|关键词||工艺约束 路径评价 路径规划 复合材料 自动丝束铺放|
|其他摘要|| Automated Fibre Placement (AFP) has many advantages such as high processing efficiency, low manufacturing cost, good repeatability and high level of automation, and it has been widely used in the manufacturing of various large and complex composite parts in developed countries, but the research of the AFP is still in the initial stage in our country. Path planning is one of the key technologies to achieve the automated placement molding of composites, in-depth study of this technology is conducive to the AFP development of our country. In this thesis, path planning for AFP of complicated surface structure is studied, which mainly involves the problems such as handling the process constraint of placement ability, coverage and directionality, comprehensive evaluation of path. The main work and contributions of this paper are as follows:|
(1) The relationship between the placement ability and the curvature of the tow steering is analyzed, and a constraint processing algorithm based on iterative modification of placement angle and series limit for the placement ability is proposed.
Firstly, the influence of path’s steering radius on the lateral defo the placement ability rmation of the tow is analyzed, and the lateral bending placement experiments are conducted with the minimum steering radius of the tow under different layup pressure and layup temperature being acquired. Secondly, a constraint processing algorithm based on iterative modification of placement angle and series limit for the steering curvature of the tow is proposed, which is on the basis of the existing algorithm. Lastly, a simulation experiment of the tow path’s placement ability based on the above constraint processing algorithm is carried out, the result verifies the effectiveness of the constraint processing algorithm for the placement ability.
(2) A method for optimizing the path coverage based on the dynamic adjustment of the position of the tow cutting and restarting is proposed. Firstly, the fibre overlap and gap in various situations are analyzed, including the formation reason and the calculation method of the tow coverage area. Secondly, a strategy where the position of the tow cutting and restarting is dynamically adjusted is proposed, for the purpose of minimizing the area of fibre overlap and gap. Lastly, a series of simulation experiments are conducted to verify the effectiveness of the proposed optimization method.
(3) A path planning algorithm that integrates process constraints and path evaluation is proposed, and path optimization is studied. Firstly, two constraint processing methods for the tow directionality are proposed: the constant angle with retaining the longest normal path segment method and the parallel-equidistant offsetting with reduced offset distance method. Secondly, a novel path planning algorithm is proposed, it takes the constraints of placement ability, coverage and directionality into account and uses the path local-evaluation strategy based on placement efficiency and quality. The simulation experiments show that the proposed algorithm outperforms the existing path planning algorithm based on the process constraints. Lastly, a global evaluation model and a selection model of tow path are established, it is based on the above path planning algorithm and related to the process requirements. The simulation results indicate that the proposed models can reasonably evaluate the path according to the trade-off between the placement efficiency and quality, and select the optimal fibre path.
|蒋敏. 面向复杂曲面构件的自动铺丝路径规划方法研究[D]. 北京. 中国科学院研究生院,2018.|