Vibration mapping of walking and riding type power tillers

Abstract

The major excitation of the vibration of the power tiller is the unbalanced inertia force of the engine. Further vibration exciting forces are the transmission system. The mechanical vibration is transmitted to the human body through the handle and seat. The magnitude of mechanical vibration at different components of the power tiller system is essential for identifying the source of vibration and providing vibration isolators to increase the safe exposure limit of operators. The mechanical vibration of walking and riding type power tillers was measured at different locations in stationery condition, during rototilling in untilled and tilled soil and in transport mode on bitumen and farm roads. Comparing the acceleration at the different locations, the vibration at the top of the engine was highest followed by chassis, handle, root of handle bar and gear box for both walking and riding type power tillers. In stationary mode the increase in engine speed resulted in two fold increase in machine vibration at handle for both power tillers. Among the power tillers the vibration at handle was higher by 72.94 to 170 percent for the riding type power tiller. In field operation and transport mode the increase in forward speed of operation resulted in increased values of acceleration. The magnitude of vibration was higher at handle (40.50 percent) and seat (28.08 percent) in unfilled field than tilled field. In transport mode farm road induced higher vibration than bitumen road. Among the power tillers the vibration induced in walking type power tiller was higher during field operation whereas in transport mode power tiller (8.95 kW) exhibited higher values.