Add current control loop python
Signed-off-by: Ravago Jones <ravagojones@gmail.com>
Change-Id: I59639923a5e26e2ca24fbb84878d7eeab1b5067a
diff --git a/frc971/control_loops/python/BUILD b/frc971/control_loops/python/BUILD
index e308954..0066b93 100644
--- a/frc971/control_loops/python/BUILD
+++ b/frc971/control_loops/python/BUILD
@@ -175,6 +175,20 @@
],
)
+py_library(
+ name = "angular_system_current",
+ srcs = ["angular_system_current.py"],
+ target_compatible_with = ["@platforms//cpu:x86_64"],
+ visibility = ["//visibility:public"],
+ deps = [
+ ":controls",
+ "//aos/util:py_trapezoid_profile",
+ "//frc971/control_loops:python_init",
+ "@pip//matplotlib",
+ "@pip//pygobject",
+ ],
+)
+
py_binary(
name = "spline_graph",
srcs = [
diff --git a/frc971/control_loops/python/angular_system_current.py b/frc971/control_loops/python/angular_system_current.py
new file mode 100755
index 0000000..0dc9595
--- /dev/null
+++ b/frc971/control_loops/python/angular_system_current.py
@@ -0,0 +1,512 @@
+#!/usr/bin/python3
+
+from aos.util.trapezoid_profile import TrapezoidProfile
+from frc971.control_loops.python import control_loop
+from frc971.control_loops.python import controls
+import numpy
+from matplotlib import pylab
+import glog
+
+
+class AngularSystemCurrentParams(object):
+
+ def __init__(self,
+ name,
+ motor,
+ G,
+ J,
+ q_pos,
+ q_vel,
+ kalman_q_pos,
+ kalman_q_vel,
+ kalman_q_voltage,
+ kalman_r_position,
+ radius=None,
+ dt=0.00505):
+ """Constructs an AngularSystemCurrentParams object.
+
+ Args:
+ motor: Motor object with the motor constants.
+ G: float, Gear ratio. Less than 1 means output moves slower than the
+ input.
+ J: float, Moment of inertia in kg m^2
+ q_pos: float, controller optimizer weight on position error.
+ q_vel: float, controller optimizer weight on velocity error
+ kalman_q_pos: float, std deviation of the model's position prediction
+ kalman_q_vel: float, std deviation of the model's velocity prediction
+ kalman_q_voltage: float, std deviation of the model's voltage error prediction
+ kalman_r_position: float, std deviation of the position measurement
+ radius: float, radius of the mechanism in meters
+ dt: float, length of the control loop period in seconds
+ """
+ self.name = name
+ self.motor = motor
+ self.G = G
+ self.J = J
+ 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.radius = radius
+ self.dt = dt
+
+
+# An angular system that uses current control instead of voltage
+# The current through the motor directly impacts the torque
+# whereas the effect of an applied voltage depends on the current velocity
+class AngularSystemCurrent(control_loop.ControlLoop):
+
+ def __init__(self, params, name="AngularSystemCurrent"):
+ super(AngularSystemCurrent, self).__init__(name)
+ self.params = params
+
+ self.motor = params.motor
+
+ # Gear ratio
+ self.G = params.G
+
+ # Moment of inertia in kg m^2
+ self.J = params.J + self.motor.motor_inertia / (self.G**2.0)
+
+ # Control loop time step
+ self.dt = params.dt
+
+ # State is [position, velocity]
+ # Input is [Current]
+
+ self.A_continuous = numpy.matrix([[0, 1], [0, 0]])
+
+ # Start with the unmodified input
+ self.B_continuous = numpy.matrix([[0],
+ [self.motor.Kt / (self.G * self.J)]])
+ 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('J: %f', self.J)
+ glog.debug('Stall torque: %f (N m)', self.motor.stall_torque / self.G)
+ if self.params.radius is not None:
+ glog.debug('Stall force: %f (N)',
+ self.motor.stall_torque / self.G / self.params.radius)
+ glog.debug(
+ 'Stall force: %f (lbf)', self.motor.stall_torque / self.G /
+ self.params.radius * 0.224809)
+
+ glog.debug('Stall acceleration: %f (rad/s^2)',
+ self.motor.stall_torque / self.G / self.J)
+
+ glog.debug('Free speed is %f (rad/s)', self.motor.free_speed)
+
+ Q_state_cost = numpy.matrix([[(1.0 / (self.params.q_pos**2.0)), 0.0],
+ [0.0, (1.0 / (self.params.q_vel**2.0))]])
+
+ R_control_cost = numpy.matrix([[(1.0 / (12**2.0))]])
+ self.K = controls.dlqr(self.A, self.B, Q_state_cost, R_control_cost)
+
+ 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]))
+
+ # Process covariance matrix
+ self.Q = numpy.matrix([[(self.params.kalman_q_pos**2.0), 0.0],
+ [0.0, (self.params.kalman_q_vel**2.0)]])
+
+ # Measurement covariance matrix
+ self.R = numpy.matrix([[(self.params.kalman_r_position**2.0)]])
+
+ # From testing, these continuous Q and R's appear to be good approximations of Q and R.
+ self.Q_continuous = self.Q / self.dt
+ self.R_continuous = self.R * self.dt
+
+ self.KalmanGain, self.P_steady_state = 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
+ self.U_max = numpy.matrix([[800.0]])
+ self.U_min = numpy.matrix([[-800.0]])
+
+ # Max current = (12 - w G / Kv) / R
+
+ # These are used to limit the current command based on the available voltage
+ # Used in the form:
+ # U_max = U_limit_coefficient * X + U_limit_constant
+ # U_min = U_limit_coefficient * X - U_limit_constant
+
+ self.U_limit_coefficient = numpy.matrix(
+ [[0, -self.G / self.motor.resistance / self.motor.Kv]])
+ self.U_limit_constant = numpy.matrix([[self.motor.stall_current]])
+
+ self.delayed_u = 1
+
+ self.InitializeState()
+
+
+class IntegralAngularSystemCurrent(AngularSystemCurrent):
+
+ def __init__(self, params, name="IntegralAngularSystemCurrent"):
+ super(IntegralAngularSystemCurrent, 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
+
+ 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)]])
+
+ # From testing, these continuous Q and R's appear to be good approximations of Q and R.
+ self.Q_continuous = self.Q / self.dt
+ self.R_continuous = self.R * self.dt
+
+ self.KalmanGain, self.P_steady_state = 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.U_limit_coefficient_unaugmented = self.U_limit_coefficient
+ self.U_limit_coefficient = numpy.matrix(numpy.zeros((1, 3)))
+ self.U_limit_coefficient[0, 0:2] = self.U_limit_coefficient_unaugmented
+
+ 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=10.0,
+ max_acceleration=70.0):
+ """Runs the plant with an initial condition and goal.
+
+ Args:
+ plant: plant object to use.
+ end_goal: end_goal state.
+ controller: AngularSystemCurrent object to get K from, or None if we should
+ use plant.
+ observer: AngularSystemCurrent 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 maximum velocity for the profile.
+ max_acceleration: float, The maximum acceleration for the profile.
+ """
+ t_plot = []
+ x_plot = []
+ v_plot = []
+ a_plot = []
+ motor_voltage_plot = []
+ motor_current_plot = []
+ battery_current_plot = []
+ x_goal_plot = []
+ v_goal_plot = []
+ x_hat_plot = []
+ u_plot = []
+ u_max_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(max_acceleration)
+ 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 range(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()
+
+ # clip U to max current possible given battery voltage constraints
+ max_current = plant.U_limit_coefficient * plant.X + plant.U_limit_constant
+ min_current = plant.U_limit_coefficient * plant.X - plant.U_limit_constant
+
+ u_max_plot.append(max_current[0, 0])
+ U[0, 0] = numpy.clip(U[0, 0], min_current, max_current)
+
+ motor_voltage = U[0, 0] * plant.motor.resistance + plant.X[
+ 1, 0] * plant.G / plant.motor.Kv
+ motor_voltage_plot.append(motor_voltage)
+
+ motor_current = U[0, 0]
+ motor_current_plot.append(motor_current)
+
+ battery_current = motor_current * motor_voltage / 12.0
+ battery_current_plot.append(battery_current)
+ 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.plot(t_plot, motor_voltage_plot, label='motor_voltage')
+ pylab.legend()
+
+ ax1 = pylab.subplot(3, 1, 3)
+ ax1.set_xlabel("time(s)")
+ ax1.set_ylabel("rad/s^2")
+ ax1.plot(t_plot, a_plot, label='a')
+
+ ax2 = ax1.twinx()
+ ax2.set_xlabel("time(s)")
+ ax2.set_ylabel("Amps")
+ ax2.plot(t_plot, battery_current_plot, 'g', label='battery current')
+ ax2.plot(t_plot, motor_current_plot, 'r', label='motor')
+ ax2.plot(t_plot, u_max_plot, 'b', label='u_max')
+ pylab.legend()
+
+ pylab.show()
+
+
+def PlotStep(params, R, plant_params=None):
+ """Plots a step move to the goal.
+
+ Args:
+ params: AngularSystemParams for the controller and observer
+ plant_params: AngularSystemParams for the plant. Defaults to params if
+ plant_params is None.
+ R: numpy.matrix(2, 1), the goal"""
+ plant = AngularSystemCurrent(plant_params or params, params.name)
+ controller = IntegralAngularSystemCurrent(params, params.name)
+ observer = IntegralAngularSystemCurrent(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=5.0,
+ use_profile=False,
+ kick_time=1.0,
+ kick_magnitude=0.0)
+
+
+def PlotKick(params, R, plant_params=None):
+ """Plots a step motion with a kick at 1.0 seconds.
+
+ Args:
+ params: AngularSystemParams for the controller and observer
+ plant_params: AngularSystemParams for the plant. Defaults to params if
+ plant_params is None.
+ R: numpy.matrix(2, 1), the goal"""
+ plant = AngularSystemCurrent(plant_params or params, params.name)
+ controller = IntegralAngularSystemCurrent(params, params.name)
+ observer = IntegralAngularSystemCurrent(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=10.0,
+ max_acceleration=70.0,
+ plant_params=None):
+ """Plots a trapezoidal motion.
+
+ Args:
+ params: AngularSystemParams for the controller and observer
+ plant_params: AngularSystemParams for the plant. Defaults to params if
+ plant_params is None.
+ R: numpy.matrix(2, 1), the goal,
+ max_velocity: float, The max velocity of the profile.
+ max_acceleration: float, The max acceleration of the profile.
+ """
+ plant = AngularSystemCurrent(plant_params or params, params.name)
+ controller = IntegralAngularSystemCurrent(params, params.name)
+ observer = IntegralAngularSystemCurrent(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,
+ max_acceleration=max_acceleration)
+
+
+def WriteAngularSystemCurrent(params,
+ plant_files,
+ controller_files,
+ year_namespaces,
+ plant_type='StateFeedbackPlant',
+ observer_type='StateFeedbackObserver'):
+ """Writes out the constants for a angular system to a file.
+
+ Args:
+ params: list of AngularSystemCurrentParams or AngularSystemCurrentParams, 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.
+ angular_systems = []
+ integral_angular_systems = []
+
+ if type(params) is list:
+ name = params[0].name
+ for index, param in enumerate(params):
+ angular_systems.append(
+ AngularSystemCurrent(param, param.name + str(index)))
+ integral_angular_systems.append(
+ IntegralAngularSystemCurrent(
+ param, 'Integral' + param.name + str(index)))
+ else:
+ name = params.name
+ angular_systems.append(AngularSystemCurrent(params, params.name))
+ integral_angular_systems.append(
+ IntegralAngularSystemCurrent(params, 'Integral' + params.name))
+
+ loop_writer = control_loop.ControlLoopWriter(name,
+ angular_systems,
+ namespaces=year_namespaces,
+ plant_type=plant_type,
+ observer_type=observer_type)
+ loop_writer.AddConstant(
+ control_loop.Constant('kOutputRatio', '%f', angular_systems[0].G))
+ loop_writer.AddConstant(
+ control_loop.Constant('kFreeSpeed', '%f',
+ angular_systems[0].motor.free_speed))
+ loop_writer.Write(plant_files[0], plant_files[1])
+
+ integral_loop_writer = control_loop.ControlLoopWriter(
+ 'Integral' + name,
+ integral_angular_systems,
+ namespaces=year_namespaces,
+ plant_type=plant_type,
+ observer_type=observer_type)
+ integral_loop_writer.Write(controller_files[0], controller_files[1])