The Apparent Vertical Filter Concept – Effects of Driving on a Slope

Abstract

Motion cueing in driving simulators is an important issue and still needs to be improved with respect to simulation quality. The constraints resulting from a limited space envelope impede the provision of accelerations that match those observed in a car identically. For example translational accelerations cannot be provided directly and need to be transformed to angular attitudes or scaled down depending on their characteristics. Current motion drive algorithms like the classic washout filter algorithm are using sets of high- and low-pass filters in combination with gain factors to answer this problem. But those filtering methods do not distinguish between the causes of accelerations with respect to the driving maneuvers. The Apparent Vertical Filter developed by the German Aerospace Center provides a different approach to this problem. The current paper gives an overview of how the problem of unwanted forces could be approached within a number of idealized maneuvers. The filter principle will be demonstrated for driving on a lateral slope. In contrast, the constraints of current filter methods will be discussed utilizing a classic washout filter as an example. Furthermore it gives an overview of how the apparent vertical filter deals with the problem and how it is structured. Finally, the responses of the two filter methods to a set of car model data are compared.