SIA OpenIR  > 空间自动化技术研究室
漂浮基空间机械臂耦合动力学与基体无扰研究
其他题名Research on Coupled Dynamics of a Space-based Manipulator System and Zero-disturbance of Its Floating Base
陈正仓1,2
导师周维佳
分类号TP241
关键词空间机械臂 容许运动空间 动力学耦合 解耦
索取号TP241/C49/2017
页数153页
学位专业机械电子工程
学位名称博士
2017-12-04
学位授予单位中国科学院沈阳自动化研究所
学位授予地点沈阳
作者部门空间自动化技术研究室
摘要本文围绕漂浮基空间机械臂系统动力学建模理论新方法、工作空间分布特点及其组成、机械臂与基体之间的动力学耦合原因、性质及其解耦方法、考虑解耦要求的路径规划与避障和相关仿真实验等方面,依次开展了以下几个方面的研究工作:(1)漂浮基空间机器人自上世纪七、八十年代开始逐渐进入人们视野,目前,以位姿可控的卫星或航天器上搭载单个或多个机械臂形式存在居多。机械臂在执行任务过程中,如何减少对基体位置、姿态的影响是本文研究的核心问题。因此,一方面,对前人关于漂浮基空间机械臂建模、动力学耦合分析等方面的工作进行调研,并总结其中存在的不足之处,另一方面,搭建文章研究框架,为后续的研究工作提供路线依据。(2)数学模型是一个物理系统所要面对的实际问题与数学工具之间的必不可少的沟通桥梁。文中分别从坐标系选择、模型描述方法、非完整性分析等角度对系统进行了梳理;提出了容许运动空间的概念,并以此为依据,引出了一种针对漂浮基空间机械臂系统的建模新方法。(3)工作空间是反映系统工作能力的一个重要特征,工作空间分析也是机器人执行任务过程中必不可少的一环。与固定基机械臂系统相比,漂浮基系统工作空间分布更加复杂,这是由系统的非完整性所导致的。当系统进行逆向运动学、动力学控制时,系统的动力学奇异性也会给整个过程带来困难。因此,通过工作空间分析和动力学奇异分析过程,寻找出一个可以成功规避动力学奇异现象的路径无关工作空间是本文的又一目的。这也是耦合动力学解耦过程的一个必要前提。(4)动力学耦合机理与解耦方法是本文研究的重中之重。为了显式的描述这一问题,提出了动力学耦合度的概念,并介绍了耦合度的度量方法。用耦合度椭球这个概念几何体还可以从感官上给出一种定性的耦合度大小的表达。通过对系统的约束和任务分类,运用响应零空间方法,将动力学解耦问题转化为非奇异线性方程的求解问题。然后,结合路径无关工作空间分析结果和虚拟机械臂方法,验证路径无关工作空间中运动分解速度控制方法成功避免动力学奇异问题的可行性。(5)动力学解耦的效果取决于系统的任务约束种类和个数,换句话说,有时任务约束可能存在矛盾,并不能顾此即彼,动力学解耦过程可能存在无解的情形。所以,文中提出了将动力学解耦作为优化目标之一的路径规划方法来解决这一问题。其中,从关节空间中进行路径规划避免了系统遇到非奇异性问题的影响;量子遗传算法的应用体现出其收敛速度快、搜索能力强的优点;Pareto最优解为相互矛盾优化目标提供了解决方案;多约束避障问题的路径规划为解决实际问题提供了重要的解决思路。(6)运用SpaceDyn仿真平台,进行相关仿真试验。为了说明机械臂与基体之间存在动力学耦合现象,进行仿真实验一:正向运动学仿真实验,观察基体位姿所受影响,以及末端位置变化曲线;为了说明动力学解耦方法的有效性,进行仿真实验二:动力学解耦过程仿真,观察基体位姿响应。
其他摘要This text will develops based on the new modeling method of SBMSs, characteristics and composition of workspace distribution, dynamic coupling reason, property and decoupling method, path-planning and obstacle avoidance, relavant simulation tests and so on. (1)Since the 1970s and 80s, space-based robots gradually come into people’s mind, and they exist mostly in the form that one or more manipulator is installed on a satellite or spaceflight with a controllable attitude or position. The core issue of this paper is that how to reduce the disturbance to the floating base during the process of a robotic arm performing tasks. So, on the one hand, investigate the previous work on modeling and coupled dynamics of SBMSs; on the other hand, set up research framework and provide a route for the follow-up research. (2) Mathematical model is an essential communication bridge between physical problems faced by a physical system and mathematical tools. In this paper, from the view of coordinate system selection, model description method and nonholonomic analysis, the context is sort out. Then provide a concept called allowable motion space, and introduce a new modeling method which is specially aiming at the SBMSs. (3) Workspace is an important index to reflect the performance of a system. And workspace analysis is also an essential part during task execution process. Compared to a fixed base system, workspace distribution of space-based system is much more complex, which is caused by the nonholonomics. When inverse kinematic and dynamic control are conducted, dynamic singularities will be a thorny problem. So, by means of workspace analysis and dynamic singular analysis, another purpose is to find a path independent workspace that can successfully avoid dynamic singularities. This is a necessary prerequisite for decoupled dynamics. (4) The dynamic coupling mechanism and decoupling memthod are the most important. To describe the problem explicitly, propose the concept of dynamic coupling degree and introduce its measurement method. A kind of geometry called coupling degree ellipsoid can describe qualitatively the coupling degree. Then, classifing constraints and tasks of the system, and using Null-reaction space method, decoupled dynamic problem is transformed into a solution problem of nonsingular linear eqations. Next, with analysis results of path independent workspace and the Virtual Manipulator concept, the feasible of motion decomposition speed control method in path independent workspace is proved to avoid the feasibility of dynamic singular problem. (5) The effect of dynamic decoupling depends on the type and the number of constraints. In the other word, sometimes, constraints are contradictory to one another, just because of this, there may be no solution in the dynamic decoupling process. So, a method of path planning, one of its optimization objectives is defined as dynamic decoupling, is proposed to solve this problem. Path planning in joint space can successfully avoid nonsingular problems. The application of quantum genetic algorithm shows its advantages such as fast convergence and strong searching ability. The Pareto optimal solution provides a solution for conflicting optimization goals. Path planning of multi-constrain avoidance problem provides an important idea to solve practicle issues. (6) SpaceDyn simulation platform is used to carry out related simulation experiments. In order to explain the dynamic coupling phenomenon between a manipulator and a floating base, the first simulation test is carried out: that is forward kinematic simulation, abserving pose change of the base and the end-effector. In order to illustrate the effectiveness of the dynamic decoupling method, the second simulation is carried out: that is dynamic decoupling process simulation.
语种中文
产权排序1
文献类型学位论文
条目标识符http://ir.sia.cn/handle/173321/21271
专题空间自动化技术研究室
作者单位1.中国科学院沈阳自动化研究所
2.中国科学院大学
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GB/T 7714
陈正仓. 漂浮基空间机械臂耦合动力学与基体无扰研究[D]. 沈阳. 中国科学院沈阳自动化研究所,2017.
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