AUTOMATED VEHICLE ROUTE PLANNER WITH ROUTE DIFFICULTY SCORING

A route-planning system suitable for use on an automated vehicle includes a memory and a controller. The memory is used to store map-data indicative of a plurality of possible-routes to a destination. Each possible-route is characterized by a difficulty-score. The controller is in communication with the memory. The controller is operable to select from the memory a preferred-route from the plurality of possible-routes. The preferred-route is selected based on the difficulty-score.

TECHNICAL FIELD OF INVENTION

This disclosure generally relates to a route-planning system, and more particularly relates to a system that selects from a plurality of possible-routes a preferred-route based on a difficulty-score of each of the possible-routes.

BACKGROUND OF INVENTION

Navigation systems that merely select a route based on shortest-distance or least-time are known. However these systems ignore many other factors that can influence the ease and/or safety of travel.

SUMMARY OF THE INVENTION

In accordance with one embodiment, a route-planning system suitable for use on an automated vehicle is provided. The system includes a memory and a controller. The memory is used to store map-data indicative of a plurality of possible-routes to a destination. Each possible-route is characterized by a difficulty-score. The controller is in communication with the memory. The controller is operable to select from the memory a preferred-route from the plurality of possible-routes. The preferred-route is selected based on the difficulty-score.

DETAILED DESCRIPTION

FIG. 1illustrates a non-limiting example of a route-planning system10, hereafter referred to as the system10, which is suitable for use on an automated-vehicle12, hereafter the vehicle12. While the description and examples presented herein are generally directed to fully-automated or autonomous vehicles, it is contemplated that the advantages of the system10described herein are applicable to partially automated vehicles where assistance is provided to an operator (not shown) of the vehicle12who is generally in control of the vehicle-controls14of the vehicle12. That is, the vehicle12may be operated in an automated-mode16(i.e. fully-automated) or a manual-mode18, or a partial blend of those two modes.

The system10includes a memory20used to store map-data22indicative of a plurality of possible-routes24to a destination26, wherein each possible-route is characterized by a difficulty-score28. While the memory20is illustrated as being within a controller30of the system10, it is contemplated that the memory20could be off-board, i.e. located ‘in-the-cloud’, and accessed by a number if known communications methods such as a WI-FI® network or cellular telephone network.

The difficulty-score28of each of the possible-routes24may be calculated or accumulated from predetermined values for each section of roadway present in the map-data22that were defined by a mapping-service. The difficulty-score28of a particular route may be an accumulation of these predetermined values or sections or roadway used to form the route. The difficulty-score28may be based on one or more roadway-characteristics72such as, but not limited to, road-width32, road-curviness34, speed-limit36, landmark-presence38, traffic-history40, lane-change-count42, roadway-marking-quality44, traffic-signal-count46, stop-sign-count48, and route-ingress-count50. That is, the difficulty-score28of each of the possible-routes24may be a summation of the predetermined values for each of the sections of roadway that will be traveled if the vehicle12travels a particular route.

The accumulation or summation process may have different weightings applied to the roadway-characteristics72for different vehicles. For example, a large-truck may use a greater weighting than a sports-car for the road-width32or the road-curviness34. Alternatively, a single instance of one of the roadway-characteristics72being greater than some threshold value may be sufficient for the vehicle12to not select one of the possible-routes24as the preferred-route52.

The predetermined values may be updated as, for example, the roadway-marking-quality44deteriorates due to age, or the road-width32changes as the result of a construction project. The updates may be based on, for example, images sent from cameras on vehicles that previously traveled a particular section of roadway, and on other more dynamic conditions such as weather which will be described in more detail below.

The controller30is in communication with the memory20. The controller30is operable (i.e. programmed) to select from the memory20a preferred-route52from the plurality of possible-routes24. The preferred-route52is generally selected based on the difficulty-score28of each of the possible-routes24. By way of example and not limitation, the difficulty-score28of the preferred-route52may be characterized as the possible-route that has the minimum difficulty-score or a minimum-score54of the possible-routes24. However, it is recognized that simply selecting the preferred-route52based on which of the possible-routes has the minimum-score54may lead to, for example, unnecessarily long travel-times to the destination26.

Alternatively, the difficulty-score28of the preferred-route52may be selected based on the criteria that the difficulty-score28is at least less than a difficulty-threshold56, which may be predetermined by the mapping service, determined by the type of the vehicle12(e.g. large-truck vs. sports-car), or selected by an operator of the vehicle12. That is, the preferred-route52may not necessary be the absolutely easiest route to drive, for example, but it is sufficiently easy. In addition to having a sufficiently low value of the difficulty-score28, the preferred-route52may be further selected based on which of the possible-routes24has or is characterized as a shortest-route58based on a comparison of indicated travel distances, a quickest-route60based on a comparison of projected travel times, and/or a least-fuel-route62based on an estimate of how much fuel will be consumed by traveling each of the possible-routes24.

While having a predetermined value of the difficulty-score28for each of the possible-routes24may be advantageous for reasons of convenience and/or consistency, it is contemplated that those baseline values of the difficulty-score28may be advantageously modified using score-modifiers64to take into account a variety of special situations or conditions. For example, the difficulty-score28of each of the possible-routes24may be modified based on one or more of traffic-density66as reported by a traffic information service, weather-conditions68as reported by a weather report service, and vehicle-capability70as indicated by the general design of the vehicle12. For example, the baseline values of the difficulty-score28may be used if the weather report indicates that the roads are dry. However, if one or more of the sections of roadways that form a particular route are snow-covered, the difficulty-score28for that particular route may be increased, possibly to a value greater than the difficulty-threshold56. For example, a twisty mountain pass may have an acceptable value of the difficulty-score28less than the difficulty-threshold56when dry, but greater than the difficulty-threshold56when snow covered. As another example, a short up-hill merge ramp from a stop-sign onto an express-way may be acceptable for a typical automobile, but too difficult for a heavy truck, so the heavy truck may look for an alternative route.

FIG. 2illustrates a non-limiting example of a plurality of possible-routes24from a present-location74to a destination26. Route A uses a secondary, typically a two-lane road, through a mountain-range76that is relatively narrow, twisty, and includes substantive elevation changes. Route B also uses a secondary type road, but is less twisty with fewer elevation changes when compared to route A. Route C uses a divided highway or express-way for most of the trip to the destination26. If the roads are dry and the vehicle12is capable (e.g. a typical automobile), then route A may be selected as the preferred-route52because it quicker, i.e. has the least travel-time. If route A is snow-covered, then route B may be selected as the preferred-route for an automobile because route B is still quicker and more fuel efficient that route C. However, if the vehicle12is a large truck, route C may be the preferred-route52because a slow-moving truck may impede the travel of other vehicles if the large truck uses route A or route B.

Referring back toFIG. 1, the system10may include a plurality of sensors80used to detect or determine the presence of an object82or gather information about the roadway being traveled. The plurality of sensors80may include, but is not limited to, a camera, a radar-unit, a lidar-unit, or any combination thereof that may be useful to detect, determine a location of, and/or identify the object82. The plurality of sensors80may also include a transceiver used for vehicle-to-infrastructure (V2I) communications, vehicle-to-vehicle (V2V) communications, or vehicle-to-pedestrian (V2P) communications, which are sometimes generically labeled V2X communications. The difficulty-score28of each of the possible-routes24may be modified based on functional-status84of each sensor. For example, the preferred-route52may be selected to avoid high-speed roads if the long-range detection capability of the radar-unit is not functional. As another example, the preferred-route52may be selected to avoid routes with numerous traffic-lights if transceiver that provides for V2I communication has failed.

It is also contemplated that the vehicle-capability70may change over time, i.e. the software that operates the vehicle12may ‘learn’ the vehicle-capability70. For example, when a car's first delivered, the driving algorithm installed in the vehicle12may not be mature enough for it to handle some sharp turns. So the system10will avoid those turns. Eventually, through self-learning, the algorithm is upgraded or tuned so the vehicle12can handle those sharp turns. That is, the navigation system may modify the computing of the difficulty-score28so that the vehicle12can select a route with sharp turns in it that it would have initially avoided.

Accordingly, a route-planning system (the system10), a controller30for the system10and a method of operating the system10is provided. The system is an improvement over prior navigation systems that merely select a route based on shortest-distance or least-time because the system10takes into consideration the roadway-characteristics72of the possible-routes24which are relatively fixed, and takes into consideration dynamic conditions (the score-modifiers64) such as weather.