System for autonomous attachment of metal decking
An autonomous system attaches corrugated metal decking to roof structural members such as purlins, trusses or joists using a motorized wheeled carriage that traverses deck corrugations and drives threaded fasteners with closed-loop control. A fastener management module holds structural and sidelap screws in separate hoppers, orients them via screw sorters, and distributes them by a linearly translatable gantry to multiple drill units. Each unit includes a PWM-controlled drill, a linear actuator for plunge, and a spring-biased jaw release cooperating with a magnetized nut driver. A sensor assembly within a corrugation detects structural members, guides lateral alignment, and senses pre-existing fasteners; metal deck edge range sensors and a fail-safe brake preventing the system from running off the roof deck. Controllers networked over CAN coordinate motion, torque, patterns, speed, plunge of the fastening system, verify seating by motor/force feedback, and generate audit records of as-installed locations.
1 . A system for autonomously attaching corrugated metal decking to structural members, comprising:
a motorized wheeled carriage configured to traverse the decking;
a fastener management subsystem including first and second hoppers for structural and sidelap fasteners, respective screw sorters that orient fasteners head-up, and a distribution assembly having a linearly translatable gantry with a sled configured to selectively route oriented fasteners through flexible conduits to any one of a plurality of fastening units;
the plurality of fastening units each comprising an electric drill, a pulse-width-modulated speed controller coupled to the drill, a linear actuator coupled to translate the drill toward the decking, a nut driver received in a chuck of the drill, and a spring-biased jaw release positioned to retain a fastener by its head until engagement by the nut driver during a plunge stroke;
a sensor assembly arranged to enter a corrugation of the decking and including (i) roof structure detectors responsive to proximity of a roof structural member, (ii) corrugation guide sensors each having at least one guide wheel on a biased shaft with a rotary encoder to indicate lateral deviation, and (iii) detectors for existing fasteners each comprising a spring-loaded mechanical swing linked to a photo-interrupter;
metal deck sheet-edge range sensors mounted to the carriage; and
one or more electronic controllers operatively coupled to wheel motor drivers, the fastener management subsystem and the fastening units via a communication bus, the controllers being configured to: (A) navigate the carriage along a selected corrugation using feedback from the corrugation guide sensors; (B) stop the carriage in response to the structural member detectors; and (C) actuate selected fastening units according to a stored pattern to drive fasteners with controlled torque into the decking and the structural members.
2 . The system of claim 1 , wherein the fastener management subsystem further comprises optical presence sensors located at (i) exits of the screw sorters, (ii) the gantry sled, and (iii) an inlet of each spring-biased jaw release, each optical presence sensor being a fork-type interrupter configured to detect a passing fastener and to signal a jam condition.
3 . The system of claim 1 , further comprising a fail-safe braking assembly including opposed brake arms biased together by a spring to frictionally engage a hub of a wheel of the carriage upon loss of electrical power, and an electrically driven cam configured to separate the brake arms during powered operation.
4 . The system of claim 1 , wherein the controllers are further configured to determine proper seating and thread engagement by monitoring at least one of drill motor current and linear-actuator force to detect a threshold indicative of seating, and to retract the linear actuator when the threshold is exceeded.
5 . The system of claim 1 , wherein the controllers inhibit any plunge or rotation unless optical presence sensors confirm fastener presence at (i) exits of the screw sorters, (ii) the gantry sled, and (iii) an inlet of each spring-biased jaw release.
6 . The system of claim 1 , wherein each detector for existing fasteners comprises a spring-loaded mechanical swing linked to a photo-interrupter and the controllers inhibit actuation when the swing deflects and interrupts the photo-interrupter beam.
7 . The system of claim 1 , wherein the metal deck sheet-edge sensors comprise a laser rangefinder configured to detect elevation change within a range of about 150 mm to 2 m and to operate on 10-30 VDC.
8 . The system of claim 1 , wherein upon loss of electrical power the tension spring rotates the cam to permit the brake arms to engage the hub and stop wheel rotation.
9 . The system of claim 1 , wherein the controllers determine proper seating by monitoring drill-motor current and/or linear-actuator force against a threshold profile and retract the actuator when the threshold is exceeded.
10 . The system of claim 1 , wherein the controllers log for each drive cycle at least location, torque/current or force signature, and pass/fail of seating for later analysis.
11 . The system of claim 1 , wherein the controllers communicate with wheel motor drivers, linear actuators, screw sorters, and sensors over a controller-area network using CANopen.
12 . The system of claim 1 , further comprising wheel hub encoders providing at least 4096 counts per revolution used by the controllers to determine sidelap screw spacing between structural-member events.
13 . The system of claim 1 , wherein the controller determines a structural-member location by computing phase shift between voltage and current zero-crossings of an excitation waveform applied to the primary winding.
14 . The system of claim 1 , wherein the controllers command the gantry to align a distribution outlet with a selected fastening unit, confirm fastener presence with an optical interrupter at the unit inlet, and only then authorize a plunge sequence that mechanically opens the spring-biased jaw release by engagement of the nut driver.
15 . A non-transitory computer-readable medium storing instructions that, when executed by one or more controllers of an autonomous metal deck fastening system, cause the controllers to:
perform a pre-operation self-test and accept session settings including a fastening pattern, travel direction and sidelap fastener spacing;
home a fastener distribution gantry and enable screw sorters to stage oriented fasteners;
lower a sensor assembly into a corrugation of a corrugated metal decking while maintaining a carriage heading from corrugation guide sensor feedback;
navigate along the corrugation, stop over a detected purlin top chord, and actuate selected fastening units so that a linear actuator plunges a drill while a pulse-width-modulated signal sets drill speed to drive a fastener released from a spring-biased jaw mechanism;
advance between structural-fastener locations and sidelap-fastener intervals according to the stored pattern; and
enforce interlocks that inhibit motion or actuation upon detection of a metal deck edge or an obstacle.
16 . The non-transitory computer-readable medium of claim 15 , wherein the instructions further cause the controllers to communicate with wheel motor drivers, linear actuators, screw sorters, and sensors over a controller area network using a CANopen protocol.
17 . The non-transitory computer-readable medium of claim 15 , wherein the instructions further cause the controllers to determine a fastener-seating event by comparing drill motor current and/or linear-actuator force to a threshold profile and to retract the linear actuator when the seating event is detected.
18 . The non-transitory computer-readable medium of claim 15 , wherein the instructions further cause the controllers to command the gantry to align a distribution outlet with a selected fastening unit, confirm fastener presence with an optical interrupter at the fastening unit inlet, and only then authorize a plunge sequence that mechanically opens the spring-biased jaw release by engagement of the nut driver.
19 . The non-transitory computer-readable medium of claim 15 , wherein the instructions cause the controllers to communicate with wheel motor drivers, linear actuators, screw sorters, and sensors over a controller-area network using CANopen.
20 . The non-transitory computer-readable medium of claim 15 , wherein the instructions cause the controllers to determine a seating event by comparing drill-motor current and/or linear-actuator force to a threshold profile and to retract the actuator when the seating event is detected.
21 . The non-transitory computer-readable medium of claim 15 , wherein the instructions cause the controllers to command gantry alignment, confirm fastener presence with an optical interrupter at the fastening-unit inlet, and only then authorize a plunge sequence that mechanically opens the spring-biased jaw release by engagement of the nut driver.
22 . A system for autonomously attaching corrugated metal decking to structural members and fastening sidelaps, comprising:
a motorized wheeled carriage configured to traverse the decking;
a fastener management subsystem including a first hopper for structural pins and a second hopper for sidelap screws, that present pins point-down, screw sorters that present screws head-up, and a distribution assembly having a linearly translatable gantry with a sled configured to selectively deliver pins or screws to selected fastening units;
a plurality of structural fastening units, each comprising a pin-driving head powered by one of (i) a pneumatic circuit including a regulated pressure source and a firing valve or (ii) a powder-actuated mechanism, a linear actuator coupled to translate the pin-driving head toward the decking, and a magazine or feed throat receiving pins from the distribution assembly;
a plurality of sidelap fastening units, each comprising an electric drill, a pulse-width-modulated speed controller coupled to the drill, a linear actuator coupled to translate the drill toward the decking, a nut driver received in a chuck of the drill, and a spring-biased jaw release positioned to retain a screw by its head until engagement by the nut driver during a plunge stroke;
a sensor assembly arranged to enter a corrugation of the decking and including (i) roof structure detectors responsive to proximity of a roof structural member, (ii) corrugation guide sensors each having at least one guide wheel on a biased shaft with a rotary encoder to indicate lateral deviation, and (iii) detectors for existing fasteners each comprising a spring-loaded mechanical swing linked to a photo-interrupter;
one or more electronic controllers operatively coupled to wheel motor drivers, the fastener management subsystem, and the fastening units via a communication bus, the controllers being configured to: (A) navigate the carriage along a selected corrugation using feedback from the corrugation guide sensors; (B) stop the carriage in response to the structural member detectors; and (C) actuate fastening units according to a stored pattern such that, at structural-member locations, a selected structural fastening unit is plunged, and a pneumatic discharge or powder-actuated shot commanded to drive a metal pin through the decking into the structural member, while at sidelap locations, a selected sidelap fastening unit is plunged and a drill rotates the nut driver to drive a screw through overlapping sheets-whereby only the fasteners driven into structural members are installed by pneumatic or powder-actuated discharge and sidelap fasteners are installed by a drill.
23 . A non-transitory computer-readable medium storing instructions that, when executed by one or more controllers of an autonomous metal deck fastening system, cause the controllers to:
perform a pre-operation self-test and accept session settings including a fastening pattern, travel direction, sidelap screw spacing, and an energy profile mapping structural-pin type to pneumatic pressure or powder charge level;
home a fastener distribution gantry and enable pin orienters or strip feeders to stage pins and screw sorters to stage screws;
lower a sensor assembly into a corrugation of a corrugated metal decking while maintaining a carriage heading from corrugation guide sensor feedback;
navigate along the corrugation, stop over a detected purlin top chord, and for structural-member locations actuate a structural fastening unit so that a linear actuator plunges a pin-driving head, and commands a pneumatic discharge or powder-actuated shot to drive a metal pin;
advance between structural-pin locations and at sidelap intervals actuate a sidelap fastening unit so that a linear actuator plunges a drill while a pulse-width-modulated signal sets drill speed to drive a screw released from a spring-biased jaw mechanism through overlapping sheets; and
enforce interlocks that inhibit motion or actuation upon detection of a metal deck edge, an obstacle, a missing-fastener condition, or a contact-trip not engaged, whereby pneumatic or powder-actuated discharge is used only for fasteners driven into structural members while sidelap fasteners are installed by a drill.