425 Parameter estimation of a standing human-mechanical vibration system based on the frequency response experiment

A system which is representative of most practical galvanometer amplifiers is analysed and the response of the system to alternating e.m.f.'s and to mechanical vibration is determined. It is shown that the values of the circuit constants can be so chosen that the galvanometer movement is at least critically damped for all conditions of operation and that, for critical damping. the frequency response curve for the amplifier to applied alternating e.m.f.'s resembles that for the galvanometer alone but is expanded along the frequency axis by a factor which depends on the degree of feedback. Mechanical vibration with a component about the axis of the galvanometer cod produces an effect which is markedly increased by the provision of feedback.

Download Full-text

Parameter Identification of Weakly Nonlinear Vibration System in Frequency Domain

Shock and Vibration ◽

10.1155/2004/634785 ◽

2004 ◽

Vol 11 (5-6) ◽

pp. 685-692 ◽

Cited By ~ 4

Author(s):

Jiehua Peng ◽

Jiashi Tang ◽

Zili Chen

Keyword(s):

Parameter Identification ◽

Frequency Response ◽

Nonlinear Vibration ◽

Frequency Domain ◽

Response Function ◽

Frequency Response Function ◽

Physical Parameters ◽

Vibration System ◽

Weakly Nonlinear ◽

Nonlinear Vibration System

A new method of identifying parameters of nonlinearly vibrating system in frequency domain is presented in this paper. The problems of parameter identification of the nonlinear dynamic system with nonlinear elastic force or nonlinear damping force are discussed. In the method, the mathematic model of parameter identification is frequency response function. Firstly, by means of perturbation method the frequency response function of weakly nonlinear vibration system is derived. Next, a parameter transformation is made and the frequency response function becomes a linear function of the new parameters. Then, based on this function and with the least square method, physical parameters of the system are identified. Finally, the applicability of the proposed technique is confirmed by numerical simulation.

Download Full-text

On establishing equations of motion of mechanical vibration systems placed on moving bases

International Journal of Mechanical Engineering Education ◽

10.1177/0306419017705522 ◽

2017 ◽

Vol 45 (3) ◽

pp. 209-227

Author(s):

M Gürgöze ◽

F Terzioğlu

Keyword(s):

Degrees Of Freedom ◽

Equations Of Motion ◽

Mechanical Vibration ◽

Main Idea ◽

Vertical Axis ◽

Constant Angular Velocity ◽

Vibration System ◽

Reaction Forces ◽

The Subject ◽

Vibrating Systems

The first author has been teaching the postgraduate course, “The Dynamics of Mechanical Systems” in The ITU Faculty of Mechanical Engineering for nearly 20 years. He has observed that students frequently have problems in obtaining the equations of motion of the vibrating systems which were placed on moving bases. Starting from this observation, he has found that the homework stated below, which was given to the students occasionally, was very helpful in learning the subject. The main idea of the homework is the derivation of the equations of motion, with the help of formulating the Lagrange’s equations with respect to a moving set of axis for a vibration system with two degrees of freedom which consists of a horizontal table rotating with a constant angular velocity around a vertical axis. The students were also asked to solve the same problem with a different method of their choice and to determine the reaction forces as well. We want to share this problem with the reader, which we have assessed as very instructive and appropriate from the viewpoint of applicability of different methods.

Download Full-text