Publications
Publication list under construction
Published in The International Journal of Robotics Research, 2024
Abstract: We present novel, convex relaxations for rotation and pose estimation problems that can a posteriori guarantee global optimality for practical measurement noise levels. Some such relaxations exist in the literature for specific problem setups that assume the matrix von Mises-Fisher distribution (a.k.a., matrix Langevin distribution or chordal distance) for... Read more
Recommended citation: Timothy Barfoot, Connor Holmes, Frederike D{\"u}mbgen, "Certifiably Optimal Rotation and Pose Estimation Based on the Cayley Map." The International Journal of Robotics Research, 2024.
Published in arXiv:2406.02365, 2024
Abstract: In recent years, many estimation problems in robotics have been shown to be solvable to global optimality using their semidefinite relaxations. However, the runtime complexity of off-the-shelve semidefinite programming solvers is up to cubic in problem size, which inhibits real-time solutions of problems involving large state dimensions. We show... Read more
Recommended citation: Frederike D{\"u}mbgen, Connor Holmes, Timothy Barfoot, "Exploiting Chordal Sparsity for Fast Global Optimality with Application to Localization." arXiv:2406.02365, 2024.
Published in arXiv:2405.19309, 2024
Abstract: Differentiable optimization is a powerful new paradigm capable of reconciling model-based and learning-based approaches in robotics. However, the majority of robotics optimization problems are non-convex and current differentiable optimization techniques are therefore prone to convergence to local minima. When this occurs, the gradients provided by these existing solvers can... Read more
Recommended citation: Connor Holmes, Frederike D{\"u}mbgen, Timothy Barfoot, "SDPRLayers: Certifiable Backpropagation Through Polynomial Optimization Problems in Robotics." arXiv:2405.19309, 2024.
Published in IEEE Transactions on Robotics, 2024
Abstract: In recent years, semidefinite relaxations of common optimization problems in robotics have attracted growing attention due to their ability to provide globally optimal solutions. In many cases, it was shown that specific handcrafted redundant constraints are required to obtain tight relaxations, and thus global optimality. These constraints are formulation-dependent... Read more
Recommended citation: Frederike D{\"u}mbgen, Connor Holmes, Ben Agro, Timothy Barfoot, "Toward Globally Optimal State Estimation Using Automatically Tightened Semidefinite Relaxations." IEEE Transactions on Robotics, 2024.
Published in IEEE Transactions on Robotics, 2024
Abstract: In recent years, there has been remarkable progress in the development of so-called certifiable perception methods, which leverage semidefinite, convex relaxations to find global optima of perception problems in robotics. However, many of these relaxations rely on simplifying assumptions that facilitate the problem formulation, such as an isotropic measurement... Read more
Recommended citation: Connor Holmes, Frederike D{\"u}mbgen, Timothy Barfoot, "On Semidefinite Relaxations for Matrix-Weighted State-Estimation Problems in Robotics." IEEE Transactions on Robotics, 2024.
Published in IEEE Robot. Autom. Lett., 2023
Abstract: Modern state estimation is often formulated as an optimization problem and solved using efficient local search methods. These methods at best guarantee convergence to local minima, but, in some cases, global optimality can also be certified. Although such global optimality certificates have been well established for 3D pose-graph optimization,... Read more
Recommended citation: Connor Holmes, Timothy Barfoot, "An Efficient Global Optimality Certificate for Landmark-Based SLAM." IEEE Robot. Autom. Lett., 2023.
Published in IEEE Robotics and Automation Letters, 2023
Abstract: A common approach to localize a mobile robot is by measuring distances to points of known positions, called anchors. Locating a device from distance measurements is typically posed as a non-convex optimization problem, stemming from the nonlinearity of the measurement model. Non-convex optimization problems may yield suboptimal solutions when... Read more
Recommended citation: Frederike D{\"u}mbgen, Connor Holmes, Timothy Barfoot, "Safe and Smooth: Certified Continuous-Time Range-Only Localization." IEEE Robotics and Automation Letters, 2023.
Published in In the proceedings of 2023 20th Conference on Robots and Vision (CRV), 2023
Use Google Scholar for full citation Read more
Recommended citation: Daniil Lisus, Connor Holmes, Steven Waslander, "Towards Open World Nerf-Based Slam." In the proceedings of 2023 20th Conference on Robots and Vision (CRV), 2023.
Published in arXiv:2206.05082, 2022
Abstract: This note uses the Total Least-Squares (TLS) line-fitting problem as a canvas to explore some modern optimization tools. The contribution is meant to be tutorial in nature. The TLS problem has a lot of mathematical similarities to important problems in robotics and computer vision but is easier to visualize... Read more
Recommended citation: Timothy Barfoot, Connor Holmes, Frederike Dumbgen, "A Fine Line: Total Least-Squares Line Fitting as QCQP Optimization." arXiv:2206.05082, 2022.
Published in Frontiers in Robotics and AI, 2021
Abstract: Low frequency dynamics introduced by structural flexibility can result in considerable performance degradation and even instability in on-orbit, robotic manipulators. Although there is a wealth of literature that addresses this problem, the author has found that many advanced solutions are often precluded by practical considerations. On the other hand,... Read more
Recommended citation: Connor Holmes, "Practical Design Considerations for Performance and Robustness in the Face of Uncertain Flexible Dynamics in Space Manipulators." Frontiers in Robotics and AI, 2021.
Published in In the proceedings of 2016 American Control Conference (ACC), 2016
Abstract: A method to characterize the symmetries inherent within physical systems via automorphism groups has already been established. In this paper, we define a specific block diagonal form to which a matrix can be decomposed if and only if it conforms with a given set of symmetries. We employ this... Read more
Recommended citation: Connor Holmes, Mireille Broucke, "Pattern Preserving Pole Placement and Stabilization for Linear Systems." In the proceedings of 2016 American Control Conference (ACC), 2016.
Published in In the proceedings of 2014 IEEE 15th Workshop on Control and Modeling for Power Electronics (COMPEL), 2014
Abstract: This paper presents the first dynamic model of the DC-MMC, a new class of modular multilevel single-stage dc/dc converters aptly suited for HVDC systems. A state-space model for a single string of the DC-MMC is developed and validated by comparing with time-domain simulation results from a comprehensive switched converter... Read more
Recommended citation: Gregory Kish, Connor Holmes, Peter Lehn, "Dynamic Modeling of Modular Multilevel DC/DC Converters for HVDC Systems." In the proceedings of 2014 IEEE 15th Workshop on Control and Modeling for Power Electronics (COMPEL), 2014.
You can also find my articles on my Google Scholar profile.
