Modelling and Navigation of Autonomous Vehicles on Roundabouts
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Date
2021-01-08
Authors
Mandyam, Dave
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
A path following controller was proposed that allows autonomous vehicles to safely navigate
roundabouts. The controller consisted of a vector field algorithm that generated velocity
commands to direct a vehicle. These velocity commands were fulfilled by an actuator
controller that converts the velocity commands into wheel torques and steering angles that
physically move a vehicle. This conversion is accomplished using an online optimization
process that relies on an internal vehicle model to solve for necessary wheel torques and
steering angles.
To test the controller’s performance, a 16 degree of freedom vehicle dynamic model was
developed with consideration for vehicle turn physics. Firstly, tire force data was gathered by
performing driving maneuvers on a test track using a vehicle fitted with tire measurement
equipment. The generated tire force data was used to compare various combined slip tire force
models for their accuracy. The most accurate model was added to the high-fidelity vehicle
model. Next, suspension kinematic data was generated using a simple testing procedure. The
vehicle was equipped with the tire measurement equipment and the vehicle was raised a
lowered with a hydraulic jack. Using displacement and orientation data from this test, a novel
reduced order suspension kinematic model that reproduces the observed motion profile was
developed.
Application of the path following controller to the high-fidelity model resulted in close
following of a roundabout path with small deviations.
Description
Keywords
Vehicle Dynamics, Tire Modelling, Path Following, Roundabouts, Suspension Kinematics
LC Keywords
Automated vehicles, Traffic circles, Automobiles, Tires, Springs and suspension, Testing, Lasers in navigation