Narrow Results

Each rapid prototyping (RP) process has its special and unique advantages and disadvantages. The chapter presents a state-of-the-art study of RP technologies and classifies broadly all the different types of rapid prototyping methods. Subsequently, the fundamental principles and technological limitations of different methods of RP will be closely examined. Comparison of the present and ultimate performance of the rapid prototyping processes will be made so as to highlight the possibility of future improvements for a new generation of RP system.

Based on the classical control theory, this paper proposes an adjustable speed motor control model with minimum ripple effect. This feasibility study was conducted and simulated in Matlab using three typical input signals: the unit step, unit speed and acceleration. The simulation results shown that, the minimum ripple controller could ensure the speed of the electromagnetic speed control motor followed the expected speed in the shortest sampling cycle, to achieve the steady-state error of the system to zero. However, it only follows a particular input signal and therefore when the input signals vary, the controllers need to be calibrated separately to follow the signals, hence, with an electromagnetic adjustable speed motor, it is feasible to control a thin coal seam electrical traction shearer with minimum ripple effect.

In the current vessels is commonly used way of heaving line throwing outype, port type, rotary, centrifugal several, but every way heaving line is based on the power, speed is the core of speed strength of throwing project. The crew in the process of throwing by their own power to heaving line heads certain initial velocity. In this paper, through literature, survey, according to the theory of sports biomechanics, mechanics, sports anatomy for theory basis, combining the theory of track and field technique and related process of heaving line throwing discus throwing power points the swimmer is studied. Purpose is heaving line throwing theory; provide certain scientific basis for improving throwing distance.