A challenge in the design of adaptivecontrol laws for uncertain dynamical systems is to achieve system stability and a prescribed level of command following performance in the presence of actuator dynamics. It is wel...
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A challenge in the design of adaptivecontrol laws for uncertain dynamical systems is to achieve system stability and a prescribed level of command following performance in the presence of actuator dynamics. It is well-known that if the actuator dynamics do not have sufficiently high bandwidth, their presence cannot be practically neglected in the design since they limit the achievable stability of adaptivecontrol laws. In this paper, we consider the design of model reference adaptive control laws for uncertain dynamical systems in the presence of high-order actuator dynamics. Specifically, a linear matrix inequalities based hedging approach is proposed, where this approach modifies the ideal referencemodel dynamics to allow for correct adaptation that is not affected by the presence of actuator dynamics. The stability of the modified referencemodel is then computed using linear matrix inequalities, which reveals the fundamental stability interplay between the parameters of the actuator dynamics and the allowable system uncertainties. In addition, we analyze the convergence properties of the modified referencemodel to the ideal referencemodel. The presented theoretical results are finally illustrated through a numerical example. (C) 2018 Elsevier Ltd. All rights reserved.
This paper presents a novel model reference adaptive control (MRAC) of five-phase interior permanent magnet (IPM) motor drives. The primary controller is designed based on artificial neural network (ANN) to simulate t...
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The presence of state and control constraints in physi cal systems may lead to performance deterioration and instability if not adequately accounted for in controller design processes. Therefore, a procedure of state ...
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ISBN:
(纸本)9780889868632
The presence of state and control constraints in physi cal systems may lead to performance deterioration and instability if not adequately accounted for in controller design processes. Therefore, a procedure of state and control constraint fulfillment for uncertain linear systems, which firstly require an adaptivecontroller, is proposed. model reference adaptive control (MRAC) Method is selected to design the controller, and Lyapunov stability theory is used to obtained adaptive laws. To solve the constraint fulfillment problem, a concept of maximal output admissible set [8], [11] is utilized to predict safe operation of the plant. Constraint fulfill ment procedure is described as polynomial optimization problems, and a numerical design example is carried out to support the arguments.
Hybrid electric vehicles (HEVs) equipped with dual clutch transmission (DCT) can benefit from engine auxiliary braking force and driving motor regenerative braking force in braking conditions. This can effectively red...
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Hybrid electric vehicles (HEVs) equipped with dual clutch transmission (DCT) can benefit from engine auxiliary braking force and driving motor regenerative braking force in braking conditions. This can effectively reduce the workload of hydraulic mechanical braking systems and recovery braking energy, which will improve the fuel economy. In the downshift process, the driving motor is involved to response the change of torque/speed demand, which can further improve the shift quality of DCT without affecting the engine emissions and fuel economy. The combined braking condition of HEVs with DCT allows for the variation of power distribution between the front and rear axle, as well as the electric and hydraulic braking force. In this study, the downshift decision strategy is designed based on the two-parameter shift schedule, while considering the driver's subjective driving intention. Subsequently, the mathematical model developed to investigate the downshift process of HEVs with dual clutch transmission has been applied to skip downshift process, to analyze the control sequence and implement different control algorithms according to respective control objects. Specifically, the sliding mode variable structure optimization control algorithm is used to allow the engine speed to track the target value in the torque phase. In addition, the linear quadratic tracking controller and the modelreferenceadaptive system are used, based on adjustable parameters, to realize the speed synchronization of the clutch driving and driven plate in the inertial phase. According to the results of electro-hydraulic braking force distribution, the braking forces of an integrated starter generator (ISG) motor and hydraulic brake system are controlled to switch to the demand level. Then, the simulation model established on a Matlab/Simulink platform is used to validate the skip downshift control strategy. Finally, the designed control strategies are verified on the test bench. The test resul
This paper presents the properties of two fractional order error models (FOEM) that arise in the analysis of fractional order adaptive systems (FOAS). Cases where the fractional order is the same for every equation in...
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This paper presents the properties of two fractional order error models (FOEM) that arise in the analysis of fractional order adaptive systems (FOAS). Cases where the fractional order is the same for every equation in these two FOEM were analyzed in a previous work, obtaining useful results. However, those cases where the fractional orders are different in the equations of FOEM (mixed order cases) have not been addressed before. This paper treats the analysis of some of these mixed order cases, proving boundedness of all the signals and convergence to zero of the mean value of the squared norm of the output error. A model reference adaptive control (MRAC) scheme for an integer order plant using fractional adaptive laws for estimating the controller parameters is presented at the end of the paper, which shows the applicability and importance of the proposed results.
An important issue in robust adaptivecontrol is the estimation of realistic ranges for the parametric uncertainty to be used in the projection mechanism with the goal of guaranteeing the boundedness of the adaptive p...
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An important issue in robust adaptivecontrol is the estimation of realistic ranges for the parametric uncertainty to be used in the projection mechanism with the goal of guaranteeing the boundedness of the adaptive parameters in the presence of modeling uncertainty. To facilitate this design it is common practice to assume conservative parameters' projection bounds and to use high-gain adaptation for reducing tracking errors. However, this approach may not be suitable in practical applications because it might potentially lead to unpredictable transients and peaking phenomena. Therefore, the determination of tighter uncertainty upper bounds is a fundamental problem toward the design of safe adaptivecontrollers. This study shows that the problem of estimating the parametric uncertainty domain of a linearly parameterized adaptivecontroller can be advantageously formulated as a linear interval prediction model identification problem. On this basis a practical data-driven method to compute tight upper bounds for the uncertain parameters is proposed through the solution of a convex constrained optimization problem expressed in terms of linear matrix inequalities. The proposed method has been applied to the design of a longitudinal and a lateral directional model reference adaptive control for a fleet of YF-22 research unmanned aerial vehicles based on real flight data.
In this work, we consider the application of a special type of neural networks based on radial basis functions (RBF) which belongs to a class of associative memory neural networks. The RBF neural network is used in a ...
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The occurrence of shimmy vibration in aircraft nose landing gear can cause an increase of fatigue stress on the nose landing gear mechanical elements that can eventually lead to high wearing of components as well as t...
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The occurrence of shimmy vibration in aircraft nose landing gear can cause an increase of fatigue stress on the nose landing gear mechanical elements that can eventually lead to high wearing of components as well as to severe damage of the leg, giving raise to safety issues. The use of the Modified Simple adaptivecontroller is investigated for the realization of an adaptive shimmy suppression system. The nonlinear governing equations that model the shimmy vibration behavior of an aircraft nose landing gear are first linearized in order to synthesize the adaptivecontroller, while nonlinear terms are then taken into account as disturbances. The almost strict passivity of the plant is obtained by using a parallel feedforward compensator. The parallel feedforward compensator is designed as the inverse of a stabilizing controller while the Modified Simple adaptivecontroller is tuned by considering the minimization of some dynamic performance parameters as design requirements. The influence of the advancing speed on the controlled plant response is studied by simulating scenarios of aeronautical interests.
The problem of constructing a model reference adaptive control law for an uncertain 1- dimensional parabolic system with one constant coefficient is considered in this paper. adaptivecontrol law are obtained by Lyapu...
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The problem of constructing a model reference adaptive control law for an uncertain 1- dimensional parabolic system with one constant coefficient is considered in this paper. adaptivecontrol law are obtained by Lyapunov redesign method. The energy method for parabolic systems and the Agmon's inequality are applied in the analysis, which leads to a stronger result than that of Hong and Bentsman (Automatica, 1994).
This paper addresses the problem of a multirotor carrying an unknown suspended payload, allowed to swing in one axis. The payload is unknown in the sense that its parameters, such as the payload mass and cable length,...
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This paper addresses the problem of a multirotor carrying an unknown suspended payload, allowed to swing in one axis. The payload is unknown in the sense that its parameters, such as the payload mass and cable length, are unknown and its state, the swing angles, are not available for measurement. The suspended payload alters the flight dynamics of the vehicle considerably and the flight controllers need to minimize this effect. A robust model reference adaptive control technique is designed and implemented to minimize the effect of the suspended payload on the vehicle while allowing the controller to adapt to account for the unknown payload. The controller is modified to reject external disturbances and to be robust in the presence of sensor noise and drift. In simulation, this technique proves to dampen the oscillations caused by the payload. A quadrotor was built to practically demonstrate the effectiveness of the controller. The PX4 flight control stack is considered for the firmware of the vehicle. The model reference adaptive controller was implemented and succeeded to dampen the oscillations caused by the payload in a practical flight.
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