Automated Hard Real-Time Scheduling

Hybrid MultiGene Genetic Programming - Artificial neural networks approach for dynamic performance prediction of an aeroengine

We review practical case studies of a developing method of highly reliable real-time embedded control systems using a CPU model-based hardware/software co-simulation. We take an approach that enables us to fully simulate a virtual mechanical control system including a mechatronics plant, microcontroller hardware, and object code level software. This full virtual system approach simulates control system behavior, especially that of the microcontroller hardware and software. It enables design space exploration of microarchitecture, control design validation, robustness evaluation of the system, software optimization before components design. It also avoids potential problems. The advantage of this work is that it comprises all the components in a typical control system, enabling the designers to analyze effects from different domains, for example mechanical analysis of behavior due to differences in controller microarchitecture. To further improve system design, evaluation and analysis, we implemented an integrated behavior analyzer in the development environment. This analyzer can graphically display the processor behavior during the simulation without affecting simulation results such as task level CPU load, interrupt statistics, and the software variable transition chart. It also provides useful information on the system behavior. This virtual system analysis does not require software modification, does not change the control timing, and does not require any processing power from the target microcontroller. Therefore this method is suitable for real-time embedded control system design, in particular automotive control system design that requires a high level of reliability, robustness, quality, and safety. In this study, a Renesas SH-2A microcontroller model was developed on a CoMET™platform from VaST Systems Technology. An electronic throttle control (ETC) system and an engine control system were chosen to prove this concept. The electronic throttle body (ETB) model on the Saber® simulator from Synopsys® and the engine model on MATLAB®/Simulink®simulator from MathWorks can be simulated with the SH-2A model using a newly developed co-simulation interface between MATLAB®/Simulink® and CoMET™. Though the SH-2A chip was being developed as the project was being executed, we were able to complete the OSEK OS development, control software design, and verification of the entire system using the virtual environment. After releasing a working sample chip in a later stage of the project, we found that such software could run on both actual ETC system and engine control system without critical problem. This demonstrates that our models and simulation environment are sufficiently credible and trustworthy.

The performance of a networked control system (NCS) is affected directly and indirectly by time delays generated in network communication. This paper addresses these time delays, their effects on system performance and the measures taken in an NCS design. For a time delay that is random but less than one sampling interval T, we model the system as a time-invariant control system with constant time delay T. For a time delay that is random and greater than one sampling interval T, we consider the system as a control system with packet drop and model it as a jump linear control system. Based on the above models, we propose a systematic method to improve the control system quality of performance by choosing a proper sampling interval to reduce data transmission, optimally scheduling to minimise packet loss and optimising controller design in case of packet loss. The simulation results and lab experiments demonstrate that the design method results in high performance in networked real-time control system.

Towards the conceptual design of the ITER real-time plasma control system

This paper explains the design of real-time control system for control of drives containing the artificial muscles. Described is the design of hardware and software devices, as well as design of their involvement in the experimental device. In this paper are referred experimental measurements on the device, aimed at monitoring the change in observed characteristics caused by position changes in artificial muscles during their operation.

In this paper, Linux-RTAI and Matlab/RTW is used to develop real-time control system for fast real-time simulation and implementation of the control algorithm. The hardware of the controller is based on PC/104 cards under Linux-RTAI operating system. The main characteristic of Matlab/RTW is that it can automatically generate the real-time simulation code for many target processors. The combination of Linux-RTAI as a controller platform and Matlab/RTW as control algorithm development environment brings the two main advantages: hard real-time capability and reduced time for control development. Moreover, online signal monitor and parameter modification is realized on the whole structure system. At last, the minimum execution time of real-time control task is determined and the application of real-time control system into flight vehicle is achieved in the work.

This paper describes the design and implementation of an OMAP3530-based networked control system which has real-time image processing capability. It integrates an ARM core and a DSP core in the controller. The ARM core with Linux operating system is responsible for applying functional services and the DSP core is responsible for executing image processing algorithms. The due-core structure makes the novel controller available for advanced control and image processing so that the designed control system expands the application of the existed networked controllers to machine vision. Finally, a reliable application for vision-based mobile robot localization demonstrates the effectiveness of the designed system.

This paper examines a class of real-time control systems in which each control task triggers its next release based on the value of the last sampled state. Prior work used simulations to demonstrate that self-triggered control systems can be remarkably robust to task delay. This paper derives bounds on a task's sampling period and deadline to quantify how robust the control system's performance will be to variations in these parameters. In particular we establish inequality constraints on a control task's period and deadline whose satisfaction ensures that the closed-loop system's induced L 2 gain lies below a specified performance threshold. The results apply to linear time-invariant systems driven by external disturbances whose magnitude is bounded by a linear function of the system state's norm. The plant is regulated by a full-information H infin controller. These results can serve as the basis for the design of soft real-time systems that guarantee closed-loop control system performance at levels traditionally seen in hard real-time systems.

Real-time active control of RFX-mod plasma equilibrium

The Graduate Automotive Technology Education (GATE) Center at the University of Tennessee, Knoxville (UTK) offers courses addressing the simulation, modeling, and control system design of hybrid electric vehicles (HEV). In the Spring of 1999 such a course was conducted to support the UTK FutureCar Challenge entry for 1999. The vehicle modeled is a Dual-configuration Hybrid Electric Vehicle (DHEV) which uses a planetary power-split device similar to the Toyota Hybrid System used in the Toyota “Prius”. The goals of the course included the development of a real-time simulator that could incorporate actual vehicle control hardware in the simulator loop. This “control-hardware-in-the-loop” (CHIL) configuration was used for simulation, control system design, and troubleshooting. This approach allows the simulation of normal vehicle operating conditions as well as emergency fault handling situations in which it may not be desirable to subject the actual prototype vehicle to a given test condition. Additionally, it is possible to do a great deal of control system testing and development without an operating vehicle.

Due to the real-time requirements of the manipulators control, the dedicated control systems are required, which has the disadvantages of the high cost, complexity and lack of flexibility. The control software cannot be modified according to the user's expectation in the application of new algorithms or secondary development for the close framework. To overcome the above shortcomings, the paper is to construct an open architecture manipulator host control system based on the traditional Windows system by extending RTX. The host control system communicates with the manipulators by the high serial data bus. Most of the control algorithms of the manipulator run on the host control system, and the vector control of the motor is located in the joint. Experiment results indicate that the RTX system achieves the deterministic control of the manipulator with high real-time performance on the same computer, takes the advantage of rapid prototype development of software, open architecture, better compatibility and real-time performance, which improves the efficiency in the development of manipulator and the application of new control algorithms.

Algorithms, software and hardware of parallel computers: J Mikloško and V E Kotov (eds)Springer-Verlag, Berlin, FRG (1984) DM 89 pp 395

During laser micro-machining, the constant control of laser energy density is a key technology to improve the processing precision. This paper presents a laser spot size of real-time detection and control system design on the base CCD and FPGA processing technology. Using CCD video signal binarization method and FPGA processing technology, we realized real time detection and control of spot area on the workpiece to achieve a constant purpose. The relative measurement error of spot size is very small as maximum 0.5 percent, the resolution of spot size measurement is less than 10μm2. This system can be directly applied to control of laser spot in laser micro-polishing.

In this paper, we describe two general models for designing real-time distributed manufacturing control systems based on the IEC61499 (function block) standard. In order to construct IEC61499 function blocks, each model utilises UML capsules within an object-oriented framework. In the first model we treat a function block as a single capsule, while in the second we model the function block as a component containing multiple capsules. The key difference between these two viewpoints is the granularity of control we have over the function block's operation and its location within the decentralised manufacturing environment. We also evaluate the merits of these two viewpoints using a discrete-event simulation experimental test bed.

Design of a fast real-time LPV model predictive control system for semi-active suspension control of a full vehicle