ONLINE SYSTEM IDENTIFICATION AND CONTROL OF AN AUTONOMOUS UNDERWATER VEHICLE

Ph.DDOCTOR OF PHILOSOPH

Autonomous Personal Mobility Scooter for Multi-Class Mobility-On-Demand Service

In this paper, we describe the design and development of an autonomous personal mobility scooter that was used in public trials during the 2016 MIT Open House, for the purpose of raising public awareness and interest about autonomous vehicles. The scooter is intended to work cooperatively with other classes of autonomous vehicles such as road cars and golf cars to improve the efficacy of Mobility-on-Demand transportation solutions. The scooter is designed to be robust, reliable, and safe, while operating under prolonged durations. The flexibility in fleet expansion is shown by replicating the system architecture and sensor package that has been previously implemented in the road car and golf cars. We show that the vehicle performed robustly with small localization variance. A survey of the users shows that the public is very receptive to the concept of the autonomous personal mobility device.Singapore-MIT Alliance for Research and Technology (SMART) (Future Urban Mobility research program)Singapore. National Research Foundatio

MoS 2 and WS 2 nanocone arrays: Impact of surface topography on the hydrogen evolution electrocatalytic activity and mass transport

We report the fabrication and electrochemical study of edge-abundant transition metal dichalcogenide (TMD) nanocone arrays. Time-dependent etching by sequential use of isotropic O2 and anisotropic SF6/C4F8 plasmas on nanosphere monolayer-modified TMD crystals results in very high coverage nanocone array structures with tunable aspect ratios and interspacings. Electrochemical characterization of these arrays via the hydrogen evolution reaction (HER), using a low proton concentration electrolyte (2 mM HClO4, 0.1 M NaClO4) to reveal morphology-dependent mass transport features at the proton diffusion-controlled region, show significant changes in electrocatalytic behaviour at both WS2 and MoS2: notably onset potential shifts of 100 and 200 mV, and Tafel slope decreases of 50 and 120 mV dec−1 respectively. These improvements vary according to the geometry of the arrays and the availability of catalytic edge sites, and thus the observed electrochemical behaviour can be rationalized via kinetic and mass transport effects

Hydrodynamic modelling and identification of the robotics research centre remotely operated vehicle mark II

Dynamics model is essential and critical for a successful navigation and control system design of an underwater vehicle. The main difficulty in dynamics modelling of an underwater vehicle is due to the hydrodynamics forces, in which added mass coefficients and drag coefficients need to be determined. In this project, two approaches computational fluid dynamics (CFD) approach and experimental approach have been used to find the hydrodynamics coefficients for the RRC ROV II, a remotely operated underwater vehicle. Under the CFD approach, WAMIT and ANSYS CFX have been used to estimate added mass coefficients and drag coefficients respectively. After that, the coefficients were compared with the experimental result obtained from a novel free decay test of a scaled model of ROV II. The results show good agreement in prediction of both added mass and drag coefficients. The usage of experimental method and CFD method in parallel has suggested that the two methods complement each other and one's advantages could be used to mask another's weaknesses. The hydrodynamics coefficients found have been verified through experiments using physical ROV II. Therefore, the combined approach developed in this report could be used to find the added mass and drag coefficients for other underwater vehicles.MASTER OF ENGINEERING (MAE

Roll control of an autonomous underwater vehicle using an internal rolling mass

10.1007/978-3-319-07488-7_16Springer Tracts in Advanced Robotics105229-24

Connected Cooperative Control of Autonomous Vehicles During Unexpected Road Situations

This article discusses how connected cooperative control of autonomous vehicles (AVs) can help in providing safe and comfortable mobility during unexpected road situations. Driving AVs in urban areas poses a big challenge due to the complexity of the traffic rules as well as unexpected scenarios involved. In these situations, an inter-vehicle communication system can be of great help. Cooperation between multiple AVs is possible with the development of vehicular communication. In particular, state estimation can be improved with multiple sources of information gathered from different vehicles. Cooperative state estimation can also improve robustness against communication failure. With future trajectories shared among nearby vehicles, the motion can be coordinated to make navigation safer and smoother for AVs. For vehicular communication, the IEEE 802.11p standard has been designed to allow information exchange between high-speed cars, and between vehicles and roadside infrastructure. Other wireless communication technologies, such as 3G, 4G, and WiFi, are also suggested.</jats:p

Perception, Planning, Control, and Coordination for Autonomous Vehicles

Autonomous vehicles are expected to play a key role in the future of urban transportation systems, as they offer potential for additional safety, increased productivity, greater accessibility, better road efficiency, and positive impact on the environment. Research in autonomous systems has seen dramatic advances in recent years, due to the increases in available computing power and reduced cost in sensing and computing technologies, resulting in maturing technological readiness level of fully autonomous vehicles. The objective of this paper is to provide a general overview of the recent developments in the realm of autonomous vehicle software systems. Fundamental components of autonomous vehicle software are reviewed, and recent developments in each area are discussed. Keywords: autonomous vehicles; localization; perception; planning; automotive control; multi-vehicle cooperatio

Tunable quantum switch realized with a single Λ-level atom coupled to the microtoroidal cavity

We propose a realization of the quantum switch for coherent light fields for the fiber-coupled microdisk cavities. We demonstrate by combining numerical and analytical methods that both in strong coupling and bad cavity limits it is possible to change a system's behavior from being fully transparent to being fully reflective by varying the amplitude of the external control field. We remark that tuning the amplitude of the control field instead of cavity-atom coupling strength, which was suggested by S. Parkins et al., [Phys. Rev. A 90, 053822 (2014)] for two-level atoms and works only in the strong coupling limit, brings more control and tunability over the transmitted and reflected intensities. We also demonstrate the possibility of controlling the statistics of the input coherent field with the control field which opens the venue for obtaining quantum states of light.NRF (Natl Research Foundation, S’pore)ASTAR (Agency for Sci., Tech. and Research, S’pore)Published versio

Trajectory optimization for autonomous overtaking with visibility maximization

© 2017 IEEE. In this paper we present a trajectory generation method for autonomous overtaking of static obstacles in a dynamic urban environment. In these settings, blind spots can arise from perception limitations. For example, the autonomous car may have to move slightly into the opposite lane in order to cleanly see in front of a car ahead. Once it has gathered enough information about the road ahead, then the autonomous car can safely overtake. We generate safe trajectories by solving, in real-time, a non-linear constrained optimization, formulated as a Receding Horizon planner. The planner is guided by a high-level state machine, which determines when the overtake maneuver should begin. Our main contribution is a method that can maximize visibility, prioritizes safety and respects the boundaries of the road while executing the maneuver. We present experimental results in simulation with data collected during real driving