Contribution of inspection methods to monitoring operator comfort during agricultural operations

In agricultural activities, the tractor driver is subjected to many stresses from physical and attentional points of view. Driving tractors requires the operator to pay great awareness both during the agricultural operation and when handling the vehicle. The seat and the driving place play an important role by representing the interface between the man and the machine. In recent years, various investigation techniques have been used with the aim of studying the operator’s comfort during the mechanized operations. The techniques most aimed at observing posture and postural commitment examine the positions of specific body parts and their variation over time, the pressure measured between the body and the seat and the muscle electromyographs of the limbs and back. In this study, three driving modes have been considered: i) manual driving, ii) assisted driving and iii) semi-automatic driving in the execution of an agricultural practice of harrowing soil following plowing. Ten operators were hired to carry out the task on the same field alternating the three different driving methods. The procedure of investigation of the postures assumed by the body consisted in the application of a low-cost 3D camera (Microsoft Kinect), a continuous reading tool of the posture and of the crucial nodes of the body. For the evaluation of the pressures of the operator’s body on the seat, a sensitized carpet consisting of a matrix of sensors was used. Finally, portable electromyographs were placed in the shoulders, left arm and back of the operator for the assessment of muscle engagement. The values collected by the three methodologies were processed with multivariate analysis, to verify the contribution of each methodology in the characterization of the driving methods and in the measure of the physical correlated effort.