초록 ▼

A method for scanning a work piece surface uses a coordinate measurement device. A probe element is brought into contact with the surface and the probe element is moved along the surface. The coordinate measurement device has a plurality of degrees of freedom, which are independent of one another, i

A method for scanning a work piece surface uses a coordinate measurement device. A probe element is brought into contact with the surface and the probe element is moved along the surface. The coordinate measurement device has a plurality of degrees of freedom, which are independent of one another, in the possible movements of the probe element with respect to the work piece. Maximum speeds which describe the maximum of a movement speed component of the probe element based on the respective degree of freedom are defined for the degrees of freedom. An estimated path on which the probe element is intended to move during scanning is predefined. The actual scanning path can differ from the estimated scanning path. A maximum scanning speed at which the estimated scanning path can be traveled with a constant speed of the probe element is determined.

대표청구항 ▼

The invention claimed is: 1. A method for scanning a work piece surface with an aid of a coordinate measuring machine, which comprises the steps of: bringing a probe element of the coordinate measuring machine into contact with the work piece surface, and moving the probe element along the work pie

The invention claimed is: 1. A method for scanning a work piece surface with an aid of a coordinate measuring machine, which comprises the steps of: bringing a probe element of the coordinate measuring machine into contact with the work piece surface, and moving the probe element along the work piece surface while contact is maintained; providing the coordinate measuring machine with a plurality of mutually independent degrees of freedom of possible movements of the probe element with reference to a work piece, and defining for the degrees of freedom maximum speed magnitudes that describe a maximum of a movement speed component of the probe element referred to as a respective degree of freedom; prescribing for a planned scanning of the work piece an estimated scanning path on which the probe element is to move during scanning, and in which an actual scanning path can differ from the estimated scanning path in dependence on actual measurements of the work piece; and determining a maximum magnitude of a scanning speed at which the estimated scanning path can be traversed at a constant magnitude of a speed of the probe element by taking account of the maximum speed magnitudes for the degrees of freedom. 2. The method according to claim 1, wherein: at least one of the degrees of freedom is a degree of freedom of a linear axis of the coordinate measuring machine; account is taken when determining the maximum magnitude of the scanning speed of extreme points on the estimated scanning path that have a local maximum of a derivative of a magnitude of a coordinate with respect to the estimated scanning path; the coordinate is a spatial coordinate that is defined with reference to a coordinate axis that is a linear axis or that runs parallel to the linear axis; and the maximum magnitude of the scanning speed is fixed such that a magnitude of a speed component with reference to the coordinate axis does not exceed a maximum speed magnitude of the degree of freedom at any of the extreme points determined. 3. The method according to claim 2, which further comprises: taking into account the extreme points for all the degrees of freedom; forming, for each of the extreme points, a tangent vector that runs in a direction of a tangent at the extreme point; and using, in each case only a component of a tangent vector being an evaluation component, to calculate the maximum magnitude of the scanning speed, which is defined with reference to the degree of freedom, for which the extreme point was determined. 4. The method according to claim 3, which further comprises normalizing all the tangent vectors to an equal magnitude, and determining the maximum magnitude of the scanning speed from the evaluation components. 5. The method according to claim 4, which further comprises determining, from the evaluation components of the normalized tangent vectors and the maximum speed magnitudes for the respective degrees of freedom, which of the maximum speed magnitudes of the degrees of freedom limits the maximum magnitude of the scanning speed. 6. The method according to claim 5, wherein magnitudes of all of the evaluation components of a same degree of freedom are formed, the reciprocal values of the magnitudes are respectively multiplied by the maximum speed magnitude of the assigned degree of freedom and a minimum of a multiplication results is used to determine the maximum magnitude of the scanning speed. 7. The method according to claim 1, wherein at least a portion of the estimated scanning path has a round profile. 8. The method according to claim 7, which further comprises: defining for the round profile, a rectilinear axis that is a rotational symmetry axis of the round profile or is a projection of the round profile on to a plane perpendicular to a rotational symmetry axis; and taking into account the extreme points by forming a cross product of a vector in a direction of the rotational symmetry axis with a vector in a direction of a linear axis. 9. The method according to claim 7, which further comprises selecting the round profile from the group consisting of a circular arc, a helix, a spiral, an ellipse, and an oval. 10. A coordinate measuring machine, comprising: a probe element for scanning a work piece surface, said probe element being configured to be brought into contact with the work piece surface and to be moved while the contact along the work piece surface is maintained; a plurality of mutually independent degrees of freedom of possible movements of said probe element with reference to a work piece, and in which there are defined for the degrees of freedom maximum speed magnitudes that describe a maximum of a movement speed component of said probe element referred to a respective degree of freedom; and a speed determining device for evaluating a scanning path for a planned scanning of the work piece, in which said probe element is to move during scanning on the scanning path, in which an actual scanning path can differ from an estimated scanning path in dependence on actual measurements of the work piece, and said speed determining device is configured to determine, taking account of the maximum speed magnitudes for the various degrees of freedom, a maximum magnitude of the scanning speed at which the estimated scanning path can be traversed at a constant magnitude of the speed of said probe element. 11. The coordinated measuring machine according to claim 10, wherein said speed determining device is configured to execute a method for scanning a work piece surface, which comprises the steps of: bringing a probe element of the coordinate measuring machine into contact with the work piece surface, and moving the probe element along the work piece surface while contact is maintained; providing the coordinate measuring machine with a plurality of mutually independent degrees of freedom, of possible movements of the probe element with reference to a work piece, and defining for the degrees of freedom maximum speed magnitudes that describe a maximum of a movement speed component of the probe element referred to as a respective degree of freedom; prescribing for a planned scanning of the work piece an estimated scanning path on which the probe element is to move during scanning, and in which an actual scanning path can differ from the estimated scanning path in dependence on actual measurements of the work piece; determining a maximum magnitude of a scanning speed at which the estimated scanning path can be traversed at a constant magnitude of a speed of the probe element by taking account of the maximum speed magnitudes for the degrees of freedom; providing at least one of the degrees of freedom as a degree of freedom of a linear axis of the coordinate measuring machine; taking account when determining the maximum magnitude of the scanning speed of extreme points on the estimated scanning path that have a local maximum of a derivative of a magnitude of a coordinate with respect to the estimated scanning path; providing the coordinate as a spatial coordinate that is defined with reference to a coordinate axis that is a linear axis or that runs parallel to the linear axis; and fixing the maximum magnitude of the scanning speed such that a magnitude of a speed component with reference to the coordinate axis does not exceed a maximum speed magnitude of the degree of freedom at any of the extreme points determined. 12. The coordinated measuring machine according to claim 11, wherein said speed determining device is configured to: take into account the extreme points for all the degrees of freedom; form, for each of the extreme points, a tangent vector that runs in a direction of a tangent at the extreme point; and use, in each case only a component of a tangent vector being an evaluation component, to calculate the maximum magnitude of the scanning speed, which is defined with reference to the degree of freedom, for which the extreme point was determined. 13. The coordinated measuring machine according to claim 12, wherein said speed determining device is configured to normalize all the tangent vectors to an equal magnitude, and determine the maximum magnitude of the scanning speed from the evaluation components. 14. The coordinated measuring machine according to claim 13, wherein said speed determining device is configured to determine, from the evaluation components of the normalized tangent vectors and the maximum speed magnitudes for the respective degrees of freedom, which of the maximum speed magnitudes of the degrees of freedom limits the maximum magnitude of the scanning speed. 15. The coordinated measuring machine according to claim 14, wherein said speed determining device is configured to form magnitudes of all of the evaluation components of a same degree of freedom, respectively multiply the reciprocal values of the magnitudes by the maximum speed magnitude of the assigned degree of freedom and use a minimum of multiplication results to determine the maximum magnitude of the scanning speed. 16. The coordinated measuring machine according to claim 10, wherein said speed determining device is configured to execute a method for scanning a work piece surface, which comprises the steps of: bringing a probe element of the coordinate measuring machine into contact with the work piece surface, and moving the probe element along the work piece surface while contact is maintained; providing the coordinate measuring machine with a plurality of mutually independent degrees of freedom of possible movements of the probe element with reference to a work piece, and defining for the degrees of freedom maximum speed magnitudes that describe a maximum of a movement speed component of the probe element referred to as a respective degree of freedom; prescribing for a planned scanning of the work piece an estimated scanning path on which the probe element is to move during scanning, and in which an actual scanning path can differ from the estimated scanning path in dependence on actual measurements of the work piece; determining a maximum magnitude of a scanning speed at which the estimated scanning path can be traversed at a constant magnitude of a speed of the probe element by taking account of the maximum speed magnitudes for the degrees of freedom; and providing at least a portion of the estimated scanning path with a round profile. 17. The coordinated measuring machine according to claim 16, wherein said speed determining device is configured to: define for the round profile, a rectilinear axis that is a rotational symmetry axis of the round profile or is a projection of the round profile on to a plane perpendicular to a rotational symmetry axis; and take into account the extreme points by forming a cross product of a vector in a direction of the rotational symmetry axis with a vector in a direction of a linear axis. 18. The coordinated measuring machine according to claim 16, wherein said speed determining device is configured to select the round profile from the group consisting of a circular arc, a helix, a spiral, an ellipse, and an oval.