DETAILED MAP FORMAT FOR AUTONOMOUS DRIVING
A computer-readable detailed map format is disclosed. The detailed map format includes a plurality of lane segments and a plurality of lane links. Each of the lane links can extend between two lane segments across a traffic intersection. Each of the lane links can also be associated with one of a plurality of traffic signals. A transition rule is associated with a first lane link and based on information associated with the one of the plurality of traffic signals associated with the first lane link. An interlock rule can be based on information associated with the one of the plurality of traffic signals associated with a second lane link. The first lane link and second lane link can be associated with different traffic signals and can extend between different lane segments across the traffic intersection.
This application is a continuation-in-part of U.S. application Ser. No. 14/265,370, filed Apr. 30, 2014, which is hereby incorporated by reference in its entirety.
BACKGROUNDFully or highly automated, e.g. autonomous or self-driven, driving systems are designed to operate a vehicle on the road either without or with low levels of driver interaction or other external controls. Autonomous driving systems require certainty in the position of and distance to geographic features surrounding the vehicle with a sufficient degree of accuracy to adequately control the vehicle. Details about the road or other geographic features surrounding the vehicle can be recorded on a detailed virtual map. The more accurate the detailed virtual map, the better the performance of the autonomous driving system. Existing virtual maps do not include sufficient or sufficiently accurate geographic feature details for optimized autonomous operation.
Autonomous driving systems can also be programmed to follow transition rules, or traffic operation rules, associated with a traffic intersection when localized to (exactly positioned in respect to) the traffic intersection. Though an autonomous driving system can recognize and implement some transition rules by observing traffic signals along the a navigation route of the autonomous vehicle, information related to additional traffic signals and the associated actions of other vehicles within the traffic intersection can improve the performance of the autonomous driving system.
SUMMARYThe detailed map format described here can improve operation of a highly-automated or autonomous vehicle at traffic intersections by improving both localization (exact positioning) and control over the vehicle. The detailed map format can include lane segments associated with branches of a traffic intersection and lane links that indicate the transition path between the lane segments across the traffic intersection. Each of the lane links can be associated with transition rules governing the action of the autonomous vehicle based on the state of detected traffic signals. Each of the transition rules can be further associated with interlock rules that provide assumptions regarding the actions of other vehicles through the traffic intersection as based on the state of traffic signals that are not directly detected by the autonomous vehicle.
In one implementation, a computer-readable map format is disclosed. The map format includes a plurality of lane segments, each lane segment associated with a branch of a traffic intersection; a plurality of lane links, each lane link associated with two of the plurality of lane segments and extending between two of the branches of the traffic intersection; a plurality of traffic signals, each traffic signal associated with at least one of the plurality of lane links; a transition rule associated with a first lane link, wherein the transition rule is based on information associated with the one of the plurality of traffic signals associated with the first lane link; and an interlock rule based on information associated with the one of the plurality of traffic signals associated with a second lane link.
In another implementation, a computer-readable map format is disclosed. The map format includes a plurality of lane segments; a plurality of lane links, each lane link extending between two lane segments across a traffic intersection and associated with one of a plurality of traffic signals; a transition rule associated with a first lane link, wherein the transition rule is based on information associated with the one of the plurality of traffic signals associated with the first lane link; and an interlock rule based on information associated with the one of the plurality of traffic signals associated with a second lane link.
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
A computer-readable, highly detailed map format for an autonomous vehicle is disclosed. The detailed map format includes information representing the geographical location, travel direction, and speed limit of lanes on a road using lane segments formed of waypoints. Beyond this basic information, the detailed map format also includes lane links that represent transitions between lane segments across traffic intersections, transition rules based on the state of detected traffic signals that govern the actions of the autonomous vehicle across lane links, and interlock rules based on the inferred state of undetected traffic signals that would govern the actions of other vehicles across different lane links. The use of lane links, transition rules, and interlock rules within a detailed map formant can greatly improve the performance of an autonomous driving system.
The memory 104 can also include an operating system 110 and installed applications 112, the installed applications 112 including programs that permit the CPU 102 to perform automated driving methods using the detailed map format described below. The computing device 100 can also include secondary, additional, or external storage 114, for example, a memory card, flash drive, or any other form of computer readable medium. The installed applications 112 can be stored in whole or in part in the external storage 114 and loaded into the memory 104 as needed for processing.
The computing device 100 can also be in communication with one or more sensors 116. The sensors 116 can capture data and/or signals for processing by an inertial measurement unit (IMU), a dead-reckoning system, a global navigation satellite system (GNSS), a light detection and ranging (LIDAR) system, a radar system, a sonar system, an image-based sensor system, or any other type of system capable of capturing information specific to the environment surrounding a vehicle for use in creating a detailed map format as described below, including information specific to objects such as features of the route being travelled by the vehicle or other localized position data and/or signals and outputting corresponding data and/or signals to the CPU 102.
In the examples described below, the sensors 116 can capture, at least, signals for a GNSS or other system that determines vehicle position and velocity and data for a LIDAR system or other system that measures vehicle distance from lane lines (e.g., route surface markings or route boundaries), obstacles, objects, or other environmental features including traffic lights and road signs. The computing device 100 can also be in communication with one or more vehicle systems 118, such as vehicle braking systems, vehicle propulsions systems, etc. The vehicle systems 118 can also be in communication with the sensors 116, the sensors 116 being configured to capture data indicative of performance of the vehicle systems 118.
The vehicle 200 can also include a plurality of sensors, such as the sensors 116 described in reference to
Map formats can be constructed using geographic features captured by the vehicle 200 such as lane lines and curbs proximate the vehicle 200 as it travels a route. These geographic features can be captured using the above described LIDAR system and/or cameras in combination with an algorithm such as random sample consensus (RANSAC) to find lines, record the position of the vehicle 200, and collect data on position from a GNSS and/or an IMU. The captured geographic features can then be manipulated using a simultaneous localization and mapping (SLAM) technique to position all of the geographic features in relation to the vehicle's 200 position. Some of the geographic features can be categorized as lane borders, and lane centers can be determined based on the lane borders. Alternatively, map formats can be constructed using overhead images (e.g. satellite images) of geographic features traced by a map editor that allows selection of different categories for each geographic feature.
For example, the lane segment 308 extends from the waypoint 328 away from the intersection and the lane segment 310 extends to the waypoint 330 toward the intersection. Information can be associated with the waypoints 328, 330, 332, 334, 336, 338, 340, 342, 344, 346 and stored as part of the map format. For example, each waypoint 328, 330, 332, 334, 336, 338, 340, 342, 344, 346 can include information such as geographical location, lane speed, and lane direction. The map information associated with the lanes and intersection can be stored, for example, in the form of spline points or as curves with knot vectors in the memory 104 of the computing device 100 or can be available from a remote location.
In the example map format shown in
Additional detail can be added to the map format in order to improve the map format for use with the autonomous vehicle 200. As shown in
In addition to the lane links 348, 350, 352, 354, 356, 357, 358, 360, 362, 364, 366, 368, a plurality of traffic signals can be included in the map format. Each of the traffic signals can be associated with at least one of the lane links 348, 350, 352, 354, 356, 357, 358, 360, 362, 364, 366, 368 and information associated with the traffic signals can include a geographical location, a traffic signal type, and a traffic signal state. Traffic signal type can include information on the structure and orientation of a traffic light or traffic sign. Traffic signal structure and orientation for a traffic light can include “vertical three,” “vertical three left arrow,” “horizontal three,” “right arrow,” etc. Traffic signal state for a traffic light can include, for example, “green,” “green arrow,” “yellow,” “blinking yellow,” or “red.”
In
Similarly, the traffic light 378 can be associated with the lane link 352 and displayed as such using the same pattern in the map format. The lane link 352 is understood to indicate a left turn from the lane segment 316 to the lane segment 308. Both of the traffic lights 376, 378 directing traffic exiting branch 302 of the traffic intersection can have the same structure, orientation, and state at the same time. In one more example, the traffic light 382 can be associated with the lane link 354, where the lane link 354 represents a right turn from the lane segment 322 to the lane segment 324.
As described in
This transition rule of “go” is represented within the map format using a first line type, a dashed line, in association with the lane links 348, 350. The “green” state of the traffic light 376 is also shown with a specific line type, in this case, a solid line, and can, for example, be detected by one or more of the sensors 116 disposed on the autonomous vehicle 200 when the autonomous vehicle 200 is located on lane segment 316. The lane links 348, 350 and the traffic light 376 are shown in a bold style to indicate that in the example of
Though a transition rule can be based on the state of one of the traffic signals as directly detected by the autonomous vehicle 200 while navigating along a route, additional information regarding the transition of other vehicles through the traffic intersection would improve the performance of the automated driving system. Hence, the detailed map format has been improved to include interlock rules. Each interlock rule can be inferred from one of the transition rules governed by an interlocked traffic signal. An interlocked traffic signal refers to a traffic signal having a specific traffic signal state based on the traffic signal state of a different traffic signal.
For example, if the autonomous vehicle 200 is positioned along lane segment 316, the state of at least one of the traffic lights 376, 378 can be captured directly by the autonomous vehicle 200, for example, as “green.” The state of the traffic lights 372, 374 can then be inferred to be “red,” which is shown in the detailed map format using a different line style than the solid line used for the traffic lights 376, 378, since the traffic lights 372, 374 are interlocked traffic signals to the traffic lights 376, 378 given the structure of the traffic intersection. That is, if traffic is free to proceed from the branch 302 to the branch 306, traffic must not be allowed to proceed from the branch 300 to the branch 304 at the same time. Further, the transition rule “go” as associated with the lane links 348, 350 and the traffic light 376 when the state of the traffic light 376 is “green” leads to an inference of the interlock rule “stop” associated with the lane link 366 and the traffic light 374 based on the interlocked state of the traffic light 374 as “red.”
In another example, the transition rule “go” associated with the lane links 348, 350 and the traffic light 376 indicating that the autonomous vehicle 200 can proceed either straight or right through the traffic intersection when the state of the traffic light 376 is “green” can lead to the inference of the interlock rule “stop” associated with the lane link 356 and the traffic light 380 indicating that another vehicle must stop at the traffic intersection at the end of the lane segment 322 and cannot proceed through the traffic intersection to the lane segment 308 since the state of the traffic light 380 is inferred to be “red” given the state of the traffic light 376 being “green.” The interlock rule “stop” as associated with the traffic lights 374, 380 and the lane links 356, 366 and as inferred from the transition rule “go” as associated with the traffic light 376 and the lane links 348, 350 is shown in this example map format by using the same type of line to represent the lane links 356, 366, a closely spaced dotted line.
In the prior two examples, the lane links 348, 350 and the lane links 356, 366 are associated with different traffic signals, specifically, the traffic light 376 and the traffic lights 374, 380, and extend between different branches 300, 302, 304, 306 of the traffic intersection. Any number of interlock rules can be inferred from a given transition rule depending on the structure of the traffic intersection as detailed within the map format. In the example map format of
Another set of interlock rules represented in the example map format of
Though the example transition rules and interlock rules that are possible to guide vehicles through the traffic intersection based on the traffic signal types and traffic signal states described in reference to
Each of the lane segments 432, 434, 436, 438, 440, 442, 444, 446, 448, 450, 452 within the branches 402, 406 can be further associated with borders formed of one or more border segments extending between at least two borderpoints. For simplicity, only a few of the border segments and borderpoints are numbered in the example map format shown in
The additional information provided by the stop lines 466, 468 is useful in operation of the autonomous vehicle 200 because the stop lines 466, 468 allow the autonomous vehicle 200 to be positioned at the traffic intersection in a manner consistent with manual operation of a vehicle. For example, if the autonomous vehicle 200 approaches the traffic intersection along the lane segment 434, instead of stopping at the waypoint 410 denoting the end of the lane segment 434, the autonomous vehicle 200 can be controlled to move forward to the stop line 466. This maneuver is more consistent with how a driver would manually operate a vehicle, for example, to pull forward to a designated location when stopping at a traffic intersection. Though not shown, crosswalks can also be included in the detailed map format in a manner similar to that used for the stop lines 466, 468. Information associated with the crosswalks can include a geographical location of a position of the crosswalk and a driving rule associated with the crosswalk that directs the automated vehicle system to implement additional safety protocols.
Traffic signals are also included in the map format shown in
In
In addition to including transition rules associated with the lane links 477, 478, 480, 482, 484, 486, 488, 490 and based on the state of the traffic lights 470, 472, 474, 476, the map format of
The foregoing description relates to what are presently considered to be the most practical embodiments. It is to be understood, however, that the disclosure is not to be limited to these embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
Claims
1. A computer-readable map format, comprising:
- a plurality of lane segments, each lane segment associated with a branch of a traffic intersection;
- a plurality of lane links, each lane link associated with two of the plurality of lane segments and extending between two of the branches of the traffic intersection;
- a plurality of traffic signals, each traffic signal associated with at least one of the plurality of lane links;
- a transition rule associated with a first lane link, wherein the transition rule is based on information associated with the one of the plurality of traffic signals associated with the first lane link; and
- an interlock rule based on information associated with the one of the plurality of traffic signals associated with a second lane link.
2. The map format of claim 1, wherein the first lane link and the second lane link are associated with different traffic signals.
3. The map format of claim 1, wherein the first lane link and the second lane link extend between different branches of the traffic intersection.
4. The map format of claim 1, wherein the information associated with each traffic signal includes a geographical location and a traffic signal type and a traffic signal state.
5. The map format of claim 4, wherein the traffic signal type includes information regarding structure and orientation for at least one of a traffic light and a traffic sign.
6. The map format of claim 4, wherein the traffic signal type is a traffic light and the traffic signal state includes at least one of green, green arrow, yellow, blinking yellow, and red.
7. The map format of claim 4, wherein the transition rule is based on the traffic signal state of the one of the plurality of traffic signals associated with the first lane link.
8. The map format of claim 4, wherein the interlock rule is based on an inferred traffic signal state for the one of the plurality of traffic signals associated with the second lane link.
9. The map format of claim 1, further comprising:
- a stop line associated with an end of at least one of the plurality of lane segments, wherein information associated with the stop line includes a geographical location, the geographical location representing a position where a vehicle must stop before the traffic intersection.
10. The map format of claim 1, wherein the lane segment is formed from a plurality of waypoints and wherein information associated with each waypoint includes at least one of a geographical location and a lane speed and a lane direction.
11. A computer-readable map format, comprising:
- a plurality of lane segments;
- a plurality of lane links, each lane link extending between two lane segments across a traffic intersection and associated with one of a plurality of traffic signals;
- a transition rule associated with a first lane link, wherein the transition rule is based on information associated with the one of the plurality of traffic signals associated with the first lane link; and
- an interlock rule based on information associated with the one of the plurality of traffic signals associated with a second lane link.
12. The map format of claim 11, wherein the first lane link and the second lane link are associated with different traffic signals.
13. The map format of claim 11, wherein the first lane link and the second lane link extend between a different set of two lane segments across the traffic intersection.
14. The map format of claim 11, wherein the information associated with each traffic signal includes a geographical location and a traffic signal type and a traffic signal state.
15. The map format of claim 14, wherein the traffic signal type includes information regarding structure and orientation for at least one of a traffic light and a traffic sign.
16. The map format of claim 14, wherein the traffic signal type is a traffic light and the traffic signal state includes at least one of green, green arrow, yellow, blinking yellow, and red.
17. The map format of claim 14, wherein the transition rule is based on the traffic signal state of the one of the plurality of traffic signals associated with the first lane link.
18. The map format of claim 14, wherein the interlock rule is based on an inferred traffic signal state for the one of the plurality of traffic signals associated with the second lane link.
19. The map format of claim 11, further comprising:
- a stop line associated with an end of at least one of the plurality of lane segments, wherein information associated with the stop line includes a geographical location, the geographical location representing a position where a vehicle must stop before the traffic intersection.
20. The map format of claim 11, wherein the lane segment is formed from a plurality of waypoints and wherein information associated with each waypoint includes at least one of a geographical location and a lane speed and a lane direction.
Type: Application
Filed: Jun 10, 2014
Publication Date: Nov 5, 2015
Inventors: Kentaro Ichikawa (Shizuoke-prefecture), Michael J. Delp (Ann Arbor, MI)
Application Number: 14/301,079