1,721,058 research outputs found
Employment of Magneto-Rheological Semi-Active Differential in a Front Wheel Drive Vehicle: Device Modelling and Software Simulations
No full textImplementation and Validation of a Hybrid Testing Procedure for Base-Isolated Structures
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Accurate state estimation for a hydraulic actuator via a SDRE nonlinear filter
No full textThe state estimation in hydraulic actuators is a fundamental tool for the detection of faults or a valid alternative to the installation of sensors. Due to the hard nonlinearities that characterize the hydraulic actuators, the performances of the linear/linearization based techniques for the state estimation are strongly limited. In order to overcome these limits, this paper focuses on an alternative nonlinear estimation method based on the State-Dependent-Riccati-Equation (SDRE). The technique is able to fully take into account the system nonlinearities and the measurement noise. A fifth order nonlinear model is derived and employed for the synthesis of the estimator. Simulations and experimental tests have been conducted and comparisons with the largely used Extended Kalman Filter (EKF) are illustrated. The results show the effectiveness of the SDRE based technique for applications characterized by not negligible nonlinearities such as dead zone and frictions
ASME 2012 - 11th Biennal Conference on Engineering Systems Design and Analysis (ESDA 2012)
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Actuator dynamics compensation for real-time hybrid simulation: an adaptive approach by means of a nonlinear estimator
No full textIn real-time hybrid simulation, hydraulic actuators, equipped with suitable controllers, are typically used to impose displacements to experimental substructures. Interaction between actuators and physical substructures can result in a nonlinear behaviour of the overall experimental testing system (ETS), making the controller design very challenging. The accuracy of the hydraulic actuation system (HAS) is very crucial because actuator displacement errors lead to incorrect simulation results. For this purpose, several methods have been developed by researchers in order to compensate tracking error of HASs. This paper presents a novel adaptive compensator that takes into account the actual ETS dynamics by adopting an extend Kalman filter for the real-time estimation of the ETS model parameters. The adaptive approach improves the actuator control accuracy and avoids ad hoc system identification procedures. The novel compensator has been verified experimentally on a test rig for seismic isolator shear tests. The feasibility of the proposed compensation method has been also demonstrated through real-time hybrid simulation of a building with a base isolation system. Both numerical and experimental results confirmed that the proposed compensation strategy provides good results even in the case of inevitable nonlinearities of the ETS. Furthermore, the method has also demonstrated good performance in terms of stability and robustness with respect to variations of the operating conditions
Riccati equation based nonlinear filter: A case study for hydraulic actuators in the presence of dead-zone
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