| As diesel engines’ heart, the crankshaft is the key component of shipbuilding and automobile engines, and the medium and large full-fiber crankshaft with good mechanical properties and high reliability is essential for the stability and safety of automobile and ship. Full-fiber crankshaft forging hydraulic press is special forming equipment to produce full-fiber crankshaft, whose upsetting system’s synchronous control performance of double drive hydraulic cylinder and coordinating control performance of upsetting cylinder-bending cylinder have a great influence on molding efficiency and quality of full-fiber crankshaft. it needs to focus on the hydraulic control performance of the adverse effects including the hydraulic system nonlinear and load disturbance to improve the synchronous control and coordinating control performance. In this paper, the synchronization and coordination control of full-fiber crankshaft upsetting-bending hydraulic press has been studied, which has theoretical guidance and practical significance to improve control performance of the hydraulic press. The research in this paper is carried out as follows:(1) The three-dimension model of full-fiber crankshaft forging hydraulic press has be established, it is analyzed whose composition, structure and processes of the hydraulic press. Two input and output coupling mathematical model of the hydraulic press synchronization control system and mathematical model of bending system have been built by the mechanism modeling, whose simulation model has been established by MATLAB/Simulink as well. The effect of the dead zone of electro-hydraulic proportional valve and the leakage of upsetting cylinder on synchronization control performance has been mainly studied. Besides, it is studied that two-channel load force of synchronization control system have coupled interference to the displacement output of the respective channel.(2) On the coupling existed in synchronous control system, decoupling control strategy has been studied and simulated. The transfer function of the synchronous control system is transformed into the standard V specification. The mathematical model of compensating and decoupling links is established by input and load disturbance decoupling control method based on feedback compensation. The corresponding simulation is carried out, and the control effect of the decoupling method is analyzed.(3) Considering the characteristics of load disturbance of synchronous control system, Due to the weak robustness of the traditional fixed gain PID controller in the synchronous control of the system, a cross coupled fuzzy PID controller with good robustness and adaptability is designed, which is combined with the decoupling control algorithm, and simulation research is carried out to analyze synchronous control performance on the synchronous control system under the action of multiple types of partial load. It is analyzed for the bending and upsetting cylinder coordinate control by the master-slave PID upsetting-bending coordinated control strategy based on velocity feedforward.(4) Synchronization control system experimental platform is established. The influence of the same type load force on the synchronous error of the hydraulic cylinder is studied by experiments, The principle experiments is carried out for Coupling characteristics of synchronous control system, cross coupled fuzzy PID controller, master-slave PID coordinated control method based on speed feedforward to verify the feasibility of the theory and control strategy in this paper. |
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