MODEL BASED METHOD TO ASSESS ROAD CURVATURE EFFECT ON TRAVEL TIME AND COMFORT FOR ROUTE PLANNING

• US 20110046877A1
• Filed: 08/20/2009
• Published: 02/24/2011
• Est. Priority Date: 08/18/2009
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Hoffmann, Gabriel M.
• Granted Patent: US 8,306,732 B2
• Time in Patent Office: Days
• US Class Current: 701/206
• CPC Class Codes: G01C 21/3461 Preferred or disfavoured areas, e.g. dangerous zones, toll or emission zones, intersections, manoeuvre types, segments such as motorways, toll roads, ferries
• CPC Class Codes: G01C 21/3492 employing speed data or traffic data, e.g. real-time or historical traffic control systems for road vehicles involving transmission of navigation instructions to the vehicle G08G1/0968

Abstract

Methods and systems for assessing the effect of road curvature on the travel time and the comfort level of a path determined by a ground based route planning system. The methods and systems identify a path and determine an allowable speed profile of the path, wherein the allowable speed profile satisfies a cross track acceleration constraint. Thereafter, the methods and systems determine an optimal speed profile of the path, wherein the optimal speed profile satisfies both an along track acceleration constraint and a speed constraint. Using the optimal speed profile, the road curvature of a path may be factored into a determination of the traversal time of the path. Additionally, using the optimal speed profile, the road curvature of a path may be used to derive a comfort level of the path and/or to provide driver assistance.

Claims

1. A method for assessing road curvature of a path, including a plurality of waypoints, said method comprising the steps of:

a) determining an allowable speed profile of the path, wherein said allowable speed profile includes an allowable speed for the each of the plurality of waypoints, wherein the allowable speed for the each of the plurality of waypoints satisfies a cross track acceleration constraint; and

,

b) determining an optimal speed profile of the path, wherein said optimal speed profile includes an optimal speed for the each of the plurality of waypoints, wherein the optimal speed for the each of the plurality of waypoints satisfies both an along track acceleration constraint and a speed constraint, wherein said speed constraint is a minimum of the desired speed and the allowable speed.

2. The method of claim 1, wherein the path is a space-indexed path.

3. The method of claim 1, wherein the desired speed of the each of the plurality of waypoints is a driving speed limit.

4. The method of claim 1, wherein the allowable speed profile is determined using an approximate path curvature of the path.

5. The method of claim 1, wherein determining the optimal speed profile includes:

sweeping through the plurality of waypoints in a first direction to determine an along track acceleration profile, wherein the along track acceleration profile satisfies a negative acceleration constraint; and

,

sweeping through the plurality of waypoints in a second direction to update the along track acceleration profile, wherein the updated along track acceleration profile satisfies both a negative acceleration constraint and a positive acceleration constraint.

6. The method of claim 1, further comprising determining an optimal travel time of the path based upon the optimal speed profile.

7. The method of claim 1, further comprising determining a comfort level of the path based upon a frequency response of the path.

8. The method of claim 7, wherein the frequency response of the path is based upon real time driving data.

9. The method of claim 7, wherein the frequency response of the path is based upon the optimal speed profile.

10. The method of claim 1, wherein the optimal speed profile is determined simultaneously with the path.

11. A system for assessing road curvature in response to requests from one or more users, said system comprising:

an interface operative to communicate with the one or more users, wherein the interface receives the requests from the one or more users;

a path generator operative to generate a first path between a first point and a second point in response to a path request, wherein the first path includes a plurality of waypoints;

a road curvature assessor operative to generate an optimal speed profile for a second path in response to an assessment request, wherein the optimal speed profile for the second path satisfies both acceleration constraints and speed constraints; and

,

a controller operative to respond to each of the requests via the interface, wherein said controller selectively relays the requests to the path generator and/or the road curvature assessor, wherein said controller selectively relays paths from the path generator to the road curvature assessor.

12. The system of claim 11, wherein the road curvature assessor includes an allowable speed module adapted to determine an allowable speed profile of the second path and an optimal speed module adapted to determine the optimal speed profile of the second path, wherein the optimal speed profile is dependent upon the allowable speed profile.

13. The system of claim 11, wherein the interface communicates with the one or more users via a communications network.

14. The system of claim 11, wherein the interface communicates with the one or more users via a user input device.

15. The system of claim 11, wherein the acceleration constraints include a cross track acceleration constraint and an along track acceleration constraint.

16. The system of claim 11, wherein the acceleration constraints are selectable by the one or more users.

17. The system of claim 11, wherein the controller controls a speed regulator of an automobile based upon the optimal speed profile and a current position input.

18. The system of claim 11, wherein the controller provides an optimal travel time of a third path corresponding to a request, wherein the optimal travel time is based upon an optimal speed profile corresponding to the third path.

19. The system of claim 11, wherein the controller provides a comfort level of a fourth path corresponding to a request, wherein the comfort level is based upon a frequency response of the fourth path corresponding to the request.

20. A system for assessing road curvature of a path, wherein said path includes a plurality of waypoints, wherein each of said plurality of waypoints includes a desired speed, said system comprising:

an allowable speed module adapted to determine an allowable speed profile of the path, wherein said allowable speed profile includes an allowable speed for the each of the plurality of waypoints, wherein the allowable speed for the each of the plurality of waypoints satisfies a cross track acceleration constraint; and

,

an optimal speed module adapted to determine an optimal speed profile of the path, wherein said optimal speed profile includes an optimal speed for the each of the plurality of waypoints, wherein the optimal speed for the each of the plurality of waypoints satisfies both an along track acceleration constraint and a speed constraint, wherein said speed constraint is a minimum of the desired speed and the allowable speed.