Steering Effects Of Active Suspensions
Typ
Examensarbete för masterexamen
Program
Systems, control and mechatronics (MPSYS), MSc
Publicerad
2019
Författare
Birur Satish, Akshay Bharadwaj
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Automotive suspension systems have traditionally been a compromise between ride
comfort,road handling and load carrying. Due to these conflicting demands, semiactive
suspension has been an important feature among premium car manufacturers.
The type of active suspension considered in this thesis is an active anti-roll bar
system (AARB). The main objective of the AARB system is to provide roll-over
protection and better isolation to the passengers from the disturbances induced due
to road irregularities.
While the active suspension provides better comfort by attenuating the vertical and
roll disturbances to a great extent, it has certain adverse effects too. Active control
of suspension triggers the lateral vehicle movement due to kinematics and compliance
(K&C) of the wheel suspension. The suspension parameters such as bump
steer, roll steer and camber steer produces some lateral tyre force which needs to be
compensated. To ensure stability of the vehicle, lateral disturbances caused by road
bumps, crowned road and road banking needs to be attenuated. The master thesis
involves implementation of the AARB controller to improve stability and reduce the
steering effort while driving on the road with above mentioned disturbances. The
controller can be integrated with active steering system to reduce the overhead on
the steering actuator and increase steer-ability in auto-pilot mode. Also, the influence
of K&C parameters on steering torque and yaw rate is studied using a linear
kinematic model developed in CarMaker. Further, AARB controller is extended to
handle cornering scenarios. The control strategy developed includes a state feedback
LQR, LQI and robust H1 controller and validated with two different K&C setups
and their performance is compared.
In conclusion, simulation results show that there is potential in the AARB system
to reduce driver steering effort in driver-in-loop and increase steering range in autopilot
while using a certain kind of K&C setup.
Beskrivning
Ämne/nyckelord
Active suspension , Active anti-roll bar , H1 control , K&C , linear kinematic model , Reduce steering effort