Method for producing a cellularly structured environment map of a self-propelled, mobile unit that orients itself in the environment at least with the assistance of sensors based on wave refection

• US 5,677,836 A
• Filed: 02/24/1995
• Issued: 10/14/1997
• Est. Priority Date: 03/11/1994
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Bauer, Rudolf
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): WALDER, STEPHEN JOSEPH
• Application Number:
  US08/393,820
• Time in Patent Office: 963 Days
• Field of Search: 364/449, 364/424.02, 364/424.027, 364/424.029, 364/424.031, 364/449.1, 364/460, 364/461, 180/167, 180/168, 180/169
• US Class Current: 701/23
• CPC Class Codes: A47L 11/4011 Regulation of the cleaning machine by electric means; Control systems and remote control systems therefor
• CPC Class Codes: A47L 11/4061 Steering means; Means for avoiding obstacles; Details related to the place where the driver is accommodated
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• CPC Class Codes: G05D 1/0257 using a radar radar systems designed for anti-collision purposes between land vehicles or between land vehicle and fixed obstacles G01S13/931
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

The method produces an improved cellularly structured environment map of a self-propelled mobile unit which orients itself using sensors based on wave reflection. In detail, the following measures are implemented. First, an error of discrete representation in the positional determination of the self-propelled mobile unit is avoided in that the position of the self-propelled mobile unit within an originating cell of the coordinate system of the environment map is also used for identifying the location of obstacles. Further, a smaller cell size is employed in the proximity of the self-propelled mobile unit in order to facilitate maneuvering between obstacles located close to one another. Further, two separate grid maps are maintained, one containing the unit with a rotational orientation and the other being rotated by a rotational angle relative to the global environment map for a fast occupation of a plurality of cells with values. Examples of such self-propelled mobile units are household robots, self-propelled vacuums and industrial transport vehicles.

Claims

1. A method for producing a cellularly structured environment map with a self-propelled mobile unit that orients itself in an environment at least using sensors based on wave reflection, the method comprising the steps of:

providing dimensions of the mobile unit, the mobile unit having a sensor, and providing a location of the sensor on the mobile unit, a coordinate reference point being determined from a current position of the mobile unit in an originating cell utilizing the dimensions of the mobile unit and the location of the sensor on the mobile unit;

determining a distance, using the sensor on the self-propelled mobile unit, from an environmental article to the sensor during a measurement wherein the self-propelled mobile unit is in an originating cell of the environment map;

using a current position of the self-propelled mobile unit at a point in time of the measurement as an exact position of the coordinate reference point within the originating cell of the environment map; and

identifying at least one cell, taking the current position, the distance and an arranged position of the sensor relative to the coordinate reference point into consideration, occupied by the environmental article and allocating to said at least one cell a degree of occupancy for determining a location of the environmental article in the environment map.

2. The method according to claim 1, wherein the method further comprises using cells of different sizes for producing the environment map.

3. The method according to claim 2, wherein a smaller cell size is used in a proximity of the self-propelled mobile unit and a larger cell size is used away from the proximity of the self-propelled mobile unit.

4. The method according to claim 1, wherein the method further comprises:

producing a local environment map and a global environment map with the self-propelled mobile unit, providing cells in the local environment map that all have a fixed topical relationship to the self-propelled mobile unit, and providing cells in the global map that have a specific, variable rotation relative to the self-propelled mobile unit resulting from motion of the self-propelled mobile unit and defined by a rotational angle;

only translating the cells of the global grid during a motion of the self-propelled mobile unit and establishing a different rotational angle dependent on the motion;

deriving the local environment map from the global environment map by applying trigonometric functions using the rotational angle, the local environment map being derived therefrom for an evaluation that affects a plurality of cells of the environment map; and

using the global environment map for a route planning of the self-propelled mobile unit.

5. A method for producing a cellularly structured environment map with a self-propelled mobile unit that orients itself in an environment at least using sensors, the method comprising the steps of:

providing a cellularly structured environment map having cells, a smaller cell size used in a proximity of the self-propelled mobile unit and a larger cell size being used away from the proximity of the self-propelled mobile unit;

providing dimensions of the mobile unit, the mobile unit having a sensor, and providing a location of the sensor on the mobile unit, a coordinate reference point being determined from a current position of the mobile unit in an originating cell utilizing the dimensions of the mobile unit and the location of the sensor on the mobile unit;

determining a distance, using the sensor on the self-propelled mobile unit, from an environmental article to the sensor during a measurement wherein the self-propelled mobile unit is in an originating cell of the environment map;

using a current position of the self-propelled mobile unit at a point in time of the measurement as an exact position of the coordinate reference point within the originating cell of the environment map; and

identifying at least one cell, taking the current position, the distance and an arranged position of the sensor relative to the coordinate reference point into consideration, occupied by the environmental article and allocating to said at least one cell a degree of occupancy for determining a location of the environmental article in the environment map.

6. A method for producing a cellularly structured environment map with a self-propelled mobile unit that orients itself in an environment at least using sensors, the method comprising the steps of:

producing a local environment map and a global environment map with the self-propelled mobile unit, providing cells in the local environment map that all have a fixed topical relationship to the self-propelled mobile unit, and providing cells in the global map that have a specific, variable rotation relative to the self-propelled mobile unit resulting from motion of the self-propelled mobile unit and defined by a rotational angle;

only translating the cells of the global grid during a motion of the self-propelled mobile unit and establishing a different rotational angle dependent on the motion;

deriving the local environment map from the global environment map by applying trigonometric functions using the rotational angle, the local environment map being derived therefrom for an evaluation that affects a plurality of cells of the environment map;

providing dimensions of the mobile unit, the mobile unit having a sensor, and providing a location of the sensor on the mobile unit, a coordinate reference point being determined from a current position of the mobile unit in an originating cell utilizing the dimensions of the mobile unit and the location of the sensor on the mobile unit;

determining a distance, using the sensor on the self-propelled mobile unit, from an environmental article to the sensor during a measurement wherein the self-propelled mobile unit is in an originating cell of the global environment map;

using a current position of the self-propelled mobile unit at a point in time of the measurement as an exact position of the coordinate reference point within the originating cell of the global environment map; and

identifying at least one cell, taking the current position, the distance and an arranged position of the sensor relative to the coordinate reference point into consideration, occupied by the environmental article and allocating to said at least one cell a degree of occupancy for determining a location of the environmental article in each of the global environment map and the local environment map; and

using the global environment map for a route planning of the self-propelled mobile unit.

7. A method for producing a cellularly structured environment map with a self-propelled mobile unit that orients itself in an environment at least using sensors based on wave reflection, the method comprising the steps of:

providing dimensions of the mobile unit, the mobile unit having a sensor, and providing a location of the sensor on the mobile unit, a coordinate reference point being determined from a current position of the mobile unit in an originating cell utilizing the dimensions of the mobile unit and the location of the sensor on the mobile unit;

determining a distance, using the sensor on the self-propelled mobile unit, from an environmental article to the sensor during a measurement wherein the self-propelled mobile unit is in an originating cell of the environment map;

using a current position of the self-propelled mobile unit at a point in time of the measurement as an exact position of the coordinate reference point within the originating cell of the environment map; and

identifying at least one cell, taking the current position, the distance and an arranged position of the sensor relative to the coordinate reference point into consideration, occupied by the environmental article and allocating to said at least one cell a degree of occupancy for determining a location of the environmental article in the environment map, a smaller cell size being used in a proximity of the self-propelled mobile unit and a larger cell size being used away from the proximity of the self-propelled mobile unit.

8. A method for producing a cellularly structured environment map with a self-propelled mobile unit that orients itself in an environment at least using sensors based on wave reflection, the method comprising the steps of:

determining a distance, using a sensor on the self-propelled mobile unit, from an environmental article to the sensor during a measurement wherein the self-propelled mobile unit is in an originating cell of the environment map;

using a current position of the self-propelled mobile unit at a point in time of the measurement as an exact position of a coordinate reference point within the originating cell of the environment map;

identifying at least one cell, taking the current position, the distance and an arranged position of the sensor relative to the coordinate reference point into consideration, occupied by the environmental article and allocating to said at least one cell a degree of occupancy for determining a location of the environmental article in the environment map;

using cells of different sizes for producing the environment map, a smaller cell size being used in a proximity of the self-propelled mobile unit and a larger cell size being used away from the proximity of the self-propelled mobile unit.