Regulator problem for linear continuous-time delay systems withnonsymmetrical constrained control

The regulator problem is studied for linear continuous-time delay systems with nonsymmetrical constrained control. Necessary and sufficient conditions allowing the autors to obtain the largest nonsymmetrical polyhedral positively invariant with respect to (w.r.t.) the system in the closed loop are given, The case of symmetrical constrained control is obtained as a particular case     

Piecewise linear constrained control for continuous-time systems

In the control of linear systems with nonsymmetrical input constraints, larger domains of initialization can be obtained by allowing slow initial dynamics of the system in closed loop and making it faster during its evolution. The positive invariance concept application leads to a piecewise linear constrained control using nonsymmetrical nested polyhedral sets     

Constrained regulation of linear discrete-time systems with time delay: Delay-dependent and delay-independent conditions

The regulator problem is studied for discrete-time delay systems with asymmetrical constrained control. Necessary and sufficient conditions allowing us to obtain the largest asymmetrical polyhedral positively invariant with respect to the system in the closed loop are given. The case of symmetrical constrained control is obtained as a particular case. The results obtained can be divided into two categories. The first concerns the delay-independent positively invariant conditions and the second is the delay-dependent conditions.     

深海集矿机集矿头高度模糊PID控制

集矿头高度调节采用阀控非对称液压缸结构，是一个非线性系统。集矿头上升和下降两个方向的动态特性不一致，而且电液比例阀存在动作死区。为改善系统的动态性能，设计一个带死区补偿的非对称模糊PID控制器，实验表明这种方法不仅有效地解决了系统的不对称性，而且改善了集矿头高度调节的动态性能。     

Adaptive control and constrained control allocation for overactuated ocean surface vessels

In this article, the constrained control allocation is proposed for overactuated ocean surface vessels with parametric uncertainties and unknown external disturbances. The constrained control allocation is transformed into a convex quadratic programming problem and a recurrent neural network is employed to solve it. To complete the control allocation, the control command is derived via the backstepping method. Adaptive tracking control is proposed for the full-state feedback case using the backstepping technique and the Lyapunov synthesis. It is proved that the proposed adaptive tracking control is able to guarantee semi-global uniform ultimate boundedness of all signals in the closed-loop system. Then, the obtained control command is distributed to each actuator of overactuated ocean vessels. Finally, simulation studies are presented to illustrate the effectiveness of the proposed adaptive tracking control and the constrained control allocation scheme.     

Discrete-time interval optimal control problem

This paper proposes a new approach for the discrete-time interval optimal control problem. The optimal interval solution of discrete-time interval optimal control problem is obtained using the single-level constrained interval arithmetic coupled with a dynamic programming technique. Moreover, the optimal interval solution contains the real-valued optimal solutions. To illustrate an optimal solution for the interval case, we use the minimax regret criterion in the interval inventory control problem we present.     

On the controllability of switching linear systems

This note presents a necessary and sufficient condition for small time controllability of a linear switching system (that is, a collection of linear time-invariant control systems, where a trajectory is any concatenation of trajectories of the individual systems). This result extends the controllability condition recently obtained for unconstrained linear switching systems to the case of control which is constrained in a cone.     

轨綫两端均受限制时的最优控制问題

本文用文献[4]中的方法,首先处理了轨线两端均受限制时的快速最优控制问题,得到控制最优性的必要条件以及在某种意义下的充分条件;还得到有关微分方程的边界条件,并说明其几何意义,即贯截条件.此外,又讨论了所用方法中乘子的性质及作用. 对于一般意义下的以及文献[4]中所讨论的最优控制问题,当轨线两端均受限时,也可象此处对快速系统那样进行处理,并得到相应的结果.同时,关于贯截条件及乘子的讨论,也仍然有效. 文中附有二个算例.     

On Stability of Constrained Receding Horizon Control with Finite Terminal Weighting Matrix

In this paper, a new stabilizing receding horizon control, based on a finite input and state horizon cost with a finite terminal weighting matrix, is proposed for time-varying discrete linear systems with constraints. We propose matrix inequality conditions on the terminal weighting matrix under which closed-loop stability is guaranteed for both cases of unconstrained and constrained systems with input and state constraints. We show that such a terminal weighting matrix can be obtained by solving a linear matrix inequality (LMI). In the case of constrained time-invariant systems, an artificial invariant ellipsoid constraint is introduced in order to relax the conventional terminal equality constraint and to handle constraints. Using the invariant ellipsoid constraints, a feasibility condition of the optimization problem is presented and a region of attraction is characterized for constrained systems with the proposed receding horizon control.     

基于种群分级遗传算法的受限广义预测控制

存在约束的控制过程限制了传统GPC方法在工业领域中的广泛应用.本文利用遗传算法来解决受限GPC算法的优化问题.当控制作用突破受限条件时,启用遗传算法来处理带约束的非线性优化问题,并以此作为滚动优化策略,求得最优控制律.遗传算法采用种群分级制度,充分利用所获信息对高级种群进行初始化,大大提高了算法的局部搜索能力.同时低级...     

Adaptive Impedance Control Applied to a Pneumatic Legged Robot

An adaptive impedance control scheme with estimation of robot andenvironment parameters is proposed in this paper. It consists of two stagesof adaptation and control. The first one performs an on-line estimation ofthe robot inertial parameters, during the complete (constrained or not)motion of the leg, while the second one compensates for the uncertainties onthe characteristics of the ground (position and stiffness). Simulationresults obtained for a single leg of a pneumatic driven, quadruped robotshow the effectiveness of the proposed control scheme in case ofconsiderable uncertainty both in the robot and ground parameters.     

Regulator problem for linear discrete-time systems with non-symmetrical constrained control

The regulator problem is studied for linear discrete-time systems with non-symmetrical constrained control, i.e. systems described by the state equation x _k+1 = Ax _k + Bu _k, where u _k ? Ω, and u _k = Fx _k. Necessary and sufficient conditions allowing us to obtain the largest non-symmetrical polyhedral domain of positive invariance and contractivity with respect to motions of the system in the closed loop are established. The case of symmetrically constrained control is obtained as a particular case.     

A PSO-BASED MULTIVARIABLE FUZZY DECISION-MAKING PREDICTIVE CONTROLLER FOR A ONCE-THROUGH 300-MW POWER PLANT

Model predictive control is an available method for controlling large-lag process in power plants, but conventional constrained predictive control cannot deal with the widely existent uncertainties and nonlinearities in power plants. With the help of the fuzzy set theory, this article proposes a new constrained predictive control algorithm based on Fuzzy Decision-Making Method (FDMPC). Compared with the other traditional constrained predictive control, this new algorithm replaces the conventional objective function with the appropriate fuzzy index function. As a result, it is easy to integrate the constraints into the fuzzy index function, which can greatly reduce the complexity of the optimization. Then a new evolutionary computation method named particle swarm optimization is firstly applied into the design of a model predictive controller. Moreover, this article also demonstrates that the conventional predictive control is actually a particular case of the proposed algorithm even though in the MIMO case, so this new algorithm is an extension of the traditional constrained predictive control strategy. At last, the proposed FDMPC has been applied into a real once-through power unit model, and the simulation results have validated the good control performance of the proposed FDMPC.     

Constrained controllability of discrete-time systems†

The constrained controllability of the discrete-time system x_k+1=A(k)x_k+B(k)u,_k is considered where the control uk is termed admissible if it satisfies specified magnitude constraints. Constrained controllability is concerned with the existence of an admissible control which steers the state x to a given target set from a specified initial state

Conditions for checking constrained controllability to a given target set from a specified initial state are presented. These conditions involve solving finite-dimensional optimization problems and can be checked via numerical computation. In addition, conditions for checking global constrained controllability to a given target set are presented. A system is globally constrained controllable if for every initial state, there exists an admissible control that steers the system to the target.

If a given discrete-time system is constrained controllable, it may be desirable to obtain an admissible control that steers the system to the target from a specified initial state. Such a control is called a steering control. Results for computing steering controls are also presented

This paper is concluded with a numerical example. In this example, it is shown that the constrained controllability of a continuous-time system which has been discretized is dependent on the discretization time. The set of states which can be steered to the target changes as the discretization time changes. Furthermore, the example shows that a discrete-time steering control cannot always be obtained by discretizing a continuous-time steering control; the steering control for the discrete-time system must be obtained directly from the discrete-time model.     

线性矩阵方程异类约束最小二乘解的迭代算法

多矩阵变量线性矩阵方程(LME)约束解的计算问题在参数识别、结构设计、振动理论、自动控制理论等领域都有广泛应用。本文借鉴求线性矩阵方程(LME)同类约束最小二乘解的迭代算法,通过构造等价的线性矩阵方程组,建立了求多矩阵变量LME的一种异类约束最小二乘解的迭代算法,并证明了该算法的收敛性。在不考虑舍入误差的情况下,利用该算法不仅可在有限步计算后得到LME的一组异类约束最小二乘解,而且选取特殊初始矩阵时,可求得LME的极小范数异类约束最小二乘解。另外,还可求得指定矩阵在该LME的异类约束最小二乘解集合中的最佳逼近解。算例表明,该算法是有效的。     

Optimal experiment design for linear systems with input-output constraints

The problem of optimal experiment design for parameter estimation in linear dynamic systems is studied. Results relating to both constrained input and output variances are established. For the case of constrained input variance, it is shown that a D-optimal experiment exists in which the system input is generated externally provided the system and noise transfer functions have no common parameters. For the case of constrained output variance, it is shown that an experiment in which the system input is generated by a combination of a minimum variance control law together with an external set point perturbation is D-optimal for certain classes of systems. Other related results are also presented which illustrate the role of feedback in optimal experiment design.     

基于遗传算法的结晶器液位约束广义预测控制

针对实际连铸过程中结晶器液位控制须满足多种约束的问题,将一种基于遗传算法的有约束广义预测控制方法（ＧＣＧＰＣ）应用于结晶器液位控制．首先基于机理模型构造了有约束结晶器液位广义预测控制器;然后以遗传算法处理带约束的非线性优化问题,并以此作为滚动优化策略,求得最优控制律．仿真结果表明,在有效处理了约束的基础上,基于遗传算法的有约束广义预测控制效果优于ＰＩＤ 控制以及无约束广义预测控制．     

Simultaneous pole assignment in linear periodic systems byconstrained structure feedback

The authors present methods for pole assignment by feedback with constrained structure in linear periodic systems using generalized sampled-data hold functions (GSHF). Constrained structure is taken to mean that the input of each channel is restricted to depend only on the measurements of some specific output channels. The basic idea of GSHF control is to use sample and hold, but to consider the hold function as a design parameter. Four strategies are proposed for closing a control loop using GSHF. The key to the results obtained is that, when GSHF control with constrained structure is applied to a periodic system, a discrete-time time-invariant, decentralized system is obtained for which control design methods are available     

Minimum variance performance map for constrained model predictive control

A minimum variance performance map is introduced for constrained linear model predictive control (MPC). The minimum variance performance map provides a demonstration of the effect of constraints in an MPC on the best achievable controller performance. The constrained minimum variance controller is formulated for the MPC system to be monitored. Using multi-parametric quadratic programming (mp-QP), the linear, piecewise control law is obtained for the constrained minimum variance controller. The linear, piecewise control law is used with a Kalman filter to obtain the minimum output variance in each region of the state space partition. The minimum variance performance map is demonstrated on a second order process with a constraint on the input amplitude.