Patent ID: 8761947

Claim:
A system for reducing lateral movement of a car in an elevator system, comprising: a detector configured to sense vibration of the car as a vibration signal; an estimator configured to estimate a state of the elevator system; a controller configured to determine a damping coefficient for a feedback signal according to the vibration signal and the state of the elevator system; and a semi-active actuator arranged between the car and a roller guide assembly, wherein the semi-active actuator includes a rheological fluid, and flow characteristics of the rheological fluid are actuated according to a feedback signal to reduce a lateral movement of the car, wherein the feedback signal is determine according to a control law u = { b ma ⁢ ⁢ x , φ ⁡ ( x ^ , y ) ⁢ v ^ > 0 , b m ⁢ ⁢ i ⁢ ⁢ n , φ ⁡ ( x ^ , y ) ⁢ v ^ ≤ 0 , where u the damping coefficient, b max and b min are maximal and minimal damping coefficients, respectively, {circumflex over (v)} is an estimate of a relative velocity between car and roller guide assembly, {circumflex over (x)} is an estimation of a state of the elevator system, y is the vibration signal, and φ(•) is a function of the vibration signal and the state.