Removed the subdir.

pyrate/tests/act/test_lqr_integral.py

@@ -0,0 +1,117 @@
+"""This module asserts correct runtime behaviour of the pyrate.act.pid module."""
+
+# Test environment
+from unittest import TestCase
+
+# Mathematics
+from numpy import array
+from numpy import eye
+from numpy.linalg import eig
+from numpy import vstack
+
+# Package under test
+from pyrate.act.control import AntiWindupLqr
+
+
+class TestAntiWindupLqr(TestCase):
+
+    """Test for correct runtime behaviour in pyrate.act.control.anti_windup_lqr."""
+
+    # In this context, we reproduce a common controller notation
+    # pylint: disable=invalid-name
+
+    def setUp(self) -> None:
+        """Setup the LQR specification for testing."""
+
+        # Model specification
+        self.A = array([[0, 1], [0, 0]])
+        self.B = array([0, 1])[:, None]
+        self.C = array([1, 0])[None, :]
+        self.max_control = array([1.0])
+        self.dt = 0.5
+
+        # Time discrete model
+        self.Ad = self.dt * eye(2)
+        self.Bd = self.B + self.A @ self.B * self.dt
+
+        # Cost matrix specification
+        self.Q = eye(3)
+        self.R = array([[1.0]])
+
+        # State and target
+        # Target is already reached in this example
+        self.wrong_state = vstack([1.0, 0.0])
+        self.state_small_negative = vstack([-0.001, 0.0])
+        self.state = vstack([0.0, 0.0])
+        self.desired = vstack([0.0])
+        self.desired1 = vstack([1.0])
+
+    def test_lqr_design(self) -> None:
+        """Assert stable controller dynamics"""
+
+        # Initialize controller
+        lqr = AntiWindupLqr(
+            self.A, self.B, self.C, self.Q, self.R, self.max_control, self.dt, keep_trace=True
+        )
+        # check continous time eigen_values
+        eigen_values, _ = eig(lqr.A - lqr.B @ lqr.K)
+        assert all(ev.real < 0 for ev in eigen_values), "instable controller"
+
+    def test_anti_windup(self) -> None:
+        """Assert control signal in allowed range, LQR responsive by limited integral part."""
+
+        # Initialize controller
+        lqr = AntiWindupLqr(
+            self.A, self.B, self.C, self.Q, self.R, self.max_control, self.dt, keep_trace=True
+        )
+
+        # Execute a few control steps
+        for _ in range(10):
+            control_signal = lqr.control(desired=self.desired, state=self.wrong_state)
+            assert abs(control_signal) <= self.max_control, "control limits are not applied"
+
+        assert control_signal == -self.max_control, f"control limits not reached {control_signal}"
+
+        # test stationary summed error
+        summed_error = lqr.summed_error
+        control_signal = lqr.control(desired=self.desired, state=self.wrong_state)
+        assert abs(lqr.summed_error - summed_error) < 1e-6, "summed error changes in saturation"
+
+        # test reactiveness
+        control_signal_back = lqr.control(desired=self.desired, state=self.state_small_negative)
+        assert abs(control_signal_back) < self.max_control, "anti wind up is not working"
+
+    def test_process_tracking(self) -> None:
+        """Assert useful controller behavior and that a pandas.DataFrame with process data is created."""
+
+        # Initialize controller
+        lqr = AntiWindupLqr(
+            self.A, self.B, self.C, self.Q, self.R, self.max_control, self.dt, keep_trace=True
+        )
+
+        # Check zero control
+        control_signal = lqr.control(desired=self.desired, state=self.state)
+        assert control_signal == 0, "Control signal not zero when desired value 0 reached"
+        control_signal = lqr.control(desired=self.desired1, state=self.wrong_state)
+        assert control_signal == 0, "Control signal not zero when desired value 0 reached"
+        lqr.reset()
+
+        # Execute a few control steps
+        state = self.wrong_state.copy()
+        initial_error = abs(self.C @ state - self.desired)
+        for _ in range(10):
+            control_signal = lqr.control(desired=self.desired, state=state)
+            state = self.Ad.dot(state) + self.Bd.dot(control_signal)
+            error = abs(self.C @ state - self.desired)
+            assert error < initial_error or error == 0, "Error exceeds initial - instable controller?"
+
+        # Assert correct process tracing with LQR controller
+        assert lqr.process is not None, "LQR did not keep trace of process"
+        assert len(lqr.process.index) == 10, "LQR has not traced enough steps"
+
+        # Reset controller
+        lqr.reset()
+
+        # Assert correct reset to initial state
+        assert lqr.summed_error == 0.0, "Integral did not reset summed error properly"
+        assert len(lqr.process.index) == 0, "LQR has not dropped process trace properly"