Added shooter loop.

Still needs to actually be tested and tuned on a robot. Passes all of its tests.
diff --git a/frc971/control_loops/python/shooter.py b/frc971/control_loops/python/shooter.py
new file mode 100755
index 0000000..ab7b163
--- /dev/null
+++ b/frc971/control_loops/python/shooter.py
@@ -0,0 +1,119 @@
+#!/usr/bin/python
+
+import numpy
+import sys
+from matplotlib import pylab
+import control_loop
+
+class Shooter(control_loop.ControlLoop):
+  def __init__(self):
+    super(Shooter, self).__init__("Shooter")
+    # Stall Torque in N m
+    self.stall_torque = 0.49819248 
+    # Stall Current in Amps
+    self.stall_current = 85 
+    # Free Speed in RPM
+    self.free_speed = 19300.0 
+    # Free Current in Amps
+    self.free_current = 1.4
+    # Moment of inertia of the shooter wheel in kg m^2
+    self.J = 0.00161906
+    # Resistance of the motor, divided by 2 to account for the 2 motors
+    self.R = 12.0 / self.stall_current / 2
+    # Motor velocity constant
+    self.Kv = ((self.free_speed / 60.0 * 2.0 * numpy.pi) / 
+              (12.0 - self.R * self.free_current))
+    # Torque constant
+    self.Kt = self.stall_torque / self.stall_current
+    # Gear ratio
+    self.G = 11.0 / 34.0
+    # Control loop time step
+    self.dt = 0.01
+
+    # State feedback matrices
+    self.A_continuous = numpy.matrix( 
+        [[0, 1],
+         [0, -self.Kt / self.Kv / (self.J * self.G * self.G * self.R)]])
+    self.B_continuous = numpy.matrix( 
+        [[0],
+         [self.Kt / (self.J * self.G * self.R)]])
+    self.C = numpy.matrix([[1, 0]]) 
+    self.D = numpy.matrix([[0]]) 
+
+    self.ContinuousToDiscrete(self.A_continuous, self.B_continuous, 
+                              self.dt, self.C)
+
+    self.PlaceControllerPoles([.2, .15])
+
+    self.rpl = .45
+    self.ipl = 0.07
+    self.PlaceObserverPoles([self.rpl + 1j * self.ipl,
+                             self.rpl - 1j * self.ipl])
+
+    self.U_max = numpy.matrix([[12.0]])
+    self.U_min = numpy.matrix([[-12.0]])
+
+
+def main(argv):
+  # Simulate the response of the system to a step input.
+  shooter = Shooter()
+  simulated_x = []
+  for _ in xrange(500):
+    shooter.Update(numpy.matrix([[12.0]]))
+    simulated_x.append(shooter.X[0, 0])
+
+#  pylab.plot(range(500), simulated_x)
+#  pylab.show()
+
+  # Simulate the closed loop response of the system to a step input.
+  shooter = Shooter()
+  close_loop_x = []
+  close_loop_U = []
+  velocity_goal = 1050.0
+  R = numpy.matrix([[0.0], [velocity_goal]])
+  for _ in pylab.linspace(0,1.99,200):
+    # Iterate the position up.
+    R = numpy.matrix([[R[0, 0] + 10.5], [velocity_goal]])
+    # Prevents the position goal from going beyond what is necessary.
+    velocity_weight_scalar = 0.35
+    max_reference = ((shooter.U_max[0, 0] - velocity_weight_scalar *
+                    (velocity_goal - shooter.X_hat[1, 0]) * shooter.K[0, 1]) / shooter.K[0, 0]
+                    + shooter.X_hat[0, 0])
+    min_reference = ((shooter.U_min[0, 0] - velocity_weight_scalar *
+                    (velocity_goal - shooter.X_hat[1, 0]) * shooter.K[0, 1]) / shooter.K[0, 0]
+                    + shooter.X_hat[0, 0])
+    R[0, 0] = max(min(R[0, 0], max_reference), min_reference)
+    U = numpy.clip(shooter.K * (R - shooter.X_hat), shooter.U_min, shooter.U_max)
+    shooter.UpdateObserver(U)
+    shooter.Update(U)
+    close_loop_x.append(shooter.X[1, 0])
+    close_loop_U.append(U[0, 0])
+
+#  pylab.plotfile("shooter.csv", (0,1))
+#  pylab.plot(pylab.linspace(0,1.99,200), close_loop_U, 'ro')
+#  pylab.plotfile("shooter.csv", (0,2))
+  pylab.plot(pylab.linspace(0,1.99,200), close_loop_x, 'ro')
+  pylab.show()
+
+  # Simulate spin down.
+  spin_down_x = [];
+  R = numpy.matrix([[0.0], [0.0]])
+  for _ in xrange(150):
+    U = 0
+    shooter.UpdateObserver(U)
+    shooter.Update(U)
+    spin_down_x.append(shooter.X[1, 0])
+
+#  pylab.plot(range(150), spin_down_x)
+#  pylab.show()
+
+
+  if len(argv) != 3: 
+    print "Expected .cc file name and .h file name"
+  else:
+    shooter.DumpHeaderFile(argv[1])
+    shooter.DumpCppFile(argv[2], argv[1])
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))