Active control of acoustic noise

One of the problems in which the SAC group has been working recently is in the active control of acoustic noise, applied to tubes, cameras and helmets of motorcycles. The objective is to implement strategies of active control that allow to reduce the environmental noise. To attain this objective, we have been working with feedback and feedforward co controllers refeeded (feedback) and anticipatory (feedforward) and combinations of both (hybrid strategies).

During these last years, it has received an special attention the case of the helmet in motorcycles, due to the recent European legislation on environmental noise at work. This legislation establishes the maximum level of acoustic noise that a worker can bear, and attempts to avoid the loss of induced audition (NIHL). The problem falls on the fact that the existing technology can not fulfill the regulation. Different medical studies point that this will specially affect to professionals drivers (policeman, distributors, sportsmen, instructors). There are few works of CAR in helmet, but the hybrid structure of control seems quite promising. It is still missing to solve problems of stability of the adaptative anticipatory controllers, alternatives of non linear controllers and / or modifications in the time, and implementation and manipulation of real-time data.