DE102017202178A1 - Determining the center of gravity height of a motor vehicle - Google Patents

Abstract

A method (500) for determining a center of gravity height (h) of a motor vehicle (100) comprises steps of changing a ride height of a wheel (105) of the motor vehicle (100) by means of an active chassis (120); determining (540) a resulting ride on a wheel (105); and determining (545) the center of gravity height (h) based on the detected ride height.

Description

The present invention relates to the determination of the center of gravity height of a motor vehicle. The invention also relates to the control of a motor vehicle, a control device and a motor vehicle equipped therewith.

A control system for a motor vehicle considers vehicle parameters to control, for example, the longitudinal or lateral control of the motor vehicle based on dynamic parameters such as a turning radius or a speed. Some vehicle parameters are always the same, such as a wheelbase or track, while other parameters such as mass or the location of a center of gravity may be subject to certain changes.

From the DE 100 53 605 B4 relates to a system and method for determining the center of gravity height of a motor vehicle by means of a roll model based on dynamic shear forces.

Dynamic lateral forces can act on the motor vehicle by many different causes, so that such a provision can be inaccurate. For a safe and comfortable ride, it is also often desirable to determine the center of gravity height before the start of a journey. This is not possible if lateral acceleration is required to determine the center of gravity.

An object of the invention is to provide an improved technique for determining the center of gravity height of a motor vehicle. In particular, an object is to determine the center of gravity without determining a lateral acceleration.

According to one aspect of the invention, a method for determining a center of gravity height of a motor vehicle is proposed, which comprises the steps of changing a ride height of a wheel of the motor vehicle by means of an active chassis; determining a resulting ride height on a wheel; and determining the center of gravity height based on the detected altitude. By changing the ride height relative loads of the individual wheels can be changed. The resulting ride height can be determined on the bike where the ride height was changed or on another bike.

The ride height is a distance between a wheel and the sprung mass of the motor vehicle and can be determined, for example, as a distance between a wheel axle and a body of the motor vehicle when said points are substantially vertically aligned with each other. The determination is based on the knowledge that a change in ride heights of the wheels of the motor vehicle due to an increase or decrease of one of the wheels is greater, the higher the center of gravity. Due to the amounts of the wheel heights before and after the activation of the active chassis, the center of gravity height can be determined.

By doing so, the center of gravity height can be determined without having to detect lateral accelerations, so that the vehicle does not have to be in motion to determine the center of gravity. The properties and possibilities of an active chassis can be advantageously exploited in the method. A horizontal position of the center of gravity, in particular in the longitudinal or transverse direction, can be determined by measuring the wheel contact forces, so that the position of the center of gravity can be determined two- or three-dimensionally. The wheel contact forces can be statically determined in particular on the basis of a spring stiffness of a chassis and a deflection or a ride on a wheel.

As active suspension is understood in the context of this application, in particular a chassis that allows active height adjustment of a single wheel. In a first variant, an actuator for height adjustment is integrated with a spring element, which is mounted between the wheel and the body. In this case, it is preferable to consider ride height of other wheels to determine the reaction of the landing gear. The reaction preferably comprises a change of the ride height at one or more other wheels of the motor vehicle.

The wheels on which the change in the height is determined are preferably associated with a common axis. In a motor vehicle with a front wheel axle and a rear wheel axle, for example, the ride heights of one or both wheels of the rear wheel axle can be changed and the change in the ride heights on one or both wheels of the front wheel axle can be determined and evaluated. Conversely, the ride height on the front wheel axle can also be changed and the ride height on the rear wheel axle can be viewed.

In a second variant, the actuator and the spring element are connected in series. The adjustment of the actuator can then cause a change in the ride height of the associated wheel, which can be determined due to a spring-Radhub ratio. In this case, for the determination the reaction of the landing gear ride height of all wheels are considered.

The reaction may include a change in the altitude local height change of the motor vehicle, in particular a mean change in height of a predetermined axis of the motor vehicle. For this purpose, the driving advantageously comprises a common driving of the predetermined axis of the motor vehicle associated actuators of the active chassis. The predetermined axis may be a front wheel axle or a rear wheel axle.

• eines Raddurchmessers wenigstens eines Rades des Kraftfahrzeugs;
• einer Radlast wenigstens eines Rades des Kraftfahrzeugs;
• einer gesamten gefederten Masse des Kraftfahrzeugs;
• eines Achsabstands des Kraftfahrzeugs;
• einer horizontalen Schwerpunktlage des Kraftfahrzeugs;
• eine ungefederte Masse wenigstens eines Rades des Kraftfahrzeugs.

Preferably, the determination of the center of gravity takes place taking into account at least one of the following parameters:

• a wheel diameter of at least one wheel of the motor vehicle;
• a wheel load of at least one wheel of the motor vehicle;
• an entire sprung mass of the motor vehicle;
• a center distance of the motor vehicle;
• a horizontal center of gravity of the motor vehicle;
• an unsprung mass of at least one wheel of the motor vehicle.

ausgedrückt werden kann, wobei h die Schwerpunktshöhe ist, R ein Raddurchmesser eines Rades ist, F_Ges eine Summe der Radlasten der gefederten Masse aller Räder ist, F_HA eine Summe der Radlasten der gefederten Masse der Räder an der Hinterachse ist, m eine ungefederte Masse des Kraftfahrzeugs ist, g die Erdbeschleunigung ist, I ein Achsabstand des Kraftfahrzeugs ist, I1 ein Abstand des Schwerpunkts von der Vorderradachse ist, und H eine Höhenänderung aufgrund Ansteuerung des Fahrwerks.The wheel load of at least one wheel may also include an axle load or a common load of the wheels of a side of the vehicle added from the individual wheel loads of the associated wheels. The above parameters may be linked to the center of gravity height, for example, by a relationship, in particular by $H=R+\left(\frac{F_{Ges}-F_{HA}}{mG}l-l_1\right)\cdot \text{cot}\left(\text{arctan}\frac{H}{l}\right)$

can be expressed, where h is the center of gravity height, R is a wheel diameter of a wheel, F _{Ges is} a sum of the sprung mass wheel loads of all wheels, F _{HA is} a sum of the sprung mass wheel loadings on the rear axle, m unsprung mass of the motor vehicle, g is the gravitational acceleration, I is a wheelbase of the motor vehicle, I1 is a distance of the center of gravity from the front wheel axle, and H is a height change due to actuation of the chassis.

Preferably, the method is carried out at standstill of the motor vehicle. In particular, the method can be carried out after stopping or before starting the motor vehicle. In a further embodiment, the method can also be carried out at a stopover of the motor vehicle, for example a stop at a traffic light. As a result, for example, a change in the height of the center of gravity due to a change in the load while driving, such as a changed content of a fuel tank or by a movement of a person on board the motor vehicle, are taken into account.

• - eine Zündung des Kraftfahrzeugs wurde betätigt;
• - das Fahrzeug befindet sich im Stillstand;
• - eine Tür des Kraftfahrzeugs wurde geöffnet und/oder geschlossen;
• - eine Änderung in einer Beladung und/oder Sitzbelegung des Kraftfahrzeugs wurde festgestellt;
• - ein Insassenrückhaltesystem des Kraftfahrzeugs wurde aktiviert und/oder deaktiviert;
• - das Kraftfahrzeug befindet sich auf einem horizontalen, weiter bevorzugt ebenen Untergrund.

In embodiments, the steps of driving the landing gear, determining the response to the driving, and determining the center of gravity height are performed based on the response only when at least one triggering condition is met, wherein the triggering condition is selected from the group consisting of:

• - An ignition of the motor vehicle was operated;
• - the vehicle is at a standstill;
• - A door of the motor vehicle was opened and / or closed;
• - a change in a load and / or seat occupancy of the motor vehicle has been detected;
• - An occupant restraint system of the motor vehicle has been activated and / or deactivated;
• - The motor vehicle is located on a horizontal, more preferably even ground.

This makes it possible to limit the determination of the center of gravity to relevant events, which experience has shown can be associated with a change in the center of gravity. Alternatively and / or additionally, the determination of the center of gravity position can also be repeated at predetermined time intervals.

According to a further aspect of the invention, a method is proposed for controlling a motor vehicle using an active chassis, wherein an algorithm used for controlling the motor vehicle takes into account a center of gravity height of the motor vehicle, wherein the center of gravity height is determined by means of a process comprising the steps of: driving the active chassis; Determining a response of the active landing gear; and determining the center of gravity height based on the detected response. In embodiments, the process includes the method of determining the centroid height described above.

In further embodiments, the method includes control for automated, semi-automated or autonomous driving. In Europe and the United States (including SAE J3016), the classification of autonomous driving is usually made in six stages, from the third stage, an at least temporarily driver-independent control of the motor vehicle is possible. In the fifth and highest level, the driving operation can be carried out completely without the presence of a person on board the motor vehicle. To improve autonomous control, the particular center of gravity height can be taken into account, so that the behavior of the moving motor vehicle is more accurately predictable.

According to a further aspect of the invention, a device for controlling a motor vehicle is proposed, the device comprising: an output interface for outputting a first signal to an active chassis of the motor vehicle; a first input interface for receiving a second signal indicative of a response of the active landing gear; a processing unit coupled to the output interface and the first input interface for generating the first signal to drive the active chassis, for providing the first signal to the first interface, and determining a center of gravity height of the motor vehicle based on the received second signal. In embodiments, the processing unit is configured to perform one of the methods described above.

According to a further aspect of the invention is a motor vehicle with a body and at least one wheel and a control device for controlling motor vehicle functions, wherein the control device is designed as described above.

The control device is preferably configured to carry out the method described above in whole or in part. For this purpose, the control device may comprise a programmable microcomputer or microcontroller and the method may be in the form of a computer program product with program code means. The computer program product may be executed on a processing device of the device or stored on a computer-readable medium. Advantages or features of the method can be transferred to the control device and vice versa.

• 1 eine schematische Seitenansicht eines Kraftfahrzeugs;
• 2 eine schematische Draufsicht auf das Kraftfahrzeug von 1;
• 3 eine schematische Vorderansicht des Kraftfahrzeugs von 1;
• 4 eine schematische Seitenansicht des Kraftfahrzeugs entsprechend 1 zur Veranschaulichung eines Verfahrens zur Ermittlung einer Schwerpunktshöhe des Kraftfahrzeugs;
• 5 ein Ablaufdiagramm des Verfahrens zur Ermittlung einer Schwerpunktshöhe des Kraftfahrzeugs; und
• 6 ein Ablaufdiagramm eines Verfahrens zum Steuern eines Kraftfahrzeugs darstellt.

The invention will now be described in more detail with reference to the attached figures, in which:

• 1 a schematic side view of a motor vehicle;
• 2 a schematic plan view of the motor vehicle of 1 ;
• 3 a schematic front view of the motor vehicle of 1 ;
• 4 a schematic side view of the motor vehicle accordingly 1 to illustrate a method for determining a center of gravity height of the motor vehicle;
• 5 a flowchart of the method for determining a center of gravity height of the motor vehicle; and
• 6 a flowchart of a method for controlling a motor vehicle represents.

A motor vehicle 100 is with essential components and geometric relationships in 1 to 3 shown schematically. It shows 1 a schematic side view of the motor vehicle 100 from the left, shows 2 a schematic plan view of the motor vehicle 100 and shows 3 a schematic front view of the motor vehicle 100 , The directions of sight in the 2 and 3 are taken in 1 indicated by arrows "II" and "III". The car 100 preferably comprises a passenger vehicle, more preferably for use in city traffic.

In a preferred embodiment, the motor vehicle 100 adapted to be controlled in the longitudinal and / or transverse direction by means of an automatic control device. The control device can in particular for fully automatic or autonomous control of the motor vehicle 100 be furnished. To correctly predict a reaction of the motor vehicle 100 to a control intervention, the control device is dependent on certain driving and vehicle parameters, one of which is the position of a center of gravity of the motor vehicle 100 can be.

The car 100 indicates as shown in 1 several wheels 105 and a body 110 on. As in 2 shown, the motor vehicle 100 in this embodiment, four wheels 105 of which a left front wheel 105 (VR) and a right front wheel 105 (VL) of a front wheel axle 205 and of which a left rear wheel 105 (HL) and a right rear wheel 105 (HR) of a rear wheel axle 210 assigned. The front wheel axle 205 and the rear wheel axle 210 have an axial distance I, and the left front wheel 105 (VR) and the right front wheel 105 (VL) have a track width b on. A track width on the rear axle 210 is usually the same size. A steering wheel 215 is exemplified left front in the vehicle interior, which defines the usual position of a driver in right-hand traffic.

The body 110 has a sprung mass m on that in a focal point 115 is concentrated (see also 1 ). The sprung mass m includes the part of the total mass of the motor vehicle 100 that by a landing gear 120 from the wheels 105 is elastically decoupled. The unsprung mass includes the masses of the wheels 105 and the landing gear 120 , Depending on how many people, pieces of luggage and / or other loads where in the vehicle 100 may be the location of the center of gravity 115 of the motor vehicle 100 to change.

A total wheel load of the sprung mass m is $${\text{F}}_{\text{Ges}}=\text{m}*\text{G}$$

$${\text{F}}_{\text{HA}}={\text{F}}_{\text{HL}}+{\text{F}}_{\text{HR}}$$

zusammengefasst werden. Ferner können in Querrichtung des Kraftfahrzeugs 100 die Radlasten der linken Räder 105(VL), 105(HL) als linksseitige Radlast F_L und die Radlasten der rechten Räder 105(VR), 105(HR) als rechtsseitige Radlast F_R mit $${\text{F}}_{\text{L}}={\text{F}}_{\text{VL}}+{\text{F}}_{\text{HL}},$$

$${\text{F}}_{\text{R}}={\text{F}}_{\text{VR}}+{\text{F}}_{\text{HR}}$$

zusammengefasst werden. Es gilt somit und $${\text{F}}_{\text{Ges}}={\text{F}}_{\text{VA}}+{\text{F}}_{\text{HA}}$$

$${\text{F}}_{\text{Ges}}={\text{F}}_{\text{L}}+{\text{F}}_{\text{R}}.$$

und insbesondere auch $${\text{F}}_{\text{Ges}}={\text{F}}_{\text{VL}}+{\text{F}}_{\text{VR}}+{\text{F}}_{\text{HL}}+{\text{F}}_{\text{HR}}.$$

It is first assumed that the motor vehicle 100 located on a level surface. The location of the center of gravity 115 can be in a three-dimensional, on the bodywork of the motor vehicle 100 fixed cartesian coordinate system in the longitudinal, transverse and vertical directions. A horizontal position of the center of gravity 115 is here by a distance I ₁ from the front wheel axle 205 and a distance b ₁ from the right front wheel 105 (VR) defines a vertical center of gravity position H as the distance of the center of gravity 115 from a footprint 130 the wheels 105 of the motor vehicle 100 , The total wheel load F _{Ges is} distributed over the four wheels 105 as single wheel loads F _VL the left front wheel 105 (VL), F _VR the right front wheel 105 (VR), F _HL of the left rear wheel 105 (HL), F _{HR of} the right rear wheel 105 (HR) as a function of the horizontal center of gravity position l ₁ , b ₁ . In this case, in the longitudinal direction of the motor vehicle 100 the wheel loads of the front wheels as Vorderradachslast F _VA and the wheel loads of the rear wheels as Hinterradachslast F _HA With $${\text{F}}_{\text{VA}}={\text{F}}_{\text{VL}}+{\text{F}}_{\text{VR}}.$$

$${\text{F}}_{\text{HA}}={\text{F}}_{\text{HL}}+{\text{F}}_{\text{MR}}$$

be summarized. Further, in the transverse direction of the motor vehicle 100 the wheel loads of the left wheels 105 (VL), 105 (HL) as left-side wheel load F _L and the wheel loads of the right wheels 105 (VR), 105 (HR) as the right-side wheel load F _R With $${\text{F}}_{\text{L}}={\text{F}}_{\text{VL}}+{\text{F}}_{\text{HL}}.$$

$${\text{F}}_{\text{R}}={\text{F}}_{\text{VR}}+{\text{F}}_{\text{MR}}$$

be summarized. It therefore applies and $${\text{F}}_{\text{Ges}}={\text{F}}_{\text{VA}}+{\text{F}}_{\text{HA}}$$

$${\text{F}}_{\text{Ges}}={\text{F}}_{\text{L}}+{\text{F}}_{\text{R}},$$

and especially $${\text{F}}_{\text{Ges}}={\text{F}}_{\text{VL}}+{\text{F}}_{\text{VR}}+{\text{F}}_{\text{HL}}+{\text{F}}_{\text{MR}},$$

bzw. $${\text{b}}_1={\text{FL/F}}_{\text{Ges}}*\text{b}$$

ausgedrückt werden.This allows the horizontal center of gravity position $${\text{I}}_1={\text{F}}_{\text{HA}}{\text{/ F}}_{\text{Ges}}*\text{I}$$

respectively. $${\text{b}}_1={\text{FL / F}}_{\text{Ges}}*\text{b}$$

be expressed.

These values can already be achieved with a passive chassis 120 determine if this is equipped with a displacement sensor or the like. In particular, preference is given to suspension travel on the individual wheels 105 to be determined on the basis of a spring stiffness of the chassis 120 or a spring stiffness of a spring on the respective wheel 105 to be able to conclude on a wheel load. To determine the vertical center of gravity (center of gravity) H However, a simple distance measurement on the springs is not enough.

With an active chassis 120 can suspension or damping parameters of the chassis 120 to be changed. Will be the active suspension 120 of the motor vehicle 100, so may a reaction of the chassis 120 usually by means of a measuring system of the chassis 120 be recorded. Such a reaction can be used to determine the center of gravity H of the center of gravity 115 be exploited, as will be explained in more detail below.

As in 1 shown is the bodywork 110 is about the landing gear 120 with the wheels 105 connected. The chassis 120 is an active chassis and has actuators or actuators 125 on. With the active chassis 120 deliver the actuators 125 all or part of the forces that are otherwise generated passively by springs or dampers. The actuators can do this 125 be controlled by a controller so that roll and pitching movements of the body 110 be reduced as possible during cornering or braking or acceleration. A rolling motion corresponds to a tendency of the sprung mass m of the motor vehicle 100 about the longitudinal axis, a pitching motion of an inclination about the transverse axis, the wheels 105 usually keep ground contact. For the control of roll or Nickbeweung can be an actuator 125 on a damping of the vertical movement of a wheel 105 act on the sprung mass in compression and / or rebound. In addition, the distance of the motor vehicle 100 over a roadway 130 be controlled as possible wheel individually. The actors 125 may in particular act hydraulically, pneumatically or mechanically. Without limitation of generality, the chassis 120 thus for every bike 105 an individually assigned actor 125 on. To simplify the illustration is in 1 but only one actor 125 shown.

Preferably, the active chassis comprises 120 a height measuring system for determining a distance between a wheel 105 and the body of the motor vehicle 100 , One through the active chassis 120 caused change in the ride height on a wheel can thus also be determined, such as a compression of a spring element of the chassis 120 by dynamic or static forces. Is one through the active chassis 120 amount of ride height on a wheel 105 known, so can a wheel load on a wheel 105 as a product of the remaining ride height with a spring stiffness of the chassis 120 be determined on this wheel 105. The wheel load can work the same way on a conventional suspension 120 be determined with height measuring system.

In one embodiment, the actuator is 125 in series with a spring or other elastic element between the wheel 105 and the sprung mass m appropriate. In this case, a spring-wheel stroke ratio can be taken into account, which indicates how the ride height or wheel stroke of a wheel 105 depending on an adjustment of the actuator 125 changed. This allows the ride height from a control or a selected position of the actuator 125 be determined.

If at different times strongly different tires or brakes on the axles 205 . 210 being driven, such as on a sports car, for example, the unsprung mass of each wheel is preferred 105 determined and stored. To determine the total mass of the motor vehicle 100 become unsprung masses m , in particular based on the ride height of the wheels 105 can be determined, preferably the unsprung masses of the wheels 105 added.

4 shows in a schematic representation, the view of 1 corresponds to the motor vehicle 100 with a control device 400 , The control device 400 has a processing unit 405 , an optional storage unit 410 , an output interface 415 , a first input interface 420, and several optional second input interfaces 430 on. The output interface 415 is with the actors 125 active chassis 120 connected to control signals to the actuators 125 issue. The first input interface 420 is with displacement sensors 425 which a deflection of respective suspensions of the wheels 105 capture, connected and set up by the displacement sensors 425 received sensor signals and to the processing unit 405 pass.

The implementation of the determination is generally possible when the motor vehicle 100 on a flat footprint 130 is at a standstill and prefers no person on board the motor vehicle 100 located. Whether the motor vehicle 100 in motion, based on a speed signal or a rate of rotation of one of the wheels 105 be determined. Whether the motor vehicle 100 is on a flat footprint can be determined based on the scanned wheel heights, a signal of a gyroscope or an acceleration sensor or external information.

In one embodiment, the determination of the center of gravity height is performed only when there is no person on board the motor vehicle 100 located. Thus, a measurement inaccuracy can be prevented by a movement of the person during the measurement. In addition, it can be avoided that the measuring process for the person takes place unexpectedly and is perceived by her as unpleasant. A second input interface may be used to determine whether a person is aboard the motor vehicle 100 430 be provided, which preferably with one or more sensors on the motor vehicle 100 connected is. For example, the sensors may include a retention sensor 435 sensing a state of a restraint system, particularly a buckle of an occupant restraint belt, a door sensor 440 , which is an opening and / or closing state of a door of the motor vehicle 100 detects, an interior monitoring sensor, which in normal optical, infrared optical, ultrasound-based or other way, the interior of the body 110 monitored to detect a occupancy and / or loading condition of the motor vehicle 100 or changes thereof, a seat occupancy sensor 450 , which is an occupancy of a seat (not shown in detail) of the motor vehicle 100 detects an ignition condition sensor 455 , a speed sensor and / or the like. On the basis of sensor signals of the second input interface 430 can be done by the control device 400 be determined at least with a predetermined probability that no person on board the motor vehicle 100 located.

The optional storage unit 410 is preferably configured to temporarily and / or permanently store immutable and / or variable parameters which are relevant for the motor vehicle control. In particular, in the storage unit 410 Constants like the gravitational acceleration G or basically changeable, but during a ride in general unchanged vehicle parameters such as wheelbase l , Track width b , Wheel diameter R , unsprung wheel masses or other parameters permanently stored. For example, when changing a wheel or changing the chassis 120 may be a corresponding motor vehicle parameter in the memory unit 410 to be updated. The control device 400 is preferably adapted to a control method for determining a center of gravity H of the motor vehicle 100 by driving the active chassis 120 , Determining a response of the active landing gear 120 and determining the center of gravity H on the basis of the determined reaction, as will be described in detail below. The determined center of gravity coordinates can be used to control the motor vehicle 100 be used. This control can be done automatically by means of one on the control device 400 or another control device on board the motor vehicle 100 ongoing procedures are carried out.

5 shows a flowchart of a method 500 for determining a center of gravity height H of the motor vehicle 100 , The procedure 500 may be arranged to be at least partially on the control device 400 to be executed. The process performed below is to be understood as exemplary; Modifications, in particular with regard to the sequence of steps or the execution of optional steps, can be made by a person skilled in the art with reference to the description 5 to think for yourself.

• - eine Zündung des Kraftfahrzeugs 100 wurde betätigt, bestimmbar auf der Basis eines Signals von dem Zündsensor 455;
• - das Fahrzeug befindet sich im Stillstand, bestimmbar auf der Basis eines Signals von dem Geschwindigkeitssensor 460;
• - eine Tür des Kraftfahrzeugs 100 wurde geöffnet und/oder geschlossen, bestimmbar auf der Basis eines Signals von dem Türsensor 440;
• - eine Änderung in einer Beladung und/oder Sitzbelegung des Kraftfahrzeugs 100 wurde festgestellt, bestimmbar auf der Basis eines Signals von dem Innenraumüberwachungssensor 445 und/oder dem Sitzbelegungssensor 450;
• - ein Insassenrückhaltesystem des Kraftfahrzeugs 100 wurde aktiviert und/oder deaktiviert, bestimmbar auf der Grundlage eines Signals von dem Gurtsensor 435.

In an optional first step 505 be signals from the second input interfaces 430 read. In a subsequent, optionally optional step 510, based on the signals from the second input interfaces 430 judges whether or not there is a condition for performing a center of gravity determination. For example, but not only, a condition can be one of the following conditions:

• - An ignition of the motor vehicle 100 was actuated, determinable based on a signal from the ignition sensor 455 ;
• - The vehicle is at a standstill, determinable based on a signal from the speed sensor 460 ;
• - a door of the motor vehicle 100 has been opened and / or closed, determinable on the basis of a signal from the door sensor 440 ;
• - A change in a load and / or seat occupancy of the motor vehicle 100 has been determined determinable based on a signal from the indoor monitoring sensor 445 and / or the seat occupancy sensor 450 ;
• - An occupant restraint system of the motor vehicle 100 has been activated and / or deactivated, determinable on the basis of a signal from the belt sensor 435.

If the assessment in step 510 the process can be negative 500 end up. Otherwise, the processing preferably proceeds to another optional step 515 in which one in the storage unit 410 stored base parameter can be read in, for the further determination of the center of gravity H is required. The step 510 may also be at a later stage of the procedure 500 be performed.

In one step 520 be signals from the first input interface 420 read. The signals at the first input interface 420 correspond to sensor signals due to a deflection of suspensions on the wheels 105 indicate. Because the wheels 105 by means of the chassis 120 elastic with the sprung mass of the motor vehicle 100 are connected, the deflections point to wheel loads on the individual wheels 105 out.

In one step 525 can be a horizontal center of gravity l1 . b1 in the longitudinal and / or transverse direction of the motor vehicle 100 based on the at the first input interface 420 received signals are determined. The determination can be carried out by means of functions or by means of a value table or a characteristic diagram, which map, for example, the equations 9 and 10 mentioned above. The determination may be a determination of the current wheel loads F _VL . F _VR . F _HL . F _HR based on respective deflections of suspension of the wheels 105 include that made at the first input interface 420 received signals and in step 515 read base parameter read in terms of, for example, a spring constant or a zero point of the respective suspension.

In one step 530 become command signals to control actuators 125 active chassis 120 generated and via the output interface 415 output to the actuators 125. This step corresponds to a driving of the active chassis 120 such that the motor vehicle 100 is tilted, preferably forward or backward. In the present example is a positive change in altitude H at the front wheel axle 205 gone out, the motor vehicle 100 is tilted backwards as in 4 is shown. To the inclination of the motor vehicle 100 to effect at least one actor 125 driven to increase or decrease the ride height of a wheel 105. Preference is given to actuators 125 of wheels 105 of the same wheel axle 205 . 210 driven in the same direction.

In one step 535 are again preferred signals from the first input interface 420 read. The signals at the first input interface 420 correspond to sensor signals indicative of a deflection of suspensions on the wheels 105 suggest, especially wheels 105 , their associated actuators 125 in step 530 were not driven. The signals can be on ride height at the wheels 105 indicate or prefer amounts of changes in ride height in response to activation of the active landing gear in step 530 affect.

In one step 540 becomes a reaction of the active landing gear 120 to the control in step 530 determined. The determination corresponds to a calculation of the altitude change H at the front axle 205 from a difference between the ones in step 525 determined deflections and the now existing deflections or height levels, resulting from the in step 535 at the first input interface 420 received signals and optionally one in step 515 read base parameter read in terms of, for example, a spring constant and / or a zero point of the respective suspension.

bestimmt werden. In Gleichung 11 ist vereinfachend angenommen, dass die Raddurchmesser an allen vier Rädern 105 gleich sind. Bei unterschiedlicher Bereifung kann Gleichung 11 angepasst werden, um diese Einflüsse zu berücksichtigen. Die Bestimmung kann algorithmisch, mittels einer Wertetabelle oder eines Kennfeldes, welche die vorstehende Gleichung (11) oder eine andere geeignete, gegebenenfalls experimentell ermittelte Beziehung abbildet, durchgeführt werden.In one step 545 becomes the center of gravity H on the basis of the signals read in at the first input interface and optionally from the memory unit 410 read parameters. When the motor vehicle 100 through the active chassis 120 at one of the wheel axles 205 . 210 around the value H is raised, the height can H of the center of gravity 115 through the relationship $$H=R+\left(\frac{F_{Ges}-F_{HA}}{mG}l-l_1\right)\cdot \text{cot}\left(\text{arctan}\frac{H}{l}\right)$$

be determined. In equation 11, it is assumed for simplicity that the wheel diameter on all four wheels 105 are the same. For different tires, equation 11 can be adjusted to take these influences into account. The determination may be performed algorithmically, by means of a look-up table or map mapping equation (11) above or another suitable, possibly experimentally determined relationship.

After the step 545 can the procedure 500 or return to a parent process. The procedure 500 can also be run through multiple times to determine several center of gravity heights, which can then be averaged.

6 shows a flowchart of a method 600 for controlling the motor vehicle 100 , The procedure 600 may be set up, in whole or in part, on the control device 400 to be executed. The process performed below is to be understood as exemplary; Modifications, particularly with regard to the sequence of steps and the execution of optional steps, can be made by a person skilled in the art with reference to the description 6 to think for yourself.

In one step 605 , the initialization of the control device 400 equivalent, can in the storage unit 410 Stored basic parameters are read in. These basic parameters may be the same and / or different than those in step 520 read basic parameters include. For example, the basic parameters information for driving the motor vehicle 100 include, for example, performance data of a drive motor, predetermined or by a driver individually preferred switching points or the like.

In one step 610 For example, a process for determining the center of gravity of the motor vehicle can be carried out. This process 610 preferably contains the in 5 illustrated and described above 500 and provides the center of gravity H and preferably also the horizontal center of gravity position in the longitudinal direction l ₁ and / or transverse direction b ₁ .

In one step 615 is via the first input interface 420 as well as optionally via a further input interface (not shown in detail) a signal read, which indicate a driving condition or another, relevant to the control of the motor vehicle facts. The driving condition data read in this step may include, but not limited to, deflections of the suspensions of the wheels 105 , a rotational speed or a motor control parameter of a drive motor, a steering angle of a steering system, a state of charge of a battery, a fill level of a fuel tank, navigation data of a navigation system, traffic data, weather data, etc.

In one step 620 becomes a process for assisted, semi-automated, automated or autonomous control of the motor vehicle 100 performed in the longitudinal and / or transverse direction. The driving function can ensure that certain maximum roll and pitch values, within which a safe and comfortable driving operation is assumed, are not exceeded. In this case, a maximum driving speed can also be determined in which compliance with the maximum roll and pitch values can be assumed under a current or predetermined driving situation.

In one embodiment, the driving function is at least partially or completely by means of the control device 400 controlled, in another embodiment, the driving function runs at least partially or completely on another processing device. The control device 400 preferably includes a further output interface (not shown in detail) for providing a center of gravity height H and / or certain maximum roll and pitch indicative signal, a warning signal in the present or threatened exceeding the certain maximum speed or for influencing the longitudinal or lateral control of the motor vehicle 100 ,

The invention is not limited to applications in which the motor vehicle 100 is four on two axes 205 . 210 distributed wheels 105 having. The invention is generally applicable to motor vehicles 100 be applied, which have at least three wheels which are mounted on at least two different axes. Although the motor vehicle 100 In the present embodiment, as a right-hand drive vehicle, the present invention can be readily applied to right-hand drive vehicles or center-steering vehicles.

According to the invention, the position of the center of gravity on an actively height-adjustable chassis 120 determined in conjunction with a control unit and other sensors. Active suspensions can actively control individual wheel suspensions of a motor vehicle and thus change, inter alia, the ride height of the vehicle. For recording the height of individual wheels 105 An altitude measuring system can be used as part of the active chassis 120 can be. On the basis of certain height levels and spring stiffness associated Aufbaufedern, each one wheel 105 with the sprung mass m coupled, and a spring-wheel stroke ratio, the wheel loads of the sprung mass can be determined.

If, as in sports vehicles, tires and brakes are driven very differently on the axles, the unsprung mass can be stored in the control unit and added to the sprung mass of the wheels. From the wheel loads of the sprung mass of the front axle and the rear axle, the center of gravity position in the vehicle longitudinal direction and in the vehicle transverse direction can be determined. These values can also be determined by conventional trolleys if they are equipped with position measuring sensors. When determining the center of gravity position in a vertical position of the vehicle in the vertical direction, the vehicle can be raised by an active chassis on an axle. If the vehicle is around the value H is raised, the height of the center of gravity can be calculated.

LIST OF REFERENCE NUMBERS

100

motor vehicle

105

Wheel (VL: front left, front right: right: HL: rear left, rear right: HR)

110

body

115

main emphasis

120

landing gear

125

actuator

130

footprint

205

front axle

210

rear axle

215

steering wheel

400

control device

405

processing unit

410

storage unit

415

Output interface

420

first input interface

425

displacement sensor

430

second input interface

435

A web sensor

440

door sensor

445

Interior monitoring system

450

Seat occupancy sensor

455

ignition sensor

460

speed sensor

500

method

505

Reading sensor data

510

Judging condition

515

Reading in basic data

520

Reading sensor data

525

Determine horizontal center of gravity

530

Drive active chassis

535

Reading sensor data

540

Determining suspension reaction

545

Determine center of gravity

600

method

605

Reading in basic data

610

Determine center of gravity (center of gravity)

615

Reading in driving status data

620

Control of automotive functions

b

gauge

b1

Center of gravity in transverse direction

F _Ges

Sum of all wheel loads of the sprung mass

F _HA

Wheel load of the sprung mass on the rear wheel axle

F _HL

Wheel load, rear left

F _HR

Wheel load, rear right

F _L

Sum of the wheel loads of the sprung mass on the left wheels

F _R

Sum of the wheel loads of the sprung mass on the right wheels

F _VA

Wheel load of the sprung mass on the front wheel axle

F _VL

Wheel load front left

F _VR

Wheel load front right

l

Wheelbase

l1

Center of gravity in the longitudinal direction

G

acceleration of gravity

H

Gravity height

H

altitude change

m

entire sprung mass

R

Wheel diameter

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 10053605 B4 [0003]

Claims (13)

A method (500) for determining a center of gravity height (h) of a motor vehicle (100), the method (500) comprising the steps of: changing a ride height of a wheel (105) of the motor vehicle (100) by means of an active chassis (120); Determining (540) a resulting ride on a wheel (105); and determining (545) the center of gravity height (h) based on the detected ride height. Method (500) Claim 1 wherein the response includes a change in ride height (H) on another wheel (105) of the motor vehicle (100). Method (500) Claim 2 wherein the change of the ride height (H) on wheels (105) of a common axle (205) of the motor vehicle (100) is determined. Method (500) Claim 3 in that the activation (530) comprises a common activation of actuators (125) of the active chassis (120) assigned to the predetermined axis (205) of the motor vehicle (100). A method (500) according to any one of the preceding claims, wherein determining (545) the center of gravity height (h) takes into account at least one of the following parameters: a wheel diameter (R) of at least one wheel (105) of the motor vehicle (100); a wheel load of at least one wheel (105) of the motor vehicle (100); an entire sprung mass (m) of the motor vehicle (100); a center distance (I) of the motor vehicle (100); a horizontal center of gravity (l ₁ , b ₁ ) of the motor vehicle (100); an unsprung mass of at least one wheel (105) of the motor vehicle (100). Method (500) according to one of the preceding claims, wherein the method (500) is performed when the motor vehicle (100) is at a standstill. The method (500) of any one of the preceding claims, wherein the steps of driving (530) the landing gear (120), determining (540) the response, and determining (545) the center of gravity altitude (h) are performed based on the response only when at least one triggering condition is met, the triggering condition being selected from the group comprising: an ignition of the motor vehicle (100) has been actuated; a door of the motor vehicle (100) has been opened and / or closed; a change in a load and / or seat occupancy of the motor vehicle (100) has been detected; an occupant restraint system of the motor vehicle (100) has been activated and / or deactivated. Method (600) for controlling a motor vehicle (100) using an active chassis (120), wherein an algorithm used to control the motor vehicle (100) takes into account a center of gravity height (h) of the motor vehicle (100), wherein the center of gravity height (h) by means of determining a process (610) comprising the steps of: driving (530) the active landing gear (120); Determining (540) a response of the active landing gear (120); and determining (545) the center of gravity height (h) based on the determined response. Method (600) according to Claim 8 wherein the process (610) comprises a method (500) according to any one of Claims 1 to 7 includes. Method (600) according to Claim 8 wherein the method (600) comprises automated, semi-automated or autonomous driving control. An apparatus (400) for controlling a motor vehicle (100), the apparatus comprising: an output interface (415) for outputting a first signal to an active chassis (120) of the motor vehicle; a first input interface (420) for receiving a second signal indicative of a response of the active landing gear (120); a processing unit (405) coupled to the output interface (415) and the first input interface (420) for generating the first signal to drive the active landing gear (120) to provide the first signal to the first interface and to determine a centroid height (405); h) of the motor vehicle (100) on the basis of the received second signal. Device (400) after Claim 11 wherein the processing unit (405) for performing the method (500) according to one of Claims 1 to 7 and / or for carrying out the method (600) according to one of Claims 8 to 10 is set up. Motor vehicle (100) with a body (110) and wheels (105) and a control device (400) for controlling motor vehicle functions, wherein the control device (400) according to Claim 11 or 12 is trained.

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