Removed the subdir.

pyrate/tests/act/test_pid_anti_windup.py

@@ -0,0 +1,88 @@
+"""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 Inf
+from numpy.linalg import norm
+from numpy import vstack
+
+# Package under test
+from pyrate.act.control import AntiWindupPid
+
+
+class TestAntiWindupPid(TestCase):
+
+    """Test for correct runtime behaviour in pyrate.act.control.anti_windup_pid."""
+
+    # In this context, we reproduce a common PID notation
+    # pylint: disable=invalid-name
+
+    def setUp(self) -> None:
+        """Set up the PID specification for testing."""
+
+        # PID specification
+        self.P = array([[1.0]])
+        self.I = array([[1.0]])  # noqa: 741
+        self.D = array([[1.0]])
+        self.max_control = 1.0
+        self.dt = 0.5
+
+        # State and target
+        # Target is already reached in this example
+        self.state = vstack([0.0])
+        self.state_large = vstack([0.5])
+        self.state_small_neg = vstack([-0.01])
+        self.state_derivative = vstack([0.0])
+        self.desired = vstack([0.0])
+
+    def test_anti_windup(self) -> None:
+        """Assert control signal in allowed range, PID responsive by limited integral part."""
+        # Initialize PID controller
+        pid = AntiWindupPid(self.P, self.I, self.D, self.max_control, self.dt, keep_trace=True)
+
+        # Execute a few control steps
+        for _ in range(10):
+            control_signal = pid.control(
+                desired=self.desired, state=self.state_large, state_derivative=self.state_derivative
+            )
+            assert abs(control_signal) <= self.max_control, "control limits are not applied"
+        assert abs(control_signal) == self.max_control, "control limits not reached"
+
+        # test reactiveness
+        control_signal_back = pid.control(
+            desired=self.desired, state=self.state_small_neg, state_derivative=self.state_derivative
+        )
+        assert abs(control_signal_back) < self.max_control + 1e-4, "anti wind up is not working"
+
+    def test_process_tracking(self) -> None:
+        """Assert that a pandas.DataFrame with process data is created."""
+
+        # Initialize PID controller
+        pid = AntiWindupPid(self.P, self.I, self.D, self.max_control, self.dt, keep_trace=True)
+
+        # Execute a few control steps
+        # Execute a few control steps
+        state = self.state.copy()
+        previous_error = Inf
+        for _ in range(10):
+            control_signal = pid.control(
+                desired=self.desired, state=self.state, state_derivative=self.state_derivative
+            )
+            state += control_signal
+            error = norm(state - self.desired).item()  # Convert from numpy scalar to Python float
+            assert error < previous_error or error == 0, "Error did not decrease"
+            previous_error = error
+
+        # Assert correct process tracing with PID controller
+        assert pid.process is not None, "PID did not keep trace of process"
+        assert len(pid.process.index) == 10, "PID has not traced enough steps"
+
+        # Reset PID
+        pid.reset()
+
+        # Assert correct reset to initial state
+        assert pid.summed_error == 0.0, "PID did not reset summed error properly"
+        assert len(pid.process.index) == 0, "PID has not dropped process trace properly"