路径规划—PRM(Probabilistic Road Map)

一、原理：

Probabilistic Road Map, 分为两个过程

Learning phase和Query phase.

Learning phase:

1. Sample N points in C-space.（在空间内撒N个点）

2. Delete points that are not collision-free.

3. Connect to nearest points and get collision-free segments.

4. Delete segments that are not collision free.

Query phase:

1. Search on the road map to find a path from the start to the goal(using Dijkstra's algorithm or the A* algorithm).
2. Road map is now similar with the grid map(or a simplified grid map).

二、优缺点：

优势：

概率完备；不用在整个环境搜索，简化了环境，相对于A*更加高效

劣势：

Required to solve 2 point boundary value problem.

Build graph over state space but no particular focus on generating a path.

Not efficient.

改进方法：Lazy collision-checking

一、基本思想：

Collision-checking process is time-consuming, especially in complex or high-dimensional environments. So sample points and generates segments without considering the collision.

二、流程：

1. Find a path on the road map generated without collision-checking.

2. Delete the corresponding edges and nodes if the path is not collision free.

3. Restart path finding.

标签：Map,map,PRM,free,collision,points,phase,path,Probabilistic
来源： https://www.cnblogs.com/zhjblogs/p/15063108.html