DE102022127340A1 - Method of determining a height of a center of gravity of a multi-axle truck - Google Patents

Abstract

The invention relates to a method for determining a height of a center of gravity (10) of a truck (14) having a plurality of axles (12), a horizontal weight measurement (20) being carried out, in which a weight is measured on each of the axles (12), while the truck (14) is standing on a horizontal surface, performing an inclined weight measurement (24) in which the weight on each of the axles (12) is measured while the truck (14) is standing on an inclined surface and the height of the center of gravity (10) from a comparison (26) of the weights measured on the axles (12) between horizontal weight measurement (20) and oblique weight measurement (24).

Description

The invention relates to a method for determining a height of a center of gravity of a truck having multiple axles according to the preamble of patent claim 1.

Trucks should be operated in a manner that minimizes the risk of rollover. A rollover can occur, for example, as a result of aggressive turning maneuvers or as a result of crosswinds. A truck's rollover stability as well as its general dynamic behavior are influenced by the location and in particular by the height of the center of gravity of the truck. If the truck includes a trailer and a towing vehicle, the position and height of the center of gravity of the trailer can be of particular importance.

There are systems such as stability control and/or rollover assist that depend on knowledge of the center of gravity to function properly. In addition, there are standards that specify a recommended maximum height of the center of gravity in order to keep the risk of a rollover low. In connection with highly automated trucks (for example SAE Level 4), it is desirable to determine the safety of a journey before it is put into operation.

the EP 2 787 330 A1 shows a method of weighing a load of a dump truck.

The object of the present invention is to provide a method by which the position of the center of gravity of a truck and in particular its height can be determined without, for example, placing sensors on the truck itself and/or having to carry out driving maneuvers with the truck and the Determination of the height of the center of gravity must be particularly precise.

This object is achieved according to the invention by the subject matter of the independent patent claim. Advantages and advantageous refinements and developments of the invention are the subject matter of the dependent patent claims, the description and the drawing.

In the method according to the invention, a height of a center of gravity or a center of gravity position of a truck having multiple axles is determined. In the method according to the invention, a horizontal weight measurement is carried out, in which a weight or a respective partial weight is measured on each of the axles of the truck while the truck is standing or resting on a horizontal surface. The horizontal weight measurement is carried out in particular with scales which are designed as vehicle scales and which can therefore be driven on by the truck for weighing or the truck is parked on the vehicle scales. Thus, the scale used in the method of the invention is not a component of the truck. The truck is designed in particular as a semi-trailer truck and thus comprises in particular a semi-trailer tractor or tractor unit and a semi-trailer or a trailer. The height of the center of gravity of the trailer is thus determined in particular in the method.

So that the height of the truck's center of gravity can now be determined in a particularly advantageous manner, without having to resort to sensors of the truck, for example, it is provided according to the invention that an oblique weight measurement is carried out. In this oblique weight measurement, the weight is measured on each of the axles while the truck is standing on an inclined surface and the height of the center of gravity is determined from a comparison of the weights measured on the axles and thus a weight distribution on the axles between horizontal weight measurement and oblique weight measurement .

In other words, a method for determining a center of gravity is presented, in which, in addition to measuring the weight on the axles on a horizontal surface, an oblique measurement is carried out, in which the truck is parked on an inclined plane, which in particular determines the position of the center of gravity or depending on the height of the center of gravity other weight distribution on the axles can be determined. By comparing the measurement results of the horizontal weight measurement and the oblique weight measurement, the height of the center of gravity or, in general, the center of gravity of the truck can be determined.

The invention is based on the finding that, particularly when driving a truck in a highly automated manner, several aspects need to be monitored, with the weight distribution within the trailer playing a particular role in the stability of the truck while driving. For example, large heights of the center of gravity can endanger the stability of the truck, which means negative consequences for the load, an infrastructure and/or people in the surroundings of the truck could. While the height of the tractor's center of gravity is usually known, this is not necessarily the case for a loaded semi-trailer or trailer.

It is known that equipping the semi-trailer with sensors could be helpful in estimating the height of the center of gravity. However, this would mean the purchase and maintenance and/or operation of a complex semi-trailer, which would, for example, involve significant costs. Furthermore, methods are known from the prior art, for example, in which a truck is shaken on a scale by means of a special shaking mechanism, which is required for the scale, in order to determine the height of the center of gravity via load oscillations. In addition, the height of the center of gravity can be estimated by, for example, having to drive the truck through previously defined driving maneuvers, with sensors also having to be attached to the semi-trailer in addition to the driving maneuvers. As a result, determining the center of gravity is particularly cumbersome and not free of risks. In addition, when driving on uneven ground, appropriate vibration detectors, where the unevenness of the ground is known, can be used to draw conclusions about the center of gravity in a complicated manner.

The present inventive method results in a highly automatic identification of the height of the center of gravity, in particular of the semitrailer or semitrailer, before the truck, designed in particular as a semitrailer, is operated and in particular without the need to mount additional sensors on the semitrailer.

In contrast, the method presented makes it possible to determine the height of the center of gravity particularly elegantly. A loaded truck, in particular an articulated lorry, is examined, the load and/or the distribution of which within the trailer are unknown. However, the weight of the truck is known and thus also the position of the center of gravity of the tractor or the unloaded truck.

The determination of the height of the center of gravity of the truck, or in particular its trailer, is essentially carried out in two main steps: In the first step, the truck is placed on a horizontal surface on which the weight on each axle can be measured. In the second step, the truck is placed on an inclined surface of known inclination, on which the weight on each axle can be measured. In addition, when the truck is designed to have a trailer and a tractor, it is not the trailer that is braked to hold position, but the tractor. By combining the information about the weights on the axles of the two steps and a number of known parameters of the truck, the height of the center of gravity can be determined, in particular with the help of force equations and/or moment equations. A third step can also be added for validation purposes. In this step, the truck is on an inclined surface with a different angle of inclination. Again, the weight on each axis can be measured analogously to the first oblique weight measurement.

In an advantageous embodiment of the invention, the trailer or semi-trailer of the truck is not braked and only the tractor or semi-trailer of the truck is braked, with the tractor being above the trailer or parked during the oblique weight measurement.

In a further advantageous embodiment of the invention, the height of the center of gravity is determined by equations for the force balance and/or moment balance using a number of known parameters, for example the weight distribution of the unloaded truck.

In a further advantageous embodiment of the invention, the oblique weight measurement is repeated with a different angle of inclination and the determination of the height of the center of gravity is thus checked.

Further advantages, features and details of the invention result from the following description of a preferred exemplary embodiment and from the drawing. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown alone in the single figure(s) can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the invention.

• 1 schematisches Diagramm eines Verfahrens zum Bestimmen einer Höhe eines Schwerpunkts eines Lastkraftwagens; und
• 2 schematische Seitenansicht des Lastkraftwagens bei einer schrägen Gewichtsmessung des Verfahrens gemäß 1.

It shows:

• 1 schematic diagram of a method for determining a height of a center of gravity of a truck; and
• 2 schematic side view of the truck in an oblique weight measurement according to the method 1 .

1 shows a schematic view of a method for determining a height of a center of gravity 10 of a truck 14 having a plurality of axles 12, the truck 14 being designed in particular as a semitrailer and comprising a semitrailer or trailer 16 and a semitrailer tractor or tractor 18. In the method for determining the height of the center of gravity 10, a horizontal weight measurement 20 is performed in which a weight is measured on each of the axles 12 while the truck 14 is standing on a horizontal surface or plane. The weight is measured in particular by means of a vehicle scale 22. In order to be able to determine the height of the center of gravity 10 in a particularly advantageous manner, an inclined weight measurement 24 is also carried out, in which the weight is measured on each of the axles 12 while the truck 14 is standing on an inclined surface and the height of the center of gravity 10 is determined from a comparison 26 of the weight distribution or the weights measured on the axles 12 between the horizontal weight measurement 20 and the oblique weight measurement 24 .

Advantageously, the trailer 16 of the truck 14 is unbraked during the inclined weight measurement 24 on the inclined plane or the inclined ground, whereas the tractor 18 is braked.

Furthermore, the height of the center of gravity 10 is determined by a number of known parameters 30 by means of equations for a force balance and/or a moment balance. In order to determine the height of the center of gravity 10 particularly precisely or to verify the height determination, the oblique weight measurement 24 can be repeated with a different angle of inclination θ in order to check the calculation or the determination. The right box of the 1 shows the result 30 of the height determination.

2 shows the truck 14 in a schematic view during the oblique weight measurement 24, with the parameters used for determining the height being drawn in. The calculation or determination of the height of the center of gravity 10 can be described using the example shown, with the height of the center of gravity 10 of the trailer 16 being determined from the information available.

These include as in 1 shown the results of the horizontal weight measurement 20, parameters 28 and the results of the oblique weight measurement 24, which lead to the result 30 through the comparison 26.

Specifically, three equations can be used to determine the weight of the trailer 16 and the fore/aft location of the trailer's 16 center of gravity 10 .

Thus, in the horizontal position or during the horizontal weight measurement 20, a balance of forces for the tractor 18, a balance of forces for the trailer 16 and a moment balance for the trailer 16 or its rear axle 12 can be met.

Where the force balance of the tractor applies: $${\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{12.\mathrm{e.g}}+m_{1}G=f_{1R.\mathrm{e.g}}+f_{1f.\mathrm{e.g}}.$$

For the forces of the trailer 16 apply: $${\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}\mathrm{e.g}}+f_{2R,\mathrm{e.g}}=m_{2}G.$$

The following applies to the moments of the trailer, in particular on its rear axle 12: $$x_{12}{\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}\mathrm{e.g}}=x_{22}{m}_{2}G.$$

From this it can be deduced: $${\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}\mathrm{e.g}}{x}_{22}{m}_{2}G.$$

The height of the center of gravity 10 of the trailer 16 is determined from the information from the second step of the method, ie the oblique weight measurement 24 and some of the values just determined in step 1 and the parameters 28 . For this purpose, the in 2 The forces and equilibrium equations drawn in for the oblique weight measurement 24 are used analogously to the calculations just carried out for the horizontal weight measurement 20.

Of the three equations, the first equation corresponds to the vertical force balance equation for tractor 18. The second equation corresponds to the longitudinal force balance equation for trailer 16. The third equation corresponds to the rear wheel and rear wheel moment balance equation, respectively the rear axle 12 of the trailer 16.

The balance of forces for the tractor is given by: $${\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}\mathrm{e.g}}+m_{1}GcOs\theta =f_{1R,\mathrm{e.g}}+f_{1f,\mathrm{e.g}}$$

The balance of forces on the trailer 16 in the longitudinal direction is given by: $${\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}x}=m_{2}Gsin\theta .$$

The balance of moments on the trailer 16 on the rear axle 12 results from: $$x_{22}{m}_{2}GcOs\theta +H_{21}{\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}x}=H_{COG2}{m}_{2}Gsin\theta +x_{21}{\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}\mathrm{e.g}}.$$

This results in: $${\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}\mathrm{e.g}},{\mathrm{<figure-callout\; id="12"\; label="f"\; filenames="DE102022127340A1\_0009.png,DE102022127340A1\_0010.png"\; state="\{\{state\}\}">f</figure-callout>}}_{\mathrm{12,}x}{H}_{COG2.}$$

The method presented here makes it possible, for example, to dispense with expensive sensors that have to be attached to the trailer 16 in order to determine the height of the center of gravity 10 . The method presented here requires only an external vehicle scale 22, which can be designed in particular as a standard scale that can be present, for example, in turnstiles at which trucks 14 drive. The trucks 14 are loaded and unloaded in the turnstiles, for example, for operation. Another advantage is that no movement data recorded while driving is required to determine the height of the center of gravity 10 . As a result, the method can be included in the inspection routine that is carried out anyway before the truck 14 is operated, as a result of which the operational readiness of the truck 14 can already be advantageously ensured.

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

• EP 2787330 A1 [0004]

Claims (4)

A method for determining a height of a center of gravity (10) of a truck (14) having multiple axles (12), wherein a horizontal weight measurement (20) is performed, in which a weight is measured on each of the axles (12) while the truck ( 14) standing on a horizontal surface, characterized in that an inclined weight measurement (24) is carried out, in which the weight on each of the axles (12) is measured while the truck (14) is standing on an inclined surface and the height of the Center of gravity (10) from a comparison (26) of the weights measured on the axes (12) between horizontal weight measurement (20) and oblique weight measurement (24). procedure after claim 1 , characterized in that a trailer (16) of the truck (12) is not braked and only one tractor (18) is braked, which is above the trailer (16) during the oblique weight measurement (24). procedure after claim 1 or 2 , characterized in that with a series of known parameters (30) of the truck (12), the height of the center of gravity (10) is determined by equations for a force balance and/or a moment balance. Method according to one of the preceding claims, characterized in that the oblique weight measurement (24) is repeated with a different angle of inclination and the determination of the height of the center of gravity (10) is thus checked.

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