Ergonomical evaluation of 9 hp self-propelled multi-purpose planter cum sprayer

The ergonomic performance of a self-propelled multipurpose machine in planter-cum-sprayer mode was evaluated using hand grip levels (No Grip, General Grip, Soft Grip) and forward speeds of 2.0, 2.5, and 3.0 km h⁻¹. Experiments were conducted under a Central Composite Rotatable Design, and responses HAV, heart rate, BPDS, ODR, and sound level were analysed using RSM in Design Expert 13.5. Quadratic models were found significant (p<0.05) with strong predictive accuracy (R² = 0.93-0.97). Hand grip had the dominant influence on HAV, BPDS, and ODR, while forward speed significantly affected heart rate and noise level. Optimal ergonomic conditions were achieved at low grip intensity and moderate operating speed, minimizing discomfort and vibration exposure. The study confirms the role of controlled operating parameters in reducing physiological and ergonomic strain during planting operations.