Tilling depth control device of the rotary tiller which is attached to the tractor

摘要

PROBLEM TO BE SOLVED: To provide a lift control system for a working vehicle solving the problem that when a PID control is used in controlling the plowing depth of the implement of a conventional working vehicle, the operation regarding a D-action becomes excessive compared to other operations, resulting in vertical hunting of the implement and making the plowing depth control unstable instead.;SOLUTION: In the working vehicle having such a mechanism that the implement 40 is linked via a relevant mounting device 20, an implement lift means is connected to a control means 90 and the implement 40 undergoes lift control by the PID control, the lift control system works as follows: A derivative term is calculated using a primary delay system and an incomplete differential and so designed as to be approximately proportional to frequency when the frequency of height detection value is lower than a cutoff frequency( set frequency ), in contrast, decrease as the frequency increases otherwise.;COPYRIGHT: (C)2005,JPO&NCIPI