MATHEMATICAL MODELING AND VIBRATIONAL ANALYSIS OF HELICOPTER SLING-LOAD MECHANISM

Abstract

Of the best machines that are employed worldwide for
transporting or carrying heavy load over large
distances, helicopter is the one. If we talk about the
mechanism(s) used for the very job, there are the
suspended cables below the helicopter. In response,
disturbance forces such as wind coupled, with the
helicopter motion the suspended load oscillates. The
oscillations load carried by the suspended cables
below the helicopter is not only dangerous but also
affects the control of helicopter, and that too adversely.
In the aerospace community the application of
helicopter carrying external suspended loads is of
significant focus owing to the stability problems in
such systems. In the past, most of the work was
focused on determining the favorable wire length,
helicopter load ratios for stability analysis. In addition,
the design of techniques that could augment stability
in the slung load systems had also been the focus of
past researches. In addition, a few of the researches
focused on situation specific and simple models;
however, most work in the past was focused on more
general models that were suitable for control and
simulation. The literature review, along with generic
approaches to modeling slung load, discusses input
shaping method to helicopter’s flight controller in
order to gain stability. So far as this paper is concerned,
it includes mathematical modeling of the sling load in
single degree of freedom. Additionally, in this paper
we discusses different conditions to model sling load
such as: un-damped free vibrations, damped free
vibrations, vibration under harmonic forces and
vibration under general forcing conditions. The
finding of our paper presents the response of the sling
load modeled in single degree of freedom under
certain conditions. In this article we will learn as to
how helicopter sling-load can be modeled and
mathematically in single degree of freedom, and what
is the response of the sling load under different
conditions.