【作者】 姚玉峰；

【导师】 蔡鹤皋； 孙立宁；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2009， 博士

【摘要】 移动操作机是一种由移动平台及安装其上的机械臂组成的机器人系统,具备大范围移动及作业能力,在助老助残、灾难救援、排险排爆等领域具有广泛应用前景。运动规划是移动操作机需要解决的重要问题,但由于8自由度轮式移动操作机(8 Degree Wheeled Mobile Manipulator, 8D-WMM)结构特点带来的非完整冗余特性,其运动规划问题较传统的移动机器人和冗余度机器人更为复杂,且8D-WMM一般工作于多障碍复杂环境下,如何合理利用其冗余度提升障碍环境下的作业能力具有重要的研究意义。当前,国内外在轮式移动操作机的机构综合及面向避障性能的逆运动学优化方面缺乏系统性的研究,无法充分发挥该构型机器人在复杂环境下的灵活作业能力。为此,论文对8D-WMM的运动学、避障能力、面向避障作业的移动平台和末端操作器路径规划方法、满足在线避障要求的逆运动学优化方法等进行深入研究,并建立面向助老助残服务任务的8D-WMM系统实验平台,完成相关实验验证。由于8D-WMM含有非完整约束,不易得到自运动流形解析解,论文结合8D-WMM关节轴线的几何分布特点,基于运动等效思想,以向量代数为工具,对8D-WMM运动学进行了研究,求解了8D-WMM自运动流形的解析解;并将移动平台视为广义运动副,利用速度叠加原理完成了雅可比矩阵的求解。针对冗余度机器人在避障能力方面评价困难问题,通过对杆件自运动轨迹的空间度量,提出并建立了具有几何意义的冗余度机器人通用避障能力指标—避障活动度,通过平面3自由度冗余机器人和8D-WMM分析了避障活动度的求解方法,进而利用该指标分析了机器人杆件参数对上述两种机器人避障能力的影响。在路径规划方面,首先对8D-WMM的典型作业环境和典型障碍物进行了分析,继而利用8D-WMM自运动分析结果,结合机械臂关节构型的特点,给出了平顶、斜顶、曲顶等各类障碍物的可回避性判据,并分析了移动操作机可避障域的求解方法,最后给出了面向可避障域的移动平台路径规划算法和面向障碍物轮廓的机械臂路径规划算法。在面向避障的逆运动学优化算法方面,从自运动角度出发,借助自运动流形的求解结果,提出了一种更适于避障作业的冗余度机器人逆运动学优化算法,解决了现有算法在位移精度和计算量方面的不足。并通过平面3自由度机器人轨迹跟踪和8D-WMM执行窗口作业的仿真实例,验证了算法的可行性。最后,应用避障能力的分析结果,面向助老助残任务构建了8D-WMM的系统实验平台,完成了机械本体、控制系统硬件及软件的设计。在此基础上利用该平台完成了自运动流形、可避障方向域、可避障域求解算法和基于自运动流形的冗余度机器人运动规划算法实验,实验结果证明了论文理论研究的正确性和可用性。更多还原

【Abstract】 Mobile manipulator, a kind of robot system, is composed of mobile platform and manipulator installed on the platform, and can be widely used in elderly and disabled aid, disaster rescue, and explosives disposal, etc. The structural features of 8D-WMM show the characteristics of nonholonomic redundancy, so the problems of its motion planning are more complicated than mobile robot and traditional redundant robot. Furthermore, because 8D-WMM generally works in complicated environments with obstacles, it is meaningful to enhance its operating ability by use of the redundancy in non-structural environment full of obstacles. Nowadays, it is lack of systematic study in framework integration of WMM and inverse kinematics optimization facing obstacle avoidance throughout this field, which can not fully exert the flexible operating ability of this kind of robot in complicated environment. Therefore, this thesis focuses on theoretical exploration on motion planning method of 8D-WMM including kinematics, path planning, obstacle avoidance, and end effector operation. Besides, the 8D-WMM system was built for elderly and disabled aid, and experiments were carried out to testify theories.Because the 8D-WMM includes nonholonomic constraint, it is difficult to obtain analytical solution of self-motion manifold. Therefore, based on the theory of movement equivalence, this thesis carried through study on its kinematics and solved 8D-WMM self-motion manifold by combining geometric distribution characteristics of 8D-WMM joint axes and using the tool such as vector algebra. And it also got Jacobian matrix by using the speed superposition principle through regarding mobile platform as Generalized Kinematic Pair.To easily evaluate the obstacle avoidance capabilities of a redundant robot, this thesis proposed and established obstacle avoidance ability index of redundant robot which has intuitive geometric meaning in virtue of space measurement of pole self-motion trajectory-obstacle avoidance activity, whose solution is obtained through a planar 3-DOF robot, and further analyzes the influence of 8D-WMM framework size on its obstacle avoidance ability by using the index. In the aspect of path planning study, the typical operating environment and obstacle of 8D-WMM were analyzed firstly. Then the avoidable criterion of various obstacles such as flat top, slant, and dome, etc, was given by using the results of 8D-WMM self-motion analysis and combining the characteristics of arms joint configuration and the solution to the mobile manipulator’s obstacle avoidance area was analyzed. Finally, the path planning algorithm of the mobile platform facing obstacle avoidance area and manipulator facing the outline of obstacles were presented.In the study on inverse kinematics optimizing method for obstacle avoidance, from the perspective of self-motion, the thesis puts forward inverse kinematics optimizing method which is more suitable for redundant robot performing obstacle avoidance based on self-motion manifold in virtue of the results of self-motion manifold, which solved the deficiency of the present method in displacement accuracy and calculation quantity. Through the trajectory tracking of a planar 3-DOF robot and the simulation examples of 8D-WMM implementation window, the algorithm feasibility is validated.Finally, by use of the analysis results of obstacle avoidance ability, this thesis built 8D-WMM system experimental platform including the completion of the mechanical body design, the control system hardware, and software design aiming at the task of the elderly and disabled aid. With help of this platform, the thesis completed self-motion manifold experiments, avoidable obstacle direction field experiments, avoidable obstacle direction field algorithm verification experiments, and motion planning algorithm experiments of redundant robots based on self-motion manifold. The experimental results verified the correctness and availability of the theories.更多还原