Accurate guidance of towed implements is important for performing agricultural field operations and for gaining the ultimate benefit from an agricultural automatic guidance system. The study of open and closed loop system responses can be helpful in the design of practical guidance controllers. A dynamic model of a tractor and a towed implement system was developed. Open loop analysis of the ki...

Measurement of the values of forces in tractor arms is of great importance due to draft of agricultural equipment. These values can be used for testing and evaluation of the agricultural machinery, selection of suitable tractor, etc. The tools which are used for measurement of the forces are called dynamometer. The main objective of the present study was to design and evaluate a load cell for i...

In a typical automatic guidance system for agricultural machines, the guidance system controls only one degree of freedom; either the steering angle of the front wheels of the tractor or other steering equipment is used for steering. In a tractor with the multiple degrees of freedom, like four wheel steering, the guidance system may use both the degrees of freedom for path tracking. However, th...

Tractor hydraulic power is used on a wide range of agricultural implements; however, the availability of operational hydraulic data at points other than full engine throttle position is limited. Operators could utilize this hydraulic data to maximize field efficiency and minimize machinery costs when determining suitable machinery for field operations. A field usable hydraulic test apparatus ca...

This work analyses the market value of second hand agricultural tractors in Spain for the period 1999-2002, with the aims of obtaining the most appropriate valuation models (through the use of ordinary least squares regression) and proposing an empirical model that estimates the true depreciation of these vehicles. Differences in tractor depreciation were studied in terms of the three horsepowe...

Since the mid 1990’s, advances in global positioning systems (GPS), microprocessors, actuators, controllers, plant/soil sensors and geographical information systems (GIS) have spawned the development of new, site-specific, variablerate techniques for chemical applications. At the same time, agricultural production has embraced other new technologies that increase the productivity of mechanized ...

A new method is described that can be used to decompose human controlled agricultural operations into an autonomous tractor. Four main levels of subsumption have been identified: Operation, Task, Optimisation and Primitive Actions where each level is subsumed by the level above. Tasks were classified into two distinctive roles, deterministic tasks that can be planned and optimised before the op...

In order to quantify tractor driver Whole-Body Vibration (WBV) induced by some of the agricultural operations, the ISO 2631 standard was utilized. Detailed methodology of the calculation of the WBV evaluating indices using the time-domain acceleration data analysis was presented. According to the results of the study, typical weighted root mean square (WRMS) value of the Z-axis vibration was mo...

The driving speed of modern tractors increased within last years up to 60 km/h. Together with the driving speed, the safety and comfort requirements are increasing as well. Since modern agricultural tractors still don’t have a rear axle suspension, their driving dynamics behaviour can become critical at certain situations. To be able to predict such critical situations, a multibody model of a t...