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EPS (electric power-assisted steering) system has been used to replace traditional hydronic power steering system in vehicles. In an EPS system, the assisting torque is from an electric motor for steering effort. The performance of an EPS system requires that the high frequency external disturbance in road reaction torque be attenuated so that the driver could feel comfortable - light and less vibration...
This paper presents an efficient numerical method to obtain optimal PI tuning formulae for first order plus dead time processes. The design method is based on optimal load disturbance rejection. In order to obtain a robust controller, a constraint on the maximum sensitivity is used. In addition, the design method deals with setpoint response using a two degree of freedom structure. In order to show...
A new method for real-time calculation of constrained nonlinear optimal control problems is proposed. The proposed method is based on the iterative algorithms for obtaining the numerical solutions of optimal control problems. In this paper, we adopt the Riccati-equation based algorithm, one of the iterative algorithms, and demonstrate the proposed 'algorithmic controller' is applicable to the swing-up...
The paper presents a method for energy efficiency analysis of servo pneumatic actuator systems. Simulation study indicated that different quantities of compressed air were consumed for one cycle of piston movement when the same controller is adopted but with different profiles for servo pneumatic actuators. This motivated the authors to investigate the profile which leads the system to use the least...
A nonlinear adaptive-robust scheme is presented to control a class of nonlinear systems. It effectively combines the design techniques of adaptive and robust control to improve performance by retaining the advantages of both techniques. It enhances transient performance and eliminates robustness problems compared to a parameter adaptive control. It also improves tracking performance by reducing modeling...
We consider the optimal control of feedback linearizable dynamical systems subject to mixed state and control constraints. In general, the optimal control does not linearize the dynamics. Such problems frequently arise in astronautical applications where stringent performance requirements demand optimality that cannot be achieved by feedback linearizing controls. We prove that a sequence of solutions...
This paper demonstrates a good application of SDRE technology to propose optimal controllers for a flexible transporter system with arbitrarily varying lengths. A model for a flexible cable transporter system with varying cable lengths is developed using Hamilton's principle. Galerkin's method is applied to transform the infinite dimensional system into a set of finite dimensional ordinary differential...
In this paper, a planar waypoint guidance synthesis for missiles or unmanned aerial vehicles using the optimal impact-angle-control laws is proposed. The energy optimal trajectory optimization problem with waypoint constraints can be converted to an unconstrained optimization problem of finding the optimal waypoint pass angles for the energy impact-angle-control laws. These optimal waypoint pass angles...
Intended for being used in legged robots, a specially designed nonlinear actuator, dual smart drive, which offers continuously changing transmission ratio and dual properties, and that is very suitable for situations where the same drive is required to perform two different types of start-stop motions of the mobile link, is introduced. Then, the associated control problem to this nonlinear actuator...
In the model predictive control (MPC) framework a controller is computed using a finite horizon optimal control cost. When linear constraints are imposed on the system with a quadratic cost function, then the MPC problem can be reformulated as a constrained quadratic programming (QP) problem. In this paper active set methods are used in order to solve the QP problem associated with MPC, and it is...
This paper describes the development of a control system used for the active shape control of inflatable space structures. The genetic algorithm is utilized for the optimization of control variables. A vision system is implemented for the measurement of the structure shape. Shape memory alloy wire actuators are used to exert the obtained optimal tensions. The developed control system is then tested...
A trade-off between voltage regulation and power oscillation damping is achieved by cooperative effort of excitation and STATCOM in this paper. This end is embodied by a predefined linear quadratic regulator (LQR) performance index. Since, in practical power systems, decentralized control is highly desirable for its relatively low cost and high reliability, the controller designing procedure is formulated...
This paper presents a reduced-order state-function/unknown input observer for linear unknown input systems with additional Hinfin performance. The proposed reduced-order observer can be designed under a less strict existence condition. The control scheme which can be estimated unknown inputs and decoupled disturbance, simultaneously, is also proposed, and is applied to disturbance attenuation problems...
This paper presents the design of two reduced order linear parameter-varying controllers with guaranteed Hscrinfin, performance for lateral driving assistance. The uncertainties considered consist in road adhesion, the mass of the vehicle and the driver dynamics. The lateral controller adds a steering torque to that of the driver in order to improve lane keeping and yaw dynamic under external disturbances...
This paper deals with an Hscrinfin DIA control system design of a magnetic bearing considering periodic disturbance. Hscrinfin control problem which treats a mixed disturbance and an initial state uncertainty attenuation (DIA) control is expected to provide a good transient property, and we confirmed that DIA control has a good rotational performance by some experiments. On the other hand, active...
This paper deals with the problem of reliable control for linear systems with uncertainty in all system matrices as well as actuator failures. The goal is to design a constant state feedback controller that provides robust stability and Hinfin, performance for all admissible uncertainties and actuator failures. It is assumed that the parameter uncertainties are norm bounded and the actuator failures...
This paper applies model based predictive control (MFC) to the scheduling problem in routers to guarantee QoS in DiffServ architecture. Model predictive control is a form of control in which the current control action is obtained by solving a finite horizon open-loop optimal control problem at each sampling interval. It intrinsically supports constraints handling and smoothens the control action over...
This study compares three linear optimal controllers for stationkeeping with respect to reference orbits around Phobos. The dynamics of the Mars-Phobos system are constrained to the synodical plane of the circular restricted three-body problem (CRTBP) with Phobos modelled as an ellipsoid. The controllers rely on periodic orbits which permit the dynamics to be expressed as a linear system with periodic...
In this paper the optimal nonlinear predictive control structure with integral action is presented, which provides asymptotic tracking of smooth reference trajectories and robustness to parameters uncertainties. The controller is based on a finite horizon continuous time minimization of nonlinear predicted tracking errors. A key feature of the control law is that its implementation does not need to...
This paper suggests a constrained Hinfin control scheme for T-S fuzzy systems with control and output constraints. The control law is in the form of so-called parallel distributed compensation (PDC) which are essentially nonlinear dynamic feedback controllers. Under the bound assumption of the disturbance energy, we can seek an ellipsoid containing all perturbed trajectories, then time-domain hard...
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