The invention relates to an autonomous moving apparatus performing required operations such as movement while detecting and avoiding an obstacle.
There are available two methods of providing an autonomous moving apparatus with an obstacle detecting element for avoiding an obstacle: by using a supersonic or infrared sensor as the obstacle detecting element or by using as it a radar device for scanning a horizontal plane.
To detect an obstacle with the former obstacle detecting element, that is, with a supersonic or infrared sensor, however, many sensors each having a small detection area need to be arranged in order to accurately detect the position of an obstacle in a wide detection area (see Japanese Unexamined Patent Publication No. 7-49381).
As shown in FIG. 15(a), for example, in an autonomous moving apparatus 1 mounted with an obstacle sensor 5 utilizing a supersonic wave or an infrared ray and the sensor 5 having a wide detection area 50, a wide detection area is detected by few sensors 5. With only one sensor 5 alone, however, an obstacle 9, even if detected by it, cannot be decided on whether it is located at a position e or f. This means that the obstacle cannot clearly be recognized and so cannot be avoided efficiently both in direction and in distance.
Even if the sensor 5 with the small detection area 50 is arranged many as shown in FIG. 15(b), such a small obstacle 9 as indicated by a reference sign g may be missed and also such an obstacle 9 indicated by a reference sign h cannot be detected that would not reflect a supersonic wave or an infrared ray toward a receiving element. To guard against this, as shown in FIG. 15(c), it is necessary to arrange many sensors such as a sensor 5xe2x80x2 that bridges the gap between the detection areas 50 or a sensor 5xe2x80x3 that has a different detection angle. Such an arrangement of many sensors, however, not only increases the costs but also needs complicated processing to eliminate interference between the sensors.
If, as shown in FIG. 16, such a radar device 4 having a detection area 40 is used that scans a horizontal plane in a range of, for example, 180xc2x0, on the other hand, it is possible to accurately detect an obstacle in position and distance. If the obstacle 9 happens to be a chair or a table and therefore only its leg 90 is spotted on a scanning surface, the radar device 4 can recognize the leg 90 but not an upper structure 91 of the obstacle 9 such as a roof. Accordingly, the autonomous moving apparatus 1 decides that it can pass through between the legs 90 and so moves straightly without avoiding it, thus eventually collide with the upper structure 91. xe2x80x9cLxe2x80x9d in the figure indicates a set distance (radius) within which an obstacle can be detected.
If an obstacle detecting element by use of the first optional supersonic or infrared sensor and that by use of the second optional radar device are only combined, collision with an obstacle can be avoided but the problem of an inefficiency inherent to the former detecting element cannot be avoided in avoiding an obstacle that can be detected by it.
In view of the above, it is an object of the present invention to provide an autonomous moving apparatus that can surely detect an obstacle and, moreover, can avoid it efficiently.
An autonomous moving apparatus according to the present invention moving to a destination while detecting an obstacle and avoiding it includes a scan-type sensor for scanning a horizontal plane in the travelling direction to detect a position of an obstacle, a non-scan-type sensor for detecting, without scanning, an obstacle in a space different from the scanning plane of the scan-type sensor, an obstacle detecting element for always detecting an obstacle based on detection information from the scan-type sensor and, when an obstacle was detected by the scan-type sensor, operating the non-scan-type sensor to thereby guess the position of the obstacle based on the detection information from both the scan-type and non-scan-type sensors, and a controller for controlling travelling to a destination based on a position of the obstacle detected by the obstacle detecting element.
By this aspect of the present invention, only when an obstacle was detected by the scan-type sensor, the, non-scan-type sensor is activated so that the position of the obstacle may be guessed on the basis of detection information from both the scan-type and non-scan-type sensors, thus enabling efficient detection as compared to an approach whereby the detection information from both sensors is used always.
Another autonomous moving apparatus according to the present invention moving to a destination while detecting an obstacle and avoiding it includes a scan-type sensor for scanning a horizontal plane in a travelling direction to detect a position of an obstacle, a non-scan-type sensor for detecting, without scanning, an obstacle in a space different from the scanning plane of the scan-type sensor, a specific-configuration detecting element for guessing a shape of a detected object based on its distance information for each scanning angle of the scan-type sensor to thereby detect a set specific configuration, an obstacle detecting element for guessing a position of an obstacle based on detection information from both the scan-type and non-scan-type sensors if a specific configuration was detected by the specific-configuration detecting element and, otherwise, guessing the position of the obstacle based on only the detection information from the scan-type sensor, and a controller for controlling travelling toward a destination based on a detected position of the obstacle obtained from the obstacle detecting element.
By this aspect of the present invention, when the specific-configuration detecting element guessed a shape of a detected object based on information of a distance of the detected object sent from the scan-type sensor to thereby detect a specific configuration, the position of the obstacle is guessed based on the detection information from both the scan-type and non-scan-type sensors. Thus, the non-scan-type sensor is activated only in a region which have therein such an obstacle that cannot be detected only by the scan-type sensor to thereby guess a specific configuration of obstacle and efficiently detect it, thus enabling avoiding the obstacle surely and efficiently.
Also, if the non-scan-type sensor is active always, it may recognize an obstacle in its detection area even when it exists only at an edge of that area. Accordingly, for example, the apparatus problematically decides it cannot pass through a narrow passage between a wall and an obstacle even when there is a space therebetween wide enough to pass through. Such a problem can be solved by the invention, by which only the scan-type sensor is activated in such a case.
The specific-configuration detecting element has a memory for storing beforehand the information required to detect a columnar object as a specific configuration so that based on a series of detected object distance data pieces obtained from the scan-type sensor it can recognize a shape given by this data as a specific configuration when a difference between distances indicated by the adjacent data pieces is within a range set in the memory, a width of the detected object guessed from the data is within a range set in the memory, and a distance indicated by data pieces on both sides of this guessed object""s data is larger than a distance set in the memory and also continues as long as at least a width set in the memory. Thus, the columnar object can be detected as a specific configuration, thus detecting an object including a chair or a table with legs that has a roof overhung in the air.
The obstacle detecting element guesses the position of an obstacle based on detection information from both the scan-type and non-scan-type sensors if the distance with respect to a specific configuration of the obstacle detected by the specific-configuration detecting element is smaller than a value set in the memory and, otherwise or if no specific configuration was detected, guesses the position of the obstacle based on only the detection information from the scan-type sensor. Thus, when the distance with respect to an object with a specific configuration is large or no specific configuration of object cannot be detected, only the scan-type sensor is used in detection, thus enabling avoiding the obstacle efficiently.
The obstacle detecting element activates the non-scan-type sensor when the specific-configuration detecting element provides a detection output. Thus, power dissipation can be reduced at the non-scan-type sensor.