Real Time Decision Making For Driverless City Vehicles.doc

REAL TIME DECISION MAKING FOR DRIVERLESS CITY VEHICLES

2. DEFINITIONS AND APPROACH 2.1 Solution Requie!ent"# De$i"ion M%&in' In(ut %n) Out(ut 2.1.1 2.1.1 De$i"ion De$i"ion M%&in' M%&in' Requie Requie!ent !ent"* "* The specification of requirements is a

fundamental part of the development cycle of any complex system, in order to enable its verification and validation . Regarding Regarding the developmen developmentt of the real-time decision decision making making module, module, the specification of requirements is crucial. Without a specification for this module, the impleme implementa ntatio tion, n, and eventu eventually ally human human lives lives ill ill depend depend on the softar softaree developers! interpretation of requirements, ithout the possibility to prove the functional correctness. " discussion on ho to develop a correct, unambiguous and complete specification for the decision making module for driverless city vehicles is beyond the scope of this ork. #oever, ithout the loss of generality, it can be assumed that such a decision making specification requires the decision making module to respond to certain traffic conditions in a defined ay, i.e. certain traffic conditions imply the execution of certain driving maneuvers. The occurrence of any traffic condition is modeled in this ork by a set of  discrete events. These discrete events are sent to the decision making module in

the form of World World $odel %vents. &epending &epending on a defined defined set of discrete events, the specification defines hich driving maneuvers can be performed safely. Table ' shos examples of such discrete events. " detailed and complete specification ould probably lead to a table containing thousands of such discrete events and driving maneuvers. (onsequently, the decision making module is modeled as an event-driven system )*+. #aving in mind the complexity of city traffic, a complete specification for a typical decision making module ill consist of a large number of defined inputsi.e. discrete events, and a large number of outputs i.e. driving maneuvers, hich are logically interrelated in a complex ay. TA+LE TA+LE I E,AMPLES OF DISCRETE EVENTS OF RELEVANCE.

REAL TIME DECISION MAKING FOR DRIVERLESS CITY VEHICLES

&iscrete %vent

%xplanation

/ stopped vehicle in front 0/ oncoming lane free */ pedestrian in front . . .

1topped vehicle as detected in front. The oncoming lane is obstacle free. 2edestrian crossing the road. . . .

2.1.2 In(ut 1*   The World $odel/ The World $odel represents the driverless

vehicle!s vie of its road environment. Therefore, it represents an input to the decision making module. The World $odel merges a priori given information e.g. road infrastructure ith traffic features hich are perceived during the vehicle!s movement e.g. dynamic obstacles. The data contained in the World $odel is constantly updated in real time and provided in to forms/ as World $odel %vents, and additionally in the form of an ob3ect-oriented structure.

" World $odel %vent is defined in this ork as a discrete event implemented as a 4oolean variable. " World $odel %vent represents the availability or state of  certain information generated by the World $odel. The purpose of World $odel %vent is to notify other softare modules about the state of certain predefined conditions,hich are relevant for the execution of  driving maneuvers. 1uch conditions can be, for instance, related to traffic situations e.g. 5pedestrian in front of the vehicle6, but might as ell be related to the availability of information e.g. 5721 locali8ation available6. The state of all defined World $odel %vents is provided as a k-tuple/ W$events 9,0, ...,k/ l ∈:true, false; here each element l l 9, 0, .., k represents a discrete event. The k-tuple W$events is updated cyclicly, and the World $odel notifies other  softare modules about the occurrence of certain conditions as defined for each event.

REAL TIME DECISION MAKING FOR DRIVERLESS CITY VEHICLES

'n addition to World $odel %vents, full access is provided to all data stored in the World $odel, through an ob3ect oriented data structure. This data structure contains more detailed information, such as exact distances to obstacles.#oever, a detailed discussion about the World $odel struc-ture is beyond the scope of this ork. 2.1.- In(ut 2*  The Route 2lanner/ 'n many situations, the planned route has a

significant impact on decision making.