CA3033124A1 - Gripper, system and process for gripping, orienting and handling a biological horticultural object - Google Patents

Abstract

A gripper has a mounting bracket, opposed rotatable gripper heads mounted on the bracket, a translation actuator configured to translate at least one of the gripper heads along a gripper head rotation axis to grip a horticultural object between the gripper heads, a drive shaft configured to rotate the object, at least one rotation actuator configured to rotate at least one of the gripper heads to rotate the object between the gripper heads, and the at least one rotation actuator configured to rotate the drive shaft. The gripper heads are rotatable about a common gripper head rotation axis. The drive shaft is configured to rotate the object about a second rotation axis orthogonal to the gripper head rotation axis, the second rotation axis passing between the gripper heads. The gripper is useful in systems and processes for handling solid three-dimensional biological horticultural objects.

Description

GRIPPER, SYSTEM AND PROCESS FOR GRIPPING, ORIENTING AND HANDLING A
BIOLOGICAL HORTICULTURAL OBJECT
Cross-reference to Related Applications This application claims the benefit of United States Provisional Patent Application USSN 62/501,000 filed May 3, 2017, the entire contents of which is herein incorporated by reference.
Field This application relates to horticulture. In particular, this application relates to a gripper, system and process for gripping, orienting and handling a solid three-dimensional biological horticultural object.
Background Greenhouses plant millions of bulbs each year to produce cut and potted flowers.
During the planting process flower bulbs are dumped onto conveyors in bulk before workers pick, orient and place each one with its roots down in a growing medium. Bulbs used for flower production are typically grown in regular arrays (e.g. in rectangular plastic crates, in hydroponic trays, on spikes, etc.) arranged neatly to maximize the usage of greenhouse space. Aligning each bulb properly promotes an even rate of growth and ensures that the resulting flowers are approximately equal in height at harvest time. The wholesale price of flowers is based on their length so consistent quality (i.e. height) is very important to growers.
The planting process is manually intensive; no automated solutions have been adopted by growers. Workers can plant approximately 3000 bulbs per hour per person.
This high throughput is one of the primary challenges to automation. Another challenge is the large variation in size and shape of flower bulbs. These variations can be significant within the same species, let alone between different species, which makes handling and alignment difficult. The bulbs are also very sensitive to shock and vibration once they start to grow, preventing the use of many mechanical orientation techniques, such as vibratory hoppers.
There remains a need for an automated handling system for solid three-dimensional biological horticultural objects, which automatically orients and places such objects in a desired area, for example automatically orients and plants flower bulbs.

Summary In one aspect, there is provided a gripper for gripping and re-orienting a solid three-dimensional biological horticultural object, the gripper comprising: a mounting bracket;
opposed first and second rotatable gripper heads rotatably mounted on the mounting bracket, the opposed first and second rotatable gripper heads rotatable about a common gripper head rotation axis; a translation actuator configured to translate at least one of the opposed rotatable gripper heads along the gripper head rotation axis to grip a solid three-dimensional biological horticultural object between the opposed first and second rotatable gripper heads; a drive shaft configured to rotate the object about a second rotation axis substantially orthogonal to the gripper head rotation axis, the second rotation axis passing between the opposed first and second rotatable gripper heads; and, at least one rotation actuator, the at least one rotation actuator configured to rotate the drive shaft to thereby rotate the object, and the at least one rotation actuator configured to rotate at least one of the opposed rotatable gripper heads to thereby rotate the object gripped between the opposed first and second rotatable gripper heads.
In another aspect, there is provided a gripper for gripping and re-orienting a solid three-dimensional biological horticultural object, the gripper comprising: a mounting bracket; opposed first and second rotatable gripper heads rotatably mounted on the mounting bracket, the opposed first and second rotatable gripper heads rotatable about a common gripper head rotation axis; a translation actuator configured to translate at least one of the opposed rotatable gripper heads along the gripper head rotation axis to grip a solid three-dimensional biological horticultural object between the opposed first and second rotatable gripper heads; a drive shaft connected to the mounting bracket, the drive shaft configured to rotate the mounting bracket about a mounting bracket rotation axis, the mounting bracket rotation axis substantially orthogonal to the gripper head rotation axis, the mounting bracket rotation axis passing between the opposed first and second rotatable gripper heads; and, at least one rotation actuator, the at least one rotation actuator configured to rotate at least one of the opposed rotatable gripper heads to thereby rotate the object gripped between the opposed first and second rotatable gripper heads, and the at least one rotation actuator configured to rotate the drive shaft to thereby rotate the mounting bracket.
In one embodiment, the drive shaft may be mounted on a first side of the mounting bracket, the translation actuator may be mounted on a second side of the mounting bracket opposed to the first side along the mounting bracket rotation axis, and the opposed first and second rotatable gripper heads may be rotatably mounted on first and second opposed

2 flanges, respectively, the first and second opposed flanges mounted on opposed translatable elements of the translation actuator, whereby movement of the opposed translatable elements causes the opposed flanges to move toward or away from each other thereby translating the opposed rotatable gripper heads along the gripper head rotation axis.
In one embodiment, the drive shaft may be connected to a third gripper head and the drive shaft may be configured to rotate the third gripper head about the second rotation axis. The drive shaft may pass through the mounting bracket and may be rotatable without rotating the mounting bracket. The third gripper head may be translatable along the second rotation axis, for example by translating the drive shaft along the second rotation axis. The third gripper head may be deployed to grip the object and then translate the object along the second rotation axis to be positioned on the gripper head rotation axis for gripping by the rotatable gripper heads or for releasing into a storage area. Translation of the third gripper head may be accomplished without moving the mounting bracket. Rotation of the third gripper head about the second rotation axis may also orient the object into a desired orientation before being gripped by the rotatable gripper heads. The third gripper head may be a jamming gripper head, a suction cup, a pincer or the like. Jamming gripper heads are particularly useful for irregularly shaped objects.
In some embodiment, the second rotation axis and the gripper head rotation axis are the only rotation axes on the gripper. The at least one rotation actuator may comprise a first rotation actuator configured to rotate the at least one of the opposed rotatable gripper heads, and a second rotation actuator configured to rotate the drive shaft.
The rotation actuators may comprise motors, for example electric, hydraulic or pneumatic motors or the like. Belts, drive wheels, chains, sprockets, gears or other elements useful in connecting the rotation actuators to the drive shaft and/or gripper heads may be employed.
In some embodiments, the mounting bracket may comprise a horizontally oriented plate. The drive shaft may extend substantially vertically upwardly from the horizontally oriented plate, for example from an upper surface of the horizontally oriented plate, and preferably from a center of the plate. In such a configuration, the second rotation axis may be a vertical axis. In one embodiment, rotation of the drive shaft about the second rotation axis rotates the plate about the mounting bracket rotation axis (i.e. in a horizontal plane when the mounting bracket rotation axis is a vertical axis). In another embodiment, the drive shaft passes through the plate and rotation of the drive shaft does not rotate the plate.

3

4 The opposed first and second rotatable gripper heads rotatably mounted on the mounting bracket may be connected to and situated below the plate. The opposed gripper heads rotate about a common gripper head rotation axis substantially orthogonal to the second rotation axis. When the second rotation axis is a vertical axis, the gripper head rotation axis is a horizontal axis. The second rotation axis may or may not intersect the gripper head rotation axis. Preferably, the second rotation axis intersects the gripper head rotation axis. Preferably, the opposed gripper heads are mounted below the plate such that the second rotation axis and the gripper head rotation axis intersect at an intersection point below the plate. With the drive shaft centrally located on or through the upper surface of the plate, the opposed gripper heads are symmetrically disposed along the gripper head rotation axis on either side of the intersection point. When the two rotation axes intersect, calculation of the rotation between the initial random orientation of the object and the predetermined orientation is simplified. Additionally, physical size of the gripper is reduced.
At least one of the opposed gripper heads is translatable along the gripper head rotation axis to permit gripping of the object between the opposed gripper heads.
Preferably, both of the opposed gripper heads are translatable, preferably translatable in concert. Each of the opposed gripper heads preferably translate toward the intersection point of the two rotational axes when being translated for gripping, and away from the intersection point when being translated for releasing the object. The opposed gripper heads may be mounted on at least one translation actuator, which is configured to translate the opposed gripper heads. The translation actuator preferably comprises a single actuator that can simultaneously translate both gripper heads along the gripper head rotation axis.
The translation actuator may be pneumatic, hydraulic, electric or any other suitable type of actuator. The translation actuator may be mounted on to an underside or on top of the horizontally oriented plate. The opposed gripper heads may be mounted on movable elements of the translation actuator such that extension and retraction of the movable elements effect translation of the opposed gripper heads. Preferably, the opposed gripper heads are mounted on flanges, the flanges mounted on the moveable elements of the translation actuator. The flanges may extend away from the translation actuator parallel to the second rotation axis so that the opposed gripper heads are located below the horizontally oriented plate, and below the translation actuator, by a distance sufficient to accommodate a size of the object to be gripped between the opposed gripper heads.
The opposed gripper heads are both rotatable about the gripper head rotation axis and translatable along the gripper head rotation axis. Preferably, the opposed gripper heads comprise shafts through which the gripper head rotation axis passes. The shafts may be mounted in bearings that permit rotation of the shafts within the bearings and translation of the shafts through the bearings. The shafts may be further housed in housings, whereby the shafts and housings are machined with matching features such as flat faces, keys or the like so that driving rotation of at least one of the housings causes rotation of the shaft in the at least one housing while permitting sliding motion of the shaft in the housing while still transmitting torque and rotation. The housings around the shafts of both opposed gripper heads may be driven, or one of the housings may be idle, allowing rotational forces transmitted through a gripped object to the idle opposed gripper head to rotate the idle opposed gripper head.
The opposed gripper heads preferably possess a degree of compliancy along the gripper head rotation axis to provide an ability to handle objects with some size variation, and to reduce or eliminate damage to the object due to over-gripping.
Compliancy in the opposed gripper heads permits the use of a less accurate, and therefore less expensive, translation actuator. Preferably, the opposed gripper heads comprise flexible fingertips, springs or both flexible fingertips and springs to provide compliancy, although other ways of providing compliancy may be provided. Flexible fingertips may be made of a deformable material, for example an elastomer or a thermoplastic. The flexible fingertips may be compressible along the gripper head rotation axis. The fingertips may be mounted on spring-loaded shafts, springs on the spring-loaded shafts abutting stops to provide resiliency along the gripper head rotation axis by biasing at least one of the opposed gripper heads along the gripper head rotation axis. Any type of springs may be employed (e.g.
helical springs, leaf springs, and the like). The flexible fingertips may conform around a surface of the object, and the spring-loaded shafts may compress to further compensate for larger variations in object size and to prevent or minimize crushing the object when gripped.
Advantageously, the gripper only requires two axes of rotation having full 360 ranges of motion to handle all random object orientations and properly re-orient the object around the object's own center of gravity (or approximate center of gravity) in two independent angular directions, which is simpler and less expensive to manufacture than typical 6-axis robotic grippers. By rotating the gripper about the second rotation axis before gripping the object, then rotating the gripper heads about the gripper head rotation axis after the object has been gripped, and finally rotating the gripper once again about the second rotation axis before releasing the object, any object randomly oriented in three orthogonal directions may be re-oriented into any specified orientation, without relying on .. any assumptions of the object's physical shape or dynamic behavior.

5 In embodiments utilizing the third gripper head, the object may be first gripped by the third gripper head and rotated without rotating the entire gripper before being gripped by the opposed gripper heads. Once gripped by the opposed gripper heads, the object may be rotated into the desired orientation. Again, any object randomly oriented in three orthogonal directions may be re-oriented into any specified orientation, without relying on any assumptions of the object's physical shape or dynamic behavior. The use of the third gripper head permits reduction in the physical space occupied by the entire gripper, which facilitates placing objects closer together in the storage area when an array of grippers is being used. The ability to translate the third gripper head along the second rotation axis also facilitates placing the objects directly in a tightly packed storage area without employing an intermediate staging area for the objects.
Further, the gripper is modular, therefore multiple instances of the gripper may be used in an array to handle multiple objects in parallel leading to greater throughput.
Furthermore, the gripper is robust in handling non-uniform objects, i.e.
objects that exhibit relatively large and uncontrolled variations in size and shape. The simplicity, modularity, robustness and low cost lend to utilizing a plurality of the grippers in a process line to provide a handling process that is more efficient with higher throughputs than existing prior art processes for handling solid three-dimensional biological horticultural objects having uncontrolled variations in size and shape.
In another aspect, there is provided a gripping system for gripping and re-orienting a solid three-dimensional biological horticultural object, the gripping system comprising: at least one gripper as defined above; a visioning device configured to capture information about a randomly-oriented solid three-dimensional biological horticultural object to be gripped and re-oriented; and, a controller operably linked to the gripper and the visioning device, the controller programmed to position and orient the gripper in a first configuration suitable for gripping the randomly-oriented object based on the information about the object captured by the visioning system, operate the gripper to grip the randomly-oriented object between the opposed first and second gripper heads of the gripper, and operate the gripper to rotate the gripped object from the random orientation into a predetermined orientation, the predetermined orientation based on predetermined parameters for suitably orienting the object for further processing.
The system may comprise a variety of components including, for example, one or more grippers, one or more visioning devices (e.g. cameras or line scanners), a controller operatively linked to the one or more grippers and the one or more grippers.
The controller may be configured to operate the one or more grippers to grip and rotate randomly-oriented

6 objects based on information collected by the one or more visioning devices.
One or more sensors (e.g. laser sensors) in electronic communication with the controller may be used to assist in locating the objects.
The system may further comprise one or more of a user interface for the controller, an electrical supply, a conveyor configured to receive and singulate a plurality of the randomly-oriented objects, a holding area for re-oriented objects and at least one automated device (e.g. a robotic arm, a linear actuator or a Cartesian gantry mechanism) for translating the one or more grippers through space to be able to deposit the re-oriented objects in the holding area. Objects singulated on the conveyor at a constant spacing may pass through a field of view of the visioning device. The one or more grippers may comprise a plurality of grippers longitudinally separated along the conveyor by the constant spacing, each of the plurality of grippers operated by the controller to grip a corresponding singulated object on the conveyor.
Control software for controlling aspects of the system may be embodied in the controller. Electronic communication may be provided through wires or wirelessly. The controller may comprise, for example, a computer, an output device and an input device, the computer comprising a microprocessor for controlling operations and a non-transient electronic storage medium for storing information about the objects, the conveyor and the one or more grippers, and/or for storing computer executable code for carrying out instructions for implementing the process. The computer may further comprise a transient memory (e.g. random access memory (RAM)) accessible to the microprocessor while executing the code. The computer may be conveniently mounted in an electrical panel for the system. A plurality of computer-based apparatuses may be connected to one another over a computer network system and geographically distributed. One or more of the computer-based apparatuses in the computer network system may comprise a microprocessor for controlling operations and a non-transient electronic storage medium for storing information about the objects, the conveyor and the one or more grippers, and/or for storing computer executable code for carrying out instructions for implementing the process, and the computer-based apparatuses in the network may interact so that the handling operation may be carried out automatically from remote locations. The output device may be a monitor, a printer, a device that interfaces with a remote output device or the like. The input device may be a keyboard, a mouse, a microphone, a device that interfaces with a remote input device or the like. With a computer, data may be a graphically displayed in the output device.

7 The control software may be configured to manage a variety of functions in the system. The control software may comprise, for example: vision application software configured to process digital data received from the one or more visioning devices into orientation of the objects on the conveyor; orientation control software that calculates rotation angles required; gripper movement software to provide a sequence of movements that the gripper makes for each object; operator interface software to run the user interface;
and software for other functions such as turning the conveyor and other equipment on and off, counting objects going into the holding area, etc. For example, the control software may calculate an initial orientation of the randomly-oriented object, calculate rotation angles necessary to rotate the randomly-oriented object into the predetermined orientation and operate the gripper to rotate the gripped object based on the initial orientation and the calculated rotation angles.
In another aspect, there is provided a process for handling solid three-dimensional biological horticultural objects, the process comprising: singulating a solid three-dimensional biological horticultural object from a plurality of solid three-dimensional biological horticultural object, the singulated object randomly oriented with respect to first and second orthogonal axes; determining the orientation of the randomly-oriented singulated object with a visioning system and comparing the orientation of the randomly-oriented singulated object to a predetermined orientation suitable for further processing;
deploying a gripper to the singulated randomly-oriented object, moving the gripper based on the comparison to suitably orient the gripper with respect to the randomly-oriented object; gripping the randomly-oriented object with the gripper and rotating the gripper about the first and second orthogonal axes to rotate the object from the random orientation into the predetermined orientation; and, deploying the gripper to place the object in the predetermined orientation into a position for further processing.
The singulated randomly-oriented object may comprise a plurality of singulated randomly-oriented objects spaced apart at predetermined locations with respect to the visioning system. The predetermined locations may be separated by the constant spacing.
The gripper may comprise a plurality of grippers operating to substantially simultaneously re-orient the plurality of singulated randomly-oriented objects into the predetermined orientation.
Once the object has been re-oriented into the predetermined orientation, the object may be placed in a position for further processing. The position for further processing may depend on the purpose of the process. In one embodiment, the position for further processing may be a storage area. The storage area may be, for example, a crate, box,

8 carton, tray or the like. The storage area may be temporary, for example an accumulator to temporarily hold the object before being placed in a more permanent storage area. The storage area may be configured for a desired purpose, for example the storage area may be configured as a planter, a container for commercial sale, a shipping container, a long-term storage container or the like.
The solid three-dimensional biological horticultural object may be, for example, a solid three-dimensional plant-based object intended for planting and/or shipping. Some examples of solid three-dimensional biological horticultural objects are plant bulbs (e.g.
flower bulbs) and produce (e.g. fruits and vegetables). Some specific non-limiting examples include tulip bulbs, daffodil bulbs, lily bulbs, hyacinth bulbs, onions, tomatoes, bell peppers, peaches, pears, apples and oranges.
The gripper, system and process advantageously: allow handling objects gently using light pressure to prevent damage; incorporate some degree of mechanical compliancy so that objects of different shapes and sizes may be handled correctly; plants or packages objects in parallel (i.e. multiple objects at the same time) to increase throughput rate; plants or packages objects in a consistent alignment; and/or, are cost effective, for example by avoiding the use of multiple 6-axis industrial robotic manipulators.
Further features will be described or will become apparent in the course of the following detailed description. It should be understood that each feature described herein may be utilized in any combination with any one or more of the other described features, and that each feature does not necessarily rely on the presence of another feature except where evident to one of skill in the art.
Brief Description of the Drawings For clearer understanding, preferred embodiments will now be described in detail by way of example, with reference to the accompanying drawings, in which:
Fig. 1 is an isometric view of a gripper;
Fig. 2 is a dimetric view of the gripper of Fig. 1;
Fig. 3 is an isometric view of the gripper of Fig. 1 without a vertical axis motor;
Fig. 4A is perspective view of the gripper of Fig. 3 in a vicinity of a randomly-oriented object;

9 Fig. 4B depicts the gripper of Fig. 4A having been rotated about a vertical axis to align gripper heads to grip the object at a desired location on the object;
Fig. 4C depicts the gripper of Fig. 4B having gripped the object between the gripper heads;
Fig. 4D depicts the gripper of Fig. 4C having rotated the object to upwardly orient a tip of the object;
Fig. 4E is a front cross-sectional view of a lower portion of the gripper of Fig. 4D;
Fig. 5 depicts a flow chart illustrating a process for planting tulip bulbs in a growing crate;
Fig. 6 depicts a system for handling tulip bulbs in the process of Fig. 5;
Fig. 7 depicts a growing crate in which the tulip bulbs from the system of Fig. 6 are planted;
Fig. 8A is an isometric view of another embodiment of a gripper;
Fig. 8B is a cross-sectional side view of the gripper of Fig. 8A with a piston rod extended;
Fig. 9A depicts the gripper of Fig. 8A with a jamming gripper head lowered to engage an object;
Fig. 9B is a bottom perspective view of Fig. 9A;
Fig. 10 depicts the gripper of Fig. 9A with the jamming gripper head raised with the object held therein;
Fig. 11 depicts the gripper of Fig. 10 having rotated the object about a vertical axis to align gripper heads to grip the object at a desired location on the object;
Fig. 12 depicts the gripper of Fig. 11 having gripped the object between the gripper heads;
Fig. 13 depicts the gripper of Fig. 12 having rotated the object about a horizontal axis to upwardly orient a tip of the object;

Fig. 14 depicts the gripper of Fig. 13 with the object re-gripped by the jamming gripper head; and, Fig. 15 depicts the gripper of Fig. 14 with the object lowered to a storage area.
Detailed Description With reference to Fig. 1, Fig. 2, Fig. 3, Fig. 4A, Fig. 4B, Fig. 4C, Fig. 4D
and Fig.
4E, a mechanical gripper 1 is shown configured for simultaneous orientation of a randomly oriented solid three-dimensional biological horticultural object 20. The gripper 1 comprises a mounting bracket 2 having a horizontally oriented plate 4 on which an upwardly extending vertically oriented drive shaft 3 is fixedly mounted. The drive shaft 3 is rotatable about a vertical rotation axis Z, where rotation of the drive shaft 3 results in rotation of the mounting bracket 2 about the vertical rotation axis Z, i.e. rotation of the mounting bracket 2 in a horizontal plane. The drive shaft 3 is rotatably mounted in a bearing 5 in an assembly mount

10. The drive shaft 3 has a first drive pulley 6 mounted concentrically thereon, the first drive pulley 6 rotatable by a first drive belt 7 driven by a first motor 8 mounted on the assembly mount 10. The first motor 8 is preferably an electric motor, although other motors may be used, for example hydraulic motors, pneumatic motors and the like. The assembly mount 10 is configured to be securely mounted on a support arm (not shown). The support arm may be moveable to permit translation of the entire gripper 1 through space.
The gripper 1 further comprises a first gripper head 30 and a second gripper head 50 opposed to the first gripper head 30. The opposed gripper heads 30, 50 are rotatably and translatably mounted below the mounting bracket 2. The opposed gripper heads 30, 50 are rotatable around and translatable along a horizontal axis X, the horizontal axis X
substantially orthogonal to the vertical rotation axis Z and substantially parallel to the horizontally oriented plate 4. Preferably, the drive shaft 3 is mounted at a center point of the mounting bracket 2 so that the vertical rotation axis Z intersects the horizontal axis X at a point P between and equidistant from the two gripper heads 30, 50. The point P is preferably at or proximate a center of gravity of the object 20 when the gripper 1 grips the object 20.
As best seen in Fig. 4E, the first gripper head 30 comprises a flexible first fingertip 31. The first fingertip 31 is made from a flexible material, for example an elastomer, a thermoplastic or the like, which permits compression and expansion of the first fingertip 31 along the horizontal axis X. The second gripper head 50 likewise comprises a flexible second fingertip 51. The object 20 is gripped between the two fingertips 31, 51 in contact

11 with front faces 32, 52, respectively, of the first and second fingertips 31, 51. The flexible fingertips 31, 51 provide compliancy for properly gripping and orienting objects of different shapes and sizes. Further, damage to the object 20 due to over-gripping by the gripper heads 30, 50 is at least partially mitigated by compression of the flexible first and second fingertips 31, 51. The first and second fingertips 31, 51 may be constructed as bellows, where the first fingertip 31 comprises a first hollow interior 34 open to the atmosphere through a first aperture 33 and the second fingertip 51 comprises a second hollow interior 54 open to the atmosphere through a second aperture 53. Air escapes from the hollow interiors 34, 54 during compression of the first and second fingertips 31, 51 to offer less resistance to compression and greater compliance for gripping the object 20.
The first gripper head 30 further comprises a horizontally oriented first spring-loaded shaft 35 on a distal end of which is mounted the first fingertip 31. The horizontal axis X
passes longitudinally through the first spring-loaded shaft 35. The distal end of the first spring-loaded shaft 35 comprises an outwardly extending first annular protrusion 36 that secures the first fingertip 31 on the first spring-loaded shaft 35. The first spring-loaded shaft 35 is loaded in a first helical spring 37 within a driven hollow first hub 38, the first hub 38 mounted in a bearing 36, the bearing 36 mounted in a vertically oriented first head supporting flange 49. The first hub 38 is rotatable in the bearing 36 about the horizontal axis X, thereby rotating the first spring-loaded shaft 35, which is keyed to the first hub 38 at first mated flat portions 39 of the first hub 38 and the first spring-loaded shaft 35. The first helical spring 37 is contained within a cavity 40 of the first hub 38 through which the first spring-loaded shaft 35 passes. As the gripper heads 30, 50 grip the object 20, the first spring-loaded shaft 35 translates outwardly along the horizontal axis X and the first helical spring 37 is compressed to provide compliancy for properly gripping and orienting objects of different sizes, and to mitigate damage to the object 20 that could have arisen through over-gripping. A first distal stop 41 of the first spring-loaded shaft 35 contains the first helical spring 37 in the cavity 40 at a distal end of the first hub 38, the distal stop 41 abutting against a distal outer surface of the first hub 38 to limit compression of the first helical spring 37. As the object 20 is released by the gripper heads 30, 50, the first helical spring 37 .. expands thereby translating the first spring-loaded shaft 35 inwardly until a proximal stop 42 abuts an outer surface of the bearing 36 to limit further inward translation of the first spring-loaded shaft 35.
To rotate the first spring-loaded shaft 35 about the horizontal axis X, and therefore to rotate the first fingertip 31 about the horizontal axis X, the first hub 38 is drivingly connected to a second motor 48 mounted on the first head supporting flange 49.
The

12 second motor is preferably an electric motor, although other types of motors (e.g. hydraulic motors or pneumatic motors) may be used, A drive belt 45 is looped around the first hub 38 and a drive wheel 47 mounted on a drive shaft of the second motor 48.
Instead of wheels and belts, chains and sprockets may be used to drive the first hub, which may be configured to receive either a belt or chain. Operating the second motor 48 drives drive wheel 47, which drives the belt 45 thereby rotating the first hub 38 about the horizontal axis X.
Although the first spring-loaded shaft 35 is translatable within the first hub 38 along the horizontal axis X, the first spring-loaded shaft 35 and the first hub 38 are keyed together at the mated flat portions 39 thereof to permit the first hub 38 to also rotate the first spring-loaded shaft 35 about the horizontal axis X.
The second gripper head 50 is constructed in a similar manner as the first gripper head 30. Thus, the second gripper head 50 further comprises a horizontally oriented second spring-loaded shaft 55, an outwardly extending second annular protrusion 56, a second helical spring 57, a hollow second hub 58, a bearing 56 mounted in a vertically oriented second head supporting flange 69, second mated flat portions 59, a cavity 60 of the second hub 58, a distal stop 61 and a proximal stop 62. The second gripper head 50 differs from the first gripper head 30 in that the hollow second hub 58 is not driven by a separate motor. Rather the hollow second hub 58 is rotatable in the bearing 56 but only rotates when the object 20 is being gripped between the gripper heads 30, 50 and the first hub 38 is being driven by the second motor 48. Thus, if an object 20 has been gripped, rotation from the motor-driven fingertip 31 will be transmitted to the object 20 and the freely rotating fingertip 51 will follow the rotation and support the gripped object 20.
As best seen in Fig. 1, Fig. 2 and Fig. 3, the gripper 1 further comprises an actuator 70. While a pneumatic actuator is depicted, any other suitable actuator may be used, for example a hydraulic actuator or an electric actuator. The actuator 70 is mounted on an underside of the horizontally oriented plate 4. The first and second head supporting flanges 49, 69 are mounted on or proximate opposite ends of the actuator 70 so that the first and second fingertips 31, 51 oppose each other and are symmetrically disposed on either side of the point P on the horizontal axis X of the rotatable gripper heads 30, 50.
The actuator 70 comprises a first arm 71 on which the first head supporting flange 49 is mounted, and a second arm 72 on which the second head supporting flange 69 is mounted. The actuator 70 comprises rods 75, whereby operation of the actuator 70 causes rods 75 to retract or extend, which causes the first and second head supporting flanges 49, 69 to translate relative to each other in a direction parallel to the horizontal axis X of the opposed gripper heads 30, 50. Retraction of the rods 75 causes the supporting flanges 49, 69 to translate

13 toward each other, thereby causing the opposed gripper heads 30, 50 to translate toward each other. Extension of the rods 75 causes the supporting flanges 49, 69 to translate away from each other, thereby causing the opposed gripper heads 30, 50 to translate away from each other. Operation of the actuator 70 therefore permits gripping and releasing of the object 20.
With reference to Fig. 4A, Fig. 4B, Fig. 4C, Fig. 4D and Fig. 4E, a process of re-orienting an object using the gripper 1 is illustrated. As shown in Fig. 4A, to properly grip the randomly oriented object 20, the gripper 1 is moved to a vicinity of the object 20 (or the object 20 is moved to a vicinity of the gripper 1) and the gripper 1 is centered over the object 20. As shown in Fig. 4B, the entire gripper 1 is rotated about the vertical rotation axis Z until the horizontal axis X of the opposed gripper heads 30, 50 is parallel to a transverse axis T
through a center of gravity C of the object 20, the transverse axis T
typically passing through a widest section of the object 20. The transverse axis T is substantially orthogonal to a main axis M of the object 20 passing through a tip 21 of the object 20, The gripper 1 is rotated about the vertical rotation axis Z by operating the first motor 8 (see Fig. 1) to rotate the vertically oriented drive shaft 3.
As shown in Fig. 4C, the gripper 1 is then moved (e.g. lowered) so that the object is between the opposed gripper heads 30, 50 with the center of gravity C of the object 20 substantially co-located in space with the point P on the horizontal axis X
of the opposed 20 gripper heads 30, 50. The gripper head supporting flanges 49, 69 are translated inwardly by action of the actuator 70 to grip the object 20 between the first and second fingertips 31, 51 of the first and second gripper heads 30, 50, respectively. Absolutely precise movement of the actuator 70 is not required because the compliance in the first and second gripper heads 30, 50 due to compression of the first and second fingertips 31, 51 and compression of the first and second helical springs 37, 57 permits gripping the object 20 without damage even when the actuator 70 translates the gripper head supporting flanges 49, 69 further inward toward point P than would be absolutely required, as seen in Fig. 4C.
As shown in Fig. 4D, with the object 20 gripped between the first and second fingertips 31, 51, the object 20 may be rotated about the horizontal axis X so that the tip 21 and therefore the main axis M of the object 20 are vertically oriented.
Rotation of the object 20 gripped between the first and second gripper heads 30, 50 is effected by operation of the second motor 48 as described previously. When the object 20 is a tulip bulb, Fig. 4D
shows the desired orientation for planting the tulip bulb where the tip 21 is pointing upwardly (i.e. roots are down). If the tulip bulb is to be packaged instead of planted, the tulip bulb

14 may be rotated about the horizontal axis X so that the tip 21 points downwardly instead of upwardly.
Fig. 5 depicts a flow chart illustrating a process 100 for planting tulip bulbs in growing crates. The process 100 is illustrated as three connected sub-processes, which are: growing crate handling 110; bulb handling 120; and, computer visioning 150.
The crate handling 110 sub-process comprises providing growing crates pre-filled with soil 111 and transferring the pre-filled growing crates to an indexed conveyor 112.
Each crate is advanced in an indexed manner to a next row of bulbs 113 being handled by the bulb handling sub-process 120, where the crate waits for a row of bulbs to be planted therein 114 by the bulb handling sub-process 120. When a row of bulbs is planted in the crate, a determination is made as to whether the crate is now full 115. If the determination is 'No' and the crate is not yet full, the crate remains in position to wait further 113 for a next row of bulbs to be planted therein 114. If the determination is 'Yes' and the crate is full, the full crate is advanced to an unloading station 116 where the crate is unloaded from the conveyor as a growing crate filled with tulip bulbs 117. A plurality of growing crates is processed in this manner until there are no more tulip bulbs to be planted.
The unloaded crates are then transported to a storage facility.
The bulb handling sub-process 120 comprises providing bulk tulip bulbs 121 and dumping the tulip bulbs into a hopper 122. The bulbs from the hopper are singulated 123 and released intermittently on to a conveyor at a constant spacing and in a random orientation 124. The bulbs singulated on the conveyor pass within a Field of View of a visioning system 125, where the computer visioning sub-process 150 obtains information (e.g. digital images or point cloud data) about each bulb 151 (e.g. with a 3D
camera or a line scan), calculates orientation of each bulb 152 (e.g. with a programmed computer) and calculates required rotation angles for each bulb 153 (e.g. with the programmed computer).
The conveyor is stopped when a predetermined number (N) of the bulbs are in picking positions 126. A number N of grippers simultaneously pick and orient the N
bulbs 127 based on the rotation angles calculated by the computer visioning sub-process 150 for each bulb.
Prior to gripping the bulb, and based on the calculated rotation angles for a given bulb, the corresponding gripper is first rotated about the mounting bracket rotation axis by an amount sufficient to orient the gripper head rotation axis substantially orthogonally with the main axis of the bulb, the main axis being an axis passing through the tip and a centroid (i.e. the center of gravity) of the bulb. After the bulb is gripped, the bulb is rotated about the gripper head rotation axis to vertically orient the main axis of the bulb.
Once the main axis is re-oriented to the vertical and before releasing the bulb, the gripper is again rotated about the mounting bracket rotation axis to bring the bulb into a final orientation for transfer into an accumulator. Thus, although the randomly oriented bulbs have three possible rotational degrees of freedom, and therefore need up to three rotation angles to fully re-define their orientations, the gripper only has and only requires two degrees of freedom to complete the three rotations to properly re-orient the bulbs based on the calculated rotation angles.
In this manner, any randomly oriented bulb can be rotated into any specified orientation.
The N bulbs are transferred into the accumulator 128 by the grippers, and a determination is made as to whether the accumulator is now full 129. If the determination is 'No' and the accumulator is not yet full, the accumulator remains in position for a next predetermined number (N) of the bulbs to be transferred into the accumulator 128. If the determination is Yes' and the accumulator is full, spacing between the bulbs in the accumulator is reduced 130, and the bulbs in the accumulator are transferred into the growing crate 131, which is waiting for a row of bulbs to be planted therein 114 in the growing crate handling sub-process 110. Transferring the bulbs from the accumulator to the growing crate can be accomplished by a robot.
With reference to Fig. 6 and Fig. 7, a system 200 is depicted for handling tulip bulbs 220 (only one labeled). The system 220 comprises a conveyor belt 205 on to which the tulip bulbs 220 are singulated at a constant spacing d and in a random orientation by passing a plurality of the tulip bulbs 220 on a feed chute 201 through a singulating gate 202. The bulbs 220 pass through a field of vision of a digital camera 210, which acquires digital images of the bulbs 220 on the conveyor belt 205 as the bulbs 220 pass through the field of vision. Image data is transmitted to a computer (not shown) programmed to calculate the orientation of each randomly oriented bulb 220 and then calculate required rotation angles to bring each of the bulbs 220 into a predetermined orientation for placement into an accumulator 225 (e.g. an egg crate foam holder) proximate the conveyor belt 205.
When enough of the bulbs 220 reach a picking station comprising a plurality of grippers 1 (three shown and labeled) as described in connection with Fig. 1, the conveyor belt 205 stops. In the illustrated embodiment, the grippers 1 are spaced apart longitudinally over the conveyor belt 205 by a distance equal to the constant spacing d between the tulip bulbs 220. Thus, when the conveyor 205 stops, each of the grippers 1 has a randomly oriented tulip bulb 220 directly below the point P (see Fig. 1) of each of the grippers I. Each of the grippers 1 is independently rotated about respective vertical axes by rotating the drive shafts 3 of each of the grippers 1 through angles calculated by the computer for the individual tulip bulbs 220. The grippers 1 are under the control of the computer and are rotated automatically rotated by the computer based on the angles calculated by the computer. Each of the grippers 1 is shown in Fig. 6 having been first rotated about their respective vertical axes by an angle suitable for gripping the respective randomly oriented tulip bulbs 220 along the bulb's transverse axis through the center gravity of the bulb, as described above.
After the grippers 1 grip the tulip bulbs 220, the grippers 1 then rotate the gripped bulbs 220 about the respective horizontal gripper head rotation axes to orient the bulbs with tips pointing upward. A final rotation of the grippers 1, about the respective vertical axes brings the bulbs into a final orientation before depositing the bulbs in the accumulator 225.
The grippers 1 may be mounted on one or more, preferably one, translatable arm (not shown), which is configured to translate the grippers 1 transversely with respect to the conveyor belt 205 to position the grippers 1 over the accumulator 225. Once over the accumulator 225, the grippers 1 may release the bulbs 220 into individual cells of the accumulator 225. Either the accumulator 225 or the grippers 1 may be translatable longitudinally with respect to the conveyor belt 205 so that the grippers 1 are able to fill the cells of the accumulator 225. Preferably, the translatable arm is configured to translate the grippers 1 both transversely and longitudinally. Once the grippers 1 have deposited the bulbs 220 in the accumulator 225, the conveyor belt 205 is switched on under the control of the computer to bring the next batch of bulbs 220 into position to be gripper by the grippers I.
The bulbs 220 in the accumulator are transferred to a crate 230 (see Fig. 7), for example by another robot or workers. If the crate 230 is a growing crate as illustrated in Fig. 7, the bulbs 220 are placed in the crate 230 with roots down (tips up).
If the bulbs 220 are being packaged for a storage, a crate with a plurality of pins protruding from a floor of the crate may be lowered over the accumulator so that the pins pierce the tip of the bulbs and the bulbs are stored in the crate with roots up (tips down).
With reference to Fig. 8A, Fig. 8B, Fig. 9A, Fig. 9B, Fig. 10, Fig. 11, Fig.
12, Fig. 13, Fig. 14 and Fig. 15, another embodiment of a mechanical gripper 300 is shown configured for simultaneous orientation of a randomly oriented solid three-dimensional biological horticultural object 320.
The gripper 300 comprises an upwardly extending vertically oriented housing on which a mounting bracket 302 having a horizontally oriented plate 304 is fixedly mounted. The housing 380 comprises a top mounting flange 389 through which the gripper 300 may be connected to external hardware. The housing 380 contains a linear actuator 381 having a piston rod 303 that is rotatable about a vertical rotation axis N
and translatable along the vertical rotation axis N. An end of the piston rod 303 is equipped with a jamming gripper head 385, although another device such as a suction cup or pincer can be used, which is connected to the piston rod 303 by a collar 387. Rotation of the linear actuator 381 rotates the piston rod 303 resulting in rotation of the jamming gripper head 385 about the vertical rotation axis N. The piston rod 303 in this embodiment acts as a drive shaft for the jamming gripper head 385. The linear actuator 381 is rotatably mounted on bearings 305 situated in the housing 380. The linear actuator 381 is operatively coupled to a motor 308, operation of the motor 308, causing the linear actuator 381, and therefore the jamming gripper head 385, to rotate about the vertical rotation axis N. The motor 308 is preferably an electric motor, although other motors may be used, for example hydraulic motors, pneumatic motors and the like. Instead of a linear actuator, other types of actuators may be employed, for example hydraulic or pneumatic cylinders, provided the actuator is capable of translating the jamming gripper head 385 along the vertical rotation axis N.
The jamming gripper head 385 comprises a flexible membranous sac filled with a flowable granular material (e.g. sand, coffee grounds, plastic beads or the like). The sac is connected to a source of inflation fluid (e.g. air) and a source of vacuum through ports 386 on the jamming gripper head 385. When inflated, the jamming gripper head 385 is deformable and may be pushed on to the object 320, the membranous sac conforming to a surface of the object 320. When a vacuum is applied, the jamming gripper head 385 deflates, the fluid between granules of the granular material is removed and the granules 'jam' thereby locking in place. The jamming gripper head 385 holds the deflated shape thereby gripping the object 320.
The gripper 300 further comprises a first rotatable gripper head 330 and a second rotatable gripper head 350 opposed to the first gripper head 330. The opposed gripper heads 330, 350 are rotatably and translatably mounted below the mounting bracket 302.
The opposed gripper heads 330, 350 are rotatable around and translatable along a horizontal axis M, the horizontal axis M substantially orthogonal to the vertical rotation axis N and substantially parallel to the horizontally oriented plate 304. The piston rod 303 of the linear actuator 381 extends through an aperture in the plate 304 so that the jamming gripper head 385 is below the plate 304. Preferably, the piston rod 303 is situated to extend through at a center point of the mounting bracket 302 so that the vertical rotation axis N intersects the horizontal axis M at a point Q between and equidistant from the two opposed gripper heads 330, 350. The point Q is preferably at or proximate a center of gravity of the object 320 when the gripper 300 grips the object 320. The opposed gripper heads 330, 350 may be the same as those previously described in connection with the gripper 1.
The opposed gripper heads 330, 350 are mounted on opposed supporting flanges 349, 369, respectively, which are slidingly mounted on and depend vertically downward from the mounting bracket 302. The opposed gripper heads 330, 350 are rotated about the horizontal axis M by a motor 348 mounted on the supporting flange 349 and operatively coupled through bevel gears 345 to the gripper head 330. The gripper head 350 is an idler and is rotated along with gripper head 330 when the object 320 is gripper between the opposed gripper heads 330, 350.
The gripper 300 further comprises an actuator 370, for example a motor, mounted on a topside of the horizontally oriented plate 304 and operatively coupled to the supporting flanges 349, 369. The supporting flanges 349, 369 comprise sliders 376, 377, respectively, slidingly mounted on a slide rail 375, the slide rail 375 mounted on an underside of the mounting bracket 302, as best seen in Fig. 9B and Fig. 10 Operation of the actuator 370 causes sliders 376, 377 and therefore the supporting flanges 349, 369 to translate horizontally on the slide rail 375 along the underside of the mounting bracket 302, thereby causing the opposed gripper heads 330, 350 to translate toward or away from each other along the horizontal axis M. Operation of the actuator 370 therefore permits gripping and releasing of the object 320 from the opposed gripper heads 330, 350.
With reference to Fig. 8A, Fig. 9A, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig.
14 and Fig. 15, a process of re-orienting the object 320 using the gripper 300 is illustrated.
As shown in Fig.
8A, the gripper 300 is first positioned over the randomly oriented object 320 so that the object 320 is substantially directly below the jamming gripper head 385. As shown in Fig.
9A, the piston rod 303 is extended to lower the jamming gripper head 385 to engage the object 320, the jamming gripper head 385 operated to then grip the object 320.
As shown in Fig. 10, the piston rod 303 is then retracted to raise the jamming gripper head 385 with the object 320 gripped therein to a point where the center of gravity of the object 320 is at the point Q. As shown in Fig. 11, the motor 308 is used to rotate the linear actuator 381 about the vertical rotation axis N thereby rotating the jamming gripper head 385 and the object 320 gripped therein so that a transverse axis through the center of gravity of the object 320 is oriented substantially parallel to the horizontal axis M of the opposed gripper heads 330, 350. As shown in Fig. 12, the gripper head supporting flanges 349, 369 are then translated inwardly by action of the actuator 370 to grip the object 320 between the opposed gripper heads 330, 350. As shown in Fig. 13, the jamming gripper head 385 is then operated to release the object 320, and the piston rod 303 is further retracted to raise the jamming gripper head 385 out of the way of the object 320. With the jamming gripper head 385 moved out of the way, the opposed gripper heads 330, 350 may be rotated by operation of the motor 348 to rotate the object 320 about the horizontal axis M to vertically orient a tip 321 of the object 320. As shown in Fig. 14, with the tip 321 of the object 320 vertically oriented, the piston rod 303 is extended to lower the jamming gripper head 385 to engage the object 320, where the jamming gripper head 385 is again operated to grip the object 320. As shown in Fig. 15, the piston rod 303 is further extended to lower the jamming gripper head 385 with the object 320 gripped therein to place the object in a storage area where the jamming gripper head 385 is operated to release the object 320. In this manner, the object 320 may be placed in a storage area without the need to first place the object 320 in an intermediate area and without the need for a further gripper to transfer the object 320 to the storage area.
The novel features will become apparent to those of skill in the art upon examination of the description. It should be understood, however, that the scope of the claims should not be limited by the embodiments but should be given the broadest interpretation consistent with the wording of the claims and the specification as a whole.

Claims (19)

Claims:

1. A gripper for gripping and re-orienting a solid three-dimensional biological horticultural object, the gripper comprising:
a mounting bracket;
opposed first and second rotatable gripper heads rotatably mounted on the mounting bracket, the opposed first and second rotatable gripper heads rotatable about a common gripper head rotation axis;
a translation actuator configured to translate at least one of the opposed rotatable gripper heads along the gripper head rotation axis to grip a solid three-dimensional biological horticultural object between the opposed first and second rotatable gripper heads;
a drive shaft configured to rotate the object about a second rotation axis substantially orthogonal to the gripper head rotation axis, the second rotation axis passing between the opposed first and second rotatable gripper heads; and, at least one rotation actuator, the at least one rotation actuator configured to rotate the drive shaft to thereby rotate the object, and the at least one rotation actuator configured to rotate at least one of the opposed rotatable gripper heads to thereby rotate the object gripped between the opposed first and second rotatable gripper heads.

2. The gripper of claim 1, wherein the drive shaft is connected to the mounting bracket and the drive shaft is configured to rotate the mounting bracket about the second rotation axis.

3. The gripper of claim 2, wherein the drive shaft is mounted on a first side of the mounting bracket, the translation actuator is mounted on a second side of the mounting bracket opposed to the first side along the second rotation axis, and the opposed first and second rotatable gripper heads are rotatably mounted on first and second opposed flanges, respectively, the first and second opposed flanges mounted on opposed translatable elements of the translation actuator, whereby movement of the opposed translatable elements causes the opposed flanges to move toward or away from each other thereby translating the opposed rotatable gripper heads along the gripper head rotation axis.

4. The gripper of claim 1, wherein the drive shaft is connected to a third gripper head and the drive shaft is configured to rotate the third gripper head about the second rotation axis.

5. The gripper of claim 4, wherein the third gripper head is translatable along the second rotation axis.

6. The gripper of claims 4 or 5, wherein the third gripper head comprises a jamming gripper head.

7. The gripper of any one of claims 1 to 6, wherein the second rotation axis and the gripper head rotation axis are the only rotation axes on the gripper.

8. The gripper of any one of claims 1 to 7, wherein the at least one rotation actuator comprises a first rotation actuator configured to rotate the at least one of the rotatable gripper heads, and a second rotation actuator configured to rotate the drive shaft.

9. The gripper of any one of claims 1 to 8, wherein the second rotation axis intersects the gripper head rotation axis.

10. The gripper of any one of claims 1 to 9, wherein the first gripper head, the second gripper head or both the first and second gripper heads are compliant.

11. The gripper of claim 10, wherein at least one of the gripper heads comprises a flexible fingertip compressible along the gripper head rotation axis.

12. The gripper of claim 10 or 11, wherein at least one of the gripper heads comprises a spring that biases the at least one of the gripper heads along the gripper head rotation axis.

13. A gripping system for gripping and re-orienting a solid three-dimensional biological horticultural object, the gripping system comprising:
at least one gripper as defined in any one of claims 1 to 12;
a visioning device configured to capture information about a randomly-oriented solid three-dimensional biological horticultural object to be gripped and re-oriented; and, a controller operably linked to the gripper and the visioning device, the controller programmed to position and orient the gripper in a first configuration suitable for gripping the randomly-oriented object based on the information about the object captured by the visioning system, operate the gripper to grip the randomly-oriented object between the first and second gripper heads of the gripper, and operate the gripper to rotate the gripped object from the random orientation into a predetermined orientation, the predetermined orientation based on predetermined parameters for suitably orienting the object for further processing.

14. The system according to claim 13, wherein the controller calculates an initial orientation of the randomly-oriented object, calculates rotation angles necessary to rotate the randomly-oriented object into the predetermined orientation and operates the gripper to rotate the gripped object based on the initial orientation and the calculated rotation angles.

15. The system of claim 13 or 14, further comprising a conveyor on which a plurality of the randomly-oriented objects are singulated at a constant spacing to pass through a field of view of the visioning device.

16. The system of claim 15, wherein the gripper comprises a plurality of grippers longitudinally separated along the conveyor by the constant spacing, each of the plurality of grippers operated by the controller to grip a corresponding singulated object on the conveyor.

17 The system of any one of claims 13 to 16, wherein the object is a tulip bulb.

18. A process for handling solid three-dimensional biological horticultural objects, the process comprising:
singulating a solid three-dimensional biological horticultural object from a plurality of solid three-dimensional biological horticultural object, the singulated object randomly oriented with respect to first and second orthogonal axes;

determining the orientation of the randomly-oriented singulated object with a visioning system and comparing the orientation of the randomly-oriented singulated object to a predetermined orientation suitable for further processing;
deploying a gripper to the singulated randomly-oriented object, moving the gripper based on the comparison to suitably orient the gripper with respect to the randomly-oriented object;
gripping the randomly-oriented object with the gripper and rotating the gripper about the first and second orthogonal axes to rotate the object from the random orientation into the predetermined orientation; and, deploying the gripper to place the object in the predetermined orientation into a position for further processing.

19. The process of claim 18, wherein: the singulated randomly-oriented object comprises a plurality of singulated randomly-oriented objects spaced apart at predetermined locations with respect to the visioning system; the gripper comprises a plurality of grippers, the plurality of grippers operating to substantially simultaneously re-orient the plurality of singulated randomly-oriented objects into the predetermined orientation; and, the plurality of objects in the predetermined orientation are placed into a position for further processing.