| Summary: | 碩士 === 國立中興大學 === 機械工程學系所 === 100 === In recent years, Taiwan’s machine tool industry is moving toward high speed and practical. In order to enhance the international competitiveness of Taiwan’s machine tool industry, we must research and development the key technologies and components of the localization and low-cost. In addition to the technology in manufacturing, measurement, fabricate, error measurement and compensation, and control system, design and development process of machine tool is also important. If it replaced certain testing and tuning in development and design process with computer-aided simulation, not only can reduce the cost of hardware test, but also the period of production, and thus achieve the purpose of improving competitiveness.
The feed drive system composed of linear-guide system and ball-screw system is the most important part of the impact of the dynamic characteristics of the machine tool. Focus on single-axis feed drive motion, we use multi-body dynamics with method of finite element to analyze the dynamic model, and compare the differences with different conditions. Before the simulation, we must simplify the model first, and compare differences of natural frequency and mode shape using modal analysis. In rigid and flexible dynamic model, stiffness is a very important parameter. In this paper, we calculate the contact stiffness between a nut and screw by Hertizan contact stress. And boundary conditions of base are set by Bushing Force which is defined as frame foundation’s static stiffness.
Because screw stiffness are difference between the screw ends and the middle, so moving plate’s motion will be difference due to different starting potions. Due to the effect of inertia, Fast feed rate caused more overshoot error. After adding control system, the position, velocity, acceleration of the model could have a huge impact because of the control parameters and characteristics of servo motor. Wrong parameter could cause wrong analysis, so applicable parameter must be found first. And then servo control system can be analyzed.
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