84 citations · 464 across the 36 of their papers we have counts for
39 papers
Koopman Representation of Nonlinear Virtual Environments in Kinesthetic Haptic Systems
Yanting Zhou, Jozsef Kövecses, James Richard Forbes
Rendering haptic feedback with nonlinear virtual environments (VEs) is important in many applications that require highly accurate force feedback. This paper considers the use of t…
Laser-to-Vehicle Extrinsic Calibration in Low-Observability Scenarios for Subsea Mapping
Thomas Hitchcox, James Richard Forbes
Laser line scanners are increasingly being used in the subsea industry for high-resolution mapping and infrastructure inspection. However, calibrating the 3D pose of the scanner re…
Navigation and Control of Unconventional VTOL UAVs in Forward-Flight with Explicit Wind Velocity Estimation
Mitchell Cohen, James Richard Forbes
This paper presents a solution for the state estimation and control problems for a class of unconventional vertical takeoff and landing (VTOL) UAVs operating in forward-flight cond…
The Invariant Rauch-Tung-Striebel Smoother
Niels van der Laan, Mitchell Cohen, Jonathan Arsenault +1
This paper presents an invariant Rauch-Tung- Striebel (IRTS) smoother applicable to systems with states that are an element of a matrix Lie group. In particular, the extended Rauch…
Combining DVL-INS and Laser-Based Loop Closures in a Batch Estimation Framework for Underwater Positioning
Amro Al-Baali, Thomas Hitchcox, James Richard Forbes
Correcting gradual position drift is a challenge in long-term subsea navigation. Though highly accurate, modern inertial navigation system (INS) estimates will drift over time due…
Synthesizing Control Laws from Data using Sum-of-Squares Optimization
Jason J. Bramburger, Steven Dahdah, James Richard Forbes
The control Lyapunov function (CLF) approach to nonlinear control design is well established. Moreover, when the plant is control affine and polynomial, sum-of-squares (SOS) optimi…
Cascaded Model Predictive Control of a Tandem-Rotor Helicopter
Faraaz Ahmed, Ludwik Sobiesiak, James Richard Forbes
This letter considers cascaded model predictive control (MPC) as a computationally lightweight method for controlling a tandem-rotor helicopter. A traditional single MPC structure…
An Adaptive Graduated Nonconvexity Loss Function for Robust Nonlinear Least Squares Solutions
Kyungmin Jung, Thomas Hitchcox, James Richard Forbes
Many problems in robotics, such as estimating the state from noisy sensor data or aligning two point clouds, can be posed and solved as least-squares problems. Unfortunately, vanil…
Decentralized State Estimation: An Approach using Pseudomeasurements and Preintegration
Charles Champagne Cossette, Mohammed Ayman Shalaby, David Saussié +1
This paper addresses the problem of decentralized, collaborative state estimation in robotic teams. In particular, this paper considers problems where individual robots estimate si…
Multi-Robot Relative Pose Estimation and IMU Preintegration Using Passive UWB Transceivers
Mohammed Ayman Shalaby, Charles Champagne Cossette, Jerome Le Ny +1
Ultra-wideband (UWB) systems are becoming increasingly popular as a means of inter-robot ranging and communication. A major constraint associated with UWB is that only one pair of…
Closed-Loop Koopman Operator Approximation
Steven Dahdah, James Richard Forbes
This paper proposes a method to identify a Koopman model of a feedback-controlled system given a known controller. The Koopman operator allows a nonlinear system to be rewritten as…
Improving Self-Consistency in Underwater Mapping Through Laser-Based Loop Closure (Extended)
Thomas Hitchcox, James Richard Forbes
Accurate, self-consistent bathymetric maps are needed to monitor changes in subsea environments and infrastructure. These maps are increasingly collected by underwater vehicles, an…
Know What You Don't Know: Consistency in Sliding Window Filtering with Unobservable States Applied to Visual-Inertial SLAM (Extended Version)
Daniil Lisus, Mitchell Cohen, James Richard Forbes
Estimation algorithms, such as the sliding window filter, produce an estimate and uncertainty of desired states. This task becomes challenging when the problem involves unobservabl…
Reducing Two-Way Ranging Variance by Signal-Timing Optimization
Mohammed Ayman Shalaby, Charles Champagne Cossette, James Richard Forbes +1
Time-of-flight-based ranging among transceivers with different clocks requires protocols that accommodate varying rates of the clocks. Double-sided two-way ranging (DS-TWR) is wide…
Calibration and Uncertainty Characterization for Ultra-Wideband Two-Way-Ranging Measurements
Mohammed Ayman Shalaby, Charles Champagne Cossette, James Richard Forbes +1
Ultra-Wideband (UWB) systems are becoming increasingly popular for indoor localization, where range measurements are obtained by measuring the time-of-flight of radio signals. Howe…
Performance Evaluation of 3D Keypoint Detectors and Descriptors on Coloured Point Clouds in Subsea Environments
Kyungmin Jung, Thomas Hitchcox, James Richard Forbes
The recent development of high-precision subsea optical scanners allows for 3D keypoint detectors and feature descriptors to be leveraged on point cloud scans from subsea environme…
System Identification and Two-Degree-of-Freedom Control of Nonlinear, Viscoelastic Tissues
Amanda Bianco, Raphael Zonis, Anne-Marie Lauzon +2
Objective: This paper presents a force control scheme for brief isotonic holds in an isometrically contracted muscle tissue, with minimal overshoot and settling time to measure its…
Relative Position Estimation in Multi-Agent Systems Using Attitude-Coupled Range Measurements
Mohammed Shalaby, Charles Champagne Cossette, James Richard Forbes +1
The ability to accurately estimate the position of robotic agents relative to one another, in possibly GPS-denied environments, is crucial to execute collaborative tasks. Inter-age…
Model Predictive Control of a Tandem-Rotor Helicopter With a Nonuniformly Spaced Prediction Horizon
Faraaz Ahmed, Ludwik Sobiesiak, James Richard Forbes
This letter considers model predictive control of a tandem-rotor helicopter. The error is formulated using the matrix Lie group . A reference trajectory to a target is cal…
Mind the Gap: Norm-Aware Adaptive Robust Loss for Multivariate Least-Squares Problems
Thomas Hitchcox, James Richard Forbes
Measurement outliers are unavoidable when solving real-world robot state estimation problems. A large family of robust loss functions (RLFs) exists to mitigate the effects of outli…
Optimal Multi-robot Formations for Relative Pose Estimation Using Range Measurements
Charles Champagne Cossette, Mohammed Ayman Shalaby, David Saussie +2
In multi-robot missions, relative position and attitude information between agents is valuable for a variety of tasks such as mapping, planning, and formation control. In this pape…
Ultra-Wideband Teach and Repeat
Mohammed Ayman Shalaby, Charles Champagne Cossette, Jerome Le Ny +1
Autonomously retracing a manually-taught path is desirable for many applications, and Teach and Repeat (T&R) algorithms present an approach that is suitable for long-range autonomy…
System Norm Regularization Methods for Koopman Operator Approximation
Steven Dahdah, James Richard Forbes
Approximating the Koopman operator from data is numerically challenging when many lifting functions are considered. Even low-dimensional systems can yield unstable or ill-condition…
Localization with Directional Coordinates
Charles Champagne Cossette, Mohammed Shalaby, David Saussié +1
A coordinate system is proposed that replaces the usual three-dimensional Cartesian x,y,z position coordinates, for use in robotic localization applications. Range, azimuth, and el…