Refactor linear_system out of 2017 intake
So we can reuse it!
Change-Id: I0583dbd1fd1a8765468f861a9acba0194aaa8ef6
diff --git a/frc971/control_loops/python/BUILD b/frc971/control_loops/python/BUILD
index c0b71f7..3fa425c 100644
--- a/frc971/control_loops/python/BUILD
+++ b/frc971/control_loops/python/BUILD
@@ -112,3 +112,16 @@
"@matplotlib",
],
)
+
+py_library(
+ name = "linear_system",
+ srcs = ["linear_system.py"],
+ restricted_to = ["//tools:k8"],
+ visibility = ["//visibility:public"],
+ deps = [
+ ":controls",
+ "//aos/util:py_trapezoid_profile",
+ "//frc971/control_loops:python_init",
+ "@matplotlib",
+ ],
+)
diff --git a/frc971/control_loops/python/control_loop.py b/frc971/control_loops/python/control_loop.py
index 2ef2ece..74cd389 100644
--- a/frc971/control_loops/python/control_loop.py
+++ b/frc971/control_loops/python/control_loop.py
@@ -246,6 +246,11 @@
"""
self._name = name
+ @property
+ def name(self):
+ """Returns the name"""
+ return self._name
+
def ContinuousToDiscrete(self, A_continuous, B_continuous, dt):
"""Calculates the discrete time values for A and B.
@@ -531,6 +536,40 @@
self.Kt = self.stall_torque / self.stall_current
+class NMotor(object):
+ def __init__(self, motor, n):
+ """Gangs together n motors."""
+ self.motor = motor
+ self.stall_torque = motor.stall_torque * n
+ self.stall_current = motor.stall_current * n
+ self.free_speed = motor.free_speed
+
+ self.free_current = motor.free_current * n
+ self.resistance = motor.resistance / n
+ self.Kv = motor.Kv
+ self.Kt = motor.Kt
+
+
+class Vex775Pro(object):
+ def __init__(self):
+ # Stall Torque in N m
+ self.stall_torque = 0.71
+ # Stall Current in Amps
+ self.stall_current = 134.0
+ # Free Speed in rad/s
+ self.free_speed = 18730.0 / 60.0 * 2.0 * numpy.pi
+ # Free Current in Amps
+ self.free_current = 0.7
+ # Resistance of the motor
+ self.resistance = 12.0 / self.stall_current
+ # Motor velocity constant
+ self.Kv = (self.free_speed / (12.0 - self.resistance * self.free_current))
+ # Torque constant
+ self.Kt = self.stall_torque / self.stall_current
+ # Motor inertia in kg m^2
+ self.motor_inertia = 0.00001187
+
+
class BAG(object):
# BAG motor specs available at http://motors.vex.com/vexpro-motors/bag-motor
def __init__(self):
diff --git a/frc971/control_loops/python/linear_system.py b/frc971/control_loops/python/linear_system.py
new file mode 100755
index 0000000..21fa4ec
--- /dev/null
+++ b/frc971/control_loops/python/linear_system.py
@@ -0,0 +1,392 @@
+#!/usr/bin/python
+
+from aos.util.trapezoid_profile import TrapezoidProfile
+from frc971.control_loops.python import control_loop
+from frc971.control_loops.python import controls
+import numpy
+import sys
+from matplotlib import pylab
+import glog
+
+
+class LinearSystemParams(object):
+ def __init__(self,
+ name,
+ motor,
+ G,
+ radius,
+ mass,
+ q_pos,
+ q_vel,
+ kalman_q_pos,
+ kalman_q_vel,
+ kalman_q_voltage,
+ kalman_r_position,
+ dt=0.005):
+ self.name = name
+ self.motor = motor
+ self.G = G
+ self.radius = radius
+ self.mass = mass
+ self.q_pos = q_pos
+ self.q_vel = q_vel
+ self.kalman_q_pos = kalman_q_pos
+ self.kalman_q_vel = kalman_q_vel
+ self.kalman_q_voltage = kalman_q_voltage
+ self.kalman_r_position = kalman_r_position
+ self.dt = dt
+
+
+class LinearSystem(control_loop.ControlLoop):
+ def __init__(self, params, name='LinearSystem'):
+ super(LinearSystem, self).__init__(name)
+ self.params = params
+
+ self.motor = params.motor
+
+ # Gear ratio
+ self.G = params.G
+ self.radius = params.radius
+
+ # 5.4 kg of moving mass for the linear_system
+ self.mass = params.mass + self.motor.motor_inertia / (
+ (self.G * self.radius)**2.0)
+
+ # Control loop time step
+ self.dt = params.dt
+
+ # State is [position, velocity]
+ # Input is [Voltage]
+ C1 = self.motor.Kt / (self.G * self.G * self.radius * self.radius *
+ self.motor.resistance * self.mass *
+ self.motor.Kv)
+ C2 = self.motor.Kt / (self.G * self.radius * self.motor.resistance *
+ self.mass)
+
+ self.A_continuous = numpy.matrix([[0, 1], [0, -C1]])
+
+ # Start with the unmodified input
+ self.B_continuous = numpy.matrix([[0], [C2]])
+ glog.debug(repr(self.A_continuous))
+ glog.debug(repr(self.B_continuous))
+
+ 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)
+
+ controllability = controls.ctrb(self.A, self.B)
+ glog.debug('Controllability of %d',
+ numpy.linalg.matrix_rank(controllability))
+ glog.debug('Mass: %f', self.mass)
+ glog.debug('Stall force: %f', self.motor.stall_torque / self.G / self.radius)
+ glog.debug('Stall acceleration: %f', self.motor.stall_torque / self.G /
+ self.radius / self.mass)
+
+ glog.debug('Free speed is %f',
+ -self.B_continuous[1, 0] / self.A_continuous[1, 1] * 12.0)
+
+ self.Q = numpy.matrix([[(1.0 / (self.params.q_pos**2.0)), 0.0],
+ [0.0, (1.0 / (self.params.q_vel**2.0))]])
+
+ self.R = numpy.matrix([[(1.0 / (12.0**2.0))]])
+ self.K = controls.dlqr(self.A, self.B, self.Q, self.R)
+
+ q_pos_ff = 0.005
+ q_vel_ff = 1.0
+ self.Qff = numpy.matrix([[(1.0 / (q_pos_ff**2.0)), 0.0],
+ [0.0, (1.0 / (q_vel_ff**2.0))]])
+
+ self.Kff = controls.TwoStateFeedForwards(self.B, self.Qff)
+
+ glog.debug('K %s', repr(self.K))
+ glog.debug('Poles are %s',
+ repr(numpy.linalg.eig(self.A - self.B * self.K)[0]))
+
+ self.Q = numpy.matrix([[(self.params.kalman_q_pos**2.0), 0.0],
+ [0.0, (self.params.kalman_q_vel**2.0)]])
+
+ self.R = numpy.matrix([[(self.params.kalman_r_position**2.0)]])
+
+ self.KalmanGain, self.Q_steady = controls.kalman(
+ A=self.A, B=self.B, C=self.C, Q=self.Q, R=self.R)
+
+ glog.debug('Kal %s', repr(self.KalmanGain))
+
+ # The box formed by U_min and U_max must encompass all possible values,
+ # or else Austin's code gets angry.
+ self.U_max = numpy.matrix([[12.0]])
+ self.U_min = numpy.matrix([[-12.0]])
+
+ self.InitializeState()
+
+
+class IntegralLinearSystem(LinearSystem):
+ def __init__(self, params, name='IntegralLinearSystem'):
+ super(IntegralLinearSystem, self).__init__(params, name=name)
+
+ self.kalman_q_voltage = params.kalman_q_voltage
+
+ 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
+
+ self.C_unaugmented = self.C
+ self.C = numpy.matrix(numpy.zeros((1, 3)))
+ self.C[0:1, 0:2] = self.C_unaugmented
+
+ self.A, self.B = self.ContinuousToDiscrete(self.A_continuous,
+ self.B_continuous, self.dt)
+
+ self.Q = numpy.matrix(
+ [[(self.params.kalman_q_pos**2.0), 0.0, 0.0],
+ [0.0, (self.params.kalman_q_vel**2.0), 0.0],
+ [0.0, 0.0, (self.params.kalman_q_voltage**2.0)]])
+
+ self.R = numpy.matrix([[(self.params.kalman_r_position**2.0)]])
+
+ self.KalmanGain, self.Q_steady = controls.kalman(
+ A=self.A, B=self.B, C=self.C, Q=self.Q, R=self.R)
+
+ 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 = numpy.concatenate(
+ (self.Kff, numpy.matrix(numpy.zeros((1, 1)))), axis=1)
+
+ self.InitializeState()
+
+
+def RunTest(plant,
+ end_goal,
+ controller,
+ observer=None,
+ duration=1.0,
+ use_profile=True,
+ kick_time=0.5,
+ kick_magnitude=0.0,
+ max_velocity=0.3):
+ """Runs the plant with an initial condition and goal.
+
+ Args:
+ plant: plant object to use.
+ end_goal: end_goal state.
+ controller: Intake object to get K from, or None if we should
+ use plant.
+ observer: Intake object to use for the observer, or None if we should
+ use the actual state.
+ duration: float, time in seconds to run the simulation for.
+ kick_time: float, time in seconds to kick the robot.
+ kick_magnitude: float, disturbance in volts to apply.
+ max_velocity: float, the max speed in m/s to profile.
+ """
+ t_plot = []
+ x_plot = []
+ v_plot = []
+ a_plot = []
+ x_goal_plot = []
+ v_goal_plot = []
+ x_hat_plot = []
+ u_plot = []
+ offset_plot = []
+
+ if controller is None:
+ controller = plant
+
+ vbat = 12.0
+
+ goal = numpy.concatenate(
+ (plant.X, numpy.matrix(numpy.zeros((1, 1)))), axis=0)
+
+ profile = TrapezoidProfile(plant.dt)
+ profile.set_maximum_acceleration(10.0)
+ profile.set_maximum_velocity(max_velocity)
+ profile.SetGoal(goal[0, 0])
+
+ U_last = numpy.matrix(numpy.zeros((1, 1)))
+ iterations = int(duration / plant.dt)
+ for i in xrange(iterations):
+ t = i * plant.dt
+ observer.Y = plant.Y
+ observer.CorrectObserver(U_last)
+
+ offset_plot.append(observer.X_hat[2, 0])
+ x_hat_plot.append(observer.X_hat[0, 0])
+
+ next_goal = numpy.concatenate(
+ (profile.Update(end_goal[0, 0], end_goal[1, 0]),
+ numpy.matrix(numpy.zeros((1, 1)))),
+ axis=0)
+
+ ff_U = controller.Kff * (next_goal - observer.A * goal)
+
+ if use_profile:
+ U_uncapped = controller.K * (goal - observer.X_hat) + ff_U
+ x_goal_plot.append(goal[0, 0])
+ v_goal_plot.append(goal[1, 0])
+ else:
+ U_uncapped = controller.K * (end_goal - observer.X_hat)
+ x_goal_plot.append(end_goal[0, 0])
+ v_goal_plot.append(end_goal[1, 0])
+
+ U = U_uncapped.copy()
+ U[0, 0] = numpy.clip(U[0, 0], -vbat, vbat)
+ x_plot.append(plant.X[0, 0])
+
+ if v_plot:
+ last_v = v_plot[-1]
+ else:
+ last_v = 0
+
+ v_plot.append(plant.X[1, 0])
+ a_plot.append((v_plot[-1] - last_v) / plant.dt)
+
+ u_offset = 0.0
+ if t >= kick_time:
+ u_offset = kick_magnitude
+ plant.Update(U + u_offset)
+
+ observer.PredictObserver(U)
+
+ t_plot.append(t)
+ u_plot.append(U[0, 0])
+
+ ff_U -= U_uncapped - U
+ goal = controller.A * goal + controller.B * ff_U
+
+ if U[0, 0] != U_uncapped[0, 0]:
+ profile.MoveCurrentState(
+ numpy.matrix([[goal[0, 0]], [goal[1, 0]]]))
+
+ glog.debug('Time: %f', t_plot[-1])
+ glog.debug('goal_error %s', repr(end_goal - goal))
+ glog.debug('error %s', repr(observer.X_hat - end_goal))
+
+ pylab.subplot(3, 1, 1)
+ pylab.plot(t_plot, x_plot, label='x')
+ pylab.plot(t_plot, x_hat_plot, label='x_hat')
+ pylab.plot(t_plot, x_goal_plot, label='x_goal')
+ pylab.legend()
+
+ pylab.subplot(3, 1, 2)
+ pylab.plot(t_plot, u_plot, label='u')
+ pylab.plot(t_plot, offset_plot, label='voltage_offset')
+ pylab.legend()
+
+ pylab.subplot(3, 1, 3)
+ pylab.plot(t_plot, a_plot, label='a')
+ pylab.legend()
+
+ pylab.show()
+
+
+def PlotStep(params, R):
+ """Plots a step move to the goal.
+
+ Args:
+ R: numpy.matrix(2, 1), the goal"""
+ plant = LinearSystem(params, params.name)
+ controller = IntegralLinearSystem(params, params.name)
+ observer = IntegralLinearSystem(params, params.name)
+
+ # Test moving the system.
+ initial_X = numpy.matrix([[0.0], [0.0]])
+ augmented_R = numpy.matrix(numpy.zeros((3, 1)))
+ augmented_R[0:2, :] = R
+ RunTest(
+ plant,
+ end_goal=augmented_R,
+ controller=controller,
+ observer=observer,
+ duration=2.0,
+ use_profile=False,
+ kick_time=1.0,
+ kick_magnitude=0.0)
+
+
+def PlotKick(params, R):
+ """Plots a step motion with a kick at 1.0 seconds.
+
+ Args:
+ R: numpy.matrix(2, 1), the goal"""
+ plant = LinearSystem(params, params.name)
+ controller = IntegralLinearSystem(params, params.name)
+ observer = IntegralLinearSystem(params, params.name)
+
+ # Test moving the system.
+ initial_X = numpy.matrix([[0.0], [0.0]])
+ augmented_R = numpy.matrix(numpy.zeros((3, 1)))
+ augmented_R[0:2, :] = R
+ RunTest(
+ plant,
+ end_goal=augmented_R,
+ controller=controller,
+ observer=observer,
+ duration=2.0,
+ use_profile=False,
+ kick_time=1.0,
+ kick_magnitude=2.0)
+
+
+def PlotMotion(params, R, max_velocity=0.3):
+ """Plots a trapezoidal motion.
+
+ Args:
+ R: numpy.matrix(2, 1), the goal,
+ max_velocity: float, The max velocity of the profile.
+ """
+ plant = LinearSystem(params, params.name)
+ controller = IntegralLinearSystem(params, params.name)
+ observer = IntegralLinearSystem(params, params.name)
+
+ # Test moving the system.
+ initial_X = numpy.matrix([[0.0], [0.0]])
+ augmented_R = numpy.matrix(numpy.zeros((3, 1)))
+ augmented_R[0:2, :] = R
+ RunTest(
+ plant,
+ end_goal=augmented_R,
+ controller=controller,
+ observer=observer,
+ duration=2.0,
+ use_profile=True,
+ max_velocity=max_velocity)
+
+
+def WriteLinearSystem(params, plant_files, controller_files, year_namespaces):
+ """Writes out the constants for a linear system to a file.
+
+ Args:
+ params: LinearSystemParams, 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.
+ year_namespaces: list of strings, the namespace list to use.
+ """
+ # Write the generated constants out to a file.
+ linear_system = LinearSystem(params, params.name)
+ loop_writer = control_loop.ControlLoopWriter(
+ linear_system.name, [linear_system], namespaces=year_namespaces)
+ loop_writer.AddConstant(
+ control_loop.Constant('kFreeSpeed', '%f', linear_system.motor.
+ free_speed / (2.0 * numpy.pi)))
+ loop_writer.AddConstant(
+ control_loop.Constant('kOutputRatio', '%f', linear_system.G *
+ linear_system.radius))
+ loop_writer.Write(plant_files[0], plant_files[1])
+
+ integral_linear_system = IntegralLinearSystem(params,
+ 'Integral' + params.name)
+ integral_loop_writer = control_loop.ControlLoopWriter(
+ integral_linear_system.name, [integral_linear_system],
+ namespaces=year_namespaces)
+ integral_loop_writer.Write(controller_files[0], controller_files[1])