Actively Compensate for Vibrations

At Hannover Messe (April 20-24, 2009), ContiTech Vibration Control presents an active antivibration system that can apply countervibration to specifically and flexibly neutralize the resonant vibration of a drive or system. "Active antivibration systems are appropriate wherever structureborne sound interferes with the operation of systems, machines and vehicles," explained Dr. Hans-Jürgen Karkosch, head of Advanced Development at ContiTech Vibration Control. The productionready system is currently in the test phase in several industrial sectors such as the automotive industry. In hall 25 at booth E23, a simulation model exhibits the technical and physical principles behind active antivibration technology. ContiTech Vibration Control also provides information on the anti-vibration technology applications for mechanical and systems engineering in its SCHWINGMETALL® and MEGI® product lines.

An active antivibration system consists of four components: an actuator to generate forces, an electronic control unit, a power amplifier and an acceleration sensor. The company holds a key patent for an electromagnetic actuator. Actuator design and the functional development of the active systems are core areas of expertise at ContiTech Vibration Control. And when it comes to control unit and sensor development, the expertise of the entire Continental Corporation is a ready resource.

A sensor measures the vibrations transmitted to the components of an assembly, machine or system and the information is sent to an electronic control unit. Together with an amplifier, the unit modifies the sensor signal to make the actuator generate a vibration with the same amplitude but dephased by 180 degrees. This can offset undesirable excitation. Audible frequencies become quieter and vibrations are substantially reduced. To ensure an adequate offset, the countervibration of the actuator in the overall operating range (20 - 800 Hz) has to be generated with an accuracy of

± 5 degrees in the phase and ± 0.5 dB in the amplitude. The electronic control unit for implementing specially-developed control algorithms is at the core of the active anti-vibration system. An autotuning function is responsible for the system's fine adjustment. Depending on the application, a control unit can address one or more actuators at the same time.