Autonomous vehicle automatically running on route and its method

• US 5,229,941 A
• Filed: 04/13/1989
• Issued: 07/20/1993
• Est. Priority Date: 04/14/1988
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Hattori, Akira
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/337,707
• Time in Patent Office: 1,559 Days
• Field of Search: 364/424.02, 364/424.01, 364/460, 364/444, 364/449, 358/103, 340/995, 340/990, 340/988, 180/167-169, 318/587
• US Class Current: 701/26
• CPC Class Codes: G05D 1/0217 in accordance with energy consumption, time reduction or distance reduction criteria

Abstract

An autonomous vehicle autonomously running on a route of travel and its method are disclosed in which data on a plurality of target points and on a plurality of paths, the target points and paths defining start and end points of road segments which are the respective paths into which the route of travel is divided are stored into a data storage block, a shape of each road segment is determined on the basis of the stored data in the data storage block, a target running state is set on the basis of the determined shape of each road segment, and a run control of the vehicle is carried out on the basis of the set running state. In addition, a new target point on one of the paths is set which provides a shortest distance from a new point to the corresponding path and data on the new target point is provided which includes the data on the running state at the new target point so that a start point and/or a final target point at which the vehicle is finally to reach can arbitrarily set on the route of travel.

Claims

1. An autonomous vehicle comprising:

a) first means for storing information on each of a plurality of predetermined road segments, a route of travel on which the vehicle is to pass to reach a destination being divided into the plurality of predetermined road segments;

b) second means for determining a shape for each road segment on the basis of the stored information of the first means;

c) third means for setting a target running state of the vehicle for each road segment on the basis of the determined shape; and

d) fourth means for determining a current running route situation, autonomously running the vehicle on the basis of the determined running route situation, and controlling the run of the vehicle on the basis of the set running state,

wherein the first means includes;

e) fifth means for setting a plurality of target points on the route of travel, each target point defining start and end points of each road segment, and for storing information on each target point thereinto; and

f) sixth means for storing information on each path defined as each road segment from its target point to the subsequent target point, and

which further includes;

g) seventh means for setting a new target point on one of the paths, the new target point providing a shortest distance from a first point on a route of travel other than the route of travel corresponding to the one path; and

h) eighth means for providing information on the newly set target point by the seventh means, the information thereon including the information on a running situation representing a distance of the vehicle from a guide line and an orientation of the vehicle with respect to the guide line at the new target point.

2. An autonomous vehicle as set forth in claim 1, wherein the seventh means includes:

ninth means for setting a present point S of the vehicle at which the vehicle is started to run and a final target point E to which the vehicle is finally to reach, each position of the start point S and final target point E defining the first point;

tenth means for determining a new first path on one of the paths from the start point S to a first new target point, the new first path being present in the shortest distance from the start point S, eleventh means for determining a new second path on one of the paths from the final target point E to a second new target point, the new second path being present in the shortest distance from the final target point;

twelfth means for setting the first and second new target points on the corresponding first and second new paths; and

thirteenth means for erasing the information on the paths on which the first and second new paths are superposed and updating the information thereof according to the first and second new paths.

3. An autonomous vehicle as set forth in claim 2, wherein the present point S and final target point E are expressed and inputted as (x_s, y_s, θ

_s) and (x_e, y_e, θ

_e), wherein x and y denote coordinates in a global coordinate system with a position of an origin at which the vehicle is to start and θ

denotes an angle of a global posture of the vehicle in the forward direction of the vehicle (-180 degrees≦

θ

≦

+180 degrees).

4. An autonomous vehicle as set forth in claim 3, wherein said tenth means determines the new first path by drawing a perpendicular from the start point S to each path or drawing a straight line from the start point S to each target point at which the corresponding path is started in a case where each path as each road segment is constituted by a straight road segment, or by drawing a normal from the start point to each path or drawing a straight line from the start point S to each target point at which the corresponding path is ended in a case where each path as each road segment is constituted by a curved road segment, by deriving each distance from the start point S to a point at which the perpendicular, straight line, or normal is intersected with each path, and by deriving the shortest of the derived distances, one of the points at which the perpendicular, straight line, or normal is intersected which provides the shortest distance from the start point S being determined to be the new first target point.

5. An autonomous vehicle as set forth in claim 4, wherein the eleventh means determines the new second path by drawing a perpendicular from the final target point E to each path or drawing a straight line from the final target point E to each target point at which the corresponding path is started in a case where each path as each road segment is constituted by a straight road segment, or by drawing a normal from the final target point E to each path or drawing a straight line from the final target point E to each target point at which the corresponding path is ended in a case where each path as each road segment is constituted by a curved road segment, by deriving each distance from the final target point E to a point at which the perpendicular, straight line, or normal is intersected with each path, and by deriving the shortest of the derived distances, one of the points at which the perpendicular, straight line, or normal is intersected which provides the shortest distance from the final target point E being determined to be the new second target point.

6. An autonomous vehicle as set forth in claim 5, wherein the eighth means derives a first angle formed between a tangential line passing through the new first target point and a straight line passing through the start point and in parallel to the elongated direction of the vehicle, a second angle formed between a tangential line passing through the new second target point and a straight line passing through the final target point and in parallel to the elongated direction of the vehicle, and searches the information of the paths stored in the sixth means for the plurality of paths from the start point S to the final target point E, the plurality of paths constituting the route of travel to the final target point which provides the shortest distance from the start pont S to the final target point E.

7. An autonomous vehicle comprising:

a) first means for storing information on each of a plurality of predetermined road segments, a route of travel on which the vehicle is to pass to reach a destination being divided into the plurality of predetermined road segments;

b) second means for determining a shape for each road segment on the basis of the stored information of the first means;

c) third means for setting a target running state of the vehicle for each road segment on the basis of the determined shape; and

d) fourth means for determining a current running route situation, autonomously running the vehicle on the basis of the determined running route situation, and controlling the run of the vehicle on the basis of the set running state,

wherein the first means includes;

e) fifth means for setting a plurality of target points on the route of travel, each targe point defining start and end points of each road segment, and for storing information on each target point thereinto; and

f) sixth means for storing information on each path defined as each road segment from its target point to the subsequent target point, and

wherein the information of each target point stored in the fifth means includes x and y coordinates of each target point representing an absolute position of each target point on a road map and a name of each target point and the information of each path stored in the sixth means includes a radius of curvature of each path, a length of each path, an angle formed between a tangential line of each target point on the corresponding path and geomagnetic East direction, a road width of each path, the number of traffic lanes on each path, a shape of a start target point of each path, and a shape of an end target point on each path, and classification of one-way traffic or two-way traffic of each path.

8. An autonomous vehicle as set forth in claim 7, wherein the second means determines the shape for each road segment on the basis of the information of each target point and each path stored in the fifth and sixth means.

9. An autonomous vehicle as set forth in claim 8, wherein the third means includes a first sensing unit for detecting and locally deriving a relative position of the vehicle to an object to be sensed present in an end of each road segment and includes seventh means for sequentially producing and outputting a run command PR(j) and a target point command PO(i) on the basis of the information on each target point and each path stored in the fifth and sixth means, said seventh means outputting the target point command PO(i) (i=0, 1, 2, - - - , n max) and the run command PR(j) (j=1, 2, - - - , o max) to the fourth means in paired couples wherein i=j, and wherein the fourth means controls running of the vehicle through a vehicular component including a power driving source, a power transmission, and brake mechanism of the vehicle in response to each of the coupled run commands and target point commands issued from the seventh means.

10. An autonomous vehicle as set forth in claim 9, wherein each run command PR(j) includes information identifying a target point command to be paired therewith, a distance of a road center line between a corresponding target point and subsequent target point, a target vehicle speed during the run on each path, a target steering angle at each target point, a selection of a white line to be sensed by the first sensing unit, a distance of the vehicle to the white line to be maintained by the vehicle, and a local target vehicle posture and each target point command PO(i) includes items of a global target position of the vehicle at each target point in the absolute coordinate system (x_g, y_g, 0), a local target position of the vehicle at each target point (x_l, x_r, 0_d), a target vehicle speed V_po at each target point, and a target steering angle S_po at each target point.

11. An autonomous vehicle as set forth in claim 10, wherein the third means previously sets ten kinds of command rules according to the shape determined by the second means, a first rule being such that one of the target point commands PO(i+1) is set at the same point as the target point N, the target vehicle speed V_po thereof being set to a relatively lower speed and the target steering angle S_po being set at a constant angle, so that the fourth means controls the run of the vehicle so that the vehicle is gradually steered, decreasing the speed at a position of the corresponding target point through which the vehicle enters a curved road segment, a second rule being such that one of the target point commands PO(i+1) is set at a position in a forward direction with respect to the point of the corresponding target point N, at that position, the target vehicle speed V_po being set at a relatively high speed and the target steering angle S_po being set to zero, and one of the run command PR(j+1) is set in which the run target vehicle speed V_pr is set to a relatively low speed, the run target steering angle S_pr is set at a constant angle, and by selection of Q_o is set to right or left, so that the fourth means accelerates the vehicle at a last half of a curved road segment, gradually returning the vehicle steering angle to an original angle, a third rule being such that one of the target point commands PO (i) is set at a position in front of the corresponding target point N and thereby a lane distance d in the coupled run command PR(j+1) is corrected, a fourth rule being such that one of the target point commands PO(i+1) is set at a position before the corresponding target point N which is a branching point, the target vehicle speed V_po being set to a relatively low speed and target steering angle being set to a constant angle, so that the fourth means gradually steers the vehicle, decreasing the vehicle speed at the position before the vehicle enters the branching point, a fifth rule being such that one of the target point command PO(i+1) is set at a position in the forward direction with respect to the target point N which is the branching point, the target vehicle speed V_po of the target point command PO(i+1) being set at a relatively high speed, the target steering angle S_po being set to zero, the target vehicle speed V_pr of the run command PR(j+1) being set to a relatively low speed, and the target steering angle S_pr being set to a constant angle, so that the fourth means accelerates the vehicle after the passage of the branching point, gradually returning the steering angle to an original angle, a sixth rule being such that one of the target point commands PO(i) is set at a position in the forward direction with respect to the target point N and the lane distance d in the run command PR(j+1) is corrected, a seventh rule being such that one of the target point commands PO (i+1) is set at a position before the target point N which is the intersection, the target vehicle speed V_po of the target point command PO (i+1) being set at a relatively low speed, so that the fourth means decreases the vehicle speed at the position before the intersection, an eighth rule being such that one of the target point commands PO(i) is set at a position in the forward direction with respect to the corresponding target point N which is the intersection, the target vehicle speed V_po of the target point command PO(i+1) being set to a relatively high speed, the run target vehicle speed of the run command PR (j+1) being set to a relatively low speed, the selection Q_o thereof being set to "nothing", so that the fourth means controls the run of the vehicle so that the vehicle passes the intersection at the low speed and thereafter is accelerated after the passage of the intersection since no information on the white line is obtained, a ninth rule being such that the lane distance in the run command PR(j+1) is corrected along with one of the target point commands PO(i) set at a position before the corresponding target point N which is the intersection, the selection Q_o of the white line being set to "right" or "left", so that the fourth means controls the run of the vehicle, collecting information on the white line after the passage of the intersection, and tenth rule being such that one of the target point commands PO(i+1) is set on the same point as the target point N, at that point, the target vehicle speed V_po thereof being set to a relatively low speed, the target steering angle S_po of thereof being set to zero, the run target vehicle speed V_pr of the run command PR(j+1) being set at a constant angle, so that the fourth means controls the run of the vehicle so that the vehicle runs of the curved road at the low speed and the steering angle of the vehicle is gradually returned to the original angle when passing through a last half of the curved road.

12. An automomous vehicle as set forth in claim 9, wherein the first sensing unit includes two sets of video cameras located on a front end of the vehicle with a space apart from each other and wherein the third means includes a second sensing unit for detecting and globally deriving an absolute position of the vehicle, the second sensing unit including wheel speed sensors and gyroscope.

13. An autonomous vehicle, comprising:

a) first means for storing information on each of a plurality of predetermined road segments, a route of travel on which the vehicle is to pass to reach a destination being divided into the plurality of predetermined road segments, wherein said information includes data formatted to identify shapes of the plurality of road segments;

b) second means for determining a shape for each road segment on the basis of the stored information of the first means;

c) third means for setting before running of the vehicle control rules for the vehicle for each road segment shape on the basis of the determined shape; and

d) fourth means for determining a current running route situation, autonomously running the vehicle on the basis of the determined running route situation, and controlling the run of the vehicle on the basis of the previously set running state,

wherein said fourth means includes sensing means for spontaneously obtaining information identifying a condition of a travel route of the vehicle, whereby said fourth means runs the vehicle autonomously based on the sensed travel route condition and the set running state, and

said sensing means comprises camera means and an image processing unit, said fourth means thus autonomously running the vehicle in accordance with an image of the travel route of the vehicle and the set running state,

wherein said camera means comprises a pair of cameras for obtaining a stereo perspective image of the travel route of the vehicle and said image processing unit including means for transforming the perspective image to a plane image.

14. A method for autonomously running an autonomous vehicle, comprising the steps of:

a) storing shape information describing each of a plurality of predetermined road segments, a route of travel on which the vehicle is to pass to reach a destination being divided into the plurality of predetermined road segments;

b) determining a shape for each road segment on the basis of the stored shape information in the step (a);

c) before running of the vehicle, setting control rules for the vehicle for each road segment shape on the basis of the determined shape; and

d) controlling running of the vehicle on the basis of the previously set running state, wherein said step of storing information comprises using a pair of cameras for obtaining a stereo perspective image of at least one of the road segments of the route of travel of the vehicle, and processing the obtained stereo perspective image to provide data representing said shape information for storage.

15. A method as recited in claim 14, wherein said step of processing the obtained stereo perspective image to provide data comprises formatting the data to include start point data, radius of curvature data, path length data, end point data, and tangential direction data for the start point and the end point of the at least one road segment, and storing the formatted data as said shape information.

16. An autonomous vehicle, comprising:

a) first means for storing information on each of a plurality of predetermined road segments, a route of travel on which the vehicle is to pass to reach a destination being divided into the plurality of predetermined road segments, wherein said information includes data formatted to identify shapes of the plurality of road segments;

b) second means for determining a shape for each road segment on the basis of the stored information of the first means;

c) third means for setting before running of the vehicle control rules for the vehicle for each road segment shape on the basis of the determined shape; and

d) fourth means for determining a current running route situation, autonomously running the vehicle on the basis of the determined running route situation, and controlling the run of the vehicle on the basis of the previously set running state, wherein said fourth means determines the current running route situation responsive only to image data descriptive of road features, independently of road markers.