Design of control system for autonomous airship and experiment

飞艇是一种独特的交通工具，可以实现安全和长时间的飞行和位置保持。最近，对无人驾驶飞艇的兴趣越来越大。许多有趣的项目正在进行中，例如平流层平台项目，其中平流层飞艇被用作代替卫星进行高速无线通信的移动的低成本平台。位姿控制是飞艇控制技术的重要组成部分，本文研究了欠驱动飞艇的平面位姿控制问题，该飞艇是一个独立输入小于被控自由度的非完整系统。针对欠驱动飞艇动力学存在有界不确定性的情况，研究了飞艇的鲁棒全局镇定问题。利用平滑的时变坐标变换，将飞艇的控制问题转化为线性系统的控制问题。该变换不依赖于系统的初始状态，并且是非奇异的。获得以下优点。首先，处理的情况下，动态是已知的，并提出了一种新的控制器，以保证指数稳定的系统的任何初始状态。基于著名的线性控制理论的设计方法是简单和直接的。其次，研究了参数未知但有界的不确定飞艇的鲁棒镇定问题。新的问题归结为著名的二次镇定问题的不确定线性系统。该设计方法简单，涉及到一定的代数Riccati方程。最后，实验结果表明所提出的控制系统的有效性。

Airship is a unique vehicle which enables safe and long-duration flight and station keeping. Recently, the interest to unmanned airships has been increasing. Many interesting projects are in progress such as Stratospheric Platform Project, in which the stratospheric airship is utilized as a mobile and low-cost platform for high-speed wireless communication instead of satellites. The position and attitude control is one of the most important component technologies.This study deals with the problem of controlling both the planar position and orientation of an under-actuated airship, which is a nonholonomic system with fewer independent inputs than degree of freedom to be controlled. A robust global stabilization problem is considered for the case where the dynamics of the underactuated airship are subjected to bounded uncertainties. A smooth and time-varying coordinate transformation is utilized to reduce the problem of the airship to that of a linear system. The transformation is independent of the initial state of the system and is nonsingular. The following advantages are obtained. First, the case is dealt with where the dynamics are known and presents a new controller to guarantee exponential stability of the system for any initial states. The design method based on the well-known linear control theory is simple and straightforward. Second, the robust stabilization problem is considered for the uncertain airship with unknown but bounded parameters. The new problem is reduced to the well-known quadric stabilization problem for an uncertain linear system. The design method is simple, and it involves a certain algebraic Riccati equation. Finally, experimental results show the effectiveness of the proposed control system.