Control
M. Mousavi; M. Ayati; M.R. Hairi-Yazdi; S. Siahpour
Abstract
Background and Objectives: In this paper, a novel linear parameter varying (LPV) model of a wind turbine is developed based on a benchmark model presented by Aalborg University and KK-electronic a/c. The observability and validity of the model are investigated using real aerodynamic data.Methods: In ...
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Background and Objectives: In this paper, a novel linear parameter varying (LPV) model of a wind turbine is developed based on a benchmark model presented by Aalborg University and KK-electronic a/c. The observability and validity of the model are investigated using real aerodynamic data.Methods: In addition, a robust fault detection and reconstruction method for linear parameter varying systems using second-order sliding mode observer is developed and implemented on the linear parameter varying model. The fault signal is reconstructed using a nonlinear term named equivalent output error injection during sliding motion and a proper transformation. The effect of uncertainties and incorrect measurements are minimized by employing an oriented method that requires solving a nonlinear matrix inequality. During numerical simulations, an actuator fault in the pitch system is considered and the performance of the method in fault reconstruction is investigated.Results: Wind speed range is considered from 14 m/s to 16 and it is regarded as a stochastic input exerting aerodynamic torque. Fast and accurate fault reconstruction happens in 0.6 seconds with less than one percent error. The observer performance is not affected by the fault and fault is estimated in 2.5 seconds with an error smaller than 2.48 percent.Conclusion: Results illustrate fast and accurate fault reconstruction and accurate state estimations in the presence of actuator fault.
Control
H. Chenarani; M.M. Fateh
Abstract
Background and Objectives: This paper presents a robust passivity-based voltage controller (PBVC) for robot manipulators with n degree of freedom in the presence of model uncertainties and external disturbance.Methods: The controller design procedure is divided into two steps. First, a model-based controller ...
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Background and Objectives: This paper presents a robust passivity-based voltage controller (PBVC) for robot manipulators with n degree of freedom in the presence of model uncertainties and external disturbance.Methods: The controller design procedure is divided into two steps. First, a model-based controller is designed based on the PBC scheme. An output feedback law is suggested to ensure the asymptotic stability of the closed-loop error dynamics. Second, a regressor-free adaptation law is obtained to estimate the variations of the model uncertainties and external disturbance. The proposed control law is provided in two different orders.Results: The suggested controller inherits both advantages of the passivitybased control (PBC) scheme and voltage control strategy (VCS). Since the proposed control approach only uses the electrical model of the actuators, the obtained control law is simple and also has an independent-joint structure. Moreover, the proposed PBVC overcomes the drawbacks of torque control strategy such as the complexity of manipulator dynamics, practical problems and ignoring the role of actuators. Moreover, computer simulations are carried out for both tracking and regulation purposes. In addition, the proposed controller is compared with a passivity-based torque controller where the simulation results show the appropriate efficiency of the proposed approach.Conclusion: The robust PBVC is proposed for EDRM in presence of external disturbance. To the best of our knowledge, it is the first time that a regressorfree adaptation law is obtained to approximate the lumped uncertainties according to the passivity-based VCS. Moreover, the electrical model of the actuators is utilized in a decentralized form to control each joint separately.
