Novel draught resistance sensing elements for measurement of drawbar power of agricultural machinery

Aim of study: To develop an instrumentation system comprising three force sensing elements to measure the draught resistance of any tillage and seeding tools during field operation by connecting one sensing element to each three-point linkage of the tractor. Area of study: Department of AgFE, Indian Institute of Technology, Kharagpur, India Material and methods: Commercial S-type transducers were packed laterally in between the curved plates perpendicular to the direction of travel in such a way that the magnitude of the imposed force decreased and its nature got reversed consequently during tillage force measurement. Finite element analysis was also performed on the proposed model of the sensing elements. The performance was evaluated on the basis of non-linearity, hysteresis, and non-repeatability. The data were validated with the draught values simultaneously recorded using instrumented three-point linkages of tractor. Main results: It offered good sensitivity and linearity during static calibration. The measurement capacity based on maximum applied load during static calibration was 10 kN with accuracy 93.40%. The low values of mean percentage error (9.03%), maximum absolute variation (17.43%), and root mean square error (0.51 kN) revealed good accuracy of the system. Validation was conducted by comparing the data for an offset type disk harrow with the model outputs of previous studies to assess its suitability for other soil working conditions, and the results were satisfactory. Research highlights: The advantages of this sensing device in the measurement of drawbar power are fewer changes in the hitching geometry, lower cost, and capability of quick hitching.