Patent Grant
11404183
The present invention relates to the field of wire harness fabrication, and in particular to the assembly of wire bundles of varying configurations on harness form boards (hereinafter “form boards”). The terms “wire bundle” and “wire harness” are used as synonyms herein.
Vehicles, such as large aircraft, have complex electrical and electromechanical systems distributed throughout the fuselage, hull, and other components of the vehicle. Such electrical and electromechanical systems require many bundles of wire, cables, connectors, and related fittings to connect the various electrical and electromechanical components of the vehicle. For example, a large aircraft may have over 1000 discrete wire bundles. Often these discrete wire bundles are grouped into assemblies known as wire bundle assembly groups, which may comprise as many as 40 wire bundles and 1000 wires. Wire bundles are typically assembled outside of the aircraft.
In accordance with a typical method for assembling wire bundles, form boards are used to stage a wire bundle into its installation configuration. Typically each wire bundle of a given configuration fabricated in a wire shop requires a customized form board for layup. The form board typically includes a plurality of fixed form board devices which together define the given wire bundle configuration. During wire bundle assembly, the constituent wires are routed along paths defined by the positions and orientations (hereinafter “locations”) of the fixed form board devices. However, the precise position of a particular wire, as that wire is passed through or around a form board device, may vary in dependence on the particular bunch configuration of already routed wires within or in contact with the same form board device.
Robots are used to assemble electrical wire harnesses using wire segments cut to length and configured prior to bundling. For example, a layup robot may be used to insert one end of a wire into a connector on a form board and then route the wire through the fixed form board devices to control shape. The second end of the wire is then inserted into another connector.
Robots may be manually trained or programmed for each different harness configuration. A method is needed for managing robot motions for routing wires on harness form boards that does not require significant manual setup or programming for each different harness configuration.
The subject matter disclosed in some detail herein is directed to methods and apparatus for robot motion control and wire dispensing during automated routing of wires onto harness form boards. The robot includes a manipulator arm (a.k.a. robotic arm) and a wire-routing end effector mounted to a distal end of the manipulator arm. The wire-routing end effector is configured for dispensing and routing a wire along a path through form board devices mounted to a harness form board. The wire-routing end effector is moved along a planned path under the control of a robot controller. The robot controller is a computer or processor configured with executable computer code stored in a non-transitory tangible computer-readable storage medium. An end effector path is provided with a set of processes that enable rapid, and even fully automatic, development of robot motion controls for routing wires on harness form boards.
Typically, wires are each cut with excess wire length. Each end of the wire is processed (stripped, crimped) separately, once before cutting to final length and once after. In accordance with some embodiments, the system uses a measurement encoder on the end effector of the robot that is routing individual wires on a wire harness form board to learn the length of each wire and its length variation. This information is then used to reduce wire scrap and reduce wire bundle assembly labor and flow time through automated double-ended wire pre-processing.
Although various embodiments of methods and apparatus for robot motion control and wire dispensing during automated routing of wires onto harness form boards systems are described in some detail later herein, one or more of those embodiments may be characterized by one or more of the following aspects.
One aspect of the subject matter disclosed in detail below is a wire-routing end effector comprising: a frame; a routing beak attached to and projecting from the frame, wherein the routing beak has a channel configured to guide a wire along a predetermined path relative to the frame as the wire moves through the channel; a drive roller comprising a drive roller shaft rotatably coupled to the frame, wherein the drive roller is arranged to contact a portion of the wire being guided in the channel of the routing beak; a motor having a motor output shaft; a roller drive train operatively coupled to the motor output shaft; a drive shaft operatively coupled to the roller drive train so that the drive shaft rotates when the motor output shaft rotates; a first right-angled drive shaft gear mounted to one end of the drive shaft; and a second right-angled drive shaft gear mounted to one end of the drive roller shaft and intermeshed with the first right-angled drive shaft gear, wherein the first and second right-angled drive shaft gears convert rotation of the drive shaft to rotation of the drive roller shaft.
In accordance with some embodiments of the wire-routing end effector described in the immediately preceding paragraph, the roller drive train comprises a first rubber drive roller affixed to the motor output shaft, a third rubber drive roller coupled to the drive shaft so that the drive shaft rotates when the third rubber drive roller rotates, and a second rubber drive roller configured to convert rotation of the first rubber drive roller to rotation of the third rubber drive roller. The wire-routing end effector further comprises a slotted drive bearing that transmits torque from the third rubber drive roller to the drive shaft while allowing the drive shaft to move up and down without binding.
Another aspect of the subject matter disclosed in detail below is an apparatus for routing a wire, comprising a manipulator arm, a wire-routing end effector coupled to the manipulator arm, and a robot controller configured to control movement of the manipulator arm and rotation of the wire-routing end effector relative to the manipulator arm, wherein the wire-routing end effector comprises: a first frame; and a routing beak attached to and projecting from the first frame, the routing beak having a height which decreases from a point of attachment to the first frame to a tip of the routing beak and having a channel configured to guide a wire along a predetermined path relative to the first frame as the wire moves through the channel, wherein the routing beak comprises an upper beak part having a first groove and a lower beak part having a second groove, wherein the first and second grooves form the channel, and wherein the upper beak part projects forward beyond the lower beak part. Optionally, the apparatus further comprises a force/torque sensor attached to and supporting the first frame and configured to output sensor data representing a force being exerted on the force/torque sensor by the first frame, wherein the robot controller is communicatively coupled to receive sensor data from the force/torque sensor and further configured to control movement of the manipulator arm taking into account the sensor data received from the force/torque sensor.
In accordance with some embodiments of the apparatus described in the immediately preceding paragraph, the wire-routing end effector further comprises: an encoder roller rotatably coupled to the first frame and configured to contact the wire being passed through the routing beak; and a rotary encoder coupled to the encoder roller and configured to convert each incremental rotation of the encoder roller into a signal representing encoder data indicating a direction of each incremental rotation of the encoder roller, wherein the robot controller is connected to receive the encoder data and configured to calculate a length of wire dispensed by the wire-routing end effector based on the encoder data received.
In accordance with one proposed implementation, the wire-routing end effector further comprises: a second frame that is rotatably coupled to the manipulator arm and to which the force/torque sensor is attached; a reelette rotatably coupled to the second frame and configured to contain at least a portion of the wire being guided by the routing beak; a drive roller comprising a drive roller shaft rotatably coupled to the first frame; a motor mounted to the second frame; a roller drive train rotatably coupled to the second frame and operatively coupled to the motor; a drive shaft operatively coupled to the motor by way of the roller drive train; a first right-angled drive shaft gear mounted to one end of the drive shaft; a second right-angled drive shaft gear mounted to one end of the drive roller shaft and intermeshed with the first right-angled drive shaft gear; an idle guide spring clamp arm rotatably coupled to the first frame; an idle guide roller comprising an idle guide roller shaft that is rotatably coupled to the idle guide spring clamp arm; and a spring that urges the idle guide spring clamp arm to rotate in a first rotation direction toward a position at which the idle guide roller forms a nip with the drive roller, wherein the idle guide roller displaces away from the drive roller when the idle guide spring clamp arm is rotated in a second rotation direction opposite to the first rotation direction.
A further aspect of the subject matter disclosed in detail below is a system comprising: a form board; a multiplicity of form board devices fastened to the form board; a manipulator arm; a wire-routing end effector coupled to the manipulator arm and comprising a first frame and a routing beak attached to and projecting from the first frame; and a robot controller configured to control movement of the manipulator arm and rotation of the wire-routing end effector relative to the manipulator arm such that a tool control point at the tip of the routing beak travels along a predefined routing path which has been calculated to avoid the routing beak colliding with any of the multiplicity of form board devices.
In accordance with some embodiments of the system described in the immediately preceding paragraph, at least one of the multiplicity of form board devices is a wire routing device comprising: a second frame comprising upper and lower arms, the lower arm having a hole; a routing clip fastened to the upper arm of the second frame, the routing clip comprising first and second flexible clip arms configured to bend resiliently away from each other, and first and second hooks respectively connected to or integrally formed with the first and second flexible clip arms; and a temporary fastener fastened to the hole in the lower arm and to a hole in the form board, wherein the robot controller is further configured to control movement of the manipulator arm such that the routing beak approaches the routing clip in a first plane, locally dips to a second plane, passes between the first and second flexible clip arms in the second plane, and then locally rises to the first plane.
In accordance with other embodiments, at least one of the multiplicity of form board devices is a first-end wire connector support device comprising: a second frame comprising a lower arm having a hole and a notched projection having a notch; and a temporary fastener fastened to the hole in the lower arm and to a hole in the form board, wherein the robot controller is further configured to control movement of the manipulator arm such that the routing beak places the wire in the notch with a contact attached to an end of the wire hooked behind the notched projection.
A further aspect of the subject matter disclosed in detail below is a wire-routing end effector comprising: a first frame; a force/torque sensor attached to and supporting the first frame and configured to output sensor data representing a force being exerted on the force/torque sensor by the first frame; and a routing beak attached to and projecting from the first frame, the routing beak having a height which decreases from a point of attachment to the first frame to a tip of the routing beak and having a channel configured to guide a wire along a predetermined path relative to the first frame as the wire moves through the channel.
In accordance with one proposed implementation, the wire-routing end effector described in the immediately preceding paragraph further comprises: a second frame that is rotatably coupled to the manipulator arm and to which the force/torque sensor is attached; a reelette rotatably coupled to the second frame and configured to contain at least a portion of the wire being guided by the routing beak; a drive roller comprising a drive roller shaft rotatably coupled to the first frame; a motor mounted to the second frame; a roller drive train rotatably coupled to the second frame and operatively coupled to the motor; a drive shaft operatively coupled to the motor by way of the roller drive train; a first right-angled drive shaft gear mounted to one end of the drive shaft; a second right-angled drive shaft gear mounted to one end of the drive roller shaft and intermeshed with the first right-angled drive shaft gear; a rotary encoder configured to output a signal representing encoder data indicating a direction of each incremental rotation of the drive roller; an idle guide spring clamp arm rotatably coupled to the first frame; an idle guide roller comprising an idle guide roller shaft that is rotatably coupled to the idle guide spring clamp arm; and a spring that urges the idle guide spring clamp arm to rotate in a first rotation direction toward a position at which the idle guide roller forms a nip with the drive roller, wherein the idle guide roller displaces away from the drive roller when the idle guide spring clamp arm is rotated in a second rotation direction opposite to the first rotation direction.
Another aspect of the subject matter disclosed in detail below is a method for retaining a bundle of wires on a form board, the method comprising: (a) moving a wire-routing end effector mounted to a manipulator arm so that a routing beak of the wire-routing end effector contacts a clip while a first portion of a first wire extends outside a channel of the routing beak from a tip of the routing beak and a second portion of the first wire is disposed in the channel, the clip having first and second flexible clip arms which are urged by respective spring forces toward one another; (b) continuing to move the wire-routing end effector so that the routing beak exerts respective separating forces greater than the respective spring forces to cause the first and second flexible clip arms to move to open the clip; (c) continuing to move the wire-routing end effector so that the tip of the routing beak passes between and the second portion of the first wire is disposed between the first and second flexible clip arms of the open clip; (d) continuing to move the wire-routing end effector until the routing beak no longer contacts the first and second flexible clip arms, thereby allowing the spring forces to move the first and second flexible clip arms to close the clip, as a result of which the second portion of the first wire is retained by the closed clip; (e) moving the wire-routing end effector so that the routing beak contacts the clip while a first portion of a second wire extends outside a channel of the routing beak from a tip of the routing beak and a second portion of the second wire is disposed in the channel; (f) continuing to move the wire-routing end effector so that the routing beak exerts respective separating forces greater than the respective spring forces to cause the first and second flexible clip arms to move to open the clip; (g) continuing to move the wire-routing end effector so that the tip of the routing beak passes between and the second portion of the second wire is disposed between the first and second flexible clip arms of the open clip; (h) continuing to move the wire-routing end effector until the routing beak no longer contacts the first and second flexible clip arms, thereby allowing the spring forces to move the first and second flexible clip arms to close the clip, as a result of which the second portion of the second wire is retained by the closed clip, wherein during step (c) a tool center point of the wire-routing end effector follows a first path and during step (g) the tool center point of the wire-routing end effector follows a second path which is offset from the first path.
Yet another aspect of the subject matter disclosed in detail below is a method for routing a wire on a form board configured with form board devices, the method comprising: (a) placing a portion of a wire in a channel of a routing beak of a wire-routing end effector mounted to a manipulator arm such that a contact attached to an end of the wire is positioned forward of a tip of the routing beak; (b) moving the wire-routing end effector and the end of the wire until the tip of the routing beak is at a contact start point overlying a notch of a first-end connector support device which is attached to the form board; (c) further moving the wire-routing end effector and the end of the wire until the tip of the routing beak is at a contact parking point at which the contact on the end of the wire is hooked behind the notch; (d) further moving the wire-routing end effector away from the first-end connector support device until the tip of the routing beak is at a connector reference point beyond a separation plane while the contact remains hooked on the notch; (e) pushing wire out of the routing beak as the wire-routing end effector moves during step (d); (f) gripping the wire at a point near the end of the wire using a gripper of an contact-insertion end effector while the routing beak is beyond the separation plane; (g) moving the contact-insertion end effector and the end of the wire so that the contact is moved away from the notch and inserted into a hole of a first-end connector supported by the first-end connector support device; (h) upon completion of step (g), further moving the wire-routing end effector toward the first-end connector support device until the tip of the routing beak is at a start routing point while the contact remains inserted into the hole of the first-end connector; (i) pulling wire into the routing beak as the wire-routing end effector moves during step (h); (j) further moving the wire-routing end effector so that the tip of the routing beak follows a predefined routing path through at least one form board device; (k) pushing wire out of the routing beak as the wire-routing end effector moves during step (j); and (l) further moving the wire-routing end effector until the tip of the routing beak is at an end point situated on a far side of a wire holding device which is attached to the form board such that a portion of the wire is held by the wire holding device.
Other aspects of methods and apparatus for robot motion control and wire dispensing during automated routing of wires onto harness form boards are disclosed below.
The features, functions and advantages discussed in the preceding section may be achieved independently in various embodiments or may be combined in yet other embodiments. Various embodiments will be hereinafter described with reference to drawings for the purpose of illustrating the above-described and other aspects. None of the diagrams briefly described in this section are drawn to scale.
Reference will hereinafter be made to the drawings in which similar elements in different drawings bear the same reference numerals.
For the purpose of illustration, methods and apparatus for robot motion control and wire dispensing during automated routing of wires onto harness form boards will now be described in detail. However, not all features of an actual implementation are described in this specification. A person skilled in the art will appreciate that in the development of any such embodiment, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
In the aerospace industry, wires are typically assembled into wire bundles on a harness form board. Some harnesses may have hundreds or thousands of wires. While the length of the centerline of each wire bundle branch is precisely designed, the length of each wire is not typically known because the individual wires are not typically laid down in a repeatable sequence and/or position within the branch and because the harness is not typically tied in a repeatable sequence. Thus, each individual wire is typically cut extra-long and the wires are trimmed to their final lengths after many of the wires have been placed on the form board and tied together. Trimmed and discarded wire adds extra material cost.
The wire bundle assembly process proposed herein includes the following steps: (1) Individual wires are marked and cut with extra length. (2) The first end of each wire is prepared (strip off insulation, crimp contact). (3) “First-end” connectors are placed on a form board. (4) Robotically place and route each wire onto the form board in a repeatable sequence, including (a) inserting the first end of the wire into a first-end connector; (b) routing the wire to its second-end destination on the form board; and (c) temporarily securing the second end of the wire to the form board by attaching it to a clip or retaining device. (5) When all of the wires of a bundle have been routed, the wires are tied together in a repeatable sequence to secure the form of the wire bundle. (6) The wires are then cut to final length at known locations, which may be printed on the form board. (7) The wire bundle assembly is then removed from the form board. (8) The second ends of the wires are then prepared (strip off insulation, crimp contact). (9) The second ends of the wires of each branch are then inserted into respective second-end connectors.
As the wires are being robotically routed on the form board to their second-end destinations, the wire length is measured by a sensor associated with the robot. The sensor may be an encoder wheel that the wire passes over while being dispensed during routing. The measurement starts after the contact on the first end of the wire has been inserted into the first-end connector and continues until the robot reaches the known location for the wire's second-end cut. An extra amount may be added to the length to account for the length of wire dispensed during the contact insertion function, which insertion operation may be performed robotically using a contact-insertion end effector.
During a routing operation, the tool control point of the wire-routing end effector travels along one predefined path, but the wire itself will likely come to rest along a different path within the bundle. Wires will position themselves within form board wire supports and will roll off of each other in somewhat random ways. Thus, the robot path length and the measured wire length will likely be different. This is why it is important to measure the actual amount of wire dispensed during routing from the first-end connector to the known second-end cut location. The measured lengths are recorded in a database for each wire in the harness.
The above-described process may be repeated over multiple builds of the harness. A statistical analysis may be computed to determine whether the wire lengths are statistically controlled within a specified tolerance. When the wire lengths are statistically controlled within a specified tolerance, several advantages may be realized: The amount of extra length used when cutting wires may be reduced, thus reducing scrap wire and associated material costs.
In accordance with an alternative embodiment, as the wires are being marked and cut, a marking including symbols representing the wire's identity is included as close as possible to the second end of the wire (or to both ends). The marking may be alphanumeric or barcode.
After the wires have been cut to their final length at their respective second ends, the cut ends of the wires are run through an optical scanning system. The optical scanning system identifies each wire from the markings on the respective cut ends and measures the wire's cutoff length. If the system is unable to read the wire identity or measure the wire cutoff length, the cut wire end may be passed through the optical scanning system for repeated attempts. The measured cutoff lengths are subtracted from the initial wire cut length to calculate the final routed length of the wire, which is recorded in a database for each wire in the harness.
The above-described process may be repeated over multiple builds of the harness. A statistical analysis may be computed to determine whether the wire lengths are statistically controlled within a specified tolerance. When the wire lengths are statistically controlled within a specified tolerance, several advantages may be realized: The amount of extra length used when cutting wires may be reduced, thus reducing scrap wire and associated material costs.
In addition, the second ends of the wires may be processed in the same stage during which the first ends are processed, thereby eliminating the preparation of second ends after the harness has been removed from the form board. This transfers work usually done manually after removal of the harness to a stage when the process of preparing ends of the wires may be an automated task, thereby reducing manual labor costs and factory flow time. In addition, automated insertion of the second ends of the wires may be enabled by accurately positioning the prepared second ends of the wires for insertion into the second-end connector.
The automated wire routing process disclosed herein may be performed by a robotic system that includes multiple articulated robots. Each articulated robot may be implemented using, for example, without limitation, a jointed manipulator arm. Depending on the implementation, each articulated robot may be configured to provide movement and positioning of at least one tool center point corresponding to that robot with multiple degrees of freedom. As one illustrative example, each articulated robot may take the form of a manipulator arm capable of providing movement with up to six degrees of freedom or more.
In one illustrative example, the articulated robots of the robotic system may take a number of different forms, such as a wire-routing robot and a wire-insertion robot. Each articulated robot has a tool coordinate system. The tool coordinate system consists of two components: a tool frame of reference and a tool center point (TCP). The tool frame of reference includes three mutually perpendicular coordinate axes; the TCP is the origin of that frame of reference. When the robot is instructed to move at a certain speed, it is the speed of the TCP that is controlled. The tool coordinate system is programmable and can be “taught” to the robot controller for the particular end effector attached to the manipulator arm. In the case of the wire-routing end effector, each path of the TCP may be offset from the previous path during the assembly of a particular wire bundle. One way to achieve this is to program the robot controller with a respective set of motion instructions for each wire path. In the alternative, one motion instruction may be executed in a repetitive loop with incremental offsets being introduced after each pass.
For example, in accordance with one proposed implementation, a method for retaining a bundle of wires on a form board comprises the following steps: (a) moving a wire-routing end effector mounted to a manipulator arm so that a routing beak of the wire-routing end effector contacts a clip while a first portion of a first wire extends outside a channel of the routing beak from a tip of the routing beak and a second portion of the first wire is disposed in the channel, the clip having first and second flexible clip arms which are urged by respective spring forces toward one another; (b) continuing to move the wire-routing end effector so that the routing beak exerts respective separating forces greater than the respective spring forces to cause the first and second flexible clip arms to move to open the clip; (c) continuing to move the wire-routing end effector so that the tip of the routing beak passes between and the second portion of the first wire is disposed between the first and second flexible clip arms of the open clip; (d) continuing to move the wire-routing end effector until the routing beak no longer contacts the first and second flexible clip arms, thereby allowing the spring forces to move the first and second flexible clip arms to close the clip, as a result of which the second portion of the first wire is retained by the closed clip; (e) moving the wire-routing end effector so that the routing beak contacts the clip while a first portion of a second wire extends outside a channel of the routing beak from a tip of the routing beak and a second portion of the second wire is disposed in the channel; (f) continuing to move the wire-routing end effector so that the routing beak exerts respective separating forces greater than the respective spring forces to cause the first and second flexible clip arms to move to open the clip; (g) continuing to move the wire-routing end effector so that the tip of the routing beak passes between and the second portion of the second wire is disposed between the first and second flexible clip arms of the open clip; (d) continuing to move the wire-routing end effector until the routing beak no longer contacts the first and second flexible clip arms, thereby allowing the spring forces to move the first and second flexible clip arms to close the clip, as a result of which the second portion of the second wire is retained by the closed clip. During step (c), a tool center point of the wire-routing end effector follows a first path; during step (g), the tool center point of the wire-routing end effector follows a second path which is offset from the first path.
As used herein, the term “wire routing device” means a hardware tool that is configured so that, when the wire routing device is fastened to a form board, a portion of the wire routing device will limit movement of a contacting section of a wire in at least one lateral direction which is parallel to the X-Y plane of the form board to which the wire routing device is attached. As used herein, the term “C-frame” means a relatively stiff channel-shaped bracket having mutually parallel upper and lower arms and does not mean a frame having a C-shaped profile. In accordance with the embodiments disclosed herein, the C-frame further includes a member that connects the upper arm to the lower arm.
In accordance with one proposed implementation, the form board 2 is made from a rectangular ⅛-inch-thick perforated sheet with ⅛-inch-diameter holes spaced approximately 3/16 inch (4.7625 mm) apart in a hexagonal pattern. Thus, the vertical spacing between rows is approximately 3/16 (inch)×sin 60°=0.1623798 inch or 4.124446 mm. The sheet is made of aluminum and optionally is coated with a high-friction material. The perforated sheet may be bonded to the top face of a honeycomb core while a second sheet is bonded to the bottom face of the honeycomb core to form a stiff panel.
The form board 2 is typically mounted to or forms part of a support frame (not shown in
The first-end connector 20 also includes a contact-receiving insert 28 having a multiplicity of spaced holes 24. The contact-receiving insert 28 is typically made of dielectric material. For a particular wire bundle configuration, the respective contacts of wires to be terminated at first-end connector 20 are inserted into respective holes 24 in contact-receiving insert 28 by a contact-insertion end effector 18 (seen in
Referring again to
The temporary fastener 34 includes a cylindrical housing 38 with an annular flange 35 extending around the housing 38. A plunger 40 is slidably coupled to the housing 38. A portion of the plunger 40 projects from one end of the housing 38. A spacer (not visible in
Still referring to
The wire routing device 12 depicted in
In accordance with some embodiments, after the contact at the end of a wire has been inserted into the first-end connector 20 depicted in
The wire-routing end effector 14 depicted in
In the embodiment depicted in
The wire-routing end effector 14 further includes a pair of wire-displacing rollers (e.g., a drive roller and an idle guide roller) designed to push and pull a wire through the routing beak 16 which dispenses the wire. In accordance with one proposed implementation, the pair of wire-displacing rollers each have outer peripheral contact surfaces made of compliant material which contact each other to form a nip. The drive roller (not visible in
Some of the components of the drive train that operatively couple the drive roller shaft 92 to the stepper motor 74 are visible in
The drive train that operatively couples the drive roller shaft 92 to stepper motor 74 further includes a first right-angled drive shaft gear 86 mounted to one end of the vertical drive shaft 84 and a second right-angled drive shaft gear 94 mounted to one end of the drive roller shaft 92. At all times at least some teeth of the first right-angled drive shaft gear 86 are intermeshed with some teeth of the second right-angled drive shaft gear 94, thereby converting rotation of the vertical drive shaft 84 into rotation of the drive roller shaft 92.
The vertical drive shaft 84 is operatively coupled to both the upper frame 56 and the lower frame 58. To accommodate the fact that the lower frame 58 is movable relative to the upper frame, the wire-routing end effector 14 further includes a slotted drive bearing that transmits torque from the third rubber drive roller 72c to the vertical drive shaft 84 while allowing the vertical drive shaft 84 to move up and down slightly (along the axis of the vertical drive shaft 84) without binding. One reason for doing this is to isolate the large, unpredictable masses of the reelette from the lower frame 56 so that the force/torque sensor 76 would be exposed to less noise.
As best seen in
Referring again to
As best seen in
The idle guide spring clamp arm 98 is an adjustable spring lever-arm to set and maintain appropriate force for idle guide roller-to-drive roller interference. Its primary function is to prevent slipping between the drive roller 73 and wire(s) of various gauges, cross sections, and jacket surface frictions. In accordance with the embodiment of the powered wire-routing end effector 14 depicted in
The drive roller 73 and idle guide roller 75 each have outer peripheral contact surfaces made of compliant material (e.g., rubber). When the compression spring 100 pushes the idle guide roller 75 into contact with the drive roller 73, the compliant surfaces form a nip with sufficient friction that the idle guide roller 75 will rotate as the drive roller 73 rotates. The drive roller shaft 92 is capable of bidirectional rotation. When a wire is present in the nip, the portion of the wire in the nip is pushed toward the routing beak 16 during rotation of the drive roller shaft 92 in a first direction. Alternatively, the portion of the wire in the nip is pulled away from the routing beak 16 during rotation of the drive roller shaft 92 in a second direction opposite to the first direction.
Optionally, the wire-routing end effector 14 may be provided with a rotary encoder not shown in
The stored encoder data may be used to calculate the length of wire which has been dispensed during any interval of time. For example, the encoder data may be used to calculate the total length of wire that was dispensed as the TCP of the robotic system traveled along a routing path from a routing start point to a routing end point. This measurement may also be used to calculate the actual length of a wire that extends from the first-end connector to a known second-end cut location. The measured lengths are recorded in a database for each wire in a harness. The amount of waste produced during assembly of future wire bundles may be better optimized when the individual wire lengths are logged, evaluated, and corrected over time. For example, successive wires routed along the same routing path may increase in length overall as each wire conforms to the accumulated total bundle previously routed.
The wire-routing end effector 14 may be coupled to the distal end of a manipulator arm of a robot. The robot may include either a mobile pedestal or a gantry which carries the manipulator arm. The robot further includes a robot controller configured to control movement of the mobile pedestal or gantry relative to ground, movement of the manipulator arm relative to the mobile pedestal or gantry, and rotation of the wire-routing end effector relative to the manipulator arm. The robot controller is communicatively coupled to receive sensor data from the force/torque sensor 76. The robot controller is further configured to control movement of the manipulator arm, taking into account the sensor data received from the force/torque sensor 76. This enables the robot controller to control tension during routing. The sensor data may also be used to detect wire snags or end effector collisions during routing.
During movement of the TCP from the Contact Parking Point to the Connector Reference Point, the contact 3 remains inside the first-end connector and the wire terminated by that contact does not move in a lengthwise direction (the wire may move laterally or vertically if the routing beak 16 so moves). As the routing beak 16 travels along the wire in a direction away from the first-end connector 20, the drive roller 73 is driven to rotate in a direction that causes a length of wire to be dispensed from the wire-routing end effector 14. The frictional forces exerted on the wire by the routing beak 16 and the rollers (drive roller 73 and idle guide roller 75) produce tension in the wire. Meanwhile the force/torque sensor 76 of the wire-routing end effector 14 senses the tension in the wire and sends sensor data representing those measurements to a robot controller. The robot controller is configured (e.g., programmed) to control both movement of the wire-routing end effector 14 and the rotational speed of the drive roller 73 so that tension in the segment of wire extending from the first-end connector 20 to the drive roller 73 does not exceed a specified upper limit.
When the wire-routing end effector 14 (mounted to a first manipulator arm) is safely beyond the separation plane 30, a contact-insertion end effector 18 (mounted to a second manipulator arm) is moved so that a pair of grippers grip the wire near the contact. Then the grippers lift the gripped portion of the wire up until the contact is clear of the notch 25. Thereafter the contact-insertion end effector 18 moves to the position depicted in
After the contact has been inserted into the first-end connector 20, the contact-insertion end effector 18 is moved to a location where the contact-insertion end effector 18 will not obstruct the wire-routing end effector 14.
During movement of the TCP from the Connector Reference Point to the Start Routing Point, the contact 3 remains inside the first-end connector and the wire terminated by that contact does not move in a lengthwise direction. As the routing beak 16 travels along the wire in a direction toward the first-end connector 20, the drive roller 73 is driven to rotate in a direction that causes a length of wire to be reeled back into the wire-routing end effector 14.
When the TCP reaches the Start Routing Point, the robot controller initiates execution of a program that controls a sequence of movements of the wire-routing end effector 14, which movements include rotations and translations. The movements are controlled in accordance with a predefined program that specifies a TCP path designed to route the wire through or around selected form board devices 4 attached to the form board 2. One example sequence of movements is depicted in
After the TCP is positioned at the End Point, the receiving beak 16 is moved such that the TCP follows the TCP path segment indicated by bold line 7f in
In accordance with one embodiment, wire routing occurs in a routing cell. First, the operator inserts a form board into the routing cell and informs the robot system of the configuration of the form board by scanning a barcode on the form board. Then the operator loads a rack of reelettes into the routing cell. Then the robot system routes wires on the form board, one wire at a time. The robot system determines which wire reelettes are available for it to pick (by reading barcodes on the reelettes) and compares the available wires to the wires listed in a wire data control file. The robot system is configured to load the reelette closest to the top of the sequence given by the wire data control file onto the wire-routing end effector. Then the robot system identifies the routing path from the wire data control file and routes the wire following this path using the wire-routing end effector. The robot system also uses a contact-insertion end effector to pick the first end of the wire and either insert it into the first-end connector or place it in an adjacent wire end holder, as specified in the wire data control file. Upon completion of the wire routing operation, the robot system applies plastic wire ties using a wire tie control file. Then the robot system cuts second-end branches using a branch cut control file.
Software algorithms ensure that the wire-routing end effector 14 does not have any hard collisions with the form board devices 4 or any previously routed wires during the routing process. A “hard collision” is one that causes damage to wires, connectors, form board devices, form board, end effectors, or robots.
As previously described, some of the form board devices 4 depicted in
In alternative embodiments, a wire-routing end effector that is not powered may be used to route a wire on a form board.
Referring to
The passive wire-routing end effector 54A further includes a passive tensioner arm 104 (shown in
As seen in
As the passive wire-routing end effector 54A moves in the volume of space above the form board 2, the vertical axis indicated in
The robot system may be in the form of a pedestal robot or a gantry robot. A gantry robot consists of a manipulator mounted onto an overhead system that allows movement across a horizontal plane. Gantry robots are also called Cartesian or linear robots. The pedestal robot may have multi-axis movement capabilities. An example of a robot that could be employed with the wire-routing end effector is robot Model KR-150 manufactured by Kuka Roboter GmbH (Augsburg, Germany), although any robot or other manipulator capable of controlling the location of the routing beak 16 in the manner disclosed herein may be used.
While methods and apparatus for robot motion control and wire dispensing during automated routing of wires onto harness form boards have been described with reference to various embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the teachings herein. In addition, many modifications may be made to adapt the teachings herein to a particular situation without departing from the scope thereof. Therefore it is intended that the claims not be limited to the particular embodiments disclosed herein.
As used herein, the term “computer system” should be construed broadly to encompass a system having at least one computer or processor, and which may have multiple computers or processors that communicate through a network or bus. As used in the preceding sentence, the terms “computer” and “processor” both refer to devices comprising a processing unit (e.g., a central processing unit) and some form of memory (i.e., a non-transitory tangible computer-readable storage medium) for storing a program which is readable by the processing unit.
The methods described herein may be encoded as executable instructions embodied in a non-transitory tangible computer-readable storage medium, including, without limitation, a storage device and/or a memory device. Such instructions, when executed by a computer system, cause the wire routing end effector to perform at least a portion of the methods described herein.
The process claims set forth hereinafter should not be construed to require that the steps recited therein be performed in alphabetical order (any alphabetical ordering in the claims is used solely for the purpose of referencing previously recited steps) or in the order in which they are recited unless the claim language explicitly specifies or states conditions indicating a particular order in which some or all of those steps are performed. Nor should the process claims be construed to exclude any portions of two or more steps being performed concurrently or alternatingly unless the claim language explicitly states a condition that precludes such an interpretation.
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