Files
PathPlanning/Sampling-based Planning/rrt_2D/informed_rrt_star.py
T
zhm-real ffa911e80c update
2020-07-28 00:48:51 -07:00

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6.4 KiB
Python

"""
INFORMED_RRT_STAR 2D
@author: huiming zhou
"""
import os
import sys
import math
import random
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as patches
sys.path.append(os.path.dirname(os.path.abspath(__file__)) +
"/../../Sampling-based Planning/")
from rrt_2D import env
from rrt_2D import plotting
from rrt_2D import utils
from rrt_2D import queue
class Node:
def __init__(self, n):
self.x = n[0]
self.y = n[1]
self.parent = None
class IRrtStar:
def __init__(self, x_start, x_goal, step_len,
goal_sample_rate, search_radius, iter_max):
self.x_start = Node(x_start)
self.x_goal = Node(x_goal)
self.step_len = step_len
self.goal_sample_rate = goal_sample_rate
self.search_radius = search_radius
self.iter_max = iter_max
self.env = env.Env()
self.plotting = plotting.Plotting(x_start, x_goal)
self.utils = utils.Utils()
# self.fig, self.ax = plt.subplots()
self.x_range = self.env.x_range
self.y_range = self.env.y_range
self.obs_circle = self.env.obs_circle
self.obs_rectangle = self.env.obs_rectangle
self.obs_boundary = self.env.obs_boundary
self.V = [self.x_start]
self.X_soln = set()
self.path = None
def planning(self):
c_best = np.inf
c_min = self.Line(self.x_start, self.x_goal)
x_center = np.array([[(self.x_start.x + self.x_goal.x) / 2.0],
[(self.x_start.y + self.x_goal.y) / 2.0], [0.0]])
a1 = np.array([[(self.x_goal.x - self.x_start.x) / c_min],
[(self.x_goal.y - self.x_start.y) / c_min], [0.0]])
e_theta = math.atan2(a1[1], a1[0])
id1_t = np.array([[1.0, 0.0, 0.0]])
M = a1 @ id1_t
U, S, Vh = np.linalg.svd(M, True, True)
C = np.dot(np.dot(U, np.diag(
[1.0, 1.0, np.linalg.det(U) * np.linalg.det(np.transpose(Vh))])), Vh)
for k in range(self.iter_max):
if k % 500 == 0:
print(k)
if self.X_soln:
c_best = min([self.Cost(x) for x in self.X_soln])
x_rand = self.Sample(self.x_start, self.x_goal, c_best, x_center, C)
x_nearest = self.Nearest(self.V, x_rand)
x_new = self.Steer(x_nearest, x_rand)
if x_new and not self.utils.is_collision(x_nearest, x_new):
self.V.append(x_new)
X_near = self.Near(self.V, x_new)
x_min = x_nearest
c_min = self.Cost(x_min) + self.Line(x_nearest, x_new)
for x_near in X_near:
c_new = self.Cost(x_near) + self.Line(x_near, x_new)
if c_new < c_min:
x_new.parent = x_near
c_min = c_new
for x_near in X_near:
c_near = self.Cost(x_near)
c_new = self.Cost(x_new) + self.Line(x_new, x_near)
if c_new < c_near:
x_near.parent = x_new
if self.InGoalRegion(x_new):
self.X_soln.add(x_new)
path = self.ExtractPath(self.V[-1])
self.plotting.animation(self.V, path, "Informed rrt*")
def ExtractPath(self, node):
path = [[self.x_goal.x, self.x_goal.y]]
while node.parent:
path.append([node.x, node.y])
node = node.parent
path.append([self.x_start.x, self.x_start.y])
return path
def InGoalRegion(self, node):
if self.Line(node, self.x_goal) < self.step_len:
return True
return False
def Steer(self, x_start, x_goal):
dist, theta = self.get_distance_and_angle(x_start, x_goal)
dist = min(self.step_len, dist)
node_new = Node((x_start.x + dist * math.cos(theta),
x_start.y + dist * math.sin(theta)))
node_new.parent = x_start
return node_new
def Near(self, nodelist, node):
n = len(nodelist) + 1
r = 2 * self.search_radius * math.sqrt((math.log(n) / n))
dist_table = [math.hypot(nd.x - node.x, nd.y - node.y) for nd in nodelist]
X_near = [nodelist[ind] for ind in range(len(dist_table)) if dist_table[ind] <= r and
not self.utils.is_collision(node, nodelist[ind])]
return X_near
def Sample(self, x_start, x_goal, c_max, x_center, C):
if c_max < np.inf:
c_min = self.Line(x_start, x_goal)
r = [c_max / 2.0,
math.sqrt(c_max ** 2 - c_min ** 2) / 2.0,
math.sqrt(c_max ** 2 - c_min ** 2) / 2.0]
L = np.diag(r)
x_ball = self.SampleUnitNBall()
x_rand = np.dot(np.dot(C, L), x_ball) + x_center
else:
x_rand = self.SampleFreeSpace()
return x_rand
def SampleFreeSpace(self):
delta = self.utils.delta
if np.random.random() > self.goal_sample_rate:
return [np.random.uniform(self.x_range[0] + delta, self.x_range[1] - delta),
np.random.uniform(self.y_range[0] + delta, self.y_range[1] - delta)]
return [self.x_goal.x, self.x_goal.y]
@staticmethod
def SampleUnitNBall():
x, y = random.random(), random.random()
if y < x:
x, y = y, x
sample = np.array([[y * math.cos(2 * math.pi * x / y)],
[y * math.sin(2 * math.pi * x / y)], [0.0]])
return sample
@staticmethod
def Nearest(nodelist, n):
return nodelist[int(np.argmin([math.hypot(nd.x - n.x, nd.y - n.y)
for nd in nodelist]))]
@staticmethod
def Line(x_start, x_goal):
return math.hypot(x_goal.x - x_start.x, x_goal.y - x_start.y)
@staticmethod
def Cost(node_p):
node = node_p
cost = 0.0
while node.parent:
cost += math.hypot(node.x - node.parent.x, node.y - node.parent.y)
node = node.parent
return cost
@staticmethod
def get_distance_and_angle(node_start, node_end):
dx = node_end.x - node_start.x
dy = node_end.y - node_start.y
return math.hypot(dx, dy), math.atan2(dy, dx)
def main():
x_start = (2, 2) # Starting node
x_goal = (49, 24) # Goal node
rrt_star = IRrtStar(x_start, x_goal, 10, 0.10, 20, 4000)
rrt_star.planning()
if __name__ == '__main__':
main()