WO2020204966A1

WO2020204966A1 - Method and system for 3d printing a concrete structure

Info

Publication number: WO2020204966A1
Application number: PCT/US2019/031947
Authority: WO
Inventors: Larry HAINES
Original assignee: Sunconomy, Llc
Priority date: 2019-03-31
Filing date: 2019-05-13
Publication date: 2020-10-08

Abstract

A method and system for printing a concrete structure uses a 3D printhead disposed on a mobile platform capable of autonomously printing an entire structure on a build site. The method uses reinforced insulated panels as structural members that provide improved insulation and structural support. The reinforced insulated panels are sprayed with structural concrete such as geopolymer concrete. The 3D printhead includes at least three degrees of freedom, including the rotation of the nozzle, allowing the system to print patterns in locations where other nozzle systems cannot. The mobile autonomous printing system may spray concrete on the panels in accordance with an inputted model of the structure to be constructed on the build site. Instead of relying on a structure consisting entirely of concrete, the resulting structure includes insulation, wire frame structural support, and structural concrete covered the panels that improves insulation, strength, and long-term reliability of the structure.

Description

METHOD AND SYSTEM FOR 3D PRINTING A CONCRETE STRUCTURE

BACKGROUND OF THE INVENTION

[0001] The affordable housing crisis has reached epidemic proportions and threatens to destabilize economies around the world. Notwithstanding those priced out of the housing market entirely, a significant number of households are severely burdened by housing costs that exceed fifty percent of the family’s income and rental rates continue to outpace inflation in many markets. While unsustainable housing costs and rising rental rates have a disparate impact on the homeless and low-income families, the affordable housing problem also affects moderate-income families as well as the growing population of aging seniors. Senior citizens are spending a disproportionate amount of their fixed income on housing, often foregoing essentials including food and medical care. Experts have argued that the primary driver of the crisis is the shortage of affordable housing options. However, demand continues to outpace supply, driving housing costs higher. While the affordable housing crisis is pervasive in economically advantaged western countries, the problem is worse still in developing countries where there is an acute shortage of minimally sufficient housing for millions of people and few resources to address the shortage.

[0002] Another contributor to the housing crisis, albeit to a lesser extent, relates to the damage or destruction of housing caused by natural and other disasters. Each year, hundreds of thousands of homes are damaged or destroyed in hurricanes, floods, earthquakes, droughts, and wildfires. The displacement of previously housed families stresses the housing market and typically results in increased rental rates and lesser availability of housing generally. In many instances, the displaced must rely on temporary housing, such as trailers, provided by the Federal Emergency Management Agency, for shelter. After a natural disaster, it is not unusual for displaced families to live in temporary housing for months or years after the disaster that displaced them. Additional pressure for housing in disaster areas is exacerbated when workers are brought in for rebuilding work and require housing as well.

[0003] While candidate solutions have been proposed to remedy the affordable housing crisis, such as, for example, revitalizing distressed structures, transitioning to smaller housing solutions, incentivizing employers to assist employees with housing costs, and publicly funding construction of affordable rental housing, no solution has emerged that had adequately addressed the problem. Unfortunately, the affordable housing crisis remains pervasive and is getting worse in the United States and around the world.

BRIEF SUMMARY OF THE INVENTION

[0004] According to one aspect of one or more embodiments of the present invention, a 3D printhead for spaying concrete includes a printhead housing configured to attach to a boom or a jib of a mobile platform, a first motor configured to controllably rotate a first directional rotating portion, a second motor disposed on the first directional rotating portion configured to controllably rotate a second directional rotating portion, and a third motor attached to the second directional rotating portion that is configured to controllably rotate a nozzle.

[0005] According to one aspect of one or more embodiments of the present invention, a mobile autonomous printing system for spraying concrete includes a mobile platform, a 3D printhead disposed on a distal end of a boom or a jib of the mobile platform, a mixing tank, a concrete pump in fluid communication with the mixing tank that is configured to communicate concrete to a nozzle of the 3D printhead, and a controller. The controller is configured to control the position of the mobile platform and the placement of the nozzle by controlling a steerable powertrain, controlling the placement and articulation of a boom of the mobile platform, controlling the placement and articulation of the jib of the mobile platform, and directing the concrete pump to pump concrete from the mixing tank to the nozzle while the controller directs the spray of concrete by controlling first and second motors of the 3D printhead. The mobile platform includes the steerable powertrain, a plurality of stabilizers, a base portion, the boom attached to the base portion, and the jib attached to the boom. The 3D printhead includes a printhead housing, the first motor configured to rotate a first directional rotating portion, the second motor disposed on the first directional rotating portion configured to rotate a second directional rotating potion, the third motor attached to the second directional rotating portion configured to controllably rotate the nozzle, and one or more sensors.

[0006] According to one aspect of one or more embodiments of the present invention, a method of printing a concrete structure includes inputting a model having information corresponding to a location of a structure to be printed on a build site, where the structure includes a plurality of panels, with each panel having a wire frame disposed over an insulated material. A location of a mobile platform with a 3D printhead is determined in relation to the build site. For each panel of the structure to be sprayed with concrete, the 3D printhead is positioned in proximity to a panel in accordance with the model. A spatial relationship between the 3D printhead and the panel is calibrated. Concrete is pumped to the 3D printhead which sprays concrete on the panel while moving the 3D printhead to cover the panel with concrete.

[0007] Other aspects of the present invention will be apparent from the following description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 shows a schematic of a mobile autonomous printing system for printing a concrete structure in accordance with one or more embodiments of the present invention.

[0009] Figure 2A shows a front-facing perspective view of a 3D printhead in accordance with one or more embodiments of the present invention.

[0010] Figure 2B shows a front elevation view of the 3D printhead in accordance with one or more embodiments of the present invention.

[0011] Figure 2C shows a rear elevation view of the 3D printhead in accordance with one or more embodiments of the present invention.

[0012] Figure 2D shows a left elevation view of the 3D printhead in accordance with one or more embodiments of the present invention.

[0013] Figure 2E shows a right elevation view of the 3D printhead in accordance with one or more embodiments of the present invention.

[0014] Figure 2F shows a top plan view of the 3D printhead in accordance with one or more embodiments of the present invention.

[0015] Figure 2G shows a bottom plan view of the 3D printhead in accordance with one or more embodiments of the present invention.

[0016] Figure 3 shows a mobile autonomous printing system in accordance with one or more embodiments of the present invention. [0017] Figure 4A shows a perspective view of a portion of an instrumented reinforced insulated panel prior to printing concrete in accordance with one or more embodiments of the present invention.

[0018] Figure 4B shows a perspective view of the portion of the instrumented reinforced insulated panel partially printed with concrete in accordance with one or more embodiments of the present invention.

[0019] Figure 5A shows a plurality of instrumented reinforced insulated panels disposed on the build site that are intended to serve as the foundation of the structure to be printed in accordance with one or more embodiments of the present invention.

[0020] Figure 5B shows instrumented foundation panels partially printed with concreate in accordance with one or more embodiments of the present invention.

[0021] Figure 5C shows instrumented wall panels being installed on the foundation in accordance with one or more embodiments of the present invention.

[0022] Figure 5D shows instrumented wall panels installed on the foundation in accordance with one or more embodiments of the present invention.

[0023] Figure 5E shows a plurality of instrumented roof panels installed on the instrumented wall panels in accordance with one or more embodiments of the present invention.

[0024] Figure 5F shows an exterior side of an instrumented wall panel being printed with concrete in accordance with one or more embodiments of the present invention.

[0025] Figure 5G shows an interior side of an instrumented wall panel being printed with concrete in accordance with one or more embodiments of the present invention.

[0026] Figure 5H shows exterior roof panels being printed with concrete in accordance with one or more embodiments of the present invention.

[0027] Figure 51 shows exterior roof panels being printed with concrete in accordance with one or more embodiments of the present invention.

[0028] Figure 6 shows a schematic of a controller in accordance with one or more embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] One or more embodiments of the present invention are described in detail with reference to the accompanying figures. For consistency, like elements in the various figures are denoted by like reference numerals. In the following detailed description of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention. In other instances, well-known features to one of ordinary skill in the art are not described to avoid obscuring the description of the present invention.

[0030] Conventional 3D printers typically input a model of a device to be printed, partition the model into portions capable of being printed, and then print the device in an additive manner, bit-by-bit, based on the model. The materials vary based on the process but typically include plastics and sometimes metals. However, conventional 3D printers are stationary and are designed to print comparatively small items, typically for prototyping purposes. Several manufacturers have proposed to extend this concept, to some extent, to the construction of concrete structures using an additive deposition process or casting process that forms structures composed entirely of the concrete deposition material.

[0031] For example, Apis Cor’s^® Mobile 3D printing concept is a scaled-up version of a conventional 3D printer with an articulating arm configured to print a wall structure using fiber-reinforced concrete in an additive maimer. Similar to conventional 3D printers, Apis Cor’s^® proposed printer concept is stationary and prints the vertical walls of a structure by depositing concrete bit-by-bit in an additive manner until the wall structure is complete. The resulting structure is entirely composed of the printed material and lacks insulation or metal structural support. In addition, it is only capable of printing the vertical wall components of a structure, not including the roof or an elevated floor as used in a pier and beam foundation.

[0032] Contour Grafting’s^® printing concept is another scaled-up version of a conventional 3D printer that is disposed on a Gantry crane system configured to print a wall structure using concrete in an additive manner. Similar to conventional 3D printers, Contour Grafting’s^® proposed printing concept prints the vertical walls of a structure by depositing concrete bit-by-bit in an additive manner until the wall structure is complete. The resulting structure is entirely composed of the printed material and lacks insulation or metal structural support. In addition, it is only capable of printing the vertical wall components of a structure, not including the roof or an elevated floor as used in a pier and beam foundation.

[0033] WinSun’s^® printing concept is another scaled-up version of a conventional 3D printer that is also disposed on a Gantry crane system configured to print a structure using concrete in an additive manner. Similar to conventional 3D printers, WinSun’s^® proposed printing concept prints the vertical walls of a structure by depositing concrete bit-by-bit in an additive manner until the structure is complete. The resulting structure is entirely composed of the printed material and lacks insulation or metal structural support. In addition, it is only capable of printing the vertical wall components of a structure, not including the roof or an elevated floor as used in a pier and beam foundation.

[0034] Armatron System’s^® printing concept takes a somewhat different approach from the additive deposition concepts discussed above and forms structures using slip-form molding and casting techniques. The resulting structure also lacks insulation or metal structural support.

[0035] Branch Technology’s^® C-FAB^® 3D printer adapts a scaled-up version of a conventional 3D printer and uses proprietary algorithms to form structural members by printing complex geometries that look something akin to wicker patterns. However, the resulting structural members are not solid, lack insulation, and do not include metal structural support.

[0036] CyBe Construction’s^® printing concept adapts a scaled-up version of a conventional 3D printer that is disposed on a mobile platform to print a structure using concrete in an additive manner. Similar to conventional 3D printers, CyBe Construction’s^® proposed printing concept prints the vertical walls of a structure by depositing concrete bit-by-bit in an additive manner until the structure is complete. While mobile, Cybe Construction’s^® 3D concrete printer requires the input of an on-site operator to control the printer and is limited in the types and kinds of structures it can print because of the simplistic pass-through nozzle that delivers the concrete. The resulting structure is entirely composed of the printed material and lacks insulation or metal structural support. In addition, it is only capable of printing the vertical wall components of a structure, not including the roof or an elevated floor as used in a pier and beam foundation. [0037] While the construction industry’s interest in 3D printing continues to grow, none of the proposed solutions to date have achieved the advertised cost savings or other advantages sought. In addition, they have only printed vertical walls of a structure leaving foundations, floors, and roof systems to be done using conventional construction processes. In projects done to date, when all costs are calculated, the use of 3D printing over traditional construction processes has not proven cost effective or even competitive, largely due to the amount of labor required and associated costs of mixing 3D printing with conventional construction processes. In addition, most of the proposed solutions to date require the in-situ placement of what amounts to a scaled-up version of a conventional 3D printer. While some use articulating arms or Gantry cranes, they operate in an additive manner and their range of movement remains limited, requiring the movement of the 3D printer and related equipment during the course of the construction process. While the concept of placing a 3D printer on a mobile platform has been proposed, they merely reduce the amount of labor required to relocate the manually operated printer. These mobile 3D printers must be operated by a controller on site and in many instances, personnel are required to setup, install, position, and remove the mobile 3D printer, foregoing the desired savings by eliminating labor costs. Notwithstanding the above, the proposed solutions to date produce structures using concrete in either an additive deposition process or a casting approach that lack insulation and metal structural support. As such, the proposed solutions to date fall short of reducing costs, reducing labor and associated labor costs, and producing a suitable structure for habitation that can withstand harsh conditions and natural disasters. Moreover, the methods and systems proposed to date have not been able to receive permits and/or certificates of occupancy under the International Code Council (“ICC”) or International Building Code (“IBC”). The IBC is the foundation of the complete family of International Codes and is an essential tool to preserve public health and safety that provides safeguards from hazards associated with the built environment.

[0038] Accordingly, in one or more embodiments of the present invention, a method and system for printing a concrete structure uses a novel 3D printhead disposed on a mobile platform that is capable of autonomously printing a structure on a build site. In contrast to prior proposed solutions, the method contemplates the use of reinforced insulated panels that are disposed on the build site in advance. The reinforced insulated panels provide improved insulation and metal structural support and are sprayed with structural geopolymer concrete that is hydrophobic. Because the 3D printhead includes at least three degrees of freedom in its movement, including the rotation of the nozzle, the system can advantageously print patterns in locations where other simplistic nozzle systems cannot. As such, a resulting structure that is entirely composed of the sprayed concrete material, the method and system produce a structure that includes insulation, metal structural support, and structural geopolymer concrete that improves the insulation, strength, and long-term reliability of the structure.

[0039] The system may be deployed on a build site and operate in an autonomous manner or, be operated at the direction of an operator who may or may not be located on site. A controller of the system may input a model that includes information about the structure to be constructed on the build site. The model may include information relating to the boundary and elevation profile of the build site, dimensional information relating to the structure on the build site, and spatial locations of the panels of the structure to be printed. The controller may then position the mobile platform with 3D printhead in proximity to a panel, and, using one or more sensors disposed on the 3D printhead, verify the location of the panel and the position of the 3D printhead in relation to the panel to calibrate the system. The controller may then spray concrete on the panel while moving the 3D printhead, in any of its degrees of freedom, to cover the panel with concrete. One or more sensors disposed on the 3D printhead, as well as one or more sensors disposed on the panel, may provide information to the controller to ensure that the panel has been adequately sprayed with concrete and, after completion, that it has adequately cured. This process may be repeated for each panel until the structure is complete. Advantageously, a concrete structure may be printed autonomously, substantially lowering the labor costs associated with the construction of the structure.

[0040] Figure 1 shows a schematic of a mobile autonomous printing system 100 for printing a concrete structure in accordance with one or more embodiments of the present invention. System 100 may include a 3D printhead 200 disposed on a mobile platform 300, one or more sensors 210, and a controller 600. A mixing tank 150 may provide concrete (not shown) to a concrete pump 160 that communicates the concrete to 3D printhead 200 at a flow rate directed by controller 600. [0041] In certain embodiments, system 100 may be configured to operate in an autonomous manner. For example, a model 140, such as, for example, a Building Information Modeling (“BIM”) model, may be input to controller 600. Model 140 may include information corresponding to a location of a structure (not shown) to be printed on a build site (not shown), boundary information for the structure and the build site, elevation information for the structure and the build site, dimensional information for the structure and the build site, and spatial location information for the constituent panels (not shown) of the structure to be printed. Using model 140 and one or more sensors (not shown) or devices (not shown) of controller 600, controller 600 may determine the position of system 100, 3D printhead 200, and mobile platform 300 in relation to the build site and the structure to be printed. One or more sensors 210 may be used to calibrate and verify the location of 3D printhead 200 in relation to one or more panels prior to spraying concrete. In autonomous mode, system 100 may position 3D printhead 200 and mobile platform 300 relative to the structure to be printed, enable concrete pump 160 at a desired flow rate, and control 3D printhead 200 to spray concrete on the panel in a desired application, continuing from panel to panel, until the entire structure has been printed. Using one or more sensors 210 disposed on 3D printhead 200 and others embedded in controller 600, 3D printhead 200 and mobile platform 300 may be repositioned for the next panel and to calibrate and verify the location of 3D printhead 200 in relation to the panel to be sprayed. In addition, one or more sensors (not shown) embedded in the panels may provide information to controller 600 regarding a curing state of the printed concrete.

[0042] A remote user 110 may interact with system 100 through user interface 120.

User interface 120 may be a software application resident on controller 600 or a software application that executes on another device (not shown) such as, for example, a smartphone, a tablet, or a laptop computer, that interacts with controller 600 through a wireless or other network connection. Remote user 110 may interact directly with system 100 while on site, remotely through a wireless or cellular connection when not near to mobile platform 300, or remotely through a wireless or cellular connection when not even on site. Data received from one or more sensors or generated by controller 600 may be stored in controller 600 or cloud storage 130. In other embodiments, system 100 may be configured to operate in a semi- autonomous manner. In such embodiments, similar to above, model 140 may be input to controller 600 and used to direct the operation of system 100 as described above. However, a remote user 110 may manage or supervise the operation of system 100 remotely, intervening and making adjustments when needed, to ensure the proper operation of system 100. In still other embodiments, system 100 may be configured to operate based on the direction of remote user 110. Remote user 110 may, through user interface 120, whether on site or remote, control the position and operation of the various components of system 100.

[0043] Figure 2A shows a front-facing perspective view of a 3D printhead 200 in accordance with one or more embodiments of the present invention. The 3D printhead 200 may include a printhead housing 205 that may include one or more mounting interfaces 207 configured to mount 3D printhead 200 to a distal end of a boom (not shown) or a jib (not shown) of a mobile platform (e.g., 300). A main motor 220 may be partially disposed within printhead housing 205 and configured to provide additional torque control on the rotating shaft. The 3D printhead 200 may include a first motor 230 configured to controllably rotate a first directional rotating portion 235. As such, first motor 230 controls the extent to which the first directional rotating portion 235 translates in the x-dimension. The 3D printhead 200 may also include a second motor 240 disposed on the first directional rotating portion 235 configured to controllably rotate a second directional rotating portion 245 in the y-dimension. A third motor 246 may be attached to the second directional rotating portion 245 and configured to controllably rotate a nozzle 250 that is configured to convey concrete through a central lumen disposed therethrough. In certain embodiments, 3D printhead 200 may include one or more sensors 210. For example, sensor 210 may include one or more of a light, camera, and any other type or kind of sensor that helps identify a boundary or determine the distance to an object, including, for example, an optical sensor, a laser sensor, a radar sensor, or an ultrasonic sensor. In addition, a thermal sensor may be used to record temperature of concrete in the process of curing. In this way, 3D printhead 200 may use the light to properly illuminate the object in front of it, the camera may be used to identify the object or detect the edges of the object, and one or more distance sensors may be used to determine the distance to the object. One of ordinary skill in the art will recognize that sensor 210 may be one or more discrete sensors (not shown) or integrated as depicted in the figure. [0044] Continuing, Figure 2B shows a front elevation view of 3D printhead 200 in accordance with one or more embodiments of the present invention. As shown in this view, an output of nozzle 250 is shown facing in the same direction as sensor 210, as would be the case, for example, when 3D printhead 200 is facing a panel to be sprayed with concrete. Sensor 210 may be used to illuminate, identify, detect, or measure the distance to the panel to calibrate the location of 3D printhead 200 in relation to the panel and structure prior to commencing spraying concrete. Continuing, Figure 2C shows a rear elevation view of 3D printhead 200 in accordance with one or more embodiments of the present invention. In this view, an input side of nozzle 250 shown, where a hose that fluidly connects the concrete pump (e.g., 160) to the nozzle 250 may be connected.

[0045] Continuing, Figure 2D shows a left elevation view of 3D printhead 200 in accordance with one or more embodiments of the present invention. In this view, the relationship between first motor 230 and first directional rotating portion 235 and second motor 240 and second directional rotating portion 245 may be more clearly seen. In operation, first motor 230 may controllably rotate first directional rotating portion 235 in the x-dimension. Similarly, second motor 240 may controllably rotate second directional rotating portion 245 in the y-dimension. A bearing 247 may connect first directional rotating portion 235 to second directional rotating portion 245. Third motor 246 may controllably rotate nozzle 250. As such, the controller (e.g., 600) has at least three degrees of freedom and the ability to rotate nozzle 250 enabling substantial control over the manner in which concrete is sprayed. Continuing, Figure 2E shows a right elevation view of 3D printhead 200 in accordance with one or more embodiments of the present invention. Continuing, Figure 2F shows a top plan view of 3D printhead 200 in accordance with one or more embodiments of the present invention. Continuing, Figure 2G shows a bottom plan view of 3D printhead 200 in accordance with one or more embodiments of the present invention. One of ordinary skill in the art will recognize that the size, shape, and configuration of 3D printhead 200 may vary based on an application or design in accordance with one or more embodiments of the present invention.

[0046] Figure 3 shows a mobile autonomous printing system 100 configured for printing a concrete structure in accordance with one or more embodiments of the present invention. Mobile platform 300 may include a steerable powertrain 310, a base portion 315, a plurality of stabilizers 320, an articulating boom 330, an optional jib 340 that may or may not articulate, and a 3D printhead 200 disposed on a distal end of boom 330 or jib 340. Powertrain 310 may include all of the components that generate the power that causes mobile platform 300 to move as directed by a controller 600 (reference numeral showing location only) and may include an engine (not shown), a transmission (not shown), a drive shaft (not shown), one or more differentials (not shown), and a drive system that contacts the surface. The plurality of stabilizers 320 may be disposed on base portion 315 and, at the direction of controller 600, may be configured to controllably deploy when stabilization is required or controllably retract to reduce the width-wise footprint of platform 300 when moving, thereby allowing it to more easily fit through a narrow passage such as a 36” door frame. Articulating boom 330 may be disposed on base portion 315 and, at the direction of controller 600, controllably rotate at the base about a vertical axis (azimuth) and the angle of elevation (altitude) may be controllably adjusted, similar to, for example, a two-axis altitude-azimuth mount. A distal end of articulating boom 330 may, at the direction of controller 600, controllably articulate, thereby extending the length of boom 330. A first distal end of jib 340 may be disposed on the distal end of articulating boom 330. In certain embodiments, jib 340 may, at the direction of controller 600, controllably articulate, thereby extending the length of jib 340. The 3D printhead 200 may be disposed on boom 330 or the second distal end of jib 340. A hose 350 may fluidly connect the concrete pump (e.g., 160) to nozzle 250 of 3D printhead 200.

[0047] While the mobile platform 300 depicted in the figure is merely exemplary, one of ordinary skill in the art will recognize that any mobile platform capable of being conveyed and controlled by a remote user via a user interface (e.g., 120) to a controller 600 that is suitable for hosting 3D printhead 200 may be used in accordance with one or more embodiments of the present invention.

[0048] Figure 4A shows a perspective view of a portion of an instrumented reinforced insulated panel 400 prior to printing concrete in accordance with one or more embodiments of the present invention. For purposes of illustration, one or more panels 400 may be used for a variety of structural applications including the construction of load-bearing walls, floor slabs, and roof slabs. Panel 400 may include a metal wire frame 420 disposed over a core of insulated material 410. The composition of insulated material 410 may vary based on an application or design. For example, in certain embodiments, structural panels manufactured by Panel W include a plastic foam polyurethane material that is durable, lightweight, and insulates temperature and noise. In other embodiments, polystyrene may be used as the core insulation material 410. In still other embodiments, dense or structurally improved polyurethane may be used as the core insulation material 410, which may provide improved insulation of temperature and noise over that of polystyrene. The size, shape, thickness and configuration of insulated material 410 may vary based on the application or design. For example, thicker walls may include a thicker core of insulated material 410. Metal wire frame 420 may be disposed over, around, or even through insulated material 410 to provide additional reinforcement to the concrete. The composition of metal wire frame 420 may also vary based on an application or design. For example, in certain embodiments, structural panels manufactured by Panel W^® include a steel wire frame 420. In other embodiments, panels 400 may include a wire frame 420 composed of steel alloy. In still other embodiments, panels 400 may include a wire frame 420 composed of a different metal alloy. In certain embodiments, one or more sensors 430 may be attached to either metal wire frame 420 or a surface of insulated material 410 (not shown). Sensor 430 may be a wireless concrete sensor configured to be embedded in concrete that monitors and reports the drying and curing of the applied concrete to the controller (e.g., 600) in real time. For example, sensor 230 may measure and wirelessly report temperature and relative humidity that enable the controller (e.g., 600) to determine the state of drying and curing of the applied concrete.

[0049] Continuing, Figure 4B shows a perspective view of the portion of the instrumented reinforced insulated panel 400 partially 3D printed with concrete 440 in accordance with one or more embodiments of the present invention. As discussed herein, the 3D printhead (e.g., 200) may be placed in proximity with panel 400 and use one or more sensors (e.g., 210) to calibrate and verify its position relative to panel 400 prior to spraying concrete 440. While spraying concrete 440 on panel 400, the 3D printhead (e.g., 200) may move in any one or more of the degrees of freedom and the nozzle may be rotated as desired to control the application of concrete 440 to panel 400. Once concrete 440 has been applied and covers sensor 430, the controller (e.g., 600) may monitor the drying and curing state of concrete 440. As noted above, panel 400 may be used as a load-bearing wall, a floor slab, or roof slab. One or more ties or wires (not shown) may be used to hold adjacent panels 400 together prior to the application of concrete 440. When used as floor slabs, exposed rebar (not shown) may be used to connect the floor slab to a structural wall panel 400. One of ordinary skill in the art will recognize that structural panel 400 may vary in shape, size, and thickness, the metal wire frame 420 may vaiy in shape, size, pitch, and pattern, and insulated material 410 may vaiy in shape, size, and thickness, and the location of one or more sensors 430 may vary based on an application or design in accordance with one or more embodiments of the present invention. Once cured, one or more sensors (not shown) may monitor the flex of the walls and be able to provide data to establish correlation between strong winds, flooding events, and earthquakes to establish the relative strength of the wall, floor, and roof systems compared to the relative strength of the event resulting in potentially lower hazard insurance rates for the structure.

[0050] Figure 5A shows a plurality of instrumented reinforced foundation panels 400 disposed on the build site that are intended to serve as the foundation 500 of the structure to be printed in accordance with one or more embodiments of the present invention. As discussed above, a model (e.g., 140) may be generated that includes information about the structure to be constructed on the build site. The model may include information relating to the boundary and elevation of the build site, dimensional information relating to the foundation and the structure in relation to the build site, and spatial locations of the foundation and the structure to be printed. In certain embodiments, foundation 500 may be formed by disposing a plurality of foundation panels 400 on the build site according to the model (e.g., 140). For example, the model (e.g., 140) may specify an exact co-ordinate location for the placement of the panels 400. Each foundation panel 400 may include a wire frame (e.g., 420) disposed over and/or through an insulated material (e.g., 410) and may include a plurality of rebar 504 extending from the wire frame (e.g., 420) for connection to structural panels (not shown). One or more sensors 430 may be disposed on each panel 400 to communicate the drying and curing state of the concrete after application. One of ordinary skill in the art will recognize that while the method disclosed herein contemplates the ability to print a foundation 500, the foundation 500 may be constructed using conventional construction processes (not shown) or already exist on the build site (not shown).

[0051] Continuing, Figure 5B shows the plurality of instrumented foundation panels

400 that are intended to serve as foundation 500 partially printed with concrete in accordance with one or more embodiments of the present invention. Using the model (e.g., 140), the controller (e.g, 600) may position mobile platform 300 with 3D printhead 200 in proximity to a foundation panel 400 in accordance with the model (e.g., 140). The controller (e.g., 600) may include one or more of a GPS device (not shown), a network device (not shown), an altimeter (not shown), a gyroscope (not shown), and a camera (e.g., 210) that may be used to precisely locate the position and orientation of mobile platform 300 within the build site and in relation to panels 400. Once mobile platform 300 is positioned and stabilized 320 in place, one or more of articulating boom 330, articulating jib 340, and one or more of the motors (e.g., 230, 240) of 3D printhead 200 may be controlled by the controller (e.g., 600) to properly place 3D printhead 200 with respect to the panel 400 to be printed. One or more sensors (e.g., 210) may calibrate a spatial relationship between nozzle 350 and 3D printhead 200 with respect to the panel 400. The controller (e.g., 600) may adjust the location of 3D printhead 200 as necessary to ensure nozzle 250 is in the desired location with respect to the model (e.g., 140) and by sensor data, the actual panel 400 before it. The controller (e.g., 600) may then engage the concrete pump (e.g., 160) to pump concrete to nozzle 250 of 3D printhead 200 via hose 350. The nozzle 250 of 3D printhead 200 may spray concrete on panel 400 while moving 3D printhead 200 or nozzle 250 to ensure coverage of panel 400 with concrete. The controller (e.g., 600) may continue to position mobile platform 300 and nozzle 250 of 3D printhead 200 to spray concrete on uncovered areas of the panel 400 while moving 3D printhead 200 to cover all uncovered areas of the foundation panels 400.

[0052] Continuing, Figure 5C shows a plurality of instrumented wall panels 400 being installed on printed foundation 510 in accordance with one or more embodiments of the present invention. In certain embodiments, wall panels 400 may be identical, or substantially similar, to foundation panels 400. In other embodiments, wall panels 400 may vary from foundation panels 400 in size, shape, thickness, or composition of the wire frame (e.g., 420) and the insulated material (e.g., 410) that forms its core. One or more wall panels 400 may be placed on printed foundation 510 in accordance with the model (e.g., 140) by one or more construction workers (not shown) on site. Each wall panel 400 may be connected to exposed portions of one or more rebar 504 members that connect the wire frame (e.g., 420) or the insulated material (e.g., 410) of one or more foundation panels 400 of printed foundation 510 to the wire frame (e.g., 420) or the insulated material (e.g, 410) of the wall panel 400 being installed. Joints between adjacent wall panels 400 may be tied together with ties or wire (not shown) prior to the application of concrete. One or more sensors 430 may be disposed on each wall panel 400 to communicate the drying and curing state of the concrete after application. Continuing, Figure 5D shows a plurality of instrumented wall panels 400 installed on foundation 510 in accordance with one or more embodiments of the present invention. The process of placing one or more wall panels 400 may continue until all wall panels 400 are placed and connected to printed foundation 510. Each wall panel 400 may include one or more sensors 430 configured to wirelessly communicate the drying and curing state of the concrete after application and may optionally include one or more sensors (not shown) configured to wireless communicate structural performance information relating to, for example, sway.

[0053] Continuing, Figure 5E shows a plurality of instrumented roof panels 400 installed on the instrumented wall panels 400 in accordance with one or more embodiments of the present invention. In certain embodiments, roof panels 400 may be identical, or substantially similar, to wall panels 400. In other embodiments, roof panels 400 may vary from wall panels 400 in size, shape, thickness, or composition of the wire frame (e.g., 420) and the insulated material (e.g., 410) that forms its core. One or more roof panels 400 may be placed on one or more wall panels 400 in accordance with the model (e.g, 140) by one or more construction workers (not shown) on site. Each roof panel 400 may be connected to one or more wall panels 400 by ties or wire (not shown) prior to the application of concrete. One or more sensors 430 may be disposed on each panel 400 to communicate the drying and curing state of the concrete after application. With all of the panels 400 disposed in place in accordance with the model (e.g., 140), the mobile printing system 100 may be deployed to apply concrete.

[0054] Continuing, Figure 5F shows an exterior side of an instrumented wall panel

400 being printed with concrete in accordance with one or more embodiments of the present invention. Once positioned within the build site, the controller (e.g, 600) may determine a location and orientation of the mobile platform 300 with 3D printhead 200 in relation to the build site. For each panel to be sprayed with concrete, the controller (e.g., 600) may use one or more of a GPS device (not shown), a network device (not shown), an altimeter (not shown), a gyroscope (not shown), and a camera (e.g., 210) to precisely position and orientate mobile platform 300 within the build site in relation to one or more panels 400 to be printed. The controller (e.g., 600) may then determine a location and orientation of mobile platform 300 with 3D printhead 200 in proximity to the one or more panels 400 to be sprayed with concrete in reference to the model (e.g., 140). Once mobile platform 300 is positioned in an appropriate location, one or more stabilizers 320 may be deployed to stabilize system 100. Then the controller (e.g., 600) may position 3D printhead 200 in proximity to the panel 400 to be printed in accordance with the model (e.g., 140). For example, the controller (e.g., 600) may manipulate one or more of articulating boom 330, articulating jib 340, one or more motors (e.g., 230, 240) of 3D printhead 200, and nozzle 250 so that nozzle 250 is positioned in an appropriate location, in accordance with the model (e.g., 140), for spraying the panel 400 with concrete. One or more sensors 210 may be used to calibrate and verify the spatial relationship between nozzle 250 of 3D printhead 200 and one or more panels 400 to be sprayed with concrete. If sensor data (not shown) indicates nozzle 250 is not in an appropriate location with respect to the model (e.g., 140), the controller (e.g., 600) may adjust the location and positioning of nozzle 250 or 3D printhead 200, and if needed, mobile platform 300. In the event, there is a discrepancy between an actual location of a panel 400 and the expected location of the panel 400 indicated by the model (e.g., 140), the controller (e.g., 600) may rely primarily on sensor data (not shown) obtained by the sensors (e.g., 210) of 3D printhead 200 or a combination of sensor data (not shown) and the model (e.g., 140) to ensure the proper placement of nozzle 250 in relation to the panel 400 to be printed.

[0055] In autonomous mode, the controller (e.g., 600) may enable the concrete pump

(e.g, 160) to a desired flow rate, and control nozzle 250 and 3D printhead 200 to spray concrete on the panel 400 in a desired application, continuing from panel to panel, until the entire structure has been printed. Using one or more sensors (e.g., 210) disposed on 3D printhead 200 and embedded in controller 600, 3D printhead 200 and, if needed, mobile platform 300 may be repositioned for the next panel 400 and to calibrate and verify the location of 3D printhead 200 in relation to the next panel 400 to be sprayed. In addition, one or more sensors 430 embedded in the panels 400 may provide information to controller 600 regarding the drying and curing state of the printed concrete walls 520. A remote user (e.g., 110) may interact with system 100 through the user interface (e.g., 120) of the controller (e.g., 600). The remote user (e.g., 110) may interact directly with system 100 while on site, remotely through a wireless or cellular connection (not shown) when not adjacent to mobile platform 300, or remotely through a wireless or cellular connection when not even on site. Data received from one or more sensors or generated by the controller (e.g., 600) may be stored in the controller (e.g., 600) or cloud storage (e.g., 130). In other embodiments, system 100 may be configured to operate in a semi -autonomous manner. In such embodiments, similar to above, the model (e.g., 140) may be input to the controller (e.g., 600) and used to direct the operation of system 100 as described above. However, a remote user (e.g., 110) may manage or supervise the operation of system 100 remotely, intervening and making adjustments when needed, to ensure the proper operation of system 100. In still other embodiments, system 100 may be configured to operate based on the direction of a remote user (e.g., 110). The remote user (e.g., 110) may, through the user interface (e.g., 120), whether on site or remote, control the position and operation of the various components of system 100.

[0056] Once applied, one or more sensors (e.g., 210) of 3D printhead 200 may be used to validate the spraying operation was successfully performed. If there are areas that were missed or otherwise weren’t sufficiently coated with concrete, the controller (e.g., 600) may direct the system 100 to spray concrete on one or more uncovered areas of a panel 400 while moving 3D printhead 200 in the manner needed to cover the uncovered areas with concrete.

[0057] Continuing, Figure 5G shows an interior side of an instrumented wall panel

400 being printed with concrete in accordance with one or more embodiments of the present invention. The one or more stabilizers 320 may be folded up and mobile platform 300 may be maneuvered through, for example, a 36” door frame, to an interior portion of the structure. Once inside, similar to as described above, the system 100 may spray concrete on the interior wall panels 400 of the structure. Once concrete has been applied, the controller (e.g., 600) may receive data from one or more sensors (e.g., 430) that communicate information corresponding to the drying and curing state of the applied concrete. The information may include, for example, information relating to temperature and relative humidity. The controller (e.g., 600) may use the curing state information to control a timing for applying concrete. For example, the controller (e.g., 600) may wait to spray concrete on the roof panels 400 until after the printed walls 520 have sufficiently cured as indicated by one or more wireless curing sensors 430 embedded in the printed walls 520.

[0058] Continuing, Figure 5H shows an exterior side of a roof panel 400 being printed with concrete in accordance with one or more embodiments of the present invention. Once the printed walls 520 have sufficiently cured, the system 100 may, if still located on the interior of the structure, print the interior sides (not shown) of the roof panels 400. The controller (e.g, 600) may direct the system to print the roof panels 400 with concrete, similar as described above with respect to the foundation panels 400 and wall panels 400. Continuing, Figure 51 shows an exterior side of a roof panel 400 being printed with concrete in accordance with one or more embodiments of the present invention. Once complete, the controller (e.g., 600) may monitor the drying and curing state of printed wall panels 530.

[0059] In one or more embodiments of the present invention, a specific type of concrete may be used to facilitate construction of the structure to high standards. In certain embodiments, the concrete used in the construction of the structure may be geopolymer concrete, such as that manufactured by Geopolymer Solutions^®. Geopolymer concrete is hydrophobic, does not exhibit cold joints like Portland Cement, is two to three times as strong as Portland Cement, cures quickly, and endures for many decades, potentially even centuries. By using the combination of a reinforced insulated core panel with geopolymer concrete, the resulting structure may be able to withstand wind of 220 miles per hour or more, may withstand earthquakes in excess of 8.0 on the Richter scale, will not bum, does not require significant maintenance, and will last for many decades, if not centuries.

[0060] Figure 6 shows a schematic of a controller 600 in accordance with one or more embodiments of the present invention. In one or more embodiments of the present invention, controller 600 may be disposed as part of the mobile autonomous printing system (e.g., 100), typically as part of a user accessible area of the mobile platform (e.g., 300) where manual controls may be located. Controller 600 may include one or more central processing units (singular“CPU” or plural“CPUs”) 605, host bridge 610, input/output (“IO”) bridge 615, graphics processing units (singular “GPU” or plural “GPUs”) 625, and/or application-specific integrated circuits (singular“ASIC or plural“ASICs”) (not shown) disposed on one or more printed circuit boards (not shown) that are configured to perform computational operations. Each of the one or more CPUs 605, GPUs 625, or ASICs (not shown) may be a single-core (not independently illustrated) device or a multi-core (not independently illustrated) device. Multi-core devices typically include a plurality of cores (not shown) disposed on the same physical die (not shown) or a plurality of cores (not shown) disposed on multiple die (not shown) that are collectively disposed within the same mechanical package (not shown).

[0061] CPU 605 may be a general-purpose computational device typically configured to execute software instructions. CPU 605 may include an interface 608 to host bridge 610, an interface 618 to system memory 620, and an interface 623 to one or more IO devices, such as, for example, one or more GPUs 625. GPU 625 may serve as a specialized computational device typically configured to perform graphics functions related to frame buffer manipulation. However, one of ordinary skill in the art will recognize that GPU 625 may be used to perform non-graphics related functions that are computationally intensive. In certain embodiments, GPU 625 may interface 623 directly with CPU 625 (and interface 618 with system memory 620 through CPU 605). In other embodiments, GPU 625 may interface 621 with host bridge 610 (and interface 616 or 618 with system memory 620 through host bridge 610 or CPU 605 depending on the application or design). In still other embodiments, GPU 625 may interface 633 with IO bridge 615 (and interface 616 or 618 with system memory 620 through host bridge 610 or CPU 605 depending on the application or design). The functionality of GPU 625 may be integrated, in whole or in part, with CPU 605.

[0062] Host bridge 610 may be an interface device configured to interface between the one or more computational devices and IO bridge 615 and, in some embodiments, system memory 620. Host bridge 610 may include an interface 608 to CPU 605, an interface 613 to IO bridge 615, for embodiments where CPU 605 does not include an interface 618 to system memory 620, an interface 616 to system memory 620, and for embodiments where CPU 605 does not include an integrated GPU 625 or an interface 623 to GPU 625, an interface 621 to GPU 625. The functionality of host bridge 610 may be integrated, in whole or in part, with CPU 605. IO bridge 615 may be an interface device configured to interface between the one or more computational devices and various IO devices (e.g., 640, 645) and IO expansion, or add-on, devices (not independently illustrated) including, but not limited to, a GPS device. IO bridge 615 may include an interface 613 to host bridge 610, one or more interfaces 633 to one or more IO expansion devices 635, an interface 638 to keyboard 640, an interface 643 to mouse 645, an interface 648 to one or more local storage devices 650, and an interface 653 to one or more network interface devices 655. The functionality of IO bridge 615 may be integrated, in whole or in part, with CPU 605 or host bridge 610. Each local storage device 650, if any, may be a solid-state memory device, a solid-state memory device array, a hard disk drive, a hard disk drive array, or any other non-transitory computer readable medium. Network interface device 655 may provide one or more network interfaces including any network protocol suitable to facilitate networked communications.

[0063] Controller 600 may include one or more network-attached storage devices 660 in addition to, or instead of, one or more local storage devices 650. Each network- attached storage device 660, if any, may be a solid-state memory device, a solid- state memory device array, a hard disk drive, a hard disk drive array, or any other non-transitory computer readable medium. Network-attached storage device 660 may or may not be collocated with controller 600 and may be accessible to controller 600 via one or more network interfaces provided by one or more network interface devices 655.

[0064] One of ordinary skill in the art will recognize that controller 600 may be a conventional computing system or an application-specific computing system (not shown). In certain embodiments, an application-specific computing system (not shown) may include one or more ASICs (not shown) that are configured to perform one or more specialized functions in a more efficient manner. The one or more ASICs (not shown) may interface directly with CPU 605, host bridge 610, or GPU 625 or interface through IO bridge 615. Alternatively, in other embodiments, an application-specific computing system (not shown) may be reduced to only those components necessary to perform a desired function in an effort to reduce one or more of chip count, printed circuit board footprint, thermal design power, and power consumption. The one or more ASICs (not shown) may be used instead of one or more of CPU 605, host bridge 610, IO bridge 615, or GPU 625. In such systems, the one or more ASICs may incorporate sufficient functionality to perform certain network and computational functions in a minimal footprint with substantially fewer component devices.

[0065] As such, one of ordinary skill in the art will recognize that CPU 605, host bridge 610, IO bridge 615, GPU 625, or ASIC (not shown) or a subset, superset, or combination of functions or features thereof, may be integrated, distributed, or excluded, in whole or in part, based on an application, design, or form factor in accordance with one or more embodiments of the present invention. Thus, the description of controller 600 is merely exemplary and not intended to limit the type, kind, or configuration of component devices that constitute a controller 600 suitable for performing computing operations in accordance with one or more embodiments of the present invention. Notwithstanding the above, one of ordinary skill in the art will recognize that controller 600 may be a standalone, laptop, tablet, desktop, industrial, server, blade, or rack mountable system and may vary based on an application or design.

[0066] Advantages of one or more embodiments of the present invention may include one or more of the following:

[0067] In one or more embodiments of the present invention, a method and system for printing a concrete structure uses a 3D printhead disposed on a mobile platform that is capable of autonomously printing a structure on a build site using reinforced insulated panels. The reinforced insulated panels may be disposed on the build site in advance and provide improved insulation and structural support. The panels may be sprayed with geopolymer concrete that is hydrophobic resulting in a structure that is well insulated, fire resistant, and protected from wind and water events.

[0068] In one or more embodiments of the present invention, a method and system for printing a concrete structure provides a solution that minimizes the amount of labor, and associated costs, with constructing a structure. Using a combination of wireframe reinforced insulation cores as structural panels, a mobile autonomous printing system uses an inputted model and one or more sensors to apply geopolymer concrete to the panels and then monitors the drying and curing state of the concrete. While limited labor may be required to install the panels prior to concrete printing, once the unprinted structure is installed on the build site in accordance with the model, the mobile autonomous printing system may perform the remaining work of applying the geopolymer concrete.

[0069] In one or more embodiments of the present invention, a method and system for

3D printing a concrete structure uses a nozzle disposed as part of a 3D printhead that includes at least three degrees of freedom, including the rotation of the nozzle, allowing for precise application of concrete, in locations typically not accessible, as well as the application of concrete in unique patterns for aesthetic or structural purposes. The 3D printhead may be disposed on a mobile platform capable of being controlled by a controller.

[0070] In one or more embodiments of the present invention, a method and system for

3D printing a concrete structure constructs improved structures over those printed with conventional 3D printer technology adapted for additive deposition of cast molding of concrete.

[0071] In one or more embodiments of the present invention, a method and system for

3D printing a concrete structure reduces labor and material costs associated with construction of a structure.

[0072] In one or more embodiments of the present invention, a method and system for

3D printing a concrete structure reduces the amount of time required to construct a structure. Because the mobile autonomous printing system does not require a break, it may work as long as needed to complete the task at hand.

[0073] In one or more embodiments of the present invention, a method and system for

3D printing a concrete structure reduces the cost associated with maintenance of the structure of the course of the life of the structure.

[0074] In one or more embodiments of the present invention, a method and system for

3D printing a concrete structure produces a low-cost structure that can withstand hurricane force winds and earthquakes and is fire resistant and hydrophobic.

[0075] While the present invention has been described with respect to the above- noted embodiments, those skilled in the art, having the benefit of this disclosure, will recognize that other embodiments may be devised that are within the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the appended claims.

Claims

CLAIMS What is claimed is:

1. A method of printing a concrete structure comprising:

inputting a model comprising information corresponding to a location of a structure to be printed on a build site, wherein the structure comprises a plurality of panels, each panel comprising a wire frame disposed over an insulated material;

determining a location of a mobile platform with a 3D printhead in relation to the build site; and

for each panel of the structure to be sprayed with concrete:

positioning the 3D printhead in proximity to a panel in accordance with the model,

calibrating a spatial relationship between the 3D printhead and the panel, pumping concrete to the 3D printhead, and

spraying concrete on the panel with the 3D printhead while moving the 3D printhead to cover the panel with concrete.

2. The method of claim 1, further comprising:

positioning the mobile platform with the 3D printhead in proximity to the panel in accordance with the model.

3. The method of claim 1, further comprising:

verifying the concrete sprayed on the panel covered the panel to a required thickness.

4. The method of claim 1, further comprising: spraying concrete on uncovered areas of the panel with the 3D printhead while moving the 3D printhead to cover the uncovered areas of the panel.

5. The method of claim 1, further comprising:

verifying the concrete sprayed on the panel has cured in accordance with

predetermined specifications.

6. The method of claim 1, further comprising:

disposing a plurality of foundation panels on the build site according to the model, wherein each foundation panel comprises a wire frame disposed over a insulated material;

spraying concrete on the plurality of foundation panels in accordance with the model;

and

verifying the concrete sprayed on the foundation panels has cured in accordance with predetermined specifications;

7. The method of claim 1, further comprising:

disposing the plurality of panels on a foundation.

8. The method of claim 1, wherein the concrete comprises geopolymer concrete.

9. The method of claim 1, wherein the model comprises a building information model.

10. The method of claim 1, wherein the model comprises elevation information, dimensional information relating to the build site, and spatial locations of the panels of the structure.

11. The method of claim 1, wherein moving the 3D printhead comprises moving an articulating boom of the mobile platform.

12. The method of claim 1, wherein moving the 3D printhead comprises moving an articulating jib of the mobile platform.

13. The method of claim 1, wherein moving the 3D printhead comprises moving an articulating jib of the mobile platform.

14. The method of claim 1, wherein moving the 3D printhead comprises moving a first directional rotating portion of the 3D printhead.

15. The method of claim 1, wherein moving the 3D printhead comprises moving a second directional rotating portion of the 3D printhead.

16. The method of claim 1, wherein moving the 3D printhead comprises rotating a nozzle of the 3D printhead.

17. A 3D printhead for spaying concrete comprising:

a printhead housing configured to attach to a jib of a mobile platform;

a first motor configured to controllably rotate a first directional rotating portion;

a second motor disposed on the first directional rotating portion configured to

controllably rotate a second directional rotating portion; and a third motor attached to the second directional rotating portion configured to controllably rotate a nozzle.

18. The 3D printhead of claim 17, further comprising:

a sensor comprising one or more of a light, a camera, and a distance measuring

sensor.

19. A system for spraying concrete comprising:

a mobile platform comprising:

a steerable powertrain,

a plurality of stabilizers,

a base portion,

a boom attached to the base portion, and

a jib attached to the boom;

a 3D printhead disposed on a distal end of the jib comprising:

a printhead housing,

a first motor configured to rotate a first directional rotating portion, a second motor disposed on the first directional rotating portion configured to rotate a second directional rotating portion,

a third motor attached to the second directional rotating portion configured to controllably rotate a nozzle,

a sensor;

a mixing tank;

a concrete pump in fluid communication with the mixing tank configured to communicate concrete to the nozzle; and a controller configured to control a position of the mobile platform by controlling the steerable powertrain, controlling a placement and articulation of the boom and the jib, and directing the concrete pump to pump concrete from the mixing tank to the nozzle while the controller directs the spray of concrete by controlling the first, second, and third motors.

20. The system of claim 19, wherein the controller positions the 3D printhead in proximity to a panel in accordance with a model, calibrating a spatial relationship between the 3D printhead and the panel with the camera or sensor, and sprays concrete on the panel with the 3D printhead while moving the 3D printhead to cover the panel with concrete.