Papers by Keyword: Singular Perturbation

Abstract: A dynamic model in singular perturbation form is established for the deformation and vibration of rigid-flexible coupling mechanical system due to the drive force, inertia force and gravity. This model is divided into slow subsystem and fast subsystem. A PD controller is designed for slow subsystem while optimal controller for fast subsystem and a composite controller is developed based on this. The validity of the composite controller is verified through MATLAB simulation with a flexible scissor-like deployable mechanism as an example. The results can be used in control of CNC machine, robot, spatial mechanism etc.

Abstract: The singularly perturbed systems for the nonlinear three-species food-chain reaction systems with time delay are considered. By using the method of the stretched variable, the formal asymptotic solution is obtained under suitable conditions.

Abstract: Aiming at flexible folding boom of the lorry cranesuppress the beam vibration while track a desired trajectory, the paperdesigns a composite control method based on the singular perturbation theory. The flexible multi-body dynamics equation of the flexible folding arm was established by the Lagrange equations and assumed mode method. The system was decomposed intorigid motion (slowly varying system) and flexible vibration (fastvariable system). Fuzzy PID control was designed to track the flexible arm’s rigid motion trajectory control and the linear quadratic optimal controlwas designed to suppress the elastic vibration. The simulation in Simulink results show that the composite control method can control the folding arm effectively.

Abstract: This paper concerns the problem of regulating the frequencies of the evolving electric energy systems. The currently implemented frequency regulation approach is found unable to relieve the impact of the increasingly integrated variable sources such as renewable power plants and price responsive loads. Even several key underlying assumptions of this approach are not likely to hold in this situation. In this paper we propose an enhanced frequency regulation approach by differentiating units participating in frequency regulation both with respect to their location and ability to respond. This approach models the governorturbine-generator dynamics of each individual generator and develops a linearized model of the interconnected power system. Moreover, the singular perturbation technique is employed to reduce the unnecessary complexity of the linear system and simplify the control design. An optimal feedback control law is then designed based on the reduced order model via Linear Quadratic Regulator method. Comparative simulations on a 3bus test power system show the improved control performance obtained by the proposed approach.

Abstract: In this paper a kind of quasi-linear singular perturbed problems with infinite initial conditions is investigated. The existence and uniqueness of the solution are proved.Therefore the asymptotic analysis of the solution can be obtained.

Abstract: Dynamic inversion and singular perturbation methods are employed for medium-range air-to-air missile to obtain a near-optimal midcourse guidance law. The midcourse guidance stage is separated into two phases. In phase 1, which the rocket engine working, a dynamic inversion guidance law is used to guide the missile flight along a nominal trajectory. In the second gliding phase, singular perturbation technique is employed to develop a guidance law which maximum terminal specific energy. A terminal correction is made to ensure the seeker intercept the target. The result obtained from numerical simulation shows that, the guidance law can conserve energy for terminal interception, and the flight path error is small enough at the end of midcourse stage.

Abstract: A composite controller is designed based on the singular perturbation model of single-link flexible manipulators. A dynamic sliding mode controller is designed for the slow subsystem, and optimal controller is designed to stabilize the fast subsystem. Numerical simulation results confirm that the proposed controller not only can perform fast and accurate tracking, but also can reduce the chattering of the sliding-mode control, and the proposed controller can suppress the tip vibration of the flexible manipulator effectively.

Abstract: The information of boundary condition in the contact interface reflected complex properties of visco-elastic material with various contact conditions. Numerical results and the asymptotic estimates were calculated. It is presented by the software which are consistent with the boundary-layer analysis in our previous papers. In this paper, the application of computer simulating and related numerical result on the contact boundary-layer has been discussed. Numerical results were calculated (by using HPC platform, NAG toolbox for Matlab) and shown by use of the software i.e. LS-DYNA. The numerical scheme yields the convergent finite element analysis (FEA) solution and stable semi-discrete Galerkin-ADI (G-ADI) iteration.

Abstract: In this paper the digital controller design for vehicle suspension system, based on a half-car model using singular perturbed systems is considered. This strategy is based on the slow and fast subsystems controller design. The simulation results show them favorable performance of the controller and achieve fast and good response.