Semi-Active Vibration Control of High-Speed Elevators Using MR Dampers and Shape Memory Alloys

Purpose This article numerically investigates the acceleration response of a two-degree-of-freedom vertical transportation model excited by deformations in the rail guide, proposing three stages of vibration control. First, an active control using the State-Dependent Riccati Equation (SDRE) is proposed; subsequently, a semi-active control strategy, considering two distinct strategies for magnetorheological dampers and shape-memory-alloy springs, is evaluated. Methods and Results To analyze the levels of lateral and angular acceleration, as well as the efficiency of magnetorheological dampers or shape-memory-alloy springs, numerical analyses are performed using RMS (Root Mean Square) accelerations. The forces of the magnetorheological damper and the shape-memory-alloy springs are controlled using State-Dependent Riccati Equation (SDRE) control. This involves controlling the applied electrical voltage to the magnetorheological damper coil and the temperature of the shape-memory-alloy spring. Additionally, the effects of elevator travel speed and suspended mass on system performance are investigated. The robustness of the controller to random variations in cabin mass and to noise in the input and output signals is also evaluated. To mitigate the effects of this noise and improve system performance under uncertainty, LQG control is adopted, integrating an LQR regulator with a Kalman filter for state estimation. Conclusions The numerical simulations demonstrated that the control strategies significantly reduced the acceleration levels in the elevator cabin. The proposed control of the electrical voltage applied to the magnetorheological damper coil using the control signal proved efficient and adequate for controlling the damper's shape. It also proved efficient and adequate for controlling the temperature of the molding alloy by using the control signal to determine the force applied to the springs.