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- Solyom, Stefan, et al.
(författare)
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ABS control - A design model and control structure
- 2003
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Ingår i: Nonlinear and Hybrid Systems in Automotive Control. ; , s. 85-96
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The Anti-lock Braking System is an important component of acomplex steering system for the modern car. Most of ABS controllersavailable on the market are table and relay-feedback based.In the latest generation of “brake by wire” systems, the performancerequirements on the ABS are much higher. Control objective shiftsto maintain a specified tire slip during braking. The authors propose a design model and based on that a gain-scheduled controller that regulates the tire-slip. Simulation and test results are presented.
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| 5. |
- Agner, Felix, et al.
(författare)
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Anti-windup coordination strategy around a fair equilibrium in resource sharing networks
- 2023
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Ingår i: IEEE Control Systems Letters. - 2475-1456.
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Tidskriftsartikel (refereegranskat)abstract
- We coordinate interconnected agents where the control input of eachagent is limited by the control input of others. In that sense, the sys-tems have to share a limited resource over a network. Such problems canarise in different areas and it is here motivated by a district heating ex-ample. When the shared resource is insufficient for the combined needof all systems, the resource will have to be shared in an optimal fash-ion. In this scenario, we want the systems to automatically converge toan optimal equilibrium. The contribution of this paper is the proposalof a control architecture where each separate system is controlled by alocal PI controller. The controllers are then coordinated through a globalrank-one anti-windup signal. It is shown that the equilibrium of the pro-posed closed-loop system minimizes the infinity-norm of stationary statedeviations. A proof of linear-domain passivity is given, and a numericalexample highlights the benefits of the proposed method with respect tothe state-of-the-art.
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| 6. |
- Agner, Felix, et al.
(författare)
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Combating district heating bottlenecks using load control
- 2022
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Ingår i: Smart Energy. - : Elsevier BV. - 2666-9552. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The 4th generation of district heating systems face a potential problem where lowered water temperatures lead to higher flow rates, which requires higher hydraulic capacity in terms of pipe and pump sizes. This increases the effect of the already existing issue of hydraulic bottlenecks, causing peripheral units (customers) to experience reduced flow rates. A coordinating control strategy is presented in this work aimed at reducing the effect of such bottlenecks on the comfort of customers. This is done by distributing the flow deficit over many units rather than a few. Previous works mainly focus on MPC-structured controllers that depend on complex system models and online optimization techniques. This work proposes a method that requires little information about models for individual units and minimal IT communication between control systems. The proposed method is compared with a traditional control strategy and an optimal baseline in a simulation study. This shows that the proposed method can decrease the worst case indoor temperature deviations.
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| 7. |
- Agner, Felix, et al.
(författare)
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Decentralized PI-control and Anti-windup in Resource Sharing Networks
- 2024
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Ingår i: European Journal of Control. - 1435-5671.
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Tidskriftsartikel (refereegranskat)abstract
- We consider control of multiple stable first-order systems which have a control coupling described by an M-matrix. These agents are subject to incremental sector-bounded nonlinearities. We show that such plants can be globally asymptotically stabilized to a unique equilibrium using fully decentralized proportional integral anti-windup-equipped controllers subject to local tuning rules. In addition, we show that when the nonlinearities correspond to the saturation function, the closed-loop asymptotically minimizes a weighted 1-norm of the agents state mismatch. The control strategy is finally compared to other state-of-the-art controllers on a numerical district heating example.
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| 8. |
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| 9. |
- Agner, Felix, et al.
(författare)
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Fair heat distribution under deficits in district heating networks
- 2021
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In order to improve the energy efficiency in district heating networks and the comfort of their customers, these networks need to overcome the problem of unfair heat distribution under heat deficits. This paper introduces a new strategy to achieve this thermal fairness objective: it is lowcost in terms of communication and computation. The proposed approach is illustrated on a simulation example.
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| 10. |
- Agner, Felix, et al.
(författare)
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Hydraulic Parameter Estimation in District Heating Networks
- 2023
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Ingår i: IFAC PaperOnLine. - 9781713872344 ; 56, s. 5438-5443
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Konferensbidrag (refereegranskat)abstract
- Using hydraulic models in control design in district heating networks can increase pumping efficiency and reduce sensitivity to hydraulic bottlenecks. These models are usually white-box, as they are obtained based on full knowledge of the district heating network and its parameters. This type of model is time-consuming to obtain, and might differ from the actual behavior of the system. In this paper, a method is proposed to obtain a grey-box hydraulic model for tree-shaped district heating systems: hydraulic parameters are estimated based on pressure measurements in only two locations. While previous works only estimate parameters related to pressure losses in pipes, this work also includes customers valves in the grey-box model structure, an important inclusion for control-oriented applications. Finally, a numerical example illustrates the proposed method on a small district heating network, showing its ability to obtain an accurate model on the basis of noisy measurements.
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