DE102018008231A1 - Method for measuring an axle geometry of a vehicle - Google Patents

Abstract

The invention relates to a method for measuring an axle geometry of a vehicle (1) having a front axle with two vehicle wheels (4) and a rear axle with two vehicle wheels (4), wherein positions of wheel centers of the vehicle wheels (4) rear left (HL), rear right (HR), front left (VL) and front right (VR) are measured with a resource, wherein a center of the rear axle (HM) corresponds to a sum of each half of the positions rear left (HL) and rear right (HR) a center of the frontal axis (VM) corresponds to a sum of each half of the front left (VL) and front right (VR) positions, where an orthogonal basis comprises a chassis symmetry axis, a rear axis symmetry axis, and a vertical vector using the centers (HM, VM) and the Gram-Schmidt orthonormalization method is created, wherein a coordinate system of the resource centered in the respective wheel center and measuring points (RF, RF) of a Linkage under wheel-individual shifting of the equipment due to the centering of the coordinate system in a plane (E), which is defined, is measured, so that the link () passes through the origin of the coordinate system and in a plane, wherein the plane (E) with a plane (Exz) of the resource is cut and a resulting line of intersection describes a travel of the resource, the toe angle (φ) being the angle between the intersection line which contains the link (and the chassis axis of symmetry.

Description

The invention relates to a method for measuring an axle geometry of a vehicle.

Measurements of the axle geometry, in particular toe angles and camber angles, of vehicles are required during the manufacture and repair of vehicles. If a vehicle track level is unknown or if a vehicle level is not parallel to a resource plane (for example, slope / incline / other inclinations), the measurement result of the toe angle is falsified by the influence of the camber angle. The same applies to the measurement error due to the influence of the toe angle on the camber angle. Already at very low imbalances of the vehicle to the equipment, the measurement result is significantly distorted.

From the DE 10 2017 002 891 A1 a method for determining a chassis geometry of a motor vehicle is known, with a measuring device having at least one sensor for detecting environmental data. By means of the sensors, a measurement of a wheel flange or a wheel hub is carried out, which contributes to the determination of the chassis geometry.

The invention is based on the object of specifying an improved method for measuring an axle geometry of a vehicle.

The object is achieved by a method having the features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

In a method according to the invention for measuring an axle geometry of a vehicle having a front axle with two wheels and a rear axle with two wheels positions of Radmittelpunkten the wheels rear left, rear right, front left and front right with a resource measured, with a center of the rear axle of a Sum of half of each of the rear left and rear right positions, wherein a center of the front axle corresponds to a sum of half of the front left and front right positions, respectively, with an upper normal base including a chassis symmetry axis, a rear axis symmetry axis, and a vertical vector using the Center points and the Gram-Schmidt Orthonormierungsverfahren is created, wherein a coordinate system of the resource centered in the respective wheel center and measuring points of a link under individual wheel displacement of the equipment due to the centering of the K coordinate system is measured in a plane defined by, so that the link passes through the origin of the coordinate system and lies in a plane, wherein the plane is intersected with a plane of the resource and a resulting intersection line describes a travel path of the resource wherein the toe angle is the angle that results between the intersection line containing the link and the chassis axis of symmetry.

By means of the method according to the invention, the correct vehicle track plane is determined via a wheel center point measurement, so that the skew between the vehicle track plane and the equipment plane can be compensated. By means of a suitable coordinate transformation from the world coordinate system (operating medium) into the vehicle coordinate system, the correct measuring level for the operating medium is determined. The determined measuring plane is now parallel to the vehicle track plane and allows a correct measurement of the chassis geometry.

• • Messung der Fahrwerksgeometrie unabhängig von der Lage des Fahrzeugs (z. B. Steigung/Gefälle/sonstige Neigungen),
• • präzises Vermessen der fahrbahnunabhängigen sowie radindividuellen Fahrwerksgeometrie,
• • Erweiterung und Präzisierung der allgemeingültigen Spur- und Sturzwinkeldefinition,
• • Mathematisch exakte Modellierung der Fahrwerksgeometrie (insbesondere Fahrwerkssymmetrieachsen und Fahrwerkswinkel) im dreidimensionalen Raum,
• • allen aktiv beweglichen Betriebsmitteln, eine korrekte Fahrwerksgeometrievermessung trotz Fahrzeugschieflage durchzuführen.

The method according to the invention allows:

• • Measurement of the chassis geometry, regardless of the position of the vehicle (eg slope / slope / other inclinations),
• Precise measurement of the road-independent and wheel-specific chassis geometry,
• • extension and specification of the general track and camber angle definition,
• • mathematically exact modeling of the chassis geometry (in particular chassis symmetry axes and suspension angle) in three-dimensional space,
• • all actively moving equipment to carry out a correct suspension geometry measurement despite vehicle misalignment.

Embodiments of the invention are explained in more detail below with reference to drawings.

• 1 eine schematische Ansicht eines Fahrzeugs, einer Fahrzeugbahnebene und einer Betriebsmittelebene eines Betriebsmittels zum Vermessen einer Achsgeometrie des Fahrzeugs,
• 2 eine schematische Ansicht eines Fahrzeugs, einer Fahrzeugbahnebene und einer Betriebsmittelebene eines Betriebsmittels zum Vermessen einer Achsgeometrie des Fahrzeugs wobei die Fahrzeugbahnebene zur Betriebsmittelebene stark schiefgestellt ist,
• 3 eine schematische Ansicht geometrischer Verhältnisse an einer Achse eines Fahrwerks eines Fahrzeugs,
• 4 den Verlauf eines Spurwinkels entlang einer Umdrehung einer Schnittgeraden in Abhängigkeit zur Schieflage der Fahrzeugbahnebene,
• 5 ein Schema zur Definition des Spurwinkels,
• 6 ein Schema zur Definition des Sturzwinkels,
• 7 eine Ansicht eines Fahrzeugs von unten,
• 8 eine schematische Ebenendarstellung von Rad- und Achsmittelpunkten,
• 9 eine schematische Darstellung einer Orthonormalbasis für die Fahrwerksgeometrievermessung,
• 10 eine schematische Darstellung einer Orthonormalbasis und einer Ebene eines Verfahrwegs eines Betriebsmittels,
• 11 eine schematische Seitenansicht eines Laserverfahrwegs, und
• 12 eine schematische Darstellung von Ebenen für die Berechnung des Spurwinkels.

Showing:

• 1 1 is a schematic view of a vehicle, a vehicle track plane and a resource plane of a resource for measuring an axle geometry of the vehicle;
• 2 1 is a schematic view of a vehicle, a vehicle track plane and a resource plane of a resource for measuring an axle geometry of the vehicle, wherein the vehicle track plane is greatly skewed to the resource plane,
• 3 a schematic view of geometric relationships on an axle of a chassis of a vehicle,
• 4 the course of a toe angle along a rotation of a cutting line as a function of the tilt of the vehicle track plane,
• 5 a scheme for defining the toe angle,
• 6 a scheme for defining the camber angle,
• 7 a view of a vehicle from below,
• 8th a schematic level representation of wheel and axle centers,
• 9 a schematic representation of an orthonormal basis for the chassis geometry measurement,
• 10 a schematic representation of a Orthonormalbasis and a plane of travel of a resource,
• 11 a schematic side view of a laser path, and
• 12 a schematic representation of planes for the calculation of the toe angle.

Corresponding parts are provided in all figures with the same reference numerals.

1 is a schematic view of a vehicle 1 , a vehicle level 2 and a resource level 3 , a resource for measuring an axle geometry of the vehicle 1 ,

In the case of normal equipment, ie chassis geometry measurement equipment, it is assumed that the vehicle 1 and the equipment is aligned parallel to the horizon.

In a conventional chassis geometry measurement system for workshop use or for the production of vehicles 1 is the vehicle 1 on a lift and stands on floating turntables to eliminate tension from the chassis. Neither the plant nor the vehicle 1 are able to detect a misalignment and / or compensate it correctly, because the system metrology does not have the appropriate degrees of freedom of movement.

Is a misalignment between the vehicle level 2 and resource level 3 given, it comes to large systematic errors in the measurement.

2 is a schematic view of a vehicle 1 , a vehicle level 2 and a resource level 3 a resource for measuring an axle geometry of the vehicle 1 the vehicle track plane 2 to the resource level 3 is strongly skewed.

In extreme cases, when the vehicle 1 inclined at 90 ° to the horizon as in 2 , the camber angle is measured instead of the toe angle.

In 1 is the resource level 3 parallel to the vehicle level 2 aligned. Track and camber angles are measured correctly. In 2 an extreme case is presented for clarification. Here is the vehicle level 2 opposite the resource level 3 inclined by 90 °. The equipment measures the camber angle of the vehicle in this extreme case 1 and outputs this as a toe angle. The measured toe angle of the vehicle 1 is erroneously output as a camber angle. This extreme case is intended to illustrate the meaning of this relationship vividly. In reality, these are much smaller skew angles. Already at 1 ° tilt of the vehicle 1 to the horizon (assumption: equipment is aligned parallel to the horizon) or at 1 ° imbalance of the vehicle level 2 to the resource level 3 the toe angle in design zero position is measured incorrectly by 0.033 ° (example Mercedes-Benz S-Class BR222, wheelbase 3165 mm, track and camber angle adjusted according to the test specification)

• „Projektion des Winkels zwischen der Fahrzeuglängsachse und der Radebene in der Fahrbahnebene.“ [Henker, Erich: Fahrwerktechnik; Vieweg; 1993]
• „Der Winkel zwischen den Schnittlinien der Radmittelebenen beider Räder mit der Fahrbahnebene ohne Lenkeinschlag.“ [Heißing, Bernd: Fahrwerkhandbuch; Springer; 20 13]
• „Winkel zwischen der XV-Achse und der Radmittelebene um die ZV-Achse; das Fahrzeug befindet sich im Stand und die Lenkung in Geradeausstellung.“ [DIN ISO 8855 - Straßenfahrzeuge - Fahrzeugdynamik und Fahrverhalten - Begriffe; 20 13]

For the method according to the invention, a new, more precise definition of the toe angle δ introduced. So far, the toe angle δ defined as follows:

• "Projection of the angle between the vehicle longitudinal axis and the wheel plane in the road level." [Henker, Erich: Fahrwerktechnik; Vieweg; 1993]
• "The angle between the cutting lines of the wheel center planes of both wheels with the road surface without steering angle." [Heißing, Bernd: Fahrwerkhandbuch; Springer; 20 13]
• "Angle between the XV-axis and the wheel center plane around the ZV-axis; the vehicle is stationary and the steering is in the straight-ahead position. "[DIN ISO 8855 - Road vehicles - Vehicle dynamics and handling - Terms and definitions; 20 13]

3 schematically shows geometric relationships on an axle of a chassis of a vehicle 1 , Pictured are two vehicle wheels 4 an axle with respective stub axles 5 , In straight ahead position of the vehicle wheels 4 gives way to a Raddrehebene 6 every vehicle wheel 4 around the toe angle δ from a parallel to the vehicle's longitudinal axis X off, leaving a gap C between the vehicle wheels 4 at her in the direction of travel F front end is less than a distance B between the vehicle wheels 4 at her in the direction of travel F rear end.

$$\begin{array}{cc}\mathrm{\beta }=& {\text{cos}}^2\left(\vartheta \right)+\frac{si{n}^2\left(\phi \right)}{co{s}^2\left(\phi \right)}co{s}^2{}^{\left(\gamma \right)}si{n}^2\left(\vartheta \right)si{n}^2\left(\phi \right)+2\frac{si{n}^2\left(\phi \right)}{co{s}^2\left(\phi \right)}\text{cos}\left(\gamma \right)\text{sin}\left(\vartheta \right)\text{sin}\left(\phi \right)\text{sin}\left(\gamma \right)\text{cos}\left(\vartheta \right)\\ & +\frac{si{n}^2\left(\phi \right)}{co{s}^2\left(\phi \right)}si{n}^2{}^{\left(\gamma \right)}co{s}^2\left(\vartheta \right)+co{s}^2{}^{\left(\gamma \right)}si{n}^2\left(\vartheta \right)co{s}^2\left(\phi \right)+2si{n}^3\left(\phi \right)co{s}^3{}^{\left(\gamma \right)}si{n}^3\left(\vartheta \right)\\ & +2\text{sin}\left(\phi \right)\text{cos}\left(\gamma \right)\text{sin}\left(\vartheta \right)\text{sin}\left(\gamma \right)\text{cos}\left(\vartheta \right)\end{array}$$

$${\text{Spurwinkel}}_{\text{gemessen}}\left(\mathrm{\phi },\mathrm{\vartheta },\mathrm{\gamma }\right)=arcsin\left(\frac{\frac{\text{sin}\left(\phi \right)}{\text{cos}\left(\phi \right)}\left(\text{sin}\left(\gamma \right)\text{sin}\left(\vartheta \right)\text{sin}\left(\phi \right)-\text{cos}\left(\gamma \right)\text{cos}\left(\vartheta \right)\right)+\text{sin}\left(\gamma \right)\text{sin}\left(\vartheta \right)\text{cos}\left(\phi \right)}{\sqrt{\mathrm{\alpha }}}\right)$$

$${\text{Spurwinkel}}_{\text{gemessen}}\left(\mathrm{\phi },\mathrm{\vartheta },\mathrm{\gamma }\right)=arcsin\left(\frac{\frac{\text{sin}\left(\phi \right)}{\text{cos}\left(\phi \right)}\left(\text{cos}\left(\gamma \right)\text{sin}\left(\vartheta \right)\text{sin}\left(\phi \right)+\text{sin}\left(\gamma \right)\text{cos}\left(\vartheta \right)\right)+\text{cos}\left(\gamma \right)\text{sin}\left(\vartheta \right)\text{cos}\left(\phi \right)}{\sqrt{\mathrm{\beta }}}\right)$$

α

Schnittgeradenkoeffizient für Spurwinkelmessung

β

Schnittgeradenkoeffizient für Sturzwinkelmessung

φ

tatsächlicher Spurwinkel

ϑ

tatsächlicher Sturzwinkel

γ

Fahrzeugschieflage

The measurement method according to the invention as well as the equipment including mathematical calculation model are able to detect any inclinations and vehicle misalignments (rotation around all vehicle axes) and to initiate a correspondingly correct measurement. So it's not just the in 2 shown tilt or rotation about the vehicle Y-axis (transverse axis) compensated but also rotations around the vehicle X Axis (longitudinal axis) and rotations about the vehicle Z-axis (vertical axis). A compensation of this imbalance can only be carried out by an active movement of the equipment. Compensation for the behavior of the lane and camber values is possible, but with errors. The systematically made error in the measurement can be approximated by a mathematical model and compensated proportionately by the wheel rotation 6 with the vehicle level 2 , which is centered in the wheel center, is cut. The parameterized cutting line determines the points to be measured on the measurement object for the chassis geometry measurement. Provided the imbalance of the vehicle 1 is known, the erroneously measured values for the camber and camber angles can be converted to the correct values using the following system of equations with sufficient accuracy. $$\begin{array}{cc}\mathrm{\alpha }=& {\text{cos}}^2\left(\theta \right)+\frac{si{n}^2\left(\phi \right)}{cO{s}^2\left(\phi \right)}si{n}^2\left(\gamma \right)si{n}^2\left(\theta \right)si{n}^2\left(\phi \right)-2\frac{si{n}^2\left(\phi \right)}{cO{s}^2\left(\phi \right)}\text{sin}\left(\gamma \right)\text{sin}\left(\theta \right)\text{sin}\left(\phi \right)\text{cos}\left(\gamma \right)\text{cos}\left(\theta \right)\\ & +\frac{si{n}^2\left(\phi \right)}{cO{s}^2\left(\phi \right)}cO{s}^2\left(\gamma \right)cO{s}^2\left(\theta \right)+si{n}^2\left(\gamma \right)si{n}^2\left(\theta \right)cO{s}^2\left(\phi \right)+2si{n}^3\left(\phi \right)si{n}^3\left(\gamma \right)si{n}^3\left(\theta \right)\\ & -2\text{sin}\left(\phi \right)\text{sin}\left(\gamma \right)\text{sin}\left(\theta \right)\text{cos}\left(\gamma \right)\text{cos}\left(\theta \right)\end{array}$$

$$\begin{array}{cc}\mathrm{\beta }=& {\text{cos}}^2\left(\theta \right)+\frac{si{n}^2\left(\phi \right)}{cO{s}^2\left(\phi \right)}cO{s}^2{}^{\left(\gamma \right)}si{n}^2\left(\theta \right)si{n}^2\left(\phi \right)+2\frac{si{n}^2\left(\phi \right)}{cO{s}^2\left(\phi \right)}\text{cos}\left(\gamma \right)\text{sin}\left(\theta \right)\text{sin}\left(\phi \right)\text{sin}\left(\gamma \right)\text{cos}\left(\theta \right)\\ & +\frac{si{n}^2\left(\phi \right)}{cO{s}^2\left(\phi \right)}si{n}^2{}^{\left(\gamma \right)}cO{s}^2\left(\theta \right)+cO{s}^2{}^{\left(\gamma \right)}si{n}^2\left(\theta \right)cO{s}^2\left(\phi \right)+2si{n}^3\left(\phi \right)cO{s}^3{}^{\left(\gamma \right)}si{n}^3\left(\theta \right)\\ & +2\text{sin}\left(\phi \right)\text{cos}\left(\gamma \right)\text{sin}\left(\theta \right)\text{sin}\left(\gamma \right)\text{cos}\left(\theta \right)\end{array}$$

$${\text{toe angle}}_{\text{measured}}\left(\mathrm{\phi }.\mathrm{\theta }.\mathrm{\gamma }\right)=arcsin\left(\frac{\frac{\text{sin}\left(\phi \right)}{\text{cos}\left(\phi \right)}\left(\text{sin}\left(\gamma \right)\text{sin}\left(\theta \right)\text{sin}\left(\phi \right)-\text{cos}\left(\gamma \right)\text{cos}\left(\theta \right)\right)+\text{sin}\left(\gamma \right)\text{sin}\left(\theta \right)\text{cos}\left(\phi \right)}{\sqrt{\mathrm{\alpha }}}\right)$$

$${\text{toe angle}}_{\text{measured}}\left(\mathrm{\phi }.\mathrm{\theta }.\mathrm{\gamma }\right)=arcsin\left(\frac{\frac{\text{sin}\left(\phi \right)}{\text{cos}\left(\phi \right)}\left(\text{cos}\left(\gamma \right)\text{sin}\left(\theta \right)\text{sin}\left(\phi \right)+\text{sin}\left(\gamma \right)\text{cos}\left(\theta \right)\right)+\text{cos}\left(\gamma \right)\text{sin}\left(\theta \right)\text{cos}\left(\phi \right)}{\sqrt{\mathrm{\beta }}}\right)$$

α

Cutting line coefficient for toe angle measurement

β

Cutting line coefficient for camber angle measurement

φ

actual toe angle

θ

actual camber angle

γ

Vehicle misalignment

The actual toe and camber angles are implicitly described by the established system of equations. 4 shows by way of example the course of the toe angle along a rotation of the cutting line in dependence on the tilt of the vehicle track plane 2 ,

• - Lasertriangulationssensor,
• - Autokollimator,
• - Laserlinienscanner, Laserscanner,
• - Kamera mit Bildverarbeitungssystem,
• - chromatisch-konfokale Sensoren,
• - kapazitive Wegsensoren,
• - magneto-induktive Wegsensoren.

The invention relates to a novel method for roadway-independent and wheel-specific suspension geometry measurement. This method can be used with movable measuring sensors of all kinds, which are suitable for a chassis geometry measurement. The following sensors are considered:

• - laser triangulation sensor,
• - autocollimator,
• - laser line scanners, laser scanners,
• - camera with image processing system,
• - chromatic-confocal sensors,
• - capacitive displacement sensors,
• - Magneto-inductive displacement sensors.

The movement in the space of the sensors can be done by any resources, such as linear axes, hexapods or other spatial motion machines. Another component of the invention is the new and more precise and also generally accepted definition of the toe angle:
"The toe angle is defined as the angle between the cut line G the Raddrehebene 6 with the vehicle level 2 and the intersection line of the chassis symmetry plane with the vehicle track plane 2 . "

5 shows this with the example of a vehicle wheel 4 , The vehicle level 2 is shifted to the height of the wheel center. The chassis symmetry plane and the corresponding intersection line to the vehicle track plane 2 are not shown.

"The camber angle is defined as the angle between the cut line g2 the Raddrehebene 6 with a vertical plane 7 to the vehicle level 2 and the suspension symmetry plane. "

6 shows the Raddrehebene 6 , the vertical plane 7 to the vehicle level 2 and the cutting line g2 , wherein the chassis symmetry plane is not shown.

definiert, wobei $\overrightarrow{g}$

die Schnittgerade zwischen der Fahrzeugbahnebene 2 und der Raddrehebene 6 ist und $\overrightarrow{e_1}$

der Verbindungsvektor zwischen den Achsmittelpunkten der Vorder- und Hinterachse darstellt.Mathematically, the toe angle is called $\phi =\sphericalangle \left(\overrightarrow{G}.\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}\right)=arccOs\left(\frac{\overrightarrow{G}*\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}}{\left|\overrightarrow{G}\right|*\left|\overrightarrow{e}\right|}\right)$

defined, where $\overrightarrow{G}$

the cutting line between the vehicle track plane 2 and the wheel turning plane 6 is and $\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}$

represents the connection vector between the axle centers of the front and rear axles.

7 shows toe angles and chassis symmetry axes on a vehicle 1 and clearly illustrates the new definition. The vehicle 1 has a chassis symmetry axis e ₁ , a rear axle symmetry axis e ₂ , a toe angle φ , a cutting line G , and a geometric axis j in so-called Dachshund on. In the Dackellauf the toe angle of the rear axle is set so that the vehicle 1 Drifts sideways when driving, for example when the toe angle φ one of the vehicle wheels 4 the axis of the toe angle φ of the other vehicle wheel 4 deviates from the same axis.

und einem dritten senkrechten Vektor $\overrightarrow{e_3}$

(nicht dargestellt, zeigt aus der Zeichenebene heraus) gezeigt. Dies ist jedoch nicht immer der Fall. Das neue Verfahren erstellt diese Orthonormalbasis, sodass die oben genannte Definition anwendbar ist. Dies wird erreicht, indem der Vektor $\overrightarrow{e_2}$

der Hinterachssymmetrieachse e₂ orthogonal zu $\overrightarrow{e_1}$

und einem beliebigen senkrechten Vektor $\overrightarrow{e_3}$

gestellt wird. Dies ist möglich und hat keinen Einfluss auf den Spurwinkel φ, da der Spurwinkel φ nur zwischen $\overrightarrow{g}\text{ und }\overrightarrow{e_1}$

bestimmt wird.The mathematically defined relationship is applicable only in an orthonormal basis. In 7 is an orthonormal basis $\stackrel{}{e_{}}$$\overrightarrow{{}_1}.\overrightarrow{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}$

and a third vertical vector $\overrightarrow{e_3}$

(not shown, pointing out of the drawing plane). However, this is not always the case. The new procedure creates this orthonormal base so that the above definition is applicable. This is achieved by the vector $\stackrel{}{e_{}}$$\overrightarrow{{}_2}$

the rear axle symmetry axis e ₂ orthogonal to $\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}$

and any vertical vector $\overrightarrow{e_3}$

is provided. This is possible and has no influence on the toe angle φ because of the toe angle φ only between $\overrightarrow{G}\text{and}\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}$

is determined.

nach Konstruktion des Koordinatensystems $\left(\overrightarrow{e_1},\overrightarrow{e_2},\overrightarrow{e_3}\right),$

ist. Insbesondere ist die Fahrwerkssymmetrieebene genau span $\left(\overrightarrow{e_1},\overrightarrow{e_3}\right).$

Furthermore, the suspension axis of symmetry e ₁ or the chassis symmetry plane perpendicular to the vehicle track plane 2 runs and contains the connection path of the axis centers. In addition, it applies that the connection distance of the axis center points depends linearly $\overrightarrow{e_1}.$

after construction of the coordinate system $\left(\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}.\overrightarrow{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}.\overrightarrow{e_3}\right).$

is. In particular, the chassis symmetry plane is exactly span $\left(\overrightarrow{e_1}.\overrightarrow{e_3}\right),$

The procedure of the method is divided into the following steps:

1. The coordinates of the wheel centers at the rear left HL , back right MR , Left in the front VL and front right VR are measured with the resource in the resource coordinate system.

2. The coordinates of the wheel centers are used around the centers of the front axle VM and the rear axle HM to determine. In this case, the coordinates of the center point of the rear axle are HM = 1 / 2HL + 1 / 2HR and the coordinates of the center point of the front axle VM = 1 / 2VL + 1 / 2VR. 8th illustrates this definition.

$${\overline{\tilde{e}}}_2=\frac{\text{HL}-\text{HM}}{\left|\text{HL}-\text{HM}\right|}\text{ oder }{\overline{\tilde{e}}}_2=\frac{\text{HL}-\text{HR}}{\left|\text{HL}-\text{HR}\right|}$$

analog dazu ${\overline{\tilde{e}}}_2$

für die Vorderachse $$\overrightarrow{e_2}=\sqrt{\frac{1}{1-\langle {\text{e}}_1|\overrightarrow{\widetilde{e_2}}\rangle }}\ast \overrightarrow{\widetilde{e_2}}-\sqrt{\frac{{\langle \overrightarrow{{\text{e}}_1}|\overrightarrow{\widetilde{e_2}}\rangle }^2}{1-\langle \overrightarrow{{\text{e}}_1}|\overrightarrow{\widetilde{e_2}}\rangle }}\ast \overrightarrow{{\text{e}}_1}$$

mit Gram-Schmidtschem Orthonormierungsverfahren. $$\overrightarrow{e_3}=\left(\overrightarrow{e_1}\times \overrightarrow{e_2}\right)=\left(\begin{array}{c}{\text{e}}_{1\text{y}}{\text{e}}_{2\text{z}}-{\text{e}}_{1\text{z}}{\text{e}}_{2\text{y}}\\ {\text{e}}_{1\text{z}}{\text{e}}_{2\text{x}}-{\text{e}}_{1\text{x}}{\text{e}}_{2\text{z}}\\ {\text{e}}_{1\text{x}}{\text{e}}_{2\text{y}}-{\text{e}}_{1\text{y}}{\text{e}}_{2\text{x}}\end{array}\right)$$

Die Orthonormalbasis sowie alle Vektoren sind in 9 dargestellt, wobei RF₁ und RF₂ die Messpunkte für Fahrwerksgeometrievermessung auf dem Messobjekt darstellen.3. Set up the orthonormal base e1, e2, e3 using the previously determined axle centers. $${\overline{e}}_1=\frac{\text{VM}-\text{HM}}{\left|\text{VM}-\text{HM}\right|}$$

$${\overline{\tilde{e}}}_2=\frac{\text{HL}-\text{HM}}{\left|\text{HL}-\text{HM}\right|}\text{or}{\overline{\tilde{e}}}_2=\frac{\text{HL}-\text{MR}}{\left|\text{HL}-\text{MR}\right|}$$

Similarly ${\overline{\tilde{e}}}_2$

for the front axle $$\stackrel{}{e_{}}$$$$\overrightarrow{{}_2}=\sqrt{\frac{1}{1-<{\text{<figure-callout id="1" label="e" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">e</figure-callout>}}_1|\overrightarrow{\stackrel{~}{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}}>}}*\overrightarrow{\stackrel{~}{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}}-\sqrt{\frac{{<\overrightarrow{{\text{<figure-callout id="1" label="e" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">e</figure-callout>}}_1}|\overrightarrow{\widetilde{e_2}}>}^2}{1-<\overrightarrow{{\text{<figure-callout id="1" label="e" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">e</figure-callout>}}_1}|\overrightarrow{\widetilde{e_2}}>}}*\overrightarrow{{\text{<figure-callout id="1" label="e" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">e</figure-callout>}}_1}$$

with Gram-Schmidt orthonormation method. $$\overrightarrow{e_3}=\left(\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}\times \overrightarrow{e_2}\right)=\left(\begin{array}{c}{\text{e}}_{1\text{y}}{\text{e}}_{2\text{z}}-{\text{e}}_{1\text{z}}{\text{e}}_{2\text{y}}\\ {\text{e}}_{1\text{z}}{\text{e}}_{2\text{x}}-{\text{e}}_{1\text{x}}{\text{e}}_{2\text{z}}\\ {\text{e}}_{1\text{x}}{\text{e}}_{2\text{y}}-{\text{e}}_{1\text{y}}{\text{e}}_{2\text{x}}\end{array}\right)$$

The orthonormal base and all vectors are in 9 shown, where RF ₁ and RF ₂ represent the measuring points for chassis geometry measurement on the test object.

4. The resource coordinate system is centered in the corresponding wheel center and the points of the link RF ₁ and RF ₂ measured. The equipment must be moved individually for each wheel based on the previous coordinate system centering. This has the consequence that each measurement object gets assigned a different measurement history. Only in the ideal case (vehicle level 2 and resource level 3 are parallel), all measurement objects would be assigned the identical measurement history. 10 shows the plane E ₀ which the laser Verfahrenbene along the vehicle track plane 2 describes.

Nach dieser Konstruktion geht die Verbindungsstrecke RF₁RF₂ durch den Radmittelpunkt (Ursprung des Koordinatensystems $\left(\overrightarrow{e_1},\overrightarrow{e_2},\overrightarrow{e_3}\right)$

und liegt insbesondere in der Ebene span $\left(\overrightarrow{e_1},\overrightarrow{e_2}\right).$

Dabei wird die Ebene E₀ mit der Ebene E_xz des Betriebsmittels geschnitten. Diese Schnittgerade beschreibt den Verfahrweg (hier Laserverfahrweg) des Betriebsmittels, um eine korrekte Spurmessung durchzuführen. Analog dazu erfolgen die Ebenenschnitte mit den Radmittelpunkten HR, VL und VR. 11 zeigt die Ebene E₀ aus Sicht des Betriebsmittels sowie den Laserverfahrweg.The equipment (in this example a laser) now moves on the calculated plane ${\text{e}}_0=\text{HL}+\text{chip}\left(\overrightarrow{e_1}.\overrightarrow{e_2}\right),$

After this construction, the link goes RF ₁ RF ₂ through the wheel center (origin of the coordinate system $\left(\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}.\overrightarrow{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}.\overrightarrow{e_3}\right)$

and lies especially in the plane span $\left(\overrightarrow{e_1}.\overrightarrow{e_2}\right),$

This will be the level E ₀ with the plane E _xz cut the resource. This cutting line describes the travel (here laser travel) of the equipment to perform a correct track measurement. Similarly, the plane intersections take place with the Radmittelpunkten MR . VL and VR , 11 shows the plane E ₀ from the perspective of the equipment and the laser path.

gemessen werden. Durch die Parallelverschiebung entlang $\overrightarrow{e_3}$

wird die Messung korrekt durchgeführt und es existiert kein Sturzeinfluss.Other links above and below the Radmittelpunktes can by parallel displacement along $\overrightarrow{e_3}$

be measured. Through the parallel shift along $\overrightarrow{e_3}$

the measurement is performed correctly and there is no camber.

welche RF₁RF₂ enthält, und $\overrightarrow{e_1}$

ergibt. Durch Wahl des Koordinatensystems $\left(\overrightarrow{e_1},\overrightarrow{e_2},\overrightarrow{e_3}\right)$

und da $\overrightarrow{e_1}\text{ und }\overrightarrow{g}$

in span $\left(\overrightarrow{e_1},\overrightarrow{e_2}\right)$

liegen, kann der Spurwinkel φ wie folgt berechnet werden. $$\mathrm{\phi }=\sphericalangle \left(\overrightarrow{\text{g}},\overrightarrow{{\text{e}}_1}\right)=\text{arccos}\left(\langle \frac{\overrightarrow{{\text{RF}}_2}-\overrightarrow{{\text{RF}}_1}}{\left|\overrightarrow{{\text{RF}}_2}-\overrightarrow{{\text{RF}}_1}\right|}|\overrightarrow{{\text{e}}_1}\rangle \right)$$

5. The toe angle φ is now exactly the angle that is between the line $\overrightarrow{G}.$

Which RF ₁ RF ₂ contains, and $\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}$

results. By choice of the coordinate system $\left(\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}.\overrightarrow{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}.\overrightarrow{e_3}\right)$

and since $\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}\text{and}\overrightarrow{G}$

in span $\left(\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_1}.\overrightarrow{{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png"\; state="\{\{state\}\}">e</figure-callout>}}_2}\right)$

can lie, the toe angle φ calculated as follows. $$\mathrm{\phi }=\sphericalangle \left(\overrightarrow{\text{G}}.\overrightarrow{{\text{<figure-callout id="1" label="e" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">e</figure-callout>}}_1}\right)=\text{arccos}\left(<\frac{\overrightarrow{{\text{<figure-callout id="2" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_2}-\overrightarrow{{\text{<figure-callout id="1" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_1}}{\left|\overrightarrow{{\text{<figure-callout id="2" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_2}-\overrightarrow{{\text{<figure-callout id="1" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_1}\right|}|\overrightarrow{{\text{e}}_1}>\right)$$

Due to the general definition of the toe angle φ the following sign convention is to be used.

toe-in: $$-\text{sgn}<\overrightarrow{\text{R}}|\overrightarrow{{\text{e}}_2}><0\text{With}\overrightarrow{\text{R}}=\frac{\overrightarrow{{\text{<figure-callout id="2" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_2}-\overrightarrow{{\text{<figure-callout id="1" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_1}}{\left|\overrightarrow{{\text{<figure-callout id="2" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_2}-\overrightarrow{{\text{<figure-callout id="1" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_1}\right|}$$

toe: $$-\text{sgn}<\overrightarrow{\text{R}}|\overrightarrow{{\text{e}}_2}>>0\text{With}\overrightarrow{\text{R}}=\frac{\overrightarrow{{\text{<figure-callout id="2" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_2}-\overrightarrow{{\text{<figure-callout id="1" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_1}}{\left|\overrightarrow{{\text{<figure-callout id="2" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_2}-\overrightarrow{{\text{<figure-callout id="1" label="RF" filenames="DE102018008231A1\_0074.png,DE102018008231A1\_0075.png" state="{{state}}">RF</figure-callout>}}_1}\right|}$$

In summary results for the single track angle of a vehicle 1 following mathematical formula: $$\mathrm{\phi }=-\text{sgn}<\overrightarrow{\text{R}}|\overrightarrow{{\text{e}}_2}>*\text{arccos}\left(<\overrightarrow{\text{R}}|\overrightarrow{{\text{e}}_1}>\right)$$

Bei der Vermessung der Radmittelpunkte entsteht aufgrund von Messfehlern und Positionierungenauigkeiten der Automatisierungstechnik die Problematik, dass der Fahrwerksgeometriewinkel im Endeffekt nicht korrekt bestimmt wird. Daher wird eine Ebenenbetrachtung angewendet. Hierzu wird die Ebene E_HM definiert, welche aus dem Achsmittelpunkt HM, $\overrightarrow{{\text{e}}_1}\text{ und }\overrightarrow{{\text{e}}_3}$

besteht sowie die Ebene E_HR, die sich aus dem Radmittelpunkt HR, $\overrightarrow{e_3}\text{ und }\overrightarrow{g}$

zusammensetzt. 12 zeigt die Ebenen für die Berechnung des Spurwinkels φ.All of the aforementioned steps are necessary in order to ensure correct chassis geometry measurement in the event of vehicle track level tilt 2 to the resource level 3 perform. Analogous formulas apply to the camber angle with the corresponding cut line and the direction vector $\overrightarrow{e_3},$

When measuring the wheel centers, the problem arises due to measurement errors and positioning inaccuracies in the automation technology that the chassis geometry angle is ultimately not determined correctly. Therefore a plane view is applied. This is the level E _HM defined, which from the axle center HM . $\overrightarrow{{\text{e}}_1}\text{and}\overrightarrow{{\text{e}}_3}$

exists as well as the plane E _HR , which is made up of the wheel center MR . $\overrightarrow{e_3}\text{and}\overrightarrow{G}$

composed. 12 shows the planes for calculating the toe angle φ ,

$$\overrightarrow{{\text{n}}_{\text{HR}}}=\overrightarrow{{\text{e}}_{\text{3}}}\times \overrightarrow{\text{g}}$$

$$\mathrm{\phi }=\text{arccos}\left(\frac{\langle \overrightarrow{{\text{n}}_{\text{HM}}}|\overrightarrow{{\text{n}}_{\text{HR}}}\rangle }{\left|\overrightarrow{{\text{n}}_{\text{HM}}}\right|\cdot \left|\overrightarrow{{\text{n}}_{\text{HR}}}\right|}\right)$$

• $\overrightarrow{n_{HM}}$
  
  Normalenvektor der Fahrwerkssymmetrieebene
• $\overrightarrow{n_{HR}}$
  
  Normalenvektor der Raddrehebene 6 hinten rechts

The toe angle φ is now calculated using the normal vectors of the planes. $$\overrightarrow{{\text{n}}_{\text{HM}}}=\overrightarrow{{\text{e}}_{\text{3}}}\times \overrightarrow{{\text{e}}_1}$$

$$\overrightarrow{{\text{n}}_{\text{MR}}}=\overrightarrow{{\text{e}}_{\text{3}}}\times \overrightarrow{\text{G}}$$

$$\mathrm{\phi }=\text{arccos}\left(\frac{<\overrightarrow{{\text{n}}_{\text{HM}}}|\overrightarrow{{\text{n}}_{\text{MR}}}>}{\left|\overrightarrow{{\text{n}}_{\text{HM}}}\right|\cdot \left|\overrightarrow{{\text{n}}_{\text{MR}}}\right|}\right)$$

• $\overrightarrow{n_{HM}}$
  
  Normal vector of the chassis symmetry plane
• $\overrightarrow{n_{HR}}$
  
  Normal vector of Raddrehebene 6 back right

um 90° in der Raddrehebene 6 wird die Gerade $\overrightarrow{h}$

definiert. Die Ebene E_HR zur Sturzwinkelberechnung ergibt sich nun aus dem Radmittelpunkt HR, $\overrightarrow{e_1}\text{ und }\overrightarrow{h}.$

Die Berechnung des Sturzwinkels erfolgt analog zum Spurwinkel φ mit der neuen Ebene E_HR und der Ebene E_HM über die entsprechenden Normalenvektoren.By rotation of the cutting line $\overrightarrow{G}$

by 90 ° in the Raddrehebene 6 becomes the straight line $\overrightarrow{H}$

Are defined. The level E _HR for camber angle calculation now results from the wheel center MR . $\overrightarrow{e_1}\text{and}\overrightarrow{H},$

The calculation of the camber angle is analogous to the toe angle φ with the new level E _HR and the plane E _HM via the corresponding normal vectors.

LIST OF REFERENCE NUMBERS

1

vehicle

2

Vehicle orbital plane

3

Operating midplane

4

vehicle

5

journal

6

Raddrehebene

7

vertical plane

B

distance

C

distance

E ₀

level

e ₁

Suspension symmetry axis

e ₂

Hinterachssymmetrieachse

e ₃

vertical vector

Vorderachssymmetrieachse

F

direction of travel

G

line of intersection

g2

line of intersection

HL

Wheel center rear left

HM

Center of the rear axle

MR

Wheel center rear right

j

geometric driving axis

RF ₁

Measuring point for chassis geometry measurement

RF ₂

Measuring point for chassis geometry measurement

VL

Wheel center front left

VM

Center of the front axle

VR

Wheel center front right

X

vehicle longitudinal axis

δ

toe angle

φ

toe angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102017002891 A1 [0003]

Claims (3)

Method for measuring an axle geometry of a vehicle (1) having a front axle with two vehicle wheels (4) and a rear axle with two vehicle wheels (4), characterized in that positions of wheel centers of the vehicle wheels (4) are left rear (HL), rear right ( HR), front left (VL) and front right (VR) are measured with a resource, wherein a center of the rear axle (HM) corresponds to a sum of half of the positions rear left (HL) and rear right (HR), where a Center of the front axle (VM) corresponds to a sum of each half of the positions front left (VL) and front right (VR), where an Othonormalbasis $\left(\overrightarrow{e_1}.\overrightarrow{{\text{e}}_2}.\overrightarrow{{\text{e}}_3}\right)$

comprising a suspension axis of symmetry $\left(\overrightarrow{e_1}\right).$

a rear axle symmetry axis $\left(\overrightarrow{e_2}\right)$

and a vertical vector $\left(\overrightarrow{e_3}\right).$

is created with the help of the centers (HM, VM) and the Gram-Schmidt orthonormation method, wherein a coordinate system of the resource centered in the respective wheel center and measuring points (RF ₁ , RF ₂ ) of a link under wheel individual shifting of the equipment due to the centering of the coordinate system in one Plane (E ₀ ) through ${\text{e}}_{\text{0}}=\text{HL}+\text{chip}\left(\overrightarrow{e_1}.\overrightarrow{e_2}\right)$

is defined, measured, so that the link ( RF ₁ RF ₂ ) through the origin of the coordinate system $\left(\overrightarrow{e_1}.\overrightarrow{e_2}.\overrightarrow{e_3}\right)$

goes and in a plane $\left(\text{chip}\left(\overrightarrow{e_1}.\overrightarrow{e_2}\right)\right)$

where the plane (E ₀ ) is intersected with a plane (E _XZ ) of the resource and a resulting intersection line describes a travel of the resource, where the toe angle (φ) is the angle formed between the intersection line $\left(\overrightarrow{G}\right).$

which the link ( RF ₁ RF ₂ ) and the chassis symmetry axis $\left(\overrightarrow{e_1}\right)$

results. Method according to Claim 1 , characterized in that a plane view is applied, defining a plane (E _HM ), which consists of the center of the rear axle (HM), the suspension axis of symmetry $\left(\overrightarrow{e_1}\right)$

and the vertical vector $\left(\overrightarrow{e_3}\right)$

exists as well as a plane (E _HR ), which consists of the Radmittelpunkt (HR, HL), the vertical vector $\left(\overrightarrow{e_3}\right)$

and the cutting line $\left(\overrightarrow{G}\right)$

composed, wherein the toe angle (φ) over the normal vectors of the planes (E _HM , E _HR ) is calculated. Method according to Claim 2 , characterized in that by rotation of the cutting line $\left(\overrightarrow{G}\right)$

by 90 ° in the Raddrehebene (6) a straight line $\left(\overrightarrow{H}\right)$

is defined, wherein the plane (E _HR ) for camber angle calculation of the wheel center (HR, HL), the suspension axis of symmetry $\left(\overrightarrow{e_1}\right)$

and the straight line $\left(\overrightarrow{H}\right)$

results, wherein the calculation of the camber angle is analogous to the toe angle (φ) with the plane (E _HR ) and the plane (E _HM ) via the corresponding normal vectors.

Images