48 results for MacDonald, Bruce, Conference item

  • A task representation based on elementary targets (ETs) and execution control rules (ECRs)

    Abbas, Tanveer; MacDonald, Bruce (2009)

    Conference item
    The University of Auckland Library

    Internal task representation is a key design choice for programming by demonstration (PbD) systems. A good representation must include all the desired effects of the task and a set of rules to guide the execution process. Most existing task representations describe the task as a set of primitive actions which can be executed one by one using the specified pre and post conditions to achieve the task goals. We consider two main issues: i) a primitive action may not result in the same effect each time it is executed depending upon the initial conditions of the robot and changes in the environment; and ii) runtime changes in the environment may change the execution priority of the primitives and require termination of a primitive prior to its completion. We propose two improvements to address the above two issues. In the proposed task representation the primitives are replaced by elementary targets - the desired effects, and the pre/post conditions are replaced with execution control rules (ECRs). The proposed ECRs demonstrate better control of the task execution flow by invoking five actions - initiation, termination, completion, suspension and resumption. Example tasks are presented in a helicopter simulator to evaluate the proposed task representation.

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  • Designing a Mixed Reality Framework for Enriching Interactions in Robot Simulations

    Chen, IY; MacDonald, Bruce; Wuensche, Burkhard (2010)

    Conference item
    The University of Auckland Library

    Experimentation of expensive robot systems typically requires complex simulation models and expensive hardware setups for constructing close-to-real world environments in order to obtain reliable results and draw insights to the actual operation. However, the test-development cycle is often time-consuming and resource demanding. A cost-effective solution is to conduct experiments by replacing expensive or dangerous components with simulated counterparts. Based on the concept of Mixed Reality (MR), robot simulation systems can be created to involve real and virtual entities in the simulation loop. However, seamless interaction between objects from the real and the virtual world remains a challenge. This paper presents a generic framework for constructing MR environments that facilitate interactions between objects from different dimensions of reality. In comparison to previous frameworks, we propose a new interaction scheme that describes the necessary stages for creating interactions between real and virtual objects. We demonstrate the strength of our MR framework and the proposed MR interaction scheme in the context of robot simulation. 1

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  • Designing a robotic assistant for healthcare applications

    Kuo, I-Han; Broadbent, Elizabeth; MacDonald, Bruce (2008)

    Conference item
    The University of Auckland Library

    The population of the world is ageing rapidly. By 2050, the population aged 85 and over will be three times more than it is now. This phenomenon has caused several issues in the current health service system, especially workforce shortages in the health sector and a lack of space in aged care facilities (ACFs). In the face of these issues, home-based and community-based healthcare services have been identified as necessary in many developed countries to promote ageing-inplace and independent living in order to: 1. Lower the demands on health services and hence improve the quality of the services delivered, and 2. Maintain the quality of life of the older population by enabling them to be close to their families. For the last decade, a rising interest in personal robots as part of the technical solution in decentralised health services has led to an extensive range of research and implementations of health service and personal assistant robots. This paper describes a new research project to develop an assistant robot capable of interacting with patients, taking vital signs measurements and recording the data in healthcare environments such as aged care facilities, hospitals or personal homes. Current progress includes a comprehensive literature survey on recent health service robots with a list of issues in the area and an initial human-robot interaction study. The robot is currently interfaced with a blood pressure monitor and has a 3D face which is capable of displaying a range of different emotions with lips synchronized to speech.

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  • Dynamic Reconfiguration for Robot Software

    Zheng, Yufei; Warren, Ian; MacDonald, Bruce (2006)

    Conference item
    The University of Auckland Library

    Robot applications are autonomous systems that operate in highly dynamic surroundings. Consequently, they are susceptible to changing environmental characteristics and unanticipated resource breakdowns. Furthermore, they are often required to operate for extended periods. Dynamic reconfiguration provides a powerful mechanism to enhance robot adaptability, and to allow the software to be maintained at run-time. It allows "on-the-fly" reconfiguration of robot software components to change algorithms and hardware drivers. In this paper we present an approach towards dynamic reconfiguration for robot software. The paper addresses requirements and design details for carrying out changes safely and efficiently at run-time. Further, dynamic reconfiguration is applied to two robot navigation systems with different design properties in a case study. Results show efficiency has a heavy dependence upon the choice of interaction technique between processing entities (objects). Applications built from objects that communicate asynchronously can be reconfigured more efficiently than alternative applications where inter-object communication is via explicit method invocation

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  • Evaluation of dimensional analysis in robotics

    Biggs, GM; MacDonald, Bruce (2006)

    Conference item
    The University of Auckland Library

    Robot programs typically manage a substantial amount of dimensioned data. However, existing robot programming tools do not directly support the description and manipulation of dimensioned quantities. A new data type has been proposed for managing dimensioned data in robot software. The design removes much of the hard work of using and ensuring correctness in dimensional data and allows mixing of units using dimensional analysis. An initial implementation has been created by extending the Python interpreter. This paper evaluates the proposal for dimensioned data in robotic systems, using established qualitative evaluation criteria for programming languages, based on the design and implementation, human factors, software engineering, and the application domain. In addition the paper shows that the method can be formalised, and that it is able to support coordinate systems. A set of unit tests is reported for the implementation. Together these evaluations show the proposed dimensioned data system to be implementable, self-consistent, and useful in robotics. The proposed design improves robot programming where dimensioned data is involved.

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  • Generic interfaces for robotic limbs

    Biggs, Geoffrey; MacDonald, Bruce (2006)

    Conference item
    The University of Auckland Library

    Generic interfaces to robot hardware can improve the programming process by making it easier for developers to port applications between di???erent robotic systems. The Player project provides abstract interfaces to aide porting, but until recently did not have any direct support for robotic limbs. This paper describes the design and implementation of three new generic interfaces for robotic limbs and grippers: a low-level interface for controlling limb joints, a high-level interface for controlling end-e???ector pose, and an interface for controlling grippers. The design of the interfaces allows robot applications to quickly be ported between di???erent robotic limbs and di???erent robots. The interfaces are implemented in the Player project, with support provided in the driver for Pioneer robots, allowing the interfaces to be used to control the Pioneer robot arm and gripper. Other drivers are expected to be developed in the future, providing support for other robotic limbs.

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  • Improving The 2.5D STAGE Robotic simulator

    Wong, N; Peng Hsu, JC; Collett, Toby; MacDonald, Bruce (2008)

    Conference item
    The University of Auckland Library

    The open source Stage simulator is a plug-in for the Player robotic software system, that enables the user to test robotic devices in a simulated environment. While designing and building the hardware for a new robotic system might consume numerous months, the Stage simulator provides for building a simulation world with different robotic devices, and for the execution of different tasks, in a time frame of less than a week. Recent additions to Stage include a 2.5D version for simulating objects with simple height properties. However, the 2.5D version of Stage is incomplete. This project aims to provide a complete working solution for 2.5D. Several changes to Stage 2.5D are reported, including improvements to the collision detection and the addition of a gripper device that moves in the z direction. The solution for the collision detection issue provides full 2.5D collision detection functionality and the gripper model is used to allow the robot to complete simple 2.5D tasks such as stacking an object on top of another.

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  • Integration of a 3D-TOF camera into an autonomous, mobile robot system

    Hussmann, S; Schauer, D; MacDonald, Bruce (2009)

    Conference item
    The University of Auckland Library

    3D imaging systems can provide valuable information for autonomous robot navigation. Still the most significant challenge in robot navigation is to have knowledge of 3D dynamic information about the object of interest in the environment. Time-of-Flight (TOF) sensors have recently become available at reasonable prices and offer the possibility to deliver the dynamic object information required for robot navigation. In comparison to stereo vision systems and laser range scanners they combine the advantages of active sensors providing accurate distance measurements and camera-based systems recording a 2D matrix at a high frame rate. This paper focuses on the integration of a TOF sensor into an autonomous, mobile robot system. Experimental results show that the TOF sensor is more suited for robot navigation than the existing laser range system.

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  • Markerless Augmented Reality for Robots in Unprepared Environments

    Chen, Ian; MacDonald, Bruce; Wuensche, Burkhard (2008)

    Conference item
    The University of Auckland Library

    Augmented Reality (AR) can assist humans in understanding complex robot information, and improve Human and Robot Interaction (HRI). However, many restrictions are imposed by the underlying technology used and thus have lim- ited current AR systems to operate in con- trolled or modi ed robot environments. This hinders the wide spread use of AR for di er- ent robot applications. This paper presents a markerless AR system that combines recent tracking and detection techniques for AR vi- sualisation of robot task relevant information. We employ natural feature tracking techniques to compute the camera pose for accurate reg- istration of virtual objects. Automatic relocal- isation of the camera pose is achieved using a planar object detection algorithm which recov- ers from tracking failures. Experiments using a camera mounted on a mobile ground robot demonstrated accurate tracking and successful recovery of planar features in an unprepared indoor environment.

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  • Measuring and improving the accuracy of ARDev using a square grid

    Fung, Kathy; MacDonald, Bruce; Collett, Toby (2006)

    Conference item
    The University of Auckland Library

    Augmented reality (AR) systems superimpose 3D virtual objects on top of a real scene. Most applications require the AR system to maintain an accurate registration between the virtual objects and the real scene. Many AR systems use parameters obtained from the camera calibration to set up a virtual camera that models the real camera. Thus, inaccuracy in camera calibration can adversely affect the registration of an AR system. This paper proposes a calibration improvement algorithm which measures and improves accuracy of a robotics AR system that is currently used in our lab. The algorithm uses a square grid pattern as a calibration device. The vertices of the grid are defined as calibration points. The image coordinates of the calibration points are extracted using image processing technique. By comparing the difference between these image coordinates and those that are calculated using the camera parameters, the accuracy of the system can be measured. The registration error found can be used to adjust the camera parameters accordingly and thereby improves the accuracy of the system. Experiments have shown that the calibration improvement algorithm is feasible and it can be used to measure and minimise the registration error of the AR system.

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  • Real Time Simultaneous Localisation and Mapping for the Player Project

    Yang, Yung-Hsun; MacDonald, Bruce; Stol, Karl (2008)

    Conference item
    The University of Auckland Library

    This paper presents the development of a real time Simultaneous Localisation and Mapping (SLAM) application for generic robot plat- forms using Player, called the Real Time SLAM Proxy (RSP). The Extended Kalman Filter (EKF) and Multiple Particle Filter (MPF) SLAM algorithms are implemented in RSP, and experimental results are provided. RSP is in- tended for nonholonomic robots that operate in 2-D outdoor environments where landmarks can be modelled by cylindrical features and de- tected using laser range nders.

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  • Realtime Debugging for Robotics Software

    Gumbley, Luke; MacDonald, Bruce (2009)

    Conference item
    The University of Auckland Library

    Conventional software debugging constructs are insu cient for debugging robotic software due primarily to the assumption of a deter- ministic, suspendable environment. What is needed is a method to extract and report infor- mation about robotic software execution while continuing execution in the real world environ- ment. A previously theorized debugging con- struct called a tracepoint has been implemented within both a C and a Python debugger. The NetBeans IDE was modi ed to provide an ex- tensible user interface. A plugin-based visu- alisation system for rendering trace data has also been implemented. Presently, plugins for the visualisation system have been created for rendering laser and ultrasonic range nder data from the Player robot library. Benchmark tests show that although there is still signi cant room for improvement, in one typical use case the system adds less than 1% overhead.

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  • Robust trajectory segmentation for programming by demonstration

    Abbas, Tanveer; MacDonald, Bruce (2009)

    Conference item
    The University of Auckland Library

    A novel trajectory segmentation and modeling approach is presented. Trajectory segmentation and matching is an important step in the programming by demonstration (PbD) process to extract the user's intentions from multiple trajectories. To match multiple trajectories, the segmentation and modeling approach must be consistent and robust to disparities caused by robot dynamics and human imperfections. Several curve segmentation approaches have demonstrated substantial potential in the field of image processing and gesture recognition. They emphasize reduction of the degree of mismatch between given and model curves. However they fail to reduce mismatch between models of multiple trajectories recorded to demonstrate the same intention.We propose an M-estimator for trajectory modeling and set up a new segmentation criterion to address the issue. The proposed approach is better suited for PbD of mobile robots. The approach is evaluated for real robot trajectories.

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  • Specifying robot reactivity in procedural languages

    Biggs, Geoffrey; MacDonald, Bruce (2006)

    Conference item
    The University of Auckland Library

    A key part of programming a robotic system is specifying the responses to events that the robot may encounter. Existing methods of programming responses include event loops, reactive languages and hybrid architectures, none of which meet the specific needs of mobile robot programming. This work presents a design for new semantics for specifying reactivity in mobile robot programs, one that allows for effective specification of reactive behaviour within procedural robot programs. An initial evaluation version is implemented in Python. Events and responses are supported as program objects, and are connected together by new statements. Programmers specify connections between events and responses anywhere within the program code, so connections can easily be changed in response to changes in program and robot state

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  • Sketch-Based Robot Programming

    Barber, C; Shucksmith, R; MacDonald, Bruce; Wuensche, Burkhard (2010)

    Conference item
    The University of Auckland Library

    Robots are rapidly becoming a part of everyday life and have now moved from industrial environments to household, medical and entertainment applications. In order to make full use of robots new interfaces need to be developed, which allow inexperienced human users to instruct (program) robots, without having to understand programming and the underlying electronics and mechanics. In this paper we present a novel sketch-based interface for robot programming. We have identified applications which are difficult to represent algorithmically, but can be easily represented with sketch input. We then define a range of sketch impressions allowing the user to define a wide range of behaviours within these application domains. Our system uses a Pioneer robot with an arm and a fixed overhead camera. The user sketches into the camera view and the sketch input is interpreted, mapped into the 3D domain, and translated into robot interactions. Current applications include specification of robot paths and obstacles, covering regions (e.g., patrolling in security applications or seed sowing in agricultural applications), and directing the robot arm, e.g., to pick up objects. A user evaluation of the system demonstrates that the interface is intuitive and, with the exceptions of controlling the arm, all interactions are perceived as easy to perform.

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  • Real-time robust image feature description and matching

    Thomas, Stephen; MacDonald, Bruce; Stol, Karl (2011)

    Conference item
    The University of Auckland Library

    The problem of ???nding corresponding points between images of the same scene is at the heart of many computer vision problems. In this paper we present a real-time approach to ???nding correspondences under changes in scale, rotation, viewpoint and illumination using Simple Circular Accelerated Robust Features (SCARF). Prominent descriptors such as SIFT and SURF ???nd robust correspondences, but at a computation cost that limits the number of points that can be handled on low-memory, low-power devices. Like SURF, SCARF is based on Haar wavelets. However, SCARF employs a novel non-uniform sampling distribution, structure, and matching technique that provides computation times comparable to the state-of-the-art without compromising distinctiveness and robustness. Computing 512 SCARF descriptors takes 12.6ms on a 2.4GHz processor, and each descriptor occupies just 60 bytes. Therefore the descriptor is ideal for real-time applications which are implemented on low-memory, low-power devices.

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  • Augmented Reality Visualisation for Player

    Collett, Toby; MacDonald, Bruce (2006)

    Conference item
    The University of Auckland Library

    One of the greatest challenges when debugging a robot application is understanding what is going wrong. Robots are embodied in a complex, changing and unpredictable real world, using sensors and actuators that are different from humans???. As a result humans may ???nd the development of robotic software to be dif???cult and time consuming. We present an augmented reality visualisation tool for the popular open source Player system, that enhances the developers understanding of the robots world view and thus improves the robot development process.

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  • A comparison between extended kalman filtering and sequential monte carlo technique for simultaneous localisation and map-building.

    Yuen, David; MacDonald, Bruce (2002)

    Conference item
    The University of Auckland Library

    Monte Carlo Localisation has been applied to solve many di erent classes of localisation problems. In this paper, we present a possible Simultaneous Localisation and Map-building implementation using the Sequential Monte Carlo technique. Multiple particle lters are created to estimate both the robot and land- mark positions simultaneously. The proposed technique shows promising results when com- pared with those obtained with the Extended Kalman lter.

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  • An Intuitive Interface for a Cognitive Programming By Demonstration System

    Brageul, David; Vukanovic, Slobodan; MacDonald, Bruce (2008)

    Conference item
    The University of Auckland Library

    A significant challenge in programming robots by demonstration is to accurately capture the user's intentions, so that sensor differences can be managed during playback. Sensor difference can be caused by: natural sensory data variations, minor variations in the task conditions, significant changes in the task scenario, or because the task requires a new set of actions to be executed. This paper presents a design for a programming by demonstration system that focuses on the important goal of capturing the intentions of the user during the demonstration. A gesture interface for a large touch screen is used during demonstration, to capture more clearly the user's intentions for robot movements, and also during a pre- playback session to capture the user's intentions regarding sensor data.

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  • Attitudes of retirement home residents, relatives and staff towards healthcare robots.

    Broadbent, Elizabeth; Tamagawa, Rie; Kerse, Ngaire; Day, Karen; MacDonald, Bruce (2009)

    Conference item
    The University of Auckland Library

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