Moved Drivetrain from y2017 python to frc971
Change-Id: If931cf988d2615acc286d288fc0e5c9e7e3a5b90
diff --git a/frc971/control_loops/python/drivetrain.py b/frc971/control_loops/python/drivetrain.py
new file mode 100644
index 0000000..5665fd9
--- /dev/null
+++ b/frc971/control_loops/python/drivetrain.py
@@ -0,0 +1,416 @@
+#!/usr/bin/python
+
+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 DrivetrainParams(object):
+ def __init__(self, J, mass, robot_radius, wheel_radius, G_high, G_low,
+ q_pos_low, q_pos_high, q_vel_low, q_vel_high,
+ motor_type = control_loop.CIM(), num_motors = 2, dt = 0.00505,
+ controller_poles=[0.90, 0.90], observer_poles=[0.02, 0.02]):
+ """Defines all constants of a drivetrain.
+
+ Args:
+ J: float, Moment of inertia of drivetrain in kg m^2
+ mass: float, Mass of the robot in kg.
+ robot_radius: float, Radius of the robot, in meters (requires tuning by
+ hand).
+ wheel_radius: float, Radius of the wheels, in meters.
+ G_high: float, Gear ratio for high gear.
+ G_low: float, Gear ratio for low gear.
+ dt: float, Control loop time step.
+ q_pos_low: float, q position low gear.
+ q_pos_high: float, q position high gear.
+ q_vel_low: float, q velocity low gear.
+ q_vel_high: float, q velocity high gear.
+ motor_type: object, class of values defining the motor in drivetrain.
+ num_motors: int, number of motors on one side of drivetrain.
+ controller_poles: array, An array of poles. (See control_loop.py)
+ observer_poles: array, An array of poles. (See control_loop.py)
+ """
+
+ self.J = J
+ self.mass = mass
+ self.robot_radius = robot_radius
+ self.wheel_radius = wheel_radius
+ self.G_high = G_high
+ self.G_low = G_low
+ self.dt = dt
+ self.q_pos_low = q_pos_low
+ self.q_pos_high = q_pos_high
+ self.q_vel_low = q_vel_low
+ self.q_vel_high = q_vel_high
+ self.motor_type = motor_type
+ self.num_motors = num_motors
+ self.controller_poles = controller_poles
+ self.observer_poles = observer_poles
+
+class Drivetrain(control_loop.ControlLoop):
+ def __init__(self, drivetrain_params, name="Drivetrain", left_low=True,
+ right_low=True):
+ """Defines a base drivetrain for a robot.
+
+ Args:
+ drivetrain_params: DrivetrainParams, class of values defining the drivetrain.
+ name: string, Name of this drivetrain.
+ left_low: bool, Whether the left is in high gear.
+ right_low: bool, Whether the right is in high gear.
+ """
+ super(Drivetrain, self).__init__(name)
+
+ # Moment of inertia of the drivetrain in kg m^2
+ self.J = drivetrain_params.J
+ # Mass of the robot, in kg.
+ self.mass = drivetrain_params.mass
+ # Radius of the robot, in meters (requires tuning by hand)
+ self.robot_radius = drivetrain_params.robot_radius
+ # Radius of the wheels, in meters.
+ self.r = drivetrain_params.wheel_radius
+
+ # Gear ratios
+ self.G_low = drivetrain_params.G_low
+ self.G_high = drivetrain_params.G_high
+ if left_low:
+ self.Gl = self.G_low
+ else:
+ self.Gl = self.G_high
+ if right_low:
+ self.Gr = self.G_low
+ else:
+ self.Gr = self.G_high
+
+ # Control loop time step
+ self.dt = drivetrain_params.dt
+
+ self.BuildDrivetrain(drivetrain_params.motor_type, drivetrain_params.num_motors);
+
+ if left_low or right_low:
+ q_pos = drivetrain_params.q_pos_low
+ q_vel = drivetrain_params.q_vel_low
+ else:
+ q_pos = drivetrain_params.q_pos_high
+ q_vel = drivetrain_params.q_vel_high
+
+ self.BuildDrivetrainController(q_pos, q_vel)
+
+ self.InitializeState()
+
+ def BuildDrivetrain(self, motor, num_motors_per_side):
+ self.motor = motor
+ # Number of motors per side
+ self.num_motors = num_motors_per_side
+ # Stall Torque in N m
+ self.stall_torque = motor.stall_torque * self.num_motors * 0.60
+ # Stall Current in Amps
+ self.stall_current = motor.stall_current * self.num_motors
+ # Free Speed in rad/s
+ self.free_speed = motor.free_speed
+ # Free Current in Amps
+ self.free_current = motor.free_current * self.num_motors
+
+ # Effective motor resistance in ohms.
+ self.resistance = 12.0 / self.stall_current
+
+ # Resistance of the motor, divided by the number of motors.
+ # 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
+
+ # These describe the way that a given side of a robot will be influenced
+ # by the other side. Units of 1 / kg.
+ self.msp = 1.0 / self.mass + self.robot_radius * self.robot_radius / self.J
+ self.msn = 1.0 / self.mass - self.robot_radius * self.robot_radius / self.J
+ # The calculations which we will need for A and B.
+ self.tcl = self.Kt / self.Kv / (self.Gl * self.Gl * self.resistance * self.r * self.r)
+ self.tcr = self.Kt / self.Kv / (self.Gr * self.Gr * self.resistance * self.r * self.r)
+ self.mpl = self.Kt / (self.Gl * self.resistance * self.r)
+ self.mpr = self.Kt / (self.Gr * self.resistance * self.r)
+
+ # State feedback matrices
+ # X will be of the format
+ # [[positionl], [velocityl], [positionr], velocityr]]
+ self.A_continuous = numpy.matrix(
+ [[0, 1, 0, 0],
+ [0, -self.msp * self.tcl, 0, -self.msn * self.tcr],
+ [0, 0, 0, 1],
+ [0, -self.msn * self.tcl, 0, -self.msp * self.tcr]])
+ self.B_continuous = numpy.matrix(
+ [[0, 0],
+ [self.msp * self.mpl, self.msn * self.mpr],
+ [0, 0],
+ [self.msn * self.mpl, self.msp * self.mpr]])
+ self.C = numpy.matrix([[1, 0, 0, 0],
+ [0, 0, 1, 0]])
+ self.D = numpy.matrix([[0, 0],
+ [0, 0]])
+
+ self.A, self.B = self.ContinuousToDiscrete(
+ self.A_continuous, self.B_continuous, self.dt)
+
+ def BuildDrivetrainController(self, q_pos, q_vel):
+ # Tune the LQR controller
+ self.Q = numpy.matrix([[(1.0 / (q_pos ** 2.0)), 0.0, 0.0, 0.0],
+ [0.0, (1.0 / (q_vel ** 2.0)), 0.0, 0.0],
+ [0.0, 0.0, (1.0 / (q_pos ** 2.0)), 0.0],
+ [0.0, 0.0, 0.0, (1.0 / (q_vel ** 2.0))]])
+
+ self.R = numpy.matrix([[(1.0 / (12.0 ** 2.0)), 0.0],
+ [0.0, (1.0 / (12.0 ** 2.0))]])
+ self.K = controls.dlqr(self.A, self.B, self.Q, self.R)
+
+ glog.debug('DT q_pos %f q_vel %s %s', q_pos, q_vel, self._name)
+ glog.debug(str(numpy.linalg.eig(self.A - self.B * self.K)[0]))
+ glog.debug('K %s', repr(self.K))
+
+ self.hlp = 0.3
+ self.llp = 0.4
+ self.PlaceObserverPoles([self.hlp, self.hlp, self.llp, self.llp])
+
+ self.U_max = numpy.matrix([[12.0], [12.0]])
+ self.U_min = numpy.matrix([[-12.0], [-12.0]])
+
+class KFDrivetrain(Drivetrain):
+ def __init__(self, drivetrain_params, name="KFDrivetrain",
+ left_low=True, right_low=True):
+ """Kalman filter values of a drivetrain.
+
+ Args:
+ drivetrain_params: DrivetrainParams, class of values defining the drivetrain.
+ name: string, Name of this drivetrain.
+ left_low: bool, Whether the left is in high gear.
+ right_low: bool, Whether the right is in high gear.
+ """
+ super(KFDrivetrain, self).__init__(drivetrain_params, name, left_low, right_low)
+
+ self.unaugmented_A_continuous = self.A_continuous
+ self.unaugmented_B_continuous = self.B_continuous
+
+ # The practical voltage applied to the wheels is
+ # V_left = U_left + left_voltage_error
+ #
+ # The states are
+ # [left position, left velocity, right position, right velocity,
+ # left voltage error, right voltage error, angular_error]
+ #
+ # The left and right positions are filtered encoder positions and are not
+ # adjusted for heading error.
+ # The turn velocity as computed by the left and right velocities is
+ # adjusted by the gyro velocity.
+ # The angular_error is the angular velocity error between the wheel speed
+ # and the gyro speed.
+ self.A_continuous = numpy.matrix(numpy.zeros((7, 7)))
+ self.B_continuous = numpy.matrix(numpy.zeros((7, 2)))
+ self.A_continuous[0:4,0:4] = self.unaugmented_A_continuous
+ self.A_continuous[0:4,4:6] = self.unaugmented_B_continuous
+ self.B_continuous[0:4,0:2] = self.unaugmented_B_continuous
+ self.A_continuous[0,6] = 1
+ self.A_continuous[2,6] = -1
+
+ self.A, self.B = self.ContinuousToDiscrete(
+ self.A_continuous, self.B_continuous, self.dt)
+
+ self.C = numpy.matrix([[1, 0, 0, 0, 0, 0, 0],
+ [0, 0, 1, 0, 0, 0, 0],
+ [0, -0.5 / drivetrain_params.robot_radius, 0, 0.5 / drivetrain_params.robot_radius, 0, 0, 0]])
+
+ self.D = numpy.matrix([[0, 0],
+ [0, 0],
+ [0, 0]])
+
+ q_pos = 0.05
+ q_vel = 1.00
+ q_voltage = 10.0
+ q_encoder_uncertainty = 2.00
+
+ self.Q = numpy.matrix([[(q_pos ** 2.0), 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+ [0.0, (q_vel ** 2.0), 0.0, 0.0, 0.0, 0.0, 0.0],
+ [0.0, 0.0, (q_pos ** 2.0), 0.0, 0.0, 0.0, 0.0],
+ [0.0, 0.0, 0.0, (q_vel ** 2.0), 0.0, 0.0, 0.0],
+ [0.0, 0.0, 0.0, 0.0, (q_voltage ** 2.0), 0.0, 0.0],
+ [0.0, 0.0, 0.0, 0.0, 0.0, (q_voltage ** 2.0), 0.0],
+ [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, (q_encoder_uncertainty ** 2.0)]])
+
+ r_pos = 0.0001
+ r_gyro = 0.000001
+ self.R = numpy.matrix([[(r_pos ** 2.0), 0.0, 0.0],
+ [0.0, (r_pos ** 2.0), 0.0],
+ [0.0, 0.0, (r_gyro ** 2.0)]])
+
+ # Solving for kf gains.
+ self.KalmanGain, self.Q_steady = controls.kalman(
+ A=self.A, B=self.B, C=self.C, Q=self.Q, R=self.R)
+
+ self.L = self.A * self.KalmanGain
+
+ unaug_K = self.K
+
+ # Implement a nice closed loop controller for use by the closed loop
+ # controller.
+ self.K = numpy.matrix(numpy.zeros((self.B.shape[1], self.A.shape[0])))
+ self.K[0:2, 0:4] = unaug_K
+ self.K[0, 4] = 1.0
+ self.K[1, 5] = 1.0
+
+ self.Qff = numpy.matrix(numpy.zeros((4, 4)))
+ qff_pos = 0.005
+ qff_vel = 1.00
+ self.Qff[0, 0] = 1.0 / qff_pos ** 2.0
+ self.Qff[1, 1] = 1.0 / qff_vel ** 2.0
+ self.Qff[2, 2] = 1.0 / qff_pos ** 2.0
+ self.Qff[3, 3] = 1.0 / qff_vel ** 2.0
+ self.Kff = numpy.matrix(numpy.zeros((2, 7)))
+ self.Kff[0:2, 0:4] = controls.TwoStateFeedForwards(self.B[0:4,:], self.Qff)
+
+ self.InitializeState()
+
+
+def WriteDrivetrain(drivetrain_files, kf_drivetrain_files, year_namespace,
+ drivetrain_params):
+
+ # Write the generated constants out to a file.
+ drivetrain_low_low = Drivetrain(name="DrivetrainLowLow",
+ left_low=True, right_low=True, drivetrain_params=drivetrain_params)
+ drivetrain_low_high = Drivetrain(name="DrivetrainLowHigh",
+ left_low=True, right_low=False, drivetrain_params=drivetrain_params)
+ drivetrain_high_low = Drivetrain(name="DrivetrainHighLow",
+ left_low=False, right_low=True, drivetrain_params=drivetrain_params)
+ drivetrain_high_high = Drivetrain(name="DrivetrainHighHigh",
+ left_low=False, right_low=False, drivetrain_params=drivetrain_params)
+
+ kf_drivetrain_low_low = KFDrivetrain(name="KFDrivetrainLowLow",
+ left_low=True, right_low=True, drivetrain_params=drivetrain_params)
+ kf_drivetrain_low_high = KFDrivetrain(name="KFDrivetrainLowHigh",
+ left_low=True, right_low=False, drivetrain_params=drivetrain_params)
+ kf_drivetrain_high_low = KFDrivetrain(name="KFDrivetrainHighLow",
+ left_low=False, right_low=True, drivetrain_params=drivetrain_params)
+ kf_drivetrain_high_high = KFDrivetrain(name="KFDrivetrainHighHigh",
+ left_low=False, right_low=False, drivetrain_params=drivetrain_params)
+
+ namespaces = [year_namespace, 'control_loops', 'drivetrain']
+ dog_loop_writer = control_loop.ControlLoopWriter(
+ "Drivetrain", [drivetrain_low_low, drivetrain_low_high,
+ drivetrain_high_low, drivetrain_high_high],
+ namespaces = namespaces)
+ dog_loop_writer.AddConstant(control_loop.Constant("kDt", "%f",
+ drivetrain_low_low.dt))
+ dog_loop_writer.AddConstant(control_loop.Constant("kStallTorque", "%f",
+ drivetrain_low_low.stall_torque))
+ dog_loop_writer.AddConstant(control_loop.Constant("kStallCurrent", "%f",
+ drivetrain_low_low.stall_current))
+ dog_loop_writer.AddConstant(control_loop.Constant("kFreeSpeed", "%f",
+ drivetrain_low_low.free_speed))
+ dog_loop_writer.AddConstant(control_loop.Constant("kFreeCurrent", "%f",
+ drivetrain_low_low.free_current))
+ dog_loop_writer.AddConstant(control_loop.Constant("kJ", "%f",
+ drivetrain_low_low.J))
+ dog_loop_writer.AddConstant(control_loop.Constant("kMass", "%f",
+ drivetrain_low_low.mass))
+ dog_loop_writer.AddConstant(control_loop.Constant("kRobotRadius", "%f",
+ drivetrain_low_low.robot_radius))
+ dog_loop_writer.AddConstant(control_loop.Constant("kWheelRadius", "%f",
+ drivetrain_low_low.r))
+ dog_loop_writer.AddConstant(control_loop.Constant("kR", "%f",
+ drivetrain_low_low.resistance))
+ dog_loop_writer.AddConstant(control_loop.Constant("kV", "%f",
+ drivetrain_low_low.Kv))
+ dog_loop_writer.AddConstant(control_loop.Constant("kT", "%f",
+ drivetrain_low_low.Kt))
+ dog_loop_writer.AddConstant(control_loop.Constant("kLowGearRatio", "%f",
+ drivetrain_low_low.G_low))
+ dog_loop_writer.AddConstant(control_loop.Constant("kHighGearRatio", "%f",
+ drivetrain_high_high.G_high))
+ dog_loop_writer.AddConstant(control_loop.Constant("kHighOutputRatio", "%f",
+ drivetrain_high_high.G_high * drivetrain_high_high.r))
+
+ dog_loop_writer.Write(drivetrain_files[0], drivetrain_files[1])
+
+ kf_loop_writer = control_loop.ControlLoopWriter(
+ "KFDrivetrain", [kf_drivetrain_low_low, kf_drivetrain_low_high,
+ kf_drivetrain_high_low, kf_drivetrain_high_high],
+ namespaces = namespaces)
+ kf_loop_writer.Write(kf_drivetrain_files[0], kf_drivetrain_files[1])
+
+def PlotDrivetrainMotions(drivetrain_params):
+ # Simulate the response of the system to a step input.
+ drivetrain = Drivetrain(left_low=False, right_low=False, drivetrain_params=drivetrain_params)
+ simulated_left = []
+ simulated_right = []
+ for _ in xrange(100):
+ drivetrain.Update(numpy.matrix([[12.0], [12.0]]))
+ simulated_left.append(drivetrain.X[0, 0])
+ simulated_right.append(drivetrain.X[2, 0])
+
+ pylab.rc('lines', linewidth=4)
+ pylab.plot(range(100), simulated_left, label='left position')
+ pylab.plot(range(100), simulated_right, 'r--', label='right position')
+ pylab.suptitle('Acceleration Test\n12 Volt Step Input')
+ pylab.legend(loc='lower right')
+ pylab.show()
+
+ # Simulate forwards motion.
+ drivetrain = Drivetrain(left_low=False, right_low=False, drivetrain_params=drivetrain_params)
+ close_loop_left = []
+ close_loop_right = []
+ left_power = []
+ right_power = []
+ R = numpy.matrix([[1.0], [0.0], [1.0], [0.0]])
+ for _ in xrange(300):
+ U = numpy.clip(drivetrain.K * (R - drivetrain.X_hat),
+ drivetrain.U_min, drivetrain.U_max)
+ drivetrain.UpdateObserver(U)
+ drivetrain.Update(U)
+ close_loop_left.append(drivetrain.X[0, 0])
+ close_loop_right.append(drivetrain.X[2, 0])
+ left_power.append(U[0, 0])
+ right_power.append(U[1, 0])
+
+ pylab.plot(range(300), close_loop_left, label='left position')
+ pylab.plot(range(300), close_loop_right, 'm--', label='right position')
+ pylab.plot(range(300), left_power, label='left power')
+ pylab.plot(range(300), right_power, '--', label='right power')
+ pylab.suptitle('Linear Move\nLeft and Right Position going to 1')
+ pylab.legend()
+ pylab.show()
+
+ # Try turning in place
+ drivetrain = Drivetrain(drivetrain_params=drivetrain_params)
+ close_loop_left = []
+ close_loop_right = []
+ R = numpy.matrix([[-1.0], [0.0], [1.0], [0.0]])
+ for _ in xrange(200):
+ U = numpy.clip(drivetrain.K * (R - drivetrain.X_hat),
+ drivetrain.U_min, drivetrain.U_max)
+ drivetrain.UpdateObserver(U)
+ drivetrain.Update(U)
+ close_loop_left.append(drivetrain.X[0, 0])
+ close_loop_right.append(drivetrain.X[2, 0])
+
+ pylab.plot(range(200), close_loop_left, label='left position')
+ pylab.plot(range(200), close_loop_right, label='right position')
+ pylab.suptitle('Angular Move\nLeft position going to -1 and right position going to 1')
+ pylab.legend(loc='center right')
+ pylab.show()
+
+ # Try turning just one side.
+ drivetrain = Drivetrain(drivetrain_params=drivetrain_params)
+ close_loop_left = []
+ close_loop_right = []
+ R = numpy.matrix([[0.0], [0.0], [1.0], [0.0]])
+ for _ in xrange(300):
+ U = numpy.clip(drivetrain.K * (R - drivetrain.X_hat),
+ drivetrain.U_min, drivetrain.U_max)
+ drivetrain.UpdateObserver(U)
+ drivetrain.Update(U)
+ close_loop_left.append(drivetrain.X[0, 0])
+ close_loop_right.append(drivetrain.X[2, 0])
+
+ pylab.plot(range(300), close_loop_left, label='left position')
+ pylab.plot(range(300), close_loop_right, label='right position')
+ pylab.suptitle('Pivot\nLeft position not changing and right position going to 1')
+ pylab.legend(loc='center right')
+ pylab.show()