Author name cluster

Erwin Prassler

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

18 papers

1 author row

ICRA Conference 2023 Conference Paper

LiDAR-based Indoor Localization with Optimal Particle Filters using Surface Normal Constraints

Heruka Andradi
Sebastian Blumenthal
Erwin Prassler
Paul G. Plöger

Accurate and robust localization systems are often highly desired in autonomous mobile robots. Existing LiDAR-based localization systems generally use standard particle filters which suffer from the well-known particle degeneracy problem. Furthermore, standard particle filters are ill-suited for handling discrepancies between maps and the actual operating environments. In this work, we present an effective LiDAR-based indoor localization system which addresses these two issues. The particle degeneracy problem is tackled with an efficient implementation of an optimal particle filter. Map discrepancies are then handled with the use of a high-fidelity observation model for accurate particle propagation and a separate low-fidelity observation model for robust weight update. Evaluations were carried out against a standard particle filter baseline on both real-world and simulated data from challenging indoor environments. The proposed system was found to show significantly better performance in-terms of accuracy, robustness to ambiguity, and robustness to map discrepancies. These performance gains were observed even with more than ten times smaller particle set sizes than in the baseline, while the increase in the computation time per particle was only around 20%.

ICRA Conference 2019 Conference Paper

Semantic mapping extension for OpenStreetMap applied to indoor robot navigation

Lakshadeep Naik
Sebastian Blumenthal
Nico Huebel
Herman Bruyninckx
Erwin Prassler

In this work a graph-based, semantic mapping approach for indoor robotics applications is presented, which is extending OpenStreetMap (OSM) with robotic-specific, semantic, topological, and geometrical information. Models are introduced for basic indoor structures such as walls, doors, corridors, elevators, etc. The architectural principles support composition with additional domain and application-specific knowledge. As an example, a model for an area is introduced, and it is explained how this can be used in navigation. A key advantage of the proposed graph-based map representation is that it allows exploiting the hierarchical structure of the graphs. Finally, the compatibility of the approach with existing, grid-based motion planning algorithms is shown.

IROS Conference 2018 Conference Paper

A Workbench for Quantitative Comparison of Databases in Multi-Robot Applications

Rubanraj Ravichandran
Erwin Prassler
Nico Huebel
Sebastian Blumenthal

Robots generate large amounts of data which need to be stored in a meaningful way such that they can be used and interpreted later. Such data can be written into log files, but these files lack the querying features and scaling capabilities of modern databases - especially when dealing with multi-robot systems, where the trade-off between availability and consistency has to be resolved. However, there is a plethora of existing databases, each with its own set of features, but none designed with robotic use cases in mind. This work presents three main contributions: (a) structures for benchmarking scenarios with a focus on networked multi-robot architectures, (b) an extensible workbench for benchmarking databases for different scenarios that makes use of Docker containers and (c) a comparison of existing databases given a set of multi-robot use cases to showcase the usage of the framework. The comparison gives indications for choosing an appropriate database.

IROS Conference 2015 Conference Paper

An approach for a distributed world model with QoS-based perception algorithm adaptation

Sebastian Blumenthal
Nico Hochgeschwender
Erwin Prassler
Holger Voos
Herman Bruyninckx

This paper presents a distributed world model that is able to adapt to changes in the Quality of Service (QoS) of the communication layer by online reconfiguration of perception algorithms. The approach consists of (a) a mechanism for storage, exchange and processing of world model data and (b) a feedback loop that incorporates reasoning techniques to adapt to QoS changes immediately. The latter introduces a Level of Detail (LoD) metric based on a spatial resolution in order to infer an upper bound for the amount of data that can be transmitted without violating an application specific transmission delay. Experiments have been performed with Octree-based subsampling techniques applied to data originating from a RGB-D camera using simulated and real-world data sets for timevarying bandwidth values as employed QoS measure.

ICRA Conference 2013 Conference Paper

A scene graph based shared 3D world model for robotic applications

Sebastian Blumenthal
Herman Bruyninckx
Walter Nowak
Erwin Prassler

This paper presents a novel approach for representing and maintaining a shared 3D world model for robotic applications. This approach is based on the scene graph concept which has been adapted to the requirements of the robotic domain. A key feature is the temporal and centralized sharing of all available 3D data in the leaves of the graph structure. The approach enables tracking of dynamic objects, incorporates uncertainty and allows for annotations by semantic tags. A demonstration is given for a perception application that exploits the temporal sharing of 3D data. A Region of Interest (ROI) is extracted from the stored scene data in order to accelerate processing cycle times.

ICRA Conference 2011 Conference Paper

KUKA youBot - a mobile manipulator for research and education

Rainer Bischoff 0002
Ulrich Huggenberger
Erwin Prassler

Establishing mobile manipulation as a powerful key technology for the cognitive factory requires mobile manipulation platforms, which at the same time pay attention to industrial requirements, meet requirements of education and research and last, but not least, come with a decent price tag. KUKA has recently launched a major research and development effort towards designing a mobile manipulation platform that meets these requirements and can serve as a reference platform for industry, research and education at the same time. Although the initiative has just left the starting blocks, a first off-spring, the KUKA youBot, an omni-directional mobile manipulator has just seen the light of day. In this paper we report on the development of the first prototypes.

ICRA Conference 2011 Conference Paper

Towards identification of best practice algorithms in 3D perception and modeling

Sebastian Blumenthal
Erwin Prassler
Jan Fischer
Walter Nowak

Robots need a representation of their environment to reason about and to interact with it. Different 3D perception and modeling approaches exist to create such a representation, but they are not yet easily comparable. This work tries to identify best practice algorithms in the domain of 3D perception and modeling with a focus on environment reconstruction for robotic applications. The goal is to have a collection of refactored algorithms that are easily measurable and comparable. The realization follows a methodology consisting of five steps. After a survey of relevant algorithms and libraries, common representations for the core data-types Cartesian point, Cartesian point cloud and triangle mesh are identified for use in harmonized interfaces. Atomic algorithms are encapsulated into four software components: the Octree component, the Iterative Closest Point component, the k-Nearest Neighbors search component and the Delaunay triangulation component. A sample experiment demonstrates how the component structure can be used to deduce best practice.

IROS Conference 2010 Conference Paper

Component-based refactoring of motion planning libraries

Davide Brugali
Walter Nowak
Luca Gherardi
Alexey Zakharov
Erwin Prassler

Most of the current state of the art motion planning software libraries are not easily interchangeable, because core concepts are represented with different data structures, application programming interfaces (API) are not compatible, or algorithms are encapsulated in modules organized in mutually exclusive abstraction hierarchies. These problems limit the possibility to reuse different libraries in the same application interchangeably and to compare their quality attributes (performance, completeness, etc.). An approach to overcome these shortcomings is refactoring, a technique that aims to restructure a set of existing software libraries without affecting their external behavior in order to harmonize their architecture, data structures, and APIs. This paper presents a component-based refactoring approach that has allowed the transition from motion planning libraries, taking the object-oriented framework CoPP as basis, to a component-based system. In particular we describe a four-step application of well-known architecture refactoring patterns that redistributes the responsibilities among the classes, harmonizes the common data structures and reduces the coupling degree. The obtained system represents a composition of reusable components that are easy to customize and offer different algorithms to resolve the same problem. In this way the user could quickly compile a new motion planning application by simply choosing which algorithm to use for each functionality.

ICRA Conference 2009 Conference Paper

Automatic stimulation of experiments and learning based on prediction failure recognition

Alex Juarez
Björn Kahl
Timo Henne
Erwin Prassler

In this paper we focus on the task of automatically and autonomously initiating experimentation and learning based on the recognition of prediction failure. We present a mechanism that utilizes conceptual knowledge to predict the outcome of robot actions, observes their execution and indicates when discrepancies occur. We show how this mechanism was applied to a robot that learns using the paradigm of learning by experimentation, and present first results obtained from this implementation.

IROS Conference 2007 Conference Paper

Comparative evaluation of robotic software integration systems: A case study

Azamat Shakhimardanov
Erwin Prassler

One might expect that after nearly 50 years of research in robot manipulation and mobile robotics the architectural design of robot systems has converged to a small set of best practice solutions, very much like in the area of operating systems, where the world is dominated by less then a handful systems. Quite the opposite is the case. It is only a small overstatement to say that almost every lab has brewed its own solution for robot control architecture, middleware and software integration concepts. One reason for this situation is the fact that the complexity and variety of systems and applications has grown considerably since then leading to a diversity of approaches. Another reason is clearly the lack of any sound methodology to measures and compare architectural designs. This article tries to address the problem by proposing a comparison and evaluation methodology for robotics software systems. The methodology facilitates an assessment of software systems through experimentation and takes into account the possible operational profile and quality attribute requirements of the robotic application. The approach is validated through the evaluation of three software systems, i. e. GenoM, ORCA2 and GO. The results suggest possible applicability domains of each system and show the efficiency of the approach.

ICRA Conference 2004 Conference Paper

Reflective Navigation: Individual Behaviors and Group Behaviors

Boris Kluge
Erwin Prassler

An approach to motion planning among moving obstacles is presented, whereby obstacles are modeled as intelligent decision-making agents. The decision-making processes of the obstacles are assumed to be similar to that of the mobile robot. A probabilistic extension to the velocity obstacle approach is used as a means for navigation and modeling uncertainty about the moving obstacles' decisions.

IROS Conference 2002 Conference Paper

Motion coordination between a human and a mobile robot

Erwin Prassler
Dirk Bank
Boris Kluge

In this paper we describe an approach to coordinating the motion of a human with a mobile robot moving in a populated, continuously changing, natural environment. The approach is based on a method for motion planning amongst moving obstacles known as the velocity obstacle approach. We extend this method by a method for tracking a virtual target which allows us to vary the robot's heading and velocity with the locomotion of the accompanied person and the state of the surrounding environment. Our test application is a wheelchair accompanying a person through the concourse of a railway station.

IROS Conference 2002 Conference Paper

Statistical recognition of motion patterns

Jörg Illmann
Boris Kluge
Erwin Prassler

This paper addresses the problem of people detection in dynamic environments in real-time and the extraction of typical motion patterns. The need for estimation of peoples movements with a mobile robot is essential for many applications in the field of service robotics. One key prerequisite for a machine to interact intelligently with people is its ability to recognize humans and their behavior. This paper presents an approach for tracking people in dynamic environments and to determine their behavior.

ICRA Conference 2001 Conference Paper

Fast and Robust Tracking of Multiple Moving Objects with a Laser Range Finder

Boris Kluge
Christian Köhler 0004
Erwin Prassler

In this paper we focus on the task of tracking multiple moving objects in rapidly changing, dynamic environments. Objects are extracted from laser range finder images and correspondences between successive images are established by network optimization techniques. The approach is implemented on a robotic wheelchair, used in two applications and evaluated experimentally.

ICRA Conference 2000 Conference Paper

A Robotic Road Sweeper

Erwin Prassler
Dirk Schwammkrug
Bertram Rohrmoser
G. Schmidl

The hardware and software design of a robotic road sweeper is presented. The basic vehicle used is the commercial road sweeper KMR 1200 manufactured by Alfred Karcher GmbH, Germany. This vehicle has been re-designed and augmented by mechanical and electronic components to allow automatic control of both the drive system and the cleaning system. The road sweeper has been further equipped with a navigation system to support autonomous locomotion and operation of the vehicle. The system is intended to clean areas such as the parking space of supermarkets or airports, or factory premises and backyard. The system will be used to handle situations and events which typically occur in public environments which include unknown stationary obstacles such as palettes or containers with goods, parked vehicles or shopping carts left in the workspace, also moving objects such as moving cars or people or animals walking or running across the parking space.

ICRA Conference 1997 Conference Paper

Office waste cleanup: an application for service robots

Erwin Prassler
Eleni Stroulia
Matthias Strobel

Waste cleanup is a task which occurs in a great variety of domains and contexts. In spite of the variety of the causes and the types of waste, cleaning it up typically involves dirty, dull, strenuous and sometimes hazardous actions. Thus waste cleanup constitutes a natural task for service robots. In this paper, we describe an office robot, DAVID, who in addition to collecting and delivering mail and stationary, cleans up offices from garbage. We describe, the system's flexible functional architecture and its various components. We identify some functionalities critical in waste-cleanup tasks and describe how they are accomplished in DAVID. The paper closes with the discussion of an experiment which demonstrates the performance of the system, and with a set of conclusions we drew from this work.

ICRA Conference 1995 Conference Paper

Position Estimaton Using Equidistance Lines

Erwin Prassler
Evangelos E. Milios

An approach to perception-based position estimation is presented. The approach employs a representation of positional information which is based on a global, curvilinear coordinate system which is grounded in the real world. This coordinate system is spanned by the contours of visible objects and by so-called equidistance lines which are constructed from the object contours. Equidistance lines can be computed from arbitrarily curved contours and do not require an analytical representation of these contours. The main advantage of a spatial representation based on equidistance lines is that it does not depend on the existence of salient spatial features in the environment. Furthermore, the global curvilinear coordinate system allows a straightforward transition between the local frames of reference associated with local perceptions. To estimate the position of a robot vehicle over a sequence of local sensor images requires only a minimal number of object contours to be visible or partially visible in these images and a qualitative correspondence of these object contours to be maintained.

IROS Conference 1994 Conference Paper

Motion planning amongst arbitrarily moving unknown objects

Erwin Prassler
Evangelos E. Milios

An approach to motion planning amongst arbitrarily moving unknown objects is presented. As opposed to other approaches to motion planning we avoid the assumption that the motion parameters and the shape of moving objects are known a priori or can be predicted over longer time intervals. By giving up this assumption, traditional methods such as space-time representation and search in space-time no longer apply. Our approach is based on a massively parallel network of simple processing elements. A relaxation process, which is driven by the simultaneous execution of a simple formula in these processing elements, creates a two-dimensional distribution of real numbers, denoted as potentials, which encodes information about collision-free trajectories. Our approach is different from classical algorithmic motion planning in that we do not employ an analytical planning or search algorithm. Instead, desired behaviors, such as the avoidance of moving objects, are achieved through adroit manipulation of the two-dimensional potential distribution. >