Abstract This paper presents fault detection, fault diagnosis, the fault-tolerant control of an electro-hydraulic servo axes with a duplex-valve-system. The fault detection is based on parity equations and is load ind...
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Abstract This paper presents fault detection, fault diagnosis, the fault-tolerant control of an electro-hydraulic servo axes with a duplex-valve-system. The fault detection is based on parity equations and is load independent. The semi-physical models allow the detection of even small faults in the hydraulic system. The fault diagnosis used at the testbed is based on fuzzy-logic. In order to tolerate a faulty hydraulic proportional valve, a duplex-valve-system built up with standard proportional valves is applied. The fault management module allows the supervision of the hydraulic servo axes and decides on the reconfiguration of the control-loop. An Internal Model control (IMC)-tracking control structure for bumpless transfer between controllers is presented. Experimental results show the industrial applicability of the approach.
For a ground target tracking system using an unmanned helicopter, an on-board pan-tilt controller is proposed to adjust the attitude of the camera, so that to keep the target staying at the center of the image plane w...
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For a ground target tracking system using an unmanned helicopter, an on-board pan-tilt controller is proposed to adjust the attitude of the camera, so that to keep the target staying at the center of the image plane when the target is in sight. When the target is temporarily out of view due to various reasons, the designed controller will make the camera quickly re-capture the target by estimating its state and then regulating the orientation of the camera correspondingly. Specifically, a novel state transformation is firstly introduced to make the error system independent of the target image. Subsequently, a nonlinear pan-tilt controller is designed for the transformed error system. Lyapunov techniques are then employed to prove that the target tracking error in the image plane is driven to zero exponentially fast. To facilitate the implementation of the constructed controller, a visual estimator is also utilized to obtain the state information of the target even if it is occasionally out of the view of the camera by introducing an effective nonlinear filter. Simulation results are provided to validate the performance of the presented control system.
In this paper fault detection, fault diagnosis and active fault tolerant control of an electro-hydraulic servo-axis with a duplex-valve-system are described. The fault detection is based on parity equations. The semi-...
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This paper introduces a novel tactile sensor with the ability to detect objects in the sensor's near proximity. For both tasks, the same capacitive sensing principle is used. The tactile part of the sensor provide...
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This paper introduces a novel tactile sensor with the ability to detect objects in the sensor's near proximity. For both tasks, the same capacitive sensing principle is used. The tactile part of the sensor provides a tactile sensor array enabling the sensor to gather pressure profiles of the mechanical contact area. Several tactile sensors have been developed in the past. These sensors lack the capability of detecting objects in their near proximity before a mechanical contact occurs. Therefore, we developed a tactile proximity sensor, which is able to measure the current flowing out of or even into the sensor. Measuring these currents and the exciting voltage makes a calculation of the capacitance coupled to the sensor's surface and, using more sensors of this type, the change of capacitance between the sensors possible. The sensor's mechanical design, the analog/digital signal processing and the hardware efficient demodulator structure, implemented on a FPGA, will be discussed in detail.
作者：
Beck MarkSchwung AndreasMuenchhof MarcoIsermann RolfTU Darmstadt
Institute of Automatic Control Laboratory for Control Systems and Process automation 64283 Darmstadt Germany (Tel: +49-6151-162314) TU Darmstadt
Institute of Automatic Control Laboratory for Control Theory and Robotics 64283 Darmstadt Germany (Tel: +49-6151-166283) TU Darmstadt
Institute of Automatic Control Laboratory for Control Systems and Process automation 64283 Darmstadt Germany (Tel: +49-6151-163114) TU Darmstadt
Institute of Automatic Control Laboratory for Control Systems and Process automation 64283 Darmstadt Germany (Tel: +49-6151-162114)
In this paper fault detection, fault diagnosis and active fault tolerant control of an electro-hydraulic servo-axis with a duplex-valve-system are described. The fault detection is based on parity equations. The semi-...
详细信息
In this paper fault detection, fault diagnosis and active fault tolerant control of an electro-hydraulic servo-axis with a duplex-valve-system are described. The fault detection is based on parity equations. The semi-physical models allow the detection of even small faults in the hydraulic system. The fault diagnosis used on the testbed is based on fuzzy-logic. In order to tolerate a failed hydraulic proportional valve, a duplex-valve-system built up with standard direct-driven proportional valves is applied. The fault management module allows the supervision of the hydraulic servo axis and decides on reconfiguration and fault accomodation of the control-loop. The Internal Model control (IMC)-tracking control structure used for reconfiguration allows bumpless transfer between controllers. Experimental results show the industrial applicability of the approach.
In this paper we propose a new diversity measure based on the correlation of bit strings for the analysis of genetic programming (GP) experiments. The diversity measure has been applied to analyse the impact of prunin...
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In this paper we propose a new diversity measure based on the correlation of bit strings for the analysis of genetic programming (GP) experiments. The diversity measure has been applied to analyse the impact of pruning on the diversity of a population during genetic programming and its relation to the convergence time of the fitness function. To show the usability of the proposed diversity measure a GP experiment is introduced where simulated Jasmine robots have to learn a collision avoidance behaviour to find their way through a maze. A full analysis of this experiment is given with different fixed pruning strategies in respect to the population diversity and fitness. The GP has been done on behaviour-based robot controllers implemented in MDL2isin. MDL2isin has the advantage that it provides a very compact bit string representation of the control programme, which can be used for diversity analysis.
Our aim is to investigate if it is possible to control the throughput (IPC rate) of a thread running on a simultaneous multi-threaded microprocessor by a closed feedback loop. We showed in previous experimental studie...
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ISBN:
(纸本)9780769531328
Our aim is to investigate if it is possible to control the throughput (IPC rate) of a thread running on a simultaneous multi-threaded microprocessor by a closed feedback loop. We showed in previous experimental studies that the proposed approach works. In this paper we discuss the control theory approach from a theoretical point of view. We develop a mathematical model of a general purpose multi-threaded microprocessor enhanced with a closed feedback controller and use control theory methods to investigate properties like stability and settling time.
作者：
F.L. LewisDept. of Electical Engineering
The University of Texas at Arlington U.S.A. F. L. Lewis was born in Wärzburg. Germany
subsequently studyning in Chile and Goruonstoun School in Scotland. He obtained the Bachelor's Degree in Physics/Electrical Engineering and the Master's of Electrical Engineering Degree at Rice University in 1971. He spent six years in the U.S. navy serving as Navigator aboard the frigate USS Trippe (FF-1075) and Executive Officer and Acting Commanding Officer aboard USS Salinan (ATF-161). In 1977 he received the Master's of Science in Aeronautical Engineering from the University of West Florida. In 1981 he obtained the Ph.D. degree at The Georgia Institute of Technology in Atlanta where he was employed as a professor from 1981 to 1990 and is currently an Adjunct Professor. He is a Professor of Electrical Engineering at The University of Texas at Arlington where he was awarded the Moncrief-O'Donnell Endowed Chair in 1990 at the Automation and Robotics Research Institute. Dr. Lewis has studied the geometric analytic and structural properties of dynamical systems and feedback control automation. His current interests include robotics intelligent control neural and fuzzy systes nonlinear systems and manufacturing process control. He is the author/co-author of 2 U.S. patents 124 journal papers 20 chapters and encyclopedia articles 210 refereed conference papers seven books: Optimal Control Optimal Estimation Applied Optimal Control and Estimation Aircraft Control and Simulation Control of Robot Manipulators Neural Network Control High-Level Feedback Control with Neural Networks and the IEEE reprint volume Robot Control. Dr. Lewis is a registered Professional Engineer in the State of Texas and was selected to the Editorial Boards of International Journal of Control Neural Computing and Applications and Int. J. Intelligent Control Systems. He is the recipient of an NSF Research Initiation Grant and has been continuously funded by NSF since 1982. Since 1991 he has received $1.8 m
A framework is given for controller design using Nonlinear Network Structures, which include both neural networks and fuzzy logic systems. These structures possess a universal approximation property that allows them t...
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A framework is given for controller design using Nonlinear Network Structures, which include both neural networks and fuzzy logic systems. These structures possess a universal approximation property that allows them to be used in feedback control of unknown systems without requirements for linearity in the system parameters or finding a regression matrix. Nonlinear nets can be linear or nonlinear in the tunable weight parameters. In the latter case weight tuning algorithms are not straightforward to obtain. Feedback control topologies and weight tuning algorithms are given here that guarantee closed-loop stability and bounded weights. Extensions are discussed to force control, backstepping control, and output feedback control, where dynamic nonlinear nets are required.
This paper presents a real-time Java hardware and software system for use in embedded applications. The system includes a multithreaded Java microcontroller, an adapted Java Virtual Machine (JVH) and an extended appli...
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This paper presents a real-time Java hardware and software system for use in embedded applications. The system includes a multithreaded Java microcontroller, an adapted Java Virtual Machine (JVH) and an extended application programming interface (API). The microcontroller core is designed with a multithreaded pipeline and hardware support for real-time scheduling algorithms. The Java Virtual Machine consists of trap routines for complex Java byte-codes, real-time garbage collection and a class loader for creating real-time data structures. On a higher level, the application programming interface provides easy real-time thread management and access to hardware components like serial interfaces and timer/counter units.
The manipulation of large CT datasets needs fast visualisation methods for a comfortable user interaction. Modern visualisation techniques make use texture hardware in graphics workstations extensively. In the followi...
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ISBN:
(纸本)1586030140
The manipulation of large CT datasets needs fast visualisation methods for a comfortable user interaction. Modern visualisation techniques make use texture hardware in graphics workstations extensively. In the following we will present an interactive tool for the positioning of anatomical landmarks in CT datasets of non-pathological children. The tool includes a fast visualisation of CT cross sections based on a texture mapping technique and an interactive three-dimensional view of the segmented CT dataset.
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