中文摘要：

对折叠式臂架系统变幅过程进行动力学仿真与分析，研究影响臂架变幅稳定的主要因素，通过优化控制系统设计，实现了臂架的平稳变幅。描述了变幅过程中机构的整体运动情况，针对变幅开始和结束时刻工作点的抖动进行仿真分析，得到了mark点的运动特性与位移曲线。表明臂架变幅稳定性主要取决于中臂双液压缸动作的同步性；对液压控制系统的控制参数进行调整，提出了臂架变幅的优化控制方案。优化后的方案提高了臂架变幅的稳定性，也对液压缸的动作精度要求大幅降低。

英文摘要：

Key factors that affect luffing stability of a common foldingboom arm system are investigated though dy namics simulation and analysis, and an optimized control strategy is proposed to achieve stable luffing process in this paper. The arm system movement in luffing process is described. The jittering of the working point at beginning and end moment of the luffing process is analyzed by simulation. Motion characteristics and displacement curves on the selected mark point are gained. The simulation results indicate that the main factor that affects arm luffing stabil ity lies on the action synchronization of the cylinders that drive the middle arm. An optimized control strategy is pro posed through parameter adjusting simulations. The field test results have shown that the arm luffing stability is clearly improved, and the demand on hydraulic cylinder＇s motion precision is greatly reduced.