Analytical study of self-excited vibration on single degree of freedom vibratory-tillage

Analytical and experimental study on vibratory tillage by adding external energy to the tillage tool has been widely conducted. Though this method has been shown to significantly reduce soil resistance, it will, unfortunately, increase the energy consumption excessively. Experimental study on vibratory tillage by self-excited vibration method has also been performed. This method can also reduce soil resistance though not as much as the former. No analytical study of the latter, however, can be found. This paper discusses analytical study of self-excited vibration of tillage-tool on vibratory tillage due to natural excitation of varying cutting forces. The objective of this discussion is to find dynamics parameter of vibratory tillage so the vibration of tillage-tool will be able to reduced draft force required for loosening soil density during tillage operation The Vibration of vibratory tillage was modeled as a vibration with Single Degree of Freedom (SDOF) system. The tillage-tool was connected to an implement by an elliptic spring while the natural excitation of the varying cutting force was modeled as a periodic function, which can be expressed as a Fourier series. The elasticity of elliptic spring and the inertia of tillage tool were optimized such that the tillage-tool vibrates violently around its resonant frequency. This condition decreases both the soils resistance and the draft force required to loosen soil density due to self-exited vibration during tillage operation. The possibility of draft force reduction was investigated further by analyzing time response of the displacement and by analyzing the oscillating pathway of the tine tip.