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Hybrid control strategy for the autonomous transition flight of a fixed-wing aircraft

IEEE Transactions on Control systems Technology 2013年第6期21卷 2194-2211页

作者： Casau, Pedro Cabecinhas, David Silvestre, Carlos Department of Electrical Engineering and Computer Science Institute for Robotics and Systems in Engineering and Science Universidade Técnica de Lisboa Lisbon 1049-001 Portugal Department of Electrical and Computer Engineering Faculty of Science and Technology University of Macau 999078 China

This paper develops a hybrid control strategy that provides autonomous transition between hovered and leveled flights to a model-scale fixed-wing aircraft. The aircraft's closed-loop dynamics are described by means of a hybrid automaton with the hover, transition, level, and recovery operating modes, each one corresponding to a different region of the flight envelope. Linear parameter varying control techniques are employed in hover and level, providing robust local stabilization, and a nonlinear locally input-to-state stable controller provides practical reference tracking to the transition operating mode. These controllers, together with an appropriate choice of reference maneuvers, ensure that a transition from hovered flight to level flight, or vice versa, is achieved. Whenever the aircraft state reaches unexpected values, the recovery controller is triggered in order to drive the aircraft toward stable hovered flight, providing a chance to retry the transition maneuver. The controllers' performance and robustness is assessed within a realistic simulation environment in the presence of sensor noise. © 2013 IEEE.

关键词： Fixed wings

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Aspects of controlling a multifingered gripper

Aspects of controlling a multifingered gripper

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International Conference on Knowledge-Based Intelligent Electronic systems (KES)

作者： T. Doersam T. Fischer Department of Computer Science Institute for Real-Time Computer Systems and Robotics University of Karlsruhe Karlsruhe Germany

Controlling multifingered robot hands makes high demands on the control algorithms and the speed of the control computer. The nonlinear friction, the impact problem and other plant uncertainties require a special kind of control and tuning of the controller. Some simple linear and nonlinear controllers for the Karlsruhe Dexterous Hand are presented and the results and advantages of the controllers are shown. Also, a new adaptive fuzzy controller is presented to overcome the time consuming process of fine-tuning the membership functions. Finally, a short glance at the hardware platform is taken in order to show the control system architecture.

关键词： Grippers Friction Control systems Force control Fuzzy control Force measurement computer science real time systems Robot control Programmable control

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Extending OpenStack Monasca for Predictive Elasticity Control

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Big Data Mining and Analytics 2024年第2期7卷 315-339页

作者： Giacomo Lanciano Filippo Galli Tommaso Cucinotta Davide Bacciu Andrea Passarella Scuola Normale Superiore Pisa 56126Italy the Real-Time Systems Laboratory(RETIS) TelecommunicationsComputer Engineeringand Photonics Institute(TeCIP)Scuola Superiore Sant’AnnaPisa 56127Italy Department of Computer Science University of PisaPisa 56127Italy National Research Council Pisa56127Italy

Traditional auto-scaling approaches are conceived as reactive automations,typically triggered when predefined thresholds are breached by resource consumption *** such rules at scale is cumbersome,especially when resources require non-negligible time to be *** paper introduces an architecture for predictive cloud operations,which enables orchestrators to apply time-series forecasting techniques to estimate the evolution of relevant metrics and take decisions based on the predicted state of the *** this way,they can anticipate load peaks and trigger appropriate scaling actions in advance,such that new resources are available when *** proposed architecture is implemented in OpenStack,extending the monitoring capabilities of Monasca by injecting short-term forecasts of standard *** use our architecture to implement predictive scaling policies leveraging on linear regression,autoregressive integrated moving average,feed-forward,and recurrent neural networks(RNN).Then,we evaluate their performance on a synthetic workload,comparing them to those of a traditional *** assess the ability of the different models to generalize to unseen patterns,we also evaluate them on traces from a real content delivery network(CDN)*** particular,the RNN model exhibites the best overall performance in terms of prediction error,observed client-side response latency,and forecasting *** implementation of our architecture is open-source.

关键词： OpenStack monitoring elasticity control auto-scaling predictive operations Monasca

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Compensation of friction in mechanical drives for a three fingered robot gripper

Compensation of friction in mechanical drives for a three fi...

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Proceedings of IEEE/RSJ International Conference on Intelligent Robots and systems. IROS '96

作者： T. Doersam P. Duerrschmied Department for Computer Science Institute for Real-Time Computer Systems and Robotics University of Karlsruhe Karlsruhe Germany

Performing fine manipulations with multifingered robot hands makes high demands on the control algorithms and the speed of the control computer. Mainly nonlinear friction problems and plant uncertainties require intensive fine-tuning of a controller. This paper gives insight into the frictional behaviour of geared finger links. The behaviour has been approximated by a friction model. Considering the estimated system parameters two kinds of controllers are developed: a simple PD controller with switchable I-part and a PD-controller with a fuzzy friction compensation working in parallel. The results of both controllers are presented and compared in this paper.

关键词： Friction Control systems Robots High performance computing Uncertainty Fingers Parameter estimation PD control Fuzzy control Fuzzy systems

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An Integrated Method for Planning Smooth Collision-Free Trajectories for Robot Arms

An Integrated Method for Planning Smooth Collision-Free Traj...

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Annual Conference of AI, Simulation, and Planning in High Autonomy Syslems

作者： Jianwei Zhang Institute for Real-Time Computer Systems and Robotics Faculty of Computer Science University of Karlsruhe Germany

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Control Schemes for Passive Teleoperation systems over Wide Area Communication Networks with time Varying Delay

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International Journal of Automation and computing 2014年第1期11卷 100-108页

作者： Shafiqul Islam Xiaoping P.Liu Abdulmotaleb El Saddik Lakmal Seneviratne Jorge Dias School of Information Technology and Engineering University of Ottawa School of Engineering and Applied Sciences Harvard University Robotics and Mechanical Engineering Khalifa University of Science & Technology Department of Systems and Computer Engineering Carleton University Electrical Engineering New York University Division of Engineering Kings College London Robotics and Electrical and Computer Engineering Khalifa University of Science & Technology Institute of Systems and Robotics University of Coimbra

In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is *** design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave *** adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave ***-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation *** stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote ***,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications.

关键词： Teleoperation telerobotics Lyapunov-Krasovskii functional time varying delay passive systems

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Efficient test suite reduction by merging Pairs of suitable test cases

Efficient test suite reduction by merging Pairs of suitable ...

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Lecture Notes in computer science

作者： Cichos, Harald Heinze, Thomas S. Real-time Systems Lab TU Darmstadt Darmstadt Germany Institute of Computer Science Friedrich Schiller University of Jena Jena Germany

ISBN: (纸本)9783642212093

During the development and maintenance of software, the size of a test suite often increases to such an extent that the costs allocated for its execution are exceeded. In this case, the test suite needs to be reduced. A number of approaches address the problem of test suite reduction. Most of them consider the removal or merging of test cases. However, less attention has been paid to the identification of test cases that are suitable for merging. In this paper, we present a novel approach to fill this gap. Using this approach allows for the identification of test case pairs that, when merged, have a high potential for test suite reduction. We show that two test suites reduced by our approach are considerably smaller in size than those, whose merged test cases were selected randomly. Additionally, we examine the effect of composite test goals on the reduction ratio. © 2011 Springer-Verlag Berlin Heidelberg.

关键词： Merging

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A parallel control computer structure for complex high speed applications

A parallel control computer structure for complex high speed...

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IEEE International Conference on Engineering of Complex computer systems

作者： B. Magnussen Institute for Real-Time Computer Systems and Robotics Faculty for Computer Science University of Karlsruhe Karlsruhe Germany

With high speed control applications it is often very difficult to achieve the aspired timing of the control algorithm using just one processor. This is true especially if the system is complex or very large. In this paper we discuss advantages and disadvantages of a new system architecture using many processors of which each one is specialised for one part of the algorithm. A tailorable parallel computer architecture which we developed to cope with the problems of parallelisation of control algorithms is presented. Finally examples from the field of robotics and the performance of the prototype computer is presented.

关键词： Concurrent computing Application software Control systems computer architecture Velocity control Hardware Communication system control Robot sensing systems computer science Timing

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WCET-aware static locking of instruction caches 12

WCET-aware static locking of instruction caches

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10th International Symposium on Code Generation and Optimization, CGO 2012

作者： Plazar, Sascha Kleinsorge, Jan C. Marwedel, Peter Falk, Heiko Department of Computer Science 12 TU Dortmund University D-44221 Dortmund Germany Institute of Embedded Systems/Real-Time Systems Ulm University D-89081 Ulm Germany

ISBN: (纸本)9781605586359

In the past decades, embedded system designers moved from simple, predictable system designs towards complex systems equipped with caches. This step was necessary in order to bridge the increasingly growing gap between processor and memory system performance. Static analysis techniques had to be developed to allow the estimation of the cache behavior and an upper bound of the execution time of a program. This bound is called worst-case execution time (WCET). Its knowledge is crucial to verify whether hard real-time systems satisfy their timing constraints, and the WCET is a key parameter for the design of embedded systems. In this paper, we propose aWCET-aware optimization technique for static I-cache locking which improves a program's performance and predictability. To select the memory blocks to lock into the cache and avoid time consuming repetitive WCET analyses, we developed a new algorithm employing integer-linear programming (ILP). The ILP models the worst-case execution path (WCEP) of a program and takes the inuence of locked cache contents into account. By modeling the effect of locked memory blocks on the runtime of basic blocks, the overall WCET of a program can be minimized. We show that our optimization is able to reduce the estimated WCET (abbr. WCETest) of real-life benchmarks by up to 40.8%. At the same time, our proposed approach is able to outperform a regular cache by up to 23.8% in terms of WCETest. Copyright © 2012 ACM.

关键词： Embedded systems

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Distributed control architecture for intelligent systems

Distributed control architecture for intelligent systems

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Midwest Symposium on Circuits and systems (MWSCAS)

作者： T. Laengle T.C. Lueth U. Rembold H. Woern Institute for Real-Time Computer Systems and Robotics Faculty for Computer Science University of Karlsruhe Karlsruhe Germany

In contrast to a hierarchical and centralized structure, distributed or decentralized control architectures reveal their main advantages when it is necessary to enhance the system, to integrate components, and to maintain the system. The main disadvantage of not centralized architectures is having to make sure that the system will fulfill an overall or global goal. To investigate these problems, a distributed control architecture for intelligent systems was developed at the University of Karlsruhe. In this paper, the methods for dead-lock-free coordination and cooperation are explained.

关键词： Distributed control Intelligent systems Intelligent control Robot kinematics computer architecture Intelligent robots real time systems computer science Intelligent manufacturing systems Resource management

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