The more the development of super high-rise buildings, the faster the speed of elevator in order to shorten the riding time of elevator and the waiting time of passengers. With the increase of elevator speed, the horizontal vibration of passenger car becomes more significant resulting in the decrease of serviceability and safety of elevator, and the discomfort of passengers. The horizontal vibration is mainly generated from the elevator wheels running on rough and winding guide rails. In this paper, a four degree-of-freedom (DOF) elevator system was established to examine the characteristics of the excitations and to analyze the dynamic responses of the elevator. An active mass driver (AMD) was developed to reduce the horizontal acceleration of passenger car in the elevator based on H∞ direct output feedback control algorithm. The optimal control force is obtained from the multiplication of direct output measurements by a pre-calculated time-invariant gain matrix. To achieve optimal control performance, the strategy to select both control parameters γ and α was investigated extensively. Numerical verification results show that decrease in γ or increase in α yields better control performance with an acceptable magnitude of control force. The selective ranges of γ and α making a controlled system become overdamped or unstable were found. To assure system stability and control efficiency, the upper bound of α were derived and illustrated graphically. An optimum design flowchart was also proposed. Finally, a full-scaled high-speed elevator system was investigated to prove the applicability and control effectiveness of the proposed AMD system.
Bilateral Output Feedback Control of Fractional PDEs with Space-Dependent Coefficients