mirror of
https://github.com/AtsushiSakai/PythonRobotics.git
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103 lines
2.6 KiB
Python
103 lines
2.6 KiB
Python
"""
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Car model for Hybrid A* path planning
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author: Zheng Zh (@Zhengzh)
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"""
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import matplotlib.pyplot as plt
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from math import sqrt, cos, sin, tan, pi
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WB = 3. # rear to front wheel
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W = 2. # width of car
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LF = 3.3 # distance from rear to vehicle front end
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LB = 1.0 # distance from rear to vehicle back end
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MAX_STEER = 0.6 # [rad] maximum steering angle
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WBUBBLE_DIST = (LF - LB) / 2.0
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WBUBBLE_R = sqrt(((LF + LB) / 2.0)**2 + 1)
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# vehicle rectangle verticles
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VRX = [LF, LF, -LB, -LB, LF]
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VRY = [W / 2, -W / 2, -W / 2, W / 2, W / 2]
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def check_car_collision(xlist, ylist, yawlist, ox, oy, kdtree):
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for x, y, yaw in zip(xlist, ylist, yawlist):
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cx = x + WBUBBLE_DIST * cos(yaw)
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cy = y + WBUBBLE_DIST * sin(yaw)
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ids = kdtree.search_in_distance([cx, cy], WBUBBLE_R)
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if not ids:
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continue
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if not rectangle_check(x, y, yaw,
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[ox[i] for i in ids], [oy[i] for i in ids]):
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return False # collision
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return True # no collision
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def rectangle_check(x, y, yaw, ox, oy):
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# transform obstacles to base link frame
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c, s = cos(-yaw), sin(-yaw)
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for iox, ioy in zip(ox, oy):
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tx = iox - x
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ty = ioy - y
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rx = c * tx - s * ty
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ry = s * tx + c * ty
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if not (rx > LF or rx < -LB or ry > W / 2.0 or ry < -W / 2.0):
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return False # no collision
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return True # collision
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def plot_arrow(x, y, yaw, length=1.0, width=0.5, fc="r", ec="k"):
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"""Plot arrow."""
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if not isinstance(x, float):
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for (ix, iy, iyaw) in zip(x, y, yaw):
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plot_arrow(ix, iy, iyaw)
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else:
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plt.arrow(x, y, length * cos(yaw), length * sin(yaw),
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fc=fc, ec=ec, head_width=width, head_length=width, alpha=0.4)
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# plt.plot(x, y)
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def plot_car(x, y, yaw):
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car_color = '-k'
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c, s = cos(yaw), sin(yaw)
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car_outline_x, car_outline_y = [], []
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for rx, ry in zip(VRX, VRY):
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tx = c * rx - s * ry + x
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ty = s * rx + c * ry + y
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car_outline_x.append(tx)
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car_outline_y.append(ty)
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arrow_x, arrow_y, arrow_yaw = c * 1.5 + x, s * 1.5 + y, yaw
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plot_arrow(arrow_x, arrow_y, arrow_yaw)
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plt.plot(car_outline_x, car_outline_y, car_color)
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def pi_2_pi(angle):
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return (angle + pi) % (2 * pi) - pi
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def move(x, y, yaw, distance, steer, L=WB):
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x += distance * cos(yaw)
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y += distance * sin(yaw)
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yaw += pi_2_pi(distance * tan(steer) / L) # distance/2
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return x, y, yaw
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if __name__ == '__main__':
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x, y, yaw = 0., 0., 1.
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plt.axis('equal')
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plot_car(x, y, yaw)
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plt.show() |