Analysis Of Multi-cylinder Smooth Lifting Mechanism And Hydraulic Control Characteristics

Aircraft manufacturing is a high-precision,difficult and high-tech "three-high" project.According to statistics,the aircraft assembly time occupies half of the total production cycle of the aircraft.Among them,the installation of aero-engine is a crucial part of the assembly of the aircraft.The application of an engine-mounted vehicle can effectively improve the installation quality and efficiency and reduce the manufacturing cost.The structure of the installation vehicle is divided into six degrees of freedom posture adjustment platform,vertical lifting mechanism and omnidirectional vehicle from top to bottom.The subject is aimed at the study of the vertical lifting mechanism.The mechanical structure and the hydraulic control system are designed,theoretically analyzed and simulated respectively,and optimized and corrected.The paper firstly consults relevant materials and literatures,based on the research status at home and abroad,and compares and analyzes the forms of various vertical lifting mechanisms and applicable occasions.Based on the requirements of the researched vertical lifting mechanism,the mechanical structure design is performed.Through the dynamics and kinematic analysis of the mechanical structure,the position of the maximum thrust of the hydraulic cylinder in the lifting mechanism and the maximum lifting speed of the platform and the key parameters affecting both are determined.Then the multi-objective genetic algorithm is used to optimize the position of the hydraulic cylinder’s articulated joints,effectively reducing the thrust of the hydraulic cylinder and the lifting speed of the platform,making the layout of the hydraulic cylinder more reasonable,the platform lifting more smoothly,and laying the foundation for the design analysis of the hydraulic control system of the following lifting mechanism.basis.According to the optimized mechanical structure and hydraulic control requirements,the hydraulic control system design is completed and its working principle is analyzed.According to the schematic diagram of the hydraulic system,the mathematical model of the reference loop in the system is established,the transfer function of the reference loop is derived,the dynamic characteristics of the system are analyzed,and the optimal values of the key parameters affecting the performance of the loop are obtained.The analog reference loop establishes the mathematical model of the slave loop,and then establishes a multi-cylinder synchronous analysis model.The selection of hydraulic components is completed,the main system parameters are determined,the actual dynamic characteristics of the reference loop in the hydraulic control system are analyzed with MATLAB/Simulink,the necessity for PID correction is given,and the dynamics of the synchronization system with PID control parameter adjustment under partial load conditions are analyzed.The impact of performance.The results show that the hydraulic control system can effectively improve the dynamic characteristics of the system by increasing the PID correction,making the hydraulic system better meet the control requirements.