Tetsuhiko Yamamoto

Vibration control of load for rotary crane system using neural network with GA-based training

A neuro-controller for vibration control of load in a rotary crane system is proposed involving the rotation about the vertical axis only. As in a nonholonomic system, the vibration control method using a static continuous state feedback cannot stabilize the load swing. It is necessary to design a time-varying feedback controller or a discontinuous feedback controller. We propose a simple three-layered neural network as a controller (NC) with genetic algorithm-based (GA-based) training in order to control load swing suppression for the rotary crane system. The NC is trained by a real-coded GA, which substantially simplifies the design of the controller. It appeared that a control scheme with performance comparable to conventional methods can be obtained by a relatively simple approach.

A switch controller design for the acrobot using neural network and genetic algorithm

This paper presents an intelligent control method for the Acrobot with applications of neural network (NN) and genetic algorithm (GA). A switch controller is proposed where a neurocontroller (NC) optimized by GA is used for the swing-up stage and a linear quadratic regulator (LQR) is applied to the balancing stage. In order to analyze the characteristics of the proposed control system, we investigate the performance of the controller with different swing-up timing constraints. Simulation results show that the method has advantages in that it can provide smooth control process and allow us to flexibly define the swing-up time in advance.

Neurocontroller with a genetic algorithm for nonholonomic systems: flying robot and four-wheel vehicle examples

This article considers intelligent control for a class of nonholonomic systems using a neurocontroller (NC) and a genetic algorithm (GA). First, we introduce the design of the NC with use of the GA, and then we apply the NC to control two typical examples of nonholonomic systems: a hopping robot in the flight phase and a four-wheel vehicle. In order to verify the effectiveness of the control system, the performance of the NC is investigated and also compared to that of the so-called direct gradient descent control (DGDC) approach, which is able to utilize a GA with the same examples in the comparison. Simulations show that the NC could achieve a competitive performance and control the nonholonomic systems effectively. Furthermore, the use of the NN and GA provide a straightforward solution for the problem without the need of the chained form conversion.

Particle Swarm Optimization of a Recurrent Neural Network Control for an Underactuated Rotary Crane with Particle Filter Based State Estimation

This paper addresses the control problem of an underactuated rotary crane system by using a recurrent neural network (RNN) and a particle filter (PF) based state estimation. The RNN is used as a state feedback controller which is designed by a constricted particle swarm optimization (PSO). As the study also considers the problem with assuming that the velocities of the system are not obtained, PF is utilized to estimate the latent states. Simulations show that the RNN could provide a superior evolutionary performance and less computational cost compared to a feed forward NN and that the PF is effective in estimating the unobserved states.

Solution searching for multivariable optimization problems by a momentum genetic algorithm

Genetic algorithms (GAs) have emerged as powerful solution searching mechanisms, especially for nonlinear and multivariable optimization problems. Generally, it is time-consuming for GAs to find the solutions, and sometimes they cannot find the global optima. In order to improve their search performance, we propose a fast GA algorithm called momentum GA, which employs momentum offspring (MOS) and constant range mutation (CRM). MOS, which generates offspring based on the best individuals of current and past generations, is considered to have the effect of fast searching for the optimum solutions. CRM is considered to have the ability to avoid the production of ineffective individuals and maintain the diversity of the population. In order to verify the performance of our proposed method, a comparison between momentum GA and the conventional mean will be implemented by utilizing optimization problems of two multivariable functions and neural network training problems with different activation functions. Simulations show that the proposed method has good performance regardless of the small values of the population size and generation number in the GA.

Online neuroadaptive control of a rotary crane system

This paper is concerned with the control of a rotary crane system which is perturbed by a strong and sudden disturbance. Since the payload of the crane system is affected strongly by inertia, it is hardly stabilized quickly, particularly when there exists disturbance. An adaptive adjustment of the controller against the disturbance is thus needed to maintain the desired performance. The problem becomes more challenging when using evolutionary algorithms based techniques as they are usually computationally demanding. In this study, an online control method using neural network (NN) and genetic algorithm (GA) is proposed where a state is predicted and then used as a new initial condition for GA to perform re-designing the controller. Simulations show that the method works effectively to regulate the perturbed system to the desired state.