【作者】 高振；

【导师】 葛运建； Dan Zhang；

【作者基本信息】 中国科学技术大学 ， 模式识别与智能系统， 2009， 博士

【摘要】 制各随着高等空间机构学和机器人技术的发展,以并联机构为理论依托的并联机器人作为机器人技术的一个重要分支,对其理论和应用的研究日趋活跃。尽管不少学者已经对并联机构的构型、运动学、动力学、工作空间及奇异性等方面做了不同程度的研究,但是大部分工作仍然集中于以传统的Gough-Stewart为代表的六自由度并联机构。由于大多数工业操作并不需要全自由度设备,比如机械加工领域五自由度已满足要求,电子元件装配的拾放操作只需四个自由度,因此工业界和学术界对少自由度的新构型并联机器人的研究需要显得日益迫切。而空间三自由度并联机构作为少自由度构型里最有发展前景的一类,对其构型的研究将有利于推动少自由度并联机器人的深入发展和广泛应用。由于机构的串联或并联从哲学观念出发是对立统一的,混联机器人将综合两者的优点,在某些特殊的应用场合发挥作用,同时丰富机构学研究的内涵。本文以此为背景,深入研究了若干种空间三自由度并联/混联机构的新构型,提出了几种重要的性能指标的建模及优化方法,并就具体的应用领域进行了有益的探索和挖掘。全文的主要研究工作概括如下:研究了空间少自由度并联/混联机构的设计优化理论与方法,对并联/混联构型下的三自由度机构进行了拓扑分析。阐述了性能优化过程中采用的遗传算法与径向基神经网络的融合算法,把Pareto多目标优化的理论引入到基于并联机器人构型的多性能优化中,给出了并联机器人在一定几何约束条件下的性能优化的Pareto前沿集合。基于一种新颖的Tripod并联机器人机床(具有二个移动自由度及一个转动自由度,采用了平行四边形机构来增加三条支链的刚度),提出了采用Jacobian矩阵的全局刚度表征方法,给出了全局刚度优化的原理与结果。提出把并联机器人多误差源抽象成单一的假想误差源,并基于一种进化神经网络对误差进行补偿。探讨了一种基于3SPS+RPR构型,利用杆件和关节本身柔顺性实现微动操作的柔性混联机构,并运用运动静力学模型建立了主要性能指标,对包括全局刚度、灵活性及操作能力在内的多项性能指标进行了多目标优化。尝试融合径向基神经网络和混联机构的逆向运动学模型求解其正向运动学模型数值解。通过对一体化三维加速度传感器以及仿土拨鼠救援机器人的研究,拓展并联/混联机构应用的新视角。基于全解耦并联弹性体结构的三维加速度传感器因采用笛卡尔直角坐标系结构,三个方向的加速度通过三条支链上的弹性应变分别测得,由于两两正交,在结构上实现了多维加速度的自动解耦。并对3RRPRR柔性并联机构的构型、各向同性等进行了分析,对传感器结构尺寸变化下弹性体的应力应变进行了有限元分析。并研制了相应的物理样机,重力法标定试验结果验证了原理的可行性和样机本身的性能。针对矿难危险环境下实施机器人救援的性能需求进行了分析,提出了一种仿土拨鼠机器人及其颈部冗余驱动机构。阐述了仿土拨鼠机器人体系结构与模型,对其颈部4UPS+PU冗余驱动的混联机构进行了设计与分析,探讨了仿土拨鼠机器人在矿难危险环境下应用的可行性,并基于Adams虚拟样机技术对4UPS+PU机构的运动学、动力学等进行了仿真研究。更多还原

【Abstract】 With the development of the theory of anvanced spatial mechanism and the technology of robotics,parallel mechanisms based parallel robots have been one important branch of robotic technology.Forthermore,the research activities of the theories and applications of parallel mechanisms and parallel robots is becoming much hotter.However,although many scholars have done the intensive investigations on the dimension synthesis,kinematics,dynimics,workspace and singularity of parallel mechanisms,most of the existing work regarding arallel mechanisms was built upon the concept of traditional Gough-Stewart mechanism type.Since full degree-of-freedom devices are not necessary for most industrial operations,i.e.the machining operations only require a maximum of five axes,and the motion of pick-and-place for the assembly of electronic elements only require a maximum of four degree-of-freedom,new configurations with less than six axes(degrees of freedom) would be more appropriate for industry and academia.Tripod is one type of parallel mechanism with three degrees of freedom,and it can implement the basic three axes machining,by combining with the XY gantry,it can conduct four degree-of-freedom or five degree-of-freedom machining.Therefore,tripod mechanism is targeted as the main configuration for the development of parallel manipulators.Because of the opposition and unitarity of serial mechanisms and parallel mechanisms in philosophy,the hybrid mechanisms can be built through the combination of parallel and serial mechanisms and play an important role in some specific application background.The thesis will do the deep investigations on the spatial three degree-of-freedom parallel mechanisms in the following aspects:1. propose sevseal types of novel configurations,2.develop some important approaches of for the modeling and optimization of performance indices,3.explore on the specific application fileds of proposed parallel/hybrid mechanisms.The main work of the full thesis is generalized as follows:Study on the theories and approaches for design optimization of spatial less degree-of-freedom parallel/hybrid mechanisms.Give the degree-of-freedom computing criteria of the parallel robotic mechanisms for more reasonable kinematic structures using Chebychev-Grubler-Kutzbach criterion.Study on topology of the spatial three degree-of-freedom parallel/hybrid mechanisms.The globan stiffness and other indices and built based on the guidance of the redefined Jacobian matrix.The integrated algorithm of multi-population genetic algorithm,radial basis function network and Pareto method are introduced for the multi-objective optimizations of performance indices.The Pareto-optimal frontier sets under some geometrical constraining is given.Design a tripod parallel kinematics structure,of which the end-effecter(the moving platform) has three independent motions—two pure translations and one pure rotation.The output link of a planar parallelogram mechanism will remain in a fixed orientation with respect to its input link,and the parallelogram can ensure the desired output,in terms of translation and rotation.The use of the parallelogram structure can greatly increase the stiffness of the legs.Jacobian matrix based global stiffness modeling and optimization is developed.Study on the error calibration and compensation with the proposed cooperative evolutional network.In this error model, all the error sources are considered as a single one which affects the precision of gripper through the bias of joint variables.A 3S(?)S+RPR typed compliant hybird micromanipulator with flexure joints which encompasses three degrees of freedom and can produce motion on a microscopic level is proposed.The detailed design of motion systems for the machine structure is introduced.The multi-objective optimizations of global stiffness,dexterity and manipulability are conducted.The integration of inverse kinematics and radial basis function network is poporsed to sovel the forward kinematics problem of the proposed compliant hybird micromanipulator.Through the researches of the integrated three dimensional accelerators and the marmot-like rescuing robotics,the application viewpoints of parallel/hybrid mechanisms are extended.A novel design of a multidimensional acceleration sensor is proposed based on 3RR(?)RR decoupling parallel mechanism for kinetic information acquisition,specifically for measuring human motions.The translational elements of three perpendicular legs are served as elastic body which is manufactured by aluminium alloy,The finite-element analysis of resultant stress,strain and deformations is conducted based upon different input conditions to show the reliability of the proposed sensor structure.The physical prototype is developed.The calibration experiment based on gravity is performed to validate the correctness of related principle and performances of the prototype itself.Mine rescue robot is a kind of intelligent robots which can work in a complex and dangerous underground environment and be used for detection human beings in many aspects.The performance requirements of robot rescue in hazard place of mine accident are analyzed.The marmot-like rescuing robot and its 4UPS+PU redundant driven hybrid mechanism of neck is proposed.The feasibility of its application in the underground environment of coal mining accidents for assitant rescuing is discussed. The simulations of kinematics and dymanics for the proposed 4UPS+PU mechanism are conducted based on the dummy prototyoe technology.更多还原