TechTalks from event: Technical session talks from ICRA 2012

Conference registration code to access these videos can be accessed by visiting this link: PaperPlaza. Step-by-step to access these videos are here: step-by-step process .
Why some of the videos are missing? If you had provided your consent form for your video to be published and still it is missing, please contact support@techtalks.tv

Space Robotics

  • Automatic Rock Recognition from Drilling Performance Data Authors: Zhou, Hang; Hatherly, Peter; Monteiro, Sildomar; Ramos, Fabio; Oppolzer, Florian; Nettleton, Eric; Scheding, Steven
    Automated rock recognition is a key step for building a fully autonomous mine. When characterizing rock types from drill performance data, the main challenge is that there is not an obvious one-to-one correspondence between the two. In this paper, a hybrid rock recognition approach is proposed which combines Gaussian Process (GP) regression with clustering. Drill performance data is also known as Measurement While Drilling (MWD) data and a rock hardness measure - Adjusted Penetration Rate (APR) is extracted using the raw data in discrete drill holes. GP regression is then applied to create a more dense APR distribution, followed by clustering which produces discrete class labels. No initial labeling is needed. Comparisons are made with alternative measures of rock hardness from MWD data as well as state-of-the-art GP classification. Experimental results from an actual mine site show the effectiveness of our proposed approach.
  • Evaluation of the Reconfiguration Effects of Planetary Rovers on their Lateral Traversing of Sandy Slopes Authors: Inotsume, Hiroaki; Sutoh, Masataku; Nagatani, Keiji; Yoshida, Kazuya
    Rovers that are used to explore craters on the Moon or Mars require the mobility to negotiate sandy slopes, on which slippage can easily occur. Such slippage can be reduced by actively readjusting the attitude of the rovers. By changing attitude, rovers can modify the position of their center of gravity and the wheel-soil contact angle. In this study, we discuss the effects of attitude changes on downhill sideslip based on the slope failure mechanism and experiments on reconfiguring the rover attitude and wheel angles. We conducted slope-traversing experiments using a wheeled rover under various roll angles and wheel angles. The experimental results show that the contact angle between wheels and slopes has a dominant influence on sideslip when compared with that of readjusting the rover's center of gravity.
  • Evaluation of Influence of Surface Shape of Locomotion Mechanism on Traveling Performance of Planetary Rovers Authors: Sutoh, Masataku; Nagaoka, Kenji; Nagatani, Keiji; Yoshida, Kazuya
    The surfaces of both the Moon and Mars are covered with loose soil, with numerous steep slopes along their crater rims. Therefore, one of the most important requirements imposed on planetary rovers is their ability to minimize slippage while climbing steep slopes, i.e., the ability to generate a drawbar pull with only a small amount of slippage. To this end, the wheels/tracks of planetary rovers typically have parallel fins called lugs (i.e., grousers) on their surface. Recent studies have reported that these lugs can substantially improve the traveling performances of planetary rovers. Therefore, in this study, we conducted experiments using lightweight two-wheeled and mono-tracked rovers to provide a quantitative confirmation regarding the influence of lugs on the traveling performances of planetary rovers. Based on our experimental results, we confirmed that, although an increase in the number of lugs contributes to the high traveling performance of wheeled rovers, it does not contribute much to that of tracked rovers. Furthermore, an increase in lug height improves the traveling performances of both types of rovers.
  • The Robonaut 2 Hand Designed to Do Work with Tools Authors: Bridgwater, Lyndon; Ihrke, Chris; Diftler, Myron; Abdallah, Muhammad; Radford, Nicolaus; Rogers, Jonathan; yayathi, Sandeep; Askew, Roger, Scott; Linn, Marty
    The second generation Robonaut hand has many advantages over its predecessor. This mechatronic device is more dexterous and has improved force control and sensing giving it the capability to grasp and actuate a wider range of tools. It can achieve higher peak forces at higher speeds than the original. Developed as part of a partnership between General Motors and NASA, the hand is designed to more closely approximate a human hand. Having a more anthropomorphic design allows the hand to attain a larger set of useful grasps for working with human interfaces. Key to the hands improved performance is the use of lower friction drive elements and a redistribution of components from the hand to the forearm, permitting more sensing in the fingers and palm where it is most important. The following describes the design, mechanical/electrical integration, and control features of the hand. Lessons learned during the development and initial operations along with planned refinements to make it more effective are presented.
  • Autonomous Detection of Volcanic Plumes on Outer Planetary Bodies Authors: Lin, Yucong; Bunte, Melissa; Saripalli, Srikanth; Greeley, Ronald
    We experimentally evaluated the efficacy of var- ious autonomous supervised classification techniques for de- tecting transient geophysical phenomena. We demonstrated methods of detecting volcanic plumes on the planetary satellites Io and Enceladus using spacecraft images from the Voyager, Galileo, New Horizons, and Cassini missions. We successfully detected 73-95% of known plumes in images from all four mission datasets. We increased the detection rate by using a training subset. Additionally, we showed that the same tech- niques are applicable to differentiating geologic features, such as plumes and mountains, which exhibit similar appearances in images.
  • Gravity-Independent Mobility and Drilling on Natural Rock Using Microspines Authors: Parness, Aaron; Frost, Matthew; Thatte, Nitish; King, Jonathan
    To grip rocks on the surfaces of asteroids and comets, and to grip the cliff faces and lava tubes of Mars, a 250 mm diameter omni-directional anchor is presented that utilizes a hierarchical array of claws with suspension flexures, called microspines, to create fast, strong attachment. Prototypes have been demonstrated on vesicular basalt and a‘a lava rock supporting forces in all directions away from the rock. Each anchor can support >160 N tangent, >150 N at 45, and >180 N normal to the surface of the rock. A two-actuator selectively-compliant ankle interfaces these anchors to the Lemur IIB robot for climbing trials. A rotary percussive drill was also integrated into the anchor, demonstrating self-contained rock coring regardless of gravitational orientation. As a harder-than-zero-g proof of concept, 20mm diameter boreholes were drilled 83 mm deep in vesicular basalt samples, retaining a 12 mm diameter rock core in 3-6 pieces while in an inverted configuration, literally drilling into the ceiling.

Stochastic in Robotics and Biological Systems

  • Low-Cost Collaborative Localization for Large-Scale Multi-Robot Systems Authors: Prorok, Amanda; Bahr, Alexander; Martinoli, Alcherio
    Large numbers of collaborating robots are advantageous for solving distributed problems. In order to efficiently solve the task at hand, the robots often need accurate localization. In this work, we address the localization problem by developing a solution that has low computational and sensing requirements, and that is easily deployed on large robot teams composed of cheap robots. We build upon a real-time, particle-filter based localization algorithm that is completely decentralized and scalable, and accommodates realistic robot assumptions including noisy sensors, and asynchronous and lossy communication. In order to further reduce this algorithm’s overall complexity, we propose a low-cost particle clustering method, which is particularly well suited to the collaborative localization problem. Our approach is experimentally validated on a team of ten real robots.
  • Robotic Manifold Tracking of Coherent Structures in Flows Authors: Hsieh, M. Ani; Forgoston, Eric; Mather, T, William; Schwartz, Ira
    Tracking Lagrangian coherent structures in dynamical systems is important for many applications such as oceanography and weather prediction. In this paper, we present a collaborative robotic control strategy designed to track stable and unstable manifolds. The technique does not require global information about the fluid dynamics, and is based on local sensing, prediction, and correction. The collaborative control strategy is implemented on a team of three robots to track coherent structures and manifolds on static flows as well as a noisy time-dependent model of a wind-driven double-gyre often seen in the ocean. We present simulation and experimental results and discuss theoretical guarantees of the collaborative tracking strategy.
  • Ensemble Synthesis of Distributed Control and Communication Strategies Authors: Mather, T, William; Hsieh, M. Ani
    We present an ensemble framework for the design of distributed control and communication strategies for the dynamic allocation of a team of robots to a set of tasks. In this work, we assume individual robot controllers are sequentially composed of individual task controllers. This assumption enables the representation of the robot ensemble dynamics as a class of stochastic hybrid systems that can be modeled as continuous-time Markov jump processes where feedback strategies can be derived to control the team's distribution across the tasks. Since the distributed implementation of these feedback strategy requires the estimation of certain population variables, we show how the ensemble model can be expanded to incorporate the dynamics of the information exchange. This then enables us to optimize the individual robot control policies to ensure overall system robustness given some likelihood of resource failures. We consider the assignment of a team of homogeneous robots to a collection of spatially distributed tasks and validate our approach via high-fidelity simulations.
  • Almost-Uniform Sampling of Rotations for Conformational Searches in Robotics and Structural Biology Authors: Yan, Yan; Chirikjian, Gregory
    We propose a new method for sampling the rotation group that involves decomposing it into identical Voronoi cells centered on rotational symmetry operations of the Platonic solids. Within each cell, Cartesian coordinates in exponential coordinates are used to achieve almost-uniform sampling at any level of resolution, without having to store large numbers of coordinates, and without requiring sophisticated data structures. We analyze the shape of these cells, and explain how this can be used in the context of conformational searches in the fields of Robotics and Structural Biology.
  • Randomly Distributed Delayed Communication and Coherent Swarm Patterns Authors: Lindley, Brandon; Mier-Y-Teran-Romero, Luis; Schwartz, Ira
    Previously we showed how delay communication between globally coupled self-propelled agents causes new spatio-temporal patterns to arise when the delay coupling is fixed among all agents [1]. In this paper, we show how discrete, randomly distributed delays affect the dynamical patterns. In particular, we investigate how the standard deviation of the time delay distribution affects the stability of the different patterns as well as the switching probability between coherent states. [1] E. Forgoston and I. Schwartz, “Delay-induced instabilities in selfpropelling swarms,” Phy. Rev. E, vol. 77, 2008.
  • Real-Time Automated Modeling and Control of Self-Assembling Systems Authors: Mermoud, Gregory; Mastrangeli, Massimo; Upadhyay, Utkarsh; Martinoli, Alcherio
    We present the M<sup>3</sup> framework, a formal and generic computational framework for modeling and controlling stochastic distributed systems of purely reactive robots in an automated and real-time fashion. Based on the trajectories of the robots, the framework builds up an internal microscopic representation of the system, which then serves as a blueprint of models at higher abstraction levels. These models are then calibrated using a Maximum Likelihood Estimation (MLE) approach. We illustrate the structure and performance of the framework by performing the online optimization of a simple bang-bang controller for the stochastic self-assembly of water-floating passive modules. The experimental results demonstrate that the generated models can successfully optimize the assembly of desired structures.

Path Planning and Navigation

  • Reliable Indoor Navigation with an Unreliable Robot: Allowing Temporary Uncertainty for Maximum Mobility Authors: Lewis, Jeremy; O'Kane, Jason
    In this work we consider a navigation problem for a very simple robot equipped with only a map, compass, and contact sensor. Our prior work on this problem uses a graph to navigate between the convex vertices of an environment. In this paper, we extend this graph with the addition of a new node type and four new edge types. The new node type allows for more uncertainty in robot position. The presence of one of these new edge types guarantees reliable transitions between these nodes. This enhanced graph enables the algorithm to navigate environment features not solvable by our previous algorithm, including T-junctions and long halls. We also present a heuristic to accelerate the planning process by prioritizing the promising edge tests to perform. Our heuristic effectively focuses the search and qualitative data show that it computes plans with much less computational effort than a naive approach. We describe a simulated implementation of the algorithm that finds paths not previously possible, and a physical implementation that demonstrates the feasibility of executing those plans in practice.
  • Path Planning in Time Dependent Flow Fields Using Level Set Methods Authors: Lolla, Tapovan; Ueckermann, Mattheus Percy; Haley, Patrick; Lermusiaux, Pierre F.J.
    We develop and illustrate an efficient but rigorous methodology that predicts the time-optimal paths of ocean vehicles in continuous dynamic flows. The goal is to best utilize or avoid currents, without limitation on these currents or on the number of vehicles. The methodology employs a new modified level set equation to evolve a front from the starting point of a vehicle until it reaches the desired goal location, combining flow advection with nominal vehicle motion. The optimal path of the vehicle is then obtained by solving a particle tracking equation backward in time. The computational cost of this method increases linearly with the number of vehicles and geometrically with spatial dimensions. The methodology is applicable to any continuous flow and in scenarios with multiple vehicles. Present illustrations consist of the crossing of a canonical uniform jet and its validation using a classic optimization solution, as well as swarm formation in more complex time varying 2D flow fields, including jets, eddies and forbidden regions.
  • Provably Safe Navigation for Mobile Robots with Limited Field-Of-Views in Unknown Dynamic Environments Authors: bouraine, sara; Fraichard, Thierry; salhi, hassen
    This paper addresses the problem of navigating a mobile robot with a limited field-of-view in a unknown dynamic environment. In such a situation, absolute motion safety, i.e. such that no collision will ever take place whatever happens, is impossible to guarantee. It is therefore settled for a weaker level of motion safety dubbed passive motion safety: it guarantees that, if a collision takes place, the robot will be at rest. Passive motion safety is tackled using a variant of the Inevitable Collision State (ICS) concept called Braking ICS, i.e. states such that, whatever the future braking trajectory of the robot, a collision occurs before it is at rest. Passive motion safety is readily obtained by avoiding Braking ICS at all times. Building upon an existing Braking ICS-Checker, i.e. an algorithm that checks if a given state is a Braking ICS or not, this paper presents a reactive collision avoidance scheme called PassAvoid. The main contribution of this paper is the formal proof of PassAvoid's passive motion safety. Experiments in simulation demonstrates how PassAvoid operates.
  • An Efficient Mobile Robot Path Planning Using Hierarchical Roadmap Representation in Indoor Environment Authors: Park, Byungjae; Choi, Jinwoo; Chung, Wan Kyun
    This paper describes a practical approach to solve a path planning problem in a home environment. The proposed approach incrementally constructs the hierarchical roadmap which has a multi-layered structure using a sonar grid map when a mobile robot navigates in unexplored area. The hierarchical roadmap can almost completely cover the traversable areas in the environment. The mobile robot path planner using the hierarchical roadmap can efficiently search for appropriate paths under the limited computing power and time by reducing the search space size. The benefits of the hierarchical roadmap representation were verified by experiments in a home environment.
  • 3D Time-Space Path Planning Algorithm in Dynamic Environment Utilizing Arrival Time Field and Heuristically Randomized Tree Authors: Ardiyanto, Igi; Miura, Jun
    This paper deals with a path planning problem in the dynamic and cluttered environments. The presence of moving obstacles and kinodynamic constraints of the robot increases the complexity of path planning problem. We model the environment and motion of dynamic obstacles in <i>3D time-space</i>. We propose the utilization of <i>the arrival time field</i> for examining the most promising area in those <i>obstacles-occupied</i> 3D time-space for approaching the goal. The arrival time field is used for guiding the expansion of a randomized tree search in a favorable way, considering kinodynamic constraints of the robot. The quality and the optimality of the path are taken into account by performing heuristic methods on the randomized tree. Simulation results are also provided to prove the feasibility, possibility, and effectiveness of our algorithm.
  • High-Speed Navigation of a Uniformly Braking Mobile Robot Using Position-Velocity Configuration Space Authors: Manor, Gil; Rimon, Elon
    This paper considers the problem of fast autonomous mobile robot navigation between obstacles while attempting to maximize velocity subject to safe braking constraints. The paper introduces position-velocity configuration space. Within this space, keeping a uniform braking distance from the obstacles can be modeled as forbidden regions called vc-obstacles. Using Morse Theory, the paper characterizes the critical position-velocity points where two vc-obstacles meet and locally disconnect the free position-velocity space. These points correspond to critical events where the robot's velocity becomes too large to support safe passage between neighboring obstacles. The velocity dependent critical points induce a cellular decomposition of the free position-velocity space into cells. Each cell is associated with a particular range of velocities that can be safely followed by the robot. The paper proposes a practical algorithm that searches the cells' adjacency graph for a maximum velocity path. The algorithm outputs a pseudo time optimal path which maintains safe braking distance from the obstacles throughout the robot motion. Simulations demonstrate the algorithm and highlight the usefulness of taking the path's velocity into account during the path planning process.