Efficient and accurate path planning algorithm of unmanned vehicles for unstructured road is of great significant for field disaster relief. An improved A–star algorithm for unmanned vehicle path planning is proposed in this paper to achieve optimized path with shorter length and less inflection point. Redundant safety spaces are set up in the improved algorithm to filter out impassable narrow roads and to avoid collisions between vehicles without obstacles. The prejudgment planning strategy and redundant inflection point elimination strategy are integrated into the algorithm to obtain a better driving path. Furthermore, a safe corridor approach was used in the trajectory optimization to avoid repeated checks and corrections and save computer time. The simulation results show that the path planned with the improved algorithm has shorter length, less inflection point and smoother than the path planned with the initial algorithm, and can avoid collision between vehicle contours and obstacles.

In this paper, an enhanced VARTM process is proposed and its pressure effect on resin infusion behavior and composite material performance is studied to reveal the control mechanism of the fiber volume fraction and void content. The molding is vacuumized during the resin injection stage while it is pressurized during the mold filling and curing stages via a VARTM pressure control system designed in this paper. Theoretical calculations and simulation methods are used to reveal the resin’s in-plane, transverse, and three-dimensional flow patterns in multi-layer media. For typical thin-walled components, the infiltration behavior of resin in isotropic porous media is studied, elucidating the control mechanisms of fiber volume fraction and void content. The experiments demonstrate that the enhanced VARTM process significantly improves mold filling efficiency and composite’s performance. Compared to the regular VARTM process, the panel thickness is reduced by 4% from 1.7 mm, the average tensile strength is increased by 7.3% to 760 MPa, the average flexural strength remains at approximately 720 MPa, porosity is decreased from 1.5% to below 1%, and the fiber volume fraction is increased from 55% to 62%.