Comfort and good handling are always a problem in conventional passive suspension systems. The ideal suspension criterion is to have a short time response, have a small amplitude and eliminate the frequency of causes of motion sickness. The system is only obtained with an active suspension system. The active suspension has an actuator that is able to produce a force to reduce the dynamic force of the vehicle. This actuator will be controlled by a PID active control. The test results showed that the active control was able to reduce the amplitude by 18 mm, passes the Sickness motion frequency and can return to the set point in 0.8 seconds.

ABSTRAKPotensi energi gelombang laut yang besar dapat dimanfaatkan dengan menerapkan konverter energi gelombang. Salah satu model konverter yang sedang dikembangkan model pendulum vertikal. Pemodelan pendulum vertikal yang sederhana menyebabkan pengaruh massa tidak signifikan terhadap respon gerak pendulum. Demikian juga dengan model dengan penambahan transmisi daya tidak mengakomodir kondisi resonansi. Oleh karena itu, penelitian ini memodelkan dan menganalisis respon gerak pendulum pada konverter energi gelombang dengan inersia tambahan saat resonansi. Amplitudo respon pendulum relatif terhadap arah vertikal gravitasi semakin lama semakin membesar hingga dibatasi nilai amplitudo pergerakan ponton pada kondisi tunak, sedangkan respon relatif terhadap ponton semakin mengecil. Fenomena ini tidak terjadi pada kondisi di luar resonansi.Kata kunci: pendulum vertikal, konverter energi gelombang, inersia tambahan, resonansi PENDAHULUAN Indonesia memiliki potensi energi kelautan yang besar, salah satunya potensi energi gelombang laut. Gerak naik-turun pada arah transversal gelombang ini dapat menggerakkan suatu mekanisme konversi energi tertentu. Mekanisme ini akan mengubah gerak gelombang tersebut menjadi gerak rotasi yang nantinya dapat digunakan untuk memutar generator. Model pendulum yang ditempatkan di atas suatu media terapung dapat menjadi mekanisme tersebut.Salah satu model pendulum yang diteliti adalah pendulum vertikal. Pendulum jenis ini dipilih karena memiliki respon gerakan yang lebih mudah dimodelkan daripada pendulum horizontal [1][2][3][4]. Tinjauan respon pendulum vertikal dalam kondisi mendekati resonansi pernah dilakukan pada model pendulum yang masih sangat sederhana dengan hanya pendulum vertikal yang bergerak relatif terhadap ponton [5]. Model ini memiliki frekuensi natural yang hanya dipengaruhi oleh panjang lengan pendulum. Perlu adanya penelitian lebih lanjut agar parameter sistem pendulum vertikal lain, seperti massa pendulum, dapat turut mempengaruhi frekuensi natural pendulum vertikal.Oleh karena itu, model pendulum vertikal diberi inersia tambahan dalam penelitian ini. Massa pendulum turut mempengaruhi frekuensi natural pada kondisi ini. Semua nilai parameter sistem dan eksitasi ditentukan sedemikian sehingga frekuensi eksitasi sama dengan frekuensi natural sistem. Penelitian ini dapat memberikan respon gerak pendulum domain waktu pada

Statics and frequency analyzes are important because the structure can support the static and dynamic loads. Most previous studies of statics and frequency did not involve the gravity load. The previous studies of gravity effect to the cantilever beam included the hanging, horizontal, and inverted positions. The gravity load direction is applied referred to the longitudinal and lateral beam directions in this study. The closer to the inverted position the smaller the natural frequency. The highest values of the maximum displacement and the maximum Von-Mises stress are happened if longitudinal position is horizontal and lateral orientation angle is 0°. The change of lateral orientation angle does not influence the natural frequency in this condition. Keywords—Cantilever beam, gravity load, natural frequency, orientation angle, statics

In this global era there are many resources that can be used one of them is, renewable resources such as sea waves. waves can be used as a generated of electrical energy. electrical energy that utilizes the occurrence of sea waves now can be applied in developed and developing countries. One method of conversion that can be done to convert wave energy into electrical energy is by using an oscillating water column. In this research, the turbine of oscillating water column was made using turbine wells with variations in rotation at 40, 50 and 58.3 rpm. the results it’s power of turbine, power of generator and efficiency system. The method used is the experimental method by testing the prototype using a low water wave on a laboratory scale. The results obtained from the experiment are that the electric power at the maximum load generated by the generator is 0.002875 Watt at a rotation of 50 rpm. While the lowest electric power at maximum load is 0.0004 W with a rotation of 40 rpm. The maximum efficiency of the system at load is 4.691% which occurs at a rotation of 50 rpm

Low-frequency vibration has been troublesome for a mechanical system. Despite the measurement difficulties, low-frequency vibration also creates several environmental effects such as high noise level that is harmful to the human body. One of the methods to reduce vibration is tuning the vibration isolation i.e. spring and damping coefficient. However, the latter method is found to be effective only for the mid-high frequency range. Therefore, this paper proposes an optimization of the spring a.k.a. stiffness coefficient in order to reduce the low-frequency vibration. The Taguchi method is used as an optimization tool since it offers simplicity yet powerful for any field of application, particularly in engineering. Two significant parameters in the spring geometry were selected as the optimization variable in the Taguchi method and evaluated using vibration transmissibility concept. The result shows that the Taguchi method has been successfully obtained the optimum value for the spring geometry purposely to reduce the vibration transmissibility.