Search

Aircraft panel automatic drilling and riveting system is the key equipment to realize aircraft panel assembly with high efficiency and quality. In practical application, automatic drilling and riveting system should bear cyclic riveting force with large load, which means such systems must have enough stiffness to deal with this situation. The stiffness of each components in automatic drilling and riveting system reflects as the end stiffness finally; in the meanwhile, end stiffness and riveting ability of the system will be affected when the posture of the system changes. According to this situation, stiffness matrixes related to mechanics characteristic of motion axes, transmission parts, inner-side working head, and outer-side working head of automatic horizontal dual-machine cooperative drilling and riveting system are established, in which the Jacobi matrix method, point transformation matrix method, and finite element analysis are applied. Finally, the static end stiffness model is proposed based on multi-body small deflection theory. The end stiffness model has been validated through experimental measurement, and the stiffness relationship of dual-machine tool system was obtained, which applied important data for structure optimization and control system design. [ABSTRACT FROM AUTHOR]

To determine the error compensation for cutting forces with a machine tool, this paper proposes a comprehensive error compensation method that determines an equivalent cutting force. The loading system that applies this equivalent cutting force was designed to load a constant force that imitates the actual cutting force of a machine tool. The equivalent cutting force, when applied to the working table of the machine tool, induces an error that can be directly measured by a laser interferometer. Moreover, a stable measurement environment suitable for laser interferometer is configured. A comprehensive error compensation model of a three-axis computer numerical control (CNC) machine tool was developed using multi-body systems theory and homogeneous transformation matrices. Solutions for the error compensation model and parametric equation were automatically found using MATLAB, based on this model. The effectiveness of this compensation method has been confirmed by machining experiments. The experimental results show that this comprehensive error compensation of the equivalent cutting force can greatly improve machining accuracy. [ABSTRACT FROM AUTHOR]

The five-axis machine tools are increasingly popular for meeting the demand of machining the workpiece with growing geometric complexity and high accuracy. This paper studies the volumetric error modeling and its sensitivity analysis for the purpose of machine design. The volumetric error model of a five-axis machine tool with the configuration of RTTTR is established based on rigid body kinematics and homogeneous transformation matrix, in which 37 error components are involved. The sensitivity analysis of volumetric error regarding 37 error components is carried out respectively. The analysis results are successfully used for the accuracy design and manufacture of a five-axis ultra-precision machine tool. The preliminary experiment of machining sine grid surface testifies the high accuracy and effectiveness of the designed five-axis machine tool. [ABSTRACT FROM AUTHOR]