Design and numerical modelling of a novel mechanical isolator for floating systems

Lidar technology is widely used in marine applications for environmental research and offshore wind assessments, providing crucial data on wind speed and direction. The Lidar can be assembled on fixed or mobile platforms. When installed on floating buoys, the motion caused by sea waves affects the measurement accuracy of the Lidar. To solve this issue, a mechanical isolator is designed to decouple the Lidar from buoy movements. This thesis focuses on design, numerical modelling and analysis of a new mechanical isolator specifically developed for floating systems. The isolator is designed in 1:2 scale and consists of two subsystems: a heave isolator and a pitch-roll isolator. The heave isolator is inspired by vibration isolation and is designed to achieve zero equivalent stiffness in the vertical direction. The pitch-roll isolator,instead, is based on a double-pendulum mechanism, reducing motions by minimizing the natural frequency of the system. A detailed model is developed using MATLAB and Simscape Multibody to optimize the design and evaluate the performance of the isolator. Through numerical simulations, the efficiency of the system in reducing the Lidar motion is assessed, considering different wave frequencies and amplitudes. The results produced by this paper demonstrate a significant reduction in the transmission of wave disturbance to the Lidar, leading to improved measurement accuracy and providing a valuable reference model for experimental validation.