Development and testing of a system for monitoring field operational characteristics of a tractor draught control system with a field mounted implement : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University

Abstract

The conventional draught control system, as fitted to modern tractors, consists of a negative feed back control system that adjusts the working depth of mounted or semi mounted soil engaging implements in an attempt to regulate the draught requirements of the implement. The system has become important in agricultural production because it increases the efficiency of tractor operations in two ways. Firstly, by controlling the draught requirements of an implement the draught control system allows tractor engine efficiency to be optimised. Secondly, by transferring some of the weight of the implement onto the rear wheels of the tractor, wheel slip is reduced and controlled. This latter function, more than any other, was responsible for the major change in the design concept of tractors, permitting smaller, lighter tractors to do the same work as their heavier predecessors, pulling trailed implements. The control system has lead to the ability of relatively light weight tractors being able to maintain a high work rate (in terms of area cultivated in a given time) with acceptable working depth fluctuations, and without undue energy loss through wheel slip.