Judul: Implementasi Inverse Kinematics untuk Koordinasi Gerak Robot Berkaki Enam
Abstrak: Six legged robot, or hexapod, is a kind of legged robots with static stability. The robot has many variants of leg movements. This should be taken into consideration by the robot designer. The research is to adopt a leg movement algorithm named inverse kinematics. Inverse kinematics is used to find each leg angle required to produce certain position of the end-effector. The experiments show that pulse width input can move the robot faster than that with end-effector displacement distance input. However, the distance input is more flexible due to its simplicity such that the user can input the desired end-effector displacement distance without relying on the pre-determined distances. The inverse kinematics algorithm has been developed, although it is not able to avoid or circumvent the barriers.
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Judul: Analisys gerakan robot berkaki enam menggunakan 3 Servo dan Sensor Jarak
Abstrak: Pada umumnya, hexapod menggunakan 18 servo. Namun, penggunaan servo yang terlalu banyak mengakibatkan konsumsi daya yang terlalu besar, biaya yang mahal, algoritme pergerakan kaki yang kompleks, dan pergerakan kaki yang lambat. Penelitian ini bertujuan mengembangkan hexapod dengan 3 servo, yang diletakkan di bagian tengah dan belakang robot. Peletakan servo di bagian tengah digunakan untuk mengangkat kaki depan dan belakang pada sisi yang sama, sedangkan peletakan dua buah servo pada bagian belakang robot digunakan untuk menggerakkan kaki depan dan belakang yang sudah saling terhubung. Algoritme pergerakan kaki yang digunakan adalah algoritme Alternating Tripod Gait yang membagi gerakan kaki menjadi 2 set gerakan seperti tripod. Tiap set gerakan terdiri atas 3 kaki, yaitu kaki depan dan belakang pada sisi yang sama, serta kaki tengah pada sisi yang berbeda. Masing-masing set bergerak secara bergantian. Hasil penelitian ini menunjukkan bahwa 3 servo dapat diimplementasikan pada robot hexapod dengan menggunakan algoritme pergerakan Alternating Tripod Gait. Hasil eksperimen menunjukkan bahwa hexapod dengan 3 servo yang telah dibuat dapat berjalan dengan kecepatan 0.047 m/s, lebih cepat 0.017 m/s daripada hexapod dengan 18 servo. Selain itu, bobot hexapod dengan 3 servo adalah 210 gram, jauh lebih ringan dibandingkan dengan hexapod 18 servo yang berbobot lebih dari 3 kg.
Keyword: alternating tripod gait, hexapod, robot, servo

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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