基于栅格地图的改进RRT算法matlab代码实现
时间: 2023-10-04 13:07:29 浏览: 302
以下是基于栅格地图的改进RRT算法的MATLAB代码实现。其中,栅格地图是一个二维数组,0表示障碍物,1表示可通行的区域。
```
function [path,tree] = rrt_star(map,start,goal,max_iter,delta,max_dist)
% map: 二维栅格地图,0表示障碍物,1表示可通行的区域
% start: 起点坐标
% goal: 终点坐标
% max_iter: 最大迭代次数
% delta: 每次迭代的步长
% max_dist: 搜索半径
% 初始化树
tree(1).coord = start;
tree(1).parent = 0;
tree(1).cost = 0;
% 初始化路径
path = [];
for i = 1:max_iter
% 生成随机点
if rand < 0.5
% 50%的概率选择终点
rand_point = goal;
else
% 50%的概率在地图内随机选择一个点
rand_point = [randi(size(map,1)),randi(size(map,2))];
end
% 找到最近的点
dist = pdist2([tree.coord],rand_point);
[min_dist,min_idx] = min(dist);
nearest_node = tree(min_idx);
% 计算新节点坐标
new_coord = steer(nearest_node.coord,rand_point,delta);
% 判断新节点是否在地图内
if ~inside_map(new_coord,map)
continue;
end
% 判断新节点与最近节点之间是否有障碍物
if obstacle_free(nearest_node.coord,new_coord,map)
% 在最近节点的邻居中选择最优的父节点
near_nodes = find_near_nodes(tree,new_coord,max_dist);
min_cost = nearest_node.cost + distance(nearest_node.coord,new_coord);
min_node = [];
for j = 1:length(near_nodes)
if obstacle_free(near_nodes(j).coord,new_coord,map)
cost = near_nodes(j).cost + distance(near_nodes(j).coord,new_coord);
if cost < min_cost
min_cost = cost;
min_node = near_nodes(j);
end
end
end
% 添加新节点
new_node.coord = new_coord;
new_node.parent = min_node;
new_node.cost = min_cost;
tree(end+1) = new_node;
% 更新邻居节点的父节点
for j = 1:length(near_nodes)
if obstacle_free(new_coord,near_nodes(j).coord,map) && ...
new_node.cost + distance(new_coord,near_nodes(j).coord) < near_nodes(j).cost
near_nodes(j).parent = length(tree);
end
end
end
% 判断是否到达终点
if distance(new_coord,goal) < delta
path = find_path(tree,length(tree));
break;
end
end
if isempty(path)
% 未找到路径
return;
end
% 可视化路径和树
figure;
plot_path(path,map);
hold on;
plot_tree(tree,map);
end
% 路径可视化
function plot_path(path,map)
path_length = size(path,1);
for i = 2:path_length
plot([path(i-1,2),path(i,2)],[path(i-1,1),path(i,1)],'r','LineWidth',2);
end
axis([1,size(map,2),1,size(map,1)]);
end
% 树可视化
function plot_tree(tree,map)
for i = 2:length(tree)
plot([tree(i).coord(2),tree(tree(i).parent).coord(2)],...
[tree(i).coord(1),tree(tree(i).parent).coord(1)],'b','LineWidth',1);
end
end
% 找到起点到终点的路径
function path = find_path(tree,idx)
path = [];
while idx ~= 0
path = [tree(idx).coord;path];
idx = tree(idx).parent;
end
end
% 计算两点间距离
function dist = distance(p1,p2)
dist = norm(p1 - p2);
end
% 判断点是否在地图内
function inside = inside_map(coord,map)
inside = coord(1) >= 1 && coord(1) <= size(map,1) && ...
coord(2) >= 1 && coord(2) <= size(map,2) && ...
map(coord(1),coord(2)) == 1;
end
% 判断两点之间是否有障碍物
function free = obstacle_free(p1,p2,map)
free = true;
dist = distance(p1,p2);
n = ceil(dist);
for i = 1:n
t = i / n;
coord = round((1-t)*p1 + t*p2);
if ~inside_map(coord,map) || map(coord(1),coord(2)) == 0
free = false;
break;
end
end
end
% 在最近节点的邻居中找到距离新节点最近的父节点
function near_nodes = find_near_nodes(tree,new_coord,max_dist)
near_nodes = [];
for i = 1:length(tree)
if distance(tree(i).coord,new_coord) <= max_dist
near_nodes = [near_nodes,tree(i)];
end
end
end
% 计算新节点的坐标
function new_coord = steer(from,to,delta)
if distance(from,to) <= delta
new_coord = to;
else
new_coord = from + delta * (to - from) / distance(from,to);
end
end
```