A Proposal of Control Method for an Elevator Emergency Stop Device With a Magnetic Rheological Fluid Damper

When an elevator emergency stop device is in operation, large deceleration is generated in the elevator cage. Passengers in the elevator cage sometimes get injured, because the deceleration by the elevator emergency stop device is outrageous. Therefore, the authors focused on the passengers' safety in elevators and proposed an emergency stop device with a spring and a magnetic rheological fluid (MRF) damper, which makes it possible to continuously vary its damping coefficient by controlling the magnetic field. To control the magnetic field, current of a coil surrounding the damper must be regulated. Since this type of emergency stop device is a nonlinear system, a suitable control input must be theoretically formulated. In this paper, a nonlinear controller suitable for MRF damper was designed and its control effectiveness in elevators was confirmed by digital simulations.