تحقیق درباره سیستم هیدرولیکی لرزش گیر The Investigations of Hydraulic Heave Compensation System

1 Introduction Different operations made on the ocean can be difficult due to the occurrence of waves. Very often the ocean is rough, which causes that the operations of the vessel on the sea are very difficult and even dangerous. The most important operation performed on such ships are: lifting, lowering and maintaining the load on a constant level i.e., at a constant height relative to the seabed. Just for these reasons heave compensation systems are developed and applied. In the last few decades such systems have been deeply investigated, developed and implemented on many ships. Heave compensation solutions can be divided into three categories: passive heave compensation (PHC), active heave compensation (AHC) and active-passive (semi-active) system. The last one combines advantages of both AHC and PHC systems. The target of heave compensation system application is to reduce the load fluctuations and to improve the safety [1]. First active heave compensation system was presented by Southerland in 1970 and described in paper [2]. In this paper Authors presented that the proposed AHC system can be successfully used in handling operation made on sea vessels. A few years later, i.e. in 1973, the prototype of the passive heave compensation system for offshore drilling is tested. The results of the tests of these and other similar solutions allowed AHC and PHC systems to become extensively accepted in offshore industry. In 2008 Do and Pan studied for the first time a nonlinear controller for the AHC system [3]. They used an electro-hydraulic system with a double acting cylinder. The use of the disturbance observer in the system made it possible to reach a success. In active heave compensation system hydraulic and electric drives are most commonly used, but in passive compensators a pneumo-hydraulic drives are most commonly used. According to Nespoli et al. [4], hydraulic actuators (cylinders, motors) ensure the highest power to weight ratio of any other actuator. Moreover, the hydraulic drives applied in offshore application are well tested showing high reliability. The paper is organized as follows. After the introduction, a review of the state of the art in the area of passive, active and hybrid system are given in Sect. 2, in which examples of these systems are described. Their advantages and disadvantages have been mentioned. In Sect. 3 the solution proposed by authors are presented. The experimental and simulation results are included. Conclusion and future work is presented in Sect. 4. In this paper the Authors described built simulation model of the electrohydraulic servo drive. The Authors of this paper performed basic experimental and simulation investigations of an active heavy compensation system. Simulation model is built using Simulink SimHydraulics tool. The basic simulation research are shown for different parameters of the sine signal. Position of the hydraulic cylinder and hydraulic motor are measured.