Jin-Young Jeon

Compensation for servo drift in industrial robots

A control technique is proposed for compensating for servo drift due to a wide range of temperature fluctuation without any overshoot of the robot end-effector. The effect of servo drift on the position of the end-effector is estimated, and the compensation for servo drift is then based on the estimation. Thus, an integral action need not compensate for the whole servo drift but rather to compensate the difference between the servo drift and its estimation. Since this difference is very small compared with the magnitude of the drift, an integral with a small limiter, which prevents the integral wind-up, is enough to reduce the effect of servo drift on the end-effector position to null. An application of the proposed control to an industrial robot is illustrated, and the result is compared with that for a PD (proportional-derivative) control.<<ETX>>

A Study on Acoustic Radiation Reduction of a Vibrating Panel by Using Particle Swarm Optimization Algorithm

In this paper, the author proposes a new method for acoustic radiation optimum design to minimize noise from a vibrating panel-like structure using a collaborative population-based search method called the particle swarm optimization algorithm(PSOA). The PSOA is a parallel evolutionary computation technique initially developed by Kennedy and Eberhart. The acoustic radiation optimization method based on the PSOA consists of two processes. In the first process, the acoustic radiation analysis by an integrated p-version FEM/BEM, which was developed by using MATLAB, is performed to evaluate the exterior acoustic radiation field of the panel. The second process is to search the optimum design variables: 1) Shape of Bezier curves and 2) Shape and position of ribs, to minimize noise from the panel using the PSOA. The optimization method based on the PSOA is compared to that based on the steady state genetic algorithm(SSGA) in order to verify the effectiveness and validity of the optimal solution by PSOA. Finally, it is shown that the optimal designs of the panel obtained by using the PSOA can achieve effective reductions in radiated sound power.