hydrogym.firedrake.actuator

DampedActuator Objects

class DampedActuator(ActuatorBase)

Simple damped actuator model.

Dynamics are given by the following ODE:

m * dx/dt = k * (u - x)

where x is the state of the actuator, u is the control input, k is the damping coefficient, and m is the inertia. Integrating over a time step dt with a zero- order hold on u gives the following exact solution:

x(t + dt) = u + (x(t) - u) * exp(-k * dt / m)

Since only the ratio k/m enters the dynamics as a time scale tau = m/k, we can think of the dynamics as a low-pass filter with a time constant tau. The single remaining parameter is named damping, and corresponds to k/m = 1/tau.

step

def step(u: float, dt: float)

Update the state of the actuator