Observer-based controller for floor vibration control with optimization algorithms

Abstract

This study presents the results of vibration suppression of a walkway bridge structure with a single actuator and sensor pair by using a proportional-integral (PI) controller and observer-based poleplacement controllers. From the results of experimental modal analysis (EMA), reduced order models of the walkway are identified. These are used for the design of a PI controller as well as for state estimation procedures that are necessary for development of reduced-order observer controllers. The respective orders of the latter are dependent on the number of plant modes used for their designs. They are formulated from plant and observer feedback gains that are obtained from specification of desired floor closed-loop eigenvalues and observer eigenvalues. There are numerous solutions possible with the observer-based controller design procedures whereas the PI controller defaults to a particular solution. There is also the flexibility for isolation and control of target vibration modes with the observer-based controllers for higher controller orders from a purely single-input single-output controller scheme as demonstrated in the analytical and experimental studies presented. Further, in this work, a design space of potential feedback gains is specified, where only a single plant mode has been used for the observer-based controller design process, and a multi-objective genetic algorithm optimisation scheme is used to search for an optimal solution within some pre-defined constraint conditions. The best solution here is regarded as one that offers the greatest vibration mitigation performance amongst the solutions identified.

Preventing stroke saturation of inertial actuators used for active vibration control of floor structures

“…In order to provide a phase distortion between actuator and structure such that the AVC system efficacy is not affected, the actuator natural frequency is desired to be sufficiently below fundamental natural frequency of the structure with a recommended value of less than half of . To satisfy this recommendation, the optimal natural frequency and other characteristics of actuator dynamics are summarized in Table .…”

Comparative studies of global and targeted control of walkway bridge resonant frequencies

“…Following the procedure outlined by Nyawako and Reynolds (2015), the feedback signal, Kpx^(t), is driven by u(t) and y(t) in equations (2) and (3), respectively. These are then expressed as the two subsystems Hu(s) and Hy(s) in equations (4) and (5) in the Laplace domain.…”

“…Their force-voltage (N/V) and displacement-voltage (m/V) characteristics are shown in Equations 14 and 15 (Nyawako et al 2015 = 300 and _ = 10 are constant parameters. > 1 is the design gain constant of the notch filter for each of the controllers.…”

“…Following the procedure outlined in Nyawako et al (2015), the feedback signal, ̂( ), is driven by ( ) and ( ) in Equations 2 and 3 in which ̂1( ) and ̂2( ) are only used to distinguish modal states driven by ( ) and ( ).…”

Incorporating a disturbance observer with direct velocity feedback for control of human-induced vibrations

“…This is shown in Figure 2a and Figure 2b shows a plan view of the test points that were used for experimental modal analysis (EMA) tests. Further details of these tests are given in 13 . A summary of the estimated modal properties of the lowest four vibration modes observable at Test Point (TP) 7 are presented in Table 1.…”