07 - Systems, Subsystems and Equipment
STUDY ON CLOSED-LOOP CROSS COMPENSATION CONTROL TECHNOLOGY IN ACCELERATED FATIGUE TESTING
H. Zhao, Aircraft Strength Research Institute of China, Xi’an jiaotong Un, China; H. Tao¹, Z. Gu, Chongqing Hongyu Precision Industrial Co., Ltd., China; G. Shi, Shenyang Aircraft Design & Research Institute of China, China; S. Duan¹, J. Feng¹; ¹Aircraft Strength Research Institute of China, China
A Aircraft structural fatigue test is a multi-component and multi-channel system, in which there are usually a large number of channels with significant interactions among them. Control is made more difficult because the tests are run in load control and the load cells usually move with the actuators. But fatigue test speed is limited mainly by this effect. To solve this problem, a closed-loop cross compensation control technique is proposed in this paper. Firstly, the Stiffness Coordinate Matrix (SCM) among the channels was deduced. Furthermore, the Cross Compensation Matrix (CCM) was derived by this matrix. Subsequently, CCM was introduced into the closed feedback control loop, and a cross compensation control algorithm was designed. Using that algorithm, the output signal of every channel was compensated crossly and adaptively in the aim to decrease the coupling effect among channels. At the same time, Hurwitz stability criterion was used to verify the stability of the new method. In order to validate the method in this paper, the technology using commercial off-the-shelf control techniques were implemented on a four channels full-scale fatigue testing system for wingbox structure of the MTS SYSTEMS. Results of the experiment showed that the method presented in this paper was efficient and reasonable to improve the efficiency of aircraft structure fatigue test, and could be widely used in relative test article. Some important findings may emerge from the future discussion and analysis.