基于柔顺力控制的航发叶片边缘七轴联动数控砂带磨削方法及实验研究

This project puts forward a grinding method on seven-axis simulaneous with abrasive belt based on active compliance force control to machining the complex edge of aero engine blade which has the uncertainty deformation, will develop the force controller which integrated into the NC abrasive belt grinding testing devices, and carry out the research seven-axis synchronous belt grinding mechanism by compliance control. Based on impedance control of force-position hybrid mode and force sensor integration principle, the mathematical model will be established to deduce the algorithm of seven realistic axes movement with decoupling approach to force-position hybrid condition, and done the numerical calculation and co-simulation, then developed constant pressure active compliance controller with micro-actuated element,finally through the real-time force control achieved intelligent track to the contour normal error of blade edge with deformation to grinding with low-damage. At the same time the experiment will be carried out on the NC high efficiency and precision abrasive belt grinding equipment under seven-axis compliance control, where there is a virtual instrument to monitor grinding process parameters and the apparatus to check blade edge's accuracy and surface property，also build up a mapping model concerning the grinding process parameters matching evaluation and propose concepts about characteristics of the grinding qualified edge mapping function and principle, such as the force interaction between the belt and the material of blade, removal mechanism, belt wear mechanism, the grinding error control mechanism, relations between the grinding conditions and the surface properties of blade edge. The project is a important fundamental research on high efficiency to machining qualified edge after aero engine blade precision forging，and is a great innovation of traditional NC belt grinding method that based on predetermined point position trajectory, further investigation into the mechanisms of abrasive belt grinding sculptured surface by compliance control has great significance and wide prospect in regard to mastering the key technology of new generation aero-engine manufacture and enhancing China's advanced grinding technology application level.

本项目提出一种对具有不确定性变形的复杂航发叶片边缘进行七轴联动砂带磨削主动柔顺控制方法，研制力控制器实现在数控砂带磨削实验设备的集成，并开展柔顺控制的七轴联动砂带磨削机理研究。基于力位混合模式下阻抗控制和传感器集成原理，建立基于力位解耦的七轴联动控制数学模型，并进行数值计算及联合仿真，研制具有微致动恒压主动柔顺控制器，通过力控制实时智能跟踪叶片边缘法向轮廓变形误差实现边缘的精准低损伤磨削。开展柔顺控制的七轴联动高效与精密砂带磨削试验研究，系统建立柔顺控制砂带磨削工艺参数与叶片成缘质量特性映射规律模型，如材料与砂带交互作用力、材料去除机理、砂带磨损机理、柔顺磨削误差控制机制、磨削条件与成缘表面性能的关系等。本项目关于柔顺七轴联动砂带磨削基础性研究，是对传统基于预先有确定性轨迹点位数控磨削方法的重大创新，对掌握航发叶片核心关键工艺技术和提升我国先进磨削技术应用水平具有重要意义。

随着我国新一代大推比军用航空发动机项目研制实施，要求叶片进排气边缘（最薄厚度0.1mm）具有对气动外形极具敏感变半径（最小半径0.05mm）并与叶身圆滑连接过渡的精密级光滑边缘。然而航发精锻叶片边缘在铣削毛边后不可避免地产生变形，加之其叶片材料本身的难加工性，导致其最终加工成缘率较低，亟待需要研究针对航发叶片变形扭曲极薄边缘的加工新方法。. 本项目基于砂带磨削曲面成形原理，提出了基于柔顺力控制方式航发叶片边缘高精高一致性加工方法，通过理论分析、计算机仿真和加工实验相结合的方式建立了砂带磨削过程叶片边缘主动柔顺力控制模型，进行了柔顺控制新功能控制部件原型装置研制，提出了航发叶片边缘为典型代表的自由曲面加工轨迹自适应规划方法，开发了基于测量误差重构进行补偿修正叶片边缘的加工技术，构建了七轴砂带磨削轨迹模型，设计并开发了七轴砂带磨削成缘轨迹规划软件原型和搭载力控制的多轴伺服控制系统，形成了具有主动柔顺力控制的砂带磨削实验系统，开发了基于主动柔顺控制器通过力信号采集并多轴伺服控制的调控跟踪叶片边缘变形误差实现叶片边缘的系统化加工技术，提高了航发叶片边缘成缘的形状精度、表面质量，对推动国产航发叶片核心关键工艺技术掌握具有重要科学意义。