rrt算法python代码
时间: 2023-08-29 19:11:26 浏览: 69
以下是一个简单的RRT算法的Python实现:
```python
import math
import random
class Node:
def __init__(self, x, y):
self.x = x
self.y = y
self.parent = None
class RRT:
def __init__(self, start, goal, obstacles, step_size, max_iter):
self.start = Node(start[0], start[1])
self.goal = Node(goal[0], goal[1])
self.obstacles = obstacles
self.step_size = step_size
self.max_iter = max_iter
self.nodes = [self.start]
def generate(self):
for i in range(self.max_iter):
q_rand = self.get_random_node()
q_near = self.get_nearest_node(q_rand)
q_new = self.step(q_near, q_rand)
if self.check_collision(q_near, q_new):
self.nodes.append(q_new)
q_new.parent = q_near
if self.check_goal(q_new):
return self.get_path(q_new)
return None
def get_random_node(self):
if random.randint(0, 100) > 10:
return Node(random.uniform(0, 10), random.uniform(0, 10))
else:
return self.goal
def get_nearest_node(self, q_rand):
distances = [(node.x - q_rand.x) ** 2 + (node.y - q_rand.y) ** 2 for node in self.nodes]
nearest_node_index = distances.index(min(distances))
return self.nodes[nearest_node_index]
def step(self, q_near, q_rand):
theta = math.atan2(q_rand.y - q_near.y, q_rand.x - q_near.x)
x = q_near.x + self.step_size * math.cos(theta)
y = q_near.y + self.step_size * math.sin(theta)
return Node(x, y)
def check_collision(self, q_near, q_new):
for obstacle in self.obstacles:
if self.intersects(obstacle[0], obstacle[1], q_near, q_new):
return False
return True
def intersects(self, a, b, q1, q2):
def ccw(a, b, c):
return (c.y-a.y) * (b.x-a.x) > (b.y-a.y) * (c.x-a.x)
return ccw(a,q1,q2) != ccw(b,q1,q2) and ccw(a,b,q1) != ccw(a,b,q2)
def check_goal(self, q_new):
return math.sqrt((q_new.x - self.goal.x) ** 2 + (q_new.y - self.goal.y) ** 2) < self.step_size
def get_path(self, q_new):
path = []
node = q_new
while node is not None:
path.append((node.x, node.y))
node = node.parent
return path[::-1]
```
在此实现中,节点表示在地图上的点。RRT类初始化需要起点、终点、障碍物、步长和最大迭代次数。generate()方法使用RRT算法生成路径,如果找到路径,则返回路径。如果没有找到路径,则返回None。
get_random_node()方法生成随机节点,如果随机数小于90,则生成一个随机节点,否则生成目标节点。get_nearest_node()方法找到离随机节点最近的节点。step()方法生成从最近节点到随机节点的新节点。check_collision()方法检查从最近节点到新节点的路径是否与任何障碍物相交。intersects()方法检查两个线段是否相交。check_goal()方法检查新节点是否在目标节点附近。如果是,则返回True。get_path()方法返回路径。