Finger subassembly for robot manipulator

Abstract

The present disclosure relates to a finger subassembly for a gripper assembly of a robotic manipulator, the finger subassembly comprising a base unit connectable to the gripper assembly by a mount and a high friction pad for contacting an article during manipulation of the article, the high friction pad being mechanically fixed to the base unit.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to a finger subassembly for a gripper assembly of the type used with a robotic manipulator.Aspects of the present disclosure relate to a finger subassembly, a gripper assembly, and a robotic manipulator. [Background technology]

[0002] Robotic manipulators often include a gripper having opposing finger subassemblies for gripping an article during its operation. In most cases, the finger subassemblies include one or more high friction pads for contacting the article. The high friction pads are typically secured to a base unit or equivalent by an adhesive. This can cause problems in that the adhesive can degrade over time, leading to separation of the high friction pads, which can be particularly problematic if the finger subassemblies are required to pick food items, as this would require a food-safe adhesive that meets stringent regulatory requirements.

[0003] It is against this background that the present invention was conceived. Summary of the Invention

[0004] Thus, in a first aspect, a finger subassembly for a gripper assembly is provided, the finger subassembly comprising a base unit connectable to the gripper assembly by a mount and a high friction pad for contacting an article during manipulation of the article, the high friction pad being mechanically fixed or engaged to the base unit to prevent relative movement therebetween. Conventional finger subassemblies include a high friction pad fixed to its base unit or equivalent by adhesive. This can cause problems in that the adhesive can deteriorate over time resulting in delamination of the high friction pad, and can be particularly problematic when the gripper assembly is required to pick food products, as this would require a food-safe adhesive that must meet stringent regulatory requirements. The use of adhesive also makes replacement of the high friction pad more difficult. Thus, instead of the chemical bond provided by adhesive, the finger subassembly according to the first aspect is configured such that the high friction pad is mechanically fixed to or engaged with the base unit to prevent relative movement therebetween.

[0005] Optionally, the base unit includes a notch defining a recessed area in which a high friction pad is slidably received.

[0006] Optionally, the notch and the high friction pad are configured to form an interference fit when the high friction pad is inserted.

[0007] Optionally, the high friction pad is oversized laterally relative to the notch.

[0008] Optionally, the high friction pad is oversized relative to the notch in the longitudinal direction.

[0009] Optionally, the width of the notch and high friction pad tapers in a direction towards the tip of the base unit.

[0010] Optionally, the high friction pad comprises a rigid plate overmolded with a high friction material, the base unit further comprising a longitudinal undercut into which a portion of the rigid plate is received when the high friction pad is received in the notch.

[0011] Optionally, an end of the notch at the tip of the base unit includes a lateral undercut into which a portion of the rigid plate is received when the high friction pad is received in the notch.

[0012] Optionally, the thickness of the high friction pad is tapered such that when the high friction pad is received in the notch, a portion of the high friction material and the rigid plate is received in the lateral undercut.

[0013] Optionally, the rigid plate is perforated.

[0014] Optionally, the notch includes an open end into which a high friction pad is received.

[0015] Optionally, the base unit is configured such that when the finger subassembly is connected to the mount, the open end of the notch is at least partially closed by the mount.

[0016] Optionally, the tip of the base unit is shaped to protect the end of the high friction pad from impact during use.

[0017] Optionally, the base unit includes a bore through which a bolt configured to fasten the finger subassembly to the mount can be accessed.

[0018] Optionally, the finger sub-assembly further comprises a frame unit, the frame unit and the base unit configured to be fastened together to clamp the high friction pad in place.

[0019] In a second aspect, there is provided a gripper assembly comprising a finger subassembly according to the first aspect.

[0020] In a third aspect, there is provided a robotic manipulator comprising a gripper assembly according to the second aspect. [Brief description of the drawings]

[0021] These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of a picking system for use in accordance with the present invention. [Diagram 2] FIG. 2 is a side view of a gripper assembly for use with the system of FIG. [Diagram 3] FIG. 3 is an isometric view of the finger subassembly as shown in FIG. [Figure 4a] FIG. 4a is an isometric view of the base unit of the finger subassembly of FIG. [Figure 4b] FIG. 4b is a plan view of the base unit of FIG. 4a. [Figure 5a] FIG. 5a is a top view of the high friction pad of the finger subassembly of FIG. [Figure 5b] FIG. 5b is a side view of the high friction pad of FIG. 5a. [Figure 6] 6 is a side cross-sectional view of the finger subassembly of FIG. [Figure 7] FIG. 7 is a longitudinal cross-sectional view of the finger subassembly of FIG.

[0022] In the drawings, like features are designated by like reference numerals where appropriate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] In the following description, specific details are included to provide a thorough understanding of the disclosed examples. However, those skilled in the art will recognize that other examples may be practiced without one or more of these specific details or with other components, materials, etc., and structural changes may be made without departing from the scope of the present invention as defined in the appended claims. Furthermore, in the following description, references to any terms having an implied orientation are not intended to be limiting, and refer only to the orientation of the features shown in the accompanying drawings. In some instances, well-known features or systems, such as processors, sensors, storage devices, network interfaces, fasteners, electrical connectors, etc., are not shown or described in detail to avoid unnecessarily obscuring the description of the disclosed embodiments.

[0024] Unless the context requires otherwise, throughout this specification and the appended claims, the word "comprise" and variations thereof, such as "comprises" and "comprising," are to be interpreted in their open and inclusive sense, such as "including, but not limited to."

[0025] References throughout this specification to "one," "an," or "another" applied to an "embodiment," "example," or "embodiment" mean that the particular referenced feature, structure, or characteristic described in connection with an embodiment, example, or implementation is included in at least one embodiment or implementation. Thus, the appearances of the phrase "in one embodiment" or the like in various places throughout this specification do not necessarily all refer to the same embodiment. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments, examples, or implementations.

[0026] As used in this specification and the appended claims, the user forms "a," "an," and "the" are intended to include plural referents unless the content clearly dictates otherwise. It should be noted that the term "or" is generally used in its sense to include "and / or" unless expressly specified otherwise.

[0027] With reference to FIG. 1, an example of a picking system 100 of a type suitable for use with the present invention is shown. The picking system 100 may form part of an online retail operation, such as an online grocery retail operation, but may also be applied to any other operation requiring picking and / or sorting of items or objects. In this example, the system 100 includes a manipulator device 102 with a robotic manipulator 121. The robotic manipulator 121 is configured to pick an object 132 from a first location and place the object 132 at a second location. The manipulator device 102 is communicatively coupled via a communication interface 104 to other components of the system 100, such as one or more optional operator interfaces 106, from which an observer may observe or monitor the operation of the system 100 and the manipulator device 102. The operator interface 106 may include a WIMP interface and an output display of a narrative or dynamic representation of the manipulator device 102 in a context or scenario. For example, the dynamic representation of the manipulator device 102 may include video and audio feeds, such as computer-generated animation. Examples of suitable communication interfaces 104 include a wire-based network or communication interface, an optical-based network or communication interface, a wireless network or communication interface, or a combination of wired, optical, and / or wireless network or communication interfaces.

[0028] The system 100 further comprises a control system 108 including at least one controller 110 communicatively coupled to the manipulator device 102 and other components of the system 100 via a communication interface 104. The controller 110 comprises a control unit or computing device having one or more electronic processors embedded therein a set of control instructions provided as processor-executable data that, when executed, cause the controller 110 to issue actuation commands or control signals to the manipulator system 102 and cause the robotic manipulator 121 to perform various operations, such as identifying and manipulating an item 132. The one or more electronic processors may include at least one logic processing unit, such as one or more microprocessors, central processing units (CPUs), digital signal processors (DSPs), graphics processing units (GPUs), application specific integrated circuits (ASICs), programmable gate arrays (PGAs), programmed logic units (PLUs), and the like. In some implementations, the controller 110 is a smaller processor-based device, such as a mobile phone, a single board computer, an embedded computer, etc., which may be interchangeably referred to or as a computer, a server, or an analyzer. A set of control instructions may be provided as processor-executable data associated with the operation of the system 100 and the manipulator apparatus 102 contained in a non-transitory processor-readable storage device 112, which forms part of the system 100 and is accessible to the controller 110 via the communication interface 104. In some implementations, the storage device 112 includes two or more separate devices. The storage device 112 may include, for example, one or more volatile storage devices, such as a random access memory (RAM), and one or more non-volatile storage devices, such as a read-only memory (ROM), a flash memory, a magnetic hard disk (HDD), an optical disk, a solid-state disk (SSD), etc.Those skilled in the art will appreciate that storage may be implemented in a variety of ways, such as read-only memory (ROM), random access memory (RAM), hard disk drive (HDD), network drive, flash memory, digital versatile disk (DVD), any other form of computer and processor readable memory or storage medium, and / or combinations thereof. Storage may be read-only or read / write, as appropriate.

[0029] The system 100 includes a sensor subsystem 114 comprising one or more sensors that detect, sense, or measure a condition or state of the manipulator apparatus 102 and / or a condition of the environment or workspace in which the manipulator 121 operates, and generate or provide corresponding sensor data or information. The sensor information includes environmental sensor information representative of environmental conditions within the workspace of the manipulator 121, as well as information representative of a condition or state of the manipulator apparatus 102, including its various subsystems and components, and characteristics of the item 132 being manipulated. The acquired data can be transmitted to the controller 110 via the communication interface 104 to instruct the manipulator 121 accordingly. Such information can include diagnostic sensor information, for example, useful in diagnosing a state or condition of the manipulator apparatus 102 or the environment in which the manipulator 121 operates. For example, such sensors can include contact sensors, force sensors, strain gauges, vibration sensors, position sensors, orientation sensors, accelerometers, etc. Such sensors may include one or more of a camera or imaging device 116 (e.g., responsive in the visible and / or non-visible ranges of the electromagnetic spectrum, including infrared and ultraviolet), radar, sonar, touch sensors, pressure sensors, load cells, microphones 118, weather sensors, chemical sensors, etc. In some implementations, the diagnostic sensors include sensors for monitoring the status and / or health of an on-board power source (e.g., battery array, ultracapacitor array, fuel cell array) in the manipulator device 102. In some implementations, the one or more sensors comprise a receiver for receiving position and / or orientation information regarding the manipulator 121. For example, a Global Positioning System (GPS) receiver for receiving GPS data, two or more time signals for the controller 110 to create a position measurement based on data in the signal, such as time of flight, signal strength, or other data to achieve a position measurement. Also, for example, one or more accelerometers forming part of the manipulator device 102 may be provided on the manipulator 121 to obtain inertial or orientation data in one, two, or three axes regarding its movement.

[0030] The manipulator 121 may be operated by a human operator at the operator interface 106. In a human operator control or steering mode, the human operator observes a representation of sensor data, e.g., video, audio, or haptic data, received from one or more sensors of the sensor subsystem 114. The human operator then acts conditioned by his perception of the representation of the data and creates information or executable control instructions to guide the manipulator 121 accordingly. In the steering mode, the manipulator device 102 may execute control instructions in real time (e.g., without additional delay) as received from the operator interface 106 based on the sensed information and without consideration of other control instructions.

[0031] In some implementations, the manipulator device 102 operates autonomously, i.e., a human operator does not create control instructions in the operator interface 106 to direct the manipulator 121. The manipulator device 102 may operate in an autonomous control mode by executing autonomous control instructions. For example, the controller 110 can use sensor data from one or more sensors of the sensor subsystem 114, which sensor data is associated with operator-generated control instructions from one or more times that the manipulator device 102 was in a maneuvering mode, to generate autonomous control instructions for subsequent use. For example, by using deep learning techniques to extract features from the sensor data such that in the autonomous mode, the manipulator device 102 autonomously recognizes features or conditions in its environment and the manipulated article 132, and accordingly performs a defined action, set of actions, task, or pipeline or sequence of tasks. In some implementations, the controller 110 autonomously perceives features and / or conditions in the environment surrounding the manipulator 121, as represented by sensor data from the sensor subsystem 114 and one or more virtual objects synthesized into the environment, and issues control signals to the manipulator device 102 to perform one or more actions or tasks in response to the representations being presented.

[0032] In some examples, the manipulator device 102 may be piloted, operated, or controlled by a human operator at some times and autonomously controlled at other times, i.e., operate under an autonomous control mode and change to operate under a piloted (i.e., non-autonomous) mode. In another mode of operation, the manipulator device 102 may replay or execute control instructions previously executed in a human operator controlled (or piloted) mode. That is, the manipulator device 102 may operate without sensor data, based on replayed pilot data.

[0033] The manipulator apparatus 102 further includes a communication interface subsystem 124, e.g., a network interface device communicatively coupled to the bus 126 and providing bidirectional communication with other components of the system 100 (e.g., the controller 110) via the communication interface 104. The communication interface subsystem 124 may be any circuitry that affects the bidirectional communication of processor-readable data and processor-executable instructions, such as a radio (e.g., a radio or microwave frequency transmitter, receiver, transceiver), a communication port, and / or an associated controller. Suitable communication protocols include FTP, HTTP, Web Services, SOAP with XML, WI-FI® compliant, BLUETOOTH® compliant, cellular (e.g., GSM®, CDMA), and the like.

[0034] The manipulator 121 is an electromechanical machine that includes one or more appendages, such as a robotic arm 120, and a gripper assembly or end effector 122 attached to the end of the robotic arm 120. The gripper assembly 122 is a device of complex design configured to interact with an environment to perform several tasks, including, for example, grasping, holding, releasably engaging, or otherwise interacting with an item 132. The manipulator apparatus 102 further includes a motion subsystem 130 communicatively coupled to the robotic arm 120 and the gripper assembly 122. The motion subsystem 130 includes one or more motors, solenoids, other actuators, linkages, drive belts, etc. operable to move the robotic arm 120 and / or the gripper assembly 122 through a range of motion according to actuation commands or control signals issued by the controller 110. The motion subsystem 130 is communicatively coupled to the controller 110 via a bus 126.

[0035] The manipulator device 102 also includes an output subsystem 128 that includes one or more output devices, such as a speaker, light, or display, that enable the manipulator device 102 to transmit signals into the workspace, for example, to communicate with an operator and / or another manipulator device 102.

[0036] Those skilled in the art will understand that components of manipulator device 102 may be altered, combined, divided, omitted, etc. In some examples, one or more of communication interface subsystem 124, output subsystem 128, and / or motion subsystem 130 may be combined. In other examples, one or more of the subsystems (e.g., kinematic subsystem 130) are divided into additional subsystems.

[0037] Figure 2 shows an example of a gripper assembly 122 suitable for use with the manipulator 121 of Figure 1. In this example, the gripper assembly 122 includes a wrist component 134 that is used to connect the assembly 122 to the manipulator 121. The wrist component 134 movably supports a link assembly, generally designated 136. The link assembly 136 includes two pairs of link arms 138a, 138b that are driven by an actuator housed within the wrist component 134. Each pair of link arms 138a, 138b are connected at their distal ends by a mount 140, which carries a finger subassembly 142.

[0038] Referring to FIG. 3, the finger subassembly 142 comprises a base unit 144 connectable to the gripper assembly 122 by a mount 140, and a high friction pad 146 defining a contact surface 147 for an article during manipulation of the article. In conventional finger subassemblies, the high friction pad is secured to its base unit or equivalent by adhesive. This can cause problems in that the adhesive can deteriorate over time, leading to separation of the high friction pad, which can be particularly problematic if the gripper assembly 122 is required to pick food products, which would require a food-safe adhesive that must meet strict regulatory requirements. The use of adhesive also makes replacement of the high friction pad more difficult. Therefore, instead of adhesive, the finger subassembly 142 of the present invention is configured such that the high friction pad 146 is mechanically secured to or engaged with the base unit 144, as opposed to the chemical bond provided by an adhesive, preventing relative movement therebetween. In one example, the finger subassembly 142 may include a frame unit that may be fastened to the base unit 144 to clamp the high friction pad 146 in place. In the example shown in FIG. 3, the base unit 144 includes a notch 148 that defines a recessed area 150 in which the high friction pad 146 is received. In this example, the notch 148 and the high friction pad 146 are configured to allow the high friction pad 146 to be slidably received in the recessed area 150. This configuration avoids the use of adhesives and provides an easy method for removing and replacing the high friction pad 146 as needed.

[0039] 4a, 4b, 5a, and 5b, to facilitate insertion and removal of the high friction pad 146, the width of the notch 148 tapers in a direction along the major or longitudinal axis of the base unit 144 toward the tip 152 of the base unit 144, and the high friction pad 146 is similarly tapered to define a complementary shape.

[0040] In this example, the high friction pad 146 comprises a substantially rigid plate 154 overmolded with a high friction compressible material 156, such as silicone. The rigid plate 154 may be made of a metal, such as aluminum, and includes a plurality of perforations 157 to facilitate the overmolding process by allowing the liquefied high friction material 156 to flow to both sides of the rigid plate 154. The area in which the high friction material 156 is formed is smaller than the area of ​​the rigid plate 154, leaving exposed rims 158 extending along each longitudinal side of the high friction pad 146. These rims 158 are configured to be received within longitudinal undercuts 160 formed in the sides of the notches 148 when the high friction pad 146 is received in the recessed area 150, precisely locating the high friction pad 146 within the notches 148 and further facilitating insertion and removal of the high friction pad 146.

[0041] In general, the notch 148 and the high friction pad 146 are configured to form an interference or press-fit joint when the high friction pad 146 is placed in the notch 148, providing a frictional connection that holds the high friction pad 146 in place relative to the notch 148. To that end, for the present example of the finger subassembly 142, the high friction pad 146 is oversized in both the lateral and longitudinal directions compared to the notch 148, as shown in Figures 6 and 7, respectively, meaning that the high friction pad 146 is under compression when held in the notch 148. Referring to Figure 7, the thickness of the high friction pad 146 tapers or decreases toward its end 162 positioned by the tip 152 of the base unit 144, defining a curved contact surface 147 in that region of the high friction pad 146. This tapered end 162 includes a portion of the rigid plate 154 and is received in a lateral undercut 164 formed at the end of the notch 148. This compresses the high friction material 156 in the lateral undercut 164, forming an interference or press-fit joint near the tip 152 of the base unit 144. The tip 152 is spherical or rounded to protect this joint from shocks during use. The other end 166 of the high friction pad 146 seats in the open end 168 of the notch 148. As shown in FIG. 4a, the open end 168 is at least partially closed by the mount 140 when the mount 140 is fastened to the finger subassembly 142. The base unit 144 includes a bore 170 through which a bolt configured to fasten the finger subassembly 142 to the mount 140 can be easily accessed. In this regard, the mount 140 functions to hold the high friction pad 146 in place by applying a compressive force. These configurations, with a tight fitting connection between the high friction pads 146 and the notches 148, ensure that the joints formed therebetween are slight and of minimal depth and width, which reduces the area on the finger subassembly 122 where dirt and bacteria can accumulate, an important consideration, especially when the gripper assembly 122 must pick up food items.

[0042] The foregoing description has been presented for purposes of illustration only, and is not intended to be exhaustive or to limit the invention to the precise form disclosed. It will be understood that modifications and variations can be made to the described embodiments without departing from the scope of the invention, which is defined in the appended claims.

Claims

1. 1. A finger subassembly for a gripper assembly, comprising: a base unit connectable to the gripper assembly by a mount; and a high friction pad for contacting an article during manipulation of the article, wherein said high friction pad is mechanically secured to said base unit to prevent relative movement therebetween.

2. The finger subassembly of claim 1 , wherein the base unit includes a notch defining a recessed area in which the high friction pad is received.

3. The finger subassembly of claim 2 , wherein the notch and the high friction pad are configured to form an interference fit when the high friction pad is received therein.

4. The finger subassembly of claim 3 , wherein the high friction pad is laterally oversized relative to the notch.

5. The finger subassembly of claim 3 or 4, wherein the high friction pad is longitudinally oversized relative to the notch.

6. The finger subassembly of claim 3 , wherein a width of the notch and the high friction pad tapers in a direction toward a tip of the base unit.

7. 7. The finger subassembly of claim 2, wherein the high friction pad comprises a rigid plate overmolded with a high friction material, and the base unit further comprises a longitudinal undercut into which a portion of the rigid plate is received when the high friction pad is received in the notch.

8. 8. The finger subassembly of claim 7, wherein an end of the notch at the distal end of the base unit includes a lateral undercut into which a portion of the rigid plate is received when the high friction pad is received in the notch.

9. 9. The finger subassembly of claim 8, wherein a thickness of the high friction pad is tapered such that when the high friction pad is received in the notch, the high friction material and a portion of the rigid plate are received in the lateral undercut.

10. The finger subassembly of claim 7 , wherein the rigid plate is perforated.

11. The finger subassembly of claim 2 , wherein the notch includes an open end into which the high friction pad is received.

12. The finger subassembly of claim 11 , wherein the base unit is configured such that an open end of the notch is at least partially closed by the mount when the finger subassembly is connected to the mount.

13. 13. A finger subassembly according to any one of claims 1 to 12, wherein the tip of the base unit is shaped to protect the end of the high friction pad from impact during use.

14. The finger subassembly of claim 1 , wherein the base unit comprises a bore through which a bolt configured to fasten the finger subassembly to the mount can be accessed.

15. The finger subassembly of claim 1 , further comprising a frame unit, said frame unit and said base unit configured to be fastened together to clamp said high friction pad in place.

16. A gripper assembly comprising a finger subassembly according to any one of claims 1 to 15.

17. A robotic manipulator comprising the gripper assembly of claim 16.

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