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Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control

Vehicle safety remains an important topic in the automotive industry due to the large number of vehicle accidents each year. One of the causes of vehicle accidents is due to vehicle instability phenomena. Vehicle instability can occur due to unexpected road profile changes, during full braking, obst...

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Main Author: Gwayi, Isaac
Other Authors: Tsoeu, Mohohlo S.
Format: Thesis
Language:English
Published: Department of Electrical Engineering 2019
Subjects:
Engineering
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access_status_str Open Access
author Gwayi, Isaac
author2 Tsoeu, Mohohlo S.
author_browse Gwayi, Isaac
Tsoeu, Mohohlo S.
author_facet Tsoeu, Mohohlo S.
Gwayi, Isaac
author_sort Gwayi, Isaac
collection Thesis
description Vehicle safety remains an important topic in the automotive industry due to the large number of vehicle accidents each year. One of the causes of vehicle accidents is due to vehicle instability phenomena. Vehicle instability can occur due to unexpected road profile changes, during full braking, obstacle avoidance or severe manoeuvring. Three main instability phenomena can be distinguished: the yaw-rate instability, the rollover and the jack-knife phenomenon. The main goal of this study is to develop a yaw-rate and rollover stability controller of an Autonomous Scaled Ground Vehicle (ASGV) using Nonlinear Model Predictive Control (NMPC). Open Source Software (OSS) known as Automatic Control and Dynamic Optimisation (ACADO) is used to design and simulate the NMPC controller based on an eight Degree of Freedom (8 DOF) nonlinear vehicle model with Pacejka tire model. Vehicle stability limit were determined using load transfer ratio (LTR). Double lane change (DLC) steering manoeuvres were used to calculate the LTR. The simulation results show that the designed NMPC controller is able to track a given trajectory while preventing the vehicle from rolling over and spinning out by respecting given constraints. A maximum trajectory tracking error of 0.1 meters (on average) is reported. To test robustness of the designed NMPC controller to model mismatch, four simulation scenarios are done. Simulation results show that the controller is robust to model mismatch. To test disturbance rejection capability of the controller, two simulations are performed, with pulse disturbances of 0.02 radians and 0.05 radians. Simulations results show that the controller is able to reject the 0.02 radians disturbance. The controller is not able to reject the 0.05 radians disturbance.
format Thesis
id oai:open.uct.ac.za:11427/30054
institution University of Cape Town (South Africa)
language eng
last_indexed 2026-06-10T12:32:07.214Z
license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2019
publishDateRange 2019
publishDateSort 2019
publisher Department of Electrical Engineering
publisherStr Department of Electrical Engineering
record_format dspace
source_str UCTD — University of Cape Town Open Access Repository
spelling oai:open.uct.ac.za:11427/30054 Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control Gwayi, Isaac Tsoeu, Mohohlo S. Engineering Vehicle safety remains an important topic in the automotive industry due to the large number of vehicle accidents each year. One of the causes of vehicle accidents is due to vehicle instability phenomena. Vehicle instability can occur due to unexpected road profile changes, during full braking, obstacle avoidance or severe manoeuvring. Three main instability phenomena can be distinguished: the yaw-rate instability, the rollover and the jack-knife phenomenon. The main goal of this study is to develop a yaw-rate and rollover stability controller of an Autonomous Scaled Ground Vehicle (ASGV) using Nonlinear Model Predictive Control (NMPC). Open Source Software (OSS) known as Automatic Control and Dynamic Optimisation (ACADO) is used to design and simulate the NMPC controller based on an eight Degree of Freedom (8 DOF) nonlinear vehicle model with Pacejka tire model. Vehicle stability limit were determined using load transfer ratio (LTR). Double lane change (DLC) steering manoeuvres were used to calculate the LTR. The simulation results show that the designed NMPC controller is able to track a given trajectory while preventing the vehicle from rolling over and spinning out by respecting given constraints. A maximum trajectory tracking error of 0.1 meters (on average) is reported. To test robustness of the designed NMPC controller to model mismatch, four simulation scenarios are done. Simulation results show that the controller is robust to model mismatch. To test disturbance rejection capability of the controller, two simulations are performed, with pulse disturbances of 0.02 radians and 0.05 radians. Simulations results show that the controller is able to reject the 0.02 radians disturbance. The controller is not able to reject the 0.05 radians disturbance. 2019-05-10T12:11:15Z 2019-05-10T12:11:15Z 2018 2019-05-07T09:16:37Z Master Thesis Masters MSc (Engineering) http://hdl.handle.net/11427/30054 eng application/pdf Department of Electrical Engineering Faculty of Engineering and the Built Environment
spellingShingle Engineering
Gwayi, Isaac
Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control
thesis_degree_str Master's
title Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control
title_full Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control
title_fullStr Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control
title_full_unstemmed Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control
title_short Rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control
title_sort rollover prevention and path following of a scaled autonomous vehicle using nonlinear model predictive control
topic Engineering
url http://hdl.handle.net/11427/30054
work_keys_str_mv AT gwayiisaac rolloverpreventionandpathfollowingofascaledautonomousvehicleusingnonlinearmodelpredictivecontrol

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