直角坐标柔性机器人操作臂机电耦合动力学及振动特性研究

发布时间：2018-01-10 07:34

本文关键词：直角坐标柔性机器人操作臂机电耦合动力学及振动特性研究　出处：《中国矿业大学》2016年博士论文　论文类型：学位论文

【摘要】：直角坐标机器人是工业机器人领域的重要组成,在机械加工、精密装配、上下料、喷涂等工艺中具有重要的应用。机器人操作臂是执行操作任务的关键部件,其结构性能和动态特性对直角坐标机器人的操作精度具有重要影响。传统的机器人操作臂采用刚性结构,整体结构较为笨重,增加了系统的体积质量和能耗。柔性操作臂具有轻质、灵活、能耗低等特点,能够有效降低机器人操作臂的体积质量,符合机器人轻型、高速、集成化的发展要求。然而,由于结构刚度低、阻尼小,柔性操作臂在执行任务、尤其是高速操作的过程中极易产生弹性变形和残余振动,严重影响其末端执行器的操作精度和效率,甚至导致操作失败或经济损失。为此,深入研究柔性操作臂的动力学及振动特性,既是柔性操作臂振动控制的基础,也是有效解决机器人由刚性向柔性发展的关键。作为典型的复杂机电系统,机器人伺服驱动与执行机构之间存在复杂的机电耦合关系,通过传动系统的作用而产生系统激励;对于高速轻型结构而言,机电耦合因素产生的系统激励将更为凸显。由于柔性操作臂模态较低,系统激励对其动态特性的影响将更显著,而机械结合部和柔性因素的存在进一步增强了系统耦合因素的影响。因此,研究柔性操作臂的振动特性,应充分考虑系统耦合因素的影响。本文在国家自然科学基金项目、教育部博士点基金项目、江苏省科技支撑计划项目和江苏省普通高校研究生科研创新计划项目的资助下,结合直角坐标机器人的结构和运动特征,基于理论建模、数值仿真分析、虚拟样机实验和实验系统测试手段,对柔性操作臂机电耦合动力学及振动特性开展研究。研究工作主要包括:(1)建立了直角坐标柔性机器人的动力学模型,完成了实验系统构建。基于Hamilton变分原理推导了柔性操作臂平移、伸缩和斜向运动特征下的动力学方程,分析了不同运动特征下柔性操作臂的振动特性;探讨了柔性操作臂匀速运动振动响应的初始条件,通过分析加速阶段柔性操作臂的振动响应,确定了匀速运行阶段振动响应的初始条件,基于此对柔性操作臂匀速运行的振动特性进行分析,并与虚拟样机实验结果进行对比验证;采用直角坐标机器人本体结构、环氧树脂材料柔性操作臂和螺栓连接结合部,搭建了直角坐标柔性机器人实验系统,介绍了实验系统的结构组成及其模拟柔性机器人系统耦合因素的可行性,对各运动特征下柔性操作臂的振动响应特性进行了实验测试分析。(2)研究了柔性操作臂结合部弹性约束模型及动态特性,探讨了结合部弹性约束的作用机理。考虑线约束和扭转约束作用,建立了螺栓结合部的弹性约束模型,根据虚功原理确定了柔性操作臂的边界约束条件,推导了其频率方程和振型函数,分析了柔性操作臂的频率和振型特性,揭示了结合部弹性约束对柔性操作臂模态特性的影响;采用灵敏度方法分析了线约束和扭转约束对频率的影响程度,给出了结合部的弹性约束区域,基于此对频率曲线进行拟合,表征了结合部约束刚度与频率之间的关系,分析了结合部弹性约束对柔性操作臂振动特性的影响;通过模态测试实验验证了弹性约束模型的有效性,为研究结合部弹性约束下柔性操作臂的机电耦合动态特性提供了理论模型。(3)开展了柔性操作臂机电耦合动力学建模及联合仿真虚拟实验。考虑系统存在的耦合关系,将驱动系统、传动系统和负载执行机构作为整体,建立了包含电磁系统与机械系统的系统全局耦合关系和物理模型,采用机电分析动力学方法,推导了系统的机电耦合动力学方程;采用Matlab/Simulink建立了系统的动力学仿真模型,对电机的输出转速和移动基座的运动特性进行分析,揭示了机电耦合作用下系统的运动波动规律;基于系统动力学仿真模型与虚拟样机模型,采用Matlab/Simulink和Adams/controls建立联合仿真模型,对机电耦合作用下柔性操作臂的振动特性进行联合仿真虚拟实验,为研究柔性操作臂的参数振动特性奠定了基础。(4)分析了机电耦合作用下柔性操作臂的参数振动特性和稳定性。表征了移动基座的运动特性方程,基于此推导了运动波动下柔性操作臂的参数振动方程,分析了柔性操作臂的参数振动特性,验证了运动波动的影响;根据柔性操作臂参数振动的稳态功率流特性,直观展现了柔性操作臂的振动能量分布,分析了结合部弹性约束对参数振动及稳态功率流的影响;采用直接多尺度方法推导确定了柔性操作臂参数振动的稳定性边界,讨论了结合部弹性约束和末端执行器负载对系统失稳区域的影响,通过实验测试分析了柔性操作臂的参数振动特性,验证了理论模型及分析结果的正确性。本文所取得的研究成果对深入开展多耦合状态下柔性操作臂的动力学和振动特性具有重要的指导意义,为柔性操作臂的机电耦合振动控制奠定了理论基础,对柔性机器人的集成设计具有重要的实际应用价值。
[Abstract]:The Cartesian coordinate robot is an important component in the field of industrial robots, mechanical processing, precision assembly, loading and unloading, has important applications in spraying process. The robot manipulator is a key component of performing tasks, has an important influence on the precision of operation of Cartesian coordinate robot's structure performance and dynamic characteristics of the robot manipulator. The traditional rigid structure, the whole structure is relatively heavy, increases the volume quality and energy consumption of the system. Flexible manipulator has the advantages of light weight, flexible, low energy consumption, can effectively reduce the volume and quality of the robot manipulator, the robot with light, high speed development, the requirement of integration. However, due to the structure of low stiffness, small damping flexible manipulator, in the execution of a task, especially easy to produce elastic deformation and residual vibration during high speed operation, seriously affect the end effector operation precision and efficiency Rate, even leading to operation failure or economic loss. Therefore, in-depth study of dynamics and vibration characteristics of flexible manipulator, flexible manipulator is based on vibration control, but also effectively solve the key from rigid to flexible robot development. As a typical complicated electromechanical system, existing electromechanical complex coupling relations between the robot and servo actuator and, through the transmission system of the incentive system for the high speed light effect; structure, incentive system to produce electromechanical coupling factors will be more prominent. Because the flexible manipulator system mode is low, incentive effect on its dynamic characteristics will be more significant, and the combination of mechanical and flexible factors exist to further enhance the effect of coupling system factors. Therefore, the vibration characteristics of flexible manipulator, should fully consider the influence factors of the coupling system. Based on the National Natural Science Foundation Project fund for the doctoral program of Ministry of education, Jiangsu province science and technology support program and the Jiangsu Province ordinary university students scientific research innovation project funding, combined with the structure and motion of the robot, based on theoretical modeling, numerical simulation, virtual experiment system and experiment test method, carry out research on electromechanical flexible manipulator the coupling dynamics and vibration characteristics. The main research work includes: (1) to establish the dynamics model of Cartesian flexible robot, the experimental system is constructed. The Hamilton variational principle is derived based on the flexible manipulator of translation, scaling and oblique dynamic equation of motion characteristics, analysis of the vibration characteristics of different motion characteristics of flexible manipulator the effects of initial conditions; flexible manipulator motion vibration response, through the analysis of vibration acceleration stage of flexible manipulator to determine the response. The uniform operation stage of vibration response of the initial conditions, the analysis of the vibration characteristics of flexible manipulator based on uniform operation, and compared with the experimental results by using virtual prototype; ontology structure of Cartesian coordinate robot, flexible manipulator and epoxy resin bolt connection with the Department, build a Cartesian flexible robot experiment system is introduced the feasibility of structure experiment system and flexible robot system coupling factor simulation, the vibration response of the motion characteristics of flexible manipulator are tested and analyzed. (2) research on the flexible manipulator with elastic constraint model and dynamic characteristics, discusses the interaction mechanism of elastic restraint. Line constraint and torsion considering the effect of constraint, a bolt with elastic restraint model, according to the principle of virtual work boundary constrained flexible manipulator were determined. The conditions, the frequency equation and modal function is derived, analyzed the frequency and vibration characteristics of flexible manipulator, reveals the combination of elastic restraint effect on flexible manipulator modal characteristics; using sensitivity method to analyze the constraints and influence on the frequency of torsional constraints, given the combination of elastic constraint region. The fitting of the frequency curve based on the characterization of the relationship between joint constraint stiffness and frequency. The analysis of elastic restraint effect on the vibration characteristics of the flexible manipulator; through modal testing experiments to validate the elastic constraint model, provides a theoretical model for the study of dynamic characteristic of electromechanical coupling of elasticity constraints flexible manipulator. (3) carried out a flexible manipulator electromechanical coupling dynamic modeling and joint simulation virtual experiment. Considering the system coupling relationship exists, the drive system, transmission system The actuator and load as a whole, has established the system global coupling relation and physical model including electromagnetic and mechanical systems, the electromechanical dynamics analysis method, the electromechanical coupled dynamic equations of the system are derived by Matlab/Simulink; established the system dynamics simulation model, analyzed the movement characteristics of the output speed of the motor and the mobile base, revealed the movement fluctuation of the electro-mechanical coupling system; system dynamics model and simulation based on virtual prototype model, using Matlab/Simulink and Adams/controls to establish a joint simulation model, the vibration characteristic of electromechanical coupling flexible manipulator joint simulation virtual experiment, laid the foundation for the parametric vibration characteristics of flexible manipulator (4.) parameters of vibration characteristics and stability of electromechanical coupling flexible manipulator is analyzed to characterize the mobile. The base motion equations, based on the derived equations of motion parameters of vibration fluctuation of flexible manipulator, the parameters on the vibration characteristics of flexible manipulator, and verifies the effect of motor fluctuations; according to the steady-state power parameters of flexible manipulator vibration flow characteristic, intuitive display of the vibration energy distribution of flexible manipulator, analyzes the elastic constraints on the parameters affecting the vibration and steady-state power flow; using the method of multiple scales is to determine the stability boundary of flexible manipulator vibration parameters, discussed the elastic constraints and end effector load influences of instability zones on the system with the parameters, vibration characteristics of flexible manipulator are analyzed through experimental test, the correctness of the to verify the theoretical model and analysis results. The main achievements of the thesis are to carry out the dynamics and vibration characteristics of flexible manipulator under the coupling of multi It has important guiding significance, laying a theoretical foundation for the electromechanical coupling vibration control of flexible manipulator, and has important practical application value for the integrated design of flexible robot.

【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TP242.2

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