A novel wireless instrumentation system for measurement of PTO (power take-off) torque requirement during rotary tillage

Abstract

A wireless instrumentation system was successfully developed and tested to overcome the constraints associated in collection of torque data of PTO-driven agricultural machinery with benefits such as no disturbance in telescopic action or vertical inclination of Cardan shaft. The system ensured no alterations in standard length of PTO driveline shaft. Further, telemetry system enabled remote acquisition of signals without inducing any risk of damaging the associated electronic components. It offered sensitivity of 1.6 mV/V per kN-m of applied torque with good linearity during static calibration. The performance was assessed based on accuracy, non-linearity, hysteresis, and non-repeatability and their values were 97.06%, 2.57%, 3.44%, and 0.26%, respectively. The data obtained for torque were validated with the torque computed from axial and radial load data of PTO ball bearing acquired simultaneously during rotary tillage. The low values of mean absolute percentage error (7.78% and 6.58%), maximum absolute variation (15.17% and 15.39%), and root mean square error (21.24 and 22.16 N-m), indicated good accuracy of the system. The experiments were designed with active tillage tools having two different numbers of blades, transmission gear ratios, engine speeds, tyre sizes, and four working depths as treatments. Results revealed that considered variables other than tire size, significantly affected the PTO torque and power. The decrease in PTO torque and power was found to be levelled off beyond velocity ratio 7.92. The developed instrumentation technique is simple, reliable and could be useful for database generation, implement design, and matching for effective utilization of tractor engine power. • Novel instrumentation technique was used to measure PTO (power take-off) torque. • It does not disturb the telescopic action or vertical inclination of Cardan shaft. • Sensitivity 1.6 mV/V per kN-m of applied torque with good linearity in calibration. • Data validated with torque computed from axial and radial load of PTO ball bearing. • The low values of MAPE, MAV, and RMSE indicated good accuracy of the system.