direction vector

例句：

1. 1. The car's steeringwheel is pointing in the direction of theroad.
   汽车的方向盘指向道路的方向。
2. 2. Themap shows the direction vector from the citycenter to the beach.
   地图显示了从市中心到海滩的方向向量。
3. 3. Therobot can follow the directionvector and move towards the target.
   机器人可以跟随方向向量并朝目标移动。