| 1. |
- Abdollahpouri, Mohammad, 1985, et al.
(författare)
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Adaptive vibration attenuation with globally convergent parameter estimation
- 2019
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Ingår i: Mechanical Systems and Signal Processing. - : Elsevier BV. - 0888-3270 .- 1096-1216. ; 114, s. 512-527
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Tidskriftsartikel (refereegranskat)abstract
- Parameter estimation problems can be nonlinear, even if the dynamics are expressed by a linear model. The extended Kalman filter (EKF), even though it is one of the most popular nonlinear estimation techniques, may not converge without sufficient a priori information. This paper utilizes a globally convergent nonlinear estimation method the double Kalman filter (DKF) for a vibrating cantilever beam. A globally valid linear time-varying (LTV) model is required by the first stage of the DKF depending on some conditions on input and output excitation. Without considering noise, this LW model provides the first stage and is globally equivalent to the nonlinear system. Since the neglected input and output noises can degrade the quality of estimation, the second stage linearizes the nonlinear dynamics, utilizing the nominally globally convergent estimate of the first stage, and improves the quality of estimation. Both estimation methods were applied to a cantilever beam setup in real-time. An adaptive linear quadratic regulator utilizes the estimated parameters to attenuate unknown transient disturbances. Different scenarios have been explored, providing a fair comparison between EKF and DKF. These methods have been implemented on an embedded ARM-based microcontroller unit and illustrates improved convergent properties of the DKF over the EKF. The global stability of the DKF is verified and it has been observed that it needs twice the computational cost of the EKF.
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| 2. |
- Mikuláš, Erik, et al.
(författare)
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Identification and modeling of a nonlinear vibrating beam for real-time control and estimation
- 2018
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Ingår i: 25th International Congress on Sound and Vibration 2018, ICSV 2018: Hiroshima Calling. - 9781510868458 ; 2, s. 874-881
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Konferensbidrag (refereegranskat)abstract
- The real-time implementation of control and estimation algorithms on microcontrollers with limited memory and computational power requires a model that describes the dynamics of the vibrating system in sufficient detail, yet makes real-time deployment on sampled systems feasible. While extracting a model from finite element analysis is always possible, this approach yields models that are too complex to be evaluated in sample timing that is typical for vibration phenomena. In case of nonlinear vibrations, this is even more critical as state-of-the-art optimal control and estimation algorithms will have to evaluate a non-convex objective function. This paper introduces the modeling and system identification procedure of a nonlinear vibrating beam that results a real-time feasible mathematical model. Position and velocity measurements are made on a slender vibrating beam mounted equipped with a tip mass on a linear excitation stage using non-contact laser Doppler vibrometry. The measurement results are then fitted to two model candidates by using genetic algorithms to identify unknown parameters. Models are verified in simulation and their outputs are compared to experimental measurements.
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