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  • 1.
    Aittamaa, Simon
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Lindgren, Per
    Uniform scheduling of internal and external events under SRP-EDF2010Ingår i: Annual International Conference on Real-Time and Embedded Systems ( RTES 2010): 1-2 November 2010, Mandarin Orchard Hotel, Singapore, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    With the growing complexity of modern embedded real-time systems, scheduling and managing of resources has become a daunting task. While scheduling and resource management for internal events can be simplified by adopting a commonplace real-time operating system (RTOS), scheduling and resource management for external events are left in the hands of the programmer, not to mention managing resources across the boundaries of external and internal events. In this paper we propose a unified system view incorporating earliest deadline first (EDF) for scheduling and stack resource policy (SRP) for resource management. From an embedded real-time system view, EDF+SRP is attractive not only because stack usage can be minimized, but also because the cost of a pre-emption becomes almost as cheap as a regular function call, and the number of preemptions is kept to a minimum. SRP+EDF also lifts the burden of manual resource management from the programmer and incorporates it into the scheduler. Furthermore, we show the efficiency of the SRP+EDF scheme, the intuitiveness of the programming model (in terms of reactive programming), and the simplicity of the implementation.

  • 2.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Embedded real-time software using TinyTimber: reactive objects in C2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Embedded systems are often operating under hard real-time constraints. Such systems are naturally described as time-bound reactions to external events, a point of view made manifest in the high-level programming and systems modeling language Timber. In this licensiate thesis we demonstrate how the Timber semantics for parallel reactive objects translates to embedded real-time programming in C. This is accomplished through the use of a minimalistic Timber Run-Time system, TinyTimber. The TinyTimber kernel ensures state integrity, and performs scheduling of events based on given time-bounds in compliance with the Timber semantics. In this way, we avoid the volatile task of explicitly coding parallelism in terms of traditional processes/threads/semaphores/monitors, and side-step the delicate task to encode time-bounds into process/thread priorities. Moreover, a simulation environment is developed that enables the behaviour of a heterogeous distributed system, consisting of both the hardware and the Timber based embedded software to be observed under a model of the environment. Furthermore, pedagogic issues of reactive objects have been studied in the context of higher education. First results indicate that the use of TinyTimber give students an increased ability to understand and solve embedded programming assignments. Finally, the TinyTimber kernel implementation is discussed. Performance metrics are given for a number of representative platforms, showing the applicability of TinyTimber to small embedded systems. A comparison to a traditional system tick driven, thread based, real-time kernel shows that TinyTimber provides tighter timing and a simpler (yet comprehensive) API. In conclution we find that the use of Reactive Objects in C, realized through TinyTimber is a viable alternative for Embedded Real-Time Programming.

  • 3.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Enabling Reactive Design of Robust Real-Time Embedded Systems2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
  • 4.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wiklander, Jimmie
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pietrzak, Pawel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    SRP-DM scheduling of component-based embedded real-time software2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Model and component based design is an established means for the development of large software systems, and is starting to get momentum in the realm of embedded software development. In case of safety critical (dependable systems) it is crucial that the underlying model and its realization captures the requirements on the timely behavior of the system, and that these requirements can be preserved and validated throughout the design process (from specification to actual code execution). To this end, we base the presented work on the notion of Concurrent Reactive Objects (CRO) and their abstraction into Reactive Components.In many cases, the execution platform puts firm resource limitations on available memory and speed of computations that must be taken into consideration for the validation of the system.In this paper, we focus on code synthesis from the model, and we show how specified timing requirements are preserved and translated into scheduling information. In particular, we present how ceiling levels for Stack Resources Policy (SRP) scheduling and analysis can be extracted from the model. Additionally, to support schedulability analysis, we detail algorithms that for a CRO model derives periods (minimum inter-arrival times) and offsets of tasks/jobs. Moreover, the design of a micro-kernel supporting cooperative hardware- and software-scheduling of CRO based systems under Deadline Monotonic SRP is presented.

  • 5.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Häggström, Fredrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Kruglyak, Andrey
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Real-time for the masses: Step 1: programming API and static priority SRP kernel primitives2013Ingår i: 2013 8th IEEE International Symposium on Industrial and Embedded Systems (SIES 2013): 19-21 June 2013, Porto, Portugal, Piscataway, NJ: IEEE Communications Society, 2013, s. 110-113Konferensbidrag (Refereegranskat)
    Abstract [en]

    Lightweight Real-Time Operating Systems have gained widespread use in implementing embedded software on lightweight nodes. However, bare metal solutions are chosen, e.g., when the reactive (interrupt-driven) paradigm better matches the programmer’s intent, when the OS features are not needed, or when the OS overhead is deemed too large. Moreover, other approaches are used when real-time guarantees are required. Establishing real-time and resource guarantees typically requires expert knowledge in the field, as no turn-key solutions are available to the masses.In this paper we set out to bridge the gap between bare metal solutions and traditional Real-Time OS paradigms. Our goal is to meet the intuition of the programmer and at the same time provide a resource-efficient (w.r.t. CPU and memory) implementation with established properties, such as bounded memory usage and guaranteed response times. We outline a roadmap for Real-Time For the Masses (RTFM) and report on the first step: an intuitive, platform-independent programming API backed by an efficient Stack Resource Policy-based scheduler and a tool for kernel configuration and basic resource and timing analysis.

  • 6.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A comprehensive approach to design of embedded real-time software for controlling mechanical systems2007Ingår i: Asia Pacific Automotive Engineering Conference Technical Papers, Society of Automotive Engineers, Incorporated , 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present a comprehensive approach to design of embedded real-time software for electrically controlled mechanical systems in automotive applications. As a case study, we implement a Gear change and Clutch controller for a Formula SAE car. This includes a generic communication interface and protocol for CAN bus communication, I/O interfaces for A/D conversion and PWM output, together with a PID controller for clutch actuation. Under our framework, the embedded software is developed using Timber, a programming language and formalism that provides executable models for embedded real-time systems. The case study shows how a complete control system can be straightforwardly modeled, simulated and transformed into executable code. The system has been realized and tested onto a lightweight, 8-bit AVR-5, embedded platform. Compared to the raw C code design flow, the proposed framework has in our case study showed increased efficiency with respect to development time. We boldly conclude that our Timber based framework offers true "work with the work".

  • 7.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    van Deventer, Jan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    A distributed engine management system for formula SAE2007Ingår i: Electronic Engine Controls: [held during the SAE 2007 world congress, April 16 - 19, 2007, Cobo Center, Detroit, MI, USA], Warrendale, Pa: Society of Automotive Engineers, Incorporated , 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper a distributed system for engine management is presented. The system is in use on the 2006 and 2005 Formula SAE cars from Luleå University of Technology. The purpose of building such a system from scratch is to have a comprehensive, predictable and easily extendable platform, giving the possibility to add extra features even at the racetrack. This allows the system to serve as a research platform for embedded real-time systems and vehicle dynamics. Another motivation is to get low weight on the complete system, and to integrate the electronics in such a way that the total cabling required will be minimal. The initial requirements are that the system should implement launch control, traction control, electric gear shift and clutch control. To control the engine the system must implement sequential fuel injection, direct fire ignition and closed loop lambda control. Moreover to remotely tune and monitor the system parameters in real-time - even on the racetrack, the system should facilitate wireless communication. To achieve these goals a system consisting of five units communicating over a standard automotive bus (CAN1) was developed. In this paper we will describe the systems functionality and the units developed.

  • 8.
    Eriksson, Johan
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nybacka, Mikael
    Larsson, Tobias
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Using Timber in a multi-body design environment to develop reliable embedded software2008Ingår i: Intelligent vehicle iniative (IVI) technology controls and navigation systems, 2008: [held during the SAE 2008 world congress, held April 14 - 17, 2008 in Detroit, Michigan, USA], Warrendale, Pa.: Society of Automotive Engineers, Incorporated , 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    A major challenge for the automotive industry is to reduce the development time while meeting quality assessments for their products. This calls for new design methodologies and tools that scale with the increasing amount and complexity of embedded systems in today's vehicles.In this paper we undertake an approach to embedded software design based on executable models expressed in the high-level modelling paradigm of Timber. In this paper we extend previous work on Timber with a multi-paradigm design environment, aiming to bridge the gap between engineering disciplines by multi-body co-simulation of vehicle dynamics, embedded electronics, and embedded executable models. Its feasibility is demonstrated on a case study of a typical automotive application (traction control), and its potential advantages are discussed, as highlighted below:shorter time to market through concurrent, co-operative distributed engineering, andreduced cost through adequate system design and dimensioning, andimproved efficiency of the design process through migration and reuse of executable software components, andreduced need for hardware testing, by specification verification on the executable model early in the design process, andimproved quality, by opening up for formal methods for verification.

  • 9.
    Hu, Xianfeng
    et al.
    Process Metallurgy Department, Swerea MEFOS AB.
    Sundqvist-Öqvist, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi. Process Metallurgy Department, Swerea MEFOS AB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Yang, Qixing
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Björkman, Bo
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Direct alloying steel with chromium by briquettes made from chromite ore, mill scale, and petroleum coke2017Ingår i: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 88, nr 5, artikel-id 1600247Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, the effectiveness of using briquettes made from chromite ore, mill scale, and petroleum coke for direct chromium alloying is tested by induction furnace trials carried out in three different scales. The experimental results show that steel scrap can be alloyed with chromium by the chromite ore in the briquettes and the Cr yield from the chromite ore increases with the increase in mill scale addition to the briquettes: the more mill scale is added to the briquettes, the lower the mass ratio of Cr to (Cr+Fe) would be, leading to a higher Cr yield from the chromite ore. Specifically, the maximum Cr yield from the chromite ore is 99.9% when the mass ratio of Cr to (Cr+Fe) in the briquettes is 0.05, and being 93.0% when the ratio is 0.10. However, when the ratio of Cr to (Cr+Fe) in the briquettes reaches 0.20, the maximum Cr yield is only 67.1%. The reduction of chromite ore under the present experimental conditions is promoted by a solid-state reduction mechanism

  • 10.
    Leijon, Viktor
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    FIFO WiDOM: timely control over wireless links2007Ingår i: Proceedings of the 2007 IEEE Conference on Control Applications: Singapore, 1 - 3 October 2007 ; [part of IEEE Multi-Conference on Systems and Control, MSC], Piscataway, NJ: IEEE Communications Society, 2007, s. 1024-1030Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present the idea of scheduling a control network in a first-come first-serve manner, and demonstrate a way to implement this over a wireless link. This achieves real-time guarantees and tightly bounded jitter for control applications. Further, how to design systems using this network is discussed, and the benefits compared to a standard priority MAC protocol are examined through simulations and a prototype implementation. The prototype is implemented using the reactive Timber programming model on a lightweight 8-bit platform.

  • 11.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    IP over CAN: transparent vehicular to infrastructure access2008Ingår i: 2008 Consumer Communications and Networking Conference: [IEEE CCNC 2008] ; Las Vegas, Nevada, 10 - 12 January 2008, Piscataway, NJ: IEEE Communications Society, 2008, s. 758-759Konferensbidrag (Refereegranskat)
    Abstract [en]

    For the future we foresee each vehicle to feature wireless communication (to the Internet and/or other vehicles) over various technologies, e.g., UMTS/GPRS, and WLAN/WiFi. In this paper we show how access to such communication resources could be granted to individual components (CAN bus connected ECUs) in the car by allowing transparent data transport using the standardized Internet Protocol (IP). Our experiments show that a complete IP Over CAN implementation, providing both UDP and TCP transport over IP, running on an Atmel AT90CAN128 is capable of transfer speeds up to 200 kbits while using less than 2 kbytes of dynamic RAM.

  • 12.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pietrzak, Pawel
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Wiklander, Jimmie
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Scheduling of CRO systems under SPR-DM2011Konferensbidrag (Refereegranskat)
  • 13.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    Response Time for IEC 61499 over Ethernet2015Ingår i: IEEE International Conference on Industrial Informatics: INDIN 2015, Cambridge, UK, July 22-24, 2015. Proceedings, Piscataway, NJ: IEEE Communications Society, 2015, s. 1206-1212, artikel-id 7281907Konferensbidrag (Refereegranskat)
    Abstract [en]

    The IEC 61499 standard provides means to specify distributed control systems in terms of function blocks. For the deployment, each device may hold one or many logical resources, each consisting of a function block network with service interface blocks at the edges. The execution model is event driven (asynchronous), where triggering events may be associated with data (and seen as a message). In this paper we propose a low complexity implementation technique allowing to asses end-to-end response time of event chains spanning a networked devices. Based on a translation of IEC 61499 to RTFM-tasks and resources, the response time for each task in the system can be derived using established scheduling techniques. In this paper we develop a method to provide safe end-to-end response time taking both intra- and inter-device delivery delays into account. As a use case we study the implementation onto (single-core) ARMcortex based devices communicating over a switched Ethernet network. For the analysis we define a generic switch model, and an experimental setup allowing us to study the impact of network topology as well as 802.1Q quality of service in a mixed critical setting. Our results indicate that safe sub milli-second end-to-end response times can be obtained using the proposed approach.

  • 14.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pereira, David
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    End-to-End Response Time of 61499 Distributed Applications over Switched Ethernet2017Ingår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 13, nr 1, s. 287-297Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The IEC 61499 standard provides means to specify distributed control systems in terms of function blocks. For the deployment, each device may hold one or many logical resources, each consisting of a function block network with service interface blocks at the edges. The execution model is event driven (asynchronous), where triggering events may be associated with data (and seen as messages). In this paper, we propose a low complexity implementation technique allowing to assess end-to-end response times of event chains spanning over a set of networked devices. Based on a translation of IEC 61499 to RTFM1-tasks and resources, the response time for each task in the system at device-level can be derived using established scheduling techniques. In this paper, we develop a holistic method to provide safe end-to-end response times taking both intra- and inter-device delivery delays into account. The novelty of our approach is the accuracy of the system scheduling overhead characterization. While the device-level (RTFM) scheduling overhead was discussed in previous works, the network-level scheduling overhead for switched Ethernets is discussed in this paper. The approach is generally applicable to a wide range of COTS Ethernet switches without a need for expensive custom solutions to provide hard real-time performance. A behavior characterization of the utilized switch determines the guaranteed response times. As a use case, we study the implementation onto (single-core) ARMcortex based devices communicating over a switched Ethernet network. For the analysis, we define a generic switch model and an experimental setup allowing us to study the impact of network topology as well as 802.1Q quality of service in a mixed critical setting. Our results indicate that safe sub millisecond end-to-end response times can be obtained using the proposed approach.

  • 15.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pereira, David J.
    ISEP, Instituto Superior de Engenharia do Porto.
    Pinho, Luis Miguel
    ISEP, Instituto Superior de Engenharia do Porto.
    RTFM-lang static semantics for systems with mixed criticality2014Ingår i: Ada User Journal, ISSN 1381-6551, Vol. 35, nr 2, s. 128-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In an embedded system, functions often operate under different requirements. In the extreme, a failing safety critical function may cause collateral damage (and hence consider to be a system failure) while non critical functions affect only the quality of service. Approaches by partitioning the system's functions into sandboxes require virtualization mechanisms by the underlying platform and thus prohibit deployment to the bulk of microcontroller based systems. In this paper we discuss an alternative approach based on static semantic analysis performed directly on the system specification expressed in the form of an object oriented (00) model in the experimental language RTFM-lang. This would allow to (at compile time) to discriminate in between critical and non-critical functions, and assign these (by means of statically checkable typing rules) appropriate access rights. In particular, one can imagine dynamic memory allocations to be allowed only in non-critical functions, while on the other hand, direct interaction with the environment may be restricted to the critical parts. With respect to scheduling, a static task and resource configuration allows e.g. Stack Resource Policy (SRP) based approaches to be deployed. In this paper we discuss how this can be achieved in a mixed critical setting.

  • 16.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Vyatkin, Valeriy
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Real-Time Execution of Function Blocks for Internet of Things using the RTFM-kernel2014Ingår i: Proceedings of 2014 IEEE 19th International Conference on Emerging Technologies & Factory Automation (ETFA 2014): Barcelona, Spain, 16-19 Sept. 2014, Piscataway, NJ: IEEE Communications Society, 2014, s. 1-6, artikel-id 7005232Konferensbidrag (Refereegranskat)
    Abstract [en]

    Function Blocks provides a means to model andprogram industrial control systems. The recently acclaimed IEC61499 standard allows such system models to be partitioned andexecuted in a distributed fashion. At device level, such models aretraditionally implemented onto programmable logic controllersthat underneath have an operating system and a softwarerun-time environment which implies high resource demands.However, there is a current trend to involve small embeddedsystems (so called Internet of Things devices) integrated into suchdistributed control systems. To this end, we seek to address theoutsets for real-time execution of Function Block based designsonto light-weight controllers (MCUs) with limited resources(memory and CPU). Furthermore, we propose a mapping ofthe Function Block execution semantics onto the RTFM-kernel,and discuss opportunities for off-line (design time) analysis withrespect to response time, overall schedulability and memoryrequirements.

  • 17.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindner, Andreas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Vyatkin, Valeriy
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    RTFM-4-FUN2014Ingår i: 2014 9th IEEE International Symposium on Industrial Embedded Systems (SIES 2014): Pisa, 18-20 June 2014, Piscataway, NJ: IEEE Communications Society, 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Function Blocks provides a means to model andprogram industrial control systems. The recently acclaimed IEC61499 standard allows such system models to be partitioned andexecuted in a distributed fashion. At device level, such models aretraditionally implemented onto programmable logic controllersand industrial PCs. In this paper, we discuss work in progresson developing a mapping allowing to implement a subset of IEC61499 models onto light-weight embedded devices (MCUs). Wepropose and detail an event semantics, and its mapping to thenotions of tasks and resources for Stack Resource Policy basedanalysis and scheduling. Moreover, we show how the proposedmapping can be efficiently implemented under the RTFM-kernel.Finally we outline a prototype tool-chain and discuss related,ongoing and future work.

  • 18.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Mäkitaavola, Henrik
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eliasson, Jens
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Leveraging tinyos for integration in process automation and control systems2012Ingår i: IECON 2012: 38th Annual Conference of the IEEE Industrial Electronics Society, Piscataway, NJ: IEEE Communications Society, 2012, s. 5779-5785Konferensbidrag (Refereegranskat)
    Abstract [en]

    The number and complexity of networked sensors and actuators in industrial monitoring and control systems is rapidly increasing. This calls for flexible yet efficient methods (w.r.t. time and money) for designing, deploying and maintaining such systems. To this end, Service Oriented Architectures (SOAs) and wireless technologies are foreseen to play important roles. In the area of Wireless Sensor Networks (WSNs), TinyOS (TOS) has gained wide spread use, mainly because it offers a simple programming model. Moreover TOS comes with a ready made code base (e.g., protocol stacks needed to implement SOA enabled devices) and is available for a large number of light-weight target platforms. However, TOS has yet to make its way into industrial applications where real-time operation is required (which is typical to monitoring and control systems). As being designed primarily with simplicity in mind, the TOS execution model for tasks is non-preemptive, limiting system responsiveness and schedulability. To overcome this problem preemptive TOSThreads has been introduced. However, this introduces the additional complexity of traditional multi-thread programming, thus the main benefit of TOS is lost. In this paper we present an alternative execution model for TOS, that allows preemptive execution while preserving the simplicity of vintage TOS. We exemplify the impact of scheduling to a typical sensor/actuator node scenario. Our results indicate that the proposed preemptive execution model is capable of reducing both delay and drop rate for the given scenario.

  • 19.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nordlander, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    TinyTimber, reactive objects in C for real-time embedded systems2008Ingår i: Proceedings, Design, Automation and Test in Europe: DATE '08 ; Munich, Germany, 10 - 14 March 2008 / [ed] Donatella Sciuto, New York: ACM Digital Library, 2008, s. 1382-1385Konferensbidrag (Refereegranskat)
    Abstract [en]

    Embedded systems are often operating under hard real-time constraints. Such systems are naturally described as time-bound reactions to external events, a point of view made manifest in the high-level programming and systems modeling language Timber. In this paper we demonstrate how the Timber semantics for parallel reactive objects translates to embedded real-time programming in C. This is accomplished through the use of a minimalistic Timber Run-Time system, TinyTimber (TT). The TT kernel ensures state integrity, and performs scheduling of events based on given time-bounds in compliance with the Timber semantics. In this way, we avoid the volatile task of explicitly coding parallelism in terms of processes/threads/semaphores/monitors, and side-step the delicate task to encode time-bounds into priorities. In this paper, the TT kernel design is presented and performance metrics are presented for a number of representative embedded platforms, ranging from small 8-bit to more potent 32-bit micro controllers. The resulting system runs on bare metal, completely free of references to external code (even C-lib) which provides a solid basis for further analysis. In comparison to a traditional thread based real-time operating system for embedded applications (FreeRTOS), TT has tighter timing performance and considerably lower code complexity. In conclusion, TinyTimber is a viable alternative for implementing embedded real-time applications in C today.

  • 20.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nordlander, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Hyyppä, Kalevi
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Aittamaa, Simon
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Comprehensive reactive real-time programming2008Ingår i: Hawaii International Conference on Education: 2008 Conference Proceedings, 2008, s. 1440-1448Konferensbidrag (Refereegranskat)
  • 21.
    Lindgren, Per
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Nordlander, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Kero, Martin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Robust real-time applications in Timber2006Ingår i: 2006 IEEE International Conference on Electro/information Technology: East Lansing. MI, 7 - 10 May 2006, Piscataway, NJ: IEEE Communications Society, 2006, s. 191-196Konferensbidrag (Refereegranskat)
    Abstract [en]

    Embedded systems are often operating under hard real-time constraints, for example in automotive applications. For such systems, robustness and reliability are crucial, which calls for rigorous system design and methodologies for validation. In this paper we advocate a design methodology for robust, realtime systems, based on Timber; a pure reactive system model that allows for formal reasoning about various system properties. We outline how system specifications in Timber can be "compiled" into efficient standalone executables for general light-weight microcontroller platforms. Methods for resource analysis and implications to system dimensioning and validation are further discussed.

  • 22. Nybacka, Mikael
    et al.
    Larsson, Tobias
    Jeppsson, Peter
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Produkt- och produktionsutveckling.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karlsson, Lennart
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Andren, Henrik
    Engström, Niclas
    Larsson, Roland
    Fransson, Lennart
    Hyyppä, Kalevi
    Fredriksson, Håkan
    Eriksson, Johan
    van Deventer, Jan
    Tingvall, Bror
    Project: CASTT - Centre for Automotive Systems Technologies and Testing2007Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Through the Centre for Automotive Systems Technologies and Testing, Luleå University of Technology aims to first of all support automotive winter testing in Northern Sweden. This means to support the local automotive test entrepreneurs and through them their customers: the car manufacturers and their suppliers. To succeed in this task, the center relies on the university's areas of leading research and most importantly on the cooperation between those areas.

  • 23.
    Wiklander, Jimmie
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    An IDE for component-based design of embedded real-time software2011Ingår i: 6th IEEE International Symposium on Industrial Embedded Systems (SIES), Piscataway, NJ: IEEE Communications Society, 2011, s. 47-50Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper describes work in progress on a tool for component-based design of embedded real-time software. The tool supports graphical modeling of software systems using concurrent reactive objects and components, as well as generation of C code from the model. The resulting application code can then be combined with a lightweight kernel for execution on bare metal.

  • 24.
    Wiklander, Jimmie
    et al.
    Luleå tekniska univesitet.
    Eriksson, Johan
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Lindgren, Per
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Utilizing an IDE for component-based design of embedded real-time software for an autonomous car2011Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Embedded systems are inherently reactive and they often operate under resource and real-time constraints. Hence, a model supporting these fundamental properties is desirable for an efficient and correct design process. To this end, we have developed a component model and design methodology that enables component-based design of embedded software. Moreover, we have developed an Integrated Development Environment (IDE) that ensures a systematic development of software in accordance with the methodology.

    In this paper we review the IDE and it’s underlying modeling framework and demonstrate its applicability through a use-case with typical properties - a control system with real-time constraints and hardware interaction. This paper describes the whole design process – requirements specification, conceptual model, component-level design, component implementation, code synthesis, testing, and verification. In particular, we show how the modeling framework enforces a static component and communication structure reflecting the concurrent behavior of the system and its interaction with the environment (target platform).

    Our results (a working protoype) indicate applicability of the presented design approach, and show the IDE’s ability to generate efficient executables. Additionally, we show how to prove the schedulability of the target system in the IDE using standard scheduling theorems and machine assisted WCET measurements.

    In conclusion, this paper demonstrates both the applicability of the software design methodology and the functionality of the developed IDE.

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