Prerequisites to the successful application of the H∞ control design technique to the marine dynamic positioning (DP) control problem are a realistic nominal model, relative bounds on modelling uncertainty, a set of frequency-dependent weighting functions to translate the control design specification into a control solution and a performance index to quantify the robustness. The authors propose procedures and algorithms to achieve these objectives. The H∞ robust control design technique is then used to calculate a robust controller which has superior properties to the conventional DP systems. The trade-off between track keeping and station keeping is undertaken via appropriate weighting functions and a two-degree-of-freedom control structure is employed. The technique proposed shows that effective wave filtering can be obtained with guaranteed stability robustness. The advantage of the proposed control design technique is demonstrated using ship nonlinear simulations.

H∞ robust control design for dynamic ship positioning : Special section on marine control

This study aimed to determine whether the computer can be used to control threephase induction motor with the help of Centronic interfaces and peripherals that run with the program. These peripheral circuits consist of electronic components (circuit relay driver, relay and contactor magnet DC) which receives digital pulse from the interface that originated from a computer and forward it to drive the relay pulse, peripheral circuits are working with the help of a computer program that utilizes output data from the card printer (LPT1) to communicate with peripherals that are made.

Control system engineering design in three phase motor

The paper studies the control law of flapped fin service system in the joint control system of the main/flapped fin stabilizer. An LQ inverse design based on the pole placement method is used by means of the state feedback inverse design. The H/sup /spl infin// control theory is also adopted to design the flapped fin service system. The simulation results are given and contrasted with the result designed by the classical control theory. The advantages of the modern control theory are validated.

Deng Zhihong

Papers

The study of flapped fin service system of main/flapped fin stabilizer