Armature Structure Research of a Synchronous Induction Coil Launcher
Armature is very important for a synchronous induction coil launcher which can transform the electric energy to kinetic energy and push the load forward. The structure of the armature will influence the kinetic energy conversion efficiency directly. This paper analyzes the armature structure of a capacitor-driven synchronous induction coil launcher. Length and thickness of the armature are analyzed that how these parameters influence the maximum velocity and system efficiency of the launcher. Current filaments model is used to calculate the motion characteristics of a tubular linear induction motors, which is verified by an experiment and finite-element code. Genetic algorithm optimizer is used to calculate the best trigger times of the coils and the maximum velocity under the conditions of different length and thickness of the armature. It is shown that when the armature mass is fixed, length and thickness of the armature will greatly increase the velocity of the armature. The best length of the armature should be almost 2–2.5 times the length of the coil. The best thickness of the armature could be estimated by skin depth.
Armature Performance Comparison of an Induction Coil Launcher
This paper focused on the verification of the current filament method and the performance comparison of different armatures. Armature has as much influence on the performance of a coil launcher as any other major subsystem. The design of an armature is influenced by a large set of highly coupled parameters. The sleeve armature is a common choice for experiment and analysis of a coil launcher. The current filament method is widely used to analyze the sleeve armature. However, due to skin effect, the current distribution will be inconsistent, and excessive heating will be caused in the sleeve armature. How to use the current filament method accurately should be considered. Another good choice is the solenoid armature, which can make current and temperature distribution uniformly. To verify the current filament method and compare the performance between a sleeve armature and a solenoid armature, several kinds of projectiles were constructed and tested, including a sleeve projectile, a 24-turn copper-ring projectile, a 20-turn wire-ring projectile, and a 20-turn solenoid projectile. Then, 2-D finite-element simulations based on the experiments were taken to further study the problems. It is shown that in the sleeve armature (including multiturn ring armature) most of the induced current tend to distribute unevenly in the armature. Over concentration of the current will cause excessive heat and limit the material, structure, velocity, and efficiency of the sleeve armature. The sleeve armature must be divided into enough number of filaments; otherwise, the current filament method may be invalid. A solenoid armature can solve these problems by distributing the induced current evenly. However, fabrication of the solenoid armature becomes another difficulty. Further analysis of the current density in the solenoid armature shows that the skin effect will work in the wire of the solenoid, but it has little influence on the system performance. A detailed description of the experiments and simulations will be presented in this paper.
Research on Control and Planning of Soft-Wing UAV for Haze Removal
The existence of fog and haze has caused great pollution to the environment. The research of removing haze is a hot topic in recent years. In this paper, a special haze removal algorithm based on Soft- Wing UAVis proposed. In this algorithm, two track control strategies are designed based on the Soft-Wing UAV model transfer function. A SIMULINK platform based mathematical model of Soft-Wing UAV is built to testified effectiveness of the two track control strategies. An autonomous ergodic-planning algorithm with greedy strategy and foldback algorithm for Soft-Wing UAV is designed. Within the algorithm, the haze regional has been modelled, the cost matrix is constructed, and the planning and ergodic strategy is proposed. Finally, the experimental results validates the reliability of the algorithm in the application of haze removal with the proposed evaluation Index.