Method and system for guiding a vehicle
Movement of a vehicle such as a boat ( 30 ) is guided by dynamically monitoring parameters and generating instructions for the operator. The instructions are at a level to attain a number of sub-goals to reach a goal position ( 33 ) from a current position ( 32 ). Each sub-goal is attained in a single vehicle manoeuvre such as straight-ahead or rotation, each manoeuvre being instructable to the operator. The instructions are generated using a space model ( 12 ) of the space around the vehicle, an operator model ( 11 ) of operator vehicle control characteristics, and a vehicle model ( 12 ) of vehicle movement characteristics.
1. A vehicle guidance system ( 1 ) comprising means for detecting position of a vehicle ( 30 ) and a processor ( 2 ) for generating operator instructions to assist the operator to manoeuvre the vehicle, characterised in that
the system comprises range sensors ( 3 - 7 ) and means for using outputs of the sensors to dynamically maintain a space map ( 12 ) in real time;
the system comprises an operator model of operator capabilities; and
the processor ( 2 ) comprises means for planning a path to a goal position ( 33 ) in a confined space using data from the operator model ( 11 ) of operator capabilities and data from the space map ( 12 ).
2. A vehicle guidance system as claimed in claim 1 , wherein the system comprises means for maintaining the space map ( 12 ) as a set of polygons each defining a spatial area.
3. A vehicle guidance system as claimed in claim 2 , wherein said space map ( 12 ) maintaining means comprises means for processing three-dimensional space data from the sensors and for breaking said data to two-dimensional space data in a polygon framework.
4. A vehicle guidance system as claimed in claim 2 , wherein said space map maintaining means comprises means for maintaining a flag for each polygon, said flag indicating if the polygon is occupied by an object.
5. A vehicle guidance system as claimed in claim 1 , wherein the operator model ( 11 ) comprises time parameter values for the operator to perceive information, for the operator to cognitively process information, and for neuromuscular delay for implementing an action.
6. A vehicle guidance system as claimed in claim 5 , wherein the operator model ( 11 ) comprises a parameter value for spatial error for performing an action.
7. A vehicle guidance system as claimed in claim 1 , wherein the processor comprises means for storing a vehicle model ( 10 ) of movement characteristics of the vehicle ( 30 ).
8. A vehicle guidance system as claimed in claim 1 , wherein the processor ( 2 ) comprises path planning means for planning ( 24 ) a plurality of sub-goals forming a path to the goal position ( 33 ).
9. A vehicle guidance system as claimed in claim 8 , wherein the path planning means comprises means for determining a sub-goal only if it can be achieved with a single manoeuvre of the vehicle ( 30 ) and if it is instructable to the operator.
10. A vehicle guidance system as claimed in claim 8 , wherein the path planning means comprises means for determining ( 47 ) a set of candidate trajectories for reaching the goal position ( 33 ) with collision avoidance, and for performing backchaining to break each candidate trajectory into a plurality of sub-goals starting from the goal position ( 33 ) and extending back to the current position ( 32 ).
11. A vehicle guidance system as claimed in claim 10 , wherein the set of candidate trajectories is determined by generating ( 47 ) a first set of candidate trajectories compatible with the space and the vehicle models ( 10 , 12 ), and for subsequently reducing ( 48 ) the first set to those compatible with the operator model ( 11 ).
12. A vehicle guidance system as claimed in claim 10 , wherein the path planning means comprises means for dynamically repeating path planning ( 24 ) in real time at each of a plurality of vehicle positions.
13. A vehicle guidance system as claimed in claim 1 , wherein the vehicle model ( 10 ) is for a boat, and the sensors comprise a sonar device ( 3 ), a laser range finder ( 4 ), a vision system ( 5 ), a radar system ( 6 ), and a GPS circuit ( 7 ).
14. A vehicle comprising a guidance system as claimed in claim 1 .
15. A method of guiding a vehicle from a current position ( 32 ) to a goal position ( 33 ) in a confined space, the method comprising the steps of:
range sensors ( 3 - 7 ) automatically sensing objects around the vehicle ( 30 ),
a processor using outputs of the range sensors to dynamically maintain a space map ( 12 ) in real time,
the processor planning a path to the goal position ( 33 ) using data from the space map ( 12 ) and from an operator model of operator capabilities,
an output interface ( 16 - 19 ) outputting instructions to the operator for movement of the vehicle according to the planned path, and
the operator moving the vehicle according to the instructions.
16. A method as claimed in claim 15 , wherein the processor generates instructions for the operator for movement of the vehicle in a single manoeuvre at a time.
17. A method as claimed in claim 15 , wherein the processor performs backchaining to break down a path into a plurality of sub-goals, and generates an operator instruction to achieve each sub-goal in turn.
18. A method as claimed in claim 17 , wherein the processor repeats path planning at each position on the basis of the current position.
19. A method as claimed in any of claim 15 , wherein the processor generates the operator instructions also using data from a vehicle model of vehicle movement characteristics.