aerationcontrol ¶

Sensor ¶

Sensor(num, den, min_value, max_value, std)

Sensor class for simulating the response of a system to an input signal.

Parameters:

Name	Type	Description	Default
`num`	`array - like`	Numerator coefficients of the transfer function.	required
`den`	`array - like`	Denominator coefficients of the transfer function.	required
`min_value`	`float`	Minimum output value.	required
`max_value`	`float`	Maximum output value.	required
`std`	`float`	Standard deviation of the noise.	required

Source code in src/bsm2_python/bsm2/aerationcontrol.py

def __init__(
    self,
    num: float | np.ndarray | list[float],
    den: float | np.ndarray | list[float],
    min_value: float,
    max_value: float,
    std: float,
):
    self.num = num
    self.den = den
    self.min_value = min_value
    self.max_value = max_value
    self.std = std
    self.state_space = ct.tf2ss(num, den)
    n_states = self.state_space.nstates
    self.state = np.zeros(n_states)

PID ¶

PID(k, t_i, t_d, t_t, offset, min_value, max_value, setpoint, aw_init=None, *, use_antiwindup=True)

PID controller with anti-windup.

Parameters:

Name	Type	Description	Default
`k`	`float`	Proportional gain.	required
`t_i`	`float`	Integral time constant.	required
`t_d`	`float`	Derivative time constant.	required
`t_t`	`float`	Anti-windup time constant.	required
`offset`	`float`	Offset value.	required
`min_value`	`float`	Minimum output value.	required
`max_value`	`float`	Maximum output value.	required
`setpoint`	`float`	Desired setpoint.	required
`aw_init`	`float`	Initial anti-windup value. If not provided, it will be set to 0.	`None`
`use_antiwindup`	`bool`	If `True`, anti-windup is used. Default is `True`.	`True`

Source code in src/bsm2_python/bsm2/aerationcontrol.py

def __init__(
    self,
    k: float,
    t_i: float,
    t_d: float,
    t_t: float,
    offset: float,
    min_value: float,
    max_value: float,
    setpoint: float,
    aw_init: float | None = None,
    *,
    use_antiwindup: bool = True,
):
    self.k = k
    self.t_i = t_i
    self.t_d = t_d
    self.t_t = t_t
    self.offset = offset
    self.min_value = min_value
    self.max_value = max_value
    self.setpoint = setpoint
    self.integral = 0.0
    self.derivative = 0.0
    self.error = 0.0
    self.prev_error = 0.0
    self.prev_signal = 0.0
    self.prev_lim = 0.0
    self.aw = 0.0 if aw_init is None else aw_init
    self.use_antiwindup = use_antiwindup

output ¶

output(signal, dt, inject=0)

Calculate the control signal based on the PID controller.

Parameters:

Name	Type	Description	Default
`signal`	`float`	Input signal to the PID controller.	required
`dt`	`float`	Time step for the simulation.	required
`inject`	`float`	Additional signal to be injected into the control signal. Default is 0.	`0`

Source code in src/bsm2_python/bsm2/aerationcontrol.py

def output(self, signal: float, dt: float, inject: float = 0):
    """Calculate the control signal based on the PID controller.

    Parameters
    ----------
    signal : float
        Input signal to the PID controller.
    dt : float
        Time step for the simulation.
    inject : float, optional
        Additional signal to be injected into the control signal. Default is 0.
    """
    dt_arr = np.array([0, dt])
    self.error = self.k * (self.setpoint - signal)
    self.integral = self.error / self.t_i * (dt_arr[1] - dt_arr[0])
    self.derivative = self.k * self.t_d * (self.error - self.prev_error) / (dt_arr[1] - dt_arr[0])
    self.prev_error = self.error
    if self.use_antiwindup:
        self.aw = (self.prev_lim - self.prev_signal) / self.t_t * (dt_arr[1] - dt_arr[0])
    else:
        self.aw = 0
    control_signal = self.error + self.integral + self.derivative + self.offset + self.aw + inject
    self.prev_signal = control_signal
    control_signal = max(control_signal, self.min_value)
    control_signal = min(control_signal, self.max_value)
    self.prev_lim = control_signal
    return control_signal

Actuator ¶

Actuator(num, den)

Actuator class for simulating the response of a system to an input signal.

Parameters:

Name	Type	Description	Default
`num`	`array - like`	Numerator coefficients of the transfer function.	required
`den`	`array - like`	Denominator coefficients of the transfer function.	required

Source code in src/bsm2_python/bsm2/aerationcontrol.py

def __init__(self, num: float | np.ndarray | list[float], den: float | np.ndarray | list[float]):
    self.num = num
    self.den = den
    self.state_space = ct.tf2ss(num, den)
    n_states = self.state_space.nstates
    self.state = np.zeros(n_states)

output ¶

output(input_signal, dt)

Calculate the output of the actuator based on the input signal and time step.

Parameters:

Name	Type	Description	Default
`input_signal`	`float`	Input signal to the actuator.	required
`dt`	`float`	Time step for the simulation.	required

Source code in src/bsm2_python/bsm2/aerationcontrol.py

def output(self, input_signal: float, dt: float):
    """Calculate the output of the actuator based on the input signal and time step.

    Parameters
    ----------
    input_signal : float
        Input signal to the actuator.
    dt : float
        Time step for the simulation.
    """
    dt_arr = np.array([0, dt])
    response = ct.forced_response(self.state_space, U=input_signal, T=dt_arr, X0=self.state)
    self.state = response.states[:, -1]
    y_out = response.outputs[-1]
    return y_out