Patent Application
20230311340
This invention relates generally to handling a dish with an end effector attached to a robotic arm.
Picking up, holding and dropping off dishes of different shapes and sizes may appear as routine unremarkable tasks for people. In reality, handling dishes is a complex activity that is uniquely made possible by the remarkable dexterity of human hands.
Our hands can adapt in form based on the dish they need to handle. For instance, the shape of our hand when it is holding a dinner plate is different from the shape of our hand when it is holding a coffee mug. Our hands can also adapt in function based on the actions we desire to perform. For instance, the sequence of actions our hand performs while picking up a spoon is distinct from the sequence of actions it performs while dropping off a bowl. Furthermore, our hands can make corrections for potential failures. For instance, when a glass cup is about to slip away, our hands sense imminent danger and perform one or more actions to get back to a stable grip.
Handling dishes is also complicated by the fact that we prefer to stack dishes on each other to maximize space efficiency. But stacking is not a big deal for our hands to handle, as their dexterity allows them to easily separate a dish from a bunch of its collocated clones. Furthermore, our preference for storing dishes inside cabinets of modular kitchens adds an additional layer of complexity as dishes are not readily accessible. This again is not an obstacle for our hands as they can pull and push cabinets with ease.
Conventional robots, however, are no match for human hands due to the limited dexterity of their end effectors. For instance, mechanical grippers and vacuum suction cups are unable to adapt to the needs for handling a variety of dish types. The differences between a spoon and a dinner plate are too overwhelming for these conventional end effectors to deal with. Such conventional end effectors are best suited for moving an independent object of a single type in an otherwise open unobstructed environment.
Accordingly, there is a need for an improved system and method to pick up, handle and drop off a dish. One that could pick up, hold, and drop off a variety of dish types; one that could pick up, hold, and drop off a stacked dish; one that could pick up, hold, and drop off a dish deep inside one of many cabinets which may be vertically or horizontally arranged, or otherwise in close proximity.
The invention is a system and method for handling a dish with an end effector attached to a robotic arm.
In some embodiments, the invention is a system for handling an article, comprising: a first finger having a belt to make contact with said article; a first actuator configured to move said belt; a second finger surrounding said article; a second actuator to vary the distance between said first finger and said second finger; a processor executing an algorithm to control said first actuator to move said article, and to control said second actuator to hold said article; whereby said article is grasped by moving it to a position between said first finger and said second finger.
A method for handling an article, comprising: opening a first finger and a second finger such that they are not in contact with each other, wherein said first finger comprises a belt configured to move said article; positioning and orienting said first finger and said second finger such that said article is in between the tip of said fingers; closing said first finger and said second finger such that the tip of said fingers are in contact with said article; moving said belt to pull said article from the tip of said fingers to a position deeper inside said fingers, whereby said article is grasped by moving it to a position between said first finger and said second finger.
In some embodiments, fingers 6 and 7 of the end effector has rollers 12, 13 to grasp and manipulate dishes. In some embodiments, a roller is driven by a motor. In other embodiments, a roller is not actively driven by a motor. In some embodiments, fingers 6 and 7 of the end effector have multiple sets of rollers. In some embodiments, both fingers 6 and 7 also comprise a belt actuated by rollers to move a dish. In other embodiments, at least one finger comprises a belt actuated by rollers to move a dish. In some embodiments, not all fingers comprise a belt actuated by rollers to move a dish. In some embodiments, belts attached to fingers 6 and 7 move in the same direction. In other embodiments, belts attached to fingers 6 and 7 move in different directions. In other embodiments, belts attached to fingers 6 and 7 move in orthogonal directions. In other embodiments, a belt attached to a finger moves to reposition the dish to a different position between fingers 6 and 7.
In some embodiments, rollers 12, 13 with motors are placed proximally. In other embodiments, rollers 12, 13 without the motors are placed distally. In some embodiments, a roller without motors uses bearings to reduce the friction and enable them to roll freely around a roller rod 16. In some embodiments, rollers are mounted on both fingers 6 and 7. The fingers 6 and 7 are attached to the gripper base 1.
In some embodiments, rollers 12 and 13 are connected by a belt 14. The belt is driven by roller 12, which is actuated by a shaft 15 attached to a motor. Since the belt connects to a passive roller 13, any motion of the belt also moves roller 13.
In some embodiments, the belt 14 connecting the two rollers 12, 13 can be made of materials such as silicone, rubber, PVC, and polyurethane. In some embodiments, belt 14 is made of one or more elastic materials. In other embodiments, belt 14 is made of one of more non-elastic materials. In some embodiments, the belt exhibits high friction when in contact with dishes.
In some embodiments, fingers 6 and 7 of the end effector are separated from each other by a distance that is greater than the thickness of a dish.
In some embodiments, belt 14 in fingers 6 and 7 of the end effector has at least one sensor to measure the quality of grasp. In other embodiments, the sensors can measure the pressure exerted by the dish onto the belt of the fingers of the end effector. In some embodiments, a finger comprises at least one roller to sense grasp quality. In some embodiments, the end effector comprises a plurality of sensors to sense pressure exerted on a plurality of regions of a dish. In some embodiments, the pressure data from a sensor is used to grasp a dish securely while not damaging it. In some embodiments, pressure data from a sensor is used to determine if fingers 6 and 7 are in contact with a dish. In some embodiments, pressure data from a sensor is used to determine if fingers 6 and 7 are in contact with each other.
In some embodiments, position and orientation of a dish is perceived to facilitate positioning and orienting finger 6 and finger 7 such that a dish is in between the tip of the fingers.
It will be recognized by those skilled in the art that various modifications may be made to the illustrated and other embodiments of the invention described above, without departing from the broad inventive scope thereof. It will be understood therefore that the invention is not limited to the particular embodiments or arrangements disclosed, but is rather intended to cover any changes, adaptations or modifications which are within the scope and spirit of the invention as defined by the appended claims.
It should be understood that the present invention as described above can be implemented in the form of control logic using computer software in a modular or integrated manner. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will know and appreciate other ways and/or methods to implement the present invention using hardware and a combination of hardware and software.
Any of the software components or functions described above, may be implemented as software code to be executed by a processor using any suitable computer language such as, for example, Python, Java, C++ or Perl using, for example, conventional or object-oriented techniques. The software code may be stored as a series of instructions, or commands on a computer readable medium, such as a random access memory (RAM), a read only memory (ROM), a storage device such as a solid state drive (SSD) or a hard drive. Any such computer readable medium may reside on or within a single computational apparatus, and may be present on or within different computational apparatuses within a system or network.
In the claims, reference to an element in the singular is not intended to mean “one and only one” unless explicitly stated, but rather is meant to mean “one or more.” In addition, it is not necessary for a device or method to address every problem that is solvable by different embodiments of the invention in order to be encompassed by the claims.
The above description is illustrative and is not restrictive. Many variations of the disclosure will become apparent to those skilled in the art upon review of the disclosure. The scope of the disclosure should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the pending claims along with their full scope or equivalents.
One or more features from any embodiment may be combined with one or more features of any other embodiment without departing from the scope of the disclosure. Further, modifications, additions, or omissions may be made to any embodiment without departing from the scope of the disclosure. The components of any embodiment may be integrated or separated according to particular needs without departing from the scope of the disclosure.
One or more features from any embodiment may be combined with one or more features of any other embodiment without departing from the scope of the disclosure. Further, modifications, additions, or omissions may be made to any embodiment without departing from the scope of the disclosure. The components of any embodiment may be integrated or separated according to particular needs without departing from the scope of the disclosure.
