液压缸非线性时变特性分析与数值仿真方法研究

Analysis of nonlinear time-varying characteristics and numerical simulation of hydraulic cylinders

以液压缸的运动特性为研究对象,首先通过揭示其非线性弹簧刚度呈现出软硬弹簧现象的产生机理,以及时变摩擦力处于负阻尼状态时引起"自激振荡"现象的原因,深入研究了二者耦合作用下液压缸的非线性时变动力学方程;而后,基于Taylor展开法将非线性动力学方程简化为可解的线性微分方程形式,并根据离散时域步长的原理反复迭代解决非线性弹簧刚度和时变摩擦力对液压缸运动特性的耦合作用问题;最后,采用Matlab软件编制数值仿真程序,模拟液压缸低速运动时的爬行现象。仿真结果显示,爬行现象模拟效果良好,且与以往解决非线性耦合问题的Van Der Pol-Duffing方程和Lienard方程相比,本文所提的数值仿真方法具有求解方便、适用性广,精度较高等优点。

To movement characteristics of the hydraulic cylinder as the research object, firstly reveals the non- linear spring stiffness presents the formation mechanism of hard and soft spring, and the time-varying friction is in a state of negative damping causes of the phenomenon of self-excited oscillation, further study of the hydrau- lic cylinder under the action of the two coupling nonlinear time-varying dynamic equation ; Then, based on the Taylor expansion method to simplify the nonlinear dynamic equations for the solvability of linear differential e- quation form, and according to the principle of discrete time domain step iterative solving nonlinear spring stiff- ness and time-varying friction on the coupling function of hydraulic cylinder motion characteristics ; Finally, u- sing the Matlab software of numerical simulation, the simulation of the hydraulic cylinder motion at low speed crawl phenomenon. The simulation results show that the creep phenomenon simulation effect is good, and with previous Van Der Pol - Duffing equation to solve the problem of nonlinear coupled and compared Lienard equa- tion, in this paper, the proposed numerical simulation method is easy to solve, wide applicability, and the ad- vantages of high precision.