Move shared flywheel code into frc971
Signed-off-by: Maxwell Henderson <mxwhenderson@gmail.com>
Change-Id: Ieac317a3e5bc8243e63473f485a2467b74aed348
diff --git a/frc971/control_loops/python/flywheel.py b/frc971/control_loops/python/flywheel.py
new file mode 100644
index 0000000..1280b36
--- /dev/null
+++ b/frc971/control_loops/python/flywheel.py
@@ -0,0 +1,329 @@
+from frc971.control_loops.python import control_loop
+from frc971.control_loops.python import controls
+import numpy
+
+import matplotlib
+import matplotlib.pyplot as plt
+
+import glog
+
+
+class FlywheelParams(object):
+
+ def __init__(self,
+ name,
+ motor,
+ G,
+ J,
+ q_pos,
+ q_vel,
+ q_voltage,
+ r_pos,
+ controller_poles,
+ dt=0.00505):
+ self.name = name
+ self.motor = motor
+ self.G = G
+ self.J = J
+ self.q_pos = q_pos
+ self.q_vel = q_vel
+ self.q_voltage = q_voltage
+ self.r_pos = r_pos
+ self.dt = dt
+ self.controller_poles = controller_poles
+
+
+class VelocityFlywheel(control_loop.HybridControlLoop):
+
+ def __init__(self, params, name="Flywheel"):
+ super(VelocityFlywheel, self).__init__(name=name)
+ self.params = params
+ # Set Motor
+ self.motor = self.params.motor
+ # Moment of inertia of the flywheel wheel in kg m^2
+ self.J = self.params.J
+ # Gear ratio
+ self.G = self.params.G
+ # Control loop time step
+ self.dt = self.params.dt
+
+ # State feedback matrices
+ # [angular velocity]
+ self.A_continuous = numpy.matrix([[
+ -self.motor.Kt / self.motor.Kv /
+ (self.J * self.G * self.G * self.motor.resistance)
+ ]])
+ self.B_continuous = numpy.matrix(
+ [[self.motor.Kt / (self.J * self.G * self.motor.resistance)]])
+ self.C = numpy.matrix([[1]])
+ self.D = numpy.matrix([[0]])
+
+ self.A, self.B = self.ContinuousToDiscrete(self.A_continuous,
+ self.B_continuous, self.dt)
+
+ self.PlaceControllerPoles(self.params.controller_poles)
+
+ # Generated controller not used.
+ self.PlaceObserverPoles([0.3])
+
+ self.U_max = numpy.matrix([[12.0]])
+ self.U_min = numpy.matrix([[-12.0]])
+
+ qff_vel = 8.0
+ self.Qff = numpy.matrix([[1.0 / (qff_vel**2.0)]])
+
+ self.Kff = controls.TwoStateFeedForwards(self.B, self.Qff)
+
+ glog.debug('K: %s', str(self.K))
+ glog.debug('Poles: %s',
+ str(numpy.linalg.eig(self.A - self.B * self.K)[0]))
+
+
+class Flywheel(VelocityFlywheel):
+
+ def __init__(self, params, name="Flywheel"):
+ super(Flywheel, self).__init__(params, name=name)
+
+ self.A_continuous_unaugmented = self.A_continuous
+ self.B_continuous_unaugmented = self.B_continuous
+
+ self.A_continuous = numpy.matrix(numpy.zeros((2, 2)))
+ self.A_continuous[1:2, 1:2] = self.A_continuous_unaugmented
+ self.A_continuous[0, 1] = 1
+
+ self.B_continuous = numpy.matrix(numpy.zeros((2, 1)))
+ self.B_continuous[1:2, 0] = self.B_continuous_unaugmented
+
+ # State feedback matrices
+ # [position, angular velocity]
+ self.C = numpy.matrix([[1, 0]])
+ self.D = numpy.matrix([[0]])
+
+ self.A, self.B = self.ContinuousToDiscrete(self.A_continuous,
+ self.B_continuous, self.dt)
+
+ rpl = 0.45
+ ipl = 0.07
+ self.PlaceObserverPoles([rpl + 1j * ipl, rpl - 1j * ipl])
+
+ self.K_unaugmented = self.K
+ self.K = numpy.matrix(numpy.zeros((1, 2)))
+ self.K[0, 1:2] = self.K_unaugmented
+ self.Kff_unaugmented = self.Kff
+ self.Kff = numpy.matrix(numpy.zeros((1, 2)))
+ self.Kff[0, 1:2] = self.Kff_unaugmented
+
+ self.InitializeState()
+
+
+class IntegralFlywheel(Flywheel):
+
+ def __init__(self, params, name="IntegralFlywheel"):
+ super(IntegralFlywheel, self).__init__(params, name=name)
+
+ self.A_continuous_unaugmented = self.A_continuous
+ self.B_continuous_unaugmented = self.B_continuous
+
+ self.A_continuous = numpy.matrix(numpy.zeros((3, 3)))
+ self.A_continuous[0:2, 0:2] = self.A_continuous_unaugmented
+ self.A_continuous[0:2, 2] = self.B_continuous_unaugmented
+
+ self.B_continuous = numpy.matrix(numpy.zeros((3, 1)))
+ self.B_continuous[0:2, 0] = self.B_continuous_unaugmented
+
+ # states
+ # [position, velocity, voltage_error]
+ self.C_unaugmented = self.C
+ self.C = numpy.matrix(numpy.zeros((1, 3)))
+ self.C[0:1, 0:2] = self.C_unaugmented
+
+ glog.debug('A_continuous %s' % str(self.A_continuous))
+ glog.debug('B_continuous %s' % str(self.B_continuous))
+ glog.debug('C %s' % str(self.C))
+
+ self.A, self.B = self.ContinuousToDiscrete(self.A_continuous,
+ self.B_continuous, self.dt)
+
+ glog.debug('A %s' % str(self.A))
+ glog.debug('B %s' % str(self.B))
+
+ q_pos = self.params.q_pos
+ q_vel = self.params.q_vel
+ q_voltage = self.params.q_voltage
+ self.Q_continuous = numpy.matrix([[(q_pos**2.0), 0.0, 0.0],
+ [0.0, (q_vel**2.0), 0.0],
+ [0.0, 0.0, (q_voltage**2.0)]])
+
+ r_pos = self.params.r_pos
+ self.R_continuous = numpy.matrix([[(r_pos**2.0)]])
+
+ _, _, self.Q, self.R = controls.kalmd(A_continuous=self.A_continuous,
+ B_continuous=self.B_continuous,
+ Q_continuous=self.Q_continuous,
+ R_continuous=self.R_continuous,
+ dt=self.dt)
+
+ glog.debug('Q_discrete %s' % (str(self.Q)))
+ glog.debug('R_discrete %s' % (str(self.R)))
+
+ self.KalmanGain, self.P_steady_state = controls.kalman(A=self.A,
+ B=self.B,
+ C=self.C,
+ Q=self.Q,
+ R=self.R)
+ self.L = self.A * self.KalmanGain
+
+ self.K_unaugmented = self.K
+ self.K = numpy.matrix(numpy.zeros((1, 3)))
+ self.K[0, 0:2] = self.K_unaugmented
+ self.K[0, 2] = 1
+ self.Kff_unaugmented = self.Kff
+ self.Kff = numpy.matrix(numpy.zeros((1, 3)))
+ self.Kff[0, 0:2] = self.Kff_unaugmented
+
+ self.InitializeState()
+
+
+def PlotSpinup(params, goal, iterations=400):
+ """Runs the flywheel plant with an initial condition and goal.
+
+ Args:
+ flywheel: Flywheel object to use.
+ goal: goal state.
+ iterations: Number of timesteps to run the model for.
+ controller_flywheel: Flywheel object to get K from, or None if we should
+ use flywheel.
+ observer_flywheel: Flywheel object to use for the observer, or None if we
+ should use the actual state.
+ """
+
+ # Various lists for graphing things.
+ t = []
+ x = []
+ v = []
+ a = []
+ x_hat = []
+ u = []
+ offset = []
+
+ flywheel = Flywheel(params, params.name)
+ controller_flywheel = IntegralFlywheel(params, params.name)
+ observer_flywheel = IntegralFlywheel(params, params.name)
+ vbat = 12.0
+
+ if t:
+ initial_t = t[-1] + flywheel.dt
+ else:
+ initial_t = 0
+
+ for i in range(iterations):
+ X_hat = flywheel.X
+
+ if observer_flywheel is not None:
+ X_hat = observer_flywheel.X_hat
+ x_hat.append(observer_flywheel.X_hat[1, 0])
+
+ ff_U = controller_flywheel.Kff * (goal - observer_flywheel.A * goal)
+
+ U = controller_flywheel.K * (goal - X_hat) + ff_U
+ U[0, 0] = numpy.clip(U[0, 0], -vbat, vbat)
+ x.append(flywheel.X[0, 0])
+
+ if v:
+ last_v = v[-1]
+ else:
+ last_v = 0
+
+ v.append(flywheel.X[1, 0])
+ a.append((v[-1] - last_v) / flywheel.dt)
+
+ if observer_flywheel is not None:
+ observer_flywheel.Y = flywheel.Y
+ observer_flywheel.CorrectHybridObserver(U)
+ offset.append(observer_flywheel.X_hat[2, 0])
+
+ applied_U = U.copy()
+ if i > 200:
+ applied_U += 2
+ flywheel.Update(applied_U)
+
+ if observer_flywheel is not None:
+ observer_flywheel.PredictHybridObserver(U, flywheel.dt)
+
+ t.append(initial_t + i * flywheel.dt)
+ u.append(U[0, 0])
+
+ matplotlib.use("GTK3Agg")
+
+ plt.subplot(3, 1, 1)
+ plt.plot(t, v, label='x')
+ plt.plot(t, x_hat, label='x_hat')
+ plt.legend()
+
+ plt.subplot(3, 1, 2)
+ plt.plot(t, u, label='u')
+ plt.plot(t, offset, label='voltage_offset')
+ plt.legend()
+
+ plt.subplot(3, 1, 3)
+ plt.plot(t, a, label='a')
+ plt.legend()
+
+ plt.show()
+
+
+def WriteFlywheel(params, plant_files, controller_files, namespace):
+ """Writes out the constants for a flywheel to a file.
+
+ Args:
+ params: list of Flywheel Params, the
+ parameters defining the system.
+ plant_files: list of strings, the cc and h files for the plant.
+ controller_files: list of strings, the cc and h files for the integral
+ controller.
+ namespaces: list of strings, the namespace list to use.
+ """
+ # Write the generated constants out to a file.
+ flywheels = []
+ integral_flywheels = []
+
+ if type(params) is list:
+ name = params[0].name
+ for index, param in enumerate(params):
+ flywheels.append(Flywheel(param, name=param.name + str(index)))
+ integral_flywheels.append(
+ IntegralFlywheel(param,
+ name='Integral' + param.name + str(index)))
+ else:
+ name = params.name
+ flywheels.append(Flywheel(params, params.name))
+ integral_flywheels.append(
+ IntegralFlywheel(params, name='Integral' + params.name))
+
+ loop_writer = control_loop.ControlLoopWriter(name,
+ flywheels,
+ namespaces=namespace)
+ loop_writer.AddConstant(
+ control_loop.Constant('kOutputRatio', '%f', flywheels[0].G))
+ loop_writer.AddConstant(
+ control_loop.Constant('kFreeSpeed', '%f',
+ flywheels[0].motor.free_speed))
+ loop_writer.AddConstant(
+ control_loop.Constant('kBemf',
+ '%f',
+ flywheels[0].motor.Kv * flywheels[0].G,
+ comment="// Radians/sec / volt"))
+ loop_writer.AddConstant(
+ control_loop.Constant('kResistance',
+ '%f',
+ flywheels[0].motor.resistance,
+ comment="// Ohms"))
+ loop_writer.Write(plant_files[0], plant_files[1])
+
+ integral_loop_writer = control_loop.ControlLoopWriter(
+ 'Integral' + name,
+ integral_flywheels,
+ namespaces=namespace,
+ plant_type='StateFeedbackHybridPlant',
+ observer_type='HybridKalman')
+ integral_loop_writer.Write(controller_files[0], controller_files[1])