Modelling and control of active power steering systems for heavy trucks
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Applied mechanics (MPAME), MSc
Publicerad
2023
Författare
Ashok Kumar, Sharath Chandra
Erikmats, Emil
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Transportation via trucks constitutes an important part of the logistics chain. Today’s trucks can take a front axle load of approximately 8 tonnes. To be able to
maneuver at high front axle loads, the driver needs assistance from additional power
sources. The additional power can be provided through different sources in different steering topologies: Hydraulic Power Steering (HPS), Electric Power Steering
(EPS) or Electro-Hydraulic Power Steering (EHPS), where HPS and EHPS are more
common today. Some benefits of EPS over the other two are reduced energy consumption, improved autonomous drivability, and the absence of hydraulic oils which
can contaminate soil, groundwater and seawater. However, hydraulics are faster
than electromechanical systems.
This thesis aims to see if acceptable steering performance can be achieved with EPS
and compare it to EHPS by modelling, designing controllers and simulating the
complete vehicle-driver-ground systems. The version of EHPS chosen was a Volvo
Dynamic Steering-like (VDS-like) topology. The mechanical systems were mainly
modeled using tools in Dymola but also in MATLAB, Simulink, and TruckMaker
for Simulink (TM4SL) environment. The Dymola model of the VDS-like model was
validated by comparing it to Volvo’s steering black box model at Chalmers. The
control was developed in MATLAB and Simulink, where PID controller was selected for the motor and the outer control scheme being H2 for energy optimization.
The mechanical system, the motor model, and the controllers were then connected
in TM4SL. Evaluation on TruckMaker was conducted by simulating two scenarios
namely, path following in a figure of eight and in a wheel lock scenario.
The models of the two steering systems developed were found to be acceptable while
the designed boost for the EPS system also performed supportively. The controller
however did not produce the anticipated behaviour.
Beskrivning
Ämne/nyckelord
Power steering system , Electric Power Steering system (EPS) , Robust and Nonlinear Control , Electro-Hydraulic Power Steering system (EHPS)