31 research outputs found
Pre-Deployment Testing of Low Speed, Urban Road Autonomous Driving in a Simulated Environment
Low speed autonomous shuttles emulating SAE Level L4 automated driving using
human driver assisted autonomy have been operating in geo-fenced areas in
several cities in the US and the rest of the world. These autonomous vehicles
(AV) are operated by small to mid-sized technology companies that do not have
the resources of automotive OEMs for carrying out exhaustive, comprehensive
testing of their AV technology solutions before public road deployment. Due to
the low speed of operation and hence not operating on roads containing
highways, the base vehicles of these AV shuttles are not required to go through
rigorous certification tests. The way the driver assisted AV technology is
tested and allowed for public road deployment is continuously evolving but is
not standardized and shows differences between the different states where these
vehicles operate. Currently, AVs and AV shuttles deployed on public roads are
using these deployments for testing and improving their technology. However,
this is not the right approach. Safe and extensive testing in a lab and
controlled test environment including Model-in-the-Loop (MiL),
Hardware-in-the-Loop (HiL) and Autonomous-Vehicle-in-the-Loop (AViL) testing
should be the prerequisite to such public road deployments. This paper presents
three dimensional virtual modeling of an AV shuttle deployment site and
simulation testing in this virtual environment. We have two deployment sites in
Columbus of these AV shuttles through the Department of Transportation funded
Smart City Challenge project named Smart Columbus. The Linden residential area
AV shuttle deployment site of Smart Columbus is used as the specific example
for illustrating the AV testing method proposed in this paper
Discrete-time Robust PD Controlled System with DOB/CDOB Compensation for High Speed Autonomous Vehicle Path Following
Autonomous vehicle path following performance is one of significant
consideration. This paper presents discrete time design of robust PD controlled
system with disturbance observer (DOB) and communication disturbance observer
(CDOB) compensation to enhance autonomous vehicle path following performance.
Although always implemented on digital devices, DOB and CDOB structure are
usually designed in continuous time in the literature and also in our previous
work. However, it requires high sampling rate for continuous-time design block
diagram to automatically convert to corresponding discrete-time controller
using rapid controller prototyping systems. In this paper, direct discrete time
design is carried out. Digital PD feedback controller is designed based on the
nominal plant using the proposed parameter space approach. Zero order hold
method is applied to discretize the nominal plant, DOB and CDOB structure in
continuous domain. Discrete time DOB is embedded into the steering to path
following error loop for model regulation in the presence of uncertainty in
vehicle parameters such as vehicle mass, vehicle speed and road-tire friction
coefficient and rejecting external disturbance like crosswind force. On the
other hand, time delay from CAN bus based sensor and actuator command
interfaces results in degradation of system performance since large negative
phase angles are added to the plant frequency response. Discrete time CDOB
compensated control system can be used for time delay compensation where the
accurate knowledge of delay time value is not necessary. A validated model of
our lab Ford Fusion hybrid automated driving research vehicle is used for the
simulation analysis while the vehicle is driving at high speed. Simulation
results successfully demonstrate the improvement of autonomous vehicle path
following performance with the proposed discrete time DOB and CDOB structure
Cooperative Collision Avoidance in a Connected Vehicle Environment
Connected vehicle (CV) technology is among the most heavily researched areas
in both the academia and industry. The vehicle to vehicle (V2V), vehicle to
infrastructure (V2I) and vehicle to pedestrian (V2P) communication capabilities
enable critical situational awareness. In some cases, these vehicle
communication safety capabilities can overcome the shortcomings of other sensor
safety capabilities because of external conditions such as 'No Line of Sight'
(NLOS) or very harsh weather conditions. Connected vehicles will help cities
and states reduce traffic congestion, improve fuel efficiency and improve the
safety of the vehicles and pedestrians. On the road, cars will be able to
communicate with one another, automatically transmitting data such as speed,
position, and direction, and send alerts to each other if a crash seems
imminent. The main focus of this paper is the implementation of Cooperative
Collision Avoidance (CCA) for connected vehicles. It leverages the Vehicle to
Everything (V2X) communication technology to create a real-time implementable
collision avoidance algorithm along with decision-making for a vehicle that
communicates with other vehicles. Four distinct collision risk environments are
simulated on a cost effective Connected Autonomous Vehicle (CAV) Hardware in
the Loop (HIL) simulator to test the overall algorithm in real-time with real
electronic control and communication hardware
Customized Co-Simulation Environment for Autonomous Driving Algorithm Development and Evaluation
Increasing the implemented SAE level of autonomy in road vehicles requires
extensive simulations and verifications in a realistic simulation environment
before proving ground and public road testing. The level of detail in the
simulation environment helps ensure the safety of a real-world implementation
and reduces algorithm development cost by allowing developers to complete most
of the validation in the simulation environment. Considering sensors like
camera, LIDAR, radar, and V2X used in autonomous vehicles, it is essential to
create a simulation environment that can provide these sensor simulations as
realistically as possible. While sensor simulations are of crucial importance
for perception algorithm development, the simulation environment will be
incomplete for the simulation of holistic AV operation without being
complemented by a realistic vehicle dynamic model and traffic cosimulation.
Therefore, this paper investigates existing simulation environments, identifies
use case scenarios, and creates a cosimulation environment to satisfy the
simulation requirements for autonomous driving function development using the
Carla simulator based on the Unreal game engine for the environment, Sumo or
Vissim for traffic co-simulation, Carsim or Matlab, Simulink for vehicle
dynamics co-simulation and Autoware or the author or user routines for
autonomous driving algorithm co-simulation. As a result of this work, a
model-based vehicle dynamics simulation with realistic sensor simulation and
traffic simulation is presented. A sensor fusion methodology is implemented in
the created simulation environment as a use case scenario. The results of this
work will be a valuable resource for researchers who need a comprehensive
co-simulation environment to develop connected and autonomous driving
algorithms
Impact of Different Desired Velocity Profiles and Controller Gains on Convoy Driveability of Cooperative Adaptive Cruise Control Operated Platoons
As the development of autonomous vehicles rapidly advances, the use of
convoying/platooning becomes a more widely explored technology option for
saving fuel and increasing the efficiency of traffic. In cooperative adaptive
cruise control (CACC), the vehicles in a convoy follow each other under
adaptive cruise control (ACC) that is augmented by the sharing of preceding
vehicle acceleration through the vehicle to vehicle communication in a
feedforward control path. In general, the desired velocity optimization for
vehicles in the convoy is based on fuel economy optimization, rather than
driveability. This paper is a preliminary study on the impact of the desired
velocity profile on the driveability characteristics of a convoy of vehicles
and the controller gain impact on the driveability. A simple low-level
longitudinal model of the vehicle has been used along with a PD type cruise
controller and a generic spacing policy for ACC/CACC. The acceleration of the
previous vehicle is available to the next vehicle as input, and the simulations
are performed as Cooperative Adaptive Cruise Control of a convoy of vehicles.
Individual vehicle acceleration profiles have been analyzed for driveability
for two different velocity profiles that are followed in a stretch of 720 m
between stop signs. The controller gains have been re-tuned based on the
parameter space robust control PID approach for driveability and compared with
the original gains. The US06 SFTP drive cycle has also been used for the
comparison of the two different controller gain sets
Greening the Greyfields
This open access book outlines new concepts, development models, governance and implementation processes capable of addressing the challenges of transformative urban regeneration of cities at precinct scale
Greening the Greyfields New Models for Regenerating the Middle Suburbs of Low-Density Cities
This open access book outlines new concepts, development models, governance and implementation processes capable of addressing the challenges of transformative urban regeneration of cities at precinct scale
Greening the Greyfields
This open access book outlines new concepts, development models, governance and implementation processes capable of addressing the challenges of transformative urban regeneration of cities at precinct scale
Investigating the current approach to developing data governance in the Canadian smart city
Smart cities have grown in prevalence as cities take advantage of big data and connected technologies to address the issues of sustainable urban development in the face of their growing urban populations. Data governance is necessary to smart cities to ensure integrity, accessibility, and accountability of data. There is also a growing concern about having proper data governance to protect citizens’ digital rights and democracy. Though these concerns are pressing, there is a gap in understanding the data governance strategies of city governments and the roles that they play in developing those strategies. Additionally, literature on smart cities often focuses on data privacy and security instead of discussing data governance comprehensively and does not discuss the role of the city. This thesis aims to address this gap by understanding the current state of data governance of proposed Canadian smart cities, through identifying their data governance decisions and classifying them into the roles they are adopting. The Smart Cities Challenge in Canada presented an opportunity to study proposed smart cities for their data governance decisions and the role of the city through content analysis, using concepts from Khatri and Brown’s (2010) data governance framework and Bayat and Kawalek’s (2018) model of data governance city roles. The analysis found that the proposed Canadian smart cities are planning to develop their smart city projects and data governance using an approach driven by open and collaborative principles. This open and collaborative approach adopted by the Canadian smart cities prioritizes data governance activities that address the data access, data principles, and data lifecycle decision domains, in conjunction to the cities taking on roles that emphasize transparency, co-creation, and high stakeholder involvement. Openness and collaboration are discussed to be critical to the success of smart cities, as they can drive mechanisms to help address the challenges of trust and achieve and maintain democratic accountability. This open and collaborative state of smart city data governance also supports a transformation of the smart city discourse, moving away from vendor-driven and citizen-driven smart cities and towards government-driven smart cities. The study outlines considerations for the proposed Canadian smart cities and their stakeholders to act on the gaps in their data governance strategies as identified in the results. Future smart cities are recommended to proactively use an open and collaborative approach in developing their smart city plans and data governance strategies