Method and device for the hysteresis correction of measured values for sensors with extensometers
AssigneeSchenck Process LLC
InventorHans Guenter Koenig
Life of this patent
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Abstract
A transducer including a deformation body with a strain gage produces hysteresis-affected measured values based on the strain of the deformation body. Each measured value is to be corrected by the hysteresis error. For this purpose, a hysteresis model is formed from a recorded loading characteristic curve and the theory of the dipole density of the oriented elementary dipoles in the interior of the deformation body. With the aid of the hysteresis model, and the determined hysteresis-affected measured values, and in connection with the acquired loading history, a correction value is derived and used to correct the hysteresis error.
Claims16
A method for the hysteresis correction of hysteresis-affected measured values in connection with at least one transducer with at least one strain gage, which detects the strain due to a force influence on an elastic deformation body, in which the hysteresis-affected measured values are corrected by a determined hysteresis error, characterized in that a hysteresis model of the transducer is formed in a model circuit from determined loading values of loading of the transducer in a rising loading branch and a falling loading branch of an envelope of the hysteresis and from a dipole density φ of oriented elementary dipoles in an interior of the deformation body, with the aid of which hysteresis model, a respective correction value that serves for the correction of the hysteresis error is derived or calculated for each one (x) of the hysteresis-affected measured values.
An apparatus for carrying out a method for the hysteresis correction of hysteresis-affected measured values in connection with at least one transducer with at least one strain gage, which detects the strain due to a force influence on an elastic deformation body, in which the hysteresis-affected measured values are corrected by a determined hysteresis error, wherein a hysteresis model is formed from determined loading values of loading of the transducer in a rising loading branch and a falling loading branch, with the aid of which hysteresis model, and from each determined hysteresis-affected measured value, a respective correction value is derived or calculated and serves for the correction of the hysteresis error, wherein the apparatus is characterized in that a transducer (1) with strain gages is provided, of which the hysteresis-affected measured values are delivered to a model circuit (3), which forms from said measured values an auxiliary value h, which is coupled in a provided multiplying circuit (5) with the weighting factor w formed from by a provided weighting circuit (4) to form a correction value, and from which, in a provided summing circuit (6), under consideration of a respective one of the hysteresis-affected measured values, at the output of which the corrected measured value y is made available for further processing or indication.
A method of processing a measured value output by a transducer including at least one strain gage on an elastic deformable body, comprising the steps:
- a) from said transducer, outputting a measured value based on a strain of said deformable body that is due to a force applied to said deformable body and that is detected by said at least one strain gage, wherein said measured value is affected by a hysteresis error caused by hysteresis of said strain that exhibits a hysteresis envelope having a rising loading curve and a falling loading curve;
- b) providing a hysteresis model of said hysteresis from determined sample loading values of a loading of said deformable body along both said rising loading curve and said failing loading curve, and based on a dipole density of oriented elementary dipoles in said deformable body;
- c) using said hysteresis model, determining a hysteresis correction value for said measured value;
- and
- d) applying, said hysteresis correction value or a derived value that is derived therefrom to said measured value to produce a corrected measured value from which said hysteresis error has been eliminated or reduced.
Dependencies are inferred from the claim text.