Focusing on the problems such as too many expansion nodes path redundancy points in path planning for the classical A* algorithm
this paper aims to study the improvement of the classical A* algorithm. Firstly
the concept of slant-eight-neighborhood expansion is proposed
and by combining with the four-neighborhood expansion
a novel dual-neighborhood selection expansion strategy is proposed. By this novel strategy
the number of expansion nodes can be greatly reduced in the path search process. In addition
a new heuristic function is established to adapt to a variety of map environments. Hence
the number of expanded nodes can be reduced by above 50% in the same map environment comparing with the classical A* algorithm
and the path search speed can be improved by one order of magnitude
and the efficiency of the algorithm is significantly improved. Then
the initial path is further optimized by establishing a redundant point elimination strategy and the cubic B-spline curve. Thus
an optimal path that meets the robot motion can be obtained by eliminating the redundant nodes and reducing path turns. Finally
the improved A* algorithm is evaluated and analyzed by comparing with the Dijkstra algorithm
four-neighborhood expansion algorithm and eight-neighborhood expansion algorithm by simulation in four maps with different obstacles. And
also the present algorithm is verified by using the field tests based on the intelligent vehicle platform. The results show that by the improved A* algorithm the path search efficiency can improved significantly
the planned path is more suitable for the robot motion. In summary
the present improved A* algorithm is believed to be feasible and effective.