Files
PythonRobotics/PathPlanning/ReedsSheppPath/reeds_shepp_path_planning.py
Atsushi Sakai 29c02fae58 code clean up
2020-01-29 21:49:30 +09:00

405 lines
10 KiB
Python

"""
Reeds Shepp path planner sample code
author Atsushi Sakai(@Atsushi_twi)
"""
import math
import matplotlib.pyplot as plt
import numpy as np
show_animation = True
class Path:
def __init__(self):
self.lengths = []
self.ctypes = []
self.L = 0.0
self.x = []
self.y = []
self.yaw = []
self.directions = []
def plot_arrow(x, y, yaw, length=1.0, width=0.5, fc="r", ec="k"):
"""
Plot arrow
"""
if not isinstance(x, float):
for (ix, iy, iyaw) in zip(x, y, yaw):
plot_arrow(ix, iy, iyaw)
else:
plt.arrow(x, y, length * math.cos(yaw), length * math.sin(yaw),
fc=fc, ec=ec, head_width=width, head_length=width)
plt.plot(x, y)
def mod2pi(x):
v = np.mod(x, 2.0 * math.pi)
if v < -math.pi:
v += 2.0 * math.pi
else:
if v > math.pi:
v -= 2.0 * math.pi
return v
def straight_left_straight(x, y, phi):
phi = mod2pi(phi)
if y > 0.0 and 0.0 < phi < math.pi * 0.99:
xd = - y / math.tan(phi) + x
t = xd - math.tan(phi / 2.0)
u = phi
v = math.sqrt((x - xd) ** 2 + y ** 2) - math.tan(phi / 2.0)
return True, t, u, v
elif y < 0.0 < phi < math.pi * 0.99:
xd = - y / math.tan(phi) + x
t = xd - math.tan(phi / 2.0)
u = phi
v = -math.sqrt((x - xd) ** 2 + y ** 2) - math.tan(phi / 2.0)
return True, t, u, v
return False, 0.0, 0.0, 0.0
def set_path(paths, lengths, ctypes):
path = Path()
path.ctypes = ctypes
path.lengths = lengths
# check same path exist
for tpath in paths:
typeissame = (tpath.ctypes == path.ctypes)
if typeissame:
if sum(tpath.lengths) - sum(path.lengths) <= 0.01:
return paths # not insert path
path.L = sum([abs(i) for i in lengths])
# Base.Test.@test path.L >= 0.01
if path.L >= 0.01:
paths.append(path)
return paths
def straight_curve_straight(x, y, phi, paths):
flag, t, u, v = straight_left_straight(x, y, phi)
if flag:
paths = set_path(paths, [t, u, v], ["S", "L", "S"])
flag, t, u, v = straight_left_straight(x, -y, -phi)
if flag:
paths = set_path(paths, [t, u, v], ["S", "R", "S"])
return paths
def polar(x, y):
r = math.sqrt(x ** 2 + y ** 2)
theta = math.atan2(y, x)
return r, theta
def left_straight_left(x, y, phi):
u, t = polar(x - math.sin(phi), y - 1.0 + math.cos(phi))
if t >= 0.0:
v = mod2pi(phi - t)
if v >= 0.0:
return True, t, u, v
return False, 0.0, 0.0, 0.0
def left_right_left(x, y, phi):
u1, t1 = polar(x - math.sin(phi), y - 1.0 + math.cos(phi))
if u1 <= 4.0:
u = -2.0 * math.asin(0.25 * u1)
t = mod2pi(t1 + 0.5 * u + math.pi)
v = mod2pi(phi - t + u)
if t >= 0.0 >= u:
return True, t, u, v
return False, 0.0, 0.0, 0.0
def curve_curve_curve(x, y, phi, paths):
flag, t, u, v = left_right_left(x, y, phi)
if flag:
paths = set_path(paths, [t, u, v], ["L", "R", "L"])
flag, t, u, v = left_right_left(-x, y, -phi)
if flag:
paths = set_path(paths, [-t, -u, -v], ["L", "R", "L"])
flag, t, u, v = left_right_left(x, -y, -phi)
if flag:
paths = set_path(paths, [t, u, v], ["R", "L", "R"])
flag, t, u, v = left_right_left(-x, -y, phi)
if flag:
paths = set_path(paths, [-t, -u, -v], ["R", "L", "R"])
# backwards
xb = x * math.cos(phi) + y * math.sin(phi)
yb = x * math.sin(phi) - y * math.cos(phi)
flag, t, u, v = left_right_left(xb, yb, phi)
if flag:
paths = set_path(paths, [v, u, t], ["L", "R", "L"])
flag, t, u, v = left_right_left(-xb, yb, -phi)
if flag:
paths = set_path(paths, [-v, -u, -t], ["L", "R", "L"])
flag, t, u, v = left_right_left(xb, -yb, -phi)
if flag:
paths = set_path(paths, [v, u, t], ["R", "L", "R"])
flag, t, u, v = left_right_left(-xb, -yb, phi)
if flag:
paths = set_path(paths, [-v, -u, -t], ["R", "L", "R"])
return paths
def curve_straight_curve(x, y, phi, paths):
flag, t, u, v = left_straight_left(x, y, phi)
if flag:
paths = set_path(paths, [t, u, v], ["L", "S", "L"])
flag, t, u, v = left_straight_left(-x, y, -phi)
if flag:
paths = set_path(paths, [-t, -u, -v], ["L", "S", "L"])
flag, t, u, v = left_straight_left(x, -y, -phi)
if flag:
paths = set_path(paths, [t, u, v], ["R", "S", "R"])
flag, t, u, v = left_straight_left(-x, -y, phi)
if flag:
paths = set_path(paths, [-t, -u, -v], ["R", "S", "R"])
flag, t, u, v = left_straight_right(x, y, phi)
if flag:
paths = set_path(paths, [t, u, v], ["L", "S", "R"])
flag, t, u, v = left_straight_right(-x, y, -phi)
if flag:
paths = set_path(paths, [-t, -u, -v], ["L", "S", "R"])
flag, t, u, v = left_straight_right(x, -y, -phi)
if flag:
paths = set_path(paths, [t, u, v], ["R", "S", "L"])
flag, t, u, v = left_straight_right(-x, -y, phi)
if flag:
paths = set_path(paths, [-t, -u, -v], ["R", "S", "L"])
return paths
def left_straight_right(x, y, phi):
u1, t1 = polar(x + math.sin(phi), y - 1.0 - math.cos(phi))
u1 = u1 ** 2
if u1 >= 4.0:
u = math.sqrt(u1 - 4.0)
theta = math.atan2(2.0, u)
t = mod2pi(t1 + theta)
v = mod2pi(t - phi)
if t >= 0.0 and v >= 0.0:
return True, t, u, v
return False, 0.0, 0.0, 0.0
def generate_path(q0, q1, max_curvature):
dx = q1[0] - q0[0]
dy = q1[1] - q0[1]
dth = q1[2] - q0[2]
c = math.cos(q0[2])
s = math.sin(q0[2])
x = (c * dx + s * dy) * max_curvature
y = (-s * dx + c * dy) * max_curvature
paths = []
paths = straight_curve_straight(x, y, dth, paths)
paths = curve_straight_curve(x, y, dth, paths)
paths = curve_curve_curve(x, y, dth, paths)
return paths
def interpolate(ind, length, mode, max_curvature, origin_x, origin_y, origin_yaw, path_x, path_y, path_yaw, directions):
if mode == "S":
path_x[ind] = origin_x + length / max_curvature * math.cos(origin_yaw)
path_y[ind] = origin_y + length / max_curvature * math.sin(origin_yaw)
path_yaw[ind] = origin_yaw
else: # curve
ldx = math.sin(length) / max_curvature
ldy = 0.0
if mode == "L": # left turn
ldy = (1.0 - math.cos(length)) / max_curvature
elif mode == "R": # right turn
ldy = (1.0 - math.cos(length)) / -max_curvature
gdx = math.cos(-origin_yaw) * ldx + math.sin(-origin_yaw) * ldy
gdy = -math.sin(-origin_yaw) * ldx + math.cos(-origin_yaw) * ldy
path_x[ind] = origin_x + gdx
path_y[ind] = origin_y + gdy
if mode == "L": # left turn
path_yaw[ind] = origin_yaw + length
elif mode == "R": # right turn
path_yaw[ind] = origin_yaw - length
if length > 0.0:
directions[ind] = 1
else:
directions[ind] = -1
return path_x, path_y, path_yaw, directions
def generate_local_course(total_length, lengths, mode, max_curvature, step_size):
n_point = math.trunc(total_length / step_size) + len(lengths) + 4
px = [0.0 for _ in range(n_point)]
py = [0.0 for _ in range(n_point)]
pyaw = [0.0 for _ in range(n_point)]
directions = [0.0 for _ in range(n_point)]
ind = 1
if lengths[0] > 0.0:
directions[0] = 1
else:
directions[0] = -1
ll = 0.0
for (m, l, i) in zip(mode, lengths, range(len(mode))):
if l > 0.0:
d = step_size
else:
d = -step_size
# set origin state
ox, oy, oyaw = px[ind], py[ind], pyaw[ind]
ind -= 1
if i >= 1 and (lengths[i - 1] * lengths[i]) > 0:
pd = - d - ll
else:
pd = d - ll
while abs(pd) <= abs(l):
ind += 1
px, py, pyaw, directions = interpolate(
ind, pd, m, max_curvature, ox, oy, oyaw, px, py, pyaw, directions)
pd += d
ll = l - pd - d # calc remain length
ind += 1
px, py, pyaw, directions = interpolate(
ind, l, m, max_curvature, ox, oy, oyaw, px, py, pyaw, directions)
# remove unused data
while px[-1] == 0.0:
px.pop()
py.pop()
pyaw.pop()
directions.pop()
return px, py, pyaw, directions
def pi_2_pi(angle):
return (angle + math.pi) % (2 * math.pi) - math.pi
def calc_paths(sx, sy, syaw, gx, gy, gyaw, maxc, step_size):
q0 = [sx, sy, syaw]
q1 = [gx, gy, gyaw]
paths = generate_path(q0, q1, maxc)
for path in paths:
x, y, yaw, directions = generate_local_course(
path.L, path.lengths, path.ctypes, maxc, step_size * maxc)
# convert global coordinate
path.x = [math.cos(-q0[2]) * ix + math.sin(-q0[2])
* iy + q0[0] for (ix, iy) in zip(x, y)]
path.y = [-math.sin(-q0[2]) * ix + math.cos(-q0[2])
* iy + q0[1] for (ix, iy) in zip(x, y)]
path.yaw = [pi_2_pi(iyaw + q0[2]) for iyaw in yaw]
path.directions = directions
path.lengths = [length / maxc for length in path.lengths]
path.L = path.L / maxc
return paths
def reeds_shepp_path_planning(sx, sy, syaw,
gx, gy, gyaw, maxc, step_size=0.2):
paths = calc_paths(sx, sy, syaw, gx, gy, gyaw, maxc, step_size)
if not paths:
return None, None, None, None, None
minL = float("Inf")
best_path_index = -1
for i, _ in enumerate(paths):
if paths[i].L <= minL:
minL = paths[i].L
best_path_index = i
bpath = paths[best_path_index]
return bpath.x, bpath.y, bpath.yaw, bpath.ctypes, bpath.lengths
def main():
print("Reeds Shepp path planner sample start!!")
start_x = -1.0 # [m]
start_y = -4.0 # [m]
start_yaw = np.deg2rad(-20.0) # [rad]
end_x = 5.0 # [m]
end_y = 5.0 # [m]
end_yaw = np.deg2rad(25.0) # [rad]
curvature = 1.0
step_size = 0.1
px, py, pyaw, mode, clen = reeds_shepp_path_planning(
start_x, start_y, start_yaw, end_x, end_y, end_yaw, curvature, step_size)
if show_animation: # pragma: no cover
plt.cla()
plt.plot(px, py, label="final course " + str(mode))
# plotting
plot_arrow(start_x, start_y, start_yaw)
plot_arrow(end_x, end_y, end_yaw)
plt.legend()
plt.grid(True)
plt.axis("equal")
plt.show()
if not px:
assert False, "No path"
if __name__ == '__main__':
main()