Observer-Based Sampled-Data Model-Free Adaptive Control for Continuous-Time Nonlinear Nonaffine Systems With Input Rate Constraints
Observer-Based Sampled-Data Model-Free Adaptive Control for Continuous-Time Nonlinear Nonaffine Systems With Input Rate Constraints
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DOI：
10.1109/tsmc.2020.2982491
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发表时间：
2021-12-01
影响因子：
8.7
通讯作者：
Jin, Shangtai
中科院分区：
文献类型：
--
作者：
Hui, Yu;Chi, Ronghu;Jin, Shangtai
针对具有输入速率约束的连续时间非线性非仿射系统，提出了一种采样数据无模型自适应控制（SMFAC）策略。利用微分中值定理和积分中值定理这两个基本数学工具，首先提出了一种采样数据局部动态线性化方法，将连续时间非线性非仿射模型转化为采样数据非线性仿射I/O模型，其中包含一个与控制输入相仿射的线性参数项和一个非线性不确定项。在此基础上，我们提出了一种基于采样器的SMFAC（ObSMFAC）方案，包括一个采样数据参数估计器估计未知偏导数和一个采样数据观测器估计剩余的非线性不确定性，分别。值得注意的是，采样周期被明确纳入所提出的ObSMFAC，提高了控制性能，减少其对系统稳定性的负面影响。控制律中还考虑了对输入速率的约束，作为输入更新算法的过渡条件。利用压缩映射原理证明了所提出的ObSMFAC的收敛性。仿真研究验证了理论结果。
A sampled-data model-free adaptive control (SMFAC) strategy is proposed for continuous-time nonlinear nonaffine systems with input rate constraints. By using differential and integral mean value theorems as two basic mathematic tools, a sampled-data local dynamic linearization method is proposed at first to transform the continuous-time nonlinear nonaffine model into a sampled-data nonlinear affine I/O model, including a linear parametric term affined to the control input and a nonlinear uncertainty term. On this basis, we consequently propose an observer-based SMFAC (ObSMFAC) scheme, including a sampled-data parameter estimator to estimate the unknown partial derivatives and a sampled-data observer to estimate the residual nonlinear uncertainty, respectively. Note that the sampling period is incorporated explicitly in the proposed ObSMFAC which enhances the control performance by reducing its negative influence on the system stability. The constraint on the input rate is also considered in the control law as the transition condition of the input updating algorithms. The convergence of the proposed ObSMFAC is proved by using the contraction mapping principle. The simulation study demonstrates the theoretical results.