A variable-structure control method for the suppression of elevator-cage vibration

A new control method (i.e., a controller) controller with a variable structure that consists of multiple linear controllers-for suppressing the vertical vibration of a fast elevator has been developed. Each linear controller is designed by using a Hinfinity control method to suppress the vertical vibration of the cage. Moreover, the linear controllers are switched according to the position of the elevator. It has been found that the developed controller reduces the amplitude of the cage's vibration to one-half that of our previous design.