【作者】 王玉辉；

【导师】 戴炬；

【作者基本信息】 山东科技大学 ， 控制理论与控制工程， 2011， 博士

【摘要】 稳定平台是指能够使被稳定对象在外来干扰作用下相对惯性空间保持方位不变,或在指令力矩作用下能按给定规律相对惯性空间转动的装置。水面舰船在海上航行中,受风浪影响会产生摇摆现象。船载摄像机受舰艇摇摆的影响而不稳定,常使被摄像目标丢失,所以摄像机必须架设在稳定平台上,通过稳定平台的方位、俯仰和滚转等驱动系统补偿舰艇的摇摆运动,使摄像机始终保持水平状态。本课题正是基于此现状而提出的,课题来源于青岛理工大学与青岛市公安局签订的立项：奥帆赛海上安保指挥系统(编号GAYY2008001)。在此项目基础上开展研究。该稳定平台有许多方面需要深入研究,本文只对与测量、控制系统有关的各方面开展研究工作。论文的主要工作如下：1、分析比较了两轴和三轴稳定平台的运动学特征,选择带有滚转框架的三轴平台进行海上摄像机稳定平台的设计,根据该三轴稳定平台的结构特点,导出了平台运动学和动力学耦合方程；2、采用经典超前-滞后控制和变结构控制两种方法对稳定平台进行了校正。仿真结果表明变结构控制方法具有快速响应、对参数变化及外界干扰具有强鲁棒性。控制性能优于超前滞后控制方法；3、讨论了影响控制系统精度的各因素,并提出解决办法。特别是针对陀螺测量信号中存在的噪声,从陀螺仪实测动态输出数据样本序列入手,建立了时间序列模型。比较了Kalman滤波算法和Sage-Husa自适应滤波算法,得出Sage-Husa算法更适应于该平台,同时对Sage-Husa算法进行改进,提高了算法的效率；4、提出了以FPGA为核心的稳定平台控制系统实现方法,并得以成功应用,取得良好的效果。本论文主要创新点如下：1、分析了两轴稳定平台的原理性缺陷,指出两轴稳定系统仅能实现视轴的指向稳定,而对引起视轴旋转方向的扰动无法消除。如果要解决视轴的旋转问题,可行的办法就是建立三轴摄像稳定平台；2、从经典的Kalman滤波算法入手,依据滤波发散的判据,将Sage-Husa自适应滤波算法进行改进,减小了计算量从而提高了系统的实时性；3、提出了基于摩擦补偿的变结构控制方法对稳定平台进行校正。由于变结构控制可在动态过程中,随时根据系统的状态,有目的地不断变化,迫使系统沿预定的“滑动模态”的状态轨迹运动。而该点恰恰符合该稳定平台系统的实际应用背景；4、凭借FPGA高速优点,设计了以FPGA为主控制器的数字控制电路,可对目标的运动迅速做出响应,用尽可能短的时间来调整误差。更多还原

【Abstract】 The stabilized platform is an equipment which can keep its orientation under the external disturbance, or can run regularly according to a given torque relative to the inertia space.Since wave fluctuations can cause a moving ship swaying at sea, the camera mounted on ship may be unstable due to this swaying and often miss the targets. Hence, in order to obtaing high-quality image it requires the mounted platform maintains stable. This stabilization can be achieved through the azimuth, the pitching and the roll drive systems. Based on the above situation we have an issue to study. It comes from a project:Sea Security Command System on Olympic Sailing Competition (No. GAYY2008001), which is signed with Qingdao Technological University and Qingdao Municipal Public Security Bureau. All our researches are based on this project. There are many problems associated with the platform stabilization, here only the aspects of measurement and control system are stressed.The main researches of this thesis are as follows:(1) The kinematical features of the two and three axis stabilized platforms are analyzed and compared. Meanwhile, the designing idea of three-axis camera stabilized platform contained the roll framework is also realized. According to the structure characteristics of the three-axis stabilized platform, its corresponding kinematic and dynamic coupling equations are deduced; (2) The classic lead-lag control and the variable structure control (VSC) methods are adopted to correct the platform system. The comparative simulation results show that the VSC method possesses the virtue of fast response fast, strong robustness with respect to the parameter change and external disturbance. In addition, its control performance is superior to the lead-lag control method; (3) The factors of controling precision are analyzed and several methods are proposed to improve the precision. Especially, in view of the noise existed in the gyroscopes measurement signal, a time series model is developed on the dynamic output data sample series. To say it in detail, it follows from the comparison between the Kalman filter algorithm and Sage-Husa adaptive filter algorithm that the last one is more suitable for the stabilization problem. Furthermore, some improvements are done on the Sage-Husa algorithm which result in more running efficiency; (4) A control-system-design method based on FPGA is put forward, which leads to successful applications.The main innovation is showed as follows:(1) Principle defect of two-axis stabilized platform is analyzed, and points out that the two-axis stabilized system can only achieve the point of the shaft stability, and can’t eliminate the disturbance of view axis rotation direction. In order to solve the problem, three-axis camera stabilized platform should be set up; (2) Sage-Husa adaptive filter algorithm was improved started form classic Kalman filter according to the criterion of spread of filter, this improvement may reduce calculation and enhance real-time of the system; (3) The VSC method based on friction compensation is put forward and applied to the correction of stable platform. VSC can change trajectory according to the state of the system in dynamic process and forces system to follow a prescribed "sliding mode" state. And this point just fits application background of the system platform; (4) Digital control circuits is designed based on high-speed controller FPGA, and the device could make rapid response to the movement of target, and adjust error as quick as possible.更多还原