# if abs(term1)<abs(term2):
# diff[0,0]= term1
# else:
# diff[0,0]= -term2
# if abs(term3)<abs(term4):
# diff[2,0]= term3
# else:
# diff[2,0]= -term4
# diff[1,0]=desired_linear_system_state[1]-ref[1]
# diff[3,0]=desired_linear_system_state[3]-ref[3]
v=-1*K @ (diff)
obs = np.array(dyn.preprocess_state(x))
# obs = x
u = sess.run(tf.get_default_graph().get_tensor_by_name('pi/add:0'),{tf.get_default_graph().get_tensor_by_name('Placeholder:0'): obs.reshape(1,-1)})
#output of neural network
u = u[0]
m2, f2 = np.split(u,[4])
M = bad_dyn._M_q(x) + np.reshape(m2,(2, 2))
f = bad_dyn._f_q(x) + np.reshape(f2,(2, 1))
control = np.matmul(M, v) + f
learned_controls_path[:,t]=control[:,0]
x=dyn.integrate(x,control)
class DoublePendulumEnv(gym.Env):
def __init__(self, stepsPerRollout, rewardScaling, dynamicsScaling,
preprocessState, uscaling, largerQ):
#calling init method of parent class
super(DoublePendulumEnv, self).__init__()
#setting local parameters
self._preprocess_state = preprocessState
self._num_steps_per_rollout = stepsPerRollout
self._reward_scaling = rewardScaling
self._norm = 2
self._time_step = 0.01
self._uscaling = uscaling
self._largerQ = largerQ
#setting action space dimensions so agent knows output size
self.action_space = spaces.Box(low=-50,
high=50,
shape=(6, ),
dtype=np.float32)
#setting observation space dimensions so agent knows input size
if (self._preprocess_state):
self.observation_space = spaces.Box(low=-100,
high=100,
shape=(6, ),
dtype=np.float32)
else:
self.observation_space = spaces.Box(low=-100,
high=100,
shape=(4, ),
dtype=np.float32)
# TODO: these should match what we get from system identification, once
# we have reliable numbers there.
#setting parameters of quadrotor and creating dynamics object
mass1 = 1.0
mass2 = 1.0
length1 = 1.0
length2 = 1.0
self._dynamics = DoublePendulum(mass1, mass2, length1, length2,
self._time_step)
#creating bad dynamics object
scaling = 0.000001 + dynamicsScaling
self._bad_dynamics = DoublePendulum(scaling * mass1, scaling * mass2,
scaling * length1,
scaling * length2, self._time_step)
#setting other local variables
self.A, self.B, C = self._dynamics.linearized_system()
self._count = 0
self._xdim = self._dynamics.xdim
self._udim = self._dynamics.udim
self._M1, self._f1 = self._bad_dynamics.feedback_linearize()
self._iter_count = 0
def step(self, u):
#compute v based on basic control law
diff = self._dynamics.linear_system_state_delta(
self._reference[self._count], self._current_y)
v = -self._K @ (diff)
#output of neural network
m2, f2 = np.split(self._uscaling * u, [4])
M = self._bad_dynamics._M_q(self._state) + np.reshape(
m2, (self._udim, self._udim))
f = self._bad_dynamics._f_q(self._state) + np.reshape(
f2, (self._udim, 1))
z = np.dot(M, v) + f
self._state = self._dynamics.integrate(self._state, z, self._time_step)
self._current_y = self._dynamics.linearized_system_state(self._state)
reward = self.computeReward(self._y_desired[self._count],
self._current_y)
#Increasing count
self._count += 1
#computing observations, rewards, done, info???
done = False
if (self._count >= self._num_steps_per_rollout):
done = True
#formatting observation
list = []
for x in self._state:
list.append(x[0])
observation = list
#preprocessing observation
if (self._preprocess_state):
observation = self.preprocess_state(observation)
#returning stuff
return np.array(observation), reward, done, {}
def reset(self):
#(0) Sample state using state smapler method
self._state = self.initial_state_sampler()
# (1) Generate a time series for v and corresponding y.
self._reference, self._K = self._generate_reference(self._state)
self._y_desired = self._generate_ys(self._state, self._reference,
self._K)
self._current_y = self._dynamics.linearized_system_state(self._state)
#reset internal count
self._count = 0
#formatting observation
list = []
for x in self._state:
list.append(x[0])
observation = list
#preprocessing state
if (self._preprocess_state):
observation = self.preprocess_state(observation)
return np.array(observation)
def seed(self, s):
np.random.seed(np.random.randomint())
def render(self):
# TODO!
pass
def initial_state_sampler(self):
lower = np.array([[-np.pi], [-0.5], [-np.pi], [-0.5]])
upper = -lower
return np.random.uniform(lower, upper)
def _generate_reference(self, x0):
"""
Use sinusoid with random frequency, amplitude, and bias:
``` vi(k) = a * sin(2 * pi * f * k) + b ```
"""
MAX_CONTINUOUS_TIME_FREQ = 0.1
MAX_DISCRETE_TIME_FREQ = MAX_CONTINUOUS_TIME_FREQ * self._dynamics._time_step
linsys_xdim = self.A.shape[0]
linsys_udim = self.B.shape[1]
#random scaling factor for Q based on how many iterations have been done
if (self._largerQ):
Q = 50 * (np.random.uniform() + 0.1) * np.eye(linsys_xdim)
else:
Q = 10 * np.eye(linsys_xdim)
#fixed Q scaling
# Q = 1.0 * np.diag([1.0, 0.0, 0.0, 0.0,
# 1.0, 0.0, 0.0, 0.0,
# 1.0, 0.0, 0.0, 0.0,
# 1.0, 0.0])
#fixed R scaling
R = 1.0 * np.eye(linsys_udim)
# Initial y.
y0 = self._dynamics.linearized_system_state(x0)
y = np.empty((linsys_xdim, self._num_steps_per_rollout))
for ii in range(linsys_xdim):
y[ii, :] = np.linspace(
0, self._num_steps_per_rollout * self._dynamics._time_step,
self._num_steps_per_rollout)
y[ii, :] = y0[ii, 0] + 1.0 * np.random.uniform() * (1.0 - np.cos(
2.0 * np.pi * MAX_DISCRETE_TIME_FREQ * \
np.random.uniform() * y[ii, :])) #+ 0.1 * np.random.normal()
# Ensure that y ref starts at y0.
assert (np.allclose(y[:, 0].flatten(), y0.flatten(), 1e-5))
P = solve_continuous_are(self.A, self.B, Q, R)
K = np.linalg.inv(R) @ self.B.T @ P
return (np.split(y,
indices_or_sections=self._num_steps_per_rollout,
axis=1), K)
def _generate_ys(self, x0, refs, K):
"""
Compute desired output sequence given initial state and input sequence.
This is computed by applying the true dynamics' feedback linearization.
"""
x = x0.copy()
y = self._dynamics.linearized_system_state(x)
ys = []
for r in refs:
diff = self._dynamics.linear_system_state_delta(r, y)
v = -K @ diff
u = self._dynamics.feedback(x, v)
x = self._dynamics.integrate(x, u)
y = self._dynamics.linearized_system_state(x)
ys.append(y.copy())
return ys
def computeReward(self, y_desired, y):
return -self._reward_scaling * self._dynamics.observation_distance(
y_desired, y, self._norm)
def close(self):
pass
def preprocess_state(self, x):
return self._dynamics.preprocess_state(x)