Wai Rong-Jong, Yang Zhi-Wei
Department of Electrical Engineering and Fuel Cell Center, Yuan Ze University, Chung-Li 32003, Taiwan, ROC.
IEEE Trans Syst Man Cybern B Cybern. 2008 Oct;38(5):1326-46. doi: 10.1109/TSMCB.2008.925749.
This paper focuses on the development of adaptive fuzzy neural network control (AFNNC), including indirect and direct frameworks for an n-link robot manipulator, to achieve high-precision position tracking. In general, it is difficult to adopt a model-based design to achieve this control objective due to the uncertainties in practical applications, such as friction forces, external disturbances, and parameter variations. In order to cope with this problem, an indirect AFNNC (IAFNNC) scheme and a direct AFNNC (DAFNNC) strategy are investigated without the requirement of prior system information. In these model-free control topologies, a continuous-time Takagi-Sugeno (T-S) dynamic fuzzy model with online learning ability is constructed to represent the system dynamics of an n-link robot manipulator. In the IAFNNC, an FNN estimator is designed to tune the nonlinear dynamic function vector in fuzzy local models, and then, the estimative vector is used to indirectly develop a stable IAFNNC law. In the DAFNNC, an FNN controller is directly designed to imitate a predetermined model-based stabilizing control law, and then, the stable control performance can be achieved by only using joint position information. All the IAFNNC and DAFNNC laws and the corresponding adaptive tuning algorithms for FNN weights are established in the sense of Lyapunov stability analyses to ensure the stable control performance. Numerical simulations and experimental results of a two-link robot manipulator actuated by dc servomotors are given to verify the effectiveness and robustness of the proposed methodologies. In addition, the superiority of the proposed control schemes is indicated in comparison with proportional-differential control, fuzzy-model-based control, T-S-type FNN control, and robust neural fuzzy network control systems.
本文聚焦于自适应模糊神经网络控制(AFNNC)的发展,包括针对n连杆机器人操纵器的间接和直接框架,以实现高精度位置跟踪。一般而言,由于实际应用中的不确定性,如摩擦力、外部干扰和参数变化,采用基于模型的设计来实现这一控制目标较为困难。为解决此问题,研究了一种间接AFNNC(IAFNNC)方案和一种直接AFNNC(DAFNNC)策略,无需先验系统信息。在这些无模型控制拓扑中,构建了具有在线学习能力的连续时间Takagi-Sugeno(T-S)动态模糊模型来表示n连杆机器人操纵器的系统动态。在IAFNNC中,设计了一个FNN估计器来调整模糊局部模型中的非线性动态函数向量,然后,利用估计向量间接制定稳定的IAFNNC律。在DAFNNC中,直接设计一个FNN控制器来模仿基于预定模型的稳定控制律,然后,仅通过使用关节位置信息即可实现稳定的控制性能。从Lyapunov稳定性分析的角度建立了所有IAFNNC和DAFNNC律以及FNN权重的相应自适应调整算法,以确保稳定的控制性能。给出了由直流伺服电机驱动的双连杆机器人操纵器的数值模拟和实验结果,以验证所提方法的有效性和鲁棒性。此外,与比例微分控制、基于模糊模型的控制、T-S型FNN控制和鲁棒神经模糊网络控制系统相比,表明了所提控制方案的优越性。