Application of neural network to rock slope stability assessments

It is known that rock masses are inhomogeneous, discontinuous media composed of rock material and naturally occurring discontinuities such as joints, fractures and bedding planes. These features make any analysis very difficult using simple theoretical solutions. Generally speaking, back analysis technique can be used to capture some implicit parameters for geotechnical problems. In order to perform back analyses, the procedure of trial and error is generally required. However, it would be time-consuming. This study aims at applying a neural network to do the back analysis for rock slope failures. The neural network tool will be trained by using the solutions of finite element upper and lower bound limit analysis methods. Therefore, the uncertain parameter can be obtained, particularly for rock mass disturbance.<br /

Hybrid incremental modeling based on least squares and fuzzy K-NN for monitoring tool wear in turning processes

There is now an emerging need for an efficient modeling strategy to develop a new generation of monitoring systems. One method of approaching the modeling of complex processes is to obtain a global model. It should be able to capture the basic or general behavior of the system, by means of a linear or quadratic regression, and then superimpose a local model on it that can capture the localized nonlinearities of the system. In this paper, a novel method based on a hybrid incremental modeling approach is designed and applied for tool wear detection in turning processes. It involves a two-step iterative process that combines a global model with a local model to take advantage of their underlying, complementary capacities. Thus, the first step constructs a global model using a least squares regression. A local model using the fuzzy k-nearest-neighbors smoothing algorithm is obtained in the second step. A comparative study then demonstrates that the hybrid incremental model provides better error-based performance indices for detecting tool wear than a transductive neurofuzzy model and an inductive neurofuzzy model

Intelligent sliding mode control in flexible structures

The first objective of this work is to develop an intelligent sliding mode controller for vibration control in flexible structures. The proposed control consists of two processes: system identification and sliding mode control. System identification is performed based on a neural fuzzy (NF) approximator. A novel extended gradient method and a modified least square estimate (LSE) algorithm are proposed for neuro-fuzzy system training. The training is performed in a hybrid approach: the nonlinear parameters in the NF approximator are updated using the extended gradient method while the linear parameters are optimized by the modified LSE. In system control, an enhanced sliding mode (ESM) control system is developed to promote the control effort for active vibration suppression especially in flexible structures. Based on experimental investigation, when the principle of the terminal attractor is used in the classical gradient descent algorithm or sliding mode control systems, it causes implementation problems because the initial condition should be nonzero. The proposed training techniques provide faster convergence while avoiding the associated implementation problems. The stability of the proposed training techniques is demonstrated by the Lyapunov analysis. The effectiveness of the developed techniques is verified experimentally with a flexible structure experimental setup. Test results show that the suggested hybrid training technique can effectively improve the convergence of the NF approximator; the ESM controller can efficiently perform vibration suppression in flexible structures and easy to implement. The commonly used global search method is genetic algorithm (GA). The problems in the classical GA are low convergence speed and lack of fast global search capability for complex search space. The second objective of this work is to develop a more efficient global training approach, called enhanced genetic algorithm (EGA) for system training and optimization applications. Two approaches are proposed: Firstly, a novel group-based branch crossover operator is suggested to thoroughly explore local space and speed up convergence. Secondly, an enhanced MPT (Makinen-Periaux-Toivanen) mutation operator is proposed to promote global search capability for complex search space. The effectiveness of the developed EGA is verified by simulations based on a series of benchmark test problems. Test results show that the branch crossover operator and enhanced MPT mutation operator can effectively improve the convergence speed and global search capability. The EGA technique outperforms other related GA methods with respect to global search efficiency and operation efficiency

A fuzzy neural network approximator with fast terminal sliding mode and its applications

This paper presents a new training method for fuzzy neural network (FNN) systems to approximate unknown nonlinear continuous functions. Fast terminal sliding mode combining the finite time convergent property of terminal attractor and exponential convergent property of linear system has faster convergence to the origin in finite time. The proposed training algorithm uses the principle ofthe fast terminal sliding mode into the conventional gradient descent learning algorithm. The Lyapunov stability analysis in this paper guarantees that the approximation is stable and converges to the optimal approximation function with improved speed instead of finite time convergence to unknown function. The proposed FNN approximator is then applied in the control of an unstable nonlinear system and the Duffing system. The simulation results demonstrate the effectiveness of the proposed method

A fuzzy neural network approximator with fast terminal sliding mode and its applications

This paper presents a new training method for fuzzy neural network (FNN) systems to approximate unknown nonlinear continuous functions. Fast terminal sliding mode combining the 3nite time convergent property of terminal attractor and exponential convergent property oflinear system has faster convergence to the origin in 3nite time. The proposed training algorithm uses the principle ofthe fast terminal sliding mode into the conventional gradient descent learning algorithm. The Lyapunov stability analysis in this paper guarantees that the approximation is stable and converges to the optimal approximation function with improved speed instead of3nite time convergence to unknown function. The proposed FNN approximator is then applied in the control ofan unstable nonlinear system and the Du5ng system. The simulation results demonstrate the effectiveness of the proposed method

A fuzzy neural network approximator with fast terminal sliding mode and its applications

This paper presents a new training method for fuzzy neural network (FNN) systems to approximate unknown nonlinear continuous functions. Fast terminal sliding mode combining the 3nite time convergent property of terminal attractor and exponential convergent property oflinear system has faster convergence to the origin in 3nite time. The proposed training algorithm uses the principle ofthe fast terminal sliding mode into the conventional gradient descent learning algorithm. The Lyapunov stability analysis in this paper guarantees that the approximation is stable and converges to the optimal approximation function with improved speed instead of3nite time convergence to unknown function. The proposed FNN approximator is then applied in the control ofan unstable nonlinear system and the Du5ng system. The simulation results demonstrate the effectiveness of the proposed method

A fuzzy neural network approximator with fast terminal sliding mode and its applications

This paper presents a new training method for fuzzy neural network (FNN) systems to approximate unknown nonlinear continuous functions. Fast terminal sliding mode combining the finite time convergent property of terminal attractor and exponential convergent property of linear system has faster convergence to the origin in finite time. The proposed training algorithm uses the principle ofthe fast terminal sliding mode into the conventional gradient descent learning algorithm. The Lyapunov stability analysis in this paper guarantees that the approximation is stable and converges to the optimal approximation function with improved speed instead of finite time convergence to unknown function. The proposed FNN approximator is then applied in the control of an unstable nonlinear system and the Duffing system. The simulation results demonstrate the effectiveness of the proposed method