Practical demonstration of a large-scale active vibration isolation system

Small experimental test-rigs are often used to investigate active vibration control concepts in the laboratory because of ease of construction and implementation. However, in marine applications, there is a large gap between this type of experiment and full-scale implementation onboard a ship. In this article a large-scale laboratory based active vibration control system is demonstrated. It involves a floating raft system attached to a hull-like structure by way of four hydraulic actuators, which are placed in parallel with eighteen passive resilient isolators. The flexible hull-like structure is supported on twenty six pneumatic springs to simulate a floating ship. A decentralized feedforward control strategy was implemented resulting in the reduction of vibration levels on the flexible hull-like receiving structure of up to 36 dB at some tonal excitation frequencies. The passive isolation results in broadband control and is most effective at higher frequencies.