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Matthew Travers - IEEE Xplore Author Profile

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Autonomous robot navigation in complex environments requires robust perception as well as high-level scene understanding due to perceptual challenges, such as occlusions, and uncertainty introduced by robot movement. For example, a robot climbing a cluttered staircase can misinterpret clutter as a step, misrepresenting the state and compromising safety. This requires robust state estimation method...Show More
In this paper, we present a novel motion planning algorithm that inherits the strengths of both optimization and search-based planners. Optimization-based planners use the gradient of an objective function to generate a desired path, whereas search-based planners operate on a graph capturing the salient topology of a robot’s free space. A class of optimization-based planners leverages prior inform...Show More
Centralized control of a multi-agent system improves upon distributed control especially when multiple agents share a common task e.g., sorting different materials in a recycling facility. Traditionally, each agent in a sorting facility is tuned individually which leads to suboptimal performance if one agent is less efficient than the others. Centralized control overcomes this bottleneck by levera...Show More
Autonomous robot navigation in austere environments is critical to missions like “search and rescue”, yet it remains difficult to achieve. The recent DARPA Subterranean Challenge (SubT) highlights prominent challenges including GPS-denied navigation through rough terrains, rapid exploration in large-scale three-dimensional (3D) space, and interrobot coordination over unreliable communication. Solv...Show More
This paper presents polycarbonate negative topographies used as substrates for the templated selfassembly of microsphere-based microrobots. This approach protects primary structures from damage during molding and de-molding, providing high fidelity negatives of arrays for assembly via templated assembly by selective removal (TASR). We show that reducing the surface energy mismatch between the micr...Show More
Robotic systems need advanced mobility capabili-ties to operate in complex, three-dimensional environments designed for human use, e.g., multi-level buildings. Incorporating some level of autonomy enables robots to operate robustly, reliably, and efficiently in such complex environments, e.g., automatically “returning home” if communication between an operator and robot is lost during deployment. ...Show More
Modular robots can be rearranged into a new design, perhaps each day, to handle a wide variety of tasks by forming a customized robot for each new task. However, reconfiguring just the mechanism is not sufficient: each design also requires its own unique control policy. One could craft a policy from scratch for each new design, but such an approach is not scalable, especially given the large numbe...Show More
Effectively disassembling and recovering materials from waste electrical and electronic equipment (WEEE) is a critical step in moving global supply chains from carbon-intensive, mined materials to recycled and renewable ones. Conventional recycling processes rely on shredding and sorting waste streams, but for WEEE, which is comprised of numerous dissimilar materials, we explore targeted disassemb...Show More
The difficulty associated with the coordinated locomotion of legged robots grows quickly as the number of joints increases. Although prior approaches have addressed this problem through sampling-based planners, learning-based techniques have recently been explored as a means to handle such complexity. Among these recent approaches are systems that utilize probabilistic graphical models in order to...Show More
This paper presents two novel factor graph formulations for performing flow control on radio transceivers forming a large Wireless Mesh Network (WMN). Both factor graph formulations are abstractions of a discrete-time finite-horizon Linear Quadratic Regulator (LQR) used to solve an Optimal Control Problem (OCP). The first formulation, WMNLQR, is a centralized controller which demonstrates the supe...Show More
Methods for state estimation that rely on visual information are challenging on legged robots due to rapid changes in the viewing angle of onboard cameras. In this work, we show that by leveraging structure in the way that the robot locomotes, the accuracy of visual-inertial SLAM in these challenging scenarios can be increased. We present a method that takes advantage of the underlying periodic pr...Show More
Modular robots are made up of a set of components which can be configured and reconfigured to form customized robots for a wide range of tasks. Fully utilizing the flexibility of modular robots is challenging, as it requires the identification of optimal modular designs for each given task, often with limited computation and time. Previous works in design automation achieve efficient run-times by ...Show More
Snake robots composed of alternating single-axis pitch and yaw joints have many internal degrees of freedom, which make them capable of versatile three-dimensional locomotion. In motion planning process, snake robot motions are often designed kinematically by a chronological sequence of continuous backbone curves that capture desired macroscopic shapes of the robot. However, as the geometric arran...Show More
This work demonstrates a novel approach to steering a magnetic swimming robot in two dimensions with a single pair of Maxwell coils. By leveraging the curvature of the magnetic field gradient, we achieve motion along two axes. This method allows us to control medical magnetic robots using only existing MRI technology, without requiring additional hardware or posing any additional risk to the patie...Show More
Snake robots have the potential to locomote through tightly packed spaces, but turning effectively within unmodelled and unsensed environments remains challenging. Inspired by a behavior observed in the tiny nematode worm C. elegans, we propose a novel in-place turning gait for elongated limbless robots. To simplify the control of the robots' many internal degrees-of-freedom, we introduce a biolog...Show More
State-of-the-art coverage planning methods perform well in simple environments but take an ineffectively long time to converge to an optimal solution in complex three-dimensional (3D) environments. As more structures are present in the same volume of workspace, these methods slow down as they spend more time searching for all of the nooks and crannies concealed in three-dimensional spaces. This wo...Show More
The complexity associated with the control of highly-articulated legged robots scales quickly as the number of joints increases. Traditional approaches to the control of these robots are often impractical for many real-time applications. This work thus presents a novel sampling-based planning approach for highly-articulated robots that utilizes a probabilistic graphical model (PGM) to infer in rea...Show More
Locomoting microscale robots-microswimmers-have the potential to impact numerous applications due to their ability to selectively interact with their environment with microscale control. Previous microswimmer designs lack either submicron-level precision over their construction or instantaneous control over their shape. Thus, existing microswimmer designs limit the control afforded over microswimm...Show More
Snake robots have the potential to maneuver through tightly packed and complex environments. One challenge in enabling them to do so is the complexity in determining how to coordinate their many degrees-of-freedom to create purposeful motion. This is especially true in the types of terrains considered in this work: environments full of unmodeled features that even the best of maps would not captur...Show More
This work proposes a method of footstep placement that controls system energy to enable a dynamically-safe walking behavior. Contrasting many other works that treat rough terrain as a series of disturbances that need to be mitigated with control, we provide some insight into how energy-targeted foot placement is enough to allow a passive system to transit over rough terrain. This work explores the...Show More
This work presents a novel architecture that unifies footstep planning, motion planning, and online feedback control for legged robots moving through complex environments. Our approach contrasts related prior works that treat planning and control as separate components in a hierarchical framework (first plan, then control). Though prior works have demonstrated success, existing state-of-the-art pl...Show More
Sampling-based motion planning algorithms provide a means to adapt the behaviors of autonomous robots to changing or unknown a priori environmental conditions. However, as the size of the space over which a sampling-based approach needs to search is increased (perhaps due to considering robots with many degree of freedom) the computational limits necessary for real-time operation are quickly excee...Show More
The Carnegie Mellon University Biorobotics Laboratory was invited to bring snake robots to Mexico City to assist with search and rescue efforts in the wake of the September 2017 earthquake. We travelled with the Mexican Red Cross to collapsed building sites, and deployed a snake robot within one building to obtain a camera view in two voids that conventional search cameras could not access. We con...Show More
Decentralized control architectures, such as those conventionally defined by central pattern generators, independently coordinate spatially distributed portions of articulated bodies to achieve system-level objectives. State of the art distributed algorithms for reinforcement learning employ a different but conceptually related idea; independent agents simultaneously coordinating their own behavio...Show More