Patent Application
20100114373
The present disclosure is generally related to robotic machines and, more particularly, is related to robotic machines that handle heavy payloads over long distances.
It has become more and more common to consider work areas that are shared by people and robots. As such, accidents between the robots and people may also increase. The robotic machines are typically designed to have provisions for separate but changing volumes for the robotic arm and operators. The direction is toward smaller volumes for the robotic machines relative to the operators. The industry has moved from rather large stationary volumes that are entered by the people with the robotic machine off to moving volumes surrounding the moving parts of the robotic machine with people still within the possible range of the motion of the robotic machine. This allows people to enter a volume that has previously been used by the robotic machine and vice versa.
Generally after any stop, an operator verifies that a work area is free of any person and then pushes a resume “button” or device to resume operation of the robotic machine. This approach has the shortcoming of depending on manual verification, itself not as reliable it might seem, and furthermore causing a delay.
Desirable in the art is an improved robotic machine that reduces physical injuries, particularly serious injuries, as a result of accidents caused by the contact of a person with the robotic machine.
A representative robotic machine includes an end-of-arm; and a safety scanner system that scans for objects in a workspace volume around the end-of-arm. The safety scanner system determines whether to stop operations of the robotic machine based on the presence of the objects in the workspace volume.
Other systems, devices, methods, features of the invention will be or will become apparent to one skilled in the art upon examination of the following figures and detailed description. It is intended that all such systems, devices, methods, features be included within the scope of the invention, and be protected by the accompanying claims.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, the reference numerals designate corresponding parts throughout the several views. While several embodiments are described in connection with these drawings, there is no intent to limit the disclosure to the embodiment or embodiments disclosed herein. On the contrary, the intent is to cover all alternatives, modifications, and equivalents.
Exemplary systems are first discussed with reference to the figures. Although these systems are described in detail, they are provided for purposes of illustration only and various modifications are feasible. After the exemplary systems are described, examples of flow diagrams of the systems are provided to explain the manner in which a work area is scanned for objects.
This disclosure addresses the issue of scanning a workspace volume, e.g., the area around the end-of-arm of the robotic machine, to assure that no person is present in a work area. Before scanning, a first provides an obstacle free conventional boundary of the work area, typically optical in nature. In either case, a boundary around the robotic machine is provided into which persons or other unexpected items should not intrude.
This disclosure is related to mechanisms that make robotic machines more safe with an emphasis on reducing any damage to persons and equipment because of the robotic motion. The damage reduction is achieved by detection of persons or things near a payload. A mechanism, among others, for achieving this is to detect that people are not near an end-of-arm (BOA) of the robotic machines even when people may be within the possible workspace of the BOA.
The robotic machines described in this disclosure generally handle heavy payloads over long distances. However all of the described mechanism can be applied to many robotic situations and many machines used in moving material automatically or with mechanical assistance. The robotic machines utilize technologies related to position estimation, learned control effort, and command shaping that can allow the construction of lightweight, imprecise machines to achieve high-speed, accurate motion. Such technologies have been disclosed in U.S. Pat. Nos. 5,946,449, to Dickerson, et al. and 6,078,844, to Magee, et al., the entirety of which applications are expressly incorporated by reference herein.
The fabrication of the robotic machine can take a wide variety of forms.
X rails 105 are placed parallel to each other and are generally attached to a top structure (not shown), such as, a ceiling beam. A Y bridge 110 is coupled to the bottom of the X rails 105, generally at the ends of the Y bridge 110. The Y bridge 110 is positioned substantially perpendicular to the X rails 105. A control module 125 is placed on top of the Y bridge 110. The control module 125 includes a computing device, motors, and sensors, among others, that can facilitate moving the Y bridge 110 along the X rails 105 in the X direction. The Y bridge 110 is coupled to a Z beam 120, which roves along the Y bridge 110 in the Y direction.
The Z beam 120 can move up and down in the Z direction. The Z beam 120 includes a proximal and 135 and distal and 140 in which the distal end 140 is coupled to a mounting plate 145. The mounting plate 145 can include, but is not limited to, tooling devices and gripping devices. The distal end 140 of the Z beam 120 is generally referred to the end-of-arm (EOA) 130.
Current technology for example scanners by SICK inc. and others are capable of safety rated scans every 60 ins at distances up to 7 meters. The later measurement type is assumed here to be used at 0.25 degree steps in distance and take 53 ms total scan time for 180 degree scans. The scanned workspace volume moves around the work area 205 as scanners move with the EOA 130. For example, the initial scanned workspace volume may be positioned in a location of the work area 205 that a person may not be within. As the EOA 130 moves to another location of the work area 205, the scanned workspace volume also moves with the EOA 130 and may now be in the area that a person is operating the robotic machine 100.
Scanners 305, 310 (
Note that once the scanners 305, 310 are in the out position and no person has been found the robotic machine can start operations and the scanners remain in the out position. Note also that the concept can be generalized to have moveable scanners in both the X and Y directions 225, 220 so that the rectangular box of protection can be moveable in two directions.
In block 410, the safety scanner system 300 learns the pre-existing location and profiles in the X, V, and Z directions of the objects 315, 320, 330, 335. In block 415, the safety scanner system 300 scans for the presence of people in a volume around the, e.g., EOA 125, before enabling the robotic machine to operate. In block 420, the safety scanner system 300 can halt operation of the robotic machine 100 responsive to detecting a person in the workspace volumen. The scanning for the presence of people can be accomplished by way of imaging based on range, which can be described as range imaging. The current state of the art suggests that cameras will soon be able to do a very similar function.
The scanning process determines the locations of objects 315, 320, 330, 335 and scan for people such that the scanner system 300 is not fooled by the objects 315, 320, 330, 335. This learned pattern would be created relatively infrequently. The ability of robots to know the locations of the objects 315, 320, 330, 335, as described in connection with blocks 405 and 410, would be used to allow the scanning for people to be done properly
Range imaging was previously described to detect people in the work area 205. Range imaging can utilize a vision-based system that uses multiple cameras to detect anything visible within a set of programmable volumes on the basis of triangulation. A sensor head of the vision-based system can move to facilitate detecting objects in the work area 205.
Other sensors can be used to reliably find people or other objects within the work area 205. The sensors can distinguish people from objects 315, 320, 330, 335. Some alternatives are described are follows:
Radio beacons can be used to track all objects, such as people, if the radio beacons are attached to the objects. The objection to this is reliability as it requires that people wear the devices and maintain a good position relative to RF reflective surfaces, typically metals or other conductors.
The systems and methods disclosed herein can be implemented in software, hardware, or a combination thereof. In some embodiments, the system and/or method is implemented in software that is stored in a memory and that is executed by a suitable microprocessor (μP) situated in a computing device. However, the systems and methods can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device. Such instruction execution systems include any computer-based system, processor-containing system, or other system that can fetch and execute the instructions from the instruction execution system. In the context of this disclosure, a “computer-readable medium” can be any means that can contain, store, communicate, propagate, or transport the program for use by, or in connection with, the instruction execution system. The computer readable medium can be, for example, but not limited to, a system or propagation medium that is based on electronic, magnetic, optical, electromagnetic, infrared, or semiconductor technology.
Specific examples of a computer-readable medium using electronic technology would include (but are not limited to) the following: an electrical connection (electronic) having one or more wires; a random access memory (RAM); a read-only memory (ROM); an erasable programmable read-only memory (EPROM or Flash memory). A specific example using magnetic technology includes (but is not limited to) a portable computer diskette. Specific examples using optical technology include (but are not limited to) optical fiber and compact disc read-only memory (CD-ROM).
Note that the computer-readable medium could even be paper or another suitable medium on which the program is printed. Using such a medium, the program can be electronically captured (using, for instance, optical scanning of the paper or other medium), compiled, interpreted or otherwise processed in a suitable manner, and then stored in a computer memory. In addition, the scope of the certain embodiments of the present disclosure includes embodying the functionality of the preferred embodiments of the present disclosure in logic embodied in hardware or software-configured mediums.
It should be noted that any process descriptions or blocks in flowcharts should be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process. As would be understood by those of ordinary skill in the art of the software development, alternate embodiments are also included within the scope of the disclosure. In these alternate embodiments, functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved.
This description has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments discussed, however, were chosen to illustrate the principles of the disclosure, and its practical application. The disclosure is thus intended to enable one of ordinary skill in the art to use the disclosure, in various embodiments and with various modifications, as are suited to the particular use contemplated. All such modifications and variation are within the scope of this disclosure, as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly and legally entitled.
This application claims the benefit of U.S. provisional patent application Ser. No. 61/110,374 filed Oct. 31, 2008, the entirety of which application is expressly incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61110374 | Oct 2008 | US |
