PythonModels/systems/test_mql_mechanical.py

@@ -153,9 +153,17 @@ class TestMqlMechanicalMassState:
         return [self.velocity_m_s, self.displacement_m]
 
 
+@dataclass(frozen=True)
+class TestMqlMechanicalNodeKinematics:
+    alias: str
+    velocities_m_s: dict[int, float]
+    displacements_m: dict[int, float]
+
+
 @dataclass(frozen=True)
 class TestMqlMechanicalMassSnapshot:
     states: tuple[TestMqlMechanicalMassState, ...]
+    node_kinematics_by_alias: dict[str, TestMqlMechanicalNodeKinematics]
 
     @property
     def state_count(self) -> int:
@@ -186,7 +194,30 @@ class TestMqlMechanicalMassClosure:
             )
             for index, alias in enumerate(self.mass_aliases)
         )
-        return TestMqlMechanicalMassSnapshot(states=states)
+        return TestMqlMechanicalMassSnapshot(
+            states=states,
+            node_kinematics_by_alias=self._node_kinematics_by_alias(states),
+        )
+
+    def _node_kinematics_by_alias(
+        self,
+        states: tuple[TestMqlMechanicalMassState, ...],
+    ) -> dict[str, TestMqlMechanicalNodeKinematics]:
+        state_by_alias = {state.alias: state for state in states}
+        front = state_by_alias["mass_friction_endstops_18"]
+        rear = state_by_alias["mass_friction_endstops_19"]
+        return {
+            "dynamic_mechanical_node_alternative_2": TestMqlMechanicalNodeKinematics(
+                alias="dynamic_mechanical_node_alternative_2",
+                velocities_m_s={port: -front.velocity_m_s for port in range(1, 9)},
+                displacements_m={port: -front.displacement_m for port in range(1, 9)},
+            ),
+            "dynamic_mechanical_node_alternative_3": TestMqlMechanicalNodeKinematics(
+                alias="dynamic_mechanical_node_alternative_3",
+                velocities_m_s={port: rear.velocity_m_s for port in range(1, 9)},
+                displacements_m={port: rear.displacement_m for port in range(1, 9)},
+            ),
+        }
 
     def rhs(
         self,

tests/test_test_mql_mechanical.py

@@ -63,6 +63,31 @@ class TestMqlMechanicalAssemblyTests(unittest.TestCase):
         for index, mass_state in enumerate(snapshot.states):
             self.assertAlmostEqual(rhs[2 * index + 1], mass_state.velocity_m_s)
 
+    def test_mechanical_mass_snapshot_exposes_lmechan1_node_kinematics(self) -> None:
+        closure = TestMqlMechanicalMassClosure(self.assembly)
+        state = closure.initial_state_vector()
+        state[16] = 0.2
+        state[17] = 0.37
+        state[18] = -0.3
+        state[19] = -0.72
+
+        snapshot = closure.snapshot(state)
+        front = snapshot.node_kinematics_by_alias[
+            "dynamic_mechanical_node_alternative_2"
+        ]
+        rear = snapshot.node_kinematics_by_alias[
+            "dynamic_mechanical_node_alternative_3"
+        ]
+
+        self.assertEqual(set(front.velocities_m_s), set(range(1, 9)))
+        self.assertEqual(set(front.displacements_m), set(range(1, 9)))
+        self.assertEqual(set(rear.velocities_m_s), set(range(1, 9)))
+        self.assertEqual(set(rear.displacements_m), set(range(1, 9)))
+        self.assertAlmostEqual(front.velocities_m_s[1], -0.2)
+        self.assertAlmostEqual(front.displacements_m[8], -0.37)
+        self.assertAlmostEqual(rear.velocities_m_s[1], -0.3)
+        self.assertAlmostEqual(rear.displacements_m[8], -0.72)
+
     def test_system_simulates_mechanical_mass_state_closure(self) -> None:
         system = TestMqlSystem()