Automated tool change assembly for robotic arm

An automated tool change assembly and method for automatically coupling a robotic end effector to a robotic manipulator. The automated tool change assembly of the present invention provides first and second light-weight mechanical joint members for automated coupling to provide a rigid connection that can include an electrical connection to pass power and signals between the end effector and the manipulator. The connection can also have full pass-through mechanical power. The assembly also includes a tool station for docking an end effector. The tool station can also provide a platform to align tools with manipulators in forming the automatic connection between joint members. The tool station also provides a release bar for manually releasing end effectors from manipulators. Software scripts can connect and disconnect the tool change assembly remotely when attached to a robot.

BACKGROUND OF THE INVENTION

Field of the Invention

Manipulators on mobile robots require specialized end effectors (tools/components) in order to accomplish particular missions. Currently, deployed systems have end effectors designed, built, and installed at the factory. Factory installed tools can only be repaired or replaced in a factory. This limits the effectiveness of the robot to those missions which can be achieved with a single tool. Heretofore, when a new candidate task is identified, the typical response has been to design and build a new robot intended to perform the specific task. Sometimes existing unmanned ground vehicles (UGV) platforms are used, but just as often, a new robot is created to specifically address the task. This has resulted in a proliferation of small UGVs, each performing admirably on tasks within each of its subset of core competencies, but is generally unsuitable for tasks that vary too widely from its essential purpose. It is impractical to expect field teams to carry multiple UGVs, each suited for a specific task. In addition to the strain on the physical resources of the field team (e.g., transportation and maintenance), different robots come with different control schemes. This reduces the ability of the operator to capitalize on the experience and intuition gained from operating previous robots, because the operator cannot rely on the trained reflexes developed while controlling previous robots. In fact, these differing control schemes lead to operator errors and inefficient control.

Another approach has been to design new, more capable robots, but this approach has drawbacks because even if a robot were designed and built to perform all of the tasks currently assigned to UGVs, it would quickly become outdated as new tasks and jobs are identified. Additionally, external variables, such as physical environment, make UGVs designed for one environment wholly impractical for use in another environment, meaning a number of new robot types would need to be designed, tested, and built. Systems with replaceable end effectors are also ineffective because they require a technician and possibly a number of specialty tools. Generally, these changes would require a technician to remove the current tool and to attach its replacement. This may involve physically disconnecting the tool, disconnecting electrical connections, physically attaching the new tool, and hooking up its electrical connections. The system may also require reconfiguring the control software for each specialized tool. Particularly, in time critical applications, such as military or civilian Explosives Ordinance Disposal (EOD), this process is too slow and interferes with missions.

Military and law enforcement groups are increasingly relying on UGVs to perform life-threatening tasks ranging from under car inspection to EOD. As small UGVs, such as Omni-Directional Inspection Systems (ODIS), Talon and Packbot have gained acceptance, the variety of tasks they have been required to perform has increased. Drive systems utilize significant power, unlike industrial robots, these systems are deployed in uncontrolled environments. Driving a system back and forth to physically disconnect a tool is impractical. Operators can stand more than 300 meters from a site. It can take valuable time and resources to drive a robot away in the course of action.

In addition, it takes a robust design to survive the normal working environment for such devices, both during deployment on the mobile robot and when the manipulator and tools are being stored or transported. Mechanical connections must be compliant to minor variations in manufacturing tolerances of mating components, or environmental tolerances which develop when a tool is dropped or bumped against another tool in the toolbox, or caused by the presence of debris, such as dirt and sand, captured from the working environment.

Robotic arms often require specialized configurations to accomplish their particular mission, requiring change in the length of a link in the arm or attaching a different end effector or tool.

Tools that attach to links of the robotic arm that are pivoting or rotating must be able to withstand the large bending movements and torques that result from this.

An object of the present invention is to provide an automated tool change assembly for separating robotic end effectors mechanically from their manipulator arms during deployment, thus allowing unhindered integration of end effectors as the complexity.

Description of Related Art

SUMMARY OF THE INVENTION

An automated tool change assembly for automatically connecting an end effector to a robotic arm having a first joint member having a locking ring, an electrical connector, and a connection plate, and a second joint member having a cylindrical body, a locking plate, an electrical receiver, a locking member, and a locking collar, the locking collar being coaxially aligned with and slidably coupled to the cylindrical body by mating with circumferentially spaced axial extending legs of the cylindrical body with a cavity. The cavity is defined by a carrier plate of the locking collar, further including the locking member extending axially therefrom, the second joint member including springs between the collar and the carrier plate and providing force on the locking collar axially, outward from the body, the locking plate of the second joint member engaging the locking ring of the first joint member, the locking plate and the locking ring having at least one intervening circumferentially spaced tab, which can be engageable in keyed relationship. The tab can include an engagement hole extending axially therethrough. Axially displacing the first joint member into the second joint member can position first joint member electrical connector adjacent electrical receiver. A counter rotation between the first and second joint members slides the locking ring tab of first joint member under the locking plate tab of second joint member, electrically connecting the electrical connector with the electrical receiver and aligning the engagement holes. The spring force on the locking collar can push the locking pin through the aligned engagement holes of the locking plate and locking ring connecting the first joint member to second joint member.

The assembly of the present invention further includes a follower ring, the follower ring having a tab positioned between the locking plate and the locking collar carrier plate, preventing movement of the locking collar by preventing the locking pin from entering engagement holes, the tab further engaging the locking ring prevents rotation of the locking ring past alignment position and locking ring into alignment with a follower ring of the second joint member.

The locking ring and locking plate further includes a plurality of tabs. A key defined by tabs of the locking ring uniquely engages with an opening formed between two tabs of the lock plate providing only one engagement orientation of the locking plate with the locking ring.

The assembly can further include a gear motor housed in second joint member, a mechanically driven tool connected to the first joint member and a self aligning shaft, wherein the self aligning shaft transfers mechanical power from the gear motor of second joint member to the mechanically driven tool of the first joint member.

The self aligning shaft includes a coupler housed in first joint member having a slotted head, a drive shaft having a dowel pin, a compression spring, and a drive hub housed in the second joint member, the hub having a slotted face, a cross slot and a stepped cylindrical bore. The drive shaft engages the cylindrical bore, such that the drive hub cross slot provides axial compliance as translational freedom along the axis of the drive shaft is limited by the length of the cross slot when the dowel pin interacts with the cross slot. The compression spring positioned inside the cylindrical bore and coupled to the shaft provides axial force away outward. Upon rotational alignment, the coupler head engages the drive hub slotted face and the rotational torque is transferred from the drive shaft, through the drive hub to the coupler for powering the mechanical driven tool.

Mating the dowel pin to the cross slot of the hub can be used to provide rotational torque, however, other methods can also be used to pass torque. The engagement of the locking pin with the engagement holes of the locking ring and the locking plate locks three translational degrees of freedom and three rotational degrees of freedom. The electrical receiver includes a pin holder and a pin having a contact surface, the holder for holding the pin in alignment for coupling the electrical receiver pin contact surface to a contact surface of a pin in a holder of the electrical connector.

The electrical receiver pin contact surface couples to an electrical connector pin contact surface. A rotary wiping motion as the first joint member is rotatably connected to the second joint member is formed, the rotary wiping motion used for removing debris from the electrical contact surfaces. The electrical receiver pin comprises a grooved contact surface, the groove forming multiple contact lines when engaged with the pin of the electrical connector. The electrical receiver further includes a flexible member resting in a notched wall of the pin adjacent the pin holder. The flexible member, an elastomer, can provide axial force directed toward the center of the electrical receiver, the force pressing the contact surfaces together during the displacement of first joint member into second joint member. The flexible member of electrical receiver can further provide compliance or resistance to vibration and have a rotation about a connecting member in a bottom of the conductor pin.

A tool station can serve for holding first joint member for positioning the first joint member for automatic engagement or for automatically disengaging the first joint member. The tool station further comprises an engagement member having a body and arms, the arms having an alignment ramp, and track, the alignment ramp providing a tapered opening leading to the track for engaging the first joint member. Engagement pins of the first joint member engage the alignment ramp, the ramp guiding the engagement pins toward the track such that rotational freedom of the first joint member about an axis of the pins provides compliance with height and location parameters of the second joint member during engagement until further movement of the first joint member toward the base provides connection of second engagement pins of the first joint member with the second alignment ramp, the second alignment ramp guiding the pins into the track such that the rotational freedom of the first joint member is eliminated. A release member having a lock ramp and a striker plate is coupled to the engagement member creating an open and close position for release member. The release member further including a spring member creating force pushing the release member to a close position such that a face of the lock ramp aligns with the locking collar of the second joint member when engaged with a first joint member and striker locks the pin of the first joint member inside the two-stage track. The locking collar provides force on the face of the release member lock ramp opening the release member providing an open two-stage track as the striker is moved. Also included is a mount member having legs and an attachment member for coupling the mount member to a surface, the legs coupled to the engagement member.

The track can be a two-stage track having a first and second alignment ramp or one track, depending on the manipulator's degree of freedom. Second engagement pins can have a shortened length, such that the second engagement pins are guided by second alignment ramp into second track adjacent the first track. A lateral guide ramp for guiding lateral movement of the engagement pins is also included. The tool station can be mounted to a robot, guided machine, or unmanned vehicle. The attachment member is rotatably coupled to the surface providing rotational adjustment for aligning the base with the second joint member during engagement or the first joint member pins during disengagement. The base engagement member is rotatably coupled to the legs providing tilt adjustment for alignment of the axis of the first joint member to the axis of the second joint member during engagement.

A manual release lever such that the manual release lever can open the lock ramp of the release member providing a manual operation for releasing the first joint member. The release member can be actuated by a series of electrically controlled motions of second joint member or manually. The engagement is created with a rotation of the locking ring inside of the locking plate to provide clearance of notches. The locking pin further includes a conical surface for mating a chamfered surface on the teeth of locking ring and plate, wherein rotation forces the chamfered members of locking ring to slide under the chamfered edges of locking plate teeth, such that the chamfered edges facilitate engagement of the teeth.

The first joint member and the second joint member are engaged to form an electrical connection operative to transmit images, control signals, activators, identification information, video, USB, TCP/IP, UDP, and CanBus, feedback information. The second joint member is connected to a robot arm. A component connected to the first joint member is included. The component can comprises one of an arm linkage, an arm segment, arm extender, a gripper, a gimble grip, a flexible joint, a tilt table, a dozer, a shovel, a plow, a pan tilt table, a digger, a sensor, a disruptor, a drill, a saw, a cutter, a grinder, a digging tool, or a camera.

A robot end effector automatic-release arrangement comprises a first joint member having a locking ring, an electrical connector, and an end effector connection plate for connecting to a second joint member having a cylindrical body, a locking plate, an electrical receiver, a locking pin and a locking collar, the locking collar being coaxially aligned with and slidably coupled to the cylindrical body by mating circumferentially spaced axial extending legs of the cylindrical body with cavities defined by a carrier plate of the locking collar, the carrier plate further including the locking pin extending axially therefrom, the second joint member including springs between the body and the locking collar providing axial force on locking collar outward from the body such that the locking plate of the second joint member being engageable in keyed relationship with the locking ring of the first joint member, the locking plate and the locking ring having intervening circumferentially spaced tabs, the tabs include engagement holes extending axially therethrough, rotatably aligning and displacing the locking ring into a second joint member providing an electrical receiver receiving the electrical connector. A counter rotation between first and second joint members forces the locking ring of first joint member to slide under and align with the locking plate to connect with the first joint member and rotates electrical connector forming an electrical connection with the electrical receiver. The axial force on the carrier plate of the locking collar pushes the locking pin through aligned engagement holes of the locking plate and locking ring connecting the first joint member to second joint member, a robot component attached to the first joint member, and an electronic component in the robot component for receiving an electrical signal from a control unit of the second joint member.

The assembly further comprises a tool station, the tool station for holding the first joint member or positioning the first joint member for automatic engagement or automatically disengaging the first joint member. A tool station assembly for automatically connecting of a robot component to a robotic wrist is provided. An engagement member having a body and arms, the arms having a first alignment ramp, a second alignment ramp, and a two-stage track, the first alignment ramp providing a tapered opening leading to the two-stage track. Lower engagement pins of a robotic component engage the first alignment ramp during engagement, the ramp guiding the lower pins toward a full length inner track of the two-stage track such that rotational freedom of the robotic component about an axis of the pins provides compliance with height and location parameters of a robotic wrist during engagement. During movement of the lower engagement pins along the full length track upper engagement pins of the robot component engage the second alignment ramp, the second alignment ramp guiding the upper pins into a shortened outer track of the two-stage track eliminating the rotational freedom of first joint member. A release member having a lock ramp and a striker plate, the release member coupled to the engagement member creating an open and close position for release member, the release member further including a spring member creating force pushing the release member to a close position such that a face of the lock ramp aligns with a locking collar of the robotic wrist when engaged with a first joint member and striker locks the pin of the first joint member inside the two-stage track, the locking collar providing force on the face of the release member lock ramp such that release member is moved to an open position providing an opening on the two-stage track as the striker is moved and a mount member having legs and an attachment member for coupling the mount member to a surface, the legs coupled to the engagement member. The tool station can be mounted to a robot, guided machine, or unmanned vehicle.

In addition, provided by the present invention is a method for connecting a robotic tool to a robotic arm, having the steps of a first joint member having a locking ring, an electrical connector, and a connection plate. A second joint member is provided having a cylindrical body, a locking plate, an electrical receiver, a locking pin, and a locking collar, the locking collar being coaxially aligned with and slidably coupled to the cylindrical body by mating circumferentially spaced axial extending legs of the cylindrical body with cavities defined by a carrier plate of the locking collar, the carrier plate further including the locking pin extending axially therefrom. The second joint member can include springs between the body and the locking collar to provide axial force on the locking collar outward from the body. Aligning the locking ring of the first joint member in keyed relationship with the locking plate of the second joint member, the locking plate and the locking ring have intervening circumferentially spaced tabs, the tabs include engagement holes extending axially therethrough. Displacing the first joint member into second joint member such that the first joint member electrical connector is positioned adjacent electrical receiver, rotating first joint member within second joint member to slide the locking ring tabs of first joint member under the second joint member locking plate tabs, electrically connecting the electrical connector with the electrical receiver; aligning the engagement holes such that the axial spring force on the locking collar carrier plate pushes the locking pin through the aligned engagement holes of the locking plate and locking ring connecting the first joint member to second joint member. Rotating the locking collar, whereby the intervening teeth of the coupler is rotated into engagement with teeth located circumferentially about the locking collar, wherein the locking collar rotation forces the teeth of locking collar to slide over the teeth of coupler. The coupler is clamped into engagement with the first joint member; and engaging a retaining pin to lock the collar to the first joint member.

The method further includes terminating displacement of the first joint member into second joint member when the pin engages locking wall.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The automated tool change assembly of the present invention provides first and second light-weight mechanical joint members for automated coupling. The automated tool change assembly provides a rigid connection, for connecting an end effector to a robotic manipulator. The automated tool change assembly can include an electrical connection to pass power and signals between the end effector and the manipulator. The connection can also have full pass-through mechanical power. End effectors for attaching using the automated tool change assembly can include components such as a retrievable delivery device, gamble grip, dozer, shovel, tilting tools, plow, drills, saws, cutters, grinders, sensors, camera, disrupter, arm extenders, arm linkages, digging tolls, and pan-tilt table. One skilled in the art will recognize this list is not exhaustive and the use of other types of robot components with the automated tool change assembly of the present invention is possible.

A further object of the present invention is adaptability. End effectors can operate seamlessly as the automated tool change assembly provides electrical connectors for transmitting signals between controllers and processors, since they can be plug-n-play. In one embodiment, an operator control unit can identify a current end effector and current controller by reading an embedded chip jumper, or resistor in the end effector and can pass electrical signals to control the end effector through the automated tool change assembly of the present invention. The embedded chip can obtain a unique identifier for that particular end effector. Therefore, when a new end effector is attached using the automated tool change assembly of the present invention, a unique identifier for the tool can be read and passed to an onboard or external computer system that can analyze the signal to identify the present end effector. The operator control unit can transmit messages to the processor on the arm or to operate the end effector accordingly.

With reference toFIG. 1a, a first joint member, tool base assembly2and second joint member, wrist assembly4are shown with the tool base assembly2positioned to engage with the wrist assembly4. The tool base assembly2can have a lock ring6, electrical connector8, and a conductor plate10. Tool base assembly2can be mounted to a number of different end effectors. The wrist assembly4can have a lock plate12, a follower ring14, and an electrical receiver16. The wrist assembly4forms a cylindrical body having a cavity18in the middle for receiving a tool base assembly2. When the tool base assembly2is displaced into the wrist assembly4, a connection can be made between them. The interaction of the parts of tool base assembly2and wrist assembly4is discussed in detail below.

With reference toFIG. 1b, a robot arm shows the degrees of freedom that the arm provides. Wrist assembly4can be mounted to the end of a four degree freedom arm, which includes yaw, boom, and stick motion, as well as wrist rotation, which is concentric to the axis of the assembly.

With reference toFIG. 2a, in addition to lock ring6and electrical connector8, a tool base assembly2can also have a connector plate32and lower engagement members, track pins36a,36band upper engagement members, track pins37a-37d.

With reference toFIG. 2b, an exploded view of the tool base assembly2and its member parts including lock ring6, electrical connector8, and conductor plate10can have conductor pin20aand a short conductor pin20b. These pins20a,20bare positioned in cavities22a,22bformed about the surface of the electrical connector8. The conductor pins20a,20bcan be mounted on the conductor plate10with pins24a,24bconnecting with the conductor pins20a,20bthrough holes26a,26bof the conductor plate10.

With continuing reference toFIG. 2, tool base assembly2can further have a cylindrical body, electrical casing28coupled to the conductor plate10using screws (not shown) inserted into holes30a-30d. Electrical casing28can be connected to a connector plate32. Connector plate32has a cavity therethrough and screw holes38a-38dfor coupling with electrical casing28. Connector plate32has a set of holes34a-34dfor attaching lower track pins36a,36b, and upper37a,37binto them. Lower track pins36a-36band upper track pins37a-37bcan have threaded heads or attached using other fastener methods known in the art. When fastened to connector plate32, the pin body remains external from the holes for coupling with a tool station400, as described hereinafter. The plate32can be coupled to a box44with holes40for receiving threaded members (not shown) into holes46of box44. Box44can hold a microcontroller42. Microcontroller42can store programming instructions and transmit and receive electric signals to other processors or drives to activate control of the end effector that is being used on tool base assembly2.

With reference toFIG. 3, an exploded view of the wrist assembly4and its member parts including the lock plate12, follower ring14, and electrical receiver16is shown. As shown inFIG. 1, wrist assembly4can have a continuous cavity18running the length of wrist assembly4and passing through each member of wrist assembly4. Wrist assembly4can have a body, lock hub52. Lock hub52fastened to lock plate12and holding follower ring14. Lock hub52can have a cylindrical shape with a set of legs54a-54dcircumferentially placed, extending axially inward and intertwined with carrier plate56. The carrier plate56can have tabs90acircumferentially spaced and extending radially outward. Each tab90ahaving a set of respective holes59a-59dand94. Holes59a-59dare for holding pins58a-58d. Holes94are for coupling to a lock collar60. Lock collar60, a cylindrical body having a set of tabs92positioned circumferentially and radially facing inward on the inside of the lock collar60can fasten to corresponding tabs90aof the carrier plate56. Legs54a-54dof lock hub52can pass through cavities formed between the connector of collar60and the carrier plate56. The carrier plate can have lock member fastened thereto, for example, a set of lock pins58a-58dmounted to carrier plate56. The pins58a-58dcan engage holes57of the lock hub52and coinciding holes of lock ring6, lock plate12, and follower ring14, as described below.

With continued reference toFIG. 3, electrical receiver16can have conductor pins62a,62binserted into slotted surfaces64a,64bformed on an internal wall of electrical receiver16. The pins62a,62bcan be held in place by a conductor plate66having holes68a,68bthrough which a pin70can pass and further insert into an axial hole (not shown) in the bottom of conductor pin62a,62b, giving it support and holding it in position. One skilled in the art will recognize any number of conductor pins can be used in the housing depending on the type of electrical connections needed.

A cylindrical grooved housing72can be coupled to the conductor plate66holding a motor74for passing mechanical power can be coupled thereto and held in position by a plate82jointly coupled to housing72and motor74. Housing72can provide a mechanical power take off (PTO) self-aligning drive shaft at least partially inside. The PTO can have a driveshaft76, a compression spring78, and a drive hub80and is described in detail hereinafter. Plate82can hold the PTO from moving and it is connected to the housing72. Holes84a-84dof plate82can receive threaded members (not shown) to fasten plate82to housing72. Holes86a-86dof housing72can receive threaded members passing through holes88a-88dof conductor plate66and into holes (not shown) on locking collar60. Members96fasten the lock plate12to lock hub52. One of skill in the art will recognize that threaded members can include screws, pins, or other fasteners.

InFIG. 4a, the lock ring6and lock plate12are shown aligned ready for engagement. The lock ring6can have tabs120a-120d. The tabs120a-120dcan form a clover leaf configuration. In one embodiment, one of the tabs, tab120ccan define a key tab having a slightly larger size than tabs120a,120b,120d. The tabs120a-120ddefine notches122. The tabs120a-120dcorresponds to tabs100a-100dof lock plate12. The lock ring6further includes holes124a-124d,126a-126d. The tabs120a-120dof lock ring6can have chamfered edges128. The lock plate12can have tabs100a-100d, also defining notches102a-102dbetween the tabs100a-100d. The tabs100a-100dcan have a hole104a-104dtherethrough. The lock plate12can also have chamfered surfaces108about the rim of the tabs120a-120dand notches102a-102d. The chamfered surfaces108and128can facilitate the mating of lock ring6and lock plate12. When mating, key tab120censures the tabs120a-120dof the lock ring6only mate with tabs100a-100dof lock plate12in one position, ensuring the tool base assembly2is aligned properly with the wrist assembly4for displacement into the wrist assembly4.

With reference toFIG. 4b, displacing lock ring6axially into the lock plate12positions the tabs120a-120dwithin the notches102a-102dformed by tabs100a-100dof lock plate12. The key tab102ccan have a special size or shape where it is only fitting into the key notch102cof lock plate12.

With reference toFIG. 5a, the tool base assembly2, after alignment, can be displaced into the wrist assembly4. The wrist assembly4limits the amount of displacement of the tool base assembly2as the electrical receiver16mates with electrical connector8and the axial movement of the tool base assembly2into wrist assembly4is stopped. After axial movement of tool base assembly2is stopped, rear surface130of lock ring6is inside lock plate12of the wrist assembly4.

With reference toFIG. 5b, the lock ring6is positioned inside of the lock plate12and no further axial movement of tool base assembly2can take place.

With reference toFIG. 6, when the automated tool change assembly is fully engaged with the lock ring6as the tool base assembly2is rotated, the tabs120a-120dof the lock ring6are rotated and forced underneath the tabs100a-100dof lock plate12. Rotational force on the lock ring6also causes the rotation of the follower ring14, moving the tabs on the follower ring14to coincide with the notches102a-102dof the lock plate12.

With reference toFIG. 7, when the lock plate12and lock ring6, align holes104a-104dof lock plate12align and with the respective holes124a-124dof lock ring6. With reference toFIG. 8, the position of lock ring6is inside lock plate12.

With reference toFIG. 9a, when lock ring6and the lock plate12are aligned, pins58a-58dof carrier plate56are free to move into the holes104a-104dof the lock plate12and the holes124a-124dof lock ring6. With reference toFIG. 9b, springs180can be positioned between the plate66and lock collar60. The pins58a-58dof carrier plate56have an axial force placed on them by springs180in the locking collar60, causing the pins58a-58dto move into the holes104a-104dand124a-124dwhen the lock plate12and lock ring6are rotated into complete alignment relative to each other. The wrist assembly4and the tool base assembly2lock when the pins move into the holes, locking three translational degrees of freedom and two of the rotational degrees of freedom between the wrist assembly4and the tool base assembly2. The lock ring6includes a chamfered surface134on the inside of the holes. A conical shoulder132of the pins58a-58dwill rest against surface134when fully engaged as described hereinafter.

With reference toFIG. 10, when the tool base assembly2and the wrist assembly4are rotated into the alignment position, the lock pins58a-58dand the carrier plate56slide axially toward the holes102a-102d,124a-124dto create a double-shear pin joint in the four locations where the holes102a-102d,124a-124dare aligned. Lock pins58a-58dcan be slightly rounded, tapered, or sloped on the leading edge to provide a self-guided action to tolerate misalignment between the wrist assembly4and the tool base assembly2.

With reference toFIG. 11, when lock ring6is engaged with lock plate12, pins58a-58dmate with holes57of lock hub52. In addition, the pins58a-58dcan have a smaller diameter than the holes120a-120dof lock ring6and holes102a-102dof the lock plate12. This smaller diameter is utilized for tolerating debris as well as manufacturing variations. The conical shoulder132of pins58a-58dwedges against chamfered surface134of the lock ring6. Locking collar springs apply axial force on the conical shoulder132of pins58a-58d, pushing the shoulder132into the chamfered surface134, allowing friction and spring force to provide sufficient force to keep pins from popping out when side force occurs. The angular slope of the conical pin is steep enough that side force will not pop out the pin and not so steep that it self locks, in one embodiment defining a 45° angle. This movement provides a self-centering of the pins58a-58din the hole124a-124d, aligning the lock ring6and removing backlash between the tool base assembly2and the wrist assembly4. Component parts of the automated tool change assembly are manufactured to tolerate debris and manufacturing variations. As the automated tool change assembly is designed to form connections between loose fitting parts, the tapered engagement of each lock pin58a-58dleaves clearance for debris.

With reference toFIG. 12, the lock ring6can have chamfered surfaces128to ease a chamfered surface136a-136d. Similarly, lock plate12can have chamfered surfaces108. Chamfered surface136of lock ring6coincide with chamfered surfaces138a-138dof lock plate12and facilitate mating of the surfaces as the tool base assembly2is displaced into the wrist assembly4. The chamfered edged surfaces136a-136dand chamfered surfaces138a-138dmeet and help the lock ring6slide past the lock plate12. Additional chamfered surfaces can ease the rotational resistance when the lock ring6and lock plate12are rotated against each other, causing the lock ring6to slide under the lock plate12.

With reference toFIG. 13a, the lock ring6is shown aligned with follower ring14of wrist assembly4. The follower ring14can have members tab140a-140dforming notched surfaces142a-142dhaving a detent144a-144dtherein. The detent144of follower ring14can have a ball detent assembly which keeps the follower ring14in the disengaged position until a tool is inserted. A member (not shown), such as a ball or tab can be formed on the lock hub52for mating with the detents144a-144d.

With reference toFIG. 13b, wrist assembly4is shown unengaged. With reference toFIG. 13c, a cross section of follower ring14of wrist assembly4a long lines A-A ofFIG. 13b, showing a slot152formed in follower ring14for mating with a member, pin150fastened to lock hub52. The combination of pin150with slot152can limit the rotation of follower ring14during engagement and thereby limit the rotation of the wrist assembly4counter to the tool base4. For example, rotation can be limited to 45° in an embodiment having four tabs on lock ring6of tool base2. Other embodiments are envisioned having a different number of tabs on the lock ring6, lock plate12, and follower ring14where a different rotational angle is needed, slot152can provide such an angle.

With reference toFIG. 14a, the follower ring14is in the open position and the lock ring6has been displaced into the follower ring14. In the open position, the lock pins58a-58dof the locking collar14is prevented from sliding into the locked position (seeFIG. 12). This prevents the locking collar60from opening, especially when no tool base assembly2is inserted. By blocking the pins58a-58d, the locking collar60also remains open, the springs having a potential to move the collar60when open. The user of the automated tool change assembly can move the follower ring14by placing the tool base assembly2into the wrist assembly4and rotate it until the locking collar60slides into the locked position.

With reference toFIG. 14b, when the lock pins58a-58dare pressing against the closed follower ring14, the pins58a-58dare prevented from moving into the engagement position.

With reference toFIG. 14c, when the lock ring6has been rotated, it causes the rotation of the follower ring14into the closed position. In the closed position, the pins58a-58dare freed to move through holes144a-144dof follower ring14. The follower ring14can limit the rotation of the tool to a 45 degree rotation required to engage and disengage the tool base assembly2from the wrist assembly4. This keeps the keying assembly aligned within the wrist assembly4.

With reference toFIG. 15a, a conductor pin mounting assembly can have a conductor block200having holes for receiving conductor pins placed about the conductor block200. A hole201can receive a conductor pin212having a cross hole214. On the back210of the conductor block200, hole201can include a slot202. An end of conductor pin212having cross hole214extends from the back210of conductor block200. Cross hole214receives a roll pin206, which is seated in the slot202of hole201. The roll pin206mates with the slot202of hole201. A fiberglass plate208can be inserted on top of conductor block200once the roll pins204have been fastened. The fiberglass plate208is an insulating plate that is bolted in place over the roll pins204, maintaining the roll pins204position. The rotational position of the roll pins204is aligned and the roll bar206acts as a pin joint to allow the roll pins204to pivot about the axis of the roll pins204. This method is also useful for quick disassembly.

Returning toFIG. 15a, the conductor pin212further includes an elastic member216placed between the surface of the conductor block500and the conductor pin212. The elastic member216provides force directed toward the center axis of the wrist assembly4to press the contacts together upon the tool base assembly2displaced into the wrist assembly4. The elastic member216also provides compliance, allowing the pin212to partially rotate about the axis. During engagement, the rotation of pin212in connection with the electrical receiver at condition510of tool base assembly2causes contact surface218to come in contact with a contact surface of a corresponding pin.

With reference toFIG. 16, the electrical receiver conductor block200can mate with an electrical connector conductor block230. Conductor pin212of conductor block200can have contact surface218and elastic member216engaged between the rear surface. The contact surface218of pin212is shown having a detent222forming a first contact point224and a second contact point226when rotated, sweep against a conductor pin220of the connector218. A conductor pin220of conductor block230contacts the detent surface222of conductor pin220forming electrical contacts at two points224,226due to the detent226of pin212. When pin220of the tool base assembly2comes into contact with the pin212of wrist assembly4during a rotary motion, the pins220,212provide a wiping action against each other to clean and dislodge debris. The opposing pins provide counter forces, therefore, the contact system does not contribute any tool insertion force and the load path is contained within the conductor block200, so the arm only needs to provide a small torque to rotate the contacts into engagement. The elastic member216provides resistance to force and provides compliance against vibration, electrical noise, and low tolerances.

With reference toFIG. 17a, a mechanical power take off (PTO) self-aligning drive300can have drive shaft76, compression spring78, and drive hub80positioned in the wrist assembly4. A coupler310can be positioned in the tool base assembly2. PTO300can be used to mechanically couple driven tools connected using the automated tool change assembly with a motor residing within the wrist assembly4. The drive shaft76is coupled to the output of a motor using a slip fit bore and a set screw or other clamping method known in the art. The drive shaft76can have a stepped pilot shaft302with a stepped portion304and a cross hole (not shown). The drive hub80can have a cylindrical bore305ahaving a stepped surface305band a slotted face306with a vent308to prevent build up of a vacuum. The drive hub80can receive the compression spring78and stepped pilot shaft302of drive shaft76within the bore305a.

With reference toFIG. 17b, a dowel pin312is inserted through cross hole314of drive hub80and a cross hole (not shown) in drive shaft76holding the shaft76and spring78within the hub80. Five degrees of freedom are constrained by the dowel pin312. The only free degree of freedom is translation freedom along the axis of the drive shaft76. The translation freedom is only limited by the length of the cross hole314as the dowel pin312moves therein. The dowel pin312transfers torque about the axis of the drive shaft76and slides along the slot314of hub80to provide axial compliance. The compression spring78is captured in-between the drive shaft76and the drive hub80to provide an axial force toward the tool base assembly2. The axial force provides an engagement force to engage the hub80to coupler310, having a slotted face306which mates with a slotted surface306of the drive hub80. The slotted head316of coupler310mates with slotted face306of drive hub80. The coupler310can mate with an end effector connected to tool base assembly2. The coupler310provides a self-alignment, which can prevent binding during manual and automated tool change.

With reference toFIG. 17b, coupler310is shown in the disengaged position. As it is rotated, the slotted head316of coupler310is inserted into a slotted face306of hub80, it becomes engaged as shown inFIG. 17c. The movement of dowel pin312within cross hole314is due to the spring force acting on hub80causing axial movement into engagement with coupler310. One skilled in the art would recognize that other mechanisms to transfer torque between the drive shaft and drive hub could be used.

With reference toFIG. 18, the automated tool change assembly further includes a tool station400. The tool station serves the function of holding the tools when not in use by an arm. In addition, tool station400can provide correct positioning for tool base assembly2during engagement. The tool station400can also interact with the wrist/tool assembly for disengagement. The tool station400can have legs402, arms404, and lock ramp406. The tool station400can be mounted on the surface of a robot in a space relative to the arm. The mount can provide rotational adjustment to allow the center plane of the tool station400to align with the wrist assembly4from the top. One tool station400is used for each tool base assembly2on a robot. Any number of tool stations400can be used on a robot, depending on the space available on the robot.

With reference toFIG. 19, the tool station400can have legs408a,408bhaving holes412a,412band414a,414b, respectively. A block410is provided for mounting to a surface, such as a robot unmanned vehicle. A bore411of block410can receive a fastener for fastening to a surface, holes416a,416b,418a,418bof block410can be coupled to holes412a-412band414a-414bof408a,408bwith a fastener, such as a screw or pin. Legs408a,408bcan have an arched top420a,420b, arched adjuster holes422a-422b, and arched adjuster holes424a-424b, and a further hole426atherethrough. This adjustment provides capability to align the tool base assembly2axis to the axis of the wrist assembly4from the side. The holes422a-422b,424a-424b426a-426bcan be used to fasten legs402to arm member404, as shown inFIG. 18. Tool station400can have arms430a,430b, having holes432a-432b,434a-434bfor connecting arms430a-430bwith the adjuster holes422a-422b,424a-424b, and holes426a-426bof legs408aand408b. The screws can be used to adjust the angular position of the arm404about the axis formed by holes426a-426b. Arm430a-430bcan further have a two-stage track436a-436b(not shown).436a-436bhas ramped surfaces438a-438b,440a-440b, ramps438a-438bformed on an outer surface of ramps440a-440b. The ramped surfaces438a-438bact as ramps with respect to pins36a-36band37a-37bof tool base assembly2(seeFIG. 2), guiding the tool base assembly2into engagement with the tool station400as the arm404lowers the tool base assembly2into the tool station400. The shortened length of ramps438a-438bdelays the engagement of the upper pins37a-37bof tool base assembly2. The upper pins37a-37bcan also have a shorter length, thereby not engaging with ramps440a-440b. Guides442a-442bprovide for lateral compliance of the lower pins36a-36bwith the tool station400. Block444includes holes446a-446b,447a-447b,448a-448bholding the arms430a-430btogether.

With continuing reference toFIG. 19, plates454a-454bare provided having a striker458a(not shown) and458bpositioned on an internal surface extending outward having a ramped surface459on one side thereof. The plates454a-454bcan be attached by a hollow cylindrical bar461coupled to holes461a-461b. The plates454a-454bcan also have a manual release460attached with holes462a-462band464a-464bto holes463a-463b, respectively. Holes466a-466band468a-468bare provided for fastening plates454a-454bto the arms404.

With reference toFIG. 20, the alignment ramps438a-438band440a-440bcan provide an opening leading to the two-stage track436a-436b, guiding engagement pins36a-36band37a-37b. The degree of freedom of the engagement pins36a-36and37a-37bis restricted after entering the ramps. Movement of the lower pins36a-36balong track436provides precise guidance of the tool base assembly2relating to the tool station400regardless of what the wrist assembly4is doing. The ramp guides the lower engagement pins36a-36bduring stages1-4of engagement. The full length of two-stage tracks436a-436b, and as it does, rotational freedom of the tool base assembly2about the axis of the lower pins36a-36bprovides compliance with height and location parameters of the wrist assembly4during engagement. The rotational freedom is unrestricted during movement of the lower pins36a-36bdown the track436a-436bduring 95% of the movement. Further movement of the tool base assembly2into the tool station400provides connection of the second upper set of engagement pins37c-37dwith the second alignment ramp438. The second alignment ramp438bguides the upper pins37c-37dduring engagement steps1-4into a shortened outer track of the two-stage track436, eliminating rotation freedom of the tool base assembly2. As the lower pins36a-36benter and move down the track436during stages1-3of engagement, they meet the striker458, causing the striker458to resist the pins36a-36bduring stage3of engagement. As the lower pins36a-36bcontinues from stage3of engagement, they move the striker458downward against spring force transferred from manual release bar460to a member462of lock ramp406. When the pins36a-36bare clear, the spring force causes the striker458to return to the closed position at stage4of engagement.

With reference toFIG. 21a, the pin36a-36bcan move over the striker458. When pins36a-36bare positioned over the striker458, the striker458is lowered to its original position. Pin37ais still rotationally free. With reference toFIG. 21b, the striker458is completely open to allow the pins36a-36bto pass. Pin37ais not restricted rotationally.

With reference toFIG. 21c, the pins36a-36dare locked behind the striker458when the striker458returns to its initial position and the upper pin37a-37bare inside the track436.

With reference toFIG. 22, a handle on the side, bar460provides manual operation for an operator to open the lock ramps and remove the tool base assembly2from the tool station400.

With reference toFIG. 23, plate454is shown adjacent the wrist assembly4. The plate454of lock ramp406can have a face470, which can be aligned such that the wrist assembly4can rotationally engage tool base assembly2. The axial force from the lock collar60moves the lock ramps406into the open position during the automated tool pick, thereby opening the striker458.

With reference toFIG. 24, during parking of a tool, a slanted face472, of lock ramp406, can have a slope automatically providing the penultimate step in the disengagement process to slide back the lock collar60, thereby releasing the pins58a-58dof the wrist assembly4as it is moved into place to park a tool base assembly2into the tool station400. Parking also moves the locking ramps406into the open position as the force of the locking collar60pushes on the lock ramp406. To completely disengage, a final rotation of the wrist assembly4counter to tool base assembly2can be given. When the wrist assembly4is removed, the striker458is free to close, locking the tool base assembly2to the tool station400.

With reference toFIG. 25, a method of connecting a wrist assembly4with a tool base assembly2begins at block500by providing a wrist assembly4and tool base assembly2. The tool base assembly2can be engaged with a tool station400, as shown inFIG. 22. At step502, the wrist assembly4is prepared by displacing it toward the tool base assembly2. In one embodiment, approximately one inch away. When the wrist assembly4is positioned proximate to the tool base assembly2, as shown inFIG. 1, the wrist assembly4can be displaced axially into the tool base assembly2at block508. While the wrist assembly is being displaced toward the tool base assembly2, at condition510, this continues until a full engagement depth has been reached. When full engagement depth has been reached, the wrist assembly4has engaged tool base assembly2and the tool base assembly2will have a lock ring6inside of the wrist assembly4, as shown inFIG. 5a. At block514, tool base assembly2is rotated relative to the wrist assembly4. As the locking ring6of the tool base assembly2rotates at block514, the locking ring6applies a rotational force on the follower ring at block520. At block522, the electrical pins of the electrical connector8and electrical receiver16create a sweeping motion, thereby cleaning contacts of debris and moving into contact at block522. At block224, the locking collar60is released. The locking ring6has moved the follower ring14rotationally opening a passageway to aligned holes of the locking ring6, locking plate12, and the lock hub52, as shown inFIG. 9. Once rotation is completed at block514, engagement holes of the locking ring6and locking plate12are aligned at block526. At block528, the locking collar spring forces axial displacement of the pins58a-58dinto aligned holes of the lock ring6, lock plate12, and lock hub52. Engaging the drive shaft76at block530, the PTO coupler310forms a mechanical power pass thru. The contact surfaces of the conductor218,220are engaged at block532, as shown inFIG. 16. At block534, a communication signal can be transmitted from the onboard microprocessor of the tool base assembly2to the processor of the arms404or further down to a computer processor housed on the robot. At block536, the wrist assembly4and tool base assembly2are moved off of the tool station track436. At block538, the wrist assembly4and tool base assembly2disengages with the tool station400.

With reference toFIG. 26, a method of disconnecting a tool base assembly2from a wrist assembly4includes either a manual method or a method automatically using the tool station400. The disconnection begins at block600with a connected tool base assembly2and wrist assembly4. The wrist assembly4and tool base assembly2are positioned adjacent to a holder at block602, as shown inFIG. 24. Next, the tool station400is aligned rotationally and the tilt is adjusted to receive the wrist assembly4at block604.

With reference toFIG. 28, the robot160can have a two degree freedom arm162. The tool station400provides flexibility to line the arm162up with the automated tool change assembly164by positioning the horizontal plane of the tool station assembly400in the horizontal plane of the arm162. For alignment of the tool, when the tool station400is positioned around robot160, the lateral center plane of the wrist plane can be positioned coincident with the center plane of the tool station400by rotating the legs of the tool station400appropriately.

With continuing reference to, block604can be done before beginning the method to provide proper station configuration. At block606, the wrist assembly4is driven electronically (or manual placement) onto the tool station400. This movement causes the slanted face472to contact the locking collar60. Moving the locking collar60onto slanted face472when collar60is locked, forces the collar60to open, causing the pins58a-58dof the locking collar60to move out of lock ring6and lock plate12. At block610, pins of the tool base assembly2slide into the alignment ramps310. At block612, the alignment ramps310guide the pins into the two-stage track436, as shown inFIGS. 21a-21c. The lower pins move along the track436at block614. At block616, rotational freedom about the axis of pins36a-36bfacilitates placement of the tool on tool station400. Contacting the striker458, pins36a-36bcause the striker to open, allowing the pins to enter further track436at block618, moving the upper pins320further onto the ramp, places the lower pins in a position adjacent the lock ramps, guiding them into the track436. At block622, when the pins37a-37bhave entered the track436, all degrees of freedom is restricted. Pins58a-58dis finally free of the tool base assembly2. With release of pins58a-58d, the wrist assembly4can be rotated, automatically or manually. The wrist assembly4is rotated automatically using a motor inside the wrist assembly4at block626. In one embodiment, the wrist assembly4rotates 45 degrees to open. At block628, the locking collar60is blocked by follower ring14. At block630, the striker458is closed, locking the tool base assembly2into place, as shown inFIG. 21c. At block632, the wrist assembly4is disconnected, as shown inFIG. 22.

The automated tool change assembly can be connected and disconnected using programmed scripts processed by a computer processor on a robot computer and transmitted to drives throughout the arm, wrist, and can include the end effector.

A CanBus can provide communication channels between the operation control unit OCV, arm, and end effector to transmit in addition to supplying power signals. The signals can be messages that instruct drives that control components. The automated electronics need one drive for each motor and can have the motor driver in an arm or an end effector. The motors can be smart motors, monitoring details regarding behavior of each tool. Controllers can quickly configure the drives based on feedback. The motor can have sensors to feed back to the drive information about what it's doing. The CanBus supplies the power and the electrical connections and can limit the supply of power or can be told to limit the supply of power to accommodate the motor sensors. The power supply can be a 48 volt vehicle battery, however, this is not a limiting feature of the invention, supplying 20 amps to the arm. However, one skilled in the art will recognize other electrical supplies can replace the battery.

With reference toFIG. 27, an arm100receives information sent throughout the manipulator from operator control unit702using Joint Architecture for Unmanned Systems (JAUS) to transmit a message704. The motor controller can be coupled to an arm or alternatively, can be positioned closer to the end effector and can receive power through the CanBus. The motor controller can control a motor, and alternatively, can control the brakes on the motor. The motor controller can act like an amplifier.

Program code can provide instructions to the components to complete an action. Using motor currents, a processor can determine proper actions based on conditional logic within a program. Program code can also be used to control processors to cross check absolute sensors in motors. When behavior is outside a range, steps can be repeated until the proper range is reached. Scripts can provide a series of predetermined steps operating the arm and end effector. A microprocessor, sensors, and an onboard computer chip can be used to move end effectors to a specific position. Error messages can be sent to the operator as they occur.

With continued reference toFIG. 27, the arm computer706receives the instructions from the OCU702. A translator712translates the instructions, doing computation710to determine position and velocity of joints having an arm. Each joint may possibly have its own ebox. Next, the arm computer706sends to the translator712program code to translate instructions for sending to components over the CanBus, USB, or serial connection. Each CAN translated instruction provides a message719for identifying an outcome parameter in a grid716, such as a movement of an arm or torque of a motor. The instructions can be used to control motor drive712or tool computer720. Tool computer720transmits to a tool, such as gripper722and also is capable to read the tool ID Board.

With continuing reference toFIG. 27, operation control unit702can have an attach tool button for attaching a tool, such as a gripper to the robotic manipulator. When a user presses the attach tool button, a message704is sent to the arm706and is translated at the translator708. The message704can trigger a series of steps to attach a tool. In the script, the first step is to move the arm of the robot to a safe altitude and joint space. This involves moving the arm straight up until the arm is high enough for safe clearance. Next, the arm is positioned near the tool station that is used to hold the tools a safe position away from the robot deck. A database724can be searched by the computation module710to acquire the station ID the tool station holding the gripper, or if another tool is being used, it would search for the station ID for that tool. After the computation module locates the station ID, it determines a calibration point, the point used for all measurements, by looking up in the database using the station ID. Next, the computation710determines the important points based on the calibration point. The arm can then move to a pre-engaged point in joint space near the station. The wrist can be twisted to a pre-engage angle, for example, approximately 45°. Actions are accomplished by sending messages via translator712to the different motor drives718and tool computers720, attached to the tools, such as gripper722. Motor current can be limited causing the engagement force to be less than full force. The arm is driven in Cartesian mode along the engagement vector. The arm continues to be driven along the vector until the tool is connected. Additionally, if a time limit or a final position is not reached, the arm movement can be stopped because the time and/or position indicate error. The scripts can also use motor current and position information received from drives. If motor current is exceeded, or if a position error is determined within a range, arm movement can be stopped. After the arm is connected, the wrist is twisted to what is an over-engaged angle. The arm computer can determine that the wrist is engaged if the tool ID boot-up is accomplished. In addition, the angle of engagement can be tracked. If the motor current exceeds a limit, for compliance, the wrist is stopped from twisting. When the software detects and knows that the tool has been attached, the wrist is twisted back to engagement angle, therefore it is twisted to center the wrist. The arm computer706calculates angles to determine the proper position of the engagement. The arm is driven to a post-engagement point in Cartesian mode after it is engaged by sliding up and out of the tool station. The collar will start to snap down, causing the engagement pins to move into place. The arm can then be driven to a safe point. Next, the OCU702of the arm computer706can determine exactly which tool is engaged by checking the tool ID information to reconcile that the proper tool was loaded. Based on the tool ID, the motors are configured and the variable current or any current is determined. The PTO motors are configured based on the tool ID and any motor drives on the tool are initialized. The station ID is stored in memory or a database in order to determine where to return the tool when the present job is completed. Finally, the tool information is sent to the OCU702so that the OCU can determine which tool is attached to the manipulator. The OCU702can then initialize the operation settings, which are screen controls, operator controllers, and joy sticks for the new tool. At this point, the operator can control the new tool by sending commands from the operator control unit to the arm computer706.

Additional procedures are available to perform other functions, such as calibrating tool stations. The tool station can be calibrated by placing a tool in the station and then driving the arm to a calibration point. A saved calibration point button can be programmed on the operator control unit to save the actual calibration point that is determined. This step sends a message to the arm computer706to store the current calibration point in database724. The station ID is also stored for the specific calibration point and the next time that tool is needed, the computer can retrieve the information from the database.