Physical limits of real control systems, such as force saturations and state variable constraints, if attained during the motion, may cause actuator damages, loss of control effectiveness or even a dynamic instability...
详细信息
Physical limits of real control systems, such as force saturations and state variable constraints, if attained during the motion, may cause actuator damages, loss of control effectiveness or even a dynamic instability. In order to overcome these drawbacks and improve the overall reliability of the control policy without turning to uneconomic designs, it might be convenient to account for physical limitations directly in the control law. This philosophy is embraced in this paper, where a general approach is presented based on the tool of the state-dependent Riccati equation, in the general framework of nonlinear regulation. The proposed formulation is meant to be feasible to handle limitations on both statevariables and control forces. This general control strategy is then specialized to the case of a seismically excited multi-storey frame structure equipped with an active mass damper subjected to actuator saturation and stroke limitation. In-depth numerical simulations are also performed in order to investigate the effectiveness of the proposed approach, for different levels of constraint severities, and its robustness against unknown random variations of structural parameters, also in the case of incomplete number of sensors, measurements affected by noise and the presence of process disturbances. Copyright (c) 2011 John Wiley & Sons, Ltd.
For the orientation control system of the manipulator's end effector with electrical actuators, we develop a decomposition pr ocedure of feedback law design to track given trajectories in the end effector's co...
详细信息
For the orientation control system of the manipulator's end effector with electrical actuators, we develop a decomposition pr ocedure of feedback law design to track given trajectories in the end effector's coordinate system. Owing to the S-shaped smooth sigma-functions used as the local feedback laws and corrections of the state observer, the tracking system is invariant with a given accuracy with respect to existing uncertainties under constraints imposed on the variables of the mechanical subsystem. The suggested approach does not involve the solution of the inverse kinematics and dynamics problems and also relaxes the requirements to the volume of a priori information about the plant and external perturbations.
A maximum principle is obtained for control problems involving a constant time lag τ in both the control and statevariables. The problem considered is that of minimizing ...
详细信息
A maximum principle is obtained for control problems involving a constant time lag τ in both the control and statevariables. The problem considered is that of minimizing
$$I(x) = \int_{t^0 }^{t^1 } {L (t,x(t), x(t - \tau ), u(t), u(t - \tau )) dt} $$
subject to the constraints
1
$$\begin{gathered} \dot x(t) = f(t,x(t),x(t - \tau ),u(t),u(t - \tau )), \hfill \\ x(t) = \phi (t), u(t) = \eta (t), t^0 - \tau \leqslant t \leqslant t^0 , \hfill \\ \end{gathered} $$
1
$$\psi _\alpha (t,x(t),x(t - \tau )) \leqslant 0,\alpha = 1, \ldots ,m,$$
1
$$x^i (t^1 ) = X^i ,i = 1, \ldots ,n$$
. The results are obtained using the method of Hestenes.
Three augmented penalty function algorithms are tested and compared with an ordinary penalty function algorithm for two demonstration optimal control problems. Although the augmented penalty function is quite helpful ...
详细信息
Three augmented penalty function algorithms are tested and compared with an ordinary penalty function algorithm for two demonstration optimal control problems. Although the augmented penalty function is quite helpful in solving control problems with terminal stateconstraints, the convergence can be improved significantly by providing systematic increases in the penalty constant.
In this paper, an embedding theorem is established for a system of nonlinear integral equations of the Volterra type. The main result is basic in the development of a maximum principle for an optimal control problem i...
详细信息
In this paper, an embedding theorem is established for a system of nonlinear integral equations of the Volterra type. The main result is basic in the development of a maximum principle for an optimal control problem in which the statevariables are determined as solutions to integral equations.
Space shuttle trajectory design requires the optimization of highly-constrained, branched, atmospheric trajectories. This paper presents a general mathematical model for trajectory optimization incorporating multiple ...
详细信息
Space shuttle trajectory design requires the optimization of highly-constrained, branched, atmospheric trajectories. This paper presents a general mathematical model for trajectory optimization incorporating multiple simulation sections, statevariable discontinuities, subarc elimination, branching, and six types of equality and inequality constraints. A solution is sought using a nonlinear programming approach based on SUMT, the sequential unconstrained minimization technique. Results of the numerical solution of a highly constrained space shuttle reentry problem are presented.
In industrial process, especially in chemical process control, controlled process has the characteristic of many intermediate statevariables. The problem of how to handle the amplitude constraints of input, output an...
详细信息
ISBN:
(纸本)9789881563811
In industrial process, especially in chemical process control, controlled process has the characteristic of many intermediate statevariables. The problem of how to handle the amplitude constraints of input, output and some important statevariables, which commonly exists in process control, is the nodus of current researches. Model Predictive Control (MPC) can bring the constraints of input, output variables into the optimization problem, which is solved on-line to obtain the control law. With this advantage MPC is superior to other control methods to control constrained system. However, the disposal of amplitude constraint of important statevariables in current MPC algorithms, usually consider it as one part of constraints of output variables, increases the number of controlled variables. A new zone predictive control algorithm is presented in this paper to deal with the constraint of important statevariables This new algorithm transforms constraint of important statevariables to matrix inequality form of input increment on-line, and brings it into the optimization problem for obtaining the control law. In the end, simulation results of control problem about side-stream quality of crude tower show the effectiveness and feasibleness of the proposed algorithm.
暂无评论