Static Testing of Draft Sensor for Three Point Hitch Dynamometer Utilization

Abstract

This paper investigates the possibilities in design of universal three point hitch dynamometer. Approaches in diff erent hitch dynamometers are explained and pros and cons are mentioned. Also main parts and functional principle of dra sensor are clarifi ed. The main goal of this research is clarifi cation and examination of dra sensor output signal on angular dra force dependences. Utilization of dra sensor as a source for dra force sensing in lower arms is intended and examined. Research was focused on loading of dra sensor in diff erent directions for proper screening of voltage output. Special loading device was designed and used with respect of real mounting conditions and force loading identically to bearing pins of tractor hitch lower arms. With usage of calibrated load cell and National instrument sensing control unit stage loading diagram of dra sensor was obtained. Results show basic feedback of voltage output on force load angle variation. In non-load condition, voltage output fl uctuates around 5 V. In the main direction of dra force application voltage drop occurs from 5 V up to 3.16 V. Reverse direction of loading brings the voltage output increment from 5 V up to 7.06 V. When the load is applied with angular inclination voltage output changes are diminished up to 90° and dra sensor shows voltage output symmetry against the main axis. Based on stage loading diagram the appropriateness of dra sensor usage in design of universal three point hitch dynamometer is discussed in paper summary. Also further research opportunities and results application are suggested.