本论文面向航空航天复杂结构件高效加工的需求，以五轴并联加工机器人为研究对象，围绕性能评价和优化策略两方面核心内容开展研究，建立参数优化方法，指导并联加工机器人设计。具体研究内容如下：结合能量流动过程和功率方程，建立了考虑支链能量变化的能量利用率模型，揭示了机器人支链传递能力对能量利用率的影响机理，进而建立了综合末端运动状态的并联机器人功率传递性评价指标体系，为量化探究机器人设计参数对能量利用率的作用规律和以能量利用率为优化目标的参数设计提供了理论依据。为评价机器人加工过程中受多类载荷时抵抗弹性变形的能力，以弹性体模型为基础，研究了设计参数与机器人受力响应情况间映射关系。通过节点缩聚及拼接技术，建立了高精度参数化五轴并联机器人弹性体模型。基于时变载荷、重力等外力作用时机器人的节点位移及变形能，建立了加工机器人动、静刚度评价体系。聚焦无颤振条件下的加工参数耦合关系这一影响并联加工机器人材料去除效率的关键因素，完成了“数学判据-载荷预估-系统特性”五轴并联加工机器人切削稳定性分析流程。通过机器人与刀具间的导纳耦合，获得了设计参数与临界加工参数间数学模型，最终建立了稳定加工条件下的极限切削用量评价方法。为提高优化效率，以参数灵敏度为依据，量化分析了设计参数对各优化目标的影响能力，建立具有分层递阶格式的高效加工并联机器人参数优化策略。以高效加工为最终导向，以功率传递性和极限切削用量指标为纽带，以动、静刚度为约束，实现了五轴并联高效加工机器人机构尺寸参数和部件结构参数的优化设计。对比发现，优化后机器人在运动能耗、切削稳定性等方面上均优于优化前结果。高效加工五轴并联加工机器人参数优化方法通过揭示本体设计参数与高效加工相关性能函数间的影响机理，基于以参数为变量的能量利用率、材料去除效率模型评价相应性能、基于以性能为目标函数的优化策略求解设计参数，实现机器人“性”和“度”的有机结合。研究成果对完善并联机器人性能分析及设计理论，推进并联高效加工机器人化装备的应用有重要意义。
Oriented to deal with the requirement of efficient machining of complex aeronautical structural components, this dissertation focuses on the core issues in robot design, performance evaluation and dimension synthesis. The four key research contents are conluded as energy efficiency evaluation, stiffness modeling, material removal rate analysis, which are descaibed in detail as follows:With the modeling of energy flow in robots and power equation, the interaction mechanism between energy change rate of chains and energy efficiency is revealed. On this basis, a novel energy efficiency model considering the energy characteristics of chains is built. Furthermore, quantitive indices for power transmissibility of parallel robots are established taken the effect of kinstate of the end effector. The proposed indices not only offer a quantitive method of studying the mapping relationship between design parameters and energy effciciency, but provides theoretical basis for the development of high energy-efficient paralle robots as well.To ensure the machining quality and precision, stiffness should be considered in the design process of machining robot. Based on the elasto-dynamic model, the response of robot under different design parameters and external loads is analyzed. By condensating-splicing method, the connection relationship of components in chains is truly reflected. Then a parameterized elastic body model of five-axis parallel robot with high-precision is established. Based on the node displacement and deformation energy storing in robot under the multi-form and multi-source external loads such as the cutting force and the gravity, the dynamic and static stiffness evaluation system of the machining robot is established. The coupling relationship of machining parameters is the key factor affecting the material removal rate of parallel machining robots. The cutting stability lobes of the 5-axis parallel machining robot is obtained with the help of mathematical criterion, load estimation and system modal parameter analysis. By receptance coupling substracture analysis, the relationship between design parameters optimization and material removal rate improvement is derived. To evaluate the maximum removal rate, the limit cutting volume is propsed as index, which reveal the influential mechnism of design parameters and practical performance. With high machining efficiency as final goal, power transmissiblity and limit cutting volumn as objective functions and stiffness performance as constraint, the optimal design of geometrical and structural parameters in 5-axis parallel machining robot is carried out. Based on the parameter sensitivity, influence between multi-parameters and multi-objectives is quantitatively analyzed. A hierarchical optimization process is proposed to increase the optimization efficiency.Through simulation comparison, the optimized 5-axis parallel machining robot consumed less energy and has better cutting stability than the robot before optimization. The five-axis parallel module in a mobile machining robot. The experimental results showed that energy efficiency and machining capacity of robot have been significantly improved.
