11, the optimization of the measuring position of the measuring sensor 12 takes place taking into account the optimal measuring direction 98, which was previously determined according to step (iii) of the method 74 ( Fig. 10). This corresponds to an optimization of the axis position of at least one rotary axis A, B, C and a subsequent optimization of the axis position of at least one linear axis X, Y, Z.

[0155] In contrast to Fig. 11, in the depression 96 of the measuring object 16, the measuring direction 59 of the measuring sensor 12, which corresponds to an optimal measuring direction 98, deviates from the nominal measuring direction 58. The plane E, which describes the position tolerance, contains the optimal measuring direction 98. Thus, in comparison to the Fig. In the example shown in Figure 11, the plane E is tilted at the corresponding measuring points 56 in the recess 96.

[0156] The optimal axis position 94 of the one or more rotary axes A, B, C thus influences permissible measuring positions 84 of the measuring sensor 12 and thus also the optimal axis position 94 of the one or more linear axes X, Y, Z.

[0157] The measuring sensor 12 can then be moved along the measuring path 68 or 68' according to an optimal measuring direction 98 and an optimal measuring position of the measuring sensor 12, wherein the optimal measuring direction 98 is predetermined by the optimal axis position 94 of one or more rotary axes A, B, C and the optimal measuring position of the measuring sensor 12 is predetermined by the optimal axis position 94 of one or more linear axes X, Y, Z.

[0158] It is understood that the exemplary embodiments shown in the figures merely show exemplary embodiments of the method according to the invention for controlling the coordinate measuring machine and of the coordinate measuring machine according to the invention, which are intended to illustrate the advantages of the method according to the invention and of the coordinate measuring machine according to the invention.

[0159] Various modifications can be made to these embodiments without departing from the scope of the present invention. For example, the measuring sensor, which is configured here as an optical measuring sensor, can also be configured as a tactile measuring sensor.

[0160] It should be noted that the present invention is explained merely by way of example using a gantry-type coordinate measuring machine. In principle, however, the invention can also be used, for example, with cantilever, bridge, or column-type measuring devices. Depending on the design of the measuring device, the relative movement of the measuring object holder and the measuring sensor along one, two, or all three spatial directions x, y, z can also be realized by movability of the measuring object holder.

[0161] Likewise, the measuring device can have any number of linear and / or rotary axes.

[0162] As an example, a positioning device was described that allows the measuring sensor to be positioned relative to the measuring object. Additionally or alternatively, the measuring object can be arranged on a rotary table that can be moved and positioned relative to the measuring sensor.

[0163] In the illustrated embodiment, the measurement position tolerances were specified relative to the reference point. It is understood that, due to the fixed geometric relationship between the reference point and the measuring sensor, the measurement position tolerance applies equivalently to the position of the measuring sensor. The measurement position tolerance can therefore also be specified for the measuring sensor itself.

[0164] Furthermore, the permissible positions of the reference point for the respective measurement point can generally be in a three-dimensional shape, such as a circular disk with a specified thickness. The thickness of the three-dimensional shape (in the direction of the measurement path) can be specified depending on the distance between the measurement points. This can prevent overlaps between the permissible positions of the reference point of neighboring measurement points (along the measurement path). QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 110 508 A1 [0003, 0011]

Claims

[1] Method (74) for controlling a measuring device (10) for determining dimensional and / or geometric properties of a measurement object (16), wherein the measuring device (10) has a measurement object holder (14) and a measuring sensor (12), wherein the measuring sensor (12) defines a reference point (62) for measuring the measurement object (16) and is movable within a measurement volume relative to the measurement object holder (14) along a plurality of movement axes (X, Y, Z, A, B, C) for measuring a plurality of measuring points (56) of the measurement object (16), comprising the steps: (i) determining a plurality of permissible measuring directions (76) of the measuring sensor (12) for each of the plurality of measuring points (56) based on a desired measuring direction (58) for the respective measuring point (56), wherein the plurality of permissible measuring directions (76) maintain a measuring direction tolerance with respect to the desired measuring direction (58), and / or determining a plurality of permissible measuring positions (84) of the measuring sensor (12) for each of the plurality of measuring points (56) based on a reference point desired position (60) for the respective measuring point (56), wherein in the plurality of permissible measuring positions (84) of the measuring sensor (12), the reference point (62) maintains a position tolerance with respect to the reference point desired position (60), (ii) determining a plurality of permissible axis positions (86) of at least one movement axis (X, Y, Z, A, B, C) of the plurality of movement axes (X, Y, Z, A, B, C) for each of the plurality of measuring points (56) based on the permissible measuring directions (76) and / or the permissible measuring positions (84) for the respective measuring point (56), and (iii) determining an optimal axis position (94) of the at least one movement axis (X, Y, Z, A, B, C) for each of the plurality of measuring points (56) from the plurality of permissible axis positions (86) previously determined for the respective measuring point (56) in order to optimize the movement of the measuring sensor (12) in the measuring volume. [2] Method (74) according to claim 1, wherein for the respective measuring point (56) the desired measuring direction (58) and the plurality of permissible measuring directions (76) pass through a common point. [3] Method (74) according to claim 1 or 2, wherein for the respective measuring point (56) the permissible measuring directions (76) lie within a defined enveloping cone (78) around the desired measuring direction (58). [4] Method (74) according to one of the preceding claims, wherein in the plurality of permissible measuring positions (84) of the measuring sensor (12) the reference point (62) lies in a plane E with the respective reference point target position (60). [5] Method (74) according to one of the preceding claims, wherein in step (ii) for each of the plurality of measuring points (56) permissible axis positions (86) are additionally determined for at least one other of the plurality of movement axes (X, Y, Z, A, B, C), and the determination of the optimal axis position (94) of the at least one movement axis (X, Y, Z, A, B, C) carried out in step (iii) is dependent on the permissible axis positions (86) of the at least one other movement axis (X, Y, Z, A, B, C) determined in step (ii). [6] Method (74) according to one of the preceding claims, wherein the plurality of movement axes (X, Y, Z, A, B, C) include a plurality of rotational axes (A, B, C), wherein in step (i) the plurality of permissible measuring directions of the measuring sensor are determined for each of the plurality of measuring points (56) based on the desired measuring direction (58) for the respective measuring point (56), in step (ii) the plurality of permissible axis positions (86) of at least one rotational axis (A, B, C) are determined for each of the plurality of measuring points (56) based on the permissible measuring directions, and in step (iii) the optimal axis position (94) of the at least one rotational axis (A, B, C) is determined for each of the plurality of measuring points (56) from the plurality of permissible axis positions (86) of the at least one rotational axis (A, B, C) previously determined for the respective measuring point (56). [7] Method (74) according to one of claims 1 to 5, wherein the plurality of movement axes (X, Y, Z, A, B, C) include a plurality of linear axes (X, Y, Z), wherein in step (i) the plurality of permissible measuring positions (84) of the measuring sensor (12) for each of the plurality of measuring points (56) are determined based on a target position (60) for the respective measuring point (56), in step (ii) the plurality of permissible axis positions (86) of at least one linear axis (X, Y, Z) for each of the plurality of measuring points (56) are determined based on the permissible measuring positions (84) for the respective measuring point (56), and in step (iii) the optimal axis position (94) of the at least one linear axis (X, Y, Z) for each of the plurality of measuring points (56) is determined from the plurality of permissible axis positions (86) of the at least one linear axis previously determined for the respective measuring point (56). (X, Y, Z) is determined. [8] Method (74) according to one of claims 1 to 5, wherein the plurality of movement axes (X, Y, Z, A, B, C) include a plurality of linear axes (X, Y, Z) and a plurality of rotational axes (A, B, C), wherein in step (i) the plurality of permissible measuring directions of the measuring sensor are determined for each of the plurality of measuring points (56) based on the desired measuring direction (58) for the respective measuring point (56), in step (ii) the plurality of permissible axis positions (86) of at least one rotational axis (A, B, C) are determined for each of the plurality of measuring points (56) based on the permissible measuring directions, in step (iii) the optimal axis position (94) of the at least one rotational axis (A, B, C) for each of the plurality of measuring points (56) is determined from the plurality of permissible axis positions (86) of the at least one rotational axis (A, B, C) previously determined for the respective measuring point (56). is determined,in a step (iv), the plurality of permissible measuring positions (84) of the measuring sensor (12) for each of the plurality of measuring points (56) are determined based on a reference point target position (60) for the respective measuring point (56); in a step (v), the plurality of permissible axis positions (86) of at least one linear axis (X, Y, Z) for each of the plurality of measuring points (56) are determined based on the permissible measuring positions (84) for the respective measuring point (56); and in a step (vi), the optimal axis position (94) of the at least one linear axis (X, Y, Z) for each of the plurality of measuring points (56) is determined from the plurality of permissible axis positions (86) of the at least one linear axis (X, Y, Z) previously determined for the respective measuring point (56). [9] Method (74) according to one of the preceding claims, wherein the optimization of the movement of the measuring sensor (12) in step (iii) comprises a temporal optimization and / or an optimization of changes in the magnitude of the axis position of the at least one movement axis (X, Y, Z, A, B, C). [10] Method (74) according to claim 9, wherein the optimization of the change in the amount of the axis position of the at least one movement axis (X, Y, Z, A, B, C) takes place under a condition that the at least one movement axis (X, Y, Z, A, B, C) is moved as minimally as possible from one of the measuring points (56) to a subsequent one of the plurality of measuring points (56), or that an overall movement of the at least one movement axis (X, Y, Z, A, B, C) along the plurality of measuring points (56) is as minimal as possible. [11] Method (74) according to claim 9, wherein the temporal optimization takes place under a condition that the time required to move the measuring sensor (12) along the at least one movement axis (X, Y, Z, A, B, C) from one of the measuring points (56) to a subsequent one of the plurality of measuring points (56) is as small as possible, or that a total time required to move the measuring sensor (12) along the at least one movement axis (X, Y, Z, A, B, C) along the plurality of measuring points (56) is as small as possible. [12] Method (74) according to one of the preceding claims, comprising the following steps: - determining control data based on the optimal axis position (94) of the at least one movement axis (X, Y, Z, A, B, C) for each of the plurality of measuring points (56), and - Moving the measuring sensor (12) based on the control data. [13] Measuring device (10) for determining dimensional and / or geometric properties of a measuring object (16), comprising: - a measuring object holder (14), - a measuring sensor (12) which defines a reference point (62) for measuring the measurement object (16) and is movable within a measuring volume relative to the measurement object holder (14) along a plurality of movement axes (X, Y, Z, A, B, C) for measuring a plurality of measuring points (56) of the measurement object (16), - a controller (44) configured to move the measuring sensor (12) along the plurality of movement axes (X, Y, Z, A, B, C) in dependence on control data, and - a processor (46) configured to determine the control data for the controller, wherein the processor (46) is configured to determine control data: (i) to determine a plurality of permissible measuring directions of the measuring sensor (12) for each of the plurality of measuring points (56) based on a desired measuring direction (58) for the respective measuring point (56), wherein the plurality of permissible measuring directions maintain a measuring direction tolerance with respect to the desired measuring direction (58) for the respective measuring point (56), and / or to determine a plurality of permissible measuring positions (84) of the measuring sensor (12) for each of the plurality of measuring points (56) based on a reference point desired position (60) for the reference point (62) for the respective measuring point (56), wherein in the plurality of permissible measuring positions (84) of the measuring sensor (12), the reference point (62) maintains a position tolerance with respect to the reference point desired position (60), (ii) to determine a plurality of permissible axis positions (86) of at least one movement axis (X, Y, Z, A, B, C) of the plurality of movement axes (X, Y, Z, A, B, C) for each of the plurality of measuring points (56) based on the permissible measuring directions and / or permissible measuring positions (84) for the respective measuring point (56), and (iii) to determine an optimal axis position (94) of the at least one movement axis (X, Y, Z, A, B, C) for each of the plurality of measuring points (56) from the plurality of permissible axis positions (86) previously determined for the respective measuring point (56) in order to optimize the movement of the measuring sensor (12) in the measuring volume. [14] Measuring device (10) according to claim 13, comprising: - an interface (54) for receiving parameters which define, for each of the plurality of measuring points (56), the desired measuring direction (58), the reference point desired position (60), the measuring direction tolerance, and / or the measuring position tolerance and / or limit values ​​for permissible speeds and / or accelerations of the measuring sensor (12) along the plurality of movement axes (X, Y, Z, A, B, C), and - a memory (48) in which the parameters can be stored. [15] Computer program product with program code which is arranged to carry out the method (74) according to one of claims 1 to 12 when the program code is executed on the processor (46) of the measuring device (10) according to claim 13 or 14.

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