diff --git a/urdf_parser_py/src/urdf_parser_py/urdf.py b/urdf_parser_py/src/urdf_parser_py/urdf.py
index b0fceb02..615aa197 100644
--- a/urdf_parser_py/src/urdf_parser_py/urdf.py
+++ b/urdf_parser_py/src/urdf_parser_py/urdf.py
@@ -224,8 +224,8 @@ def __init__(self, rising=None, falling=None):
 		self.falling = falling
 
 xmlr.reflect(JointCalibration, params = [
-	xmlr.Attribute('rising', float),
-	xmlr.Attribute('falling', float)
+	xmlr.Attribute('rising', float, False),
+	xmlr.Attribute('falling', float, False)
 	])
 
 class JointLimit(xmlr.Object):
@@ -237,8 +237,8 @@ def __init__(self, effort=None, velocity=None, lower=None, upper=None):
 
 xmlr.reflect(JointLimit, params = [
 	xmlr.Attribute('effort', float),
-	xmlr.Attribute('lower', float),
-	xmlr.Attribute('upper', float),
+	xmlr.Attribute('lower', float, False, 0),
+	xmlr.Attribute('upper', float, False, 0),
 	xmlr.Attribute('velocity', float)
 	])
 
@@ -264,9 +264,9 @@ def __init__(self, velocity=None, position=None, lower=None, upper=None):
 
 xmlr.reflect(SafetyController, params = [
 	xmlr.Attribute('k_velocity', float),
-	xmlr.Attribute('k_position', float),
-	xmlr.Attribute('soft_lower_limit', float),
-	xmlr.Attribute('soft_upper_limit', float)
+	xmlr.Attribute('k_position', float, False, 0),
+	xmlr.Attribute('soft_lower_limit', float, False, 0),
+	xmlr.Attribute('soft_upper_limit', float, False, 0)
 	])
 
 class Joint(xmlr.Object):
@@ -329,22 +329,164 @@ def __init__(self, name=None, visual=None, inertial=None, collision=None, origin
 	])
 
 
+class Actuator(xmlr.Object):
+	def __init__(self, name = None, hardwareInterface = None, mechanicalReduction = 1):
+		self.name = name
+		self.hardwareInterface = None
+		self.mechanicalReduction = None
+
+xmlr.reflect(Actuator, tag = 'actuator', params = [
+		name_attribute,
+		xmlr.Element('hardwareInterface', str),
+		xmlr.Element('mechanicalReduction', float, required = False)
+		])
+
 class Transmission(xmlr.Object):
-	def __init__(self, name = None, joint = None, actuator = None, type = None, mechanicalReduction = 1):
+	def __init__(self, name = None, joint = None, actuator = None, mechanicalReduction = None):
+		self.name = name
+		self.joint = joint
+		self.actuator = actuator
+
+xmlr.reflect(Transmission, tag = 'new_transmission', params = [
+	name_attribute,
+	xmlr.Attribute('type', str),
+	xmlr.Element('joint', 'element_name'),
+	xmlr.Element('actuator', Actuator),
+	])
+
+class PR2Compensator(xmlr.Object):
+	def __init__(self, k_belt=4000.0, kd_motor=10.0, lambda_combined=0.0, lambda_joint=60.0, lambda_motor=60.0, mass_motor=0.05):
+		self.k_belt = k_belt
+		self.kd_motor = kd_motor
+		self.lambda_combined = lambda_combined
+		self.lambda_joint = lambda_joint
+		self.lambda_motor = lambda_motor
+		self.mass_motor = mass_motor
+
+xmlr.reflect(PR2Compensator, tag = 'compensator', params = [
+		xmlr.Attribute('k_belt', float),
+		xmlr.Attribute('kd_motor', float),
+		xmlr.Attribute('lambda_combined', float),
+		xmlr.Attribute('lambda_joint', float),
+		xmlr.Attribute('lambda_motor', float),
+		xmlr.Attribute('mass_motor', float)
+		])
+
+class PR2SimulatedActuatedJoint(xmlr.Object):
+	def __init__(self, name = None, simulated_reduction = 3000, passive_actuated_joint = None):
+		self.name = name
+		self.simulated_reduction = simulated_reduction
+		self.passive_actuated_joint = passive_actuated_joint
+
+xmlr.reflect(PR2SimulatedActuatedJoint, tag = 'simulated_actuated_joint', params = [
+		name_attribute,
+		xmlr.Attribute('simulated_reduction', float),
+		xmlr.Attribute('passive_actuated_joint', str, False)
+		])
+
+class PR2Transmission(xmlr.Object):
+	def __init__(self, name = None, joint = None, actuator = None, mechanicalReduction = None, compensator = None, simulated_actuated_joint = None):
 		self.name = name
-		self.type = type
 		self.joint = joint
 		self.actuator = actuator
 		self.mechanicalReduction = mechanicalReduction
+		self.compensator = compensator
+		self.simulated_actuated_joint = simulated_actuated_joint
 
-xmlr.reflect(Transmission, tag = 'transmission', params = [
+xmlr.reflect(PR2Transmission, tag = 'pr2_transmission', params = [
 	name_attribute,
 	xmlr.Attribute('type', str),
 	xmlr.Element('joint', 'element_name'),
 	xmlr.Element('actuator', 'element_name'),
-	xmlr.Element('mechanicalReduction', float)
+	xmlr.Element('mechanicalReduction', float),
+	xmlr.Element('compensator', PR2Compensator, False),
+	xmlr.Element('simulated_actuated_joint', PR2SimulatedActuatedJoint, False)
+	])
+
+class PR2Actuator(xmlr.Object):
+	def __init__(self, name = None, mechanicalReduction = 1):
+		self.name = name
+		self.mechanicalReduction = mechanicalReduction
+
+xmlr.reflect(PR2Actuator, tag = 'pr2_actuator', params = [
+	name_attribute,
+	xmlr.Attribute('mechanicalReduction', float)
+	])
+
+class PR2WristTransmission(xmlr.Object):
+	def __init__(self, name = None, type = None, rightActuator = None, leftActuator = None, flexJoint = None, rollJoint = None):
+		self.name = name
+		self.type = type
+                self.rightActuator = rightActuator
+                self.leftActuator = leftActuator
+                self.flexJoint = flexJoint
+                self.rollJoint = rollJoint
+
+xmlr.reflect(PR2WristTransmission, tag = 'pr2_wrist_transmission', params = [
+	name_attribute,
+	xmlr.Attribute('type', str),
+	xmlr.Element('rightActuator', PR2Actuator),
+	xmlr.Element('leftActuator', PR2Actuator),
+	xmlr.Element('flexJoint', PR2Actuator),
+	xmlr.Element('rollJoint', PR2Actuator)
+	])
+
+
+class PR2GapJoint(xmlr.Object):
+	def __init__(self, L0=0.0, a=0.0, b=0.0, gear_ratio=40.0, h=0.0, mechanical_reduction=1.0, name=None, phi0=0.5, r=0.0, screw_reduction=0.0, t0=0.0, theta0=0.0):
+		self.L0 = L0
+		self.a = a
+		self.b = b
+		self.gear_ratio = gear_ratio
+		self.h = h
+		self.mechanical_reduction = mechanical_reduction
+		self.name = name
+		self.phi0 = phi0
+		self.r = r
+		self.screw_reduction = screw_reduction
+		self.t0 = t0
+		self.theta0 = theta0
+
+xmlr.reflect(PR2GapJoint, tag = 'pr2_gap_joint', params = [
+		xmlr.Attribute('L0', float),
+		xmlr.Attribute('a', float),
+		xmlr.Attribute('b', float),
+		xmlr.Attribute('gear_ratio', float),
+		xmlr.Attribute('h', float),
+		xmlr.Attribute('mechanical_reduction', float),
+		xmlr.Attribute('name', str),
+		xmlr.Attribute('phi0', float),
+		xmlr.Attribute('r', float),
+		xmlr.Attribute('screw_reduction', float),
+		xmlr.Attribute('t0', float),
+		xmlr.Attribute('theta0', float)
+		])
+
+class PR2GripperTransmission(xmlr.Object):
+	def __init__(self, name = None, type = None, actuator  = None, gap_joint = None, use_simulated_gripper_joint = None, passive_joint = [], simulated_actuated_joint = None):
+		self.aggregate_init()
+		self.name = name
+		self.type = type
+                self.actuator = actuator
+                self.gap_joint = gap_joint
+                self.use_simulated_gripper_joint = use_simulated_gripper_joint
+                self.passive_joint = passive_joint
+                self.simulated_actuated_joint = simulated_actuated_joint
+
+xmlr.reflect(PR2GripperTransmission, tag = 'pr2_gripper_transmission', params = [
+	name_attribute,
+	xmlr.Attribute('type', str),
+	xmlr.Element('actuator', 'element_name'),
+	xmlr.Element('gap_joint', PR2GapJoint),
+	xmlr.Element('use_simulated_gripper_joint', 'element_name'),
+	xmlr.AggregateElement('passive_joint', 'element_name', 'passive_joint'),
+	xmlr.Element('simulated_actuated_joint', PR2SimulatedActuatedJoint),
 	])
 
+#xmlr.add_type('transmission', xmlr.DuckTypedFactory('transmission', [Transmission, PR2WristTransmission, PR2GripperTransmission]))
+xmlr.add_type('transmission', xmlr.DuckTypedFactory('transmission', [Transmission, PR2Transmission, PR2WristTransmission, PR2GripperTransmission]))
+
+
 class Robot(xmlr.Object):
 	def __init__(self, name = None):
 		self.aggregate_init()
@@ -426,11 +568,11 @@ def from_parameter_server(cls, key = 'robot_description'):
 	xmlr.AggregateElement('link', Link),
 	xmlr.AggregateElement('joint', Joint),
 	xmlr.AggregateElement('gazebo', xmlr.RawType()),
- 	xmlr.AggregateElement('transmission', Transmission),
+	xmlr.AggregateElement('transmission', 'transmission'),
 	xmlr.AggregateElement('material', Material)
 	])
 
 # Make an alias
 URDF = Robot
 
-xmlr.end_namespace()
\ No newline at end of file
+xmlr.end_namespace()
diff --git a/urdf_parser_py/src/urdf_parser_py/xml_reflection/core.py b/urdf_parser_py/src/urdf_parser_py/xml_reflection/core.py
index d463a1a8..99545d37 100644
--- a/urdf_parser_py/src/urdf_parser_py/xml_reflection/core.py
+++ b/urdf_parser_py/src/urdf_parser_py/xml_reflection/core.py
@@ -194,6 +194,28 @@ def write_xml(self, node, obj):
 		obj.write_xml(node)
 
 
+class DuckTypedFactory(ValueType):
+        def __init__(self, name, typeOrder):
+                self.name = name
+                assert len(typeOrder) > 0
+                self.type_order = typeOrder
+
+        def from_xml(self, node):
+                error_set = []
+                for value_type in self.type_order:
+                        try:
+                                return value_type.from_xml(node)
+                        except Exception as e:
+                                error_set.append((value_type, e))
+                # Should have returned, we encountered errors
+                out = "Could not perform duck-typed parsing."
+                for (value_type, e) in error_set:
+                        out += "\nValue Type: {}\nException: {}\n".format(value_type, e)
+                raise Exception(out)
+
+        def write_xml(self, node, obj):
+                obj.write_xml(node)
+
 class Param(object):
 	""" Mirroring Gazebo's SDF api