Intrinsic Safety – A New Design Approach for Safe Haptic Interfaces

The usage of haptic feedback in the control of vehicles and working machines promises beneficial options for steer-by-wire systems and increasing complexity of Human-Machine-Interfaces. On the other hand, the integration of force-feedback introduces new safety risks that have to be dealt with. This work introduces a new design approach for such kind of interfaces, limiting the force-feedback possibilities in such a way, that only safe states are assumed when a failure occurs. This is demonstrated on a force-feedback joystick with different variants including the change of joystick compliance, limiting gears and the combination of varying compliance and a break. The analysis shows that the selection of a suitable variant is strongly dependent on the interaction elements needed in the intended application.