Application of Parallel Link Manipulators in the High Speed, High Accuracy Domain

本研究主要探讨并联机械手应用于高速、高精度六轴定位的可行性，如镜面对准、表面精加工、机械加工及机器人操作等。第一阶段的研究工作已经成功地证明了Stewart平台型并联机构是可行的，并且与传统的串联机构相比具有显著的优势。目前的研究阶段包括七项任务，旨在建立一台用于飞机涡轮发动机叶片精加工操作的原型机床。第一个研究任务是评估“动支承点”平台设计的效益，并决定是否应该采用它或传统的平台概念进行进一步研究。“移动支承点”设计是这样一种设计，在这种设计中，执行器供力不随着平台的移动而移动。第二项任务涉及建造一台能够正常工作的机器，该机器能够执行喷气发动机叶片精加工所需的操作。任务三要求实现在第一阶段研究中开发的前馈控制器。第四项任务是对系统性能进行实验测量和控制器的优化设计。任务五活动将测试在前面的任务中开发的系统，并评估其对飞机涡轮发动机叶片执行精加工操作的能力。第六项任务将系统测试扩展到其他类型的部件。任务7研究了另一种平台改造，它涉及到使用压电元件来实现高精度、高频率的运动。其目的是通过第三阶段的工作来跟进第二阶段的工作，以生产在第二阶段开发的系统的商业版本。这项工作将对机床行业产生影响，该行业显然需要能够降低成本和提高质量的创新概念。

This research focuses on the feasibility of using parallel link manipulators for high speed, high precision six axis positioning applications such as mirror pointing, surface finishing, machining, and robotic manipulation. A first phase research effort has successfully demonstrated that the Stewart Platform type of parallel link manipulator is feasible and has significant advantages over conventional serial link mechanisms. The current phase of research, comprising seven tasks, addresses the building of a prototype machine tool for finishing operations on aircraft turbine engine blades. The first research task evaluates the benefits of the "moving bearing point" platform design and determines whether it or the conventional platform concept should be adopted for further study. The "moving bearing point" design is one in which the actuator supplying force does not move as the platform moves. Task two involves building a functioning machine capable of performing the operations required for jet engine blade finishing. Task three calls for implementing the feedforward controller developed in the first phase of research. Task four focuses on experimentally measuring system performance and optimizing the controller design. Task five activity will test the system developed in the previous tasks and assess its ability to perform the finishing operations on aircraft turbine engine blades. Task six extends the system testing to other types of parts. Task seven examines another platform modification which involves the use of piezoelectric elements to achieve high precision, high frequency motion. The intent is to follow up phase two work with a phase three effort oriented toward producing commercial versions of the system developed in phase two. The impact of this work will be on the machine tool industry where innovative concepts which can reduce costs and improve quality are clearly needed.