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August 29, 2015 14:21
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Some vanilla RRT code in MATLAB (mostly to see how slow MATLAB is...)
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| function[] = RRT() | |
| clear all;clc; clf; | |
| tree = []; | |
| buildRRT(); | |
| %plot(tree.x,tree.y,'ro-'); | |
| %plot_tree(tree) | |
| function [] = plotTree(tree) | |
| for i=1:length(tree), | |
| n = tree(1); | |
| np = n.parent; | |
| if np ~= inf | |
| plot([np.x, np.y], [n.x, n.y], 'r.-'); | |
| end | |
| end | |
| function[] = buildRRT() | |
| global tree; | |
| x0=0; y0=0; xGoal=5; yGoal=5; | |
| node.x=x0; node.y=y0; node.parent=0; | |
| epsilon=1; | |
| tree = [tree, node]; | |
| while(norm([node.x-xGoal,node.y-yGoal]) > epsilon) | |
| nodeidx = randi([1, length(tree)]); | |
| node = generateSample( tree(nodeidx)); | |
| node.parent=inf; | |
| node = nearestVertex(node); | |
| % plot(node.x,node.y,'ro-'); hold on; axis([-10 10 -10 10]); pause(0.1); | |
| fprintf('id: %d, (%.2f, %.2f) p: %d\n', length(tree), node.x, node.y, node.parent); | |
| plot([node.x, tree(node.parent).x], [node.y, tree(node.parent).y], 'r.-'); | |
| hold on; axis([-10 10 -10 10]); | |
| pause(0.1); | |
| end | |
| function[node] = nearestVertex(node) | |
| global tree; | |
| n=length(tree); d = zeros(n,1); | |
| dmin=1000; index=0; | |
| for i=1:n | |
| d(i) = norm([tree(i).x-node.x, tree(i).y-node.y]); | |
| if d(i)<dmin | |
| dmin=d(i); | |
| index=i; | |
| end | |
| end | |
| node.parent=index; | |
| tree = [tree, node]; | |
| function[s_new] = generateSample(s0) | |
| % for a system given by dynamics | |
| % \dot x = u, \dot y = v, |u|,|v| <1 | |
| dt=1; % time step | |
| u = -1 + 2*rand(1); % uniform random number between -1 to 1 | |
| v = -1 + 2*rand(1); | |
| s_new.x = s0.x + u*dt; % new sample | |
| s_new.y = s0.y + v*dt; | |
| if collisionCheck(s_new) | |
| s_new = generateSample(s0); | |
| end | |
| function [inCollision] = collisionCheck(s_new) | |
| r_obst = 0.2; | |
| x_obst = 2.5; | |
| y_obst = 2.5; | |
| if norm([x_obst-s_new.x,y_obst-s_new.y])<r_obst | |
| inCollision = 1; | |
| else | |
| inCollision = 0; | |
| end |
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