Design and simulation of a vertical dynamics control system within an advanced simulation environment

master's thesis

• Title (croatian): Sinteza i simulacija sustava upravljanja vertikalnom dinamikom vozila u naprednom simulacijskom okruženju
• Author: Paolo Berljavac
• Mentor: Joško Deur (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2021-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

This thesis presents the design of a fully-active and a semi-active suspension control system,
their implementation in an advanced simulation environment and a comparative performance
analysis. The comparative analysis includes a passive suspension, optimal fully- and semi-active suspensions based on a linear quadratic regulator, a reduced-order control of fully-active
suspension and a Skyhook control of semi-active suspension. The reduced-order and Skyhook
controllers require a limited sensor suite, which is frequently implemented on high-end
passenger vehicles. This gives an insight into how practical controllers compare to benchmark
optimal controllers.
The controller performance is analyzed in two vertical dynamics test procedures - sine bump
and sine sweep and two lateral dynamics test procedures – lane change (ISO 3888-1) and
Hockenheim short track lap time simulation.
Furthermore, a robustness analysis is carried out with respect to actuator dynamics in terms of
force gradient limitation and actuator bandwidth. The robustness analysis is extended to the
case of included parameter uncertainties such as rear axle static load change and the addition
of noise and offset to feedback loop measurement signals.
The reduced-order fully-active suspension controller and Skyhook semi-active suspension
controller resulted in significant improvements in terms of comfort in typical vertical dynamics
test procedures compared to a passive suspension. The optimal fully- and semi-active
suspension controller provide only slightly better results than the practical controllers with
respect to most metrics. The comparative analysis of controllers, based on a quarter car model
and implemented on the full vehicle model, in lateral dynamics test procedures showed
acceptable improvements in terms of vehicle stability and negligible handling improvements.
This indicates that a full vehicle model-based controller design would be more appropriate for
greater handling metric improvements.

Abstract (croatian)

U ovom je radu prikazana sinteza aktivnih i polu-aktivnih ovjesa putničkih vozila, njihova
implementacija u napredno simulacijsko okruženje te usporedna analiza performansi sustava
upravljanja. U radu su uspoređeni pasivni ovjes, optimalni aktivni i polu-aktivni ovjes temeljeni
na primjeni linearnog kvadratnog regulatora, aktivni ovjes s regulatorom reduciranog reda, te
polu-aktivni ovjes sa Skyhook upravljanjem. Potonji aktivni i polu-aktivni ovjes koriste
ograničen broj senzora koji su najčešće dostupni na putničkom vozilu.
Usporedna analiza temelji se na primjeni karakterističnih procedura vertikalne dinamike vozila
poput ceste oblika poluvala sinusoide (engl. sine bump), ceste s promjenjivom frekvencijom
vala sinusoide (engl. sine sweep) te procedura bočne dinamike vozila – promjena trake (engl.
lane change) i simulacija brzog kruga trkaće staze Hockenheim short (engl. lap time
simulation).
Osim usporedne analize različitih upravljanja, provedena je analiza robustnosti regulatora s
obzirom na dinamiku aktuatora poput ograničenja gradijenta sile te brzine odziva na
performanse upravljanja u navedenim procedurama. Ispitivanje robustnosti regulatora
prošireno je na slučajeve promijenjenog statičkog opterećenja osovine vozila te unos šuma
(engl. noise) i odstupanja (engl. offset) u mjerene signale.
Primjena regulatora reduciranog reda te polu-aktivnog ovjesa sa Skyhook upravljanjem dovodi
do značajnih poboljšanja komfora u testnim procedurama vertikalne dinamike u usporedbi s
pasivnim ovjesom. Performanse optimalnih regulatora aktivnog te polu-aktivnog ovjesa su
neznatno bolje od odgovarajućih regulatora reduciranog reda te polu-aktivnog ovjesa sa
Skyhook upravljanjem. Usporedna analiza regulatora, temeljenih na četvrtinskom modelu
vozila te primijenjenih na puni model vozila, u vidu bočne dinamike je pokazala prihvatljiva
poboljšanja po pitanju stabilnosti i neznatne razlike u vidu upravljivosti vozila te se upućuje na
primjenu regulatora dizajniranog na temelju modela cijelog vozila u svrhu poboljšanja tih
indeksa performansi.

• Keywords: control system design; comfort; handling; vehicle dynamics; active suspension
• Keywords (croatian): upravljački sustavi; komfor; upravljivost; dinamika vozila; aktivni ovjes
• Language: english
• URN:NBN: urn:nbn:hr:235:078784
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2023-07-08
• Created on: 2021-07-12 08:18:02