【作者】 刘冬；

【导师】 丛明；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2010， 硕士

【摘要】 本文以提高换刀速度和可靠性,研究换刀过程传动特性为目的,结合MDH卧式加工中心分析设计双凸轮联动自动换刀装置的关键结构,利用Pro/E、ADAMS和ANSYS从多方面开展基于虚拟样机技术的双凸轮联动自动换刀装置多体动力学与有限元联合仿真研究。重点探讨了虚拟样机的建模、装配、有限元分析、多刚体动力学仿真以及柔性多体动力学仿真,理论方法及仿真结果对指导工程实践、改进系统设计、提高产品性能具有重要意义。在调研国内外自动换刀装置发展及其研究现状基础上,针对传统的凸轮式自动换刀装置换刀时间长、可靠性低等缺陷,结合MDH80卧式加工中心的结构、尺寸,设计了一种复合凸轮(包括弧面分度凸轮和沟槽凸轮)机械手换刀与盘形凸轮主轴松拉刀联动的自动换刀装置,分析了其工作原理,匹配运动循环图并优化了各类凸轮机构运动规律。在Pro/E中建立了双凸轮联动自动换刀装置虚拟样机,并对整体结构进行干涉分析与运动仿真。利用ADAMS对装置的两个主要部分复合凸轮换刀机构以及盘形凸轮松拉刀机构进行多体动力学仿真分析,研究了凸轮传动副的接触碰撞力和机构输出位移、角速度、角加速度等啮合传动的动态响应特性,不同载荷工况对机械手换刀特性的影响等。采用ANSYS计算盘形凸轮的应力和变形。最后分析了装置产生振动和磨损的原因。针对弧面分度凸轮机构,基于柔性动力学理论和接触力学方法,利用有限元和虚拟样机技术,考虑凸轮轴柔性变形,采用非线性等效弹簧阻尼模型建立间隙处的接触碰撞模型,采用库仑摩擦模型考虑间隙处的摩擦作用,建立了刚柔耦合弧面分度凸轮间隙接触碰撞动力学模型。通过数值仿真,研究了刚柔耦合特性和间隙对机构传动特性的影响规律。研究表明该动力学模型较好地模拟了复杂弧面分度凸轮传动的柔性变形和接触冲击等特性,仿真结果为弧面分度凸轮系统动力学研究提供了理论指导和参考数据。采用有限元方法建立了弧面分度凸轮啮合传动的接触模型,探讨了其在外载条件下的接触响应特性,并对有限元结果进行了分析,得到了该传动应力和变形的一般规律,为强度设计计算提供了理论依据。更多还原

【Abstract】 For the purpose of improving the speed and reliability of ATC and studying the transmission characteristics of tool-changing processes, this paper designs the structure of dual-cam linkage drive ATC by analyzing MDH horizontal machining center and develops the simulation research on multi-body dynamics and finite element co-simulation of the dual-cam linkage drive ATC in many ways based on the virtual prototype technology utilizing Pro/E, ADAMS and ANSYS. Specially, the modeling, assembling, FEA, multi-rigid-body dynamics simulation and flexible multi-body dynamics simulation of the virtual prototype is focused on, which theoretical methods and simulation results will have great significance in practice, system design and product performance.In the second and third parts of the article, in the first place, to solve the problem, long tool-changing time and low reliability, of the traditional cam-type ATC, considering the structure and dimension of the horizontal machining center MDH80, it designs a dual-cam linkage drive ATC with a composite cam, which is composed of a globoidal indexing cam and a slot cam, controlling manipulator movement and a plate cam controlling tool bar movement, analyzes its working principle, matches the motion cycle chart and optimizes the motion law for various types of cam mechanisms. In the second place, using Pro/E, the virtual prototype of dual-cam linkage drive ATC is created, and the interference and simulation analysis of the whole structure are carried out. Then, using ADAMS, both the multi-body dynamics simulation of the two main parts, composite cam drive tool changer and plate cam drive tool push-pull mechanism, of the device, and the contact forces in cam-drive pair together with the dynamic response characteristics such as displacement, angular velocity and angular acceleration of mechanism, and the effect of different load conditions to the manipulator tool-changing are obtained. At last, we utilize ANSYS to calculate the stress and deformation of plate cam. Thus, the reasons for vibration and wear of mechanism are received.In the fourth and fifth parts of the article, to begin with, by multi-body dynamics theory and contact mechanics, aimed at the globoidal indexing cam mechanism and in consideration of the flexible deformation of cam axis, it uses the finite element and the virtual prototype technology to set up a contact dynamics model based on the nonlinear equivalent spring-damp model and a contact-impact dynamics model and an analysis method on rigid-flexible coupling of a globoidal indexing cam with clearance based on the Coulomb friction model which friction effect is considered. Next, the characteristics of rigid-flexible coupling and the influence law of clearance affecting to the transmission characteristics by numerical simulation are investigated. It reveals that the dynamics model can effectively deal with the transmission characteristics of complex globoidal cam with the effect of flexibility and contact-impact and the simulation results can provide basic data and valuable theoretical basis for further research on dynamics characteristics of globoidal indexing cam transmission systems. Finally, the transmission contact model of a globoidal indexing cam mechanism is established by using the finite element method, the contact response characteristics are discussed in exterior loads, the finite element analysis results are analyzed, and the general law on force and deformation characteristics of this transmission is obtained, which will offer theory gist for the intensity designed in this transmission.更多还原