Mathias Broxvall

ICRA Conference 2010 Conference Paper

An evaluation of local autonomy applied to teleoperated vehicles in underground mines

• Johan Larsson 0001
• Mathias Broxvall
• Alessandro Saffiotti

Autonomous vehicles are being increasingly introduced in the mining industry. While these may offer high safety and high productivity, fully autonomous solutions are not always applicable or economically viable. Teleoperation is an attractive option, since it increases safety and comfort of the drivers. Unfortunately, the difficulty to operate the vehicle remotely often results in reduced productivity. In this paper, we show that techniques from the field of mobile robotics can be used to mitigate this problem. We extend a commercial teleoperation system for use in underground mines with a local autonomy functionality, with the main purpose to evaluate if the achieved productivity improvement motivates development of general algorithms and a fully commercial implementation. We then describe a user study performed in an underground mine with a 38 tonne articulated wheel loader, which proves that local autonomy gives a significant improvement in productivity of the teleoperation system, while retaining or even reducing the maintenance costs.

IROS Conference 2008 Conference Paper

Digital representation of everyday objects in a robot ecology via proxies

• Md. Jayedur Rashid
• Mathias Broxvall
• Alessandro Saffiotti

Robotic middlewares increasingly allow the seamless integration of multiple heterogeneous robots into one distributed system. Unfortunately, very simple devices like tagged everyday objects and smart objects are left orphan in this otherwise pervasive trend. We claim that the inclusion of simple everyday objects as part of distributed robot systems would have many advantages, and propose a design pattern to allow this inclusion. We make this pattern concrete by describing an implementation of it using a specific multi-robot middleware, called PEIS-Ecology Middleware. We also show an illustrative experiment which integrates everyday objects in a smart home equipped with mobile robots as well as more advanced distributed sensor nodes.

IROS Conference 2008 Conference Paper

Laser based intersection detection for reactive navigation in an underground mine

• Johan Larsson 0001
• Mathias Broxvall
• Alessandro Saffiotti

In this paper we propose a new feature detection algorithm to enable junction recognition intended for high speed reactive navigation in tunnel like environments. We also present an extensive experimental evaluation of the algorithm based on data recorded in a real mine. The algorithm is faster and has less environmental constraints than similar algorithms that can be found in the literature.

IROS Conference 2008 Conference Paper

The PEIS-Ecology project: Vision and results

• Alessandro Saffiotti
• Mathias Broxvall
• Marco Gritti
• Kevin LeBlanc
• Robert Lundh
• Md. Jayedur Rashid
• BeomSu Seo
• Young-Jo Cho

The vision of an Ecology of Physically Embedded Intelligent Systems, or PEIS-Ecology, combines insights from the fields of autonomous robotics and ambient intelligence to provide a new approach to building robotic systems in the service of people. In this paper, we present this vision, and we report the results of a four-year collaborative research project between Sweden and Korea aimed at the concrete realization of this vision. We focus in particular on three results: a robotic middleware able to cope with highly heterogeneous systems; a technique for autonomous self-configuration and reconfiguration; and a study of the problem of sharing information of both physical and digital nature.

IROS Conference 2007 Conference Paper

Seamless integration of robots and tiny embedded devices in a PEIS-Ecology

• Mirko Bordignon
• Md. Jayedur Rashid
• Mathias Broxvall
• Alessandro Saffiotti

The fields of autonomous robotics and ambient intelligence are converging toward the vision of smart robotic environments, in which tasks are performed via the cooperation of many networked robotic devices. To enable this vision, we need a common communication and cooperation model that can be shared between robotic devices at different scales, ranging from standard mobile robots to tiny embedded devices. Unfortunately, today's robot middlewares are too heavy to run on tiny devices, and middlewares for embedded devices are too simple to support the cooperation models needed by an autonomous smart environment. In this paper, we propose a middleware model which allows the seamless integration of standard robots and simple off-the-shelf embedded devices. Our middleware is suitable for building truly ubiquitous robotics applications, in which devices of very different scales and capabilities can cooperate in a uniform way. We discuss the principles and implementation of our middleware, and show an experiment in which a mobile robot, a commercial mote, and a custom-built mote cooperate in a home service scenario.

ICRA Conference 2006 Conference Paper

An Ecological Approach to Odour Recognition in Intelligent Environments

• Mathias Broxvall
• Silvia Coradeschi
• Amy Loutfi
• Alessandro Saffiotti

We present a new approach for odour detection and recognition based on a so-called PEIS-Ecology: a network of gas sensors and a mobile robot are integrated in an intelligent environment. The environment can provide information regarding the location of potential odour sources, which is then relayed to a mobile robot equipped with an electronic nose. The robot can then perform a more thorough analysis of the odour character. This is a novel approach which alleviates some the challenges in mobile olfaction techniques by single and embedded mobile robots. The environment also provides contextual information which can be used to constrain the learning of odours, which is shown to improve classification performance

ICRA Conference 2006 Conference Paper

PEIS Ecology: Integrating Robots into Smart Environments

• Mathias Broxvall
• Marco Gritti
• Alessandro Saffiotti
• BeomSu Seo
• Young-Jo Cho

We introduce the concept of ecology of physically embedded intelligent systems, or PEIS-ecology. This is a network of heterogeneous robotic devices (PEIS) pervasively embedded in the environment. A PEIS can be as simple as a toaster and as complex as a humanoid robot. PEIS can exchange information at different levels of abstraction, and share both physical and virtual functionalities to perform complex tasks. By putting together insights from the fields of autonomous robotics and of ambient intelligence, the PEIS-ecology approach explores a new road to building assistive, personal, and service robots. In this paper, we discuss this concept, describe a first realization of it, and show an implemented use-case scenario

AAAI Conference 2005 Conference Paper

Recovery Planning for Ambiguous Cases in Perceptual Anchoring

• Mathias Broxvall
• Lars Karlsson

An autonomous robot using symbolic reasoning, sensing and acting in a real environment needs the ability to create and maintain the connection between symbols representing objects in the world and the corresponding perceptual representations given by its sensors. This connection has been named perceptual anchoring. In complex environments, anchoring is not always easy to establish: the situation may often be ambiguous as to which percept actually corresponds to a given symbol. In this paper, we extend perceptual anchoring to deal robustly with ambiguous situations by providing general methods for detecting them and recovering from them. We consider different kinds of ambiguous situations and present planning-based methods to recover from them. We illustrate our approach by showing experiments involving a mobile robot equipped with a color camera and an electronic nose.

IROS Conference 2004 Conference Paper

Putting olfaction into action: using an electronic nose on a multi-sensing mobile robot

• Amy Loutfi
• Silvia Coradeschi
• Lars Karlsson
• Mathias Broxvall

Olfaction is a challenging new sensing modality for intelligent systems. With the emergence of electronic noses it is now possible to detect and recognise a range of different odours for a variety of applications. An existing application is to use electronic olfaction on mobile robots for the purpose of odour based navigation. In this work, we introduce a new application where electronic olfaction is used in cooperation with other types of sensors on a mobile robot in order to acquire the odour property of objects. The mobility of the robot facilitates the execution of specific perceptual actions, such as moving closer to objects to acquire odour properties. Additional sensing modalities provides the spatial detection of objects and electronic olfaction then acquires the odour property which can be used for discrimination and recognition of the object being considered. We examine the problem of deciding when, how and where the e-nose should be activated by planning for active perception. We investigate the use of symbolic reasoning techniques in this context and consider the problem of integrating the information provided by the e-nose with both prior information and information from other sensors (e. g. , vision). Finally, experiments are performed on a mobile robot equipped with an e-nose together with a variety of sensors that can perform decision making tasks in realistic environments.

AIJ Journal 2003 Journal Article

Point algebras for temporal reasoning: Algorithms and complexity

• Mathias Broxvall
• Peter Jonsson

We investigate the computational complexity of temporal reasoning in different time models such as totally-ordered, partially-ordered and branching time. Our main result concerns the satisfiability problem for point algebras and point algebras extended with disjunctions—for these problems, we identify all tractable subclasses. We also provide a number of additional results; for instance, we present a new time model suitable for reasoning about systems with a bounded number of unsynchronized clocks, we investigate connections with spatial reasoning and we present improved algorithms for deciding satisfiability of the tractable point algebras.

AAAI Conference 2002 Conference Paper

A Method for Metric Temporal Reasoning

• Mathias Broxvall

Several methods for temporal reasoning with metric time have been suggested—for instance, Horn Disjunctive Linear Relations (Horn DLRs). However, it has been noted that implementing this algorithm is non-trivial since it builds on fairly complicated polynomial-time algorithms for linear programming. Instead, an alternative approach which augments Allen’s interval algebra with a Simple Temporal Problem (STP) has been suggested (Condotta, 2000). In this paper, we present a new point-based approach STP∗ for reasoning about metric temporal constraints. STP∗ subsumes the tractable preconvex fragment of the augmented interval algebra and can be viewed as a slightly restricted version of Horn DLRs. We give an easily implementable algorithm for deciding satisfiability of STP∗ and demonstrate experimentally its efficiency. We also give a method for finding solutions to consistent STP∗ problem instances.

KR Conference 2002 Conference Paper

Constraint Satisfaction on Infinite Domains: Composing Domains and Decomposing

• Mathias Broxvall

AIJ Journal 2002 Journal Article

Disjunctions, independence, refinements

• Mathias Broxvall
• Peter Jonsson
• Jochen Renz

An important question in constraint satisfaction is how to restrict the problem to ensure tractability (since the general problem is NP-hard). The use of disjunctions has proven to be a useful method for constructing tractable constraint classes from existing classes; the well-known ‘max-closed’ and ‘ORD-Horn’ constraints are examples of tractable classes that can be constructed this way. Three sufficient conditions (the guaranteed satisfaction property, 1-independence and 2-independence) that each ensure the tractability of constraints combined by disjunctions have been proposed in the literature. We show that these conditions are both necessary and sufficient for tractability in three different natural classes of disjunctive constraints. This suggests that deciding this kind of property is a very important task when dealing with disjunctive constraints. We provide a simple, automatic method for checking the 1-independence property—this method is applicable whenever the consistency of the constraints under consideration can be decided by path-consistency. Our method builds on a connection between independence and refinements (which is a way of reducing one constraint satisfaction problem to another.)