adding a filter to derivative term #44
Description
👋 what are your thoughts on allowing users to add a hook into the class to add a filter infront of the derivative term. I've read in a few places that adding a filter infront of the derivative term is a good idea (i.e. instead of passing the raw input_ to d_input, we pass in some filtered version).
High level:
def my_filter(input_, previous_input_):
# compute things
return some_float
pid = PID(...)
pid.add_derivative_hook(my_filter)low level:
def _compute_derivative(self, input, last_input):
return input - (last_input if (last_input is not None) else input)
def add_derivative_hook(self, callable):
self._compute_derivative = callable
def __call__(...):
...
# Compute error terms
error = self.setpoint - input_
d_input = self._compute_derivative(input, self._last_input)
...