Real-time Embedded Control Systems Research Articles

Verification of Safety for Synchronous-Reactive System Using Bounded Model Checking

Real-time embedded systems are increasingly applied in safety-critical areas, so guaranteeing the correctness of such systems by means of formal methods becomes particularly important. In this paper, we propose an optimized bounded model checking (BMC)-based formal verification approach for the verification of safety for synchronous-reactive (SR) models, which are often used to design systems with complicated control logic, especially the real-time embedded control systems. This method is based on the tackling of a series of challenging problems including the management of the logical clock, encoding of the contained ports, representation of the data types of ports, descriptions of behaviors of various components in a considered model, and formal consideration of the fixed-point semantics. We have implemented this proposed method in the prototype Ptolemy-Z3, and integrated this tool into the Ptolemy II environment. In addition, the experimental evaluation on 22 SR models has shown that our method performs better than the existing automatic verification method in Ptolemy II.

COTS-Based Real-Time System Development: An Effective Application in Pump Motor Control

The progress of embedded control systems in the last several years has made possible the realization of highly-effective controllers in many domains. It is essential for such systems to provide effective performance at an affordable cost. Furthermore, real-time embedded control systems must have low energy consumption, as well as be reliable and timely. This research investigates primarily the feasibility of implementing an embedded real-time control system, based on a low-cost, commercially off-the-shelf (COTS) microcontroller platform. It explores real-time issues, such as the reliability and timely response, of such a system implementation. This work presents the development and performance evaluation of a novel real-time control architecture, based upon a BeagleBoard microcontroller, and applied into the PWM (pulse width modulation) control of a three-phase induction motor in a suction pump. The approach followed makes minimal use of general-purpose hardware (BeagleBone Black microcontroller board) and open-source software components (including Linux Operating System with PREEMPT_RT real-time support) for building a reliable real-time control system. The applicability of the proposed control system architecture is validated and evaluated in a real case study in manufacturing. The results provide sufficient evidence of the efficiency and reliability of the proposed approach into the development of a real-time control system based upon COTS components.

A Tweakable Image Encryption Algorithm Using an Improved Logistic Chaotic Map

This paper presents component-based and aspect-oriented methodology and tool for designing and developing Real-Time Embedded Control Systems (RTECS). This methodology defines a component model for describing modular and reusable software to cope with the increasing complexity of embedded systems. It proposes an aspect-oriented approach to address explicitly the extra-functional concerns of RTECS, to describe separately transversal real time and security constraints, and to support model properties analysis. The benefits of this methodology are shown via an example of Legway control software, a version of the Segway vehicle built with Lego Mindstorms NXT. Keywords-Model-based design, software component, aspect-oriented programming, embedded system design, embedded control software.

Development of Real Time Embedded Control System for Transfer Arm Examination Facility in PFBR

Development of Real Time Embedded Control System for Transfer Arm Examination Facility in PFBR

Adaptive Assignment of Deadline and Clock Frequency in Real-Time Embedded Control Systems

Adaptive Assignment of Deadline and Clock Frequency in Real-Time Embedded Control Systems

A Real-Time Embedded Control System for Electro-Fused Magnesia Furnace

Since smelting process of electro-fused magnesia furnace is a complicated process which has characteristics like complex operation conditions, strong nonlinearities, and strong couplings, traditional linear controller cannot control it very well. Advanced intelligent control strategy is a good solution to this kind of industrial process. However, advanced intelligent control strategy always involves huge programming task and hard debugging and maintaining problems. In this paper, a real-time embedded control system is proposed for the process control of electro-fused magnesia furnace based on intelligent control strategy and model-based design technology. As for hardware, an embedded controller based on an industrial Single Board Computer (SBC) is developed to meet industrial field environment demands. As for software, a Linux based on Real-Time Application Interface (RTAI) is used as the real-time kernel of the controller to improve its real-time performance. The embedded software platform is also modified to support generating embedded code automatically from Simulink/Stateflow models. Based on the proposed embedded control system, the intelligent embedded control software of electro-fused magnesium furnace can be directly generated from Simulink/Stateflow models. To validate the effectiveness of the proposed embedded control system, hardware-in-the-loop (HIL) and industrial field experiments are both implemented. Experiments results show that the embedded control system works very well in both laboratory and industry environments.

Vision Based Tracking for a Quadrotor Using Vanishing Points

In this paper, a vision based line tracking control strategy for mini-rotorcraft is presented. In order to estimate the 3-D position of the mini-rotorcraft over the trajectory a vanishing points technique is used. A dynamic model is derived employing the Newton---Euler approach and a nonlinear controller to stabilize, in closed-loop system, this mathematical model is proposed. To validate the theoretical results, a real-time embedded control system has been developed. The performance of the vision and control algorithms has been tested when the helicopter has tracked a line painted in a wall. The experimental results have shown the good behavior of the control laws.

Vision Based Tracking for a Mini-Rotorcraft Using Vanishing Points

AbstractA vision based line tracking control strategy for a mini-rotorcraft is presented in this paper. The vision algorithm, employed to estimate the 3D position of the mini helicopter, is based on the vanishing points technique. Also, the dynamic model of this rotorcraft is presented in order to propose a nonlinear controller to navigate following a line. To validate the theoretical results, a real-time embedded control system has been developed. Experimental results have shown the good behavior of the proposed control vision scheme.

ASPECT-BASED METHODOLOGY FOR REAL-TIME EMBEDDED CONTROL SYSTEMS DESIGN

Designing real-time embedded control systems follows usually a V-process and requires various languages and tools. Each language/tool provides a design methodology, and defines its own terminology and semantic. This lack of consistency leads usually to a disconnected design process where the transformation of models is usually performed manually. Thus, errors may be introduced in the models. Correcting these errors lengthens the design lifecycle and time to market.In this paper, we propose a new methodology which aims to fill the gaps due to the lack of consistency by unifying the terminologies and semantics used, and reduces the time spent in translation and debugging. This methodology does not propose a new global language which is far from each domain concerns and where the leaning curve is longer. The goal is rather to provide a multi-facet design using aspect and component approaches, and relying on an unified system metamodel in order to link the semantic differences between control and real-time computing languages and tools.

Future Directions of Internet-based Control Systems

Recent advances in object-oriented, client/server technologies, and the Internet are supplying the technology enablers needed to provide a uniform information architecture that can be used to build software architecture allowing the inter-operation and integration of a wide set of diverse applications. Moreover the emerging standards start playing a significant role in the shaping of automation architectures in enterprises. The inclusion within a classical control system of Internet-related technologies and open distributed application concepts would give the present system compliance with current and future technological trends. At the present time, in the field of the industrial automation, real-time embedded control systems more and more need Internet connectivity for operations of remote plant administration, training, and supervisory activities. In this paper the state of the art in embedded control systems is presented within the field of industrial automation applications, and the technological scenario is discussed, followed by the trend for the evolution in process control systems. Guidelines for the design of innovative, thus competitive control systems are suggested. A case study is presented, outcome of an EC project in which one of the authors is involved, where a remote maintenance system is realized.

Data flow driven computer for embedded control systems

This paper discusses the approach taken towards the design of a real time embedded control system based on the dataflow concept applied to the industrial environment stimuli and control outputs while integrating the advantage of conventional, control-flow oriented programming up to the process-level (Section 1). The specific features of embedded control systems motivated the selection of a ring-type architecture composed of data distributor, set of executors and results collector (Section 2). The execution of a process, once fired, is fully independent of the environment. All the data needed during the execution are delivered in the packet associated with the firing token. To fire a process OR-ed dataflow tokens' relation has been adopted (Section 3). Section 4 discussed the stability criterium and measures taken to keep under control the explosive nature of OR-ed dataflow. The following section (Section 5) demonstrates an example and the feasibility of implementation of a certain control system deploying the computer under consideration. The computer has been assembled using standard components (Section 6) to facilitate the cost/performance evaluation of a conventional and dataflow concepts in a selected area of application. The paper concludes by summarizing the premises for a successfull deployment of the presented computer in the embeded control systems development (Section 7).