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PythonRobotics/PathPlanning/HybridAStar/car.py
2019-03-24 14:09:24 +08:00

92 lines
2.5 KiB
Python

import matplotlib.pyplot as plt
from math import sqrt, cos, sin, tan, pi
WB = 3. # rear to front wheel
W = 2. # width of car
LF = 3.3 # distance from rear to vehicle front end
LB = 1.0 # distance from rear to vehicle back end
MAX_STEER = 0.6 #[rad] maximum steering angle
WBUBBLE_DIST = (LF-LB)/2.0
WBUBBLE_R = sqrt(((LF+LB)/2.0)**2+1)
# vehicle rectangle verticles
VRX = [LF, LF, -LB, -LB, LF]
VRY = [W/2,-W/2,-W/2,W/2,W/2]
def check_car_collision(xlist, ylist, yawlist, ox, oy, kdtree):
for x, y, yaw in zip(xlist, ylist, yawlist):
cx = x + WBUBBLE_DIST*cos(yaw)
cy = y + WBUBBLE_DIST*sin(yaw)
ids = kdtree.search_in_distance([cx, cy], WBUBBLE_R)
if not ids:
continue
if not rectangle_check(x, y, yaw,
[ox[i] for i in ids], [oy[i] for i in ids]):
return False # collision
return True # no collision
def rectangle_check(x, y, yaw, ox, oy):
# transform obstacles to base link frame
c, s = cos(-yaw), sin(-yaw)
for iox, ioy in zip(ox, oy):
tx = iox - x
ty = ioy - y
rx = c*tx - s*ty
ry = s*tx + c*ty
if not (rx > LF or rx < -LB or ry > W/2.0 or ry < -W/2.0):
# print (x, y, yaw, iox, ioy, c, s, rx, ry)
return False # no collision
return True # collision
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 * cos(yaw), length * sin(yaw),
fc=fc, ec=ec, head_width=width, head_length=width, alpha=0.4)
# plt.plot(x, y)
def plot_car(x, y, yaw):
car_color = '-k'
c, s = cos(yaw), sin(yaw)
car_outline_x, car_outline_y = [], []
for rx, ry in zip(VRX, VRY):
tx = c*rx-s*ry + x
ty = s*rx+c*ry + y
car_outline_x.append(tx)
car_outline_y.append(ty)
arrow_x, arrow_y, arrow_yaw = c*1.5+x, s*1.5+y, yaw
plot_arrow(arrow_x, arrow_y, arrow_yaw)
plt.plot(car_outline_x, car_outline_y, car_color)
def pi_2_pi(angle):
return (angle + pi) % (2 * pi) - pi
def move(x, y, yaw, distance, steer, L=WB):
x += distance * cos(yaw)
y += distance * sin(yaw)
yaw += pi_2_pi(distance * tan(steer) / L) # distance/2
return x, y, yaw
if __name__ == '__main__':
x, y, yaw = 0., 0., 1.
plt.axis('equal')
plot_car(x, y, yaw)
plt.show()