Sway Reduction on Container Cranes Using Delayed Feedback Controller

2003 ◽  
Vol 34 (3/4) ◽  
pp. 347-358 ◽  
Author(s):  
Ziyad N. Masoud ◽  
Ali H. Nayfeh
2005 ◽  
Vol 11 (8) ◽  
pp. 1103-1122 ◽  
Author(s):  
Ziyad N. Masoud ◽  
Ali H. Nayfeh ◽  
Nader A. Nayfeh

Traditionally, a container crane is modeled as a simple pendulum with either a flexible or a rigid hoisting cable, and a lumped mass at the end of the cable. However, in the case of quay-side container cranes, the actual configuration of the hoisting mechanism is significantly different; it consists typically of a set of four hoisting cables. The cables are hoisted from four different points on a trolley and are attached on the load side to four points on a spreader bar used to lift containers. A controller design based on the actual model will most likely result in a response superior to those based on simple pendulum models. In this paper, we develop a mathematical model of the actual quay-side container crane. A simplified model is then used to obtain the gain and time delay for a delayed feedback controller, which will be used for the control of payload sway oscillation. Performance of the controller is simulated on a 1/10th scale computer model of a 65 ton container crane using the full model. Simulation results are verified experimentally on a 1/10th scale model of the same container crane.


Author(s):  
Fadi Alsaleem ◽  
Mohammad I. Younis

In this work, we investigate the stability and integrity of parallel-plate microelectromechanical systems resonators using a delayed feedback controller. Two case studies are investigated: a capacitive sensor made of cantilever beams with a proof mass at their tip and a clamped-clamped microbeam. Dover-cliff integrity curves and basin-of-attraction analysis are used for the stability assessment of the frequency response of the resonators for several scenarios of positive and negative gain in the controller. It is found that in the case of a positive gain, a velocity or a displacement feedback controller can be used to effectively enhance the stability of the resonators. This is confirmed by an increase in the area of the basin of attraction of the resonator and in shifting the Dover-cliff curve to higher values. On the other hand, it is shown that a negative gain can significantly weaken the stability and integrity of the resonators. This can be of useful use in MEMS for actuation applications, such as in the case of capacitive switches, to lower the activation voltage of these devices and to ensure their trigger under all initial conditions.


Informatica ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 233-249 ◽  
Author(s):  
Raimondas Čiegis ◽  
Olga Suboč ◽  
Remigijus Čiegis

Author(s):  
Karim M. Masri ◽  
Mohammad I. Younis ◽  
Shuai Shao

Controlling mechanical systems is an important branch of mechanical engineering. Several techniques have been used to control Microelectromechanical systems (MEMS) resonators. In this paper, we study the effect of a delayed feedback controller on stabilizing MEMS resonators. A delayed feedback velocity controller is implemented through modifying the parallel plate electrostatic force used to excite the resonator into motion. A nonlinear single degree of freedom model is used to simulate the resonator response. Long time integration is used first. Then, a finite deference technique to capture periodic motion combined with the Floquet theory is used to capture the stable and unstable periodic responses. We show that applying a suitable positive gain can stabilize the MEMS resonator near or inside the instability dynamic pull in band. We also study the stability of the resonator by tracking its basins of attraction while sweeping the controller gain and the frequency of excitations. For positive delayed gains, we notice significant enhancement in the safe area of the basins of attraction.


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