冗余自由度机器人的运动学控制
文献类型：学位论文
| 作者 | 黄磊光 |
| 学位类别 | 工学博士 |
| 答辩日期 | 1997-07-01 |
| 授予单位 | 中国科学院自动化研究所 |
| 授予地点 | 中国科学院自动化研究所 |
| 导师 | 李耀通 ; 谭民 |
| 关键词 | 冗余自由度机器人 运动学 局域优化法 阻尼伪逆 可重复性 kinematically redundant manipulators kinematics local optimization scheme damped pseudoinverse repeatability |
| 其他题名 | Kinematic Control of Redundant Manipulators |
| 学位专业 | 控制理论与控制工程 |
| 中文摘要 | 本文较为深入地研究了冗余自由度机器人运动学控制中的几个关键问题，得 出了一些具有实际应用前景的方法。 首先，对一个简单的冗余自由度机器人作彻底的运动学控制剖析。通过位移 级的运动学方程，分析一般平面机器人的工作空间，指出并纠正了一篇经典文献 中有关工作空间举例的一个失误。对梯度投影法应用的四个典型方面即应付关节 越限、碰撞、驱动能量极小、奇异性作了分析。指出关节奇异现象所带来的后果， 简要分析避免奇异的途径。提出梯度投影法的改进形式和相应的算法，这种新方 案能以关节奇异程度为依据进行次级性能指标的动态优化，并使关节速度的变化 趋于平稳。可重复性问题的存在则通过举例加以说明。 其次，以关节奇异研究为背景，解决了关节奇异对策与性能指标优化之间存 在的矛盾。回顾了阻尼最小方差准则下推导出阻尼伪逆的过程，然后给出基于阻 尼伪逆的控制器设计方案，使得阻尼可以根据实际需要自动地施加和调整强度， 从而既能达到近奇异关节配置附近抑制关节速度的目的，又尽可能减小正常关节 配置下的末端路径跟踪误差。进一步的扩展阻尼伪逆法则是～个集成的解决方 案，它在理论上的优点是能做到在动态阻尼和动态性能优化之间进行自动切换； 并行算法的设计又使它具备了在实用上的优点，就是该方案的实施完全有可能达 到实时控制级别。仿真例子将该方案与相关传统方案的性能做了比较研究。 再次，针对冗余自由度机器人的一些不可重复伪逆控制的缺点和已有的几种 可重复性控制方案的特征，提出实施可重复性控制的一种统一框架。接着通过算 法奇异的考虑，改进了这一实施方案，使它能够避免算法奇异对基本任务执行所 造成的误差，而且运动过程中关节速度的过渡将平稳化，次级任务的跟踪误差也 可望降低。同时，可重复性得到最大限度的保证。这种框架可以方便地应用到非 冗余自由度机器人的控制场合，有利于提高它完成主要操作任务的可靠程度。在 用计算机仿真验证这种方案的有效性之后，进一步探讨了它在算法改进和应付运 动学奇异上的初步设想。 最后，对冗余自由度机器人运动学控制数值仿真的一些主要方面，如建模、 离散化、算法与编程、结果与分析等，作了总结。 |
| 英文摘要 | The thesis investigates extensively several key problems in the kinematic control of redundant robotic manipulators. The main results of this thesis are as follows: First, a three-degree-of-freedom planar arm, as a specific case of kinematically redundant manipulators, is studied thoroughly. Workspace is analyzed for general planar arms, then an omission, in a frequently quoted paper, on the working range of a planar manipulator is identified and improved. Primary applications of the gradient projection method are exemplified, among which are joint limit avoidance, collision avoidance, joint kinetic energy minimization, and singularity escaping. Effects of singular joint configurations on Cartesian task execution are examined and ways to avoid them are discussed. An improvement of the gradient projection scheme and relevant algorithm are proposed, such that a secondary performance index is optimized dynamically according to the manipulator's distance away from singularity, and joint velocities are expected to change more smoothly. Repeatability of kinematic control of redundant robots is illustrated with an example. Second, based on studies on kinematic singularity, the contradiction between singularity escaping and performance optimization is resolved. The damped pseudoinverse solution is deduced in the sense of damped least squares, then a new damped pseudoinverse controller is presented. By implementation of this controller damping can be applied automatically according to actual joint situations, thus high joint speed near singularity is restrained and tracking error of end-effect or path is minimized for regular joint configurations. The extended damped pseudoinverse control scheme is an integrated solution, whose theoretical advantage is automatic switching between dynamic damping and dynamic optimization of secondary performance criterion. A computationaUy efficient parallel algorithm strengthens the scheme in that it is expected to be implemented in real-time robotic systems. Simulations show the advantages of the scheme to conventional relative ones. Seeing the shortcomings of unrepeatable pseudoinverse control methods for manipulators with redundant joints, and the characteristics of several available repeatable ones, a general framework for repeatable control of redundant mechanisms is provided and redundancy is resolved in the framework. By taking algorithmic singularity into consideration, the scheme is improved in such a way that tracking error for primary task is minimized and repeatability is guaranteed if no singularity is encountered. Via our choice of dynamic damping, joint speed is expected to change smoothly and tracking error of secondary goals is also hoped for to be minimized. The whole scheme can be applied readily to the case of non-redundant manipulators, to ensure the execution of the most important tasks to the maximum extent. Further discussions on algorithm enhancement an |
| 语种 | 中文 |
| 其他标识符 | 399 |
| 源URL | [http://ir.ia.ac.cn/handle/173211/5674]  |
| 专题 | 毕业生_博士学位论文 |
| 推荐引用方式 GB/T 7714 | 黄磊光. 冗余自由度机器人的运动学控制[D]. 中国科学院自动化研究所. 中国科学院自动化研究所. 1997. |
入库方式： OAI收割
来源：自动化研究所
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