In this article, the problem of H∞ codesign for nonlinear control systems with unmatched uncertainties and adjustable parameters is investigated. The main purpose is to solve the adjustable parameters and H∞ controller simultaneously so that better robust control performance can be achieved. By introducing a bounded function and defining a special cost function, the problem of solving the Hamilton-Jacobi-Isaacs equation is transformed into an optimization problem with nonlinear inequality constraints. Based on the sum of squares technique, a novel policy iteration algorithm is proposed to solve the problem of the H∞ codesign. Moreover, one modified algorithm for optimizing the robust performance index is given. The convergence and the performance improvement of new iteration policy algorithms are proved. Simulation results are presented to demonstrate the effectiveness of the proposed algorithms.

中文翻译：

---

基于策略迭代法的不确定非线性控制系统的H∞协同设计。

本文研究了具有不确定性和参数可调的非线性控制系统的H∞符号问题。主要目的是同时解决可调参数和H∞控制器，以便获得更好的鲁棒控制性能。通过引入有界函数并定义特殊的成本函数，将求解Hamilton-Jacobi-Isaacs方程的问题转化为具有非线性不等式约束的优化问题。基于平方和技术，提出了一种新的策略迭代算法来解决H∞码符号的问题。此外，给出了一种用于优化鲁棒性能指标的改进算法。证明了新迭代策略算法的收敛性和性能改进。