Computer simulation model of a lift car assembly with an active tuned mass damper

In engineering systems a Passive Tuned Mass Damper (a secondary mass – spring - damper combination) is often used to reduce vibrations of a primary structure (main mass). In an Active Tuned Mass Damper (ATMD) arrangement vibrations of the main mass are attenuated when the secondary mass (referred to as an active mass) is actively controlled. The ATMD system is equipped with a controller, sensors and an actuator. The attenuation is achieved by the application of control force determined by a suitable feedback control algorithm. In this paper the ATMD method is considered to attenuate resonance vertical vibrations of a lift car assembly – suspension rope system during the lift travel, when the frequency of harmonic excitation acting upon the car assembly becomes near its natural frequency. A mathematical model with the optimal feedback gain calculated using Linear–Quadratic Regulator control law is developed. Then, a case study is presented in which computer simulation is carried out. The simulation results are discussed and the effectiveness of an active tuned mass damper system is demonstrated for a given set of lift system parameters.