Design and Development of Electro Hydraulics Hitch Control for Agricultural Tractor

Tractor hitch control system is used for attaching and operating various Agricultural Implements and for operating tipping trailer. The system has also got provision to attach additional Aux valves for rear and front mounted attachments. The rear mounted implements are coupled to the tractor using Three Point Linkage (3PL) System. The hitch hydraulics system consists of hydraulic pump, filter, piping’s, fittings and hydraulics lift unit. Hydraulics lift unit consists of a proportional control valve, cylinder, piston and power linkages. Conventional control valve is hydro mechanical part operated by mechanical linkages. The control valve and linkages plays major role in performance of hydraulics system. Hydraulics is required to operate in extreme conditions of soils such as very soft like sand to very hard like black cotton sand. These two extreme conditions makes linkage and control valve optimization work very challenging and very difficult to get single solution for soft and hard conditions. In addition to best performance requirements, lesser power loss and operating effort are also important for customer satisfaction. To meet this challenge of high on performance in all soil conditions, effortless operation, high on efficiency (less hydraulics power loss) and aesthetics, Electro Hydraulics Hitch is the best solution.

In the present work, Electro Hydraulics Hitch System is designed and developed for Agricultural Tractor to replace conventional hydro mechanical hitch. This system consists of specially made control valve manifold using Solenoid Valves, Hydraulic Control Unit (HCU), Position Sensor, Draft Sensor (Load Cell) and input levers with sensors. They are connected by using suitable wiring harness. The system is having all features functions i.e. Position Control (PC), Draft Control (DC) and Quick Lift (QL) of conventional system. The basic common valves like, Pressure Relief Valve (PRV), Check Valve (CV), Shock Load relief Valve (SLRV), Isolator valve and Tipping trailer port are adopted from current design. The customer touch points are maintained same as that of conventional type i.e. PC, DC levers and QL button.

The work also includes analysis and optimization using Simulink Matlab, performance tests in lab and fields for proving in various soil conditions.