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| Articles
by
Setyamartana Parman |
Total Records (
5 ) for
Setyamartana Parman |
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Affiani Machmudah
and
Setyamartana Parman
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This study addresses a point-to-point of an arm robot motion planning in complex
geometrical obstacle considering all kinematics and dynamics constraints. A
continuous function of a seventh degree polynomial is utilized as a joint angle
path. The path planning optimization objective is to minimize a joint angle
traveling distance under avoiding collision constraint. After the best path
has been discovered, the trajectories will be optimized with an objective is
to minimize the total traveling time and the torque under the maximum velocity,
the maximum acceleration, the maximum jerk and the maximum torque constraints.
Three Degree of Freedom (3-DOF) planar robot will be utilized to simulate the
proposed method. The computational strategy utilizing a Genetic Algorithm (GA)
will be presented. There is no information regarding the region of the feasible
seventh degree polynomial joint angle path so that the GA should search it first.
At the first computation where the population is generated randomly, all individuals
commonly collide with obstacles. It needs a requirement to escape from zero
fitness. After the feasible individual has been discovered, the GA should evolve
this individual to find the best one with the highest fitness value. Results
show that the feasible joint angle path which is very smooth in the motion has
succeeded to be found. The trajectories are also discovered successfully without
exceeding the constraint values. |
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Edwar Yazid
,
Setyamartana Parman
and
Khairul Fuad
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In this paper, dynamic behavior of non-slewing-luffing crane type, namely gantry crane is investigated by introducing the flexibility of crane framework and hoist cable. The dynamic model of such system is obtained by modeling crane framework using finite element method and gantry crane system by using Lagranges equations. The equations of motion constitute nonlinear coupling terms between crane framework and crane system. The coupled dynamic equations are solved numerically using a combinational direct integration technique, namely Newmark-β and fourth-order Runge-Kutta method. Numerical simulations are carried out to obtain the open-loop responses as functions of limited set parameters for quite simple but representative for gantry crane system. |
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Bambang Ariwahjoedi
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Setyamartana Parman
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By taking the analogy with bio-molecular systems, many systems containing simple molecular entities like water could have an information storage system. This storage system is similar to a gene locus which is presumably enclosed within the nucleus of its atoms. Information are stored in the form of perhaps such kind of fundamental interactions among sub-sub-atomic particles within each nucleons, just like hydrogen bonding among the nucleotides residue in the DNA. If this is true, then small molecules, water molecules for example, might be no longer as all-identical entities, instead they might all be organisms, which each of them is individually unique in their own. Furthermore, if this could someday be comprehended, many natural phenomena which are still not well understood due to their complexity such as cloud morphology in the sky, crystallization pattern of snow flakes and crack pattern in drying clay mud, etc., could be rationalized in a fundamental way, still by using physicochemical if not nucleo-chemical principles. |
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Edwar Yazid
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Mohd. Shahir Liew
and
Setyamartana Parman
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The purpose of this study is to propose and investigate a
new approach for extracting spectral information of motion response of offshore
structures. The approach is based on applying Time-varying Autoregressive (TVAR)
model. This study is virtually unexplored in offshore engineering field. In
the literatures, a number of works have shown that spectral content are extracted
using Discrete Fourier Transform (DFT) for the frequency-domain analysis. Here,
we outline a practical algorithm for TVAR model which uses Expectation-maximization
(EM) algorithm based Kalman smoother. Short time Fourier transformation and
Hilbert transformation are used as benchmark. The method is then applied to
sampled discrete displacements of a fixed platform as a time series generated
from field measurements. All the methods reveal that the spectrum characteristics
of sampled platform displacement are time- varying frequency and time- varying
gain distribution. The results indicate that TVAR model using KS with EM algorithm
is superior to other methods in tackling frequency or amplitude modulation and
systems that have low frequency dynamics. It is also found out that the mean
frequency derived from the Hilbert transform is lower 8.2%, around 4.8% for
short time Fourier transformation and 6.2% for TVAR model than the FFT spectrum. |
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Setyamartana Parman
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Bambang Ari-Wahjoedi
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Edward Halawa
and
Affiani Machmudah
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Attitude maneuvers of a Communication Technology Satellite
(CTS)-like spacecraft using constant-amplitude thrusters is of great importance.
The spacecraft consists of a rigid main body and two symmetrical solar panels.
When the panels are large, they cannot be treated as rigid bodies anymore. They
are supposed to behave structural flexibility. To discrete their motion, the
finite element method is followed. Under constant-amplitude thrusts, steady-state
attitude angle oscillations may occur in large amplitude after the maneuvers.
Since, the spacecraft should point to the earth precisely, these oscillations
must be reduced into small permissible values. To reduce residual attitude angle
oscillations, Proportional Derivative (PD) based constant-amplitude input shaping
logic is proposed to determine time locations of thruster switching. Then, under
such inputs, attitude maneuvers of the spacecraft are simulated numerically.
Results of simulations show that the precise orientation of the satellite can
be achieved. |
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