Structural Dynamic Characteristics Analysis and Vibration Control of Precision External Grinder

  • Cha, Kuo-Chiang (PI)

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details

Abstract

With the development of production technique, grinding plays the increasingly important role in mechanical processing. Among advanced industrial countries, the annual yields of grinders has trended exceed the annual yields of lathe machines. At present, the research focus of high speed grinding with intelligent functions has inclined to the development of static and dynamic pressure with components adopted from static hydraulic pressure bearings, air bearings and magnetic bearings, together with other components like static-and-dynamic guides, linear guides and linear motors, etc. To reach the requirement for spindles, guides and feed mechanisms with high speed and excellent precision, other machine designs shall required for excellent performances like anti-vibration and stability under various cutting parameters. Therefore, if theoretically, it is available to create the whole-machine dynamic model and predict dynamic performance, and the try-and-error effort can be reduced. It is significantly important to enhance whole-machine dynamic performance, computing efficiency and cost-down. This research project is prepared in response to the 2-year plan prompted by National Science Council focusing on precision external grinders. It is mainly aimed to create the practical whole-machine dynamic model with lumped mass parameter units and interface units, together with experimental validation and comparison. The model compliance and energy distribution are adopted as theory foundation of structure dynamic design and analysis is implemented to improve the weakness of technique researches like the whole-machine structure and vibration control. Within this research, there are two different surrogate model analysis skills used to find the system design parameters and the optimal design parameters after additional installation of an absorber. Therefore, the practically applicable analysis software can be developed; meanwhile, the test is practically implemented or the features of stiffness and damping of interface parts of whole-machine are gathered. The applicable analysis database is created thereafter. After the plan is done, the data can be served to grinding process practitioners with the important reference of analysis and design evaluation available for preliminary stages. The 1st year of this plan: the Lagrange energy method is firstly adopted to deduce lumped parameter dynamic models of precision external grinders. It is aimed to determine the inertia energy distribution rate for every sub-structure, the elastic energy distribution rate for sub-structure interface and the model compliance between the tool and work piece under various resonance frequencies to reach sufficiently representative factors with significant influence on system dynamic performance. The Response Surface Methodology (RSM) and Back Propagation Neural Network (BPNN) are also separately used to construct two types of surrogate models for structural dynamic performance to make comparison of predicting capabilities and their variance. Finally, optimization analysis can be implemented to reach the optimal parameters of system structure and the testing technique potentials for initial components are built simultaneously. The 2nd year of this plan: It is aimed to explore the issue of vibration control under the whole-machine cutting. Firstly, in view of energy, the locations most suitably to install with an absorber can be found and the system dynamic equations for the whole-machine additionally equipped with an absorber can be also well deduced. It is aimed to determine optimal design parameters and locations of an absorber. Finally, the analysis and experimental comparison are implemented on similar machine tools and overall research results are well summarized thereafter.

Project IDs

Project ID:PB9611-0536
External Project ID:NSC96-2221-E182-063
StatusFinished
Effective start/end date01/08/0731/07/08

Keywords

  • Precision External Grinder, Response Surface Methodology, BackPropagation Neural Network, Surrogate Model, Modal Compliance,Dynamic Absorber, Optimization Analysis

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