Method for assuring a safety interval of a self-propelled mobile unit

• US 5,657,225 A
• Filed: 04/21/1995
• Issued: 08/12/1997
• Est. Priority Date: 04/22/1994
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Bauer, Rudolf
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/426,692
• Time in Patent Office: 844 Days
• Field of Search: 364/424.01, 364/424.02, 364/460, 364/461, 364/424.027, 364/424.029, 180/167, 180/168, 180/169, 318/587, 340/435
• US Class Current: 701/23
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165

Abstract

The method provides a better incorporation of a defined safety interval from obstacles in the route planning of a self-propelled mobile unit. By contrast to methods that were hitherto standard, a shell with equidistant spacing from a housing of the self-propelled mobile unit is not placed around the mobile unit; rather, the safety interval is calculated via the route at a drive wheel of the self-propelled mobile unit. That is, the kinematics of the self-propelled mobile unit are first used in the calculation of the safety interval from obstacles. The advantage is that better maneuverability is achieved between obstacles located close to one another.

Claims

1. A method for controlling a self-propelled mobile unit, comprising the steps of:

providing the self-propelled mobile unit with motion kinematics as a function of drive and steering properties of the mobile unit; and

calculating via the motion kinematics a safety interval to be observed between the mobile unit, when moving, and an obstacle, the safety interval being prescribed as travel distance of the unit for traversing the safety interval; and

controlling the self-propelled mobile unit not to move closer to an obstacle than said safety interval.

2. The method according to claim 1, wherein the method further comprises calculating a safety zone around the self-propelled mobile unit with the steps of:

providing a starting position and a starting steering angle of the self-propelled mobile unit;

calculating and noting for a plurality of steering angles between 0° and

360°

, via the motion kinematics after at least forward travel of the mobile unit from the starting position and based on the safety interval as a constant travel distance, a final position of the self-propelled mobile unit;

determining, taking a contour line of the self-propelled mobile unit into consideration, the safety zone associated with the starting position of the self-propelled mobile unit as joined sets of areas that are framed by a contour line of respective final positions of the unit.

3. The method according to claim 2, wherein the safety zone is calculated only once for a respective, prescribed safety interval and is carried along by the mobile unit when moving.

4. The method according to claim 2, wherein the safety zone comprises a front safety zone in front of the self-propelled mobile unit, the front safety zone being calculated by forward travel of the mobile unit, and a rear safety zone behind the self-propelled mobile unit, the rear safety zone being calculated by traveling of the mobile unit in reverse.

5. The method according to claim 1, wherein the method further comprises the steps of:

providing a cellularly structured map having cells, and determining occupied cells in the cellularly structured environment map which can be reached by movement of the mobile unit by the safety interval.

6. The method according to claim 1, wherein the motion kinematics is a three-wheel kinematics.

7. The method according to claim 1, wherein the method further comprises route planning for the self-propelled mobile unit using the safety interval to avoid collisions with obstacles by the self-propelled mobile unit.

8. A method for controlling a self-propelled mobile unit, comprising the steps of:

providing the self-propelled mobile unit with predetermined motion kinematics related to drive and steering properties of the mobile unit; and

calculating via the motion kinematics at least one safety interval to be observed between the mobile unit, when moving, and an obstacle, the at least one safety interval being prescribed as travel distance of the unit for traversing the at least one safety interval; and

controlling the self-propelled mobile unit not to move closer to an obstacle than said safety interval.

9. The method according to claim 8, wherein the method further comprises calculating at least one safety zone around the self-propelled mobile unit with the steps of:

providing a starting position and a starting steering angle of the self-propelled mobile unit;

calculating and noting for a plurality of steering angles between 0° and

360°

, via the motion kinematics after at least forward travel of the mobile unit from the starting position and based on the at least one safety interval as a constant travel distance, a final position of the self-propelled mobile unit;

determining, taking a contour line of the self-propelled mobile unit into consideration, the at least one safety zone associated with the starting position of the self-propelled mobile unit as joined sets of areas that are framed by a contour line of respective final positions of the unit.

10. The method according to claim 9, wherein the at least one safety zone is calculated only once for a respective, prescribed safety interval and is carried along by the mobile unit when moving.

11. The method according to claim 9, wherein the at least one safety zone comprises a front safety zone in front of the self-propelled mobile unit, the front safety zone being calculated by forward travel of the mobile unit, and a rear safety zone behind the self-propelled mobile unit, the rear safety zone being calculated by traveling of the mobile unit in reverse.

12. The method according to claim 8, wherein the method further comprises the steps of:

providing a cellularly structured map having cells, and determining occupied cells in the cellularly structured environment map which can be reached by movement of the mobile unit by the at least one safety interval.

13. The method according to claim 8, wherein the motion kinematics is a three-wheel kinematics.

14. The method according to claim 8, wherein the method further comprises route planning for the self-propelled mobile unit using the at least one safety interval to avoid collisions with obstacles by the self-propelled mobile unit.

15. A method for controlling a self-propelled mobile unit, comprising the steps of:

providing the self-propelled mobile unit with motion kinematics as a function of drive and steering properties of the mobile unit;

calculating via the motion kinematics a safety interval to be observed between the mobile unit, when moving, and an obstacle, the safety interval being prescribed as travel distance of the unit for traversing the safety interval;

providing a starting position and a starting steering angle of the self-propelled mobile unit;

calculating and noting for a plurality of steering angles between 0° and

360°

, via the motion kinematics after at least forward travel of the mobile unit from the starting position and based on the safety interval as a constant travel distance, a final position of the self-propelled mobile unit; and

determining, taking a contour line of the self-propelled mobile unit into consideration, a safety zone associated with the starting position of the self-propelled mobile unit as joined sets of areas that are framed by a contour line of respective final positions of the unit; and

controlling the self-propelled mobile unit not to move closer to an obstacle than said safety interval.

16. The method according to claim 15, wherein the safety zone is calculated only once for a respective, prescribed safety interval and is carried along by the mobile unit when moving.

17. The method according to claim 15, wherein the safety zone comprises a front safety zone in front of the self-propelled mobile unit, the front safety zone being calculated by forward travel of the mobile unit, and a rear safety zone behind the self-propelled mobile unit, the rear safety zone being calculated by traveling of the mobile unit in reverse.

18. The method according to claim 15, wherein the method further comprises the steps of:

providing a cellularly structured map having cells, and determining occupied cells in the cellularly structured environment map which can be reached by movement of the mobile unit by the safety interval.

19. The method according to claim 15, wherein the motion kinematics is a three-wheel kinematics.

20. The method according to claim 15, wherein the method further comprises route planning for the self-propelled mobile unit using the safety interval to avoid collisions with obstacles by the self-propelled mobile unit.