發射載具的設計與入軌

Abstract

欲將衛星發射進入軌道，火箭是目前最常被使用的載具，利用持續的推力將自身及酬載一同推入高空，並以多節的型式持續加速以節省燃料。一般來說，火箭以垂直或接近垂直的角度發射，在大氣層中利用重力轉彎減少空氣阻力，以免載具受到側向力矩損壞，脫離大氣層後，在適當的時間與位置進行轉向，最後控制酬載在軌道上加速，並在預期的目標軌道上以正確的飛行方向與速度入軌。本文由設計載具以及時間參數開始，之後控制轉向與姿態，而最後在入軌加速階段，更以高度回授控制，讓軌道高度符合要求。由於火箭升空時，大部分的受力，包括氣動力、重力皆不是線性，除了需要預測軌跡以外，還需要在多次的模擬後進行改進。本文在不同的軌道要求下，利用一些控制器，進行整體設計並加入誤差，而在模擬結果中，使用的計算方式與控制法則能達到入軌的要求。

A rocket is the most frequently used vehicle to launch a payload into orbit for taking advantage of its continuous thrust to lift itself and the payload into the high altitude and of the multi-stage mode of sustained acceleration to economize the use of propellant. General speaking, the launch angle of the rocket is vertical or near vertical and gravity turn is used to the reduction of air resistance for avoiding the vehicle from damage of lateral torque in the atmosphere; and further, it can be steered into different directions in proper time and position after leaving the atmosphere; finally, the payload can be controlled to accelerate and enter the orbit with accurate directions and speed of flight in the expected target orbit. This thesis starts on design of rocket and time parameter and then the control of steering and attitude; eventually it makes use of altitude feedback control to meet the requirement of orbit altitude in the final acceleration stage of entering orbit. Because the rocket is forced a lot while launching, including the nonlinear force of aerodynamics and gravity, it not only requires the anticipation of trajectories but also many times of simulation for improvement. This thesis researches on the design with the consideration of errors for meeting different requirements of orbits and results of the simulation successfully achieve the goal of entering orbit by the use of the controller and calculation methods in different cases.