66 lines
2.1 KiB
Python

"""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 Pid
class TestPid(TestCase):
"""Test for correct runtime behaviour in pyrate.act.control.pid."""
# In this context, we reproduce a common PID notation
# pylint: disable=invalid-name
def setUp(self) -> None:
"""Setup 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.dt = 0.5
# State and target
# Target is already reached in this example
self.state = vstack([0.0])
self.state_derivative = vstack([0.0])
self.desired = vstack([0.0])
def test_process_tracking(self) -> None:
"""Assert that a pandas.DataFrame with process data is created."""
# Initialize PID controller
pid = Pid(self.P, self.I, self.D, self.dt, keep_trace=True)
# 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 get lower."
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"