Updated drivetrain code to include a CIM model.
diff --git a/frc971/control_loops/python/drivetrain.py b/frc971/control_loops/python/drivetrain.py
index ed180d8..fe20228 100755
--- a/frc971/control_loops/python/drivetrain.py
+++ b/frc971/control_loops/python/drivetrain.py
@@ -5,6 +5,49 @@
import sys
from matplotlib import pylab
+
+class CIM(control_loop.ControlLoop):
+ def __init__(self):
+ super(CIM, self).__init__("CIM")
+ # Stall Torque in N m
+ self.stall_torque = 2.42
+ # Stall Current in Amps
+ self.stall_current = 133
+ # Free Speed in RPM
+ self.free_speed = 4650.0
+ # Free Current in Amps
+ self.free_current = 2.7
+ # Moment of inertia of the CIM in kg m^2
+ self.J = 0.0001
+ # Resistance of the motor, divided by 2 to account for the 2 motors
+ self.R = 12.0 / self.stall_current
+ # 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
+ # Control loop time step
+ self.dt = 0.01
+
+ # State feedback matrices
+ self.A_continuous = numpy.matrix(
+ [[-self.Kt / self.Kv / (self.J * self.R)]])
+ self.B_continuous = numpy.matrix(
+ [[self.Kt / (self.J * self.R)]])
+ 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([0.01])
+
+ self.U_max = numpy.matrix([[12.0]])
+ self.U_min = numpy.matrix([[-12.0]])
+
+ self.InitializeState()
+
+
class Drivetrain(control_loop.ControlLoop):
def __init__(self, left_low=True, right_low=True):
super(Drivetrain, self).__init__("Drivetrain")
@@ -26,7 +69,7 @@
# Radius of the wheels, in meters.
self.r = .04445
# Resistance of the motor, divided by the number of motors.
- self.R = 12.0 / self.stall_current / 6 + 0.03
+ self.R = (12.0 / self.stall_current / 4 + 0.03) / (0.93 ** 2.0)
# Motor velocity constant
self.Kv = ((self.free_speed / 60.0 * 2.0 * numpy.pi) /
(12.0 - self.R * self.free_current))