摘 要
首先介紹了液壓挖掘機的一個改裝的電動液壓的比例系統(tǒng)。根據負載獨立流量分配（ LUDV ）系統(tǒng)的原則和特點，以動臂液壓系統(tǒng)為例并忽略液壓缸中的油大量泄漏，建立一個力平衡方程和一個液壓缸的連續(xù)性方程?；陔妱右簤旱谋壤y門的流體運動方程，測試的分析穿過閥門的壓力的不同。結果顯示壓力的差異并不會改變負載，此時負載接近2.0MPa。然后假設穿過閥門的液壓油與閥芯的位移成正比并且不受負載影響，提出了一個電液控制系統(tǒng)的簡化模型。同時通過分析結構和承重的動臂裝置，并將機械臂的力矩等效方程與旋轉法、參數估計估計法結合起來建立了液壓缸以等質量等為參數的受力平衡參數方程。最后用階躍電流控制電液比例閥來測試動臂液壓缸中液壓油的階躍響應。根據實驗曲線，閥門的流量增益系數被確定為2.825×10-4m3/(s•A)，并驗證了該模型。


關鍵詞：挖掘機，電液比例系統(tǒng)，負載獨立流量分配（ LUDV ）系統(tǒng)，建模，參


Abstract
A retrofitted electro-hydraulic proportional system for hydraulic excavator was introduced firstly. According to the principle and characteristic of load independent flow distribution (LUDV) system, taking boom hydraulic system as an example and ignoring the leakage of hydraulic cylinder and the mass of oil in it ,a force equilibrium equation and a continuous equation of hydraulic cylinder were set up. Based on the flow equation of electro-hydraulic proportional valve, the pressure passing through the valve and the difference pressure were tested and analyzed. The results show that the difference of pressure does not change with load and it approximates to 2.0MPa. And then, assume the flow across the valve id directly proportional to spool displacement and is not influenced by load, a simplified model of electro-hydraulic system was put forward. At the same time, by analyzing the structure and load-bearing of boom instrument, and combining moment equivalent equation of manipulator with rotating law, the estimation methods and equations for such parameters as equivalent mass and bearing force of hydraulic- cylinder were set up. Finally, the step response of flow of boom cylinder was tested when the electro-hydraulic proportional valve was controlled by the step current. Based on the experiment curve, the flow gain coefficient of valve unidentified as 2.825×10-4m3/(s•A) and the mode is verified.