A radio frequency (RF) power generation system includes a RF power source that generates a RF output signal delivered to a load. A RF power controller is configured to generate a control signal to vary the RF output signal. The controller adjusts a parameter associated with the RF output signal, and the parameter is controlled in accordance with a trigger signal. The parameter is adjusted in accordance with a cost function, and the cost function is determined by intruding a perturbation into an actuator that affects the cost function. The actuator may control an external RF output signal, and the trigger signal may vary in accordance with the external RF output signal.