In this paper, we present the design and implementation of a multi-robot cooperation framework to collectively execute inter-dependent tasks of an overall complex mission requiring diverse capabilities. Given a hetero...
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ISBN:
(纸本)9728865600
In this paper, we present the design and implementation of a multi-robot cooperation framework to collectively execute inter-dependent tasks of an overall complex mission requiring diverse capabilities. Given a heterogeneous team of robots and task dependencies, the proposed framework provides a distributed mechanism for assigning tasks to robots in an order that efficiently completes the mission. The approach is robust to unreliable communication and robot failures. It is a distributed auction-based approach, and therefore scalable. In order to obtain optimal allocations, effective bid evaluations are needed. Additionally to maintain optimality in noisy environments, dynamic re-allocations of tasks are needed as implemented in dynamic task selection and coalition maintenance scheme that we propose. Real-time contingencies are handled by recovery routines, called Plan B precautions in our framework. Here, in this paper, we present performance results of our framework for robustness in simulations that include variable message loss rates and robot failures. Experiments illustrate robustness of our approach against several contingencies.
This paper proposes a method for dynamically varying the gains of a mobile robot controller that takes into account, not only errors to the reference trajectory but also the uncertainty in the localisation. To do this...
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ISBN:
(纸本)9789897583803
This paper proposes a method for dynamically varying the gains of a mobile robot controller that takes into account, not only errors to the reference trajectory but also the uncertainty in the localisation. To do this, the covariance matrix of a state observer is used to indicate the precision of the perception. CMA-ES, an evolutionary algorithm is used to train a neural network that is capable of adapting the robot's behaviour in real-time. Using a car-like vehicle model in simulation. Promising results show significant trajectory following performances improvements thanks to control gains fluctuations by using this new method. Simulations demonstrate the capability of the system to control the robot in complex environments, in which classical static controllers could not guarantee a stable behaviour.
The classical optimal path following problem considers the problem of moving optimally along a predefined geometric path under technological restrictions. In contrast to optimal path following, optimal tube following ...
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ISBN:
(纸本)9789897581984
The classical optimal path following problem considers the problem of moving optimally along a predefined geometric path under technological restrictions. In contrast to optimal path following, optimal tube following allows deviations from the initial path within a predefined tube to reduce cost even more. The present paper proposes a modern approach that treats this non-convex problem in task space. This novel method also provides a simple way to derive optimal trajectories within a tube described in terms of polygonal lines. Numerical examples are presented that allow to compare the proposed method to existing joint space approaches.
The main contribution of this paper is a method for optimizing the layout of workcells taking into consideration both the reachability of the robot as well as the expected cycle time. To analyse the reachability for s...
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ISBN:
(纸本)9789897583049
The main contribution of this paper is a method for optimizing the layout of workcells taking into consideration both the reachability of the robot as well as the expected cycle time. To analyse the reachability for systems using sensors to pose estimate objects, the method uses a combination of discrete samples over the space in which objects are located and a manipulability measure based on the determinant of the manipulator Jacobian. To compute the expected cycle time for the robot, the method includes a simulated controller, which is optimized to estimate the performance of the physical robot. For the optimization of the workcell layout the proposed method based on applying Gaussian penalties in local minima is compared to three existing methods for global optimization. For the optimization of the simulated controller three different local methods are compared along with one global.
Nowadays available broadband wireless communication technologies offer a broad spectrum of applications and the todays availability of UMTS technology has a great potential in the area of networked robotics. This work...
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ISBN:
(纸本)9789896740009
Nowadays available broadband wireless communication technologies offer a broad spectrum of applications and the todays availability of UMTS technology has a great potential in the area of networked robotics. This work investigates teleoperation of mobile robots via UMTS communication links. First, several scenarios with artificially generated command traffic between mobile robot and operator are analyzed in order to gain knowledge of the link behavior. In a next step real mobile robot hardware is remote controlled via UMTS. Thereby, the robot transmits sensor data and a video stream of its onboard camera while receiving commands from the operator. The focus of this work is set on the measurement and analysis of the round trip time and the packet inter-arrival time of data in different scenarios like the connection of two UMTS nodes, the connection of an Internet PC and an UMTS node, or the behavior of several UMTS nodes generating a large amount of data. The results clearly show how applications for mobile robot teleoperation can efficiently use UMTS communication in order to allow seamless teleoperation between operator and hardware in distant locations.
Autonomous navigation in off-road environments is a challenging task for mobile robots. Recent success in artificial intelligence research demonstrates the suitability and relevance of neural networks and learning app...
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ISBN:
(纸本)9789897583803
Autonomous navigation in off-road environments is a challenging task for mobile robots. Recent success in artificial intelligence research demonstrates the suitability and relevance of neural networks and learning approaches for image classification and off-road robotics. Nonetheless, meaningful decision making processes require semantic knowledge to enable complex scene understanding on a higher abstraction level than pure image data. A promising approach to incooperate semantic knowledge are ontologies. Especially in the off-road domain, scene object correlations heavily influence the navigation outcome and misinterpretations may lead to the loss of the robot, environmental, or even personal damage. In the past, behavior-based control systems have proven to robustly handle such uncertain environments. This paper combines both approaches to achieve a situation-aware navigation in off-road environments. Hereby, the robot's navigation is improved using high-level off-road background knowledge in form of ontologies along with a reactive, and modular behavior network. The feasibility of the approach is demonstrated within different simulation scenarios.
In this work the application of six-axis robots for robot-based industrial X-ray computed tomography (CT) imaging is investigated. In contrast to classical Cartesian manipulators with a turntable used in industrial co...
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ISBN:
(纸本)9789897583803
In this work the application of six-axis robots for robot-based industrial X-ray computed tomography (CT) imaging is investigated. In contrast to classical Cartesian manipulators with a turntable used in industrial cone-beam CT, robots offer increased flexibility regarding scanning trajectories. The increased flexibility with respect to scanning trajectories helps to gather highly informative content from alternative ray paths for a high-quality 3D reconstruction of the object to be scanned. Using numerical simulations we show that this additional informations increase the image quality of a CT scan of a multi-material measuring object, consisting of tantalum spheres and a carbon structure.
This paper relates to the problem of a path following task for a wheeled mobile platform of (2,0) type. Two kinematic control algorithms, Micaelli-Samson algorithm and Soetanto-Lapierre-Pascoal algorithm, which are ba...
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ISBN:
(纸本)9789898565716
This paper relates to the problem of a path following task for a wheeled mobile platform of (2,0) type. Two kinematic control algorithms, Micaelli-Samson algorithm and Soetanto-Lapierre-Pascoal algorithm, which are based on either the Serret-Frenet frame with an orthogonal projection or the Serret-Frenet frame with a nonorthogonal projection of a robot on the desired path, were presented. The additional condition that should be imposed on the function δ, which is a parameter depending on a linear velocity of the robot and on a distance error, was described. The influence of the function δ on the convergence of the non-singular algorithm has been shown using computer simulations.
Domain Specific Languages (DSL) are being used in several fields of industry. This paper shows how a DSL can be used in the wood industry, automizing some tasks through the use of robots. In this paper we also impleme...
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ISBN:
(纸本)9789897583049
Domain Specific Languages (DSL) are being used in several fields of industry. This paper shows how a DSL can be used in the wood industry, automizing some tasks through the use of robots. In this paper we also implement a syntax to define robot instructions inside a high-level abstraction layer to simplify these instructions and to develop a reliable tool for developers in order to avoid errors and allow for faster development. This paper also covers considerations on how to choose the kind of DSL that best fulfills our requirements and provides an example described in detail.
This paper presents the work in progress on the design and testing of a distributed ultrasound-based sensory system for hybrid 1D and 2D environment visualisation. Many common sensors used in robotics, such as infrare...
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ISBN:
(纸本)9789897581984
This paper presents the work in progress on the design and testing of a distributed ultrasound-based sensory system for hybrid 1D and 2D environment visualisation. Many common sensors used in robotics, such as infrared and ultrasonic sensors, cameras and lasers mainly focus on quantifying distances and shapes, while rarely have the ability to differentiate among different sensed surfaces/materials. We propose an inexpensive prototype sensory system based on popular ultrasonic sensors which uses ultrasonic reflections to determine the acoustic reflection coefficients. This additional feature allows differentiating among sensed objects. Moreover, the developed ultrasonic cells are equipped with a microcontroller for basic signal processing and a communication link for integration into a sensor network. In this paper, we discuss the possibility of fusing obtained sensor array data and laser measurements.
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