For strict-feedback nonlinear systems (SFNSs) with unknown control direction, this paper synthesizes an asymptotic tracking controller by a combination of the dynamic surface control (DSC) technique, the Nussbaum gain technique (NGT) and fuzzy logic systems (FLSs). The SFNSs under study feature unknown nonlinear uncertainties and external disturbances. By utilizing the DSC technique with nonlinear filters, the issue of ‘differential explosion’ is obviated, in which the adaptive laws are constructed to conquer the effect of unknown functions. The FLSs are exploited to cope with uncertainties without any prior conditions of the ideal weight vectors and the approximation errors. In addition, by introducing the NGT, the unknown control direction problem is solved. Compared with the existing results, the proposed design procedure is able to simultaneously overcome the ‘differential explosion’ and the unknown control direction problems, and asymptotic tracking is accomplished. At the end, a second-order numerical system and a more realistic Norrbin nonlinear mathematical model are applied to confirm the feasibility of the design procedure.

针对控制方向未知的严格反馈非线性系统（SFNSs），本文将动态表面控制（DSC）技术、Nussbaum增益技术（NGT）和模糊逻辑系统（FLSs）相结合，合成了一种渐近跟踪控制器。研究中的 SFNS 具有未知的非线性不确定性和外部干扰。通过利用带有非线性滤波器的 DSC 技术，避免了“微分爆炸”问题，其中构建了自适应定律来克服未知函数的影响。利用 FLS 来应对不确定性，而无需任何理想权重向量和近似误差的先验条件。此外，通过引入NGT，解决了未知控制方向问题。与现有结果相比，所提出的设计程序能够同时克服“差分爆炸”和未知控制方向问题，并实现了渐近跟踪。最后，应用二阶数值系统和更现实的 Norrbin 非线性数学模型来确认设计程序的可行性。