DE10306228B4 - Actuator for active chassis control - Google Patents

Abstract

Actuator for active chassis control, with an arranged between the wheel (6) and structure (3), the rolling and pitching movements compensating, actuator which an actuator torque or Aktuatorkraft for roll and pitch compensation and additionally an actuator torque or Aktuatorkraft to reduce the Aufbauhubbewegung the structure (3) according to the skyhook principle provides such that the vertical wheel movement via a passive damping between the wheel (6) and structure (3) and on the Tilgerwirkung of the mechanical system is reduced, the Tilgerwirkung on an internal damping of the actuator and / or or a spring-loaded Tilgermasse is realized and wherein
the Lehr'sche construction damping measure D _Ai at the wheel i between 1.0 and 1.5 and
the Lehr wheel damping ratio D _Ri on the wheel i is between 0.05 and 0.1.

Description

The The invention relates to an actuator for active chassis control, in particular for compensating the roll, pitch and stroke movement of the Vehicle structure and dynamic wheel load fluctuations.

In the DE 100 43 711 A1 is described a hydraulic system for an active chassis, which essentially serves for roll and pitch compensation and for the eradication of the wheel vibrations. The actuator torque of this system is given by: M actuator = M roll compensation + M Nick compensation (1)

The torques M _{roll compensation} and M _{pitch compensation} are constantly re-provisioned according to the respective roll and pitch conditions of the vehicle. About the Tilgerwirkung the system, the wheel vibrations are damped, which can be achieved with a simultaneous reduction of the body damping additionally a reduction in body acceleration to 10% compared to a conventional vehicle.

In the pamphlets DE 43 03 160 A1 and DE 195 21 747 A1 Systems for controlling and / or regulating a motor vehicle chassis or a device for roll stabilization and level control are described which represent relatively complex and cost-intensive solutions with a high energy requirement.

The publication DE 41 17 897 A1 describes a complex system for generating signals for controlling or regulating a controllable in his movements running or chassis. Signals are determined which represent the vertical movement of the bodywork at selected locations and from this conclusions are drawn on the lifting, rolling and pitching movements. This is followed by a weighting of these movements and then the control signals for the actuators are determined.

there no absorber effect is over the self-damping in the actuator or over caused a spring-loaded absorber mass, but over a Hydraulic cylinder in conjunction with a throttle plate.

A spring-loaded absorber mass in the form of a simple actuator is made DE 100 43 711 A1 and DE 199 58 178 C1 known. These solutions do not work according to the skyhook principle and only insufficiently compensate for the vehicle body skid.

task The invention is therefore an actuator for active suspension control to create, in addition to the compensation of roll and pitch movement the vertical body acceleration significantly reduced.

This object is achieved with the features of the first claim. In this case, an actuator for active suspension control for the compensation of roll, pitch and stroke movement of the vehicle body is used, to reduce the lifting movement active Skyhook damping is used and the vertical wheel movement via a passive damping between the wheel and body and on Tilgerwirkung the mechanical system is reduced, wherein the Tilgerwirkung is realized by an internal damping of the actuator and / or or a spring-loaded absorber mass and wherein
the Lehr'sche construction damping measure D _Ai at the wheel i between 1.0 and 1.5 and
the Lehr wheel damping ratio D _Ri on the wheel i is between 0.05 and 0.1.

The actuator between body and wheel, in addition to the actuator torques for roll and pitch compensation, provides an actuator torque M _{Sky i} for reducing the buildup stroke (see Equation 2). On a separate damper between the wheel and body can be omitted if the passive wheel damping on the internal damping in the swing motor ( 1 ) (eg specific installation of throttle points). This is possible because the vertical wheel movement is coupled with the rotational movement of the swing motor rotor.

According to the invention, a compensating gas volume per wheel is integrated into the hydraulic system for free vertical wheel movement with simultaneous action of the actuator torque M _actuator , which has a wheel-related vertical stiffness C _{A, gas i} of preferably 2000 to 100000 N / m.

The effective Aufbaufedersteifigkeit c _Ai results as a parallel circuit of main assembly spring C _{A, main i} and superstructure gas spring of the compensation gas volume c _{A, gas i} according to equation (11).

The Tilgereigenfrequenz is preferably tuned to the Tilgerfeder c _Ti to 0.7 to 0.9 times the Radeigenfrequenz and selected as Tilgerdämpfungsmaß D _{Ti is} a value of 0.1 to 0.2, wherein the absorber mass is preferably 4 ... 6 kg should.

CAi = CA,Haupt i + CA,Gas i (11)

c_Ai [N/m]

– wirksame Aufbaufederkonstante am Rad i

c_{A,Haupt i} [N/m]

– Aufbau-Hauptfederkonstante am Rad i

c_{A,Gas i} [N/m]

– Aufbau-Gasfederkonstante vom Ausgleichs-Gasvolumen bezogen auf das Rad am Rad i

c_Ri [N/m]

– Reifenfederkonstante am Rad i

c_Ti [N/m]

– Tilgerfederkonstante am Rad i

D_Ai [–]

–Lehr'sches Aufbau-Dämpfungsmaß am Rad i

D_Ri [–]

– Lehr'sches Rad-Dämpfungsmaß am Rad i

D_Ti [–]

– Lehr'sches Tilger-Dämpfungsmaß am Rad i

F_{D,ges i}[N]

–Gesamt-Dämpfkraft zwischen Aufbau und Rad i

F_{D,passiv i} [N]

– passive Dämpfkraft zwischen Aufbau und Rad i

F_{D,Sky,aktiv i} [N]

– aktive Skyhook–Dämpfkraft am Rad i

i [–]

– Radindex

L_red [m]

– reduzierter Hebelarm zur Umrechnung der Skyhook-Dämpferkraft Mitte Rad zum Aktuator am Rad i

m_Ai [kg]

– anteilige Aufbaumasse am Rad i

m_Ri [kg]

– Radmasse vom Rad i

m_Ti [kg]

– Tilgermasse am Rad i

M_{Sky i} [Nm]

– Skyhook-Aktuatormoment am Rad i

Ż_Ai [m/s]

– Vertikalgeschwindigkeit vom Federanlenkpunkt der Aufbaufeder am Aufbau am Rad i

Ż_Ri [m/s]

– Vertikalgeschwindigkeit vom Rad i

Ż_Ti [m/s]

– Vertikalgeschwindigkeit von der Tilgermasse am Rad i

ρ_Ai [Ns/m]

– Aufbaudämpfungskonstante am Rad i

ρ_Ri [Ns/m]

– Raddämpfungskonstante am Rad i

ρ_Ti [Ns/m]

– Tilgerdämpfungskonstante am Rad i

Unlike the solution after DE 100 43 711 A1 Instead of the passive damping of the build-up stroke, an active skyhook damping is used and provided as an additional actuator torque M _{Sky i} . That is, the equation (1) changes as follows: M Actuator i = M Roll compensation i + M Nick compensation i + M Sky i (2) M Sky i = L red i · F D, Sky, active i (3) F D, Sky, active i = -Ρ Ai · ¯ Ai (4) F D, passive i = -Ρ Ri · ¯ Ai + ρ Ri · ¯ Ri (5) F D, ges i = F D, Sky, active i + F D, passive i (6)

C Ai = C A, main i + C A, gas i (11)

c _Ai [N / m]

- effective body fatigue constant on the wheel i

c _{A, main i} [N / m]

- Construction main spring constant at the wheel i

c _{A, gas i} [N / m]

- build-up gas spring constant of the compensation gas volume relative to the wheel on the wheel i

c _Ri [N / m]

- Tire spring constant on the bike i

_cTi [N / m]

- Tilgerfederkonstante on the bike i

D _Ai [-]

-Rehr'sches construction damping measure on the bike i

D _Ri [-]

- Lehr's wheel damping measure on the bike i

D _Ti [-]

- Lehr's absorber damping measure on the wheel i

F _{D, ges i} [N]

Total damping force between body and wheel i

F _{D, passive i} [N]

- passive damping force between body and wheel i

F _{D, Sky, active i} [N]

- Active Skyhook damping force on the bike i

i [-]

- wheel index

L _red [m]

- reduced lever arm to convert the Skyhook damper force center wheel to the actuator on the wheel i

m _Ai [kg]

- Proportional body mass on the bike i

m _Ri [kg]

- Wheel mass from the wheel i

m _Ti [kg]

- Tilgermasse on the bike i

M _{Sky i} [Nm]

- Skyhook actuator torque on the wheel i

Ż _Ai [m / s]

- Vertical speed of Federanlenkpunkt the body of the construction on the bike i

Ż _Ri [m / s]

- vertical speed of the wheel i

Ż _Ti [m / s]

- vertical speed of the absorber mass on the wheel i

ρ _Ai [Ns / m]

- Body damping constant on the bike i

ρ _Ri [Ns / m]

- Raddämpfungskonstante on the bike i

ρ _Ti [Ns / m]

- absorber damping constant on the wheel i

In order to determine the vertical body speeds Ż _Ai, an acceleration sensor for measuring body acceleration Ż _Ai is installed in each spring connection point of the bodywork springs. Via an integration amplifier, the speed Ż _{Ai is} determined from the acceleration Ż _Ai and multiplied by the skyhook build-up constant, so that the skyhook damping force F _{D, sky, active i} according to equation (4) results.

The calculation of the actuator torque M _actuator via the equations 2 to 4 can advantageously take place in a microprocessor. For the built-up damping measure D _Ai , a value of 1.0 to 1.5 is preferably selected.

The actuator torque M _actuator is preset to a hydraulic system as a manipulated variable and converted by an actuator (eg swivel motor) into an effective torque for controlling the mechanical system according to the prior art.

The advantage over the known system after DE 100 43 711 A1 consists in a significant improvement of the vertical vibration comfort. By means of dynamic simulation, reductions in the effective body acceleration of more than 50% compared to a conventional vehicle were determined.

Since according to the invention only the Aufbauhubbewegung is attenuated by Skyhook (equations 5 to 7) and the wheel damping passive, the actuator must operate essentially in the built-up frequency range f <2 Hz, so that the power consumption for the Skyhook attenuation is relatively low (P _eff < 100 W, P _max <1000 W per wheel for luxury class cars).

Since the passive vibration damper is mounted for wheel damping between body and wheel, in addition to the wheel movements and the body movements are damped, so that the energy required for the active skyhook damping of the structure is reduced:
According to equation (7), the proportion of the active damping force ρ _Ai · Ż _{Ai is} reduced by the passive component of the structural damping ρ _Ri · Ż _Ai

Simulation results showed that extended Skyhook damping on the wheel movement does not work: F D, Sky, active i = -Ρ Ai · ¯ Ai + ρ Ri · ¯ Ri (12)

at the extended Skyhook damping Although the vibration damper saved between body and bike, but for the actuator must be up in the wheel frequency range from 10 to 15 Hz. That means one increased Power requirement for the hydraulic system and leads to noise problems in the vehicle.

characters

1 : Representation of a system with swing motor as actuator

2 : Representation of a hydraulic plan for a system with swing motor as actuator

3 : Illustration of a system with hydraulic cylinder as actuator

In 1 becomes an actuator in the form of a slewing motor 1 used as an actuator for active chassis control. The swivel motor 1 is on the handlebars 5 over the absorber arms 8th and 9 attached. On the rotor of the swing motor 1 is the lever 4 attached, the actuator torque on the pivot lever 2 in the hinge point D2 on the body 3 supported.

The driver 5 is known on the one hand on the wheel 6 and on the other hand, at the construction 3 hinged. The swivel motor 1 acts by a spring bearing with a Tilgerfeder 7 at the same time as absorber mass. This is the swing motor 1 via a four-bar linkage on the handlebar 5 attached. The four-bar linkage is characterized by two mutually superposed Tilgerarme substantially parallel 8th . 9 , both on the swivel motor 1 as well as on the handlebar 5 (There in the hinge points D3 and D4) are pivotally mounted. Between the swing motor 1 and the handlebar 5 are the absorber spring 7 and the absorber 7a arranged.

In the system with swing motor 1 to 1 and 2 is the absorber mass from the swing motor 1 and the proportionate masses of the handlebars 2 . 4 . 8th and 9 together.

To 1 and 2 is used to determine the vertical body speeds Ż _Ai in the spring connection point 12 the bodybuilder 11 at the construction 3 an acceleration sensor 13 appropriate. In the control unit 14 is calculated by integration of the acceleration Ż _Ai, the speed Ż _Ai and multiplied by the skyhook build-up damping constant, so that the Skyhook damping force F _{D, Sky, active i} results according to equation (4).

The calculation of the actuator torque M _actuator according to equations 2 ... 4 takes place in the microprocessor of the control unit 14 , where preferably a value of D _Ai = 1.0 ... 1.5 is to be selected for the structural damping measure.

The amount of actuator torque | M _actuator | | is from the controller 14 a hydraulic pressure control valve 15 specified as a manipulated variable and via a directional control valve 16 from the swing motor 1 converted into an effective torque for controlling the mechanical system.

The directional valve 16 is dependent on the sign of the actuator torque M _{actuator i} via the control unit 14 controlled, bringing the swing motor 1 generates the desired moments for the rebound and rebound of the suspension.

To increase the reaction rate is in front of the pressure control valve 15 a hydraulic accumulator 18 provided, which in conjunction with the pressure relief valve 19 always ensures a sufficient flow rate with high pressure.

The returning hydraulic oil from the swing motor 1 and from the pressure control valve 15 is in the container 20 caught and the hydraulic pump 21 made available.

For optimal control of the driving behavior on the actuator torque M _{actuator i} are further vehicle measured variables. (eg lateral acceleration, steering angle, driving speed) via sensors 22 in the control unit 14 evaluated.

Furthermore, sensors for hydraulic control 23 For example, pressure sensors, switch detection sensors, oil level sensor, evaluated in the control unit and output as control pulses for the hydraulic components.

To enable free vertical wheel movements with simultaneous action of the actuator torque M _{actuator i} is a compensation gas volume 17 integrated per wheel in the form of a memory in the hydraulic system, which preferably has a related to the wheel vertical stiffness c _{A, gas i} from 2000 to 100000 N / m.

In 3 a variant of the actuator according to the invention is shown in which as actuator instead of a slewing motor 1 a hydraulic lifting cylinder 24 is used.

From the illustration in 3 is also the principal mode of action of the Skyhook principle apparent, which the system with swing motor after 1 and 2 equivalent. The absorber mass m _Ti 25 preferably has a weight of 4 to 6 kg. The Tilgereigenfrequenz is about the Tilgerfeder 7 tuned to the 0.7 to 0.9 times the Radeigenfrequenz.

For the absorber damping factor D _Ti , a value of 0.1 to 0.2 has proved to be advantageous.

In the case of the system 3 It is also possible to dispense with the use of a damper for additional damping of the wheel vibrations, which, however, reduces the comfort improvements compared to a system with absorber (according to simulation results by more than 10%).

Claims (7)

Actuator for active chassis control, with one between wheel ( 6 ) and construction ( 3 ), the rolling and pitching movements compensating, actuator which an actuator torque or Aktuatorkraft for roll and pitch compensation and additionally an actuator torque or Aktuatorkraft to reduce the Aufbauhubbewegung the structure ( 3 ) according to the skyhook principle provides such that the vertical wheel movement via a passive damping between wheel ( 6 ) and construction ( 3 ) and on the absorber effect of the mechanical system is reduced, wherein the Tilgerwirkung on an internal damping of the actuator and / or a spring-loaded absorber mass is realized and wherein the Lehr'sche structure damping amount D _Ai i i between 1.0 and 1 , 5 and the Lehr wheel damping ratio D _Ri at the wheel i is between 0.05 and 0.1. Actuator according to claim 1, characterized in that the actuator as a swivel motor ( 1 ) or as a hydraulic cylinder ( 24 ) is trained. Actuator according to claim 1 or 2, characterized in that the passive wheel damping either via the internal damping in the swing motor ( 1 ) or via an additional damper. Actuator according to one of claims 1 to 3, characterized in that the internal damping in the swivel motor ( 1 ) is adjusted via targeted throttle bodies according to the required wheel damping D _Ri . Actuator according to one of claims 1 to 4, characterized in that for the free vertical wheel movement with simultaneous action of the actuator torque M _{actuator i} a compensation gas volume ( 17 ) is integrated per wheel in the hydraulic system, which one on the wheel ( 6 ) has vertical stiffness c _{A, gas i} of 2000 to 100000 N / m. Actuator according to one of claims 1 to 5, characterized in that the effective Aufbaufedersteifigkeit C _Ai from the parallel circuit of superstructure main spring C _{A, main i} ( 11 ) and build-up gas spring of the compensation gas volume C _{A, gas i} ( 17 ). Actuator according to one of claims 1 to 6, characterized in that the Tilgereigenfrequenz at a damping mass of 4 ... 6 kg on the Tilgerfeder c _Ti ( 7 ) is tuned to the 0.7 to 0.9 times the Radeigenfrequenz and the Tilgerdämpfungsmaß D _{Ti is} from 0.1 to 0.2.