DE102020119723A1 - DEVICE AND METHOD FOR CALIBRATION OF A TRANSDUCER - Google Patents

Abstract

It is already known to calibrate a measuring sensor with a calibration device by holding the measuring sensor between a base module and a head module and successively introducing a force into various target pressure points in the head module in order to carry out a calibration in relation to different force axes and torque axes. However, this requires six measurements to calibrate a sensor. However, the advantage of this application is that crosstalk of the effect on one effective axis can be calculated out on other effective axes. The present invention is intended to accelerate these measurements. If there is no detection of crosstalk, a defined application of force can be used to calibrate on the basis of just a single introduction of force, in that a base adapter and a head adapter are each provided with geometrically specified receptacles, with which the introduced force has components in each effective axis.

Description

The present invention relates to a device for accommodating a sensor to be calibrated for force and moment measurement with multiple axes of action, comprising a base module and a head module, which hold the sensor between them, the sensor and an inclination sensor assigned to the head module being data-connected to an evaluation unit, and a method for calibrating a sensor.

Such a device and a corresponding method are already from DE 10 2018 110 814 B3 previously known. There it is provided to accommodate a measurement sensor, such as is used in vehicle impact tests, in a receiving device between a base module and a head module and to calibrate it by introducing forces at defined positions. If these forces are introduced eccentrically, so that the measuring sensor is twisted, measurement and calibration can also be carried out with regard to moments. However, the measurement setup changes continuously during the calibration due to material bending caused by the introduction of force, which is compensated for by an inclination sensor provided on the head module. The measured values of the inclination sensor are fed together with the measured values of the measuring sensor to an evaluation unit, in which the measuring sensor is calibrated on the basis of the plurality of measurements.

Due to the geometry of the recording device and the defined force application points, the forces are only applied in the defined direction through the geometric zero point of the measuring sensor without loading the other axes. In this way, the sensitivities of the sensor signal can be determined in the defined force axis. The signals measured in the non-loaded force axes result directly in the cross-sensitivities, i.e. crosstalk, of the measuring sensor due to its non-idealities.

When moments are introduced, i.e. eccentric force introduction, the forces are also introduced exclusively in the direction of the defined moment, without loading the other moment axes. However, the torque is always introduced with a force in a defined direction at a defined distance l _x , l _y , l _z on an effective axis from the geometric zero point of the measuring sensor. In this way, the sensitivities of the measuring sensor can be maintained in the defined moment axis. The signals measured in the axes that are not under load also result in the crosstalk of the measuring sensor due to its non-idealities. To determine the effects of crosstalk, the signal from the loaded force axis is subtracted accordingly.

Further prior art is from CN 101 587 003 A , the EP 2 246 675 A1 and the U.S. 7,730,776 B2 previously known.

Proceeding from this state of the art, the object of the present invention is to speed up the process of calibrating a measuring sensor and thus make it more efficient.

This is achieved by a device according to the features of independent claim 1 and by a method according to the features of independent claims 6 and 9. Useful configurations of both the device and the method can be found in the subsequent dependent claims.

According to the invention it is provided that essentially from the document DE 10 2018 110 814 B3 previously known recording device is used with the sensor inserted therein in order to position it in a defined manner. The sensor is accommodated in a manner known per se between a base module and a head module. In this case, the head module has an inclination sensor which, together with the outputs of the measuring transducer, is data-connected to an evaluation unit. However, instead of taking six separate measurements for the different axes of action, i.e. the force axes F _x , F _y , F _z and the moment axes M _x , M _y , M _z , the invention provides for the use of a base adapter to hold the base module and a head adapter to hold it of the head module of the recording device. The base adapter and head adapter each form a mechanical mount, the geometry of which determines the degree of force application into the respective effective axes when a single force is applied only to the head adapter, against the counterforce of the base adapter lying on it.

If the crosstalk of the sensor is not determined, then with the help of the base adapter and head adapter, a single application of force at just one point of the head adapter can be used to measure and calibrate the sensor with regard to all six axes of action F _x , F _y , F _z , M _x , M _y , M _z .

With some advantage, the geometry of the base adapter and head adapter can be used to define the force components that act on the individual effective axes and that have a defined distance l _x , l _y , l _{z from} the geometric zero point of the sensor. The position of the interposed receiving device results from the shape of the receptacles in the base adapter and the head adapter, into which the base module and the head module are inserted. This choice of angles in turn determines the force components and their proportions. As long as the distances l _x , l _y , l _{z are} each zero, no moments occur, there is a pure introduction of force. This would be the case with an equilateral tetrahedron-shaped receptacle in both the base and head adapter, with a cube-shaped receptacle and with the base and head adapter being aligned exactly one above the other.

In order to be able to address all axes of action, however, it makes more sense if all contact surfaces of the receptacles are inclined relative to a direction in which force is introduced into the base adapter and/or the head adapter. This is the case if they neither point in the same direction as the force application nor are they arranged exactly at right angles to it.

As a special case, the mounts in the base adapter and head adapter can also have a tetrahedral shape, but this should not be an equilateral tetrahedral shape, so that a moment can also be applied. The concept of the tetrahedron is also to be interpreted broadly. Insofar as a receptacle consists of wall sections into which a tetrahedron can be inscribed, these are regarded as tetrahedron-shaped within the meaning of the invention, even if the wall of the receptacle consists of three rectangles as a whole.

As already mentioned, it makes sense for the introduction of force into the torque axes if the adapters are offset from one another, ie the axes of the force introduction into the two adapters are offset from one another, in particular offset in parallel.

In such a case, the evaluation unit can then determine the ratios between the introduced force and the force components in the individual force axes based on the geometry of the receptacles and the resulting parallel offset of the adapter.

The ratios between the applied force and the torque components in the individual torque axes result accordingly, taking into account the defined distance l _x , l _y , l _{z of} the adapter from the zero point of the measuring sensor.

A corresponding introduction of force is also possible without the use of a base adapter and a head adapter, in that forces with several force components are introduced directly into the base module and the head module. In this case, however, the unit consisting of base module and head module would have to be rotated in between and the measurement would have to be divided into several measurements. However, there is the possibility of carrying out a measurement analogous to the invention without using the adapter.

The invention described above, in particular the calculation of the force and torque components, is explained in more detail below using an exemplary embodiment.

• 1 eine Aufnahmevorrichtung gemäß dem Stand der Technik mit einem Messaufnehmer, welcher zwischen einem Basismodul und einem Kopfmodul aufgenommen ist in perspektivischer Darstellung,
• 2 die Aufnahmevorrichtung gemäß 1, welche erfindungsgemäß zwischen einem Basisadapter und einem Kopfadapter aufgenommen ist in perspektivischer Darstellung, sowie
• 3 eine schematische Darstellung der Lage der Krafteinleitungspunkte an der Aufnahmevorrichtung im Koordinatensystem des Messaufnehmers in perspektivischer Darstellung.

Show it

• 1 a receiving device according to the prior art with a sensor, which is accommodated between a base module and a head module in a perspective view,
• 2 the recording device according to 1 , which is accommodated according to the invention between a base adapter and a head adapter in a perspective view, and
• 3 a schematic representation of the position of the force application points on the recording device in the coordinate system of the measuring transducer in a perspective representation.

1 shows a recording device 1 consisting of a base module 3 as part of a holding device for a sensor to be calibrated 1 and a head module 10, which under Zwischenstel ment of the sensor to be calibrated is attached to the base module. The base module 3 is essentially made up of a first flank 4, a second flank 5 and a third flank 6, which are each perpendicular to one another. The head module 10 is largely cube-shaped and has a receiving trough, not visible here, in which the measuring transducer can be inserted in a form-fitting manner. After the head module 10 has been rotated and then placed onto the base module 3, the recording device shown is ready for calibration. The connection cable 2 of the sensor 1 is led out to the side. An inclination sensor 12 is arranged on a third side surface 16, which detects an inclination of the head module 10 during the calibration process and which is connected via a connecting cable 13 to the evaluation unit, which communicates with the measurement sensor 1 and the calibration device 19.

While the calibration according to this solution from the prior art now takes place in six steps, in that the calibration device 19 runs through all target pressure points F _x , F _y , F _z , M _x , M _y , M _{z in} succession, a combination of one Base adapter 7 and a head adapter 11 used to hold the recording device 1. The receiving device 1 is held as a whole between the adapters in such a way that the base module 3 only contacts the base adapter 7 and the head module 10 only the head adapter 11. Both adapters 7 and 11 have tetrahedral receptacles, into which a corner of the base module 3 or of the Head module 10 are inserted. The corners, which are formed from the first flank 4, the second flank 5 and the third flank 6 in the base module 3, are used in the head module 10 from the first side surface 14, the second side surface 15 and the third side surface 16. This results in a defined position of the recording device 1, the geometry of which predetermines the distribution of force when a force is introduced via a target pressure point 9 on the adapter.

3 shows schematically the distribution of two points of introduction 17 and 18. The first point of introduction corresponds to the situation as shown in 2 is shown, the second initiation point is a position in which the receiving device 1 is rotated further around a corner in relation to the adapters 7 and 10 .

In the case of a symmetrical force application, the force application vector is determined $$\overrightarrow{{\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0}={\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\cdot \frac{1}{\sqrt{3}}\cdot \left(\begin{array}{c}1\\ 1\\ 1\end{array}\right)\text{With}{f}_{x,y,\mathrm{e.g}}=f_{nenn}\text{.}$$

In this case, the result is always the same value for $$f_{x,y,\mathrm{e.g}}={\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\cdot \frac{1}{\sqrt{3}}.$$

$$M_y=-l_z\cdot F_x+l_x\cdot F_z$$

$$M_z=-l_y\cdot F_x-l_x\cdot F_y$$

wobei M_y sich mit der obigen Bedingung zu Null addiert. Am zweiten Einleitungspunkt 18 hingegen bestimmt sich $$M_x=l_z\cdot F_y+l_y\cdot F_z$$

$$M_y=-l_z\cdot F_x-l_x\cdot F_z$$

$$M_z=-l_y\cdot F_x+l_x\cdot F_y$$

wobei sich in diesem Fall entsprechend M_z zu Null addiert. wird nun mit einer unsymmetrischen Krafteinleitung gearbeitet, so verändert sich die Berechnung wie folgt: $$\overrightarrow{F_0}=F_0\cdot \frac{1}{\sqrt{6}}\cdot \left(\begin{array}{c}1\\ 1\\ 2\end{array}\right)\text{mit}{F}_z=F_{nenn}\text{und}{F}_{x,y}=\frac{F_{nenn}}{2}$$

At the first initiation point 17 is determined $$M_x=l_{\mathrm{e.g}}\cdot f_y+l_y\cdot f_{\mathrm{e.g}}$$

$$M_y=-l_{\mathrm{e.g}}\cdot f_x+l_x\cdot f_{\mathrm{e.g}}$$

$$M_{\mathrm{e.g}}=-l_y\cdot f_x-l_x\cdot f_y$$

where M _y adds to zero with the above condition. At the second initiation point 18, however, is determined $$M_x=l_{\mathrm{e.g}}\cdot f_y+l_y\cdot f_{\mathrm{e.g}}$$

$$M_y=-l_{\mathrm{e.g}}\cdot f_x-l_x\cdot f_{\mathrm{e.g}}$$

$$M_{\mathrm{e.g}}=-l_y\cdot f_x+l_x\cdot f_y$$

where in this case correspondingly M _z adds up to zero. If you now work with an asymmetrical force application, the calculation changes as follows: $$\overrightarrow{{\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0}={\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\cdot \frac{1}{\sqrt{6}}\cdot \left(\begin{array}{c}1\\ 1\\ 2\end{array}\right)\text{With}{f}_{\mathrm{e.g}}=f_{nenn}\text{and}{f}_{x,y}=\frac{f_{nenn}}{2}$$

jedoch für $$F_z=F_0\cdot \frac{2}{\sqrt{6}}.$$

Here again the same value results for $$f_{x,y}=f_0\cdot \frac{1}{\sqrt{6}},$$

however for $$f_{\mathrm{e.g}}={\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\cdot \frac{2}{\sqrt{6}}.$$

$$M_y=-l_z\cdot F_x-l_x\cdot F_z$$

$$M_z=-l_y\cdot F_x+l_x\cdot F_y$$

kann sodann ein Zahlenbeispiel angegeben werden. Die folgende Tabelle enthält neben den sechs Wirkachsen F_x, F_y, F_z, M_x, M_y, M_z die Belastungen in dem Beispiel mit Achse Fx Fy Fz Mx My Mz Nennlast (kN) -8,90 8,90 -13,50 Nennlast (Nm) 282,6 282,6 282,7 zu $$\overrightarrow{F_0}=F_0\cdot \frac{1}{\sqrt{{\left(\mathrm{8,9}\right)}^2+{\left(\mathrm{8,9}\right)}^2+{\left(\mathrm{13,5}\right)}^2}}\cdot \left(\begin{array}{c}\mathrm{8,9}\\ \mathrm{8,9}\\ \mathrm{13,5}\end{array}\right)\text{mit}{F}_0=\mathrm{18,46}kN$$

also $$F_{x,y}=F_0\cdot \frac{\mathrm{8,9}}{\sqrt{{\left(\mathrm{8,9}\right)}^2+{\left(\mathrm{8,9}\right)}^2+{\left(\mathrm{13,5}\right)}^2}}$$

$$F_z=F_0\cdot \frac{\mathrm{13,5}}{\sqrt{{\left(\mathrm{8,9}\right)}^2+{\left(\mathrm{8,9}\right)}^2+{\left(\mathrm{13,5}\right)}^2}}$$

With the resulting moments $$M_x=l_{\mathrm{e.g}}\cdot f_y+l_y\cdot f_{\mathrm{e.g}}$$

$$M_y=-l_{\mathrm{e.g}}\cdot f_x-l_x\cdot f_{\mathrm{e.g}}$$

$$M_{\mathrm{e.g}}=-l_y\cdot f_x+l_x\cdot f_y$$

a numerical example can then be given. In addition to the six active axes F _x , F _y , F _z , M _x , M _y , M _{z ,} the table below contains the loads in the example axis fx fy vehicle Mx My Mz Nominal load (kN) -8.90 8.90 -13.50 Rated load (Nm) 282.6 282.6 282.7 to $$\overrightarrow{{\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0}={\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\cdot \frac{1}{\sqrt{{\left(8.9\right)}^2+{\left(8.9\right)}^2+{\left(13.5\right)}^2}}\cdot \left(\begin{array}{c}8.9\\ 8.9\\ 13.5\end{array}\right)\text{With}{\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0=18.46kN$$

so $$f_{x,y}={\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\cdot \frac{8.9}{\sqrt{{\left(8.9\right)}^2+{\left(8.9\right)}^2+{\left(13.5\right)}^2}}$$

$$f_{\mathrm{e.g}}={\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="DE102020119723A1\_0025.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\cdot \frac{13.5}{\sqrt{{\left(8.9\right)}^2+{\left(8.9\right)}^2+{\left(13.5\right)}^2}}$$

$$M_y=-l_z\cdot F_x-l_x\cdot F_z=0Nm$$

$$M_z=-l_y\cdot F_x+l_x\cdot F_y=-\mathrm{282,6}Nm$$

und für den zweiten Einleitungspunkt 18 $$M_x=l_z\cdot F_y+l_y\cdot F_z=\mathrm{282,6}Nm$$

$$M_y=-l_z\cdot F_x-l_x\cdot F_z=-\mathrm{282,6}Nm$$

$$M_z=-l_y\cdot F_x+l_x\cdot F_y=0Nm$$

bei l_x,y = 10,5 mm und l_z = 15,9 mm.This results in 17 for the first initiation point $$M_x=l_{\mathrm{e.g}}\cdot f_y+l_y\cdot f_{\mathrm{e.g}}=282.6Nm$$

$$M_y=-l_{\mathrm{e.g}}\cdot f_x-l_x\cdot f_{\mathrm{e.g}}=0Nm$$

$$M_{\mathrm{e.g}}=-l_y\cdot f_x+l_x\cdot f_y=-282.6Nm$$

and for the second initiation point 18 $$M_x=l_{\mathrm{e.g}}\cdot f_y+l_y\cdot f_{\mathrm{e.g}}=282.6Nm$$

$$M_y=-l_{\mathrm{e.g}}\cdot f_x-l_x\cdot f_{\mathrm{e.g}}=-282.6Nm$$

$$M_{\mathrm{e.g}}=-l_y\cdot f_x+l_x\cdot f_y=0Nm$$

at l _x,y = 10.5 mm and l _z = 15.9 mm.

A device for accommodating a sensor to be calibrated for measuring force and torque with a plurality of effective axes and a method for calibrating a sensor are described above, in which the process of calibrating a sensor is to be accelerated by a single measurement with the aid of adapters and is therefore more efficient design.

Reference List

1

recording device

2

Sensor connection cable

3

base module

4

first flank

5

second flank

6

third flank

7

base adapter

8th

adapter plate

9

adapter target pressure point

10

head module

11

head adapter

12

tilt sensor

13

Inclination sensor connection cable

14

first face

15

second side face

16

third side face

17

first introductory point

18

second initiation point

19

calibration device

20

Pressure piece

fx

first centric target pressure point

fy

second centric target pressure point

vehicle

third centric target pressure point

Mx

first eccentric target pressure point

My

second eccentric target pressure point

Mz

third eccentric target pressure point

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018110814 B3 [0002, 0008]
• CN 101587003A [0005]
• EP 2246675 A1 [0005]
• US 7730776 B2 [0005]

Claims (9)

Device for accommodating a measuring sensor to be calibrated for measuring force and moment with several axes of action, comprising a base module (3) and a head module (10) which hold the measuring sensor between them, the measuring sensor and an inclination sensor (12 ) are data-connected to an evaluation unit, characterized in that the base module (3) is accommodated in a receptacle of a base adapter (7) and the head module (10) is accommodated in a receptacle of a head adapter (11) in such a way that a force is introduced into the base adapter (7 ) and the head adapter (11) simultaneously includes force components in the direction of all effective axes of the sensor. Device according to claim 1 , characterized in that the base adapter (7) and the head adapter (11) assume a defined distance from a geometric zero point on all active axes. Device according to one of Claims 1 or 2 , characterized in that all contact surfaces of the receptacles are inclined relative to a force introduction direction in the base adapter (7) and/or the head adapter (11). Device according to claim 3 , characterized in that the receptacles in the base adapter (7) and head adapter (11) are tetrahedrally shaped. Device according to one of the preceding claims, characterized in that an axis of force introduction into the head module (10) is shifted in parallel with respect to an axis of force introduction into the base module (3). Method for calibrating a measuring sensor for force and moment measurement with several effective axes, the measuring sensor being fixed between a base module (3) and a head module (10) and a force being applied in the direction of the base module (3) to the head module by a calibration device (19). (10) is initiated, with measured values of the measuring sensor and an inclination sensor (12) assigned to the head module (10) and control values of the calibration device (19) being fed to an evaluation unit, which uses these data to calibrate the measuring sensor, characterized in that the The base module (3) is accommodated in a base adapter (7) and the head module (10) in a head adapter (11) in such a way that force is introduced into the base adapter (7) and the head adapter (11) at the same time as force components in the direction of all Includes effective axes of the sensor and the evaluation unit due to this force application, waiving e Ine consideration of crosstalk between the axes of action, a simultaneous calibration of the sensor with respect to all axes of action. procedure according to claim 6 , characterized in that the geometry of the mounts and a parallel offset between the base adapter (7) and the head adapter (11) specifies the ratios between an introduced force and the force components in the individual force axes. procedure according to claim 7 , characterized in that the evaluation unit determines the torque components in the individual torque axes from the force components in the individual force axes, taking into account a defined distance which the base adapter (7) and the head adapter (11) assume on all active axes from a geometric zero point. Method for calibrating a measuring sensor for force and moment measurement with several effective axes, the measuring sensor being fixed between a base module (3) and a head module (10) and a force being applied in the direction of the base module (3) to the head module by a calibration device (19). (10) is initiated, with measured values of the measuring sensor and an inclination sensor (12) assigned to the head module (10) and control values of the calibration device (19) being fed to an evaluation unit, which uses this data to calibrate the measuring sensor, characterized in that a The introduction of force into the base adapter (7) and the head adapter (11) simultaneously includes force components in the direction of several effective axes of the measuring sensor and the evaluation unit carries out a simultaneous calibration of the measuring sensor with regard to all effective axes on the basis of this force introduction, without taking crosstalk between the effective axes into account .

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