Design, Analysis and Testing of a Hydraulic Catapult System

A hydraulic catapult system is proposed to simulate the movement of the missile in the launch tube, which mainly consists of a high-speed hydraulic cylinder, an accumulator group, a main valve, a servo valve and a cable pulley mechanism. The key technical difficulties are that how to improve the response speed of main valve of big flux and increase the catapult speed in limited stroke. An ingenious controlled valve is designed and an cable pulley mechanism is applied to the hydraulic lever. The system working principle and design method are discussed. Then a system mathematical model is established, and the characteristics of the controlled valve and ejection process are further investigated through numerical simulation. Theoretical results are finally compared with the experimental ones, and it is found that they are in agreement. Finally, PID control is applied to the hydraulic catapult system, and the experimental results show that the hydraulic catapult can accurately track the velocity commands. This paper provides a valuable reference for improving high performance hydraulic catapult system in the aerospace field.