Patent Application
20210023714
Industrial robots are well known in the art. Such robots are intended to replace human workers in a variety of assembly tasks. It has been recognized that in order for such robots to effectively replace human workers in increasingly more delicate and detailed tasks, it will be necessary to provide sensory apparatus for the robots which is functionally equivalent to the various senses with which human workers are naturally endowed, for example, sight, touch, etc.
In robotic picking applications for small part assembly, warehouse/logistics automation, food and beverage, etc., a robot gripper needs to pick an object, then insert/place it accurately into another part. There are some traditional solutions: (1.) Customized fingers on the gripper can self-align the part to a fixed location relative to the gripper. But for different shape of the part, a different type of finger has to be made and changed. (2.) After picking up the part, the robot brings the part in front of a camera and a machine vision system detects the location of the part relative the gripper. But this extra step increases the cycle time for the robot system. (3.) The part is placed on a customized fixture and the robot is programmed to pick up the part at the same location each time. But various fixtures have to be made for different parts which may not be cost effective to produce.
Of particular importance for delicate and detailed assembly tasks is the sense of touch. Touch can be important for close-up assembly work where vision may be obscured by arms or other objects, and touch can be important for providing the sensory feedback necessary for grasping delicate objects firmly without causing damage to them. Touch can also provide a useful means for discriminating between objects having different sizes, shapes or weights. Accordingly, various tactile sensors have been developed for use with industrial robots.
However, there are problems such as easy wear and tear damage with this sensor for robotic picking and assembly applications that need to be overcome. In this problem, the robotic hand is constantly picking parts and assembling parts which means that the finger/gripper surface is prone to abrasion/wear. This implies that any tactile sensing which employs fragile thin film coatings at grip points can easily wear off. Also, any elaborate light/LED source configuration limits the size of the in-hand object location system. An additional problem is that the size of the light source and sensor are too big to mount on small robotic fingers to pick up small objects. Thus, mounting an elaborate light source for in-hand perception is not feasible. The current state of the art lacks information on object handling/gripping as a part of the robotic hand.
The invention provides an in-hand object location system including at least one robotic hand including a plurality of grippers and a body and at least one camera disposed on a periphery surface of the plurality of grippers. The invention also provides at least one illumination surface disposed on a periphery surface of the plurality of grippers and at least one tactile sensor disposed in the at least one illumination surface. The at least one robotic hand, the plurality of grippers, the at least one camera, the at least one illumination surface and the at least one tactile sensor are electrically connected to a controller.
The invention further provides a robotic hand device including a plurality of grippers and a body and at least one camera disposed on a periphery surface of the plurality of grippers. The invention also provides at least one illumination surface disposed on a periphery surface of the plurality of grippers and at least one tactile sensor disposed in the at least one illumination surface. The at least one robotic hand, the plurality of grippers, the at least one camera, the at least one illumination surface and the at least one tactile sensor are electrically connected to a controller.
The invention also provides a method of in-hand object location including providing at least one robotic hand including a plurality of grippers and a body and providing at least one camera disposed on a periphery surface of the plurality of grippers. The method also includes providing at least one illumination surface disposed on a periphery surface of the plurality of grippers and providing at least one tactile sensor disposed in the at least one illumination surface. The method further includes actuating the plurality of grippers to grasp a workpiece via a controller and illuminating the at least one illumination surface upon grasping the workpiece by the plurality of grippers at a point of contact pressure. The method also includes viewing the position of the workpiece via the at least one camera and comparing the relative position of the workpiece to a position of the at least one robotic hand and a position of the plurality of grippers grasping the workpiece. The method further includes determining the in-hand position of the workpiece and placing the workpiece with the correct orientation in a workspace. The at least one robotic hand, the plurality of grippers, the at least one camera, the at least one illumination surface and the at least one tactile sensor are electrically connected to the controller.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and “at least one” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
In one embodiment, the invention proposes a robot hand/finger surface serving as a light source in itself by using a soft electro-luminescent material or other luminescent material. The novel idea is to use pressure sensitive illumination to replace elaborate light sources. The invention also proposes a grid pattern on the finger surface to perceive deformation in the tactile surface with greater ease. This deformation in grid can be correlated with the force with which a certain object is being held. The deformation in the grid can also show in there is pinching (too much force) or inadequate force which grasping or assembling parts.
Pressure generated illumination is seen in shoes that light up when force in applied, or even capacitive touch based activation where force makes or breaks a contact thereby turning a circuit on or off. Illumination on contact may be achieved by pressure sensitive LED arrays or a form of luminescence activated upon touch/grasp.
An in-hand object location system may be used to determine the location of a part held within a robot hand. This system may additionally provide information about the geometry of the object. This system may also be used to find a different location that may provide a better grasp of the object. Such an in-hand object location system requires a light source and a detector or camera unit within the robot hand. Mounting an elaborate light source while maintaining a compact robot hand/fingers may be challenging. This invention can overcome such a challenge. The invention proposes an illuminated robot hand/finger surface serving as a light source in itself. The idea is to use a pressure-activated glow as a light source in itself. Thus, luminescent films may be coated onto robot hands/fingers in order to serve as the light source for the in-hand object location system.
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Further, the in-hand sensor 40 may include a block of transparent rubber or gel, one face of which is coated with metallic paint. When the paint-coated face is pressed against an object, it conforms to the object's shape. The metallic paint makes the object's surface reflective, so its geometry becomes much easier for computer vision algorithms to infer. Mounted on the sensor opposite the paint-coated face of the rubber block are colored lights/LEDs 50a-d and a single camera 45. This system needs to have colored lights at different angles, and then it has the reflective material, and by looking at the colors, a computer can determine a 3-D shape of what object is being sensed or touched.
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Object location system 70 may also include gripping surfaces 75a, 75b disposed on a surface of grippers 95a, 95b, respectively. Gripping surfaces 75a, 75b include a layer of pressure generated illumination surfaces 85 comprised of pressure sensitive luminescent films. Using an in-hand object location system with pressure sensitive illumination can allow easy perception of the part of an object that has been gripped without the need for an elaborate light source. Illumination surfaces 85 may generate enough light to act as a light source for cameras 80a, 80b to receive better imagery of workpiece 90 as it is manipulated in-hand. In some embodiments, surfaces 85 illuminate upon coming into contact with a workpiece 90 via a pressure-activated glow effect triggered by pressure on workpiece 90. Gripping surfaces 75a, 75b, cameras 80a, 80b and grippers 95a, 95b may be electrically and mechanically connected to a power source and control system 143 (
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It should be appreciated that the features of film surface 105, gripper 95a and camera 110 may be duplicated in an opposing gripper (not shown) to gripper 95a in a similar configuration as that of
It should also be appreciated that the object location system 70, 72 may include a plurality of devices 70, 72 to provide in-hand object location of a plurality of workpiece 90, as needed by a user.
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The various embodiments described herein may provide the benefits of a reduction in the engineering time and cost to design, build, install and tune a special finger, or a special fixture, or a vision system for picking, placing and assembly applications in logistics, warehouse or small part assembly. Also, these embodiments may provide a reduction in cycle time since the robotic hand can detect the position of the in-hand part right after picking the part. Further, these embodiments may provide improved robustness of the system. In other words, with the highly accurate in-hand object location and geometry, the robot can adjust the placement or assembly motion to compensate for any error in the picking. Moreover, these embodiments may be easy to integrate with general purpose robot grippers, such as the robotic YUMI hand, herein incorporated by reference, for a wide range of picking, placing and assembly applications.
The techniques and systems disclosed herein may be implemented as a computer program product for use with a computer system or computerized electronic device. Such implementations may include a series of computer instructions, or logic, fixed either on a tangible/non-transitory medium, such as a computer readable medium 300 (e.g., a diskette, CD-ROM, ROM, flash memory or other memory or fixed disk) or transmittable to a computer system or a device, via a modem or other interface device, such as a communications adapter connected to a network over a medium.
The medium 300 may be either a tangible medium (e.g., optical or analog communications lines) or a medium implemented with wireless techniques (e.g., Wi-Fi, cellular, microwave, infrared or other transmission techniques). The series of computer instructions (e.g.,
Furthermore, such instructions (e.g., at 400) may be stored in any tangible memory device 405, such as semiconductor, magnetic, optical or other memory devices, and may be transmitted using any communications technology, such as optical, infrared, microwave, or other transmission technologies.
It is expected that such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation (e.g., shrink wrapped software), preloaded with a computer system (e.g., on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the network (e.g., the Internet or World Wide Web). Of course, some embodiments of the invention may be implemented as a combination of both software (e.g., a computer program product) and hardware. Still other embodiments of the invention are implemented as entirely hardware, or entirely software (e.g., a computer program product).
As will be apparent to one of ordinary skill in the art from a reading of this disclosure, the present disclosure can be embodied in forms other than those specifically disclosed above. The particular embodiments described above are, therefore, to be considered as illustrative and not restrictive. Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific embodiments described herein. Thus, it will be appreciated that the scope of the present invention is not limited to the above described embodiments, but rather is defined by the appended claims; and that these claims will encompass modifications of and improvements to what has been described.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the description herein. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
