Method for providing a collision free path in a three-dimensional space
First Claim
1. A method for collision free navigation in a predefined region comprising:
- storing a predetermined set of points defining the available paths through navigable free space in the region, each of the points having associated therewith predetermined navigational constraints;
receiving externally generated position coordinates;
receiving externally generated navigational limitations;
comparing the received navigational limitations with the navigational constraints associated with the stored predetermined set of points to determine the ones of a predetermined set of points that can be safely navigated;
generating a collision free set of points that is comprised of the ones of the predetermined set of points that can be safely navigated through the free space in the region;
calculating the shortest path through the collison free set of points that can be navigated from the received position coordinates to a predetermined goal; and
outputting coordinates defining the calculated shortest path.
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Abstract
A method for providing a collision free safe path includes storing predetermined spatial graphs representing the set of points defining the collision free paths within that region and calculating the shortest path over the region. Each of the points in the graph have associated therewith predetermined constraints which, where compared to real world navigational limitations, determine if the path is navigable. A collision free path is generated by first examining the set of points defining the path and comparing them with the real world limitations. If all of the available paths are not collision free on the prestored spatial graph, a modified spatial graph, at a different altitude if necessary, is defined with collision free paths and then the shortest path between two points on this graph determined and output to a navigation system. In the event that the initial navigational limitations are altered during traversing of the shortest path, the same process will be repeated, i.e., a new spatial graph can be generated defining the collision free paths and the shortest path determined along this new shortest path from the point at which the navigational limitations changed.
123 Citations
29 Claims
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1. A method for collision free navigation in a predefined region comprising:
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storing a predetermined set of points defining the available paths through navigable free space in the region, each of the points having associated therewith predetermined navigational constraints; receiving externally generated position coordinates; receiving externally generated navigational limitations; comparing the received navigational limitations with the navigational constraints associated with the stored predetermined set of points to determine the ones of a predetermined set of points that can be safely navigated; generating a collision free set of points that is comprised of the ones of the predetermined set of points that can be safely navigated through the free space in the region; calculating the shortest path through the collison free set of points that can be navigated from the received position coordinates to a predetermined goal; and outputting coordinates defining the calculated shortest path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for providing a collision free path to a navigation system to allow collision free navigation through navigable free space in a three-dimensional space, comprising:
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storing a plurality of predetermined spacial graphs each associated with a two-dimensional level in the three-dimensional space, each of the predetermined spacial graphs representing all available discrete paths through the associated two-dimensional level with all available paths interconnected and each path having associated therewith predetermined navigational constraints; receiving externally generated position coordinates to define the present position of the navigation system in the three-dimensional space; receiving externally generated navigational limitations from the navigation system; comparing the received navigational limitations with the predetermined navigational constraints for each of the available paths on each of the levels to determine for each of the levels ones on the available paths that can be safely navigated; generating a collision-free spacial graph for each two-dimensional level, each collision free spacial graph comprised of the available safe paths of the corresponding predetermined spacial graph that can be safely navigated collision free; calculating the shortest path along the collision free available paths between the present position and a predetermined goal and in accordance with a predetermined shortest path algorithim; and outputting coordinates defining the calculated shortest path to the navigation system. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for providing a collision free path for a navigation system to allow collision free navigation through navigable free space between obstacles in a three-dimensional space, comprising:
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storing a plurality of predetermined spacial graphs each associated with a two-dimensional level in the three-dimensional space, each of the spacial graphs representing all available discrete paths through the free space in the associated two-dimensional level with all available paths interconnected and each path having associated therewith proximity information defining the proximity of the path to the obstacle closest thereto; receiving externally generated position coordinates to define the position of the navigational system in the three-dimensional space; receiving externally generated uncertainty information from the navigation system as to location; determining the maximum proximity of a path that can be navigated collision free within the constraints of the received location uncertainty; selecting the lowest level spacial graph having a path with a proximity that allows collision free navigation in accordance with the location uncertainty constraints, the spacial graphs arranged in an ascending order from the lowest level to the highest level; generating a collision free spacial graph comprised of paths of the selected predetermined spacial graphs that can be safely navigated collision free in accordance with the location uncertainty constraints; calculating the shortest path along the collision free available paths between the present position and a predetermined goal and in accordance with a predetermined shortest path algorithm; and outputting coordinates defining the calculated shortest path to the navigation system. - View Dependent Claims (21, 22, 23)
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24. A method for providing a collision free path for a navigation system to allow collision free navigation between obstacles in a three-dimensional space, comprising:
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storing a plurality of predetermined spacial graphs each associated with a two-dimensional level in the three-dimensional space, each of the predetermined spacial graphs representing all available discrete paths through the associated two-dimensional level between known obstacles; receiving externally generated coordinates of an unexpected obstacle when the unexpected obstacle is detected; receiving externally generated position coordinates to define the present position of the navigation system in the three-dimensional space when the unexpected obstacle is detected; modifying the predetermined spacial graphs to remove any of the available paths in any of the two-dimensional levels that are blocked by the obstacle; determining the shortest collision free straight line path from the point of detection of the unexpected obstacle to the closest point on the modified spacial graph in accordance with predetermined motion constraints to define a new starting coordinate; selecting the lowest level of the modified spacial graphs having an available path between the new starting coordinates and a predetermined goal; calculating the shortest path along the available path in the selected level between the new starting coordinates and the predetermined goal and in accordance with a shortest path algorithm; outputting the coordinates of the calculated shortest path through the navigational system. - View Dependent Claims (25, 26, 27, 28, 29)
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Specification