Coverage path planning on a complex free-form surface is a representative problem that has been steadily investigated in path planning and automatic control. However, most methods do not consider many optimisation conditions and cannot deal with complex surfaces, closed surfaces, and the intersection of multiple surfaces. In this study, a novel and efficient coverage path-planning method is proposed that considers trajectory optimisation information and uses point cloud data for environmental modelling. First, the point cloud data are denoised and simplified. Then, the path points are converted into the rotation angle of each joint of the manipulator. A mathematical model dedicated to energy consumption, processing time, and path smoothness as optimisation objectives is developed, and an improved ant colony algorithm is used to solve this problem. Two measures are proposed to prevent the algorithm from being trapped in a local optimum, thereby improving the global search ability of the algorithm. The standard test results indicate that the improved algorithm performs better than the ant colony algorithm and the max–min ant system. The numerical simulation results reveal that compared with the point cloud slicing technique, the proposed method can obtain a more efficient path. The laser ablation de-rusting experiment results specify the utility of the proposed approach.
An efficient iterative hybrid multilevel fast multipole algorithm (MLFMA) and the physical optics (PO) is presented to efficiently analyze the large size antenna mounted on the electrically large platform, in which, the MLFMA is used to accelerate the impedance matrix–vector multiply procedure of method of moment (MoM) and the PO is employed to simulate the large platform. In this hybrid scheme, to overcome the computational cost required in the evaluation of the electrically large PO region contribution to the MLFMA region, the strategy of the efficient iterative MoM‐PO (EI‐MoM‐PO) is employed. In addition, the electrically large PO region shadowing effect coefficient will be checked before the computation of PO current, then the coefficient will be stored in bit format by using the Bitmap index method which is general enough to reduce the CPU time and memory consumption. The combination of EI‐MLFMA‐PO and Bitmap assists us to construct a proposed method that can reduce the computation cost dramatically and obtain good accuracy. Several examples are demonstrated to validate and prove the accuracy and efficiency of our method compared with the hybrid MLFMA‐PO method in FEKO.
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