RRT-Assisted Pseudo-Rigid Formation Design

• Main Authors: Shen-Lin Peng, 彭聖霖
• Other Authors: Li-Shen Wang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/18586311916776178081

碩士 === 臺灣大學 === 應用力學研究所 === 98 === The main purpose of this research is to develop a path planning scheme for multi-vehicle systems, which can produce collision-free paths for the vehicles in the system by changing the formation of system. We apply the pseudo-rigid body theory to the formation design. The formation of system can be determined by a homogenous deformation tensor. Such concept is called the Pseudo-Rigid Formation (PRF). PRF are allowed to rotate, stretch, shear and the combinations of the previous three types of deformation. Comparing with rigid body formation, PRF can adapt to the environments more easily during path planning, and PRF also has a good ability of maintaining the uniformity of system. Another feature of our approach is that it allows to add/remove other vehicles into/from the formation gracefully. And the number of vehicles in the system will not affect the complexity of calculating the deformation tensor. In order to obtain a smooth path for the center of formation and reserve enough space for the formation design, the method of Rapidly-exploring Random Tree (RRT) is used along with some path-smoothing algorithms and potential field methods. The concept of virtual obstacles is introduced to deal with the limitations of the capability of the vehicles in tracing the curved paths. A few design criteria are then adopted to find the suitable PRF. Our approach can be used in many environments without the problem of trapping in local minimum. The design examples show that the proposed scheme is feasible and effective.