Path finding method for a self-propelled mobile unit

US5920172A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventor

• Rudolf Bauer · Hallerndorf, DE

Key dates

• Filing date: Dec 3, 1996
• Grant date: Jul 6, 1999
• Expiry date: Dec 3, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G05D1/0255
• WIPO field: Control
• WIPO sector: Instruments

Abstract

With the improved path finding method a self-propelled mobile unit determines a path around obstacles. A heuristic avoidance strategy is used, whereby the mobile unit, when encountering an obstacle, first evades by taking a first direction and implements an avoidance procedure up to a limit value if it cannot move around the obstacle. Subsequently, the unit returns to the point of departure of the avoidance maneuver and attempts to evade in the other direction. If it is likewise not possible to move around the obstacle in this direction before the limit value is reached, the barrier for the deviation in the avoidance maneuver is incremented. The unit then again attempts to move around the obstacle, first in the original avoidance direction. The limit value is increased again after respectively two more abortive attempts. The procedure is implemented until a path around the obstacle has been found and the destination can be reached. This avoids situations wherein a self-propelled mobile unit remains captured in an endless loop due to an avoidance maneuver in front of an extensive obstacle, whereby it attempts to move around the obstacle toward the right and toward the left but is pr…