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RPY angle of cars and other land vehicles (English roll, pitch, yaw, German roll, pitch, yaw angle)

Waver or rollers is the technical language designation for the rotary motion of a land vehicle to the longitudinal axis of a vehicle-fixed coordinate system as a result of uneven ground or when cornering.

In watercraft and aircraft, this movement is primarily referred to as rolling . Colloquially, the term is also used, for example, in the sense of “moving unsteadily”.

When cornering, for example, land and water vehicles usually lean outward due to centrifugal force . The resulting roll angle depends on the lateral acceleration , vehicle mass , center of gravity and chassis structure .

The roll center or roll center is the instantaneous center of roll of the body of a vehicle with respect to the vehicle coordinate system in the vertical plane through the front or rear axis . When the wheel suspensions move, the position of the roll centers and the roll axis changes. They are therefore constantly changing in accordance with the changing load cases while driving.

Roll stabilization

Nowadays, electronically controlled, active anti-roll bars are installed in production cars to avoid rolling (roll stabilization), for example at BMW the so-called ARS (active roll stabilizer) in the special equipment Dynamic Drive (alternative designation Adaptive Drive, Active Roll Stabilization), at Mercedes ( Active Curve System), or at Porsche (Porsche Dynamic Chassis Control PDCC).

The Active Body Control (ABC) from Mercedes does not have any torsion bar springs that are added to the suspension springs during passive stabilization to reduce swaying. The vehicle body is held horizontally by a hydraulic system. A unidirectional hydraulic cylinder (plunger) is attached to each spring strut. Due to the variable pressure in the cylinder, the respective spring preload can be continuously adjusted. The pressure is regulated by a computer, which evaluates signals from acceleration sensors in the vehicle. Higher-frequency vibrations are dampened by conventional vibration dampers (shock absorbers). The system pressure is provided by a belt-driven radial piston pump . The system is only available for rear-wheel drive models .

Individual evidence

  1. Wolfgang Matschinsky: Wheel guides of road vehicles: kinematics, elasto-kinematics and construction . 2nd Edition. Springer, 2007, ISBN 978-3-540-71196-4 , pp. 4-5 . As a vehicle-fixed coordinate system, the system is used with a vehicle-fixed or with a y-axis parallel to the road surface ("leveled" vehicle-fixed system).
  2. Lecture on Embedded Software Engineering in the Automotive division at the Technical University of Dresden, rotational movements. (PDF; 2.3 MB) p. 24 , accessed on January 6, 2019 .
  3. ^ Online Duden Bibliographisches Institut GmbH. 2012, accessed January 6, 2019 .
  4. Dynamic Drive. Retrieved January 6, 2019 .
  5. Adaptive Drive. Retrieved January 6, 2019 .
  6. ACTIVE CURVE SYSTEM. Retrieved January 6, 2019 .
  7. Subdued fickleness: ideas from chassis technology. Retrieved January 6, 2019 .