Gripping device modalities
Robotic gripping devices and methods for performing a picking operation. The methods described herein may involve positioning a gripping device with respect to an item to be grasped and then executing a first picking operation using the gripping device to obtain a grasp on the item. The methods may then involve executing at least two of a force detection procedure to detect a force applied to a portion of the gripping device, a grasping space detection procedure to detect an item in grasping range of the gripping device, a pressure detection procedure configured to detect pressure in an airflow path, and an item load detection procedure to detect force in a mechanical load path of the gripping device.
1 . A system for performing a picking operation, the system comprising:
a gripping device configured to execute a first picking operation to obtain a grasp on an item;
a control module;
a force detection modality configured to provide a first data output indicative of a detected force applied to a portion of the gripping device,
a grasping space modality configured to provide a second data output indicative of a detected item in grasping range of the gripping device,
a pressure detection modality configured to provide a third data output indicative of a detected pressure in an airflow path, and
an item load detection modality configured to provide a fourth data output indicative of a detected force in a mechanical load path of the gripping device;
wherein the control module is configured to:
receive the first data output, second data output, third data output, and fourth data output; and
determine that the gripping device did not grasp the item based on the second data output indicating a positive classification and the first data output, third data output, and fourth data output indicating negative classifications.
2 . The system of claim 1 wherein the gripping device is further configured to execute a second picking operation to obtain a grasp on the item upon the control module determining the first picking operation did not obtain a grasp on the item.
3 . The system of claim 2 wherein the system is configured to operably position the gripping device at a place location upon the control module determining the second picking operation did obtain a grasp on the item, and wherein the gripping device is further configured to place the item at the place location.
4 . The system of claim 1 wherein the gripping device includes at least one finger portion, and the force detection modality is configured to detect a force applied to the at least one finger portion.
5 . The system of claim 1 wherein the first data output relates to a force generated by a portion of the gripping device gathered by the force detection modality by measuring at least one of air pressure, motor torque, series elastic deflection, servo tracking error, and rotational position of at least one finger portion.
6 . The system of claim 1 wherein the control module is configured to instruct the gripping device to execute a second picking operation upon:
at least two of the first, second, third, or fourth data output indicating that the gripping device grasped the item, and
one of the first, second, third, or fourth data outputs indicating that the gripping device did not grasp the item.
7 . The system of claim 1 wherein the pressure detection modality includes a pressure sensor embedded in a structure of the gripping device to detect a suction force from a suction device, and the item load detection modality includes a strain gauge operably positioned within the structure to detect a load force resultant from lifting the item.
8 . The system of claim 1 wherein:
the force detection modality includes at least one finger portion configured to grasp the item, and
the grasping space modality includes at least one range-based sensor that is each operably mounted on the gripping device to view a grasping space, and
wherein the at least one finger portion and the at least one range-based sensor are operably positioned so that the finger portion does not interfere with the view of the grasping space.
9 . The system of claim 8 wherein the range-based sensor is operably positioned within a palm of the gripping device.
10 . The system of claim 9 wherein the force detection modality includes at least one finger portion configured to grasp the item, the finger portion including:
a first segment configured with a Hall Effect sensor,
a second segment configured with a magnet, and
a bend point operably positioned between the first segment and the second segment, wherein the first data output is indicative of whether the finger portion has grasped an item and based on a distance between the magnet of the second segment and the Hall effect sensor of the first segment.
11 . The system of claim 1 further comprising sensors configured with the gripping device.
12 . A method for performing a picking operation, the method comprising:
positioning a gripping device with respect to an item to be grasped;
executing a first picking operation using the gripping device to obtain a grasp on the item;
executing, to determine whether the gripping device has obtained a grasp on the item, a plurality of procedures, the plurality of procedures including:
a force detection procedure to provide a first data output indicative of a detected force applied to a portion of the gripping device,
a grasping space detection procedure to provide a second data output indicative of a detected item in grasping range of the gripping device,
a pressure detection procedure to provide a third data output indicative of a detected pressure in an airflow path, and
an item load detection procedure to provide a fourth data output indicative of a detected force in a mechanical load path of the gripping device;
receiving the first data output, second data output, third data output, and fourth data output; and
determining that the gripping device did not grasp the item based on the second data output indicating a positive classification and the first data output, third data output, and fourth data output indicating negative classifications.
13 . The method of claim 12 further comprising executing a second picking operation to obtain a grasp on the item upon determining the first picking operation did not obtain a grasp on the item.
14 . The method of claim 13 further comprising:
operably positioning the gripping device at a place location upon determining the first picking operation did obtain a grasp on the item based, and
placing the item at the place location.
15 . The method of claim 12 wherein the gripping device includes at least one finger portion, and executing the force detection procedure includes measuring at least one of current draw, torque output, air pressure, air flow rate, and rotational position of at least one finger portion.
16 . The method of claim 13 further comprising:
receiving at least two of the first, second, third, or fourth data output indicating that the item has been grasped;
receiving one of the first, second, third, or fourth data output indicating that the item has not been grasped; and
executing a second picking operation.
17 . The method of claim 12 wherein executing the pressure detection procedure includes detecting a suction force in a structure operably connected to a suction device, and executing the item load detection procedure includes detecting a load force resultant from lifting the item.
18 . The method of claim 12 wherein one of the at least two procedures is the force detection procedure, and the gripping device includes at least one finger portion including:
a first segment configured with a Hall Effect sensor,
a second segment configured with a magnet, and
a bend point operably positioned between the first segment and the second segment, wherein the first output signal is of whether the finger portion has grasped an item and is based on a distance between the magnet of the second segment and the Hall effect sensor of the first segment.
19 . The method of claim 12 further comprising determining that the first picking operation was successful upon at least two of the first, second, third, or fourth data output indicating picking operation was successful.