Modeling of hydraulic support system for large structures

Abstract

In the control of a large structure, hydraulic equipment is often used because it requires a large output. In this study, we focus on the telescope as an example of a large structure, and model its hydraulic support system and analyze its characteristics based on the proposed model. In recent years, the structure of telescopes and the size of the primary mirror have been increasing in dimensions. However, as a telescope is made of steel, changes in ambient temperature cause the structure to expand, thereby deteriorating its observational performance. To address this problem, a hydraulic system to adjust the deformation of the structure has been proposed. Traditionally, this design has relied on static performance studies and pre-installation adjustments. However, to implement the optimal design and achieve high performance, the structure and the system need to be considered in conjunction with each other. Therefore, it is necessary to represent the system in a dynamic and simple model. In this study, a new method for calculating the transfer function is proposed. First, the pipes, pistons, and accumulators are modeled to derive the low-order transfer function. Next, the transfer function is derived at a constant volume or pressure. Finally, the transfer function of the system in combination with the telescope mass is derived and evaluated.

Keywords

• large structure
• large telescope
• modeling
• piping
• piston
• accumulator
• transfer function
• hydraulic actuator