Fundamentals of Implementing Real-Time Control Applications in Distributed Computer Systems

Törngren, Martin

doi:10.1007/978-0-585-35223-7_2

Cited by 52 publications

(60 citation statements)

References 26 publications

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“…In this configuration, the k-th information can be lost when the k+1-th information is used in the real-time processor before the kth information [19][20][21], because some jitter of each event and duration is unavoidable.…”

Section: Asynchronous Configurationmentioning

confidence: 99%

Design and Temporal Analysis of Hardware-in-the-loop Simulation for Testing Motor Control Unit

Choi¹,

Lee²,

Lee³

2012

Journal of Electrical Engineering and Technology

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-This paper describes a design and temporal analysis of a hardware-in-the-loop (HIL) simulation environment for testing a motor control unit (MCU). The design concepts and main characteristics including unavoidable time delays of each component module are described. From temporal analysis results according to the module integration method, an appropriate solution is proposed to fix and minimize time delays. In order to verify the effectiveness of the proposed solution, the HIL test results are compared with the results of experiments and an offline simulation.

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Section: Asynchronous Configurationmentioning

confidence: 99%

Design and Temporal Analysis of Hardware-in-the-loop Simulation for Testing Motor Control Unit

Choi¹,

Lee²,

Lee³

2012

Journal of Electrical Engineering and Technology

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“…Therefore, they typically try to model the physical system as accurately as possible, integrating the properties of the sensors and actuators as well as their interdependencies in a global system model. In doing so, traditional control theory, which still is the predominant paradigm for many controllers, assumes that all inputs are sampled instantaneously and equidistantly, providing a temporally consistent snapshot of the physical environment [1]. The resulting process control system (PCS), which consists of digital signal processing (DSP) and control, is therefore monolithic and structured in a relatively simple manner -sample, compute, and act.…”

Section: Introductionmentioning

confidence: 99%

Taking control: Modular and adaptive robotics process control systems

Ulbrich

Franzmann

Harkort

et al. 2012

2012 IEEE International Symposium on Robotic and Sensors Environments Proceedings

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Abstract-Robotics systems usually comprise sophisticated sensor and actuator systems with no less complex control applications. These systems are subject to frequent modifications and extensions and have to adapt to their environment. While automation systems are tailored to particular production processes, autonomous vehicles must adaptively switch their sensors and controllers depending on environmental conditions. However, when designing and implementing the process control system, traditional control theory focuses on the control problem at hand without having this variability in mind. Thus, the resulting models and implementation artefacts are monolithic, additionally complicating the real-time system design.In this paper, we present a modularisation approach for the design of robotics process control systems, which not only aims for variability at design-time but also for adaptivity at run-time. Our approach is based on a layered control architecture, which includes an explicit interface between the two domains involved: control engineering and computer science. Our architecture provides separation of concerns in terms of independent building blocks and data flows. For example, the replacement of a sensor no longer involves the tedious modification of downstream filters and controllers. Likewise, the error-prone mapping of high-level application behaviour to the process control system can be omitted. We validated our approach by the example of an autonomous vehicle use case. Our experimental results demonstrate ease of use and the capability to maintain quality of control on par with the original monolithic design.

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“…Although applications employing digital controllers are structured in a relatively simple manner -sample, compute, and acttheir implementation is anything but easy. Traditional control theory, which still is the predominant paradigm for many controllers, assumes that all inputs are sampled instantaneously and equidistantly, providing a temporally consistent snapshot of the physical environment [1]. It is, however, almost impossible to actually meet this requirement in practical implementations of digital control loops.…”

Section: Introductionmentioning

confidence: 99%

Design by uncertainty: Towards the use of measurement uncertainty in real-time systems

Ulbrich

Franzmann

Scheler

et al. 2012

7th IEEE International Symposium on Industrial Embedded Systems (SIES'12)

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Abstract-Real-time systems usually incorporate a wide variety of challenges: A control engineer, for example, aims for the highest possible control quality achievable. Here, one key element is to minimise the uncertainty of the measurements. This, to put it simple, is the noise of sensor data, which has a negative effect on control. Although measurement uncertainty is well treated in control theory, it is usually ignored in common real-time architectures where temporal properties are the prevalent criteria. Consequently, the communication between control engineers and real-time specialists is rather one way, revolving around deadlines and sampling periods. However, on closer examination, many real-time properties are derived from the measurement uncertainty aspired by the control engineer. Conversely, temporal variations, virtually inevitable in practice, can be represented as measurement uncertainty as well.Tackling the measurement uncertainty should therefore be an interdisciplinary task: The control system respects the actual run-time conditions instead of estimating them. Likewise, the real-time system considers measurement uncertainty rather than blindly sticking to deadlines. In this paper we present an uncertainty-centric approach to leverage measurement uncertainty in real-time architectures, not only at design time but also at run-time. Using measurement uncertainty as an explicit interface minimises the gap between real-time specialists and control engineers and facilitates a modular and flexible system design. Our preliminary results are promising and show the ease of use and the applicability to existing systems.

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Fundamentals of Implementing Real-Time Control Applications in Distributed Computer Systems

Cited by 52 publications

References 26 publications

Design and Temporal Analysis of Hardware-in-the-loop Simulation for Testing Motor Control Unit

Design and Temporal Analysis of Hardware-in-the-loop Simulation for Testing Motor Control Unit

Taking control: Modular and adaptive robotics process control systems

Design by uncertainty: Towards the use of measurement uncertainty in real-time systems

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