Research On Virtual NC System Used In Automatic Fiber Placement

Automated Fiber Placement technology is a key technology that realizes automated placement molding of fiber composites, which can effectively reduce manufacturing costs of composite products, and improve efficiency and quality to promote widespread use of fiber composites. To order to achieve this goal, it not only need the support of hardware devices, but also software systems. With the development of information technology, virtual manufacturing technology has been applied to various manufacturing processes. Similarly, automated fiber placement is also linked closely with virtual manufacturing technology.The main research focus of this thesis is virtual NC system of fiber placement,which can provide validation support for trajectory planning theory of automatic fiber placement. The main contents are as follows:1. Mechanical structure model of fiber placement machines is established in virtual environments. The system selects the gantry placement machine as a prototype, and determines the movement form and the overall structure of the placement machine by analyzing its movement coordinate fiber placement requires. In three-dimensional software,a simplified model of fiber placement machine is designed, and is exported to the other format.Finally, the machine model is drawn by OpenGL in VC ++ based on the data interpreting from the format file, while motion axis of fiber placement machine is defined in this environment.2. The virtual CNC system unit is designed by researching NC theory, including the NC code interpretation, acceleration/deceleration processing and interpolation operation. In this unit, the NC code interpreter module can examine the NC code and extract placement information and store the data. Acceleration/deceleration processing module can control the speed in the S-curve way, and make the velocity change smoothly. Interpolation operation module can generate the data driving the fiber placement machine model by a linear interpolation way.3. The dynamic simulation of automated fiber placement process is achieved, which can reflect the effect of the fiber placement. To show the fiber tow, it needs to calculate the trajectory by machine pose state at each time, and then extend the half width of the fiber tow to get the extended points, which can be used to draw triangular facets to represent fiber tow. In the adjustment of the placement boots, the effect can be realized by redrawing the placement boots in changing location. Besides, it can achieve the effect of adding and cutting fiber tow by setting the placement flag to decide if the fiber tow is fed.4. Based on VC ++ platform, the entire software interface is built, which is divided into three regions: the graphical display, NC panel and code display. It can finish dynamic display of fiber placement process, code display, operation status display and parameter setting,which realize the human-computer interaction function.This thesis establishes virtual CNC system of fiber placement,including the import of NC code, acceleration/deceleration control, interpolation operation, and finally complete the effect of dynamic display of fiber placement. It can provide support for the verification of trajectory planning theory of automatic fiber placement.