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Proceedings ArticleDOI

On the performance of the PIDPLUS controller in wireless control systems

23 Jun 2010-pp 707-714
TL;DR: The results suggest that PIDPLUS can well be used for wireless control, but better performance could be attained by further development of the controller tuning methodology.
Abstract: The PIDPLUS algorithm is one of the candidates to be used in wireless automation systems. The control performance of this algorithm under packet losses is investigated in the paper. First, the performance of PIDPLUS is evaluated with respect to packet loss rates for a general first-order plus time-delay process, a model widely used for controller tuning. This simulation study reveals how the performance is affected by packet losses in a wireless control system. Secondly, we will elaborate on the implementation of PIDPLUS and discuss its design, tuning and performance in wireless control systems in light of an unstable case process. The results suggest that PIDPLUS can well be used for wireless control, but better performance could be attained by further development of the controller tuning methodology.
Citations
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Journal ArticleDOI
TL;DR: The proposed tuning methodology is independent of the specific choice of plant and is also applicable for less complicated systems, thus it is useful in a wide variety of scenarios.
Abstract: The issues of stochastically varying network delays and packet dropouts in Networked Control System (NCS) applications have been simultaneously addressed by time domain optimal tuning of fractional order (FO) PID controllers. Different variants of evolutionary algorithms are used for the tuning process and their performances are compared. Also the effectiveness of the fractional order PI λ D μ controllers over their integer order counterparts is looked into. Two standard test bench plants with time delay and unstable poles which are encountered in process control applications are tuned with the proposed method to establish the validity of the tuning methodology. The proposed tuning methodology is independent of the specific choice of plant and is also applicable for less complicated systems. Thus it is useful in a wide variety of scenarios. The paper also shows the superiority of FOPID controllers over their conventional PID counterparts for NCS applications.

57 citations

Journal ArticleDOI
TL;DR: In this article, an event-based proportional-integral (PI) control scheme for stable first-order processes is considered, where a triggering mechanism which decides the transmission instants based on an estimate of the PI control signal is proposed, which addresses some side effects that have been discovered in previous event-triggered PI proposals, which trigger on the process output.

37 citations


Cites methods from "On the performance of the PIDPLUS c..."

  • ...Additionally, when the networ k is wireless, the control system designer should take into acco unt bandwidth usage and energy consumption in the control loop design, Willig [2008]. Hence, new controller structures an d PI tunings methods are required. To cope with these problems, event-based techniques for control were recently introduced,̊ Aström and Bernhardsson [1999], Tabuada [2007]. Such techniques allow an efficient u tilization of the network resources, while ensuring a desired b havior of the closed-loop system....

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  • ...Although PIDPLUS was introduced to deal wit h packet losses and time delays, and its stability properties and performances are tested mainly by simulation or with experi mental test-beds, Ungan [2010], Kaltiokallio et al. [2010] , here we adopt such a controller in an event-based fashion, furthe r providing stability conditions in a rigorous way....

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  • ...Additionally, when the networ k is wireless, the control system designer should take into acco unt bandwidth usage and energy consumption in the control loop design, Willig [2008]. Hence, new controller structures an d PI tunings methods are required....

    [...]

  • ...Additionally, when the networ k is wireless, the control system designer should take into acco unt bandwidth usage and energy consumption in the control loop design, Willig [2008]. Hence, new controller structures an d PI tunings methods are required. To cope with these problems, event-based techniques for control were recently introduced,̊ Aström and Bernhardsson [1999], Tabuada [2007]. Such techniques allow an efficient u tilization of the network resources, while ensuring a desired b havior of the closed-loop system. This is achieved by exchan ging information between sensor, controllers and actuators only when relevant information is available. The use of these tec hniques has attracted much attention from the area NCSs, Wang and Lemmon [2011], and applied for PI or PID control Vasyutynskyy and Kabitzsch [2007], Rabi and Johansson [2008], Durand and Marchand [2009], Sánchez et al....

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  • ...Additionally, when the networ k is wireless, the control system designer should take into acco unt bandwidth usage and energy consumption in the control loop design, Willig [2008]. Hence, new controller structures an d PI tunings methods are required. To cope with these problems, event-based techniques for control were recently introduced,̊ Aström and Bernhardsson [1999], Tabuada [2007]....

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Journal ArticleDOI
TL;DR: Simulation and experimental results obtained with a laboratory setup demonstrate the effectiveness of the methodology in providing a satisfactory performance related to set-point and load disturbance step responses with a total variation that is significantly reduced with respect to the standard cases.
Abstract: In this paper we propose a new event generator, which has strong noise-filtering capabilities, to be used in event-based control systems with a PIDPlus controller. An approximate frequency analysis is performed in order to characterize the event generator system and tuning guidelines are provided for its design parameter. Simulation and experimental results obtained with a laboratory setup demonstrate the effectiveness of the methodology in providing a satisfactory performance related to set-point and load disturbance step responses with a total variation that is significantly reduced with respect to the standard cases.

13 citations

Proceedings ArticleDOI
24 Aug 2015
TL;DR: This paper lays the foundation for control using a wireless actuator and demonstrates how traditional control methodologies can be modified to effectively work with general wireless communication.
Abstract: Wireless technologies have been successfully applied in the process industry since the creation of the first international standard IEC62591 WirelessHART. Applications started in areas where wireless sensors provide rich process information to the automation systems. Although real and demonstrated control applications are advertised, wireless-for-control is still in the initial stage and faces a lot of challenges. In particular, feedback latency and battery longevity, which are also problems for wireless-for-sensing, are even more critical when wireless actuators are applied. There are additional challenges in using wireless actuators because they actively affect the process. This paper lays the foundation for control using a wireless actuator. It demonstrates how traditional control methodologies can be modified to effectively work with general wireless communication. The innovations are tested with simulations and experimentations, both on commercial distributed control systems.

13 citations

Journal ArticleDOI
TL;DR: This paper is an extended version of the previous work documenting the internal logic of an implemented and working 6LoWPAN stack, Nanostack, and presents first the main architecture of the stack and subsequently describe the path followed by a packet transiting the different layers.
Abstract: There exist several open source 6LoWPAN stacks for researchers to experiment with. However, they often lack sufficient and in-depth description of the internal operation, which makes extending the stacks difficult for many of us. This paper is an extended version of our previous work documenting the internal logic of an implemented and working 6LoWPAN stack, Nanostack (v1.1). We present first the main architecture of the stack and subsequently describe the path followed by a packet transiting the different layers. Then we provide details of each one of the layers in the stack, with exception of the ICMP layer. The main logic in the MAC layer is comprehensively explained, and an undocumented layer used in nodes working as Gateway, the NRP layer, is presented. In addition we provide a conceptual view of the layering of the stack relative to the hardware platform and enumerate the typical tasks running in a sensor node.

10 citations

References
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Journal ArticleDOI
TL;DR: Insight into the properties of PI and PID control and simple tuning rules that give robust performance for processes with essentially monotone step responses are found.

842 citations


"On the performance of the PIDPLUS c..." refers background or methods in this paper

  • ...For all the configurations, the PID controller parameters are calculated by the AMIGO method....

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  • ...is the measurement filter with a time-constant Tf [16]....

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  • ...It means that if AMIGO tuning method is used, we will have δmax ≈ 1.1L for the control system in concern....

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  • ...Hence if L = 1, as it was in the previous simulations, the tolerable outage length in such a control system could be 1.1 s with the AMIGO tuned controller, and still the stability would be guaranteed....

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  • ...It has been shown in [19] that if the controller (2)-(3) with a second order filter (n = 2) is used for controlling the firstorder system (11) and the controller is tuned according to the AMIGO [16] method, the obtained jitter margin (9) becomes roughly δmax ≈ 0.7L....

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Journal ArticleDOI
TL;DR: This paper discusses a selection of promising and interesting research areas in the design of protocols and systems for wireless industrial communications that have either emerged as hot topics in the industrial communications community in the last few years, or which could be worthwhile research Topics in the next few years.
Abstract: In this paper we discuss a selection of promising and interesting research areas in the design of protocols and systems for wireless industrial communications. We have selected topics that have either emerged as hot topics in the industrial communications community in the last few years (like wireless sensor networks), or which could be worthwhile research topics in the next few years (for example cooperative diversity techniques for error control, cognitive radio/opportunistic spectrum access for mitigation of external interferences).

696 citations


"On the performance of the PIDPLUS c..." refers background in this paper

  • ...The randomness in delay times is caused by the MAC layer, microcontroller scheduling, low-quality clocks used in the hardware resulting in timing inaccuracies, multihop networking (routing), and the distributed and asynchronic nature of wireless control systems [4], [5], [6]....

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Journal ArticleDOI
31 May 2005
TL;DR: Key issues coming up in wireless fieldbus and wireless industrial communication systems are discussed: fundamental problems like achieving timely and reliable transmission despite channel errors; the usage of existing wireless technologies for this specific field of applications; and the creation of hybrid systems in which wireless stations are incorporated into existing wired systems.
Abstract: With the success of wireless technologies in consumer electronics, standard wireless technologies are envisioned for the deployment in industrial environments as well. Industrial applications involving mobile subsystems or just the desire to save cabling make wireless technologies attractive. Nevertheless, these applications often have stringent requirements on reliability and timing. In wired environments, timing and reliability are well catered for by fieldbus systems (which are a mature technology designed to enable communication between digital controllers and the sensors and actuators interfacing to a physical process). When wireless links are included, reliability and timing requirements are significantly more difficult to meet, due to the adverse properties of the radio channels. In this paper, we thus discuss some key issues coming up in wireless fieldbus and wireless industrial communication systems: 1) fundamental problems like achieving timely and reliable transmission despite channel errors; 2) the usage of existing wireless technologies for this specific field of applications; and 3) the creation of hybrid systems in which wireless stations are incorporated into existing wired systems.

693 citations


"On the performance of the PIDPLUS c..." refers background in this paper

  • ...Often the industrial applications pose stringent timing and reliability requirements [2], and with wireless solutions these are more difficult to meet than with wired due to the adverse properties of the radio channels [3]....

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Proceedings ArticleDOI
22 Apr 2008
TL;DR: An introduction to the architecture of WirelessHART is given and several challenges the implementation team had to tackle during the implementation are described, such as the design of the timer, network wide synchronization, communication security, reliable mesh networking, and the central network manager.
Abstract: Wireless technology has been regarded as a paradigm shifter in the process industry. The first open wireless communication standard specifically designed for process measurement and control applications, WirelessHART was officially released in September 2007 (as a part of the HART 7 Specification). WirelessHART is a secure and TDMA- based wireless mesh networking technology operating in the 2.4 GHz ISM radio band. In this paper, we give an introduction to the architecture of WirelessHART and share our first-hand experience in building a prototype for this specification. We describe several challenges we had to tackle during the implementation, such as the design of the timer, network wide synchronization, communication security, reliable mesh networking, and the central network manager. For each challenge, we provide a detailed analysis and propose our solution. Based on the prototype implementation, a simple WirelessHART network has been built for the purpose of demonstration. The demonstration network in turn validates our design. To the best of our knowledge, this is the first reported effort to build a WirelessHART protocol stack.

634 citations


"On the performance of the PIDPLUS c..." refers background in this paper

  • ...Often the industrial applications pose stringent timing and reliability requirements [2], and with wireless solutions these are more difficult to meet than with wired due to the adverse properties of the radio channels [3]....

    [...]

Journal ArticleDOI
TL;DR: Simple but powerful criteria of stability are presented for both continuous-time and discrete-time systems and using these criteria, stability can be checked in a closed loop Bode plot, making it easy to design the system for robustness.

334 citations


"On the performance of the PIDPLUS c..." refers background or methods in this paper

  • ...This stability criterion applies for a closed-loop system with process G, controller C and a variable timedelay Δ that represents the uncertain communication link (see [17] for details)....

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  • ...A relatively simple way to evaluate the stability and robustness of a WiNCS is the jitter margin [17]....

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