| Electro-hydraulic load simulator(EHLS) is a Hardware-in-the-loop simulation equipment on ground. It is applied to check the qualification of rudder driving system by simulating aerodynamic load spectrum to the flight device rudder. Therefore, it is significant to national defense and military industry.As EHLS is a typical passive force (torque) servo control system, when it is running, the active motion of rudder will have a disturbance to loading system which is connected to the rudder. This disturbance results in forced flow between cavities of loading motor. As a result, the extra torque appears. The extra torque is known for its large power, existence at times and the variation caused by motion of rudder. These characteristics affect the performance of EHLS severely. Therefore, how to restrain extra torque and improve the loading performance is key technology in the study of EHLS.After synthesizing numerous related literatures and reference materials home and abroad, the development of EHLS system is summarized. The studying direction and content are decided by analyzing the merit and shortcoming of related products and studies.First, the fourth and fifth order mathematical model of EHLS system is built. Then the system identification and verification are made. The result shows that the fourth mathematical model has equal quality to fifth order model when system is working under the normal work condition. Then genetic algorithm identification based on backstepping theory is proposed, which makes the result of identification more close to physical system. Then the proposed method is used for the fourth order model. Verification result proves the effectivity of the method.The generating mechanics and characteristic of EHLS extra torque is analyzed according to the system model. Considering the forced flow of system, adjustable throttle to solve the extra torque is proposed, and the mathematical model with adjustable throttle is built. The simulation result shows using adjustable throttle can relieve forced flow, and the extra torque can be restrained as a result.To solve the extra torque which caused by movement of rudder system, the neural network compensation control strategy is proposed. It is used to compensate the disturbance of rudder system. Each order of states of the rudder output is taken as neural network inputs. Compensator changes its output according to extra torque and compensates the load system to restrain the extra torque. Then the simulation comparison among PID controller, structure invariability and the proposed controller is given. The result shows the proposed method's effectivity. Aiming at the coupling between load system and rudder system, a adaptive backstepping controller with parameters variation adaptometer of EHLS is proposed. The complex system with high order is decomposed into a serial of simple low order subsystems. Then the controllers are designed for each subsystem. By doing these, the coupling relationship is passed to the system controller as a result. The variation of main parameters is considered at the same time, and parameters variation adaptometer is designed. The simulation results under different conditions show that the proposed controller can restrain extra torque effectively, and the load performance is finally improved.Experiments are made on the EHLS principle model machine. The extra torque generating mechanics and influencing factors are verified at first. Then experiments about neural network compensation controller and backstepping adaptive controller are made on the system. The performance about restraining extra torque and loading tracking of these two controllers are tested. The results show the controllers'effectivity. The experiments about adjustable throttle are made at last, the result shows its effectivity. |
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