def __init__(self, width=100, length=100,
target_speed=0.1,
target_color=0,
target_radius=0.05,
target_start_distance=1,
target_id_dynamics='d_SE2_fwd_v',
target_stabilize_phi= -np.pi,
world_texture=random_checkerboard(0.5)):
self.width = width
self.target_stabilize_phi = target_stabilize_phi
self.length = length
self.target_dynamics = instance_dynamics(target_id_dynamics)
self.target_speed = target_speed
self.target_radius = target_radius
self.target_start_distance = target_start_distance
r = 1
bounds = [[-width * r, +width * r],
[-length * r, +length * r],
[0, 5]]
World.__init__(self, bounds)
self.box = box(0, world_texture, width, length)
self.target = Circle(id_object=1, tags=[],
texture=constant_texture(target_color),
center=[0, 0],
radius=target_radius,
solid=True)
class ChasingWorld(World):
''' A simple example of a dynamic world. '''
@contract(width='>0', length='>0')
def __init__(self, width=100, length=100,
target_speed=0.1,
target_color=0,
target_radius=0.05,
target_start_distance=1,
target_id_dynamics='d_SE2_fwd_v',
target_stabilize_phi= -np.pi,
world_texture=random_checkerboard(0.5)):
self.width = width
self.target_stabilize_phi = target_stabilize_phi
self.length = length
self.target_dynamics = instance_dynamics(target_id_dynamics)
self.target_speed = target_speed
self.target_radius = target_radius
self.target_start_distance = target_start_distance
r = 1
bounds = [[-width * r, +width * r],
[-length * r, +length * r],
[0, 5]]
World.__init__(self, bounds)
self.box = box(0, world_texture, width, length)
self.target = Circle(id_object=1, tags=[],
texture=constant_texture(target_color),
center=[0, 0],
radius=target_radius,
solid=True)
def get_primitives(self):
return [self.box, self.target]
def update_primitives(self):
target_pose = self.get_target_pose()
self.target.set_center(translation_from_SE2(target_pose))
@contract(returns='SE2')
def get_target_pose(self):
''' Returns the current pose of the target
(according to self.target_state). '''
pose_se3 = self.target_dynamics.joint_state(self.target_state, 0)[0]
return SE2_from_SE3(pose_se3)
def new_episode(self):
vehicle_pose = SE3_from_SE2(SE2_from_xytheta([0, 0, np.pi / 2]))
target_pose = SE2_from_xytheta([self.target_start_distance,
self.target_start_distance,
np.pi / 2])
self.target_state = self.target_dynamics.pose2state(SE3_from_SE2(target_pose))
self.update_primitives()
id_episode = isodate()
return World.Episode(id_episode, vehicle_pose)
def simulate(self, dt, vehicle):
vehicle_pose = SE2_from_SE3(vehicle.get_pose())
target_pose = self.get_target_pose()
relative_pose = SE2.multiply(SE2.inverse(target_pose), vehicle_pose)
t, theta = translation_angle_from_SE2(relative_pose) #@UnusedVariable
# position on field of view
phi = np.arctan2(t[1], t[0])
diff = normalize_pi_scalar(self.target_stabilize_phi - phi)
# torque command
command = -np.sign(diff)
commands = [command]
self.target_state = self.target_dynamics.integrate(self.target_state,
commands, dt)
self.update_primitives()
return [self.target]