Safety concepts for autonomous and semi-autonomous mobile work machines

Development of autonomous mobile work machines is on the agenda of increasing number of machine vendors since the customers’ interest has also increased significantly. Autonomous mobile work machines are operating in closed environments. Compared to the applications currently available, introduction of the current technologies in outdoor mobile work machine systems is more complex than what it may seem, since sensors operate well only indoors, safety of the outdoor sensors is limited and the safety requirements are not unambiguous. Increase in the level of automation sets more requirements to the system and also increases the responsibility of the manufacturer. A situation where manual and automated machines operate simultaneously in the area presents challenges from the safety point of view, since both human errors and machine failures may cause hazardous situations. The means for better safety include detecting persons and machines, applying access control systems for machines and humans, limiting allowed machine movements and speed, enabling movements by applying suitable devices, increasing situational awareness of machines and persons, and defining proper rules for humans and machines. Risk assessment is an essential tool in selecting suitable methods for the specific application. This paper introduces the approaches relevant for mobile machine vendors in considering the safety on the path towards an autonomous system.