US 2004/0107063 A1 · Method for calibrating a measuring instrument

Abstract

The invention relates to a method and device for calibrating a measuring instrument with at least two partial systems (K;M), which can be displaced with regard to one another, and with means for generating an image of at least one first partial system (K) on at least one detecting component (A) of at least one partial system. The invention provides that after establishing a mathematical model, a parameter set, which quantifies influencing factors on systematic measurement errors of the measuring instrument and which has at least one parameter, is derived from the mathematical model. Afterwards, the imaging of the structure elements (S) of a first partial system (K), said structure elements determining the relative position of a partial system, ensues on a second partial system (M). The image of the structure elements (S) of the first partial system (K) is converted into signals by the detecting component (A), and at least one signal vector is recorded. Correction values, which reduce systematic measurement errors of the measuring instrument, are derived from the estimated values of the parameter set and made available.

Claims31

Dependent claims

Method for calibrating a measuring instrument

comprising at least two partial systems (K;
M) movable relative to one another and
comprising means (L) for producing an image of at least one first partial system (K)
on at least one detecting component (A) of at least one of the partial systems (K;
M),
comprising the following steps, it being possible for one or more of the following steps to be carried out several times,
formulation of a mathematical model describing the positions of the partial systems relative to one another and at least one image,
derivation of at least one parameter set which quantifies the factors influencing systematic measurement errors of the measuring instrument, with at least one parameter from the mathematical model,
generation of an image of structural elements (S) determining the relative position of a partial system and belonging to at least one first partial system (K)—preferably of a mark made on the first partial system (K)—on the second partial system (M) so that the image contains information about the relative position of the partial systems
conversion of the image of the structural elements of the first partial system into signals by the detecting component (A),
recording of at least one signal vector with at least one component, which vector contains information about the relative position of the partial systems (K;
M), from the signals of the detecting component (A),
estimation of values of the parameter set from the at least one signal vector,
derivation and provision of correction values, which reduce systematic measurement errors of the measuring instrument, from the values of the parameter set.

11 more elements

Method according to any of the preceding claims, characterized in that the parameter set contains at least one of the following parameters

axis d (d) of rotation of the partial system,
area K in which the mark of a partial system lies, at least one of the partial systems having a form which in particular is at least partly smooth and, for example, has one of the following shapes
disc
ring
sphere
cylinder,
position of the mark for example an angle α (α) for describing the position of a code line if the mark consists of a code having code lines which are applied radially to a partial system having a partly flat surface, preferably disc-shaped, in the plane of this surface, for example as a sequence of alternately transparent and opaque code lines or as a sequence of code lines having alternately different reflectivity,
position angle β (β) for describing the rotation of a partial system (K) about the axis d (d) of rotation relative to other partial systems,
position parameter of a radiation source if the imaging means (L) include one or more sources of electromagnetic radiation, in particular light sources,
position parameter of the point of intersection (D) of the axis d (d) of rotation with the area carrying the mark,
position parameter of a diode array if the detecting component (A) includes one or more arrays of photosensitive diodes, in particular in linear arrangement.

8 more elements

Method according to any of the preceding claims, characterized in that the parameter set includes at least one, preferably dimensionless and/or time-invariant, parameter which represents a logical combination of parameters, in particular from the mathematical model.

Method according to any of the preceding claims, characterized in that, before the conversion of the image of structural elements of the first partial system (K) into signals, the method includes, as an additional step, at least one further imaging of structural elements (S) of a partial system, which determine the relative position of a partial system, on at least one of the partial systems, in particular of the second partial system (M) on the first partial system (K), optionally a plurality of further images following one another in succession.

Dependencies are inferred from the claim text.

Method for calibrating a measuring instrument

Life of this patent

Method for calibrating a measuring instrument

Life of this patent

Abstract

Claims31