System and method for adaptive bin picking for manufacturing

A system and method for automatically moving one or more items between a structure at a source location and a destination using a robot is provided. The system includes first and second vision systems to identify an item and to determine the precise location and orientation of the item at the source location and the precise location and orientation of the destination, which may or may not be in a fixed location. A controller plans the best path for the robot to follow in moving the item between the source location and the destination. An end effector on the robot picks the item from the source location, holds it as the robot moves, and places the item at the destination. The system may also check the item for quality by one or both of the vision systems. An example of loading and unloading baskets from a machine is provided.

BACKGROUND

Assembly processes (or lines) are implemented to produce a finished good. The finished goods are a combination of various parts that are attached together through various techniques. A finished good may be any sort of object or product, for example, those sold in commerce. An automobile or vehicle, or a part of an automobile or vehicle, may be a finished good produced via an assembly process. Many aspects of a manufacturing process involve moving items, such as individual parts, assemblies, or carriers holding one or more individual parts or assemblies for transport or for processing together.

Many finished goods include parts from a variety of sources, which are transported to and within manufacturing locations to be combined into finished goods or into assemblies or sub-assemblies thereof. These parts are frequently transported in bins, where they may be loose, having random locations and orientations. Parts must be transferred from the bins to a destination to facilitate the use of the part in the manufacturing process. Parts are also frequently processed in batches using specialized carriers such as baskets, bins, or paint bucks, which must be loaded and unloaded with individual parts or assemblies. Also, in some cases, movement of the carriers requires special handling due to the requirements of the manufacturing process and/or other considerations such as weight and/or size of the loaded or unloaded carriers.

For many portions of a manufacturing process, the current technique of moving items is a manual process. Special considerations are required in moving large and/or heavy items. For example, stamped metal parts are commonly picked by a human from a bin and placed into a fixture for further processing (e.g., cutting, welding, adhesion, or painting). After processing, the human may pick the parts from a fixture and place them into a bin, which may be a new bin or the same bin from which the parts originated. During the pick/place operations, the human may also perform quality checks on the part.

In another example a process of loading vehicle fascias onto paint bucks, or racks used in paint processes, may require a crew, with persons alternating between picking from the walk-in bin (at floor level) and placing the parts in a buck (at hip level) by transferring the part to each other in order to relieve the ergonomic stressors.

In yet another example, a process of loading and unloading baskets of parts to be washed from a washing machine may be performed manually, and/or with the aid of a crane, which may be required by health and safety regulations for baskets that weigh more than a predetermined amount.

In this way, each item that enters a given step of the manufacturing process may require a manual operation of picking and placing the part at a destination location and orientation that is suitable for the next step in the manufacturing process. Heavy items may cause fatigue in the humans who perform these operations. The use of a mechanical aid, such as a crane, may be required to move heavy items; however, such mechanical aids may be difficult to use and may not be embraced by staff. Repetitive motions, may contribute to costly injuries, particularly with moving heavy items. These manual operations may introduce delays and inefficiencies to the overall assembly line process.

SUMMARY

A conveyance system and method for automatically moving one or more items between a source location and a destination using a robot is provided. The system includes a first vision system to identify an item and to determine a pick location and a pick orientation of the item upon a structure. A second vision system determines the location and orientation of a destination. A controller plans the best path for the robot to follow in moving the item between the pick location and the destination. An end effector is attached to the robot for picking the item and holding the item as the robot moves the item to the destination. The end effector then releases, or places the item at the destination location and with a destination orientation.

The method includes the steps of identifying an item having a non-fixed location and orientation at the source location using a first vision system; determining the pick location and pick orientation of the item within the source location using the first vision system; and determining the location and orientation of a destination using a second vision system. The method also includes the step of performing adaptive trajectory planning to determine the best path between the pick location and the destination.

The method proceeds with the steps of picking the item from the pick location by the end effector on the robot; moving the item along the best path by the robot; placing the item at the destination by the end effector on the robot. The method may also include the step of checking the part for quality by one or both of the vision systems.

Employing the aspects disclosed herein, a system and method may automatically move one or more items between a bin at the source location and a destination using a robot with an end effector. The flexible fixtures disclosed herein allow for a variety of part types to be moved from a bin where they may be loose, having random locations and orientations. Further, due to the automated nature of the methods discussed herein, gains in efficiency and resource reduction are achieved.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The invention is described more fully hereinafter with references to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough, and will fully convey the scope of the invention to those skilled in the art. It will be understood that for the purposes of this disclosure, “at least one of each” will be interpreted to mean any combination the enumerated elements following the respective language, including combination of multiples of the enumerated elements. For example, “at least one of X, Y, and Z” will be construed to mean X only, Y only, Z only, or any combination of two or more items X, Y, and Z (e.g., XYZ, XZ, YZ, X). Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals are understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience.

Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a conveyance system20and method for automatically moving one or more items21between a structure at a source location26and a destination28using a robot30with an end effector32are disclosed.

One example of the conveyance system20of the present disclosure is shown inFIG. 1for automatically moving one or more parts22between a bin24at a source location26and a destination28using a robot30with an end effector32, and where the parts22may be loose or not fixed in specific locations in the bin24. As used in this disclosure, a bin24may include any box, rack, tray, or other carrier for holding parts22. It should be appreciated that the term “part”22as discussed throughout the subject disclosure, including the claims, may encompass various types of objects including, but not limited to, raw materials, housings, and component pieces in any stage of manufacture, assemblies or sub-assemblies in any stage of construction, and finished pieces or assemblies. A variety of different items21may be accommodated and moved by the same conveyance system20, using the same or different end effectors32. It should also be appreciated that the term “item”21may refer to a part22, a bin24, or any other physical item including, but not limited to a tool, part, fixture, raw material, housing, component piece in any stage of manufacture, assembly or sub-assembly in any stage of construction, finished pieces or assemblies, a box, rack, tray, or other carrier.

As best shown inFIG. 1, a first vision system34may identify a part22within the bin24at a source location26and determine a pick location, and a pick orientation of the part22. A second vision system38may determine the location and orientation of a destination28, which may be inside or outside of the bin24. The destination28may be any place where one or more parts are to be moved, including, for example: fixtures or carriers for manufacturing or inspection, shipment, etc.; racks or packages for storage or conveyance; conveyors; fixtures or assemblies in any stage of manufacture. The destination28may be fixed in position and orientation. The destination28may be variable in position and/or orientation, such as for parts being placed on an assembly as it moves along an assembly line. Additionally, the destination28for each of a series of parts22may be different, for example in cases where a rack, or other such assembly is loaded with a plurality of parts22, with each part22in a separate compartment or location on the rack.

Each of the vision systems34,38may be any type of machine vision system, including one or more cameras36or other imaging devices and including but not limited to 2D, 2.5D, and 3D systems capable of identifying and locating a part22in 3-dimensional space, having x, y, and z coordinates, as well as a 3-dimensional orientation of roll, pitch, and yaw. One example of such a machine vision system is the camera system manufactured by Cognex. Such identifying and locating may be done using direct observations and measurements, through comparisons with one or more reference images, through any other method or combination of methods.

The conveyance system20includes a robot30having an end effector32to pick the part22from the bin24, move the part22along a path40, and place the part22at the destination28. The end effector32may be an advanced effector (e.g., tooling), or any other effector capable of moving an item21including, but not limited to, a grasp, clamp, and a suction device. The system also includes a controller42for planning a best path40for the robot30to follow in moving the item21between the source location26and the destination28.

Each of the vision systems34,38may include one or more cameras36located at fixed positions, as shown onFIG. 1. Alternatively or additionally, the first vision system34may include a camera36that is located on the robot30, as shown onFIG. 2. More specifically, the camera36may be located on or near a free or distal end of the robot30. The camera36may be located on the end effector32of the robot30or on another part of the robot30, such as a joint or a structural component near the end effector32. Such a robot-mounted camera36may be used instead of or in addition to one or more cameras36at fixed positions. Alternatively or additionally, the second vision system38may include a camera36that is located on the robot30. In one embodiment, the vision systems34,38may share one or more cameras36that are mounted on the robot30. In other words, the vision systems34,38may each be configured to use a shared camera mounted on the robot. Such a configuration may include one of the vision systems34,38passing an image signal from the shared camera to the other one the vision systems34,38. Alternatively, an image from the shared camera may be provided to each of the vision systems34,38from the shared camera or from another device, such as a signal splitter.

As shown inFIG. 3, an example application of the conveyance system20of the present invention may be to replace a manual operation of loading and unloading vehicle fascias onto paint bucks, or racks used in paint processes. For example, the process of loading the paint bucks may require a crew, with persons alternating between picking from the walk-in bin (at floor level) and placing the parts in a buck (at hip level) and by transferring the part to each other in order to relieve the ergonomic stressors. As shown inFIG. 3, the conveyance system20of the present invention may replace the manual loading and unloading of vehicle fascias to and from paint bucks and may allow the combined operation to be performed with fewer persons per shift. The bins24may be located within a general window area, which may be a predetermined tolerance value from a predetermined nominal position or boundary. The bins24may not need to be secured or placed in an exact location, and therefore may not require locating fixtures. The parts22may be fixed within the bins24, such as by fixtures formed in the bins24, and the number of parts within a bin24may vary. The conveyance system20of the present disclosure may accommodate several different types of parts, such as for different vehicle models. For example, a conveyance system20may accommodate 17 or more different types of parts. According to an aspect, the conveyance system20may require both the source and the destination to be stationary. Alternatively, the conveyance system20may allow the loading and unloading of bucks which are moving in up to two different directions simultaneously, such as may result from being moved along a curved segment of conveyor track. The conveyance system20of the present disclosure may provide for faster and/or more consistent cycle times in loading or unloading parts22when compared to the manual loading and unloading operations of the prior art and may allow for a direct labor reduction from 5 persons per shift to 1 person per shift.

As shown inFIG. 3, the conveyance system20may be used to control a robot30to move one or more parts22into and out of a machine44. The robot30may pick one or more parts22from a source location26, which may be, for example, a first bin24holding raw, or unfinished parts22, and carry the parts22to the machine44for processing, after which the robot30may remove pick the finished parts22to a destination28, which may be, for example, a second bin24for transporting the finished parts22to another area. In the example shown inFIG. 3, the robot30may load and unload right-hand (RH) and left-hand (LH) parts22for simultaneous processing by the machine44. The conveyance system20may accommodate some variation in the placement of the bins24used for the source location26and the destination28. Such variation may allow the source and destination bins26,28to be located anywhere within a window of space in each direction from a nominal position. Therefore, the bins24do not need to be secured in a precise location and may not require a locating fixture. The robot30may accommodate for variations in the location and tolerances of the parts22. According to an aspect, the conveyance system20may inspect the finished parts22, to ensure that the finished parts22were properly processed by the machine44before the parts22are allowed to be processed further. Such an inspection may be, for example, a hole inspection to verify that holes are properly made in the parts22. According to a further aspect, conveyance system20may accommodate a variation in the number of parts22or bins24located at the source location26and/or the destination28, such as variations in the stack height, and may automatically pick or place parts22from the top of a stack of bins24. Such a system20may replace a current manual loading and unloading operation and may occupy the same or a smaller square footage footprint on a building floor. The example shown inFIG. 3may allow a reduction from 1 to 0 direct labor on each shift to perform the loading and unloading of parts22from the machine44.

As shown inFIG. 4, an example application of the conveyance system20of the present invention may be to replace a manual operation of loading and unloading baskets46of parts22into and out of a machine44. In the example shown, the machine44is a washer with an input belt48for receiving baskets46of dirty parts22and an output belt50for removal of baskets46cleaned parts22. Parts22to be washed arrive in a basket46and are placed in a defined position on a rack inside the basket46. The operator may load a basket46from a source location26onto the input belt48and may then unload the basket46from the output belt50by moving the basket46to a destination28. The baskets46, with parts22may require the use of a mechanical aid such as a crane52to lift in order to be compliant with health and safety regulations. The use of a crane52may be difficult and/or cumbersome to use and may not be embraced by staff. The operator loading and unloading the machine44may perform quality, quantity, and data logging tasks on the parts22.

The process of manually loading and unloading a washing machine44may involve the following steps:

Step 1: The operator takes the basket46off a standing/fixed delivery carriage54and places the basket46on the input belt48on the right side of the washing machine44.

Step 2: The operator takes the basket46off the output belt50on the left side of the washing machine44and places the basket46on a stationary carriage56in a defined area with. Stack height may vary depending on how many baskets46are already in place on the carriage56.

As illustrated inFIG. 4, the carriage56may be fixed, being stationary and located in a general predetermined location window, shown as a taped rectangle on the floor, but the carriages56do not need to be located or secured in a precise position such as by using a mechanical carriage fixing device. The loading and unloading operations are not time-critical. The cycle time of the machine may allow for some variation in when the baskets46are loaded and unloaded. The loading and loading operations may require careful handling. The baskets46may vary in weight and height to accommodate different numbers and types of parts22. Due to the physical constraints of the machine44and the carriages54,56, fencing for a traditional robot cell around the machine44may not be feasible.

As shown inFIG. 4, the conveyance system20including a robot30may be used to load and unload baskets46of parts22from the washing machine44. The system20may locate a basket46from the standing/fixed delivery carriage54and may pick the basket46with an end effector32on the robot30, which may place the basket46on the input belt48(dirty parts) of the washing machine44. The system20may detect and locate a basket46on the output belt50of the washing machine44and may move the basket46onto stack on a carriage56. The conveyance system20may use cameras36accommodate baskets46that vary in size and weight and which are not fixed in a specific location. The conveyance system20may perform quantity, quality inspection, and data logging tasks. The conveyance system20may allow baskets to be stacked at different positions on a carriage56which may vary according to the existing load on that carriage56. The system20may provide for loading and unloading cycle times of less than 80 s to prevent any bottleneck at the loading or unloading steps. The robot30may have TUV certified skin technology and may recognize and/or inform humans in the working area. In this way, the robot30may be able to operate without protective fencing.

FIGS. 4 and 5provide schematic views of the conveyance system20of the present disclosure as used for the example application of loading and unloading baskets46of parts22from a washing machine44.

As shown inFIG. 4, a first vision system34including at least one camera36may identify a basket46including its precise pick location and pick orientation in the source location26, which may be delivery carriage54holding a stack of one or more baskets46. The robot30may pick the basket46from the source location26and move the basket46to the input belt48of the washing machine44. A camera36may not be required to cover the input and/or output belts48,50, as those locations may be fixed, and their status as empty or loaded with a basket46may be communicated to the conveyance system20from the machine44. The conveyance system20may also perform the step of unloading the washing machine44by picking up a basket46from the output belt50and placing that basket at a destination location28, which may be the top of a stack of other baskets46upon a carriage56. The precise location and orientation of the destination28may vary according to the exact location of the carriage and/or the height of the stack of baskets46and may be determined by the second vision system38using one or more cameras36. The system20may provide adaptive trajectory planning to determine the best path to move the baskets46.

As illustrated inFIG. 5, the system20may include a controller42for planning a best path40for the robot30to follow in moving an item21, which may be a basket46, between the source location26and the destination28. One or more cameras36may provide a 3-dimensional view to detect the exact position of a basket46. The system20may also detect the number and shape of individual parts22in the basket46. The controller42may perform several functions in the system20, which may include, for example, 2D inspection of a basket46and parts22therein; 3D perception and localization; perception and load & force measurement; production process sequencing, providing a production graphical user interface (GUI); calibration and configuration software; and Production process specific motion planning and control, including the control of the end effector32, also called end-of-arm-tooling (EOAT). The robot30may be a standard type used in industry for automation tasks, and the end effector32may be configured to grasp the standard basket46of different weights.

The controller42may provide adaptive trajectory planning using the information provided by the vision systems (pick part and place part), as well as predetermined or fixed locations to calculate the best trajectory for the robot to follow in picking and placing the item21. The robot30may be directly controlled by a robot controller60which may handle safety functions, movement control, and control of the end effector32. The controller42may coordinate and communicate with a robot operating system (ROS) driver62. The controller42may also be operatively connected to a machine controller64, such as the controller of the washing machine44. This connection to the machine controller64may allow the system20to know when items may be loaded onto or removed from the machine44. The operative connections between devices may include electrical, radio, optical, light-based, and/or mechanical interconnections and may be wired or wireless.

The robot30may be equipped with touch sensors65, which may include pressurized air pads on the end effector32or gripper, which may allow the robot30to be used without the need for fencing. A touch sensor controller66, such as an air skin controller, may be used to monitor the status of one or more touch sensors65on the robot30, and may be operatively connected to a safety circuit of the robot controller60. In order to allow the robot30to operate without traditional safety fencing, such a touch sensor configuration may require safety performance level E and may require the robot30to be able to react to all humans on the shop floor including operators, visitors, supplier staff, etc. The touch sensor controller66may also be operatively connected to the adaptive system controller42.

After processing by the washing machine44, a camera36may identify a destination location28being a desired stack of baskets46upon a carriage56and which may vary in height as additional baskets46are added to the stack.

The conveyance system20of the present disclosure may provide the following functions: transporting a basket46accounting for variations in the precise special arrangement (x, y, z, roll, pitch, yaw) of both the pick and the place operations; identifying the general source and destination location26,28(x, y, z, yaw) from a stack of one or more baskets46at each location26,28; type identification of baskets46(height, weight, insert feature & geometry); identifying interactions between baskets46(tangled or various other interactions matching predetermined criteria, such as being caught upon another item21and which may be known as easy to take apart); recognizing and reporting a damaged basket46.

The conveyance system20may also provide for identification and information sharing regarding the items21being moved, such as, for example by reading a bar code on the baskets46, and may also identify individual parts22within a basket46, such as by their shape and size in 3-D space, and/or by their positioning within an insert in the basket46. It may provide a mode in which the robot30drains fluid from the carriage56, such as, for example, by moving the carriage56to a designated dumping location and opening a drain valve or by tilting the carriage56.

The conveyance system20may automatically calibrate to account to changes in the environment, such as temperature and/or lighting, and may provide for environmental awareness, such as for crash detection and awareness. In other words, the cameras36of the conveyance system20may detect persons or other hazards, and may direct the robot30to avoid any such hazards. The conveyance system20may provide for increased system reliability and may allow for different sequencing or sorting baskets46, such as, for example, in normal or special operation modes.

The present disclosure also provides a method for automatically moving one or more items21between a structure at a source location26and a destination28using a robot30with an end effector32. The items21may be individual parts22or assemblies of parts22or other things such as a basket46for holding several parts22. The structure may be a bin24for holding parts22. The structure may also be, for example, a cart or a stack or a conveyor for holding or moving parts22or baskets46. The method includes the steps of identifying a part22having a non-fixed location and orientation upon the structure at the source location26using a first vision system34; determining the precise pick location and pick orientation of the part22upon the structure using the first vision system34; and determining the location and orientation of a destination28using a second vision system38. The first and second vision systems34,38may be a combined vision system and may use one or more of the same cameras36. The method also includes the step of performing adaptive trajectory planning to determine the best path40between the source location26and the destination28. According to an aspect, the step of performing adaptive trajectory planning may include the sub-steps of planning a plurality of possible paths40between the source location26and the destination incorporating geometrical information of the robot and source location26and the pick orientation and the destination28which may include the target location and the target orientation; and determining a best path40between the source location26and the destination28by simulating the plurality of possible paths40between the source location26and the destination28. One example of such an active trajectory planning is ROS (Robotic Operating System).

The method proceeds with the steps of picking the item21from the source location26by the end effector32on the robot30; moving the item21along the best path40by the robot30; placing the item21at the destination28by the end effector32on the robot30. The method may also include the step of checking the item21for quality and/or other characteristics by one or more of the first vision system34and the second vision system38.

According to an aspect, the destination28may have a fixed position and orientation. According to another aspect, the destination28may have a varying position, and/or orientation or one which is not fixed in space. According to another aspect, the item21may be disposed loosely or in a fixed position within a bin24at the source location26.

According to an aspect, the first vision34system may be a 2D vision system and the method may further comprise the step of comparing by the first vision system34an image of the item21to a reference image to determine the source location26and the orientation of the item21at the source location26, also called the pick orientation. According to another aspect, the first vision system34may be a 3D vision system, which may be capable of directly determining the source location26and pick orientation. According to an aspect, the system20may be used for two or more distinct pick-and-place operations such as, for example loading and unloading a machine44as shown inFIG. 4.

According to an aspect, the second vision system38may be a 2D vision system and the method may further comprise the step of comparing by the second vision system38an image of the item21to a reference image to determine the location and orientation of the destination28. According to another aspect, the second vision system38may be a 3D vision system, which may directly determine the location orientation of the destination28.