【作者】 程佳；

【导师】 王宣银；

【作者基本信息】 浙江大学 ， 机械电子工程， 2008， 博士

【摘要】 舰船在航行过程中,由于受到风浪等环境条件的影响,会产生横摇、纵摇、艏摇和升沉等运动,并且各种装备通常与舰船固连在一起,这些运动将造成装备指向的改变。稳定跟踪平台用于隔离舰船的运动并实现高性能跟踪运动,具有重大战略意义。现有研究都是针对采用串联结构的小负载稳定跟踪平台进行,本文首次系统深入地研究并联型稳定跟踪平台,从原理、特性、优化和控制等方面进行,主要内容如下:第一章,在查阅国内外相关研究文献的基础上,综述了现有稳定跟踪平台的结构形式和应用现状,简要介绍了并联机构的特点及应用,总结了并联机构的构型、工作空间、性能指标、尺度优化和控制策略等方面的研究现状,阐述了本课题的相关研究背景及意义,提出主要研究工作。第二章,建立并联型稳定跟踪平台的运动学和动力学模型。首先介绍了并联型稳定跟踪系统的构成,设计出新型4TPS-1PS并联平台结构。建立了考虑电、机、气特性的稳定跟踪平台单支链模型。推导出并联型稳定跟踪控制指令求解公式,建立平台的运动学模型,提出一种实时解析正解和一种基于Newton-Raphson方法的数值正解方法。建立静基座平台动力学模型,分析了动、静基座平台动力学模型的相同点与不同点,得到动基座动力学模型,仿真分析了载体扰动对各缸作用力的影响。第三章,对并联型稳定跟踪平台的工作特性进行研究。对平台执行机构—伺服电动缸特有的气阻特性进行仿真分析,绘制伺服电动缸的速度-输出力特性曲线。阐述完全可达工作空间概念,采用完全可达转动工作空间评价4TPS-1PS并联平台的工作空间。利用几何方法分析平台的理论极限转角,并提出完全可达转动空间的快速求解方法,计算得到平台样机的完全可达转动工作空间。提出平台速度、输出力的快速求解方法。分析得出并联型稳定跟踪平台的工作空间具有范围大且对称的特点,其输出速度和广义力具有幅值大且随位姿变化小的优点。第四章,研究并联型稳定跟踪平台的性能指标和尺度优化。推导出加权全局条件数、平台装机功率等性能指标的表达式,分析了各性能指标与结构参数的关系。以并联型稳定跟踪平台装机功率作为直接优化目标,以其他性能指标为约束条件,采用遗传算法对平台进行优化,仿真表明,以此指标优化的平台结构可以较大幅度地降低装机功率,并且满足其他性能指标要求.第五章,对并联型稳定跟踪平台的控制策略进行研究。首先对准闭环PID控制进行了探讨分析;然后提出一种位姿大闭环控制策略,将平台作为一个整体,直接对平台的位姿进行闭环控制,不对单个缸进行位置闭环控制。利用滑模变结构理论设计位姿大闭环鲁棒控制器。仿真结果表明该控制策略基本消除了各缸动态性能不一致引起的耦合误差,实现了各缸间的精确协同。针对稳定跟踪的特点和需求,引入计算扰动力补偿改进控制策略。仿真结果表明该控制策略有效消除了载体扰动和外部干扰及动力学模型误差的影响,可获得较高的稳定隔离度和稳定跟踪控制精度,鲁棒性好。第六章,稳定跟踪控制实验研究。建立了并联型稳定跟踪平台实验装置,设计了控制系统的硬件和软件。利用并联六自由度电液伺服平台模拟舰船运动,在实验室内进行稳定跟踪控制实验。进行了平台的功能性实验,验证平台软硬件设计的正确性和合理性。应用第五章设计的控制策略进行跟踪、稳定及稳定跟踪控制实验研究,测试出平台的精度及性能,验证了控制策略的有效性。第七章,总结本论文的主要工作,阐述研究结论和创新点,对并联型稳定跟踪平台的后续研究作出了展望。更多还原

【Abstract】 In the process of navigation, ships will have the movement of rolling, pitching, heading, rising and falling because of the influences of storms or other environmental conditions. However, equipments are usually fixed firmly on ships. The movement will change the direction of equipments. Stabilization and tracking platform is used to isolate the ship movement and achieve high-performance tracking movement, which is of great strategic significance and illustrate a good prospect of application. The existing studies were aimed at the stabilization and tracking platform with series structure. In this paper, the stabilization and tracking platform with parallel structure was studied systematically for the first time. The study was carried out from the aspects of principles, features, optimization and control etc... The main contents are as follows:In chapter 1, on the basis of referring to domestic and international associated documents, structures and the current application situation of the existing stabilization and tracking platform were summarized, characteristics and application of parallel mechanism were briefly introduced, and the current research conditions of configuration, workspace, performance indices, dimensional optimization, control strategies and other aspects of parallel mechanism were summed up. The related study background and significance of the subject were expounded, and the main study work was proposed.In chapter 2, the kinematics and dynamics models of parallel stabilization and tracking platform were built. Firstly, the constitution of stabilization and tracking system with parallel platform was introduced, and the structure of a new 4TPS-1PS parallel platform was designed. The model of platform’s actuating link was built considering the characteristics of electricity, mechanism and gas. The control command formulas of stabilization and tracking were deduced. The kinematics model of the parallel platform was built, and a real-time analytic forward kinematics solution and numerical forward kinematics solution based on Newton-Raphson method were presented. The dynamics model of the parallel stabilization and tracking platform with static base plate was built. The similarities and differences between dynamics models of the platform with moving or static base plate were analyzed. Furthermore the dynamics model of the platform with moving base plate was built. The influences of ships’ disturbance on the cylinders’ forces were simulated and analyzed.In chapter 3, the operating characteristics of parallel stabilization and tracking platform were studied. The pneumatic resistance of the servo electric cylinder was simulated, and the speed-output force curve of the servo electric cylinder was plotted out. The concept of full reachable workspace was expounded, and the full reachable rotation workspace was used to evaluate the workspace of parallel 4TPS-1PS platform. The theoretical rotation limits of the parallel platform were analyzed by geometry method, and a rapid solution of full reachable rotation workspace was put forward. The full reachable rotation workspace of the parallel platform prototype was calculated and plotted out. Rapid solutions of the parallel platform’s speed and output force were put forward. It was concluded that the parallel stabilization and tracking platform’s workspace had the characteristics of large range and symmetry, and the output speed and generalized force had the merits of large amplitude and little change with the parallel platform’s pose.In chapter 4, performance indices and dimensional optimization of the parallel stabilization and tracking platform were studied. The expressions of weighted global condition number, installed power of parallel platform and other performance indices were deduced. The relations between performance indices and structure parameters were analyzed. The parallel stabilization and tracking platform was optimized by using Genetic algorithm (GA), and taking the installed power of the parallel platform as the direct optimized goal and the other performance indices as constraints. The simulation results showed that the installed power of the parallel platform with optimized structure parameters was greatly reduced and the requirements of other performance indices were met.In chapter 5, control strategies of the parallel stabilization and tracking platform were studied. Firstly, the PID control strategy with pose open loop was analyzed. Then a pose servo control strategy was presented, in which the platform was taken as a whole, and controlled directly with pose servo, while the cylinders were no longer controlled with position servo singly. The robust pose servo controller was designed by using the sliding mode variable structure control theory. The simulation results showed that the coupled errors caused by the inconsistencies of four cylinders’ dynamic performances were almost eliminated, and the precise coordination between four cylinders was realized. Addressing the characteristics and the need of stabilization and tracking, the calculating disturbance force compensation was introduced to improve the control strategy. The simulation results showed that the influences of ships’ disturbance, external disturbance and dynamic model errors were effectively eliminated, and high isolation degree and tracking precision were achieved by using this control strategy. Furthermore, the strategy was robust.In chapter 6, experimental studies of stabilization and tracking were carried out. The parallel stabilization and tracking platform experimental device was developed, and the hardware and the software of the control system were designed. The parallel six degree-of-freedom hydraulic servo platform was used to simulate the ship’s movement for doing the stabilization and tracking control experiments in the laboratory. Functional tests of the parallel platform were firstly carried out to validate the correctness and rationality of the hardware and software design. Based on this, the experimental studies of tracking, stabilization and stabilization and tracking control were made by using the control strategy designed in chapter 5. Meanwhile, the accuracies and performances of the parallel platform were tested and the effectiveness of the control strategy was verified.In chapter 7, the major work of the study was summarized, and the conclusions and innovations of the study were elaborated. And the future study of the parallel stabilization and tracking platform was also prospected.更多还原