【正文】 2。并且寫成如下式子： (10)J1, J2 和 J3分別是動臂，斗桿和鏟斗對各自的中心的慣性力矩；它們的值可以通過模擬動態(tài)模型得出J1=m，J2=m，J3=m。比較方程（9）和Fc=mac，可以得出點B的等效質(zhì)量： (11) 液壓缸負載的估算 工作裝置對于O1等效力矩等式為： (12) 其中和分別表示O1點到 G1180。 ，G2180。和 G3180。三點的距離；那么反力負荷為： (13)流量傳感器可以測量泵的流量。用于這項工作的儀器為多系統(tǒng)5050型。動臂液壓缸流量的階躍響應(yīng)在電液比例閥控制下的結(jié)果如圖5所示。同時，該曲線驗證等式(11) 。根據(jù)實驗曲線和等式(1)和(4)可確定KqKl的范圍。那么根據(jù)圖4中的數(shù)據(jù)我們可得出：KqKl=104m3/(sA) 。流量（L/min）時間圖5 動臂液壓缸流量的階躍響應(yīng)在電液比例閥控制下的曲線圖5 結(jié)論（1）電液控制系統(tǒng)的數(shù)學(xué)模型是根據(jù)挖掘機的特點發(fā)展起來的。假定流過閥的流量與閥口大小成正比，并忽略液壓系統(tǒng)的內(nèi)部和外部泄漏影響。簡化模型可以得到： ，其中Y（s）和Xv(s)分別是活塞和閥芯的位移。（2）從電液控制系統(tǒng)的模型中，我們可以得到等效的質(zhì)量，承載力，流量增益系數(shù)的值KqKl=104m3/(sA)，其中KI 是電液比例閥的增益系數(shù)。出自：中南大學(xué)學(xué)報（英文版）2008年第15卷第3期382—386頁Modeling and parameter estimation for hydraulic system of excavator’s armHE Qinghua，HAO Peng，ZHANG DaqingAbstractA retrofitted electrohydraulic 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 electrohydraulic 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 . And then, assume the flow across the valve id directly proportional to spool displacement and is not influenced by load, a simplified model of electrohydraulic system was put forward. At the same time, by analyzing the structure and loadbearing of boom instrument, and bining 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 electrohydraulic proportional valve was controlled by the step current. Based on the experiment curve, the flow gain coefficient of valve unidentified as 104m3/(sA) and the mode is verified.Key words: Excavator, Hydrauliccylinder proportional system, Load independent flow distribution (LUDV) system, Modeling, Parameter estimation1 IntroductionFor its high efficiency and multifunction, hydraulic excavator is widely used in mines，road building, civil and military construction，and hazardous waste cleanup areas．The hydraulic excavator also plays an important role in construction machines．Nowadays, macaronis and mobilization have been the latest trend for the construction machines．So，the automatic excavator gradually bees popular in many countries and is considered a focus．Many control methods can be used to automatically control the manipulator of excavator．Whichever method is used, the researchers must know the structure of manipulator and the dynamic and static characteristics of hydraulic system．That is, the exact mathematical models are helpful to design controller． However, it is difficult to model on timevariable parameters in mechanical structures