| 1. |
- Adaldo, Antonio, 1989-, et al.
(författare)
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Event-triggered pinning control of complex networks with switching topologies
- 2014
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Ingår i: Proceedings of the 53rd annual IEEE Conference on Decision and Control. - 9781479977468 ; , s. 2783-2788
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the problem of eventtriggered pinning control for the synchronization of networks of nonlinear dynamical agents onto a desired reference trajectory. The pinned agents are those that have access to the reference trajectory. We consider both static and switching topologies. We prove that the system is well posed and identify conditions under which the network achieves exponential convergence. A lower bound for the rate of convergence is also derived. Numerical examples demonstrating the effectiveness of the results are provided.
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| 2. |
- Andreasson, Martin, 1987-, et al.
(författare)
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Control of MTDC Transmission Systems under Local Information
- 2014
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Ingår i: Decision and Control (CDC), 2014 IEEE 53rd Annual Conference on. - : IEEE conference proceedings. - 9781479977468 ; , s. 1335-1340
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Konferensbidrag (refereegranskat)abstract
- High-voltage direct current (HVDC) is a commonly used technology for long-distance electric power transmission, mainly due to its low resistive losses. In this paper a distributed controller for multi-terminal high-voltage direct current (MTDC) transmission systems is considered. Sufficient conditions for when the proposed controller renders the closed-loop system asymptotically stable are provided. Provided that the closed loop system is asymptotically stable, it is shown that in steady-state a weighted average of the deviations from the nominal voltages is zero. Furthermore, a quadratic cost of the current injections is minimized asymptotically.
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| 3. |
- Araújo, José, et al.
(författare)
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A down-sampled controller to reduce network usage with guaranteed closed-loop performance
- 2014
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Ingår i: Decision and Control (CDC), 2014 IEEE 53rd Annual Conference on. - : IEEE conference proceedings. - 9781479977468 ; , s. 6849-6856
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Konferensbidrag (refereegranskat)abstract
- We propose and evaluate a down-sampled controller which reduces the network usage while providing a guaranteed desired linear quadratic control performance. This method is based on fast and slow sampling intervals, as the closed-system benefits by being brought quickly to steady-state conditions while behaving satisfactorily when being actuated at a slow rate once at those conditions. This mechanism is shown to provide large savings with respect to network usage when compared to traditional periodic time-triggered control and other aperiodic controllers proposed in the literature.
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| 4. |
- Dürango, Jonas, et al.
(författare)
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Control-theoretical load-balancing for cloud applications with brownout
- 2014
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Ingår i: 2014 IEEE 53RD ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC). - 9781467360906 - 9781479977468 ; , s. 5320-5327
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Konferensbidrag (refereegranskat)abstract
- Cloud applications are often subject to unexpected events like flash crowds and hardware failures. Without a predictable behaviour, users may abandon an unresponsive application. This problem has been partially solved on two separate fronts: first, by adding a self-adaptive feature called brownout inside cloud applications to bound response times by modulating user experience, and, second, by introducing replicas - copies of the applications having the same functionalities - for redundancy and adding a load-balancer to direct incoming traffic. However, existing load-balancing strategies interfere with brownout self-adaptivity. Load-balancers are often based on response times, that are already controlled by the self-adaptive features of the application, hence they are not a good indicator of how well a replica is performing. In this paper, we present novel load-balancing strategies, specifically designed to support brownout applications. They base their decision not on response time, but on user experience degradation. We implemented our strategies in a self-adaptive application simulator, together with some state-of-the-art solutions. Results obtained in multiple scenarios show that the proposed strategies bring significant improvements when compared to the state-of-the-art ones.
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| 5. |
- Feyzmahdavian, Hamid Reza, et al.
(författare)
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On the Convergence Rates of Asynchronous Iterations
- 2014
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Ingår i: Decision and Control (CDC), 2014 IEEE 53rd Annual Conference on. - : IEEE conference proceedings. - 9781479977468 ; , s. 153-159
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Konferensbidrag (refereegranskat)abstract
- This paper presents a unifying convergence result for asynchronous iterations involving pseudo-contractions in the block-maximum norm. Contrary to previous results which only established asymptotic convergence or studied simplified models of asynchronism, our result allows to bound the convergence rates for both partially and totally asynchronous implementations. Several examples are worked out to demonstrate that our theorem recovers and improves on existing results, and that it allows to characterize the solution times for several classes of asynchronous iterations that have not been addressed before.
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| 6. |
- Fresk, Emil, et al.
(författare)
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Frame Induced Vibration Estimation and Attenuation Scheme on a Multirotor helicopter
- 2015
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Ingår i: Decision and Control (CDC). - Piscataway, NJ : IEEE Communications Society. - 9781479977468 ; , s. 5698-5703
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Konferensbidrag (refereegranskat)abstract
- The aim of this article is to establish an induced frame vibration and attenuation scheme, specifically targeting the area of multi-rotor Unmanned Aerial Vehicles (UAVs), such as quadrotors. These types of unmanned small scale helicopters are characterised by small and light frames, which are vulnerable to vibrations induced by the operation of the motors or external environmental factors. The existence of such vibrations effecting the frame can significantly deteriorate the performance of the overall closed system and even drive it to instabilities. In this article spectral estimation schemes based on: a) Autoregressive (AR) modelling and b) Multiple Signal Classification (MUSIC) are being established and evaluated towards their ability to detect the induced vibration frequencies on the UAV, while an extended discussion is being presented on selecting the correct number of the identified induced vibrating frequencies. In a sequential stage, a vibration attenuation approach based on notch filtering is being presented, being able to correctly attenuate the induced vibrating frequencies in the measurements. The efficiency of the overall suggested scheme is being evaluated by experimental results that indicate the significant improvement in the measurements achieved bythe direct application of the proposed scheme.
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| 7. |
- Linder, Jonas, 1984-, et al.
(författare)
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A Closed-loop Instrumental Variable Approach to Mass and Center of Mass Estimation Using IMU Data
- 2014
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Ingår i: Proceedings of the 53rd Conference on Decision and Control. - 9781479977468 ; , s. 283-289
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Konferensbidrag (refereegranskat)abstract
- In this paper, an instrumental variable (IV) method for estimating the mass and center of mass (CM) of a ship using IMU data has been further investigated. Here, this IV method, which was proposed in an earlier paper, has been analyzed from a closed-loop point of view. This new perspective reveals the properties of the system and dependencies of the signals used in the estimation procedure. Due to similarities with closed-loop identification, previous results in the closed-loop identification field have been used as an inspiration to improve the IV estimator. Since the roll dynamics of a ship is well described by a pendulum model, a pendulum experiment has been carried out to validate the performance both of the original and the improved IV estimators. The experiments gave good results for the improved IV estimator with significantly lower variances and relative errors than the previous IV estimator.
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| 8. |
- Nilsson, Gustav, et al.
(författare)
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On Resilience of Multicommodity Dynamical Flow Networks
- 2014
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Ingår i: 53rd IEEE Conference on Decision and Control. - 9781479977468 ; , s. 5125-5130
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Konferensbidrag (refereegranskat)abstract
- Dynamical flow networks with heterogeneous routing are analyzed in terms of stability and resilience to perturbations. Particles flow through the network and, at each junction, decide which downstream link to take on the basis of the local state of the network. Differently from single-commodity scenarios, particles belong to different classes, or commodities, with different origins and destinations, each reacting differently to the observed state of the network. As such, the commodities compete for the shared resource that is the flow capacity of each link of the network. This implies that, in contrast to the single-commodity case, the resulting dynamical system is not monotone, hence harder to analyze. It is shown that, in an acyclic network, when a feasible globally asymptotically stable aggregate equilibrium exists, then each commodity also admits a unique equilibrium. In addition, a sufficient condition for stability is provided. Finally, it is shown that, differently from the single-commodity case, when this condition is not satisfied, the possible unique equilibrium may be arbitrarily fragile to perturbations of the network.
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| 9. |
- Parisio, Alessandra, et al.
(författare)
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Control of HVAC Systems via Scenario-based Explicit MPC
- 2015
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Ingår i: 2014 IEEE 53rd Annual Conference on Decision and Control : (CDC 2014). - Piscataway, NJ : IEEE Communications Society. ; , s. 5201-5207, s. 5201-5207
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Konferensbidrag (refereegranskat)abstract
- Improving energy efficiency of Heating, Ventilation and Air Conditioning (HVAC) systems is a primary objective for the society. Model Predictive Control (MPC) techniques for HVAC systems have recently received particular attention, since they can naturally account for several factors, such as weather and occupancy forecasts, comfort ranges and actuation constraints. Developing effective MPC based control strategies for HVAC systems is nontrivial, since buildings dynamics are nonlinear and affected by various uncertainties. Further, the complexity of the MPC problem and the burden of on-line computations can lead to difficulties in integrating this scheme into a building management system.We propose to address this computational issue by designing a scenario-based explicit MPC strategy, i.e., a controller that is simultaneously based on explicit representations of the MPC feedback law and accounts for uncertainties in the occupancy patterns and weather conditions by using the scenarios paradigm. The main advantages of this approach are the absence of a-priori assumptions on the distributions of the uncertain variables, the applicability to any type of building, and the limited on-line computational burden, enabling practical implementations on low-cost hardware platforms.We illustrate the practical implementation of the proposed explicit MPC controller on a room of a university building, showing its effectiveness and computational tractability.
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| 10. |
- Sadeghi, Maryam, et al.
(författare)
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IMU-based vehicle load estimation under normal driving conditions
- 2014
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Ingår i: Proceedings of the 53rd IEEE Conference on Decision and Control. - 9781479977468 ; , s. 3376-3381
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Konferensbidrag (refereegranskat)abstract
- In vehicle load detection and estimation, having an accurate estimate of the height of the Center of Gravity (CG) and the Roll Center (RC) is crucial. In this paper, taking advantage of the availability of Inertial Measurement Units (IMUs) in automotive vehicles, the nominal CG and RC heights are estimated and used for the main purpose of roof load detection. RC estimation is formulated as an Errors-in-Variables regression model. The Total and Corrected Least Squares (TLS and CLS) approaches are applied and a comparison is performed. Using the knowledge of the covariance matrix, CLS provides consistent estimates of the RC height. The estimated RC and CG heights are used to estimate the roof load using a greybox model and the method is applied to measurements from normal driving conditions.
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