Electricity: motive power systems – Positional servo systems – Vehicular guidance systems with single axis control
Reexamination Certificate
1995-11-07
2001-07-03
Salata, Jonathan (Department: 2837)
Electricity: motive power systems
Positional servo systems
Vehicular guidance systems with single axis control
C180S168000, C056S01020F
Reexamination Certificate
active
06255793
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and related systems for navigation in an enclosed area. More particularly, the invention relates to method and apparatus which can be used to cause an automated device to move and to perform predetermined tasks within an enclosed area.
BACKGROUND OF THE INVENTION
The use of automated devices is widespread nowadays, and finds countless applications. For instance, robots perform very precise and delicate tasks in the construction of electronic devices, or in medicine and aviation. Robots are also used in uses which require motion, notably, for automatic warehouses, where goods are retrieved and stored by means of computer-actuated robots. Other applications include, e.g., fetching raw materials in the course of industrial manufacturing, and removing and packaging finished pieces. In everyday's life, attempts have also been made to exploit robots for lawn mowing and for vacuum cleaning.
The major drawback of mobile robots, which the art has so far been unable to overcome, is the fact that their movements are limited to well predefined paths, normally requiring that they move along rails, or that they be provided with expensive navigation signs, positioned within the area in which they move, which operate as “stations” which redefine the exact position of the robot, and from which the program may direct the robot to the next station. These intermediate signs are expensive, take up space, and are inconvenient to use, since they must be very precisely positioned and cannot be easily moved.
Another approach involves providing an area delimited by boundaries recognizable by the robot, and permitting the robot to effect a random walk therein, during which random walk it carries out its tasks. This approach entails severe drawbacks: first of all, when the robot moves within a predefined area by random walk, there is no way to ensure that the whole area will be covered by the tool which must operate thereon. As a result, even though the robot may operate for a long period of time, unworked areas may be left at the end of the operation. Secondly, if the area to be worked is irregular, or if it presents “islands”, viz. areas which must not be worked, the random walk may lead to imperfect operation around such islands, as well as at those locations where the perimeter is of irregular shape. Thirdly, because the operation of the robot is not programmed to obtain a predetermined coverage, it is necessary to allow the random walk to go on for a long period of time, so as to increase the chances of covering a major portion of the area to be worked. This is not only energy consuming, but also leads to an increased wear of the equipment, and may also be environmentally undesirable due, e.g., to noise or other pollution caused by the operation of the robot. Even if the robot is operated by sun energy, most of the aforesaid problems are not overcome, and additional problems exists, connected with such a mode of operation. For instance, the robot may not work properly in areas of the world where sun radiation is scarce or low, and may be inoperative for substantial parts of the day, e.g., on cloudy weather.
A further approach involves preprogramming the robot with a blueprint of its designated area of operation, such as a floor map of a building in which a robot is to operate. This approach has two major drawbacks:
a) it requires preprogramming by the user, which makes in unpractical for extensive consumer use; and
b) it requires that such preprogramming is repeated each time something changes in the work area.
It is therefore clear that it would be highly desirable to be able to provide means by which automated mechanisms may move and perform their task within a predetermined area, without being hindered by the need for predefined paths and rails, or by intermediate navigation signs or preprogramming, and which may carry out their task in a predetermined manner, without relying on random occurrences and/or on unstable energy sources.
SUMMARY OF THE PRESENT INVENTION
It has now been found, and this is an object of the present invention, that it is possible to free automated mechanisms operating within an enclosed zone from the need for preprogramming or predefined paths and rails, and from the need for intermediate navigation aids, and this to overcome the drawbacks of the prior art and to provide means by which a robot may perform its tasks within an enclosed area in a manner free from such limitations, with high precision and in a minimal period of time.
It is an object of the present invention to provide a navigation method which fulfills the aforementioned goals.
It is another object of the invention to provide means which can be used in systems utilizing the method of the invention.
Other objects of the invention will become apparent as the description proceeds.
The method for automatically operating a robot within an enclosed area, according to the invention, comprises the steps of:
providing a boundary along the perimeter of the working area, the said boundary being detectable by a proximity sensor;
providing boundaries along the perimeter of each area enclosed in the working area, in which it is desired that the robot should not operate, the said boundaries also being detectable by a proximity sensor;
providing a proximity sensor positioned on the robot;
providing processing means connected to the said proximity sensor and receiving an input therefrom;
providing location means on the said robot, to determine the coordinates of the robot relative to an arbitrary origin, at any specific time;
providing direction finding means;
providing memory means to store values generated by the said processing means and, optionally, by the said location means;
causing the robot to move along each of the boundaries provided around or within the said working area, to detect the said boundaries and to memorize their shape, and to store in the memory means values representative of the coordinates of the said boundaries, relative to an arbitrary origin, thereby to generate a basic map of the working area;
when the robot is to operate within the said area:
(a) causing the robot to start from a starting point having known coordinates within the basic map of the working area;
(b) continuously determining the coordinates of the robot by analyzing data obtained from the location means and by detecting the vicinity of a boundary; and
(c) correcting the actual position of the robot on the basic map by comparing the calculated and the actual coordinates of each detected boundary.
By “robot” it is meant to indicate any autonomously operating device, which may carry out pre-programmed tasks with one or more tools, while moving in the process from one location to another.
According to a preferred embodiment of the invention, the location means comprise movement measuring means, such as an odometer or the like device, to measure the distance traveled by the robot, e.g., by measuring the number of revolutions of a wheel. As stated, direction finding means are also provided, so as to provide information on the direction in which the robot travels at any given time, which is needed in order to determine the coordinates of the robot on the map. The direction finding means can be of any suitable type, e.g., may comprise a compass.
While, as stated, it is an object of the invention to utilize relatively inexpensive devices for the operation of the robot, it is of course possible to employ more expensive and sophisticated equipment, without exceeding the scope of the invention. Thus, for instance, it is possible to employ range-finding means, such as a laser range-finder or RF range finders, to determine the distance of the robot from one or more given locations, at any given time, instead of, or in addition to, using an odometer or the like device to measure the distance traveled. However, any such modifications will be apparent to the skilled person, and therefore are not discussed herein in detail.
According to a preferred embodiment of the invention, the b
Abramson Shai
Dror Gideon
Peless Ehud
Friendly Robotics Ltd.
Heid David W.
Salata Jonathan
Skjerven Morrill & MacPherson LLP
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