【正文】
where M is a continuous, radially unbounded, positive definite function. TheMPC value function V is defined as where is the value function for the optimal control problem (the optimal control problem defined where the horizon isshrank in its initial part by ). From (7) we can then write that for any t ≥ t0 Since is finite, we conclude that the function is bounded and then that ds is also bounded. Therefore is bounded and, since f is continuous and takes values on bounded sets of is also bounded. All the conditions to apply Barbalat’s lemma 2 are met, yielding that the trajec tory asymptotically converges to the origin. Note that this notion of stability does not necessarily include the Lyapunov stability property as is usual in other notions of stability。 SampledData Model Predictive Control for Nonlinear TimeVarying Systems: Stability and Robustness Summary. We describe here a sampleddata Model Predictive Control framework that uses continuoustime models but the sampling of the actual state of the plant as well as the p utation of the control laws, are carried out at discrete instants of time. This framework can address a very large class of systems, nonlinear, timevarying, and nonholonomic. As in many others sampleddata Model Predictive Control schemes, Barbalat’s lemma has an important role in the proof of nominal stability results. It is argued that the generalization of Barbalat’s lemma, described here, can have also a similar role in the proof of robust stab ility results, allowing also to address a very general class of nonlinear, timevarying, nonho lonomic systems, subject to disturbances. The possibility of the framework to acmodate discontinuous feedbacks is essential to achieve both nominal stability and robust stability for such general classes of systems. 1 Introduction Many Model Predictive Control (MPC) schemes described in the literature use continuoustime models and sample the state of the plant at discrete instants of time. See . [3, 7, 9, 13] and also [6]. There are many advantages in considering a continuoustime model for the plant. Neverthe less, any implementable MPC scheme can only measure the state and solve an optimization pro blem at discrete instants of time. In all the references cited above, Barbalat’s lemma, or a modification of it, is used as an impo rtant step to prove stability of the MPC schemes. (Barbalat’s lemma is a wellknown and Power ful tool to deduce asymptotic stability of nonlinear systems, especially timevarying systems, using Lyapunovlike approaches。 舉例來說,是利用間斷的反饋控制策略榜榜類型,可以說是由少數(shù)參數(shù)等,使問題的計算 tractable 。 注意,我們是不會考慮的離散模型或動態(tài)方程。 7 有限參數(shù)的控制功能 結(jié)果的穩(wěn)定性和魯棒穩(wěn)定性,證明了用最優(yōu)控制問題所在是控制職能,選定由一個非常一般設(shè)置(一套可衡量的職能) 。 框架下文所述是基于一個在 [ 9 ] ,延長至 timevarying 系統(tǒng)。我們得出 和 因此, ,因為 是連續(xù)的,我們得出 所有的條件,申請 barbalat 的引理 2 會見,高產(chǎn),該軌跡漸近收斂到原點。 5 名義的穩(wěn)定 穩(wěn)定性分析可以進(jìn)行顯示,如果設(shè)計參數(shù)方便的選定(即選定,以滿足某一個足夠穩(wěn)定條件下,例如見 [ 7 ] ) ,然后在某貨幣政策委員會的價值函數(shù) V 是表明要單調(diào)遞減。 不過,這是我們認(rèn)為,這種泛化的引理可能提供一個有用的工具來分析穩(wěn)定在其他穩(wěn)健的連續(xù)時間的貨幣政策委員會的做法, 如一個形容這里時變系統(tǒng)的。這表明,如果某些設(shè)計參數(shù)(目標(biāo)功能,碼頭設(shè)置等) ,方便的選定,則值函數(shù)是單調(diào)遞減。 (見 [ 8 ]為一項調(diào)查,這些工程)的本質(zhì)特征 這些框架,允許間斷只不過是采樣數(shù)據(jù)的特點 適當(dāng)使用一種積極的跨采樣時間,再加上一個適當(dāng)?shù)慕忉尳鉀Q一個間斷微分方程。 解決的概念,已被證明是成功的在處理與穩(wěn)定由間斷的意見為是一種通用類別的可控系統(tǒng)概念是 “ 采樣 反饋 ” 提出的解決辦法 [ 5 ] 。 一遇到的困難,在控制這 種系統(tǒng)是任何線性周圍的原產(chǎn)地是無法控制的,因此任何的線性控制方法是無用的,以解決這些問題。這些包括控制豪華的 TC ,該預(yù)測地平線總磷,運行成本和終端成本的職能升和 W , 輔助控制律 kaux ,和終端約束集 正是由此產(chǎn)生的軌跡是由 這里 和功能 于是 類似的采樣數(shù)據(jù)框架使用的連續(xù)時間模型和采樣國家的核電廠在離散 instants的時間通過了在 [ 2 , 6 , 7 , 8 , 13 ] 并正成為公認(rèn)的框架,連續(xù)時間的貨幣政策委員 會。那個軌跡,有時是標(biāo)注為 的,當(dāng)我們想作明確地依賴于初始時間,初始狀態(tài),和控制功能。 我們假設(shè)這個制度,以漸近的可控性對 ,并為所有 我們進(jìn)一步假設(shè)函數(shù) f是連續(xù)的和局部 Lipschitz方面的第二個論點。不過,某種形式的有限參數(shù)的控制功能需要 /可取的解決上線的優(yōu)化問題。但是,遇到的困難是, 預(yù)測的軌跡,只有剛好與由此產(chǎn)生的軌跡在特定的抽樣 instants 。然后,運用 barbalat的引理,吸引力該軌跡的名義模型可以建立 (. x(t) → 0 as t → ∞ ).這種穩(wěn)定的狀態(tài)可以推斷,一個很籠統(tǒng)的類非線性系統(tǒng):包括時變系統(tǒng)的,非完整系統(tǒng),系統(tǒng)允許間斷意見,等此外,如果值函數(shù)具有一定的連續(xù)性屬性,然后 Lyapunov穩(wěn)定性(即軌跡停留任意接近的起源提供了足夠的密切開始向原產(chǎn)地)也可以得到保障(見例如[11]) 。 在所有的提述,引用上述情況, barbalat的引理,或修改它,是用來作為一個重要步驟,以證明穩(wěn)定的 MPC的計劃。