Autonomous Vehicle Maneuvering at the Limit of Friction

Autonomous Vehicle Maneuvering at the Limit of Friction
Author :
Publisher : Linköping University Electronic Press
Total Pages : 75
Release :
ISBN-10 : 9789179297701
ISBN-13 : 9179297706
Rating : 4/5 (706 Downloads)

Book Synopsis Autonomous Vehicle Maneuvering at the Limit of Friction by : Victor Fors

Download or read book Autonomous Vehicle Maneuvering at the Limit of Friction written by Victor Fors and published by Linköping University Electronic Press. This book was released on 2020-10-23 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Without a driver to fall back on, a fully self-driving car needs to be able to handle any situation it can encounter. With the perspective of future safety systems, this research studies autonomous maneuvering at the tire-road friction limit. In these situations, the dynamics is highly nonlinear, and the tire-road parameters are uncertain. To gain insights into the optimal behavior of autonomous safety-critical maneuvers, they are analyzed using optimal control. Since analytical solutions of the studied optimal control problems are intractable, they are solved numerically. An optimization formulation reveals how the optimal behavior is influenced by the total amount of braking. By studying how the optimal trajectory relates to the attainable forces throughout a maneuver, it is found that maximizing the force in a certain direction is important. This is like the analytical solutions obtained for friction-limited particle models in earlier research, and it is shown to result in vehicle behavior close to the optimal also for a more complex model. Based on the insights gained from the optimal behavior, controllers for autonomous safety maneuvers are developed. These controllers are based on using acceleration-vector references obtained from friction-limited particle models. Exploiting that the individual tire forces tend to be close to their friction limits, the desired tire slip angles are determined for a given acceleration-vector reference. This results in controllers capable of operating at the limit of friction at a low computational cost and reduces the number of vehicle parameters used. For straight-line braking, ABS can intervene to reduce the braking distance without prior information about the road friction. Inspired by this, a controller that uses the available actuation according to the least friction necessary to avoid a collision is developed, resulting in autonomous collision avoidance without any estimation of the tire–road friction. Investigating time-optimal lane changes, it is found that a simple friction-limited particle model is insufficient to determine the desired acceleration vector, but including a jerk limit to account for the yaw dynamics is sufficient. To enable a tradeoff between braking and avoidance with a more general obstacle representation, the acceleration-vector reference is computed in a receding-horizon framework. The controllers developed in this thesis show great promise with low computational cost and performance not far from that obtained offline by using numerical optimization when evaluated in high-fidelity simulation.


Autonomous Vehicle Maneuvering at the Limit of Friction Related Books

Autonomous Vehicle Maneuvering at the Limit of Friction
Language: en
Pages: 75
Authors: Victor Fors
Categories:
Type: BOOK - Published: 2020-10-23 - Publisher: Linköping University Electronic Press

GET EBOOK

Without a driver to fall back on, a fully self-driving car needs to be able to handle any situation it can encounter. With the perspective of future safety syst
Trajectory Planning of an Autonomous Vehicle in Multi-Vehicle Traffic Scenarios
Language: en
Pages: 44
Authors: Mahdi Morsali
Categories:
Type: BOOK - Published: 2021-03-25 - Publisher: Linköping University Electronic Press

GET EBOOK

Tremendous industrial and academic progress and investments have been made in au-tonomous driving, but still many aspects are unknown and require further invest
Proceedings of Mechanical Engineering Research Day 2020
Language: en
Pages: 414
Authors: Mohd Fadzli Bin Abdollah
Categories: Technology & Engineering
Type: BOOK - Published: 2020-12-01 - Publisher: Centre for Advanced Research on Energy

GET EBOOK

This e-book is a compilation of 170 articles presented at the 7th Mechanical Engineering Research Day (MERD'20) - Kampus Teknologi UTeM (virtual), Melaka, Malay
Dynamics of Vehicles on Roads and Tracks
Language: en
Pages: 1421
Authors: Maksym Spiryagin
Categories: Technology & Engineering
Type: BOOK - Published: 2021-03-18 - Publisher: CRC Press

GET EBOOK

The International Symposium on Dynamics of Vehicles on Roads and Tracks is the leading international gathering of scientists and engineers from academia and ind
Dynamics of Vehicles on Roads and Tracks Vol 1
Language: en
Pages: 543
Authors: Maksym Spiryagin
Categories: Technology & Engineering
Type: BOOK - Published: 2017-12-06 - Publisher: CRC Press

GET EBOOK

The International Symposium on Dynamics of Vehicles on Roads and Tracks is the leading international gathering of scientists and engineers from academia and ind