Development of a Controller for a Front Loader of 3 Degree of Freedom: Improvement of Handling Ability of Agricultural Tractors

摘要

A computer controlled front loader was developed to improve handling ability of agricultural vehicles. Experimental front loader having one more degree of freedom than traditional one was constructed. Then computer controller was designed to guide a bucket of the front loader with following given straight or curved locus. Experimental results with a feed-forward based controller showed that the bucket of the front loader followed a given locus with positional error of 3 cm. To improve locus tracking ability, feedback control designed by taking account delay of hydraulic valves was introduced. By the introduction of feedback function the displacement from locus was reduced less than 2cm. Then the developed controller was used to assist human operator to handle a heavy object, and it was confirmed that inexperienced operators could handle a heavy object by use of a joystick.