Free-form Surface-contact Measurement Method And Prototype System Development,

The products in the modern manufacturing have such two kinds of different representations as in information model and real model, while the most innovative and valuable part of the manufacturing is included in the former one. This is the case especially for the free-form surface parts widely used in modern industry. Thus such research work as the measuring, modeling, manufacturing and quality assessment of freeform surface parts is of great importance in modern manufacturing industry. In this dissertation, based on the survey of the present research situation and development trends at home and abroad of the free-form surface measurement methods, path planning, collision checking and avoiding, data processing, etc., by absorbing techniques of mechanics, measuring, CAD/CAM and computer control, etc., a contact measure prototype system based on open motion control card was developed, meanwhile the relevant problems on contact measuring were profoundly studied.In Chapter 1, the current study situation of measuring methods for free-form surface, path planning for contact measurement, collision checking and avoiding and the measure data processing is summarized and the problems on contact measurement are also pointed out. Then the main research work of the dissertation is made certain.In Chapter 2, the gross design including hardware structure and software for the contact measure system is brought forward, according to the function requirement analysis of the contact measure system.In Chapter 3, the problem about path planning of contact measure is studied. Triangle mesh method for the surface whose CAD model is unknown is brought forward to fulfill the self-adaptive distributing of measure dots, and the method is proved to be valid by simulated experiment. Then the path generating for contact measure and the methods to optimize it are discussed.In Chapter 4, the collision avoidance problem is discussed in the situation that the CAD model is known and there are two methods that can resolve the problem to some extend. The method of "generate-test" is often used in the situation that the CAD model is unknown, and some collisions that are frequently happened are discussed.In Chapter 5, the method of processing yawp and wrong data is introduced. Then arithmetic to compensating the probe radius error is discussed in detail. After that, the measure data is converted to IGES format in order for the subsequent processing.In Chapter 6, the fulfillment of the contact measure system, some several key technologies for the development and the main software function modules are introduced. Then some main factors that impact on the precision of the contact measure system are analyzed and some experiments are studied.In Chapter 7, the main conclusions of the dissertation are summarized, and the author's ideas about the future work of the contact measure system are proposed.