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Atsushi Sakai
2019-06-25 21:57:56 +09:00
parent 43a59ae09b
commit e62e5c7c21
1 changed files with 51 additions and 38 deletions
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89
PathPlanning/AStar/a_star.py
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@@ -1,6 +1,6 @@
"""
A* grid based planning
A* grid planning
author: Atsushi Sakai(@Atsushi_twi)
Nikos Kanargias (nkana@tee.gr)
@@ -14,11 +14,12 @@ import math
show_animation = True
class AStarPlanner:
def __init__(self, ox, oy, reso, rr):
"""
Intialize map for a star planning
Initialize grid map for a star planning
ox: x position list of Obstacles [m]
oy: y position list of Obstacles [m]
@@ -61,19 +62,19 @@ class AStarPlanner:
ngoal = self.Node(self.calc_xyindex(gx, self.minx),
self.calc_xyindex(gy, self.miny), 0.0, -1)
openset, closedset = dict(), dict()
openset[self.calc_index(nstart)] = nstart
open_set, closed_set = dict(), dict()
open_set[self.calc_grid_index(nstart)] = nstart
while 1:
c_id = min(
openset, key=lambda o: openset[o].cost + self.calc_heuristic(ngoal, openset[o]))
current = openset[c_id]
open_set, key=lambda o: open_set[o].cost + self.calc_heuristic(ngoal, open_set[o]))
current = open_set[c_id]
# show graph
if show_animation: # pragma: no cover
plt.plot(self.calc_position(current.x, self.minx),
self.calc_position(current.y, self.miny), "xc")
if len(closedset.keys()) % 10 == 0:
plt.plot(self.calc_grid_position(current.x, self.minx),
self.calc_grid_position(current.y, self.miny), "xc")
if len(closed_set.keys()) % 10 == 0:
plt.pause(0.001)
if current.x == ngoal.x and current.y == ngoal.y:
@@ -83,66 +84,76 @@ class AStarPlanner:
break
# Remove the item from the open set
del openset[c_id]
del open_set[c_id]
# Add it to the closed set
closedset[c_id] = current
closed_set[c_id] = current
# expand search grid based on motion model
for i, _ in enumerate(self.motion):
node = self.Node(current.x + self.motion[i][0],
current.y + self.motion[i][1],
current.cost + self.motion[i][2], c_id)
n_id = self.calc_index(node)
n_id = self.calc_grid_index(node)
if n_id in closedset:
# If the node is in closed_set, do nothing
if n_id in closed_set:
continue
# If the node is not safe, do nothing
if not self.verify_node(node):
continue
if n_id not in openset:
openset[n_id] = node # Discover a new node
if n_id not in open_set:
open_set[n_id] = node # discovered a new node
else:
if openset[n_id].cost >= node.cost:
# This path is the best until now. record it!
openset[n_id] = node
if open_set[n_id].cost >= node.cost:
# This path is the best until now. record it
open_set[n_id] = node
rx, ry = self.calc_final_path(ngoal, closedset)
rx, ry = self.calc_final_path(ngoal, closed_set)
return rx, ry
def calc_final_path(self, ngoal, closedset):
# generate final course
rx, ry = [self.calc_position(ngoal.x, self.minx)], [
self.calc_position(ngoal.y, self.miny)]
rx, ry = [self.calc_grid_position(ngoal.x, self.minx)], [
self.calc_grid_position(ngoal.y, self.miny)]
pind = ngoal.pind
while pind != -1:
n = closedset[pind]
rx.append(self.calc_position(n.x, self.minx))
ry.append(self.calc_position(n.y, self.miny))
rx.append(self.calc_grid_position(n.x, self.minx))
ry.append(self.calc_grid_position(n.y, self.miny))
pind = n.pind
return rx, ry
def calc_heuristic(self, n1, n2):
@staticmethod
def calc_heuristic(n1, n2):
w = 1.0 # weight of heuristic
d = w * math.sqrt((n1.x - n2.x)**2 + (n1.y - n2.y)**2)
d = w * math.sqrt((n1.x - n2.x) ** 2 + (n1.y - n2.y) ** 2)
return d
def calc_position(self, index, minp):
pos = index*self.reso+minp
def calc_grid_position(self, index, minp):
"""
calc grid position
:param index:
:param minp:
:return:
"""
pos = index * self.reso + minp
return pos
def calc_xyindex(self, position, minp):
return round((position - minp)/self.reso)
def calc_xyindex(self, position, min_pos):
return round((position - min_pos) / self.reso)
def calc_index(self, node):
def calc_grid_index(self, node):
return (node.y - self.miny) * self.xwidth + (node.x - self.minx)
def verify_node(self, node):
px = self.calc_position(node.x, self.minx)
py = self.calc_position(node.y, self.miny)
px = self.calc_grid_position(node.x, self.minx)
py = self.calc_grid_position(node.y, self.miny)
if px < self.minx:
return False
@@ -153,6 +164,7 @@ class AStarPlanner:
elif py >= self.maxy:
return False
# collision check
if self.obmap[node.x][node.y]:
return False
@@ -169,8 +181,8 @@ class AStarPlanner:
print("maxx:", self.maxx)
print("maxy:", self.maxy)
self.xwidth = round((self.maxx - self.minx)/self.reso)
self.ywidth = round((self.maxy - self.miny)/self.reso)
self.xwidth = round((self.maxx - self.minx) / self.reso)
self.ywidth = round((self.maxy - self.miny) / self.reso)
print("xwidth:", self.xwidth)
print("ywidth:", self.ywidth)
@@ -178,16 +190,17 @@ class AStarPlanner:
self.obmap = [[False for i in range(self.ywidth)]
for i in range(self.xwidth)]
for ix in range(self.xwidth):
x = self.calc_position(ix, self.minx)
x = self.calc_grid_position(ix, self.minx)
for iy in range(self.ywidth):
y = self.calc_position(iy, self.miny)
y = self.calc_grid_position(iy, self.miny)
for iox, ioy in zip(ox, oy):
d = math.sqrt((iox - x)**2 + (ioy - y)**2)
d = math.sqrt((iox - x) ** 2 + (ioy - y) ** 2)
if d <= self.rr:
self.obmap[ix][iy] = True
break
def get_motion_model(self):
@staticmethod
def get_motion_model():
# dx, dy, cost
motion = [[1, 0, 1],
[0, 1, 1],