New Elevator Speed Control Technology Adopting ILQ Theory

It is important to reduce vertical vibration to establish riding comfort. There are two main difficulties in designing a speed controller. • Rope resonance frequency varies with car position and load. This is especially notable in high rise elevators. • In hydraulic elevators, there is another resonance frequency, due to oil compression. This affects cage speed control performance. Inverse linear quadratic (ILQ) design theory is applied to develop a new speed controller in order to minimize cage vibration. ILQ controllers for both rope and hydraulic elevators are designed. These controllers make it easy to optimize the controller parameters because the control law obtained is represented as a function of plant parameters. A simulator is used to evaluate controller performance. Experimental results confirm its excellent vibration damping performance.