Files
PathPlanning/CurvesGenerator/dubins_path.py
T
zhm-real 8e232410ed reformat
2020-08-05 12:53:19 -07:00

352 lines
9.1 KiB
Python

"""
Dubins Path
"""
import math
import numpy as np
import matplotlib.pyplot as plt
from scipy.spatial.transform import Rotation as Rot
import CurvesGenerator.draw as draw
# class for PATH element
class PATH:
def __init__(self, L, mode, x, y, yaw):
self.L = L # total path length [float]
self.mode = mode # type of each part of the path [string]
self.x = x # final s positions [m]
self.y = y # final y positions [m]
self.yaw = yaw # final yaw angles [rad]
# utils
def pi_2_pi(theta):
while theta > math.pi:
theta -= 2.0 * math.pi
while theta < -math.pi:
theta += 2.0 * math.pi
return theta
def mod2pi(theta):
return theta - 2.0 * math.pi * math.floor(theta / math.pi / 2.0)
def LSL(alpha, beta, dist):
sin_a = math.sin(alpha)
sin_b = math.sin(beta)
cos_a = math.cos(alpha)
cos_b = math.cos(beta)
cos_a_b = math.cos(alpha - beta)
p_lsl = 2 + dist ** 2 - 2 * cos_a_b + 2 * dist * (sin_a - sin_b)
if p_lsl < 0:
return None, None, None, ["L", "S", "L"]
else:
p_lsl = math.sqrt(p_lsl)
denominate = dist + sin_a - sin_b
t_lsl = mod2pi(-alpha + math.atan2(cos_b - cos_a, denominate))
q_lsl = mod2pi(beta - math.atan2(cos_b - cos_a, denominate))
return t_lsl, p_lsl, q_lsl, ["L", "S", "L"]
def RSR(alpha, beta, dist):
sin_a = math.sin(alpha)
sin_b = math.sin(beta)
cos_a = math.cos(alpha)
cos_b = math.cos(beta)
cos_a_b = math.cos(alpha - beta)
p_rsr = 2 + dist ** 2 - 2 * cos_a_b + 2 * dist * (sin_b - sin_a)
if p_rsr < 0:
return None, None, None, ["R", "S", "R"]
else:
p_rsr = math.sqrt(p_rsr)
denominate = dist - sin_a + sin_b
t_rsr = mod2pi(alpha - math.atan2(cos_a - cos_b, denominate))
q_rsr = mod2pi(-beta + math.atan2(cos_a - cos_b, denominate))
return t_rsr, p_rsr, q_rsr, ["R", "S", "R"]
def LSR(alpha, beta, dist):
sin_a = math.sin(alpha)
sin_b = math.sin(beta)
cos_a = math.cos(alpha)
cos_b = math.cos(beta)
cos_a_b = math.cos(alpha - beta)
p_lsr = -2 + dist ** 2 + 2 * cos_a_b + 2 * dist * (sin_a + sin_b)
if p_lsr < 0:
return None, None, None, ["L", "S", "R"]
else:
p_lsr = math.sqrt(p_lsr)
rec = math.atan2(-cos_a - cos_b, dist + sin_a + sin_b) - math.atan2(-2.0, p_lsr)
t_lsr = mod2pi(-alpha + rec)
q_lsr = mod2pi(-mod2pi(beta) + rec)
return t_lsr, p_lsr, q_lsr, ["L", "S", "R"]
def RSL(alpha, beta, dist):
sin_a = math.sin(alpha)
sin_b = math.sin(beta)
cos_a = math.cos(alpha)
cos_b = math.cos(beta)
cos_a_b = math.cos(alpha - beta)
p_rsl = -2 + dist ** 2 + 2 * cos_a_b - 2 * dist * (sin_a + sin_b)
if p_rsl < 0:
return None, None, None, ["R", "S", "L"]
else:
p_rsl = math.sqrt(p_rsl)
rec = math.atan2(cos_a + cos_b, dist - sin_a - sin_b) - math.atan2(2.0, p_rsl)
t_rsl = mod2pi(alpha - rec)
q_rsl = mod2pi(beta - rec)
return t_rsl, p_rsl, q_rsl, ["R", "S", "L"]
def RLR(alpha, beta, dist):
sin_a = math.sin(alpha)
sin_b = math.sin(beta)
cos_a = math.cos(alpha)
cos_b = math.cos(beta)
cos_a_b = math.cos(alpha - beta)
rec = (6.0 - dist ** 2 + 2.0 * cos_a_b + 2.0 * dist * (sin_a - sin_b)) / 8.0
if abs(rec) > 1.0:
return None, None, None, ["R", "L", "R"]
p_rlr = mod2pi(2 * math.pi - math.acos(rec))
t_rlr = mod2pi(alpha - math.atan2(cos_a - cos_b, dist - sin_a + sin_b) + mod2pi(p_rlr / 2.0))
q_rlr = mod2pi(alpha - beta - t_rlr + mod2pi(p_rlr))
return t_rlr, p_rlr, q_rlr, ["R", "L", "R"]
def LRL(alpha, beta, dist):
sin_a = math.sin(alpha)
sin_b = math.sin(beta)
cos_a = math.cos(alpha)
cos_b = math.cos(beta)
cos_a_b = math.cos(alpha - beta)
rec = (6.0 - dist ** 2 + 2.0 * cos_a_b + 2.0 * dist * (sin_b - sin_a)) / 8.0
if abs(rec) > 1.0:
return None, None, None, ["L", "R", "L"]
p_lrl = mod2pi(2 * math.pi - math.acos(rec))
t_lrl = mod2pi(-alpha - math.atan2(cos_a - cos_b, dist + sin_a - sin_b) + p_lrl / 2.0)
q_lrl = mod2pi(mod2pi(beta) - alpha - t_lrl + mod2pi(p_lrl))
return t_lrl, p_lrl, q_lrl, ["L", "R", "L"]
def interpolate(ind, l, m, maxc, ox, oy, oyaw, px, py, pyaw, directions):
if m == "S":
px[ind] = ox + l / maxc * math.cos(oyaw)
py[ind] = oy + l / maxc * math.sin(oyaw)
pyaw[ind] = oyaw
else:
ldx = math.sin(l) / maxc
if m == "L":
ldy = (1.0 - math.cos(l)) / maxc
elif m == "R":
ldy = (1.0 - math.cos(l)) / (-maxc)
gdx = math.cos(-oyaw) * ldx + math.sin(-oyaw) * ldy
gdy = -math.sin(-oyaw) * ldx + math.cos(-oyaw) * ldy
px[ind] = ox + gdx
py[ind] = oy + gdy
if m == "L":
pyaw[ind] = oyaw + l
elif m == "R":
pyaw[ind] = oyaw - l
if l > 0.0:
directions[ind] = 1
else:
directions[ind] = -1
return px, py, pyaw, directions
def generate_local_course(L, lengths, mode, maxc, step_size):
point_num = int(L / step_size) + len(lengths) + 3
px = [0.0 for _ in range(point_num)]
py = [0.0 for _ in range(point_num)]
pyaw = [0.0 for _ in range(point_num)]
directions = [0 for _ in range(point_num)]
ind = 1
if lengths[0] > 0.0:
directions[0] = 1
else:
directions[0] = -1
if lengths[0] > 0.0:
d = step_size
else:
d = -step_size
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
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, maxc, 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, maxc, ox, oy, oyaw, px, py, pyaw, directions)
if len(px) <= 1:
return [], [], [], []
# remove unused data
while len(px) >= 1 and px[-1] == 0.0:
px.pop()
py.pop()
pyaw.pop()
directions.pop()
return px, py, pyaw, directions
def planning_from_origin(gx, gy, gyaw, curv, step_size):
D = math.hypot(gx, gy)
d = D * curv
theta = mod2pi(math.atan2(gy, gx))
alpha = mod2pi(-theta)
beta = mod2pi(gyaw - theta)
planners = [LSL, RSR, LSR, RSL, RLR, LRL]
best_cost = float("inf")
bt, bp, bq, best_mode = None, None, None, None
for planner in planners:
t, p, q, mode = planner(alpha, beta, d)
if t is None:
continue
cost = (abs(t) + abs(p) + abs(q))
if best_cost > cost:
bt, bp, bq, best_mode = t, p, q, mode
best_cost = cost
lengths = [bt, bp, bq]
x_list, y_list, yaw_list, directions = generate_local_course(
sum(lengths), lengths, best_mode, curv, step_size)
return x_list, y_list, yaw_list, best_mode, best_cost
def calc_dubins_path(sx, sy, syaw, gx, gy, gyaw, curv, step_size=0.1):
gx = gx - sx
gy = gy - sy
l_rot = Rot.from_euler('z', syaw).as_dcm()[0:2, 0:2]
le_xy = np.stack([gx, gy]).T @ l_rot
le_yaw = gyaw - syaw
lp_x, lp_y, lp_yaw, mode, lengths = planning_from_origin(
le_xy[0], le_xy[1], le_yaw, curv, step_size)
rot = Rot.from_euler('z', -syaw).as_dcm()[0:2, 0:2]
converted_xy = np.stack([lp_x, lp_y]).T @ rot
x_list = converted_xy[:, 0] + sx
y_list = converted_xy[:, 1] + sy
yaw_list = [pi_2_pi(i_yaw + syaw) for i_yaw in lp_yaw]
return PATH(lengths, mode, x_list, y_list, yaw_list)
def main():
# choose states pairs: (s, y, yaw)
# simulation-1
states = [(0, 0, 0), (10, 10, -90), (20, 5, 60), (30, 10, 120),
(35, -5, 30), (25, -10, -120), (15, -15, 100), (0, -10, -90)]
# simulation-2
# states = [(-3, 3, 120), (10, -7, 30), (10, 13, 30), (20, 5, -25),
# (35, 10, 180), (32, -10, 180), (5, -12, 90)]
max_c = 0.25 # max curvature
path_x, path_y, yaw = [], [], []
for i in range(len(states) - 1):
s_x = states[i][0]
s_y = states[i][1]
s_yaw = np.deg2rad(states[i][2])
g_x = states[i + 1][0]
g_y = states[i + 1][1]
g_yaw = np.deg2rad(states[i + 1][2])
path_i = calc_dubins_path(s_x, s_y, s_yaw, g_x, g_y, g_yaw, max_c)
for x, y, iyaw in zip(path_i.x, path_i.y, path_i.yaw):
path_x.append(x)
path_y.append(y)
yaw.append(iyaw)
# animation
plt.ion()
plt.figure(1)
for i in range(len(path_x)):
plt.clf()
plt.plot(path_x, path_y, linewidth=1, color='gray')
for x, y, theta in states:
draw.Arrow(x, y, np.deg2rad(theta), 2, 'blueviolet')
draw.Car(path_x[i], path_y[i], yaw[i], 1.5, 3)
plt.axis("equal")
plt.title("Simulation of Dubins Path")
plt.axis([-10, 42, -20, 20])
plt.draw()
plt.pause(0.001)
plt.pause(1)
if __name__ == '__main__':
main()