Experimental and Theoretical Consideration on Nonlinear Vibration of the Japanese Head-feeding combine

为了研究联合收割机的振动特性是周期、半周期还是混沌，在日本半喂入式联合收割机的静止和收割条件下进行了试验，分别测量了该机重心位置处的6个自由度加速度分量和驾驶座位置处的3个自由度加速度分量。最后，通过对联合收割机的加速度时间序列数据的功率谱密度、相轨迹、Poincare截面和Lyapunov指数进行分析，得到以下结论：1.联合收割机在静止状态（发动机、脱粒机和切割机均处于非收割状态）下的振动主要受发动机的影响。此外，除了发动机驱动频率分量（45 Hz）之外，还观察到发动机的1/2、1/3（次谐波）频率分量。从这些结果 ...更多信息 2.联合收割机在收割工况下的振动受发动机、收割机和驱动装置的影响。也就是说，与稳态条件相比，在收割过程中观察到了一些振动频率成分。此外，除了发动机驱动频率分量之外，还观察到发动机的1/2、1/3（次谐波）、2/3频率分量，与静止条件相同。根据这些低频分量的存在，估计收获条件下的振动特性为具有某些频率分量的半周期非线性振动; 3.由于李雅普诺夫指数为-1.0 - -3.0 10 ^，且不存在倍周期分岔，因此未识别出混沌振动的存在; 4.应考虑次谐波等低频<-3>分量从人的技术角度进行简化，以设计出具有舒适乘坐品质的联合收割机。少

Experiments under the stationary and harvesting conditions of the Japanese head-feeding combine, were performed in order to investigate whether the vibration characteristics of the combine featured periodic or semi-periodic or chaotic.Therefore, 6 degrees of freedom components of acceleration at the location of the center of the gravity, and 3 degrees of freedom of acceleration at the location of the operator seat were measured independently. Finally, vibration characteristics of the combine were estimated with the power spectrum density, phase trajectory, Poincare section, and Lyapunov index of the time series data of accelerations.From this research, the following results were obtained.1.Vibration of the combine under the stationary condition (engine, thresher and cutter are driven without harvesting) are mainly influenced by the engine. Further, 1/2,1/3 (subharmonics) frequency components of the engine are observed besides engine driving frequency component (45Hz). From these result … More s, Vibration characteristics under the stationary condition are estimated to indicate semi-periodic nonlinear vibration.2.Vibration of the combine under the harvesting condition are influenced by the engine, threshing unit and driving unit. Namely, some kinds of vibration frequency components in harvesting are observed compared with stationary condition. Further, 1/2,1/3 (subharmonics), 2/3 frequency components of the engine are observed besides engine driving frequency component as same as stationary condition. From existence of these low frequency components, Vibration characteristics under the harvesting condition are estimated to indicate semi-periodic nonlinear vibration with some kinds of frequency components.3.Existence of the chaotic vibration was not recognized due to Lyapunov index whose valuse are -1.0 - -3.0*10^<-3> and due to without existence of period doubling bifurcation.4.Low frequency components such as subharmonics should be reduced from the viewpoint of the human technology in order to design combine harvester with comfortable ride quality. Less