Wiwiek Hendrowati

THE EFFECT of USING CURRENT STABILIZER to the DYNAMIC CHARACTERISTIC of a REGENERATIVE SHOCK ABSORBER

Most of the energy from the vehicle is wasted in the form of heat energy and vibration. On vehicles, the largest vibration occurs in the suspension system. The development of a mechanism which can recover the vibration energy and convert it into electrical energy, named Regenerative Shock Absorber (RSA), will be detailed in this paper. The prototype of RSA which consist of gear transmission and an electromagnetic type electric generator was studied and analyzed. Electrical circuit signal conditioner / stabilizer is added into the RSA system to stabilize the output current of the generator so that the generated electrical energy can be stored in the battery of 6 volts. The characteristics of the RSA are obtained by testing the value of the damping coefficient, the energy absorbtion capacity, and the generated electrical energy before and after going through a series of signal conditioner. Experiment was also performed by measuring the acceleration response time of the sprung and un-sprung suspension system that uses RSA with damping ratio value of 0.6. From this research, it is found that RSA design with stabilizer circuit can produce more stable electric current and voltage. The measurement results show the value of the electrical voltage output through the generator is fluctuating with an average value of 15 volts and a constant 6 volts output is obtained through the signal conditioning circuit. Furthermore, the dynamic response is obtained in the form of acceleration time-value of less than 0.2 m/s2 in a corresponding ISO 2631 standard is stated very comfortable.

Modeling and Analysis of Hybrid Shock Absorber for Military Vehicle Suspension

This paper deals with the design, modeling and analysis of a hybrid shock absorber for vehicle suspension. A specific design of frictional-electromagnetic-regenerative shock absorber is proposed. The hybrid shock absorber consists of the proposed frictional-electromagnetic-regenerative shock absorber assembled in parallel with a conventional-viscous shock absorber. The concept of hybrid shock absorber is proposed due to the following advantages: the regenerative shock absorber will recover some wasted vibration energy from the suspension into electrical energy to support the need for electrical energy of the vehicle, while the viscous shock absorber maintains the performance of suspension closed to its original suspension. The vehicle suspension system dynamic was mathematically modeled for three different types of suspension:1).Conventional suspension using viscous shock absorber; 2).Hybrid suspension using combination of 50% frictional-electromagnetic-regenerative shock absorberand50% viscous shock absorber; and 3).Full regenerative suspension using 100% frictional-electromagnetic-regenerative shock absorber. In this research, 6 wheels military vehicle (APC:Armour Personal Carrier) is chosen as the model due to the high possibility of applying regenerative suspension to the military/off road vehicle. Based on the mathematical models, performances of the vehicle suspension and the regenerated power from regenerative shock absorber (RSA) were simulated. The results were compared between the three types of suspension and discussed.

Modelling and analysis of a half car (front-rear) energy regenerating suspension with hydro-magneto-electric shock absorber

Shock absorber is designed to convert the kinetic energy from impact into heat energy that is dissipated. The dissipated energy that is produced by conventional shock absorber is wasted. The aim of this paper is to design the shock absorber that can damp the impact and can harvest energy at the same time. It is called Hydro-Magneto-Electric Regenerative Shock Absorber (HMERSA). This research simulated the HMERSA that applied on a front and rear suspension system of a car. The car speed was varied from 0 km/h to 80 km/h. The phase difference of front and rear suspension’s input were 0° and 90°. The results show that the highest power generated is 165 Watt at car speed of 80 km/h and occurred when the phase difference was 0°.Shock absorber is designed to convert the kinetic energy from impact into heat energy that is dissipated. The dissipated energy that is produced by conventional shock absorber is wasted. The aim of this paper is to design the shock absorber that can damp the impact and can harvest energy at the same time. It is called Hydro-Magneto-Electric Regenerative Shock Absorber (HMERSA). This research simulated the HMERSA that applied on a front and rear suspension system of a car. The car speed was varied from 0 km/h to 80 km/h. The phase difference of front and rear suspension’s input were 0° and 90°. The results show that the highest power generated is 165 Watt at car speed of 80 km/h and occurred when the phase difference was 0°.

Optimizing the value of reduction and generating energy on mechanism of cantilever piezoelectric vibration absorber (CPVA)

CPVA (Cantilever Piezoelectric Vibration Absorber) is a mechanism that can reduce vibration and produce electricity. Its working principle combines DVA (Dynamic Vibration Absorber) and Energy Harvesting with Piezoelectric cantilever method. By pairing the CPVA mechanism on the main system, the vibration energy in the main system will be damped then it can be converted into electrical energy. The amount of reduction and electrical energy generated by CPVA mechanism can be optimized by regulating the use of Cantilever Piezoelectric on CPVA mechanism. This study stated that the optimum CPVA mechanism is CPVA which uses the number of Piezoelectric cantilever as 1400-2400 pieces and it is operated at natural frequency 20.61 rad / s with amplitude 0.3 m and 0.35 m. The resulting of vibration reduction is 20.28% up to 22.75%. And the electrical energy generated is 2.17E-7 to 5.78E-7 watts.CPVA (Cantilever Piezoelectric Vibration Absorber) is a mechanism that can reduce vibration and produce electricity. Its working principle combines DVA (Dynamic Vibration Absorber) and Energy Harvesting with Piezoelectric cantilever method. By pairing the CPVA mechanism on the main system, the vibration energy in the main system will be damped then it can be converted into electrical energy. The amount of reduction and electrical energy generated by CPVA mechanism can be optimized by regulating the use of Cantilever Piezoelectric on CPVA mechanism. This study stated that the optimum CPVA mechanism is CPVA which uses the number of Piezoelectric cantilever as 1400-2400 pieces and it is operated at natural frequency 20.61 rad / s with amplitude 0.3 m and 0.35 m. The resulting of vibration reduction is 20.28% up to 22.75%. And the electrical energy generated is 2.17E-7 to 5.78E-7 watts.

Pemodelan dan Analisa Reduksi Respon Getaran Translasi pada Sistem Utama dan Energi Listrik yang Dihasilkan oleh Mekanisme Dynamic Vibration Absorber Metode Cantilever Piezoelectric (CPVA)

Getaran banyak terjadi pada mesin-mesin di industri. Salah satu solusi untuk mereduksi getaran berlebih adalah dengan menambahkan Dynamic Vibration Absorber (DVA). Prinsip kerja dari Dynamic Vibration Absorber adalah penambahan massa absorber dan pegas pada sistem utama. DVA akan mereduksi getaran sistem utama dengan menghasilkan getaran yang arahnya berlawanan dengan arah getar dari sistem utama. Berdasarkan penelitian yang dilakukan oleh Pachpute [1], penggunaan DVA telah terbukti dapat mereduksi getaran dari sistem utama yang dioperasikan di frekuensi natural secara signifikan. Dalam penelitian Tugas Akhir ini telah dirancang sebuah mekanisme alat vibration absorber dan energy harvesting metode Cantilever Piezoelectric Vibration Absorber (CPVA). Sistem utama yang digunakan dalam penelitian ini adalah plat datar yang ditopang oleh empat pegas. Plat tersebut akan menerima gaya eksitasi dari pegas dibawahnya yang dihubungkan dengan massa eksentris pada motor DC. Koefisien pegas yang digunakan untuk menumpu plat datar memiliki nilai yang sama, yaitu sebesar 300 N/m. Sehingga eksitasi yang terjadi pada plat datar hanya ke arah translasi. Pada penelitian ini, dilakukan analisa dengan variasi amplitudo massa eksentris sebesar 0.025 m, 0.030 m, dan 0.035 m. Kecepatan putaran motor sebesar 20.61 rad/s (frekuensi natural), 22.05 rad/s (frekuensi panen), dan 25 rad/s (frekuensi lembah). Sedangkan variasi jumlah cantilever piezoelectric yang digunakan adalah 2600, 2800, dan 3000 buah. Dari simulasi yang telah dilakukan, daya bangkitan dan nilai persentase reduksi terbesar dari CPVA terjadi ketika sistem dioperasikan di frekuensi naturalnya, yaitu sebesar 3.52E-7 watt dan 20.36%. Selain itu, dari simulasi juga didapatkan karakteristik CPVA dengan memvariasikan jumlah piezoelectric, didapatkan rentang jumlah piezoelectric optimum adalah 1400 hingga 2400 buah. Pada rentang tersebut, daya bangkitan dan persentase reduksi perpindahan massa utama terbesar yang dapat dicapai CPVA sebesar 5.78E-7 watt dan 22.75%.

Experimental Study on the Dynamic Characteristics of Hydro-Magneto-Electric-Regenerative Shock Absorber

Regenerative shock absorber is designed to convert the vibration energy losses from the vehicle suspension into electricity. This paper presents an experimental study on the dynamic characteristics of hydro-magneto-electric-regenerative shock absorber (HMERSA). Study was carried out by developing a prototype of HMERSA and testing its dynamic characteristics. The results were analyzed and discussed. Prototype of the HMERSA consists of hydraulic system and electric generator. The HMERSA was tested using a quarter car suspension test rig with input displacement in various frequency (1.3Hz, 1.5Hz, 1.7Hz) and for HMERSA’s various oil viscousity (ISO VG 10, 32, 46). Sprung mass acceleration and the generated electric power representing the dynamic characteristics of HMERSA were measured. Maximum power 2.5 watt and root mean square acceleration 0.172 m/s2 gained for HMERSA with oil viscousity ISO VG 10 at all excitation frequency.

EXPERIMENTAL STUDY and ANALYSIS of the GENERATED ELECTRIC POWER of SALTER DUCK-OCEAN WAVE ENERGY HARVESTER (OWEH) DUE to ADDITIONAL WEIGHT CHANGE and WAVE AMPLITUDE

Among ocean energy, wave energy is one of the energy which has not been utilized optimally. As Indonesia has the longest coastline in the world, the development of OWEH is very important. In this paper, an experimental study and analysis of the generated electric power of Salter Duck type OWEH due to additional weight change and wave amplitude was carried out. Salter Duck is geometrically similar to the duck beak invented by Stephen Salter. The incoming wave toward the nodding duck area will move the beak up and down. This up-down motion is used to rotate the gear transmission system and electric generator. In this research, various additional weight was mounted on the Salter Duck beak and its influence to the generated power was studied at various wave amplitude.The experimental results show that additional weight of 300gr and wave amplitude of 0.028m to the model of OWEH can produce maximum electric power of 19.01mWatt with maximum angular acceleration of 0.0427rad/s2. Efficiency of the Salter Duck prototype is 56%.

A Comparative Study of the Damping Force and Energy Absorbtion Capacity of Regenerative and Conventional-Viscous Shock Absorber of Vehicle Suspension

This paper presents a comparative study of the damping force and energy absorbtion capacity of a typical conventional-viscous and a regenerative shock absorber for vehicle suspension. Regenerative shock absorber (RSA) is a shock absorber which can regenerate the dissipated vibration energy from vehicle suspension into electricity. In this research, a prototype of regenerative shock absorber was developed, its damping force and energy absorbtion capacity were tested, and the results were analized and compared with those of a typical conventional-viscous shock absorber. The regenerative and viscous shock absorber were compressed and extended in various excitation frequency using damping force testing equipment to obtain force-velocity and the force-displacement curves. The force-velocity and force-displacement curves indicate the damping force and energy absorbtion capacity of the shock absorber. The results show that the damping force of the typical-viscous shock absorber closed to linear at all exciation frequencies. For regenerative shock absorber, nonlinearity and large hysteresis area of the damping force occur at all excitation frequencies. Further, the energy absorbtion capacity of the typical-viscous shock absorber shows an elliptical area with the compression part bigger than the extension one, while those of the regenerative shock absorber shows an asymmetric square area, which indicates a smaller energy absorbtion capacity. These phenomena indicate the significant effect of implementing dry friction damper and elctrical damper to the characteristics of regenerative shock absorber.