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IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA)

作者： J. Kreuzinger A. Schulz M. Pfeffer T. Ungerer U. Brinkschulte C. Krakowski Institute for Computer Design and Fault Tolerance University of Karlsruhe Karlsruhe Germany Institute for Process Control Automation and Robotics University of Karlsruhe Karlsruhe Germany

This paper investigates real-time scheduling algorithms on upcoming multithreaded processors. As evaluation testbed we introduce a multithreaded processor kernel which is specifically designed as core processor of a micro-controller or system-on-a-chip. Handling of external real-time events is performed through multithreading. Real-time threads are used as interrupt service threads (ISTs) instead of interrupt service routines (ISRs). Our proposed micro-controller supports multiple ISTs with zero-cycle context switching overhead. We investigate the behavior of fixed priority preemptive, earliest deadline first, least laxity first and guaranteed percentage scheduling with respect to multithreaded processors. Our finding is that the strategies GP and LLF result in a good blending of instructions of different threads thus enabling a multithreaded processor to utilize latencies best. Assuming a zero-cycle context switch LLF performs best, however implementation cost context, are prohibitive.

关键词： processor scheduling Yarn Switches Scheduling algorithm System testing Kernel process design System-on-a-chip Multithreading Delay

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A multithreaded Java microcontroller for thread-oriented real-time event-handling

A multithreaded Java microcontroller for thread-oriented rea...

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International Conference on Parallel Architecture and Compilation Techniques (PACT)

作者： U. Brinkschulte C. Krakowski J. Kreuzinger T. Ungerer Institute of Process Control Automation and Robotics University of Karlsruhe Karlsruhe Germany Institute of Computer Design and Fault Tolerance University of Karlsruhe Karlsruhe Germany

We propose a multithreaded Java microcontroller (called Komodo microcontroller) with a new hardware event handling mechanism that allows handling of simultaneous overlapping events with hard real-time requirements. Real-time Java threads are used as interrupt service threads (ISTs) instead of interrupt service routines (ISRs). Our proposed Komodo microcontroller supports multiple ISTs with zero-cycle context switching overhead. We evaluate the basic architectural attributes using real-time event parameters of an autonomous guided vehicle. When calculating the maximum vehicle speed without violating the real-time constraints, ISTs dominate ISRs by a speed increase of 28%.

关键词： Java Microcontrollers Switches Embedded system Yarn Application software Real time systems Hardware Multithreading process control

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Finite-time asynchronous dissipative filtering of conic-type nonlinear Markov jump systems

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Science China(Information Sciences) 2021年第5期64卷 151-162页

作者： Xiang ZHANG Shuping HE Vladimir STOJANOVIC Xiaoli LUAN Fei LIU Key Laboratory of Intelligent Computing and Signal Processing (Ministry of Education) School of Electrical Engineering and Automation Anhui University Department of Automatic Control Robotics and Fluid Technique Faculty of Mechanical and Civil EngineeringUniversity of Kragujevac Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education) Institute of AutomationJiangnan University

In the present study, the finite-time asynchronous dissipative filter design problem for the Markov jump systems with conic-type nonlinearity is studied. The hidden Markov model can describe the asynchronism embodied in the system modes and the filter modes reasonably. Moreover, a suitable LyapunovKrasovskii function is utilized and linear matrix inequalities are applied to obtain adequate conditions. These techniques guarantee the finite-time boundedness and strict dissipativity of the filtering error dynamic system. Furthermore, the design problems of the passive filter and the H∞ filter are studied by adjusting the three parameters U, G and V. Finally, the filter gains and the optimal index α*are obtained and the correctness and feasibility of the designed approach are verified by a simulation example.

关键词： dissipative filtering hidden Markov model finite-time boundedness Markov jump systems conic-type nonlinearity

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Research on the ground control system of quadrotor unmanned aerial vehicles

Research on the ground control system of quadrotor unmanned ...

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World Congress on Intelligent Control and automation (WCICA)

作者： Tingting Zhao Bin Xian Yungao Yang Fang Guo Guoping Huang The Institute of Robotics and Autonomous System the Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University 300072 China

The quadrotor unmanned aerial vehicle (UAV) has been a focus for unmanned aerial vehicles. Ground control system (GCS) is an important part of the quadrotor UAV flight control system, and it can promote the flight performance and safety of quadrotor UAVs. In this paper, a quadrotor UAV GCS is designed and implemented, and the GCS realizes the following functions, including receiving and storing of the flight data, the real-time localization utilizing the customization of electronic maps like MapX and Google Earth, the visual display of flight states via virtual instruments and the waypoint planning. Outdoor experiments have been done to verify the GCS's performance. It can be concluded that the proposed GCS in this paper can work stably, and it can guarantee the integrity of the flight data, the accuracy of the instruments display and map localization.

关键词： Google Earth Sockets Unmanned aerial vehicles XML HTML automation

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Autonomous hovering control for a quadrotor unmanned aerial vehicle

Autonomous hovering control for a quadrotor unmanned aerial ...

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Chinese Control Conference (CCC)

作者： Fu Wang Bin Xian Guoping Huang Bo Zhao The Institute of Robotics and Autonomous System the Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University 300072 China

In this paper, an autopilot system for the quadrotor unmanned aerial vehicle (UAV) is developed by utilizing a digital signal processor (DSP) as the on-board micro-control unit (MCU). The hardware setup and the software are also developed for the autonomous flight control of the UAV. The main design procedure includes the controller board design, brushless DC motor driver design, sensor data processing software design, and flight control algorithm design. The control algorithm is developed based on the inner loop and outer loop control method. Proportional Derivative (PD) controllers are proposed for the attitude dynamics (inner loop) and position dynamics (outer loop) respectively. Autonomous hovering control is achieved via the control of roll angle, pitch angle, yaw angle and altitude of the UAV. Experiments results are included to demonstrate the hovering control performance.

关键词： Digital signal processing Pulse width modulation Electronic mail Unmanned aerial vehicles Educational institutions Digital signal processors Heuristic algorithms

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Development of a three degree-of-freedom testbed for an unmanned helicopter and attitude control design

Development of a three degree-of-freedom testbed for an unma...

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Chinese Control Conference (CCC)

作者： Jianchuan Guo Bin Xian Fu Wang Xu Zhang The Institute of Robotics and Autonomous System Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University 300072 China

To provide a safe and efficient test for the autonomous control design of the unmanned helicopter, a 3 degree-of-freedom (DOF) helicopter testbed is developed in this paper. The testbed uses a small electric hobby helicopter as the main body, a digital signal processsor (DSP) is employed as the on-board micro control unit (MCU) for the attitude control of the helicopter, a micro attitude and heading reference system (AHRS) is utilized as the main on-board sensor for attitude states feedback and a Bluetooth module is mounted on the testbed to provide realtime wireless communication between the helicopter and the ground control station (GCS). This paper investigates the servo actuators coordinated control method with separate channel of the new-style electric helicopter, which is named as electronic collective-cyclic pitch mixing (ECCPM). A modified digital incremental PID control algorithm which is free of servo actuators saturation issue is proposed for the attitude control of the helicopter. Finally, experiment results are provided to verify the testbed and control design.

关键词： Helicopters Digital signal processing Attitude control Electronic mail process control Educational institutions Control design

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Hazard Analysis of Collaborative automation Systems: A Two-layer Approach based on Supervisory Control and Simulation

Hazard Analysis of Collaborative Automation Systems: A Two-l...

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IEEE International Conference on robotics and automation (ICRA)

作者： Tom P. Huck Yuvaraj Selvaraj Constantin Cronrath Christoph Ledermann Martin Fabian Bengt Lennartson Torsten Kröger Intelligent Process Automation and Robotics Lab Institute of Anthropomatics and Robotics (IAR-IPR) Karlsruhe Institute of Technology India Department of Electrical Engineering Division of Systems and Control Chalmers University of Technology Gothenburg Sweden

Safety critical systems are typically subjected to hazard analysis before commissioning to identify and analyse potentially hazardous system states that may arise during operation. Currently, hazard analysis is mainly based on human reasoning, past experiences, and simple tools such as checklists and spreadsheets. Increasing system complexity makes such approaches decreasingly suitable. Furthermore, testing-based hazard analysis is often not suitable due to high costs or dangers of physical faults. A remedy for this are model-based hazard analysis methods, which either rely on formal models or on simulation models, each with their own benefits and drawbacks. This paper proposes a two-layer approach that combines the benefits of exhaustive analysis using formal methods with detailed analysis using simulation. Unsafe behaviours that lead to unsafe states are first synthesised from a formal model of the system using Supervisory Control Theory. The result is then input to the simulation where detailed analyses using domain-specific risk metrics are performed. Though the presented approach is generally applicable, this paper demonstrates the benefits of the approach on an industrial human-robot collaboration system.

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Fault-tolerant control of an electro-hydraulic servo axes with a duplex-valve-system *

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IFAC Proceedings Volumes 2011年第1期44卷 9425-9433页

作者： Beck Mark Schwung Andreas Muenchhof Marco Isermann Rolf TU Darmstadt Institute of Automatic Control Laboratory for Control Systems and Process automation 64283 Darmstadt Germany TU Darmstadt Institute of Automatic Control Laboratory for Control Theory and Robotics 64283 Darmstadt Germany

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.

关键词： Fault Detection Fault Diagnosis Fault Tolerance Electro-hydraulic Servo Axes Duplex-valve-system Active Fault-Tolerant Control Reconfiguration Bumpless-Transfer

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Experimental study of odometry estimation methods using RGB-D cameras

Experimental study of odometry estimation methods using RGB-...

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2014 IEEE/RSJ International Conference on Intelligent Robots and Systems

作者： Zheng Fang Sebastian Scherer State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang China Robotics Institute Carnegie Mellon University Pittsburgh PA USA

Lightweight RGB-D cameras that can provide rich 2D visual and 3D point cloud information are well suited to the motion estimation of indoor micro aerial vehicles (MAVs). In recent years, several RGB-D visual odometry methods which process data from the sensor in different ways have been proposed. However, it is unclear which methods are preferable for online odometry estimation on a computation-limited, fast moving MAV in practical indoor environments. This paper presents a detailed analysis and comparison of several state-of-the-art real-time odometry estimation methods in a variety of challenging scenarios, with a special emphasis on the trade-off among accuracy, robustness and computation speed. An experimental comparison is conducted using public available benchmark datasets and author-collected datasets including long corridors, illumination changing environments and fast motion scenarios. Experimental results present both quantitative and qualitative differences among these methods and provide some guidelines on choosing the “right” algorithm for an indoor MAV according to the quality of the RGB-D data and environment characteristics.

关键词： Three-dimensional displays Visualization Cameras Feature extraction Estimation Iterative closest point algorithm Robustness

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Nonlinear Asymptotic Attitude Tracking Control for an Unmanned Helicopter with Input Constraints

Nonlinear Asymptotic Attitude Tracking Control for an Unmann...

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American Control Conference

作者： Xiang Liu Bin Xian Yao Zhang Xu Zhang Institute of Robotics and Autonomous System the Tianjin Key Laboratory of Process Measurement and Control Schoool of Electrical Engineering and Automation Tianjin University Tianjin 300072 China

ISBN: (纸本)9781479932757

In this paper a nonlinear attitude tracking control scheme is developed for a small-scaled unmanned helicopter under input constraints. Via the analysis of the properties associated with the helicopter's rotor dynamics, the elevator servo input, the aileron servo input, and the rudder servo input are chosen to be the control inputs to be designed. Their constraints in amplitude under hovering flight is taken into account by using the robust bounded terms in the controller design. The asymptotic convergence of the tracking error is guaranteed with the Lyapunov-based stability analysis.

关键词： Helicopters Rotors Attitude control Vectors Servomotors Stability analysis Equations

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