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This paper presents a navigation method for a mobile robot in urban environments. The navigation method employs a so-called Polar Traversability Index (PTI) to evaluate terrain traversal property along a specific direction and guide the robot's motion. In the navigation system, a 2-D Laser Rangefinder (LRF) is used to produce terrain maps in various(More)
  • Wen-Fang Xie
  • 2007
In this paper, a novel sliding-mode observer based adaptive controller is developed for the servo actuators with friction. The LuGre dynamic friction model is adopted for adaptive friction compensation. A sliding-mode observer is proposed to estimate the internal friction state of LuGre model. Based on the estimated friction state, adaptation laws are(More)
In this paper, an on-line identification algorithm is proposed for nonlinear systems identification via dynamic neural networks with different time-scales including both fast and slow phenomenon. The main contribution of the paper is that the Lyapunov function and singularly perturbed techniques are used to develop the on-line update laws for both dynamic(More)
— Smart actuators such as magnetorestrictive actuators, shape memory alloy (SMA) actuators, and piezoceramic actuators exhibit different hysteresis loops. In this paper, a generalized Prandtl-Ishlinskii model is utilized for modeling and compensation of hysteresis nonlinearities in smart actuators. In the formulated model, a generalized play operator(More)
In this paper, a new genetic algorithm (GA) is developed to optimize the architecture of a recurrent artificial neural network (RANN) with multiple hidden layers. A new direct matrix mapping encoding (DMME) method is proposed to efficiently and effectively represent the architecture of a neural network. A modified back-propagation (BP) algorithm is utilized(More)