added tests and small improvements

Author: asteppke

examples/Examples.ipynb

@@ -16,6 +16,8 @@ classifiers = [
   "Programming Language :: Python"
 ]
 
+[tool.pytest.ini_options]
+pythonpath = ["."]
 
 # [project.urls]
 # Homepage = "https://example.com"

pyproject.toml

@@ -0,0 +1,29 @@
+import unittest
+from tinypid import PID
+
+class TestPID(unittest.TestCase):
+    def test_output_with_no_manual_output(self):
+        pid = PID(K_p=1.0, K_i=0.5, K_d=0.2, setpoint=10.0, dt=0.1)
+        process_variable = 8.0
+        expected_output = 6.1  # P = 1.0 * (10.0 - 8.0) = 2.0, I = 0.5 * (10.0 - 8.0) * 0.1 = 0.1, D = 0.2 * ((10.0 - 8.0) / 0.1) = 4
+        output = pid(process_variable)
+        self.assertAlmostEqual(output, expected_output)
+
+    def test_output_with_manual_output(self):
+        pid = PID(K_p=1.0, K_i=0.5, K_d=0.2, setpoint=10.0, dt=0.1)
+        process_variable = 8.0
+        manual_output = 5.0
+        expected_output = manual_output  # Since manual_output is provided, the output should be equal to it
+        output = pid(process_variable, manual_output=manual_output)
+        self.assertAlmostEqual(output, expected_output)
+
+    def test_output_with_anti_windup_disabled(self):
+        pid = PID(K_p=1.0, K_i=0.5, K_d=0.2, setpoint=10.0, dt=0.1)
+        process_variable = 8.0
+        manual_output = 15.0
+        expected_output = manual_output  # Since manual_output is provided, the output should be equal to it
+        output = pid(process_variable, manual_output=manual_output, anti_windup=False)
+        self.assertAlmostEqual(output, expected_output)
+
+if __name__ == '__main__':
+    unittest.main()

tests/test_pid.py

@@ -0,0 +1 @@
+from .pid import PID

tinypid/__init__.py

@@ -3,9 +3,9 @@
 A minimal PID controller. 
 
 Example usage:
-from tinypid import pid
+import tinypid 
 
-controller = pid.PID()
+controller = tinypid.PID()
 
 output = controller(10)
 
@@ -48,6 +48,8 @@ def __init__(
         """
         if dt <= 0:
             raise ValueError("Time step (dt) must be positive.")
+        if not 0 <= derivative_lowpass <= 1:
+            raise ValueError("derivative_lowpass must be between 0 and 1")
 
         self.K_p = K_p
         self.K_i = K_i
@@ -106,6 +108,19 @@ def limit(self, output: float) -> Tuple[bool, float]:
         saturated = output != unlimited
 
         return saturated, output
+    
+    def update_gains(self, K_p: float, K_i: float, K_d: float) -> None:
+        """
+        Update the PID gains.
+
+        Parameters:
+            K_p : The new proportional gain
+            K_i : The new integral gain
+            K_d : The new derivative gain
+        """
+        self.K_p = K_p
+        self.K_i = K_i
+        self.K_d = K_d
 
     def __call__(
         self, process_variable: float, manual_output: Optional[float] = None, anti_windup: bool = True