International Research Journal of Engineering and Technology (IRJET) Volume: 04 Issue: 03 | Mar -2017
www.irjet.net
e-ISSN: 2395 -0056 p-ISSN: 2395-0072
Control Algorithms for Evaluating Seismic Performance of Structures Aparna M K1, Shashidharan 2 1MTech
Scholar, Department of Civil Engineering, NSS College of Engineering, Palakkad, Kerala, India Department of Civil Engineering, NSS College of Engineering, Palakkad, Kerala, India
2Professer,
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Abstract - Passive control refers to systems that do not
require an external power source. To enhance the performance of passive control systems, active control systems are developed. In active control system, sensors measure the motions of the structure and actuators and a feedback control strategy exert counteracting forces to compensate for the effect of external excitations. In this paper three different control algorithms namely LQR control algorithm, a filtered xLMS algorithm and a hybrid feedback LMS control algorithm are studied and their performance in seismic control of structures are also reviewed. LQR is a feedback control algorithm and filtered-x LMS is an adaptive control whereas the hybrid feedback LMS is a combination of feedback and adaptive control algorithms. A brief idea about ATMD and different types of control algorithms are briefly explained.. Key Words: Active Tuned Mass Damper, Active Control Algorithm, LQR feedback control, LMS control, filtered-x LMS control.
Fig -1: Active Control System
2. ACTIVE TUNED MASS DAMPER
1. INTRODUCTION
Active Tuned Mass Damper (ATMD) is evolved from Tuned Mass Damper (TMD) with the addition of an active control mechanism. TMDs are only effective for structural response control when the first mode is dominant. Development of AMDs focuses on seeking control of structural seismic response with a wide frequency band. For ATMD one actuator is installed between the primary (i.e., structure) and the auxiliary (i.e., TMD) systems. The actuator controls the motion of the auxiliary system to increase the control effectiveness. Many analytical studies have been done to find how to operate the actuator to subdue response of the primary system most effectively with optimum control law and to find the appropriate feedback gain of the ATMD in order to obtain optimum control input. ATMDs have an economic advantage in full-scale structures because far less control force and a much smaller actuator are required than for other active systems.
An active control system can be defined as a system that requires a large power source for the operation of electrohydraulic or electromechanical actuator. These actuators increase the stiffness or damping of the structure. The active control system uses sensors for measuring the ground excitation and structural responses, and actuators for controlling the unwanted vibrations. The working principle of the active control system is that, based on the measured structural response the control algorithm will generate control signal required to attenuate the vibration. With the help of this control signal, the actuators placed at different locations of the structure generate a secondary vibrational response which in turn reduces the overall structural response. The power requirements of these actuators vary from kilowatts to several megawatts with respect to the size of the structure. There are many active control devices designed for structural control applications. Some of them are active tuned mass damper (ATMD), active tendons, active brace systems, pulse generation systems, etc. Some of the control algorithms are feedback control, adaptive control and hybrid control.
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