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RF pulse flattening in the SwissFEL facility based on model-free iterative learning control
(2015)Proceedings of the 36th International Free Electron Laser Conference (FEL2014)This paper introduces an iterative approach to producing flat-topped radio frequency (RF) pulses for driving the pulsed linear accelerators in the Swiss free electron laser (SwissFEL). The method is based on model-free iterative learning control which iteratively updates the input pulse shape in order to generate the desired amplitude and phase pulses at the output of the RF system. The method has been successfully applied to the klystron ...Conference Paper -
Model-based klystron linearization in the SwissFEL test facility
(2015)Proceedings of the 36th International Free Electron Laser Conference (FEL2014)An automatic procedure is developed to provide the optimal operating point of a klystron. Since klystrons are non-linear with respect to the input amplitude, a model-based amplitude controller is introduced which uses the klystron characteristic curves to obtain the appropriate high voltage power supply setting and amplitude, such that the operating point is close to the saturation. An advantage of the proposed design is that the overall ...Conference Paper -
Robust adaptive model predictive building climate control
(2017)IFAC-PapersOnLine ~ 20th IFAC World Congress. ProceedingsModel Predictive Control (MPC) is a promising algorithm for building climate control. However, the construction of an accurate building model is very challenging since identification experiments on buildings are, due to time and usage constraints, difficult to conduct and the construction data are often only known approximately. This paper proposes the use of a recently developed robust, adaptive MPC as a possible solution for handling ...Conference Paper -
Beam-Based Power Distribution Over Multiple Klystrons in a Linear Accelerator
(2015)Proceedings of the 6th International Particle Accelerator Conference (IPAC 15)A linear accelerator including several klystron driver RF stations can be viewed as a single virtual RF station with a certain accelerating RF voltage (in amplitude and phase). This paper develops an optimization scheme that, for a specified beam energy gain, determines the klystrons output powers and the modulators high voltages optimally. The algorithm employs the klystron nonlinear static characteristics curves to calculate the input ...Conference Paper -
Pulse Compressor Phase and Amplitude Modulation Based on Iterative Learning Control
(2015)Proceedings of the 6th International Particle Accelerator Conference (IPAC 15)This paper presents an alternative way to produce flat-topped RF pulses at the pulse compressor output. Flat-topped RF pulses are suitable for multi-bunch operation where it is often required that beams experience the same accelerating gradient. Moreover, the energy gain, in this case, is less sensitive to timing jitters. The proposed approach is based on Iterative Learning Control technique, which iteratively updates the input waveforms, ...Conference Paper -
On the optimal control problem for a class of monotone bilinear systems
(2016)Proceedings of the 22nd International Symposium on Mathematical Theory of Networks and SystemsWe consider a class of positive systems in which the control signal enters bilinearly with the state. Such dynamics arise naturally, for example, from modeling the evolutionary dynamics of HIV in the presence of drug therapy. For this class of system, we formulate an infinite horizon optimal control problem and show that the optimal control signal is constant over time. We further extend our results to the case of uncertain dynamics and ...Conference Paper -
Modeling, Identification and Control of Building Thermal Systems
(2014)Proceedings of the COLEB 2014 Workshop: Computational Optimisation of Low-Energy BuildingsIn this paper we report on our work in the past years on model predictive control of office buildings with focus on experimental applications and the modeling of buildings.Conference Paper -
A framework for distributed control based on overlapping estimation for cooperative tasks
(2017)IFAC-PapersOnLine ~ 20th IFAC World Congress. ProceedingsWe present a framework for distributed control where the subsystems estimate overlapping components of the state of the overall system. This enables the implementation of decentralized state feedback controllers, which depend on the overlapping state estimates. For a distributed framework, communication can be added. By choosing the amount of communication and the degree of overlap in the state estimates, a trade-off between increasing ...Conference Paper -
Modeling, Identification, Estimation and Adaptation for the Control of Power-Generating Kites
(2018)IFAC-PapersOnLine ~ 18th IFAC Symposium on System Identification, SYSID 2018. ProceedingsLarge-scale kites, flying high-force crosswind trajectories, have been proposed for wind power generation. A two phase operational cycle generates net positive power using a ground-based motor/generator. In the traction phase the kite flies a high-force trajectory while reeling out the generator-connected tethers. A low-force retraction phase reels in the tethers and returns the kite to the start of the cycle. Highly variable conditions ...Conference Paper -
Adaptive model predictive control for constrained MIMO systems
(2013)IFAC Proceedings Volumes ~ 11th IFAC International Workshop on Adaptation and Learning in Control and Signal Processing (ALCOSP 2013)An adaptive output feedback control algorithm for constrained multiple input multiple output linear systems is proposed, able to cope with input and output constraints, output disturbances and measurement noise. The approach relies on a real-time set membership identification algorithm to provide bounds on the predicted plant outputs. These bounds are exploited in a receding horizon control strategy that guarantees recursive satisfaction ...Conference Paper