A man-machine interaction model for determining the safety of devices for harvesting at heights

Israel recently instituted new safety regulations requiring the use of a harness on agricultural high-altitude platforms. The benefit of these regulations is controversial, since although these platforms frequently roll over, there is often no severe damage to the worker. Farmers claim that the regulation requiring workers to fasten themselves to the platform with a harness will prevent operators from jumping from the rolling platform to protect themselves. This paper describes the advantages of a multi-body dynamic man-machine interaction model in investigating the benefit of harnessing the operator to the platform cell. Different working scenarios caused by the Afron three-wheeled platform and human reactions to rollover were simulated. A model of ground contact force during impact between soil and man was defined according to experiments on different surfaces. Simulation results show that the use of the harness did not improve the worker's safety conditions or decrease the severity of human injury significantly in comparison with the human injury incurred without the use of a harness. In fact, the operator may be protected by escaping from the platform cell and the harness prevents such an option during rollover. Thus the use of a harness on these agricultural platforms in conditions that may cause rollover does not reduce potential injury in comparison to that of unbelted operators.