Elevator active suspension system

Year	Description
1990	Invention patented by Randall K. Roberts, Richard L. Hollowell, Clement A. Skalski, and John K. Salmon on July 17th, 1990. Abstract: A method and apparatus for actively counteracting a disturbing force acting on a suspended elevator cab moving vertically in a hoistway is disclosed. A manifestation of the disturbing force such as acceleration is sensed and counteracted, for example, by effectively exerting counterforces against the cab. The magnitude and phase of the counterforce is selected according to the magnitude and phase of the system response to a disturbing force. The invention may be carried out using an electromagnet actuator for actuating the suspended cab in response to a control signal from a control means which is in turn responsive to the sensed signal. The control means may be analog or digital or a combination of both. A preferred analog-digital approach is disclosed in which the digital part is responsive to accelerometer signals, the analog part is responsive to a force command signal from the digital part and provides a force feedback signal for comparison to the force command signal. In a pendulum car embodiment, three pairs of electromagnets form three actuators situated between the floor of the frame and the bottom of the suspended cab.
Source: selected by the editor from original sources.

Invention: Elevator active suspension system