DE102021131579A1 - Method for controlling or regulating a controllable bearing of a vehicle - Google Patents

Abstract

The invention relates to a method for controlling or regulating a controllable bearing (6) of a vehicle (1), the vehicle (1) having a chassis (2), a structure (3) which is elastically mounted relative to the chassis (2), and a mass ( 4), wherein the mass (4) is mounted elastically in relation to the body (3) via at least one controllable bearing (6), comprising the following steps: detecting at least one controlled variable that indicates a movement of the body (3), the chassis ( 2) or a person located in the structure (3), determining a manipulated variable based on the controlled variable to cancel the movement detected via the controlled variable, and controlling the at least one controllable bearing (6) based on the manipulated variable.

Description

The present invention relates to a method for controlling or regulating a controllable mount, in particular an engine mount, in a vehicle. Furthermore, the invention relates to a vehicle that is designed in particular to carry out the method.

In vehicles according to the state of the art, the drive units, for example the engine with a flange-mounted gearbox, are usually mounted elastically in relation to the body via a number of engine mounts. In this case, semi-active bearings can be used, which are adjustable in terms of their degree of damping. This is shown as an example EP 1 249 637 B1 a device for suppressing vibrations in a moving system, in which a magnetorheological fluid in a semi-active bearing is used to reduce the vibration of a motor.

It is the object of the present invention to specify a method for controlling or regulating a controllable bearing of a vehicle that enables safe and comfortable operation of the vehicle. Furthermore, it is the object of the present invention to specify a corresponding vehicle with a controllable bearing, which also enables safe and comfortable operation.

The object is solved by the features of the independent claims. The dependent claims relate to preferred developments of the invention.

The invention is thus achieved by a method for controlling or regulating a controllable bearing of a vehicle. The vehicle is preferably a two-lane road vehicle, in particular a passenger car.

A distinction is made between the following four bearings in the vehicle sector: The "passive bearing" is, for example, an elastomer bearing or a hydraulic bearing. The "switchable mount" can change the properties of the mount (e.g. damping or stiffness) in discrete steps. The "semi-active bearing" can continuously change the properties of the bearing (e.g. damping or stiffness) and is designed, for example, as a magneto-reological bearing. The "active mount" can both continuously change the properties of the mount (e.g. damping or stiffness) and actively set forces using a force actuator.

The at least one “controllable bearing” according to the invention can in principle be any bearing whose properties can be adjusted by means of a corresponding control and/or can provide forces by means of a force actuator. In particular, the controllable bearing has an adjustment actuator that can be correspondingly controlled and can change the property of the bearing. In particular, the controllable bearing can be controlled electronically.

In particular, the at least one “controllable bearing” according to the invention is an active bearing or a semi-active bearing or a switchable bearing.

The vehicle in which the method according to the invention is used includes a chassis and a body. The chassis includes, in particular, four wheels, which are mounted directly opposite the body by means of corresponding spring damper systems or by means of an auxiliary frame opposite the body. Due to this elastic mounting of the chassis relative to the body, the excitation on the road when the vehicle is in use results in a corresponding vibration of the body. Furthermore, the method provides that there is a mass in the vehicle. The mass is in particular a drive unit that is used to drive the vehicle. The mass is mounted elastically in relation to the structure via the at least one controllable bearing. For the sake of clarity, the invention is described using a controllable bearing between the mass and the structure. However, it is also possible that several structurally identical or several different controllable bearings are used to accommodate the mass in the structure and several of these controllable bearings are controlled according to the invention presented here.

1. (i) Zunächst erfolgt ein Erfassen zumindest einer Regelgröße. Diese Regelgröße basiert auf einer Bewegung, insbesondere einer Beschleunigung, des Aufbaus, des Fahrwerks oder einer im Aufbau befindlichen Person (Insasse). Es können mehrere Regelgrößen am Aufbau oder mehrere Regelgrößen am Fahrwerk oder mehrere Regelgrößen an der im Aufbau befindlichen Person erfasst werden. Darüber hinaus ist es auch möglich, die Regelgrößen unterschiedlicher Komponenten, also des Aufbaus, des Fahrwerks und/oder einer im Aufbau befindlichen Person zu erfassen und für die Ermittlung der Stellgröße zu nutzen. Der Aufbau des Fahrzeugs umfasst zumindest die Karosserie.

The basic idea of the invention is based on the fact that the vibration of the actively mounted mass does not necessarily have to be reduced, but that the movement perceived by the occupants in the vehicle, in particular vibration, is decisive and should be reduced as far as possible. In order to achieve this goal, the mass in the vehicle is increased, at least in certain operating modes stands, used as absorbers to reduce the vibration of the body as much as possible. The following procedural steps are provided for this:

1. (i) First, at least one controlled variable is detected. This controlled variable is based on a movement, in particular an acceleration, of the body, the chassis or a person (occupant) located in the body. Several control variables on the body or several control variables on the chassis or several control variables on the person in the body can be recorded. In addition, it is also possible to record the controlled variables of different components, ie the body, the chassis and/or a person located in the body, and to use them to determine the manipulated variable. The structure of the vehicle includes at least the body.

• (ii) Basierend auf der erfassten Regelgröße oder basierend auf den mehreren erfassten Regelgrößen wird in einem Regler eine Stellgröße ermittelt, insbesondere berechnet. Diese Stellgröße wird dabei so ermittelt, dass bei Ansteuerung des zumindest einen ansteuerbaren Lagers eine Tilgung der über die Regelgröße erfassten Bewegung mittels der schwingenden Masse erfolgt.
• (iii) Basierend auf der ermittelten Stellgröße erfolgt ein Ansteuern des zumindest einen ansteuerbaren Lagers, um die Masse, insbesondere die Antriebseinheit, zur Tilgung der über die Regelgröße erfassten Bewegung des Aufbaus und/oder des Fahrwerks und/oder des Insassen zu erreichen. Im Rahmen der Erfindung ist somit nicht vorgesehen, dass die Schwingung der Masse möglichst schnell oder effizient gedämpft wird. Vielmehr basiert die Regelgröße (Zielgröße) darauf, die von den Insassen wahrgenommene Bewegung, insbesondere Beschleunigung oder Schwingung, zu reduzieren.

The movement of the body as a controlled variable can be detected, for example, with an acceleration sensor on the body. For this purpose, a separate sensor can be installed for the method according to the invention; however, it is also possible to use a sensor that is already present in the vehicle. Furthermore, the structure of the vehicle can also include a seat, with the controlled variable being detected by a corresponding sensor, in particular an acceleration sensor, on the seat. By detecting the controlled variable directly on the seat, the movement acting on the occupant, in particular vibration or acceleration, is detected relatively precisely. In order to determine a control variable that is based on the perception of the occupant even more precisely, the movement, in particular vibration or acceleration, can also be recorded directly on the person in the body. For example, via an optical sensor, in particular a camera, the controlled variable can preferably be detected directly on the occupant.

• (ii) Based on the detected controlled variable or based on the multiple detected controlled variables, a manipulated variable is determined, in particular calculated, in a controller. This manipulated variable is determined in such a way that when the at least one controllable bearing is activated, the movement detected via the controlled variable is canceled by means of the oscillating mass.
• (iii) Based on the determined manipulated variable, the at least one controllable bearing is actuated in order to reach the mass, in particular the drive unit, for absorbing the movement of the body and/or the chassis and/or the occupant detected via the controlled variable. The invention therefore does not provide for the vibration of the mass to be damped as quickly or efficiently as possible. Rather, the controlled variable (target variable) is based on reducing the movement perceived by the occupants, in particular acceleration or vibration.

As already described, the mass in the vehicle is preferably the drive unit of the vehicle. The drive unit comprises in particular an internal combustion engine and/or an electric motor and/or a transmission and/or a fuel cell unit. Other components of the drive train can be part of the drive unit. In particular, no additional mass is introduced into the vehicle for damping purposes, but a mass that is already in the vehicle, namely the drive unit, is used to dampen the vibration.

In particular, the eradication takes place in that the controllable bearing is controlled in such a way that a direction of movement of the mass is opposite to a direction of movement of the movement detected via the controlled variable.

As already discussed, the mass, in particular the drive unit, is dampened as quickly as possible in conventional vehicles. In the context of the present invention, however, provision is preferably made for the mass to vibrate in certain operating states, in particular if this improves the perceived vibration comfort for the occupant. This is particularly the case when the directions of movement of the mass and the movement detected via the controlled variable differ and efficient cancellation is possible as a result.

It is preferably provided that the manipulated variable for canceling the movement detected via the controlled variable is determined at least in a frequency range from 5 Hz to 50 Hz. In this frequency range in particular, the mass, in particular the drive unit, can be used as an efficient absorber.

In addition to the controlled variable described, it is possible to record an additional variable. The additional quantity is based on a movement of the mass. When determining the manipulated variable in the controller, the manipulated variable can be based not only on the controlled variable, but preferably also on this additional variable.

The determination of the manipulated variable in the controller is preferably based on one of the following control or regulation approaches: Feedforward Control, in particular FxLMS (Filtered x Least Mean Squared), Optimal Control, in particular LQR (linear quadratic regulator) or LQG (linear quadratic gaussian regulator ), predictive control, in particular MPC (model predictive control), robust control, in particular H∞ control, or intelligent control, in particular fuzzy logic or controllers with artificial neural networks.

The invention also includes a vehicle, in particular designed to carry out the method described above. The advantageous refinements described in the context of the method and the associated claims are correspondingly advantageously applied to the vehicle.

The vehicle includes a chassis, a body elastically mounted relative to the chassis, a mass, in particular a drive unit, and at least one controllable bearing, the mass being elastically mounted relative to the body via the at least one controllable bearing. In particular, the vehicle is constructed as already described in the context of the method.

Furthermore, the vehicle includes a detection unit for detecting the at least one controlled variable, which reflects a movement of the body, the chassis or an occupant; a controller for determining the manipulated variable based on the controlled variable for canceling the movement detected via the controlled variable; and a control unit for controlling the at least one controllable bearing based on the manipulated variable.

The detection unit, the regulator and the control unit can be integrated together in a computing unit. Furthermore, it is possible to arrange the individual units in separate computing units or control devices.

The units can be partially or fully realized by hardware and/or software. Furthermore, it is possible to outsource parts of the calculation of the detection unit and/or the regulator and/or the control unit to a cloud, with the vehicle being connected to the cloud via a corresponding data connection.

• 1 eine rein schematische Ansicht eines erfindungsgemäßen Fahrzeugs zur Durchführung des erfindungsgemäßen Verfahrens,
• 2 ein Diagramm zur Darstellung der Krafteinleitung von der Antriebseinheit auf den Aufbau,
• 3 ein Diagramm zur Darstellung einer translatorischen Beschleunigung des Aufbaus,
• 4 ein Diagramm zur Darstellung einer rotatorischen Beschleunigung des Aufbaus,
• 5 ein Diagramm zur Darstellung der verbesserten Wahrnehmung des Schwingungskomforts bei Durchführung des erfindungsgemäßen Verfahrens, und
• 6 ein Detail einer Recheneinheit zur Durchführung eines erfindungsgemäßen Verfahrens.

Further details, features and advantages of the invention result from the following description and the figures. Show it:

• 1 a purely schematic view of a vehicle according to the invention for carrying out the method according to the invention,
• 2 a diagram showing the introduction of force from the drive unit to the body,
• 3 a diagram to show a translational acceleration of the structure,
• 4 a diagram to show a rotational acceleration of the structure,
• 5 a diagram showing the improved perception of the vibration comfort when the method according to the invention is carried out, and
• 6 a detail of a computing unit for carrying out a method according to the invention.

The following is based on the 1 until 6 a vehicle 1 and the method according to the invention carried out therein are presented.

1 shows purely schematically the essential components of the vehicle 1 here. The vehicle 1 comprises a chassis 2 and a body 3. The chassis 2 is connected to the body 3 in the usual way via corresponding spring damper systems 5. This chassis 2 and the spring damper systems 5 result in a corresponding oscillating movement of the superstructure 3.

Furthermore, the schematic representation of the vehicle 1 in 1 that the vehicle 1 comprises a drive unit 4, which can be generally referred to as mass. The drive unit 4 is, for example, an internal combustion engine and/or an electric motor and/or a transmission and/or a fuel cell unit. The drive unit 4 is connected to the structure 3 via a plurality of controllable bearings 6, in particular active or semi-active bearings. The controllable bearings 6 can be controlled accordingly, so that the degree of damping and/or the spring stiffness of the controllable bearings 6 can be adjusted or a force can be generated and introduced.

Vehicle 1 also includes a computing unit 8. A detection unit 9, a controller 10 and a control unit 11 are part of this computing unit 8.

A control variable on the vehicle 1 is detected by means of the detection unit 9 . The illustration in shows an example 1 a sensor 7, in particular an acceleration sensor, on the structure 3. By means of this sensor 7, the detection unit 9 can detect the movement, in particular acceleration, of the structure 3 over time as a controlled variable. As has already been discussed in the general part of the description, movement values can be recorded as controlled variables at different positions of the structure 3, for example also in the seat, and/or directly on the person located in the structure.

In the arithmetic unit 8, the controller 10 calculates the controlled variable based on the at least one controlled variable. The control unit 11 can use this control variable to control the controllable bearings 6 in such a way that the drive unit 4 can be used as an absorber to reduce the movement of the body 3 .

In principle, very different control and regulation approaches can be used in controller 10, which make it possible, based on the controlled variable, to use the mass, in particular drive unit 4, to reduce the movement of body 3. In the following, two approaches are described in more detail by way of example, which describe control and regulation approaches to be used advantageously, which were checked in simulations for their suitability within the scope of the method according to the invention.

The controller 10 can be a linear-quadratic controller (LQR) in which a cost function V(u) with a different time horizon is minimized using two weighting matrices Q and R in order to find the optimal manipulated variable u. Essentially, the linear-quadratic controller 10 is based on the following formula: $$\underset{\text{and}}{\text{at least}}\text{V}\left(\text{and}\right)=\underset{\text{and}}{\text{at least}}{\displaystyle \underset{0}{\overset{\infty }{\int }}\left(x^{T}Qx+{\mathrm{and}}^{T}R\mathrm{and}\right)\mathrm{i.e}t}$$

The two weighting matrices Q and R are determined for the associated vehicle configuration in tests and/or simulations and stored in controller 10 accordingly. The vector x is the states of the system.

With this control approach, the introduction of force from the drive unit 4 can be reduced in comparison to a passive, for example hydraulic, bearing and, in particular, can have an absorbing effect on the axle forces. 2 shows the total forces acting on structure 3 when using a conventional hydraulic bearing as “hyd structure”. The individual force in the conventional hydraulic bearing on the drive unit 4 is shown as "hyd drive unit".

Furthermore shows 2 the values when using the method according to the invention for controlling the controllable bearing 6, in particular when using the linear-quadratic controller 10. "LQR structure" shows the total forces on the structure 3. "LQR drive unit" shows the individual force on the drive unit 4 Frequency range between 14 Hz and 18 Hz clearly shows that the manipulated variable is selected by the controller 10 in such a way that an opposite direction of force, and in particular therefore also an opposite direction of movement, results from structure 3 and drive unit 4, which means that the movement of the structure is eliminated 3 is coming.

3 and 4 also show the comparison between a conventional bearing of the drive unit 4 via hydraulic bearings and the control of the controllable bearings 6 according to the invention, in the specific example by means of the linear-quadratic controller 10.

3 shows the acceleration of the body 3 in the vertical direction of the vehicle over the frequency. The acceleration of structure 3 with the conventional bearing is marked with "hyd" and the acceleration of structure 3 with LQ controller 10 with "LQR". It is easy to see that in a relatively wide frequency range there is a strong reduction in the acceleration of the structure 3 can be made possible by repayment via the corresponding control of the controllable bearing 6 of the drive unit 4.

In 4 the rotational acceleration around the vertical axis is shown over the frequency. The acceleration of the structure 3 with the conventional hydraulic bearing is again shown with “hyd”. "LQR" shows the acceleration of assembly 3 using the method of the present invention rens with LQ controller 10. Even when considering the rotational movement, a strong reduction in the movement of the structure 3 can be achieved by the LQ controller 10 in a very wide frequency range.

An improvement in vibration comfort perceived by the occupants can be calculated using the overall vibration total value according to ISO 2631-1, for example. This was carried out as part of the experiments with the LQ controller 10 explained above. The result was as follows 5 , according to which the value of the overall vibration total value was over 0.25 when using the conventional hydraulic mounting. In contrast, when using the LQ controller 10, the overall vibration total value of approx. 0.2 was achieved.

In addition, the method according to the invention was carried out using a model predictive controller (MPC), and a significant improvement in vibration comfort was also achieved in this way. When the controller 10 is designed as a model-predicative controller, a cost function V(u) with a finite time horizon is minimized using online optimization of the manipulated variable u. This online optimization is carried out in controller 10 during operation of the vehicle. The model predictive controller 10 optimizes the manipulated variable u based in particular on the following formula: $$\begin{array}{c}V={\displaystyle \sum _{i=1}^{Np}\left(y^T{}_{p\mathrm{right}e\mathrm{i.e}}\left(k+i\right)Q{y}_{p\mathrm{right}e\mathrm{i.e}}\left(k+i\right)\right)}\\ +{\displaystyle \sum _{i=1}^{N_{\mathrm{and}}}\left(\mathrm{\Delta }{\mathrm{and}}^T\left(k+i\right){\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="DE102021131579A1\_0003.png"\; state="\{\{state\}\}">R</figure-callout>}}_1\mathrm{\Delta }\mathrm{and}\left(k+i\right)\right)+{\displaystyle \sum _{i=1}^{N_{\mathrm{and}}}\left({\mathrm{and}}^T\left(k+i\right){\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="DE102021131579A1\_0005.png,DE102021131579A1\_0006.png"\; state="\{\{state\}\}">R</figure-callout>}}_2\mathrm{and}\left(k+i\right)\right)}}\end{array}$$

• Gewichtungsmatrix des Ausgangs; N_u: Steuerungshorizont; Δu: Vektor der Systemschrittweite; R₁: Gewichtungsmatrix der Steuerungsschrittweite; u:
  • Systemeingangsvektor; R₂: Gewichtungsmatrix der Steuergrößen

where: V: cost function; i: iteration variable; N _p : forecast horizon; y _pred : predict system output vector; k: discrete time variable; Q:

• output weight matrix; N _u : control horizon; Δu: vector of the system step size; R ₁ : control step size weight matrix; u:
  • system input vector; R ₂ : weighting matrix of the control variables

6 shows purely schematically the configuration of the arithmetic unit 8 for the model-predictive controller 10. The online optimization with the optimizer 12 and the _{corresponding} model 13 is shown schematically. results. u' in turn is checked further in the model and the resulting value y' _pred is again optimized. The sufficiently optimized manipulated variable u can be used via the control unit 11 to control the controllable bearing 6 .

The simulations have shown that the mode of action with regard to forces and accelerations in the model predictive controller are very similar to the values of the LQ controller, as has already been shown using the 2 until 4 was explained. However, a further improvement results, in particular with regard to the reduction in the movement of the structure 3, due to the online optimization. In addition, the cost function in the model predictive controller can be adjusted in such a way that a further improvement can be achieved with the help of perception-based filters, such as those described in ISO 2631-1. A procedure that goes beyond this preferably includes the calculation of an objective, perception-based variable, in particular the overall vibration total value described above, in the model predictive controller during the online optimization and thus optimizes it directly. This results in a further improvement in vibration comfort.

Reference List

1

vehicle

2

landing gear

3

Construction

4

drive unit (mass)

5

spring damper system

6

controllable warehouse

7

sensor

8th

unit of account

9

registration unit

10

controller

11

control unit

12

optimizer

13

Model

QUOTES INCLUDED IN DESCRIPTION

This list of 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 1249637 B1 [0002]

Claims (10)

Method for controlling or regulating a controllable bearing (6) of a vehicle (1), • wherein the vehicle (1) has a chassis (2), a body (3) elastically mounted relative to the chassis (2) and a mass (4), the mass (4) having at least one controllable bearing (6) relative to the Structure (3) is elastically mounted, comprising the following steps • detecting at least one controlled variable that reflects a movement of the body (3), the chassis (2) or a person in the body (3), • Determining a manipulated variable based on the controlled variable to compensate for the movement recorded via the controlled variable, • and controlling the at least one controllable bearing (6) based on the manipulated variable. procedure after claim 1 , wherein the mass (4) is a drive unit, in particular with an internal combustion engine and/or an electric motor and/or a transmission and/or a fuel cell unit. Method according to one of the preceding claims, in which the controllable bearing (6) is controlled in order to vary its spring stiffness and/or its degree of damping continuously or in more than two stages and/or to set a force. Method according to one of the preceding claims, in which the controllable bearing (6) is controlled such that a direction of movement of the mass is opposite to the movement reproduced via the controlled variable. Method according to one of the preceding claims, in which the spring stiffness and/or the degree of damping of the at least one controllable bearing (6) is/are reduced and/or increased as the amplitude of the controlled variable increases. Method according to one of the preceding claims, a displacement and/or speed and/or acceleration being detected as the controlled variable. Method according to one of the preceding claims, the manipulated variable for canceling the movement detected via the controlled variable being determined at least in a frequency range of 5 Hz to 50 Hz. Method according to one of the preceding claims, in which a movement, in particular acceleration, of the mass (4) is detected as an additional variable and the controlled variable is also determined on the basis of the additional variable. Method according to one of the preceding claims, wherein the manipulated variable is determined by means of an LQ controller or a model predictive controller. Vehicle (1), in particular designed to carry out the method according to one of the preceding claims, • comprising a chassis (2), a structure (3) elastically mounted relative to the chassis (2), a mass (4), in particular a drive unit, the mass (4) being mounted relative to the structure (3 ) is elastically mounted, • a detection unit (9) for detecting at least one controlled variable that reflects a movement of the body (3), the chassis (2) or a person in the body (3), • a controller (10) for determining a manipulated variable based on the controlled variable to compensate for the movement detected via the controlled variable, • and a control unit (11) for controlling the at least one controllable bearing (6) based on the manipulated variable.

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