06 - Systems, Subsystems and EquipmentPID TUNING FOR MULTI-CHANNEL STRUCTURAL FATIGUE TESTING SYSTEMH.W. Zhao¹, S.H. Duan¹, J.M. Feng¹; ¹Aircraft Strength Research Institute of China, China The full scale aircraft structural fatigue test plays an important part in the process of new aircraft development. It is the basis for aircraft structure life prediction and crucial mean to confirm critical parts of structure and its repairing cycle. The loading spectrum is implemented to drive hydraulic setups by multi-channel coordinated loading control system in the test. There is interference between channels in the fatigue test system, so that load control error is bigger and test period is influenced. Low accuracy of PID parameters and low property of hydraulic equipment are mainly factors. How to consider coupling between control system, hydraulic system and mechanical system and how to simulate dynamic characteristic of hydraulic equipment and PID parameters are crucial problems in numerical simulation. For this, the thesis researched deeply structural fatigue test system by simulation technique, detailed works as follows:rn1) Mathematical model to fatigue test system was presented.rnStructural fatigue test setups consist out of three main systems, the hydraulic system, mechanical system and control system. This paper presented mathematical model of three systems and total system that reflecting coupling influence between three systems.rn2) Simulation of multi-channels fatigue test system was implemented.rnSingle channel, double-channel and triple-channel test system are considered as research Object. The dynamic characteristics of hydraulic equipme |