【作者】 王伟东；

【导师】 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】 随着机器人技术的不断完善,移动机器人逐渐从室内结构环境走向室外非结构环境。在煤矿事故和城市废墟搜救、工程探险勘测、反恐防暴、军事侦察、星球探测等复杂环境领域得到广泛应用。国内外在该方向开展了广泛的研究,但如何提高移动机器人在复杂地面环境中的全地形通过性、机动性、抗振抗冲击性、越障性能和越障稳定性,以及系统可靠性,成为机器人成功应用的根本,也是目前该领域的研究热点和前沿问题。本文结合国家863计划项目,针对于恶劣环境的使用需求,对履带式移动机器人履带地面作用机理、移动手臂垂直动力学建模、移动手臂振动分析与抑制、自主越障动力学建模、自主越障动作规划和稳定性分析等方面展开了研究。论文首先针对于机器人系列化、标准化和规范化的需求,采用模块化思想研制了履带式移动机器人。介绍了机械系统和电气系统模块化设计,以及针对于特殊环境应用的特殊模块设计。建立了移动手臂运动学模型,利用此模型进行了作业臂尺寸综合和轨迹规划研究。履带与地面的相互作用是移动机器人驱动的动因,研究履带与地面的作用机理,建立反映机器人移动过程的动力学模型,是实现机器人快速机动的前提。基于计算地面力学建立了履带地面作用数学模型。将履带分成承重轮和纯履带部分,根据其对地面加载、卸载、再加载的特点分别建立模型,并基于结合点平衡条件建立完整的履带模型。在此基础上通过该模型分析了履带参数对不同路面通过性的影响。并基于地面-履带土槽测试系统,对不同结构参数和行驶参数的履带牵引特性进行了对比实验,得出了不同参数变化对牵引指标的影响规律。为全地形移动机器人行走系统设计、分析和验证奠定了基础。移动手臂为刚性较差的悬臂梁,在路面不平度随机激励下产生较大振动,从而降低机器人系统可靠性和手臂抓持稳定性。针对上述问题,首先应用拉格朗日方法建立了移动平台垂向动力学模型,并针对于手臂质量分布不均的特点,采用集中质量单元和Euler-Bernoulli梁单元建立了有限元离散化垂向动力学模型;进而将以上两种模型通过结点约束条件联立建立了整个移动手臂的垂向动力学模型。基于此模型,提出了利用高效的虚拟激励法和精细积分算法分析非平稳随机激励下的移动手臂动态响应的算法。分析了机器人悬架参数对振动吸收的能力,分析了移动手臂结构参数和姿态对抑振的作用。为机器人悬架设计和移动手臂振动控制提供了快速分析方法。针对于质心在机器人越障过程中起到的决定性作用,提出了利用质心坐标公式和机器人运动学建立的质心运动学模型,考虑了作业手臂姿态和前摆臂姿态对质心的影响。通过此模型进行自主越障动作规划,得到了机器人在越障过程中质心变化情况,分析了移动手臂姿态对跨越壕沟和垂直障碍的影响。并且利用质心投影法求取了越障稳定裕度。针对移动作业手臂动态特性会影响移动机器人越障性能和越障稳定性的现象,提出了一种基于动力学进行越障动作规划的方法。即首先通过牛顿欧拉法建立移动手臂越障动力学模型,并利用其逆动力学求解正动力学问题。在此基础上,利用ZMP(Zero Moment Point)稳定性判据,分析了移动手臂动态运动对跨越障碍的影响。同时基于质心运动学规划得到的越障姿态,求解了最优加速度。利用该方法规划了机器人跨越壕沟和垂直障碍动作,并同没有动作规划、只有运动学规划和动力学规划得到的越障能力进行了比较。最后在放射源处理履带式移动机器人上进行了手臂抓取实验、移动手臂振动实验和自主越障和稳定性实验,验证了论文理论研究及设计的正确性和可用性。更多还原

【Abstract】 With the gradual improvement in the robot technology, application field of the mobile robot become from the indoor structured environment to the outdoor unstructured environment. They are employed in mine disaster and city ruin rescue, engineering exploration, anti-terrorism, batter field and aerospace exploration. In these fields, some special design and analysis method should be used to improve trafficability. So in this paper, the interaction of track-terrain, vibration dynamic model of mobile manipulator, accurate and highly efficient algorithms for mobile manipulator non-stationary random responses, motion planning and stability analysis of climbing up an obstacle are introduced.The mobile robot system is designed by the module partition method which makes the robot serialization and standardized. Some special designs are used for the unstructured environment, such as suspension system, anti-explosive and radiation protection and waterproof. And then the kinematics model of mobile manipulator is built. Using this model, the geometry parameters identified method and trajectory planning method of mobile manipulator are obtained.The effect of the terrain physical parameter on the trafficability in the soft terrain is presented. The interaction model of robot track and terrain are built based on terramechanics. At first the track system is divided into three partitions, namely front road wheel, middle track and the rear road wheel. In the different partition, the terrain state under the track is in the different process of loading, unloading and reloading. So the models in the different partitions are different. And then the three parts are connected on the common point by the force balance, and the whole model of the track system is obtained. Using this model the effect of the track parameters on the trafficability is analyzed, and the maximum drawpull which the terrain can afford is obtained. At last the experiments plat is introduced, and some experiments are design to validate the vibration dynamic model and the analysis results. These results are valuable for the design of the all terrain mobile robot.The random vibration due to road roughness has some effect on mobile manipulator. The reliability and the stability are reduced. First vibration dynamic model of the mobile plat is built by the Lagrange model, and the dynamic model of the manipulator is built with finite element method (FEA). And then the two models are rebuilt into whole model of the mobile manipulator by the force balance on the common point. Using the accurate and highly efficient pseudo-excitation method (PEM), precise time-integration and the vibration dynamic model, the transient power spectral density (PSD) of vehicle in nonstationary random vibration exicitation is obtained. For different parameters of the suspension and different posture of manipulator, the performance of the vibration absorbing is analyzed. These results can guide design the suspension of the mobile manipulator.Because the center of gravity (CG) plays an important role in the process of climbing up an obstacle, the CG kinematics model is built. Especially the effect of the manipulator postures is included. Using this model, the CG change situation is obtained in the process of climbing an obstacle, and the maximum height of the obstacle which can be climbed up is obtained, and the stability angle margin is obtained too. At last the relationship between the posture of the manipulator and the height of the obstacle which can be climbed is obtained.The dynamic performance of the mobile manipulator affects the obstacle-climbing performance. So the dynamic model of the mobile manipulator is built by the Newton-Euler method. Using the dynamic model and zero moment point (ZMP), dynamic effect of the mobile manipulator on the robot stepping over a ditch and climbing up an obstacle are presented. The optimal accelerations of the mobile manipulator and the robot are obtained by the dynamic model. At last the compare of obstacle performance of the robot in the case of no any motion planning, kinematics motion planning and dynamic motion planning is obtained.Finally, several experiments are designed for the trafficability analysis of the mobile manipulator. The grasping test of mobile manipulator, the vibration test in the rough terrain and the autonomous motion planning of climbing up an obstacle are designed. These test results validate the analysis results.更多还原