Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Automatic route guidance vehicle
Reexamination Certificate
2001-06-29
2003-09-30
Arthur, Gertrude (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Automatic route guidance vehicle
C701S028000, C180S169000, C372S012000
Reexamination Certificate
active
06629028
ABSTRACT:
The entire disclosure of Japanese Patent Application No. 2000-196977 filed on Jun. 29, 2000 including specification, claims, drawings and summary are incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for instructing target positions for mobile bodies, a method for controlling transfer thereof, and a method as well as a system of optical guidance therefor, and more particularly to a method for instructing target positions for mobile bodies, a method for controlling transfer thereof, and a method as well as a system of optical guidance therefor, all of which are suitably used in the case where mobile bodies such as wheeled or walking mobile robots are guided.
2. Description of the Related Art
In general, a mobile body such as an autonomous omni-directional mobile robot has been known as a mobile body being movable in a given environment.
Incidentally in case of transfer in such mobile body, it is required to specify a position of coordinates of the mobile body in question in an environment wherein the mobile body can be transferred in order to set a position that is a target to be determined as its goal by the mobile body in question (hereinafter referred to as “target position”). The actual position of coordinates of a mobile body can be generally determined on the basis of dead-reckoning, for example such as from the odometry data of the mobile body.
However, when a position of coordinates is determined only based on the dead-reckoning data of a mobile body, there has been such problem that errors defined between the position of coordinates in the mobile body determined on the basis of the dead-reckoning data of the mobile body and a position of coordinates on which the mobile body resides in reality are accumulated, because of a limit in precision for working traveling wheels or legs in the mobile body and slippage (running idle) of such traveling wheels or legs in the case when the mobile body travels in a given environment.
For this reason, it has been necessary for compensating a position of coordinates obtained on the basis of the dead-reckoning data of a mobile body by the use of either means for functioning as sensors such as sonar, gyroscope, and camera, or land-marks in a given environment in order to specify correctly a position where the mobile body resides actually in the environment.
On the other hand, known methods of motion control of a mobile body in an environment rely on, for example, a common coordinate system wherein positions of coordinates of mobile bodies in the environment and environmental objects are computed, and the respective positions of coordinates obtained as a result of the computation are represented in an environmental model indicating the environment thereof.
In this case, it is required that the newest positions of coordinates are to be supplied always into the environmental model to acquire the newest position of a mobile body in the environment.
As described above, however, there are errors each of which exists between a position of coordinates of a mobile body determined on the basis of dead-reckoning data of the mobile body in question and a position of coordinates of the mobile body where the mobile body resides actually, and such errors are accumulated with travel of the mobile body, so that a discrepancy between the actual position of the mobile body in the environment and its computed one in the environment model increases over travel time and becomes substantial.
In this respect, if target positions towards which the mobile body is to be transferred are set on the basis of coordinate positions of the mobile body in the environmental model, which do not correspond to that of the mobile body residing actually in the environment, there has been such a problem that it results in unexpected dangerous motion of the mobile body in the environment.
Accordingly, to exclude such unexpected dangerous motion of the mobile body in the environment in the case when target positions towards which the mobile body is to be transferred in the environment, the above-described discrepancy (the discrepancy between the actual position of the mobile body in the environment and its computed coordinate positions in the environment model must be compensated).
The above-described problem can be eliminated if a target position is indicated in the environment and its numerical coordinates are implicitly transmitted to the mobile body, which detects the indicated target positions and evaluates its relative coordinates by means of a visual feedback. In this case, a transformation between the common coordinate system and the mobile body's coordinate system becomes less relevant or is not even required, and the above-described discrepancy is compensated by means of visual feedback.
A variety of manners has been proposed heretofore as methods for guiding mobile bodies.
Namely, U.S. Pat. No. 5,622,236 discloses to draw a guidance line on a floor surface, or U.S. Pat. No. 4,947,094 discloses to draw a guidance line on a ceiling. Furthermore, it is disclosed by U.S. Pat. No. 5,815,825 to use magnetic markers in a floor surface. Moreover, it is disclosed by U.S. Pat. Nos. 4,773,018 and 4,858,132 to track a stationary light source.
Besides, a vehicle guidance by means of a laser beam is proposed and disclosed in U.S. Pat. No. 5,285,205 wherein a stationary laser indicates a path direction to a human operator situated inside the vehicle, and concerning this method, see also U.S. Pat. No. 4,856,896.
Further, a scanning laser mounted on a vehicle is proposed and disclosed in U.S. Pat. No. 4,790,402 wherein the laser serves as a transmitter-receiver to measure relative distances to the surrounding objects.
Moreover, reflective beacons in the environment are proposed in U.S. Pat. Nos. 4,855,915, 4,846,297, and 4,817,000.
Besides, indication of a target by means of projection of laser light onto the target where it forms a light dot (spot) is known, for instance, in a field of weapons. Namely, a device to adjust the laser optical axis with the axis of the weapon is proposed in U.S. Pat. No. 4,916,713.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention has been made in view of the prior art as described above, and an object of the invention is to provide method for instructing target positions for mobile bodies wherein target positions in the case where the mobile bodies such as mobile robots can be instructed, a method for controlling movements thereof, and a method as well as a system of optical guidance therefor in accordance with a manner different from the prior art as described above.
Furthermore, another object of the present invention is to provide a method for instructing target positions for mobile bodies, which is used suitably in the case where the mobile bodies set target positions towards which the respective mobile bodies are to be transferred in an environment where a number of the mobile bodies such as mobile robots reside, a method for controlling transfer thereof, and a method as well as a system of optical guidance therefor.
Besides, another object of the present invention is to provide a method for instructing target positions for mobile bodies, which is used suitably in the case where a human being sets target positions towards which the mobile bodies are to be transferred in an environment where a number of the mobile bodies such as mobile robots reside, a method for controlling transfer thereof, and a method as well as a system of optical guidance therefor.
In order to achieve the above-described objects, a method for instructing target positions of at least one or more of mobile bodies contained movably in a predetermined environment according to the present invention comprises light beacons being produced by a light beam projecting device in a surface on which the mobile bodies are to be transferred, whereby target positions towards which the mobile bodies are to be transferred being instructed.
According to the present invention one mobile bod
Asama Hajime
Paromtchik Igor E.
Arthur Gertrude
Birch & Stewart Kolasch & Birch, LLP
Riken
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