Masters Theses

Date of Award

8-1982

Degree Type

Thesis

Degree Name

Master of Science

Major

Biosystems Engineering Technology

Major Professor

Fred D. Tompkins

Committee Members

Luther R. Wilhelm, Bobby L. Bledsoe

Abstract

A 100-pto-horsepower agricultural tractor was instrumented with a microcomputer-based data acquisition system for monitoring energy inputs to implements powered by the tractor. The data acquisition system included instrumentation for measuring and recording fuel consumption, implement draft, travel speed, angular velocity of each drive wheel axle, and torque on each drive axle. Drive wheel slip, fuel consumption per unit time and area, drawbar horsepower, axle horsepower, tractive efficiency, and implement energy requirement per unit area could be subsequently computed from these measurements.

The data acquisition system was installed on a 2675 Massey- Ferguson (two-wheel drive) tractor. The system was centered around a DEC PDP11/03-LK microcomputer that was installed in a rack above the head of the operator. A DEC TU58 cassette tape system, which incorporated dual tape drives, was used for system program and data storage. Communication between the operator and data acquisition system was through a 64-key keyboard and a compact CRT unit for external monitoring of program execution and data display. Other components of the data-handling system included a microprocessor counter box for summing digital signals and a strain gauge signal conditioner/amplifier. All electronic data handling components were mounted within the confines of the tractor cab. The sensing hardware on the instrumented tractor consisted of a fuel transducer and display, a three-point hitch drawbar dynamometer, a free-rolling fifth wheel to indicate travel speed, axle speed indicators, and axle torque sensors. Power for the data handling equipment and sensing transducers was supplied by a portable gasoline generator mounted on the front of the tractor.

The instrumented tractor was used during two cropping seasons to measure energy inputs to selected tillage and planting implements. Implements included a subsoiler, chisel plow, heavy tandem disk harrow, light tandem disk harrow, soil pulverizer, cultimulcher, row-crop planter, and no-till row-crop planter. Implements were operated to simulate the cultural practices associated with conventional seedbed preparation and planting.

The procedure for data collection consisted of operating a given implement with the instrumented tractor over measured 200-ft plots. The data acquisition system sampled and recorded the monitored parameters at one-second intervals during the test run. Each of the implements, except the subsoiler and row-crop planter, were operated at three travel speeds to obtain a range of energy requirements associated with implement operation. Field data were reduced by averaging numerous test replications of each operating speed-implement combination to obtain mean values for the desired energy-related parameters.

The data acquisition system performed satisfactorily with some modifications. Results of the field measurements indicated that the drawbar pull, drawbar power, drive wheel slip, fuel consumption per unit time, and the energy input per unit area processed all tended to increase for each implement as the travel speed was increased. However, the quantity of fuel required to process a unit area tended to decrease slightly for a given implement as the travel speed was increased.

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