Longitudinal Control Design for Autonomous HDVs
2019 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Student thesis
Abstract [en]
Autonomous vehicles are evolving from a futuristic dream to current realityas technology becomes more and more mature. However, their presence on thehighways will demands precise control over lateral and longitudinal positioning.This thesis, completed at Scania Group AB in Södertälje, mainly focuses on thedesign of longitudinal controllers for trajectory tracking without compromisingalready mature control solutions. To this end, a virtual vehicle is created toextrapolate where the vehicle is supposed to be in time, and its position andvelocity are used as reference inputs. Then, two different control strategies (aPD controller and a lead compensator) based on position error and velocityerror are developed. A breaking algorithm is also developed to use servicebrakes on an Heavy-duty vehicle effectively. Numerical studies highlight thatthe proposed controllers exhibit excellent performance while tracking both positionand velocity trajectories. The proposed controllers are examined in threedifferent test cases: varying velocity, executing lane changes, and driving in anenvironment with significant changes in topology. In all test cases, the positionerror is less than 1m, while the velocity error is less than 0.5m/s. Comparedto the existing controller, developed in Scania Group AB, these controllers improvethe tracking performance significantly. Also, both controllers improverobustness against lateral changes and exogenous forces.
Abstract [sv]
I och med att forskningen mot det första autonoma fordonet fortgår, såhar många komplexa problem fått lösningar och uppmärksamheten har väntsmot andra problem. Detta examensarbete, utfört på Scania gruppenAB i Södertälje,utforskade longitudinella regulatorer som minimerar positionsfel ochhastighetsfel för lastbilar, genom att implementera en två regulatorer i kaskad,en som styr på positionsfel och en som styr på hastighetsfel. Det autonoma fordonssystemetutnyttjade path following, vars system modifierades för att skapaett virtuellt fordon som följer hastighetsprofilen perfekt och möjlighetgör trajectorytracking istället. De två regulatorer som implementerades var en PDregulator samt en fasavancerade regulator. Regulatorerna utvärderades i treolika test: Varierande hastighet, byte at körfält samt körning på väg med varierandetopologi. En bromsalgoritm var även implementerad för att se till attbromsarna används sparsamt men effektivt. Resultatet blev att båda regulatorernaförsäkrade att lastbilen kan minimera felet i hastighet och position, medett största fel på 1m i position och 0.5m i hastighet i alla test. Regulatorernavar även robusta mot laterella förändringar samt utomstående krafter.
Place, publisher, year, edition, pages
2019. , p. 56
Series
TRITA-EECS-EX ; 2019:522
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:kth:diva-261709OAI: oai:DiVA.org:kth-261709DiVA, id: diva2:1359812
External cooperation
Scania AB
Educational program
Master of Science in Engineering - Electrical Engineering
Supervisors
Examiners
2019-10-102019-10-102022-06-26Bibliographically approved