Metal-concrete composite additive manufacturing system

Abstract

The application provides a metal-concrete composite additive manufacturing system, and relates to the technical field of additive manufacturing. The system comprises a concrete printing module, a metal printing module and a central control system. The concrete printing module is used for performing layer accumulation printing and jet printing of concrete materials, the metal printing module is used for performing electric arc additive manufacturing of metal materials, and the central control system is used for generating a composite printing path planning and a composite process control strategy containing a metal printing path and a concrete printing path according to the characteristics of time sequence and space of a composite process, and controlling the concrete printing module to perform printing of concrete materials, the metal printing module to perform electric arc additive manufacturing of metal materials, and the parameters of the composite process to be controlled in the composite printing process, so as to complete the integrated construction of a reinforced concrete composite structure. The system can improve the scale flexibility and process integration of composite printing.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, specifically to a metal-concrete composite additive manufacturing system. Background Technology

[0002] In existing additive manufacturing technologies, concrete printing equipment and metal printing equipment are typically designed independently, making it difficult to achieve composite construction of the two materials on the same machine. Concrete 3D printing often employs gantry or truss structures, limiting its printing range to the gantry span. Once the equipment is installed, the printing size is essentially fixed and cannot be flexibly adjusted according to the component dimensions. When printing ultra-large-scale (e.g., 100-meter-scale) architectural components, multiple machines are often required for segmented splicing operations, increasing equipment costs and space requirements, and easily leading to seam defects in the splicing area. On the other hand, metal arc additive manufacturing equipment typically uses small robotic arms or desktop machine tools, limiting the printing size to within the meter level, making it difficult to directly apply to engineering construction. While existing mobile printing equipment offers some mobility, its positioning accuracy and load capacity are limited, making it unable to independently complete high-precision, large-size metal-concrete composite printing tasks.

[0003] Furthermore, metal printing and concrete printing differ significantly in their process characteristics: metal arc printing requires precise control of the molten pool temperature and welding parameters, while concrete extrusion printing relies on a continuous feeding system and stable pumping pressure. Current technologies lack solutions that can effectively integrate these two different printing processes into a single control system, resulting in metal and concrete printing often having to be performed independently, in different times and areas, making true collaborative manufacturing difficult. Even the few attempts to embed metal reinforcement into concrete components mostly employ a crude method of printing concrete first and then manually placing the metal reinforcement, or simply installing the metal and concrete print heads side-by-side without addressing spatial interference and thermal impact issues. Therefore, existing composite additive manufacturing solutions are significantly insufficient in terms of printing scale flexibility and the integration of metal-concrete processes, making it difficult to meet the demands for high-efficiency, high-quality integrated forming of large and complex components. Summary of the Invention

[0004] Based on this, this application provides a metal-concrete composite additive manufacturing system that can improve the dimensional flexibility and process integration of composite printing.

[0005] Metal-concrete composite additive manufacturing system: concrete printing module, metal printing module, and central control system;

[0006] The concrete printing module is used to perform lamination printing and jet printing of concrete materials, and the metal printing module is used to perform arc additive manufacturing of metal materials. The central control system is used to generate composite printing path planning and composite process control strategy, which includes metal printing path and concrete printing path, based on the temporal and spatial characteristics of the composite process. Based on the composite printing path planning, the system controls the concrete printing module to print concrete material, controls the metal printing module to perform arc additive manufacturing of metal material, and performs parameter control of the composite process during the composite printing process to complete the integrated construction of reinforced concrete composite structure.

[0007] Optionally, the system further includes a gantry printer, which includes a gantry frame and ground rails; the movement paths of the gantry frame are arranged in parallel; a transverse rail is provided between the movement paths, and a transverse trolley is provided on the transverse rail; the gantry frame can move along the ground rails to the transverse trolley, and the transverse trolley can move along the transverse rails; the transverse trolley is used to move the gantry frame from one set of ground rails to another set of ground rails; the gantry frame is connected to at least one robotic arm, which can move along the gantry frame crossbeam and can selectively mount a concrete print head or a metal print head.

[0008] Optionally, the central control system is specifically configured to: during the composite printing process, control the metal printing module to melt and deposit metal material layer by layer or segment to form a steel reinforcement skeleton or metal structure layer, and control the concrete printing module to print concrete material inside or outside the already formed steel reinforcement skeleton or metal structure layer, so that metal printing and concrete printing are performed alternately in a preset order.

[0009] Optionally, the metal printing module includes an arc welding gun, a wire feeding mechanism, a welding power source, a hot wire power source, a water cooling device, and a protective gas supply device; the concrete printing module includes a concrete pumping system, an extrusion nozzle, and a material mixing device. The central control system is electrically connected to the arc welding gun, wire feeding mechanism, welding power source, shielding gas supply device, concrete pumping system, extrusion nozzle and material mixing device, respectively. It is used to control the metal printing module to form a steel reinforcement skeleton or metal structure layer in a preset alternating sequence, and to control the concrete printing module to print concrete material inside, outside or between layers of the steel reinforcement skeleton or metal structure layer.

[0010] Optionally, the central control system includes a gantry frame control submodule, a track rotation motion control submodule, a robotic arm motion control submodule, and a composite process control module; The gantry frame control submodule is used to control the gantry frame's moving speed, moving position, and acceleration / deceleration curve along the ground rail, and to control the precise positioning of the gantry frame at the docking point of the transverse track. The track-switching motion control submodule is used to control the movement of the traverse trolley along the traverse track, and to control the unlocking of the gantry frame from the current ground rail, the docking and locking of the traverse trolley, and the relocking and coordinate mapping update of the gantry frame on the target ground rail. The robotic arm motion control submodule is used to control the movement path of the robotic arm along the crossbeam of the gantry frame and the spatial trajectory of the robotic arm end effector. The composite process control module is used to control the printing process parameters of the concrete print head or the metal print head, including extrusion speed, wire feeding speed, welding current and voltage, and multi-welding gun coordination.

[0011] Optionally, the central control system is further configured for composite additive collaborative control, including: When generating the composite printing path plan, a heat-affected zone is set for each metal printing segment, and the spatial path of the subsequent concrete printing segment is made to avoid the heat-affected zone; a forced waiting time is set for each metal printing segment, and the starting point of the forced waiting time is the end time of the most recent concrete printing.

[0012] Optionally, the central control system also includes master-slave collaborative control, including: When the first gantry crane needs to enter the current working area of ​​the second gantry crane, the central control system issues an avoidance command to the second gantry crane, controlling the second gantry crane to move along the ground rail to a preset waiting position; The central control system receives the ready signal from the second gantry crane and, after confirming that the work area is cleared, sends an entry permission signal to the first gantry crane, controlling the first gantry crane to enter the work area.

[0013] Optionally, the master-slave collaborative control further includes: After the first gantry frame enters the work area, when the first robotic arm driving the concrete printing head is about to enter the work sub-area of ​​the second robotic arm driving the metal printing head and the spatial distance is less than the minimum safe space distance, an intrusion request signal is sent to the second robotic arm. Before receiving the permission signal issued by the second robotic arm in response to the intrusion request signal, control the second robotic arm to interrupt the current metal printing task and retreat to a safe waiting position; Upon receiving the permission signal, the first robotic arm is controlled to enter the work sub-area to perform the concrete printing task; Once the concrete printing task is completed, the second robotic arm is controlled to return to the interruption point to resume the metal printing task.

[0014] Optionally, the central control system is further configured to perform gantry crane cross-rail transfer control, including: The gantry crane is controlled to pause operation and return to a safe position, then moved to the docking point of the transverse track and engaged with the transverse trolley. Unlock the connection to the current orbit and switch to backup power; The drive traverse trolley moves the gantry frame to the target ground rail, aligns and locks it in place, restores main power and communication, updates coordinate mapping, and continues operation on the new ground rail.

[0015] Optionally, the composite process control module is further configured to perform multi-welding torch collaborative control, including: Set the number of welding guns to be activated according to the required weld width, and select the corresponding number of target welding guns in the corresponding metal printing segment; The digital output port sends a synchronous arc ignition start signal to the welding power supply and wire feeding mechanism corresponding to the selected welding torch, enabling multiple welding torches to weld in parallel. A synchronous arc extinguishing stop signal is issued at the end of the printing segment.

[0016] Compared with existing technologies, the advantages of this application are as follows: By using a central control system to plan and coordinate the composite path of concrete lamination / jetting printing and metal arc additive manufacturing, integrated construction of reinforced concrete composite structures is achieved, avoiding the cumbersome process of prefabricating steel skeletons and then pouring concrete in traditional separate construction. The central control system generates optimized paths based on the temporal and spatial characteristics of the composite process, effectively coordinating the deposition sequence and spatial avoidance of the two materials, ensuring the quality of the interface bonding between metal and concrete, and avoiding thermal damage to uncured concrete from high-temperature metal. The concrete printing module integrates both lamination and jetting processes, adapting to the forming requirements of different structural parts; the metal printing module uses arc additive manufacturing, which has high deposition efficiency. The entire system, with central control as its core, seamlessly integrates the additive manufacturing processes of two dissimilar materials, improving the dimensional flexibility and process integration of composite printing, and meeting the integrated and automated construction needs of large reinforced concrete components such as buildings and bridges. Attached Figure Description

[0017] Figure 1 A schematic diagram of a metal-concrete composite additive manufacturing system; Figure 2 This is a schematic diagram of a combination of a gantry printer and a floor track. Figure 3 This is a schematic diagram of another combination of a gantry printer and a floor rail. Figure 4 A schematic diagram of the overall control architecture for a metal-concrete composite additive manufacturing system; Figure 5 A schematic diagram of the control signal transmission topology for a metal-concrete composite additive manufacturing system; Figure 6 A schematic diagram of the construction process for a metal-concrete composite additive manufacturing system; Figure label: 1-Gantry printer, 2-Metal printing unit, 3-Concrete printing unit, 4-Transport trolley, 10-Central control system, 11-Gantry frame, 111-Ground rail, 115-Transverse rail, 116-Transverse trolley. Detailed Implementation

[0018] The present application will now be described in further detail with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the subject matter of the present application to the following embodiments. All technologies implemented based on the content of the present application fall within the scope of protection of the present application.

[0019] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of the present invention is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0020] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," and "parallel" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, or parallel, but rather that it can be slightly tilted or have a deviation. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical," not that the structure must be completely horizontal, but that it can be slightly tilted. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," or "parallel" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" only distinguish one entity or operation from another, and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] Current technology lacks equipment capable of simultaneously creating composite additive construction from concrete and metal, making efficient synchronization difficult. Furthermore, the printing scale of existing concrete 3D printing equipment is limited by the gantry span. When printing ultra-large-scale components, multiple machines are often required to be spliced ​​in sections, increasing costs and affecting molding quality, thus limiting industrial applications.

[0024] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a metal-concrete composite additive manufacturing system provided in an embodiment of this application. The metal-concrete composite additive manufacturing system may include a concrete printing module 3, a metal printing module 2, and a central control system 10; The concrete printing module 3 is used to perform lamination printing and jet printing of concrete materials, and the metal printing module 2 is used to perform arc additive manufacturing of metal materials. The central control system 10 is used to generate a composite printing path plan and a composite process control strategy that includes a metal printing path and a concrete printing path based on the temporal and spatial characteristics of the composite process. Based on the composite printing path plan, it controls the concrete printing module to print concrete material, controls the metal printing module to perform arc additive manufacturing of metal material, and controls the parameters of the composite process during the composite printing process to complete the integrated construction of the reinforced concrete composite structure.

[0025] Specifically, the central control system 10 is configured to: during the composite printing process, control the metal printing module 2 to melt and deposit metal material layer by layer or segment to form a steel reinforcement skeleton or metal structure layer, and control the concrete printing module 3 to print concrete material inside or outside the already formed steel reinforcement skeleton or metal structure layer, so that metal printing and concrete printing are performed alternately in a preset order.

[0026] Based on this, the gantry printer 1 includes a gantry frame 11 and a ground rail 111; the moving paths of the gantry frame are arranged in parallel; a transverse rail 115 is provided between the moving paths, and a transverse trolley 116 is provided on the transverse rail. The gantry frame can move along the ground rail to the transverse trolley, and the transverse trolley can move along the transverse rail. The transverse trolley is used to move the gantry frame from one set of ground rails to another set of ground rails; the gantry frame is connected to at least one robotic arm, which can move along the gantry frame crossbeam and can selectively install a concrete print head or a metal print head.

[0027] like Figure 1 As shown, the gantry printer 1 includes a gantry frame 11, and the movement paths of all the gantry frames 11 are arranged in parallel.

[0028] The length of the moving path of the gantry frame 11 can be set to be the same or different. Figure 2 Examples include two gantry printers 1 and a case where the lengths of the movement paths of the two gantry printers 1 are the same.

[0029] Figure 3 An example is given of three gantry printers 1, in which two of the gantry printers 1 have the same length of movement path, and the length of the movement path of the third gantry printer 1 is different from the other two.

[0030] The central control system 10 will be explained from the perspective of system architecture and control logic.

[0031] In this embodiment, the central control system 10 can be a computer or a high-performance programmable logic controller (PLC) as the master station. The central control system 10 establishes communication connections with the gantry printer, robotic arm, and other process equipment via industrial Ethernet or fieldbus. Simultaneously, the central control system 10 interacts with the motion control unit of the gantry frame, the drive unit of the robotic arm, the welding power supply, the wire feeding power supply, the wire feeding mechanism, the water cooling device, the pump truck, the nozzle valves, and the material handling equipment via digital input / output interfaces or bus protocols.

[0032] The central control system 10 includes a gantry frame control submodule, a track rotation motion control submodule, a robotic arm motion control submodule, and a composite process control module; The gantry frame control submodule controls the gantry frame's moving speed, position, and acceleration / deceleration curve along the ground rail, and precisely positions the gantry frame at the docking point on the transverse track. The track-turning motion control submodule controls the movement of the transverse trolley along the transverse track, unlocks the gantry frame from the current ground rail, locks it to the transverse trolley, and relocks and updates the coordinate mapping of the gantry frame on the target ground rail. The robotic arm motion control submodule controls the robotic arm's movement path along the gantry frame's crossbeam and the spatial trajectory of the robotic arm's end effector. The composite process control module controls the printing process parameters of the concrete or metal printhead, including extrusion speed, wire feed speed, welding current and voltage, and multi-welding gun coordination.

[0033] The metal printing module includes an arc welding gun, a wire feeding mechanism, a welding power source, a wire feeding power source, a water cooling device, and a protective gas supply device; the concrete printing module includes a concrete pumping system, an extrusion nozzle, and a material mixing device; the central control system is electrically connected to the arc welding gun, the wire feeding mechanism, the welding power source, the wire feeding power source, the water cooling device, the protective gas supply device, the concrete pumping system, the extrusion nozzle, and the material mixing device, respectively, and is used to control the metal printing module to form a steel reinforcement skeleton or a metal structure layer in a preset alternating sequence, and to control the concrete printing module to print concrete material inside or outside the steel reinforcement skeleton or the metal structure layer.

[0034] Metal printing heat source type refers to the spatial distribution of the heat source used to melt the metal wire during metal arc additive manufacturing. Based on the number and arrangement of welding torches on the metal print head, metal printing heat source types include single-point arc heat source type and multi-point arc heat source type. Single-point arc heat source type corresponds to using only one welding torch for the deposition operation, and can be approximated as a single point heat source in space; multi-point arc heat source type corresponds to using multiple welding torches simultaneously for parallel deposition operations, and the continuous arrangement of multiple welding torches can be approximated as a lattice heat source in space.

[0035] To further illustrate the application scenarios of the method provided in this application embodiment, the method provided in this application embodiment can be applied to the central control system 10 of composite additive manufacturing equipment. Please refer to... Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of the overall control architecture of the metal-concrete composite additive manufacturing system provided in the embodiments of this application. Figure 5 A schematic diagram of the control signal transmission topology of the metal-concrete composite additive manufacturing system provided in the embodiments of this application.

[0036] The metal-concrete composite additive manufacturing system can adopt a hierarchical control architecture, consisting of a central control system 10, controllers of various execution devices, and sensing and monitoring devices, which work together to complete the additive printing of both concrete and metal materials.

[0037] The central control system 10 is located in the central monitoring room and includes an embedded industrial PC or industrial PC, a PLC controller (master-slave hot standby), I / O modules, A / D modules, and power conversion modules. The central control system 10 typically uses an industrial PC or high-performance PLC as the master station, responsible for task planning, path generation, and overall scheduling of various devices. The central monitoring room also houses a core server as the core layer device for data storage and processing, and dual-machine equipment for system redundancy and hot standby, ensuring the reliability of the control system. The control cabinet integrates mains power input and a UPS uninterruptible power supply to provide stable power to the entire system.

[0038] Before the printing task begins, the central control system 10 distributes the additive manufacturing program and data to the motion control PLCs and robotic arm controllers of each gantry according to the predetermined division of labor. In this system, the movement paths of all gantry bodies are set in parallel. The central control system 10 first divides the task area and priority of each gantry printer, sets the printing sequence, and then sends motion control commands to the servo control PLCs of each gantry body, distributing the printing program segments to each robotic arm controller. Each control unit then enters the ready state.

[0039] In the execution layer, each gantry printer's gantry frame is equipped with a motion control PLC, responsible for controlling the X-axis and Z-axis positioning and the Y-axis (external slide rail of the robotic arm) movement linked with the robotic arm. Each robotic arm controller (robot control cabinet) is responsible for controlling the movement and process actions of the six-axis robotic arm and the end effector (concrete print head or metal print head). During metal printing, the robotic arm controller sends arc initiation, arc extinguishing, and wire feeding commands to the welding power source and wire feeder; during concrete printing, it sends extrusion and stop commands to the pump truck and nozzle valves. The concrete material supply system (mixing plant, pump truck), mobile material handling equipment (AGV transport trolley), welding power source and wire feeder, transfer platform, and other peripheral equipment each have control modules that communicate with the central control system 10.

[0040] The system interconnects the central control system 10, PLC, and intelligent devices through an industrial communication network, supplemented by digital I / O signals for emergency interlocking and real-time interaction. The central control system 10 issues commands via industrial Ethernet or fieldbus, enabling upper-level monitoring and lower-level real-time control. The servo control PLC communicates with the servo driver via EtherCAT real-time bus to achieve multi-axis linkage. The central control system 10 and lower-level controllers can exchange status and parameters using protocols such as Ethernet / IP and Modbus. Key interlocking signals utilize hard-wired digital I / O or remote I / O modules to ensure millisecond-level response. The gantry crane motion control PLC and the robotic arm controller communicate via digital I / O, sending and receiving preparation and completion signals. The mobile trolley controller communicates with the central control system 10 via a wireless network, receiving scheduling commands and providing position feedback.

[0041] like Figure 5 As shown, the central control system 10 / A sends task paths, start commands, pause commands, and coordination commands to all motion control modules and process control modules via industrial Ethernet. Specifically, the central control system 10 / A establishes communication connections with the motion control PLC B1 of the first gantry crane, the motion control PLC B2 of the second gantry crane, the motion control PLC B3 of the third gantry crane, the first concrete robotic arm controller C1, the second concrete robotic arm controller C2, the material supply system F, the material handling system G, the transfer platform control system H, and the welding process system I.

[0042] Each gantry crane's motion control PLC communicates with the metal robotic arm controller mounted on that gantry crane via a bus: Gantry crane motion control PLC B1 interacts with the first metal robotic arm controller D1 via the bus; Gantry crane motion control PLC B2 interacts with the second metal robotic arm controller D2 via the bus. The motion control PLC sends a positioning completion signal to the metal robotic arm controller and receives a printing completion feedback signal.

[0043] The central control system 10 / A schedules the track control system of C1 / C2 or D1 / D2 and their corresponding gantry frame according to the task allocation in the composite printing path planning, so that the corresponding robotic arm can move along the gantry frame and perform printing.

[0044] The concrete robotic arm and the metal robotic arm achieve master-slave collaborative control through discrete digital I / O signals: the controllers of the two are connected via hardwiring to transmit intrusion request signals, intrusion permission signals, and reset signals, avoiding interference in the shared space. When the central control system I / O determines that the concrete robotic arm is about to enter the working area of ​​the metal robotic arm, it triggers an interruption and recovery process through the aforementioned I / O signal link.

[0045] The transfer platform control system H is controlled by the central control system 10 / A and is responsible for coordinating the movement of the gantry crane from one set of ground rails to another. H establishes track switching signal interaction with the motion control PLCs B1, B2, and B3 of gantry cranes No. 1, 2, and 3, respectively, and sends start / complete signals before and after track switching to realize the movement of the gantry crane from the current track to another set of parallel tracks.

[0046] The material supply system F receives concrete pump start and stop commands from the central control system 10 / A, controls the material discharge from the mixing plant and the pump truck pumping, and returns the pumping status signal to the central control system 10 / A in real time, keeping it synchronized with the concrete robotic arm printing status. The welding process system I receives arc ignition, arc extinguishing, and wire feeding commands from the first metal robotic arm controller D1 or the second metal robotic arm controller D2, and simultaneously transmits the welding power supply operating status (arc voltage, current feedback) back to the central control system 10 / A or the corresponding metal robotic arm controller in real time. The sensor and quality monitoring system J transmits the collected sensor information, such as the molten pool status, the cross-sectional dimensions of the concrete printing strip, and the remaining material in the hopper, to the central control system 10 / A in real time via industrial Ethernet or analog interface, or to the corresponding C1, C2, D1, and D2, for closed-loop adjustment of motion speed, material extrusion rate, and welding heat input.

[0047] Optionally, the central control system 10 can be specifically configured as follows: When generating the composite printing path plan, the 3D printing model is decomposed into a metal printing segment sequence and a concrete printing segment sequence according to the material type. The metal printing segment sequence contains multiple consecutive metal printing segments, each corresponding to a continuous path that needs to be performed by the metal print head for arc additive welding. The concrete printing segment sequence contains multiple consecutive concrete printing segments, each corresponding to a continuous path that needs to be performed by the concrete print head for extrusion deposition. For each planned metal printing segment, a heat-affected zone (HAZ) is generated by offsetting the minimum safe space distance outward from the geometric contour of that metal printing segment. This HAZ ensures that the spatial paths of subsequently planned concrete printing segments completely avoid the HAZ. For each metal printing segment in the sequence, the central control system 10 uses the geometric contour of that segment as a reference and offsets it outward by a pre-calculated minimum safe space distance to generate a HAZ surrounding that segment. This HAZ represents the spatial area where concrete material cannot enter during the metal printing process. When planning subsequent concrete printing segments, the central control system 10 ensures that the spatial path of each concrete printing segment completely avoids all generated HAZs, thereby guaranteeing that the real-time spatial distance between the concrete print head and the metal printing heat source is always no less than the minimum safe space distance, preventing thermal damage to the concrete material due to excessive proximity in the spatial dimension.

[0048] For each planned concrete printing segment, the central control system 10 identifies the most recent end time of metal heat exposure for each spatial location within that segment and inserts a forced waiting time. The length of this forced waiting time is not less than the minimum safety time interval, and the starting point for the forced waiting time is the most recent end time of metal heat exposure. For each concrete printing segment in the sequence, the central control system 10 identifies the most recent end time of metal heat exposure for each spatial location within that segment. The end time of metal heat exposure refers to the last time that spatial location was affected by the heat radiation from the metal printing heat source, such as the moment the metal printhead completes the melting of the area adjacent to that location and removes it, or the moment the metal printhead extinguishes its arc and withdraws from the vicinity of that location. The central control system 10 inserts a forced waiting time for that concrete printing segment. The length of this forced waiting time is not less than the pre-calculated minimum safety time interval, and the starting point for the forced waiting time is set to the aforementioned most recent end time of metal heat exposure. By inserting a forced waiting time, the central control system 10 ensures that when the concrete print head moves to the spatial position, the temperature accumulated at that position due to historical metal heat sources has been reduced to below the maximum temperature threshold of the concrete material through natural cooling, thereby ensuring the safety of concrete printing in the time dimension.

[0049] Optionally, the composite process control module can also be configured to perform multi-welding gun collaborative control: The number of welding torches to be used is determined based on the dimensions of the printed structural components and the distribution of the reinforcing bars. A corresponding number of target welding torches are selected in the corresponding metal printing segment. A synchronous arc ignition start signal is sent to the welding power supply and wire feeding mechanism corresponding to the selected welding torches through the digital output port, so that multiple welding torches can be welded in parallel. A synchronous arc extinguishing stop signal is sent at the end of the printing segment.

[0050] The central control system 10 allows for group control and dynamic switching of multiple welding torches. Specifically, control commands can be inserted into the program to select and enable one or more welding torches to work simultaneously. These operations are achieved by the robotic arm controller outputting control signals to the power supply or wire feeding channel of each welding torch: each welding torch has a start / stop input signal on its control interface. The robotic arm program pulls up the "enable" signal line of the corresponding welding torch as needed, thereby turning on the current output and wire feeding of that welding torch; when it needs to be turned off, the signal is pulled down.

[0051] When generating the composite printing path plan, the central control system 10 automatically sets the number of welding guns to be activated based on the required deposition width of the current metal printing segment, and embeds this number of welding guns as a process parameter into the corresponding metal printing segment path code. To facilitate operator configuration, the central control system 10 provides a welding gun group configuration function in the human-machine interface. Operators can pre-classify multiple corresponding welding guns into a group for parallel deposition, and can call different welding gun group numbers in the path program of different printing layers or different printing segments.

[0052] When the metal robotic arm reaches a metal printing segment containing parameters for the number of welding torches activated, the metal additive manufacturing subsystem reads these parameters and selects the corresponding number of target welding torches from multiple torches at the end of the robotic arm. Unselected torches remain off. The subsystem sends a synchronous arc-start signal via a digital output port to the independent welding power supply, hot wire power supply, and wire feeding mechanism corresponding to each selected torch, ensuring synchronized arc ignition and wire feeding. When multiple torches are working simultaneously, the subsystem monitors the current and voltage of each torch, ensuring the total current does not exceed the upper limit and using load balancing to ensure the arcs of multiple torches work together to form a uniform and controllable molten pool. At the end of the metal printing segment, the subsystem sends a synchronous arc-extinguishing stop signal to the power supply and wire feeding mechanism of all selected torches, causing the arcs to extinguish synchronously and wire feeding to stop. Through this control, the number of welding torches involved in the operation can be flexibly adjusted according to process requirements, the weld width can be dynamically adjusted, and forming efficiency and cross-sectional dimension adjustability can be improved.

[0053] Optionally, the central control system 10 is further configured to perform master-slave cooperative control, including: When the first gantry crane needs to enter the current working area of ​​the second gantry crane, the central control system issues a clearance command to the second gantry crane, controlling the second gantry crane to move along the ground rail to a preset waiting position; the central control system receives the ready signal from the second gantry crane, and after confirming that the working area is cleared, issues an entry permission signal to the first gantry crane, controlling the first gantry crane to enter the working area.

[0054] After the first gantry frame enters the work area, when the first robotic arm driving the concrete print head is about to enter the work sub-area of ​​the second robotic arm driving the metal print head and the spatial distance is less than the minimum safe space distance, an intrusion request signal is sent to the second robotic arm; before receiving the intrusion permission signal issued by the second robotic arm in response to the intrusion request signal, the second robotic arm is controlled to interrupt the current metal printing task and retreat to a safe waiting position; after receiving the intrusion permission signal, the first robotic arm is controlled to enter the work sub-area to perform the concrete printing task; after the concrete printing task is completed, the second robotic arm is controlled to return to the interruption point to resume the metal printing task.

[0055] In the composite additive manufacturing process, the central control system 10 adopts a two-level collaborative avoidance strategy to handle the area occupancy conflict between gantry frames and the work area interference problem between the metal robotic arm and the concrete robotic arm on the gantry frame.

[0056] When the first gantry crane needs to enter the current working area of ​​the second gantry crane for a task, the central control system 10 first determines whether the second gantry crane is currently performing a printing task. If the second gantry crane occupies the area, the central control system 10 sends a avoidance command to the motion control PLC of the second gantry crane. This command includes the target waiting position (usually a safe stopping point at one end of the ground rail). After receiving the command, the second gantry crane moves along the ground rail at a set speed to the waiting position. After its X-axis drive system completes positioning, it sends a "ready in position" signal back to the central control system 10 via the servo driver. After confirming that the working area is completely cleared, the central control system 10 sends an entry permission signal to the first gantry crane. The first gantry crane then moves to the designated working area and begins performing its printing task. This level of avoidance ensures that there will be no physical collisions between the gantry cranes and provides macroscopic space protection for precise avoidance at the robotic arm level. After the first gantry frame enters the work area, the robotic arms mounted on the two sets of gantry frames (including the first robotic arm driving the concrete print head and the second robotic arm driving the metal print head) may need to work alternately in a small shared space. When the first robotic arm (concrete main unit) is about to enter the work sub-area of ​​the second robotic arm (metal slave unit), and the spatial distance between the two is less than the preset minimum safe space distance, the central control system 10 initiates the intrusion avoidance process at the robotic arm level.

[0057] Specifically, the first robotic arm controller identifies potential conflict risks in advance based on the "intrusion point" markers in the pre-programmed path. The controller sends an "intrusion request" signal to the second robotic arm controller via its digital output port. Upon sending the request, the first robotic arm immediately executes a waiting instruction and suspends its movement. Upon receiving the request signal, the second robotic arm controller triggers an interruption avoidance subroutine: first, it locks the robotic arm's movement via the emergency stop interface, and simultaneously sends arc-extinguishing and wire-stopping signals to the welding power supply, hot wire power supply, and wire feeding mechanism to ensure the safe shutdown of the metal print head; then, it controls the second robotic arm to quickly move along the preset evacuation path to a safe waiting position. Once in position, the second robotic arm's controller sends an "intrusion permission" signal to the first robotic arm via its digital output. Upon receiving this signal, the first robotic arm releases its waiting state, resumes movement, and enters the original working sub-area of ​​the second robotic arm, executing the concrete printing task according to the composite path plan. During this period, the second robotic arm remains in the safe waiting position, and the welding power supply is in standby mode.

[0058] After the first robotic arm completes the concrete printing task in its designated area and fully exits the work sub-area, its controller sends a "reset" signal to the second robotic arm controller. The second robotic arm controller then executes the recovery procedure: driving the robotic arm back along the recorded original path to the interruption point, while simultaneously sending pre-start commands (e.g., early wire feeding, low-current preheating) to the welding power source, hot wire power source, and wire feeding mechanism to quickly restore the molten pool state to its pre-interruption level. Once everything is ready, the second robotic arm continues the remaining metal printing task from the interruption point.

[0059] Through the above two-level avoidance and master-slave collaborative control, the central control system 10 achieves on-demand interruption and seamless recovery of metal printing tasks while ensuring the continuity of concrete printing and the quality of molding, thereby completing the safe and efficient collaboration of multiple devices and multiple robotic arms in metal-concrete composite additive manufacturing.

[0060] Alternatively, the central control system 10 can also be configured as follows: The gantry crane is controlled to pause operation and return to a safe position, then moved to the docking point of the transverse track and engaged with the transverse trolley. Unlock the connection to the current orbit and switch to backup power; The drive traverse trolley moves the gantry frame to the target ground rail, aligns and locks it, restores main power and communication, updates coordinate mapping, and continues operation on the new ground rail.

[0061] When a gantry crane needs to be switched from its current ground rail to a target ground rail, the central control system 10 first sends a pause command to the motion control PLC of the gantry crane, causing it to stop moving after completing the current printing segment. Simultaneously, all robotic arms on the gantry crane automatically reset to a safe posture (e.g., joints retract to a predetermined angle, printhead raised to a safe height) to prevent collisions during the rail change. Subsequently, the central control system 10 instructs the gantry crane to move along the current ground rail to the preset transverse rail docking point, aligning and engaging the rollers at the bottom of the gantry crane with the support rail on the transverse trolley. Once engaged, the system locks the gantry crane and the transverse trolley together via pins and pin holes in the docking assembly.

[0062] After locking is complete, the central control system 10 controls the gantry crane to unlock its connection with the current ground rail (e.g., releasing the braking mechanism on the ground rail) and switches the gantry crane's drive power to a backup power source (such as the power system built into the traverse trolley or temporary power supply via a cable chain) to ensure that the gantry crane's control system remains online when disconnected from the main ground rail power supply area. Next, the central control system 10 drives the traverse trolley along the traverse track, smoothly transporting the gantry crane to the target ground rail location. Upon reaching the target ground rail, the traverse trolley uses a transmitter and receiver for precise positioning, aligning the support rail with the target ground rail, controlling the joint gap to approximately 2mm. After alignment, the pin extends into the pin hole seat on the target ground rail side, completing the locking of the support rail and the target ground rail.

[0063] After the central control system 10 confirms a secure docking, it instructs the gantry crane to move from the traverse trolley's support rail to the target ground rail, restores main power supply, and disconnects the backup power supply. Simultaneously, the system re-establishes the communication link between the gantry crane's motion control PLC and the central control system, and updates the gantry crane's coordinate mapping relationship based on the new ground rail's coordinate system origin to ensure the accuracy of the subsequent printing path. Finally, the central control system 10 issues a continue operation command to the gantry crane, and the robotic arm returns from its safe posture to its working posture, continuing the printing task on the new ground rail for the unfinished portion of the original composite path plan.

[0064] During the concrete printing process, sensors installed near the print head (such as linear array cameras or laser displacement sensors) collect real-time data on the cross-sectional dimensions of the printed strip and upload it to the central control system 10. The central control system 10 compares the measured dimensions with a preset target range: if the dimension exceeds the upper limit, it increases the movement speed of the robotic arm driving the concrete print head or decreases the pump truck's feeding speed to reduce the extrusion volume; if the dimension is below the lower limit, it decreases the movement speed of the robotic arm driving the concrete print head or increases the pump truck's feeding speed to increase the extrusion volume. Through this closed-loop regulation of speed and flow rate, the actual size of the concrete strip is always maintained within the target range, ensuring that the concrete layers printed by different printing devices have consistent forming quality.

[0065] During the printing process, a residual material sensor (such as a weight sensor or ultrasonic level gauge) installed in the pump truck hopper monitors the amount of remaining concrete material in the hopper in real time and sends the collected material quantity signal to the central control system 10. The pump truck supplies concrete material to the concrete print head, which is driven by a robotic arm mounted on the crossbeam of the gantry printer. The central control system 10 compares the received material quantity signal with preset lower and upper threshold values. When the material quantity signal is lower than the preset lower threshold value, it indicates that the concrete in the hopper is about to run out and continuous printing cannot be maintained. At this time, the central control system 10 sends a material preparation command to the mixing plant control module to start the mixing and preparation of the next batch of concrete; at the same time, the central control system 10 sends a dispatch command to the material transport trolley, notifying the trolley to transport a new hopper pre-loaded with concrete material to the pump truck for docking and unloading. When the material quantity signal is higher than the preset upper threshold value, it indicates that there may be too much concrete in the hopper, posing a risk of blockage or overflow. The central control system 10 triggers an alarm signal and prompts the operator on the operation interface to check the pump truck's feeding status. Through the aforementioned monitoring and automatic scheduling of residual materials, the central control system 10 ensures the continuous supply and safe operation of concrete materials during the concrete printing task performed by the gantry printer.

[0066] The central control system 10 can calculate the minimum safe space distance that satisfies the maximum temperature threshold of concrete materials by establishing a temperature field spatial distribution model, thereby generating a composite printing path plan that includes both metal printing paths and concrete printing paths. This plan can be configured as follows: A corresponding temperature field spatial distribution model is established based on the metal printing heat source type of the metal printhead, and the minimum safe space distance that satisfies the highest temperature threshold of concrete material is calculated based on the temperature field spatial distribution model. A spatiotemporal evolution model of the temperature field is established based on the spatial distribution model of the temperature field, and the minimum safe time interval that satisfies the highest temperature threshold of the concrete material is calculated based on the spatiotemporal evolution model of the temperature field. Based on the minimum safe space distance and the minimum safe time interval, a composite printing path plan for metal printing path and concrete printing path in terms of time and space is generated; the composite printing path plan includes the alternation order of metal printing task and concrete printing task, spatial avoidance distance and interlayer cooling waiting time. The composite printing path plan is sent to the corresponding robotic arms in the gantry printer and the mobile printer, so that the robotic arms can perform arc additive welding of metal materials or printing deposition of concrete materials according to the composite printing path plan.

[0067] The maximum temperature threshold of concrete refers to the limit temperature at which concrete does not suffer thermal damage, loss of mechanical properties, or loss of interfacial bonding strength when heated. In metal-concrete composite additive manufacturing, the high temperature generated by metal arc printing necessitates a pre-set upper limit for the maximum temperature that the concrete material can withstand to prevent burns to adjacent or underlying printed concrete layers. The minimum safe space distance refers to the minimum radial distance that must be maintained between the concrete printing location and the metal printing heat source that is currently operating or has just stopped operating. The central control system 10 substitutes the maximum temperature threshold of the concrete material into the temperature variables in the temperature field spatial distribution model and obtains the minimum safe space distance by inversely solving the distance parameters. At this distance, the temperature at the concrete printing location will not exceed the maximum temperature threshold of the concrete material, thus ensuring that the concrete material does not suffer thermal damage due to excessive spatial proximity.

[0068] Based on the established spatial distribution model of the temperature field, the central control system 10 can further introduce a time variable to establish a spatiotemporal evolution model of the temperature field. This spatiotemporal evolution model is a dynamic physical model describing the simultaneous changes in the temperature field caused by the heat source of metal printing with both spatial distance and time. Because the metal printhead alternately starts and stops during the composite printing process, and because the robotic arm mounted on the gantry printer or mobile printer carries the metal printhead, the state of the heat source is constantly changing, and the surrounding temperature field is always in a non-steady-state transient process. The spatiotemporal evolution model of the temperature field can describe the temperature distribution changes under the combined effects of the duration from the start or cessation of heating by the heat source and spatial distance.

[0069] To more accurately describe temperature decay and environmental cooling effects over long distances, the central control system 10 also introduces an environmental heat loss factor to mathematically express temperature decay over long distances and environmental cooling effects such as air convection and radiation, resulting in a corrected spatiotemporal evolution model of the temperature field. For single-point arc cases, the corrected model is a point heat source temperature field spatiotemporal evolution model; for multi-point arc cases, the corrected model is a line heat source temperature field spatiotemporal evolution model. The central control system 10 substitutes the maximum temperature threshold of the concrete material into the temperature variable in the corrected model and uses the preset spatial distance as a known parameter, obtaining the minimum safe time interval by inversely solving the time variable. The minimum safe time interval refers to the shortest time required for the temperature at a certain spatial location to drop below the maximum temperature threshold of the concrete material due to heat conduction and convection cooling after the metal printing heat source stops working or moves away. This time interval is used to ensure that when the robotic arm carries the concrete printing head to a predetermined position, the temperature accumulated at that position due to historical metal heat sources has already dropped to a safe range through natural cooling.

[0070] The central control system 10 generates a composite printing path planning and composite process control strategy for metal printing paths and concrete printing paths in terms of timing and space, based on the minimum safe space distance and minimum safe time interval. Composite printing path planning is a comprehensive set of control instructions integrating the metal printing task sequence, the concrete printing task sequence, the alternation order and rhythm of the two printing tasks in the time dimension, the avoidance distance constraint in the spatial dimension, and the interlayer cooling waiting time. Specifically, the alternation order of metal printing tasks and concrete printing tasks determines the sequential relationship between the printing actions of the two materials; the spatial avoidance distance ensures that the concrete printing path and the metal printing path maintain a geometric interval of not less than the minimum safe space distance; and the interlayer cooling waiting time ensures that when switching materials, the printed material has sufficient time to cool to below a safe temperature.

[0071] The central control system 10 distributes the generated composite printing path plan and composite process control strategy to the corresponding gantry printer, robotic arm, and other process equipment. The robotic arm carrying the metal printhead receives path instructions and process parameters related to metal printing and executes arc additive manufacturing according to the planned arc initiation position, arc extinguishing position, movement speed, and spatial avoidance constraints. The robotic arm carrying the concrete printhead receives path instructions related to concrete printing and executes concrete lamination or jet printing. Other process equipment receives process control parameters related to composite printing and executes composite additive manufacturing according to the planned extrusion start point, movement trajectory, and composite process strategy.

[0072] In some embodiments, when the heat source for metal printing is a single-point electric arc, it can be considered an ideal point heat source, with heat radiating uniformly in all directions. The temperature distribution typically follows an inverse square law from the heat source to the target point. In this case, it is assumed that the power of the point heat source is Q and the thermal conductivity of air is... According to Fourier's law of heat conduction, the spatial distribution model of the temperature field of a point heat source can be obtained as follows:

[0073] in, Let r be the temperature field and r be the radial distance. This is determined by the highest temperature threshold of the printed material. Substituting the spatial distribution model of the temperature field of the point heat source, the minimum safe space distance is obtained by inverse solution. .

[0074] In other embodiments, when the heat source for metal printing is a multi-point electric arc, it can be considered an ideal linear heat source. In this case, the temperature field distribution typically follows a logarithmic law of distance. Assuming the heat source is distributed along a line segment and the heat at each point is equal, the temperature field change typically exhibits a logarithmic decreasing relationship. Therefore, the spatial distribution model of the linear heat source temperature field can be determined as follows:

[0075] in, For temperature field, For heat source power, Let be the thermal conductivity and r be the radial distance. The spatial distribution model of the temperature field of a line heat source assumes that the propagation of heat along the line segment is superimposed. Therefore, the rate of temperature decrease is slower (logarithmic decrease) the farther away from the heat source.

[0076] For point or line heat sources, temperature changes over time involve processes of heat conduction and heat accumulation. When considering indoor spaces, temperature changes over time are influenced by multiple factors, including the continuous operation of the heat source, airflow (convection), and spatial geometry. Based on these factors, the temperature change process typically exhibits certain dynamic characteristics, and this change can be approximated by establishing a spatiotemporal evolution model of the temperature field.

[0077] For a point heat source or a line heat source, temperature changes mainly depend on the continuous input of heat from the heat source, the heat conduction and diffusion processes, and the heat accumulation in space. According to the principle of heat conduction, changes in the temperature field are not only determined by the presence of the heat source, but also by time, especially under unsteady (transient) conditions.

[0078] Imagine a continuously operating heat source within a confined space. Air continuously absorbs heat and diffuses it through conduction. Over time, the temperature gradually rises until an equilibrium state is reached, and the temperature gradient stabilizes. Therefore, in the actual process of metal-concrete composite additive manufacturing, the alternating start and stop of the printhead causes the heat source's state (on, moving, off) to constantly change, and the surrounding temperature field is always in a dynamic process, rarely reaching an ideal steady state. To accurately control the concrete from thermal damage during alternating printing, this dynamic and unsteady temperature evolution process must be quantitatively described and predicted.

[0079] Transient heat conduction refers to the diffusion of heat through a medium over time until the system reaches thermal equilibrium. The fundamental equation for heat conduction is the heat conduction equation (heat diffusion equation), which describes temperature changes in time and space:

[0080] It is a spatial location. and time The temperature below, For thermal diffusivity, Defined as ,in, Thermal conductivity, For density, Specific heat capacity. The Laplace operator for temperature describes the diffusion of temperature in the air. In this equation, heat diffuses from high-temperature regions to low-temperature regions, and the temperature field gradually changes over time until a steady state is reached. However, when the distance range extends from 10 mm to 1000 mm, the original point heat source model may no longer be applicable, especially considering that temperature changes are affected by various factors, including cooling effects, radiation losses, and the complexity of heat diffusion. Therefore, this application modifies the temperature field model to better describe the temperature distribution over long distances.

[0081] Optionally, the methods for modifying the temperature field model include: A corresponding spatiotemporal evolution model of the point heat source temperature field is established based on the spatial distribution model of the point heat source temperature field. The spatiotemporal evolution model of the point heat source temperature field is modified based on the temperature decay over long distances and the environmental cooling effect to obtain a modified spatiotemporal evolution model of the point heat source temperature field. The minimum safe time interval that satisfies the highest temperature threshold of the printing material is calculated based on the modified spatiotemporal evolution model of the point heat source temperature field.

[0082] Alternatively, a corresponding spatiotemporal evolution model of the temperature field of the linear heat source can be established based on the spatial distribution model of the temperature field of the linear heat source; the spatiotemporal evolution model of the temperature field of the linear heat source can be modified based on the temperature decay over long distances and the environmental cooling effect to obtain a modified spatiotemporal evolution model of the temperature field of the linear heat source; and the minimum safe time interval that satisfies the highest temperature threshold of the printing material can be calculated based on the modified spatiotemporal evolution model of the temperature field of the linear heat source.

[0083] In regions far from the heat source, heat is lost not only through conduction but also through convection and radiation. In this application, due to the need for accurate modeling of temperature changes over long distances, an attenuation factor is introduced into the spatial distribution model of the heat source temperature field. Adjustments can be made through environmental factors (such as airflow and radiative heat transfer). A larger value indicates a faster temperature decay. A smaller value indicates a slower temperature decay.

[0084] In the case of point and line heat sources, power is the primary factor affecting temperature. With increasing distance, although the power of the heat source remains constant, the temperature field gradually expands and decays through heat diffusion and radiation. Temperatures in distant regions will be more significantly affected by ambient cooling. For very long distances, convection cooling terms or ambient temperature correction terms may be added. Depending on the specific application scenario, the modeling of cooling effects can be further refined.

[0085] In summary, by modifying the spatial distribution model of the point heat source temperature field through long-distance temperature attenuation and environmental cooling effects, the resulting spatiotemporal evolution modified model of the point heat source temperature field is as follows:

[0086] in, For temperature field, For heat source power, Thermal conductivity, Radial distance, For thermal diffusivity, The duration of heating, measured from the moment the heat source begins to generate heat or ceases to generate heat. Environmental heat loss factor The modified model of the spatial distribution of the temperature field of the line heat source is obtained by correcting the spatiotemporal evolution model of the temperature field of the line heat source as follows:

[0087] in, For temperature field, For heat source power, Thermal conductivity, Radial distance, For thermal diffusivity, The duration of heating, measured from the moment the heat source begins to generate heat or ceases to generate heat. This is the environmental heat loss factor, also known as the attenuation factor.

[0088] In practical applications, temperatures at different distances can be measured experimentally to further validate and adjust the model. Experimental data can then be used to accurately determine... By using parameters such as airflow and humidity, a modified model of the spatiotemporal evolution of the heat source temperature field is obtained. This model can be further modified based on actual environmental factors such as airflow and humidity. For example, in air, the effects of thermal radiation and convection may differ, especially when the distance is greater than 100 mm, where cooling may become the dominant factor.

[0089] For distances ranging from 10mm to 1000mm, the temperature distribution models for point and line heat sources need to be corrected by introducing an additional attenuation factor to account for temperature decay over long distances and environmental cooling effects. This embodiment of the application introduces an additional attenuation factor into the existing heat conduction model. This parameter can better describe temperature changes over long distances. Through further experiments and measurements, model parameters can be adjusted to obtain more accurate temperature predictions.

[0090] Before printing the equipment, temperature gradient data can be measured. By using the measured data, the key parameters in the formula can be further confirmed, and then the key thresholds in the key timing and spatial control logic of composite additive manufacturing can be determined.

[0091] Finally, the highest temperature threshold of the printing material is substituted into the above-mentioned temperature field spatial distribution model and heat source temperature field spatiotemporal evolution correction model to calculate the minimum safe space distance and minimum safe time interval. Based on the minimum safe space distance and minimum safe time interval, the composite additive timing and spatial printing path of the printing material and the composite process control strategy are determined. Based on the composite additive timing and spatial printing path, the printing equipment is controlled to perform printing work, realizing dual core control of timing and space.

[0092] The following is a schematic diagram illustrating the construction process of a metal-concrete composite additive manufacturing system. Please refer to... Figure 6 , Figure 6 A schematic diagram of the construction process of the metal-concrete composite additive manufacturing system provided in the embodiments of this application.

[0093] During the print preparation phase, the operator logs in through the human-machine interface of the central control system 10 and imports the print model exported from third-party software into the central control system 10. The central control system 10 automatically partitions the print model into structural zones, dividing it into metal print areas and concrete print areas. Based on preset layer thickness and path rules, the central control system 10 performs model positioning, trajectory slicing, path planning, and process control strategies for the metal and concrete print areas, generating initial metal and concrete print trajectories. Subsequently, the central control system 10 executes print simulation and spatial and process interference checks to verify whether there is spatial overlap or process conflict between the metal and concrete print paths. If the interference check passes, the central control system 10 generates the final print program and the corresponding list of printing materials.

[0094] Based on this, the central control system 10 acquires the type of metal printing heat source of the metal printhead. The metal printing heat source types include single-point arc heat source types and multi-point arc heat source types. The central control system 10 establishes a corresponding temperature field spatial distribution model based on the acquired metal printing heat source type: when the metal printing heat source is a single-point arc, the central control system 10 establishes a point heat source temperature field spatial distribution model; when the metal printing heat source is a multi-point arc, the central control system 10 establishes a line heat source temperature field spatial distribution model. Based on the temperature field spatial distribution model, the central control system 10 calculates the minimum safe space distance to satisfy the highest temperature threshold of the concrete material, that is, the minimum radial distance that needs to be maintained between the concrete printing position and the metal printing heat source.

[0095] By further introducing a time variable into the spatial distribution model of the temperature field, a spatiotemporal evolution model of the temperature field is established. This model is then modified based on long-distance temperature decay and environmental cooling effects, resulting in a modified spatiotemporal evolution model of the temperature field. The central control system 10 substitutes the highest temperature threshold of the concrete material into the modified model and solves the time parameters to obtain the minimum safe time interval, i.e., the shortest time required for the concrete material to cool below a safe temperature after the metal printing heat source stops operating. Based on the minimum safe spatial distance and the minimum safe time interval, the central control system 10 generates a composite printing path plan and process control strategy for the metal printing path and the concrete printing path in terms of time and space. The composite printing path plan integrates the alternation sequence of the metal printing task and the concrete printing task, the spatial avoidance distance, the interlayer cooling waiting time, and the composite process parameters.

[0096] The central control system 10 sends the generated composite printing path plan to the corresponding robotic arms in the gantry printer and the mobile printer, and initiates the printing task. In the metal printing channel, the central control system 10 controls the welding power source corresponding to the metal print head to ignite the arc, the wire feeding mechanism to feed the wire, and the protective gas to operate. The robotic arm performs arc additive welding of the metal material according to the composite printing path plan, completing the forming of the metal reinforcement structure or embedded functional parts. In the concrete printing channel, the central control system 10 first controls the mixing equipment to meter, load, mix, and discharge the material. After integrated mixing, the concrete is received by the receiving device. The central control system 10 sends a scheduling command to the material transport trolley, which transports the hopper containing the concrete material to the pump truck position. Then, it controls the gas valve to open and the pumping equipment to operate. The concrete is deposited by the robotic arm through the nozzle installed at the end of the concrete robotic arm according to the planned three-dimensional path. During the printing process, the central control system 10 monitors the working status of the robotic arm in real time and adjusts the movement speed of the pumping equipment and the robotic arm based on sensor feedback.

[0097] Once all printing tasks are completed, the central control system 10 sequentially sends termination commands to each executing device, shutting down the welding power supply, pump truck, nozzle valves, and all servo axis devices, and controlling all robotic arms and gantry frames to return to safe positions. The central control system 10 then activates the cleaning equipment to perform high-pressure water cleaning or airflow backflushing on the pumping pipes, nozzles, arc welding heads, and wire feeding mechanisms to remove residual material. Finally, the central control system 10 automatically summarizes the process data, sensor records, and control logs generated throughout the printing process to form a construction data report for subsequent process evaluation and quality traceability. The entire construction process achieves fully automated closed-loop control, from third-party software modeling to central control system 10 scheduling, from parallel printing of metal and concrete in dual channels to post-processing cleaning.

[0098] In some embodiments, when multiple gantry cranes need to be concentrated on the same set of ground rails for joint printing (to increase the printing range or for collaborative operation), the control logic of the central control system 10 is as follows: The central control system 10 first calculates the required number of gantry frames and their arrangement order on the ground rails based on the printing task requirements. Then, it sequentially performs cross-rail transfer operations on each gantry frame 11, converging them onto the target ground rail 111. During the printing process, the robotic arm on each gantry frame monitors the distance between adjacent gantry frames in real time through a collision detection module. The central control system 10 sets a minimum safe distance threshold. Once the actual distance between adjacent gantry frames falls below this threshold, the slave gantry frames automatically decelerate or stop moving to prevent collisions. The central control system 10 supports two collaborative printing modes: In the zoned operation mode, the central control system 10 divides the total length of the ground track into multiple sections, with each gantry 11 responsible for one section. The central control system 10 dynamically allocates the boundary coordinates between each section to prevent interference between adjacent robotic arms. In the synchronous composite printing mode, for example, one gantry 11 has a concrete print head installed at the end of its robotic arm, while another has a metal print head. The central control system 10 schedules the printing according to the layered path of the same workpiece using a master-slave synchronous strategy. The master gantry sends a position trigger signal, and the slave gantry follows the master gantry after a fixed delay, achieving alternating or synchronous composite printing of concrete and metal. The robotic arms of each gantry independently execute local path planning, but exchange end-effector pose data with each other in real time to avoid spatial interference.

[0099] The following description will focus on the physical structure of the metal-concrete composite additive manufacturing system provided in this application. A transverse track 115 is provided between the gantry printers 1, and a transverse trolley 116 is mounted on the transverse track 115. The gantry frame 11 can move along the ground rails onto the transverse trolley 116, which moves along the transverse track 115 to move the gantry frame 11 from one set of ground rails to another. In this embodiment, the transverse track 115 is perpendicular to the ground rails. In an optional embodiment, such as... Figure 1 As shown, the transverse track 115 includes a track plate and a geared rail, and the transverse trolley 116 includes a frame, gears and wheels. The wheels move along the track plate, the gears mesh with the geared rails, and the motor drives the gears to make the transverse trolley 116 move along the transverse track 115.

[0100] The following focuses on the specific implementation method of changing the track of the gantry frame 11 via the transverse trolley 116 and the transverse track 115.

[0101] In one alternative implementation, such as Figure 1 As shown, all gantry frames have a transverse track 115 at one end of the ground rail. The transverse trolley has a load-bearing rail with the same span and elevation as the ground rail. The load-bearing rail and the ground rail are aligned via a docking assembly. The joint gap is approximately 2mm, ensuring the rollers can pass through while avoiding interference. The docking assembly includes a transmitter, receiver, pin, and pin hole seat: the transmitter and receiver are respectively located at the docking ends of the load-bearing rail and the ground rail, with the receiver receiving the transmitter's beam; the pin and pin hole seat are connected to both ends, and after alignment, the pin extends into the pin hole seat for a secure docking. The docking assembly is electrically connected to the first electrical control box.

[0102] When the gantry crane needs to switch from the first set of ground rails to the second set of ground rails, the first electrical control box controls the transverse trolley to move along the transverse track, and the support rail approaches the first set of ground rails; after the receiver receives the transmitter signal, the pin extends into the pin hole seat to complete the docking; the gantry crane moves along the ground rail to the support rail (i.e., the transverse trolley supports the gantry crane); then the pin is released and unlocked; the transverse trolley continues to move to the second set of ground rails, repeats the alignment and pin locking; finally, the gantry crane moves from the support rail to the second set of ground rails, completing the rail change.

[0103] The printing equipment for metal-concrete composite additive manufacturing described in this embodiment enables large-scale 3D printing by setting up a gantry printer 1 along its moving path. Several gantry printers can either move to the same set of ground rails for collaborative printing via the transverse rails 115 and transverse trolleys 116, or they can be divided into smaller units for independent printing. The end effector of the robotic arm can connect to either a concrete print head or a metal print head, integrating different concrete-metal printing processes into the same equipment for composite additive manufacturing. The gantry frame provides a wide range of movement, while the robotic arm provides precise, small-range control, thereby achieving high-precision composite additive manufacturing.

[0104] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A metal-concrete composite additive manufacturing system, characterized in that, Includes concrete printing module, metal printing module and central control system; The concrete printing module is used to perform lamination printing and jet printing of concrete materials, and the metal printing module is used to perform arc additive manufacturing of metal materials. The central control system is used to generate composite printing path planning and composite process control strategy, which includes metal printing path and concrete printing path, based on the temporal and spatial characteristics of the composite process. Based on the composite printing path planning, the system controls the concrete printing module to print concrete material, controls the metal printing module to perform arc additive manufacturing of metal material, and performs parameter control of the composite process during the composite printing process to complete the integrated construction of reinforced concrete composite structure.

2. The metal-concrete composite additive manufacturing system according to claim 1, characterized in that, The system also includes a gantry printer, which comprises a gantry frame and ground rails; the movement paths of the gantry frame are arranged in parallel; a transverse track is provided between the movement paths, and a transverse trolley is provided on the transverse track; the gantry frame can move along the ground rails to the transverse trolley, and the transverse trolley can move along the transverse track; the transverse trolley is used to move the gantry frame from one set of ground rails to another set of ground rails; the gantry frame is connected to at least one robotic arm, which can move along the gantry frame crossbeam and can selectively mount a concrete print head or a metal print head.

3. The metal-concrete composite additive manufacturing system according to claim 1, characterized in that, The central control system is specifically configured as follows: during the composite printing process, the metal printing module is controlled to melt and deposit metal material layer by layer or segment by segment to form a steel reinforcement skeleton or metal structure layer, and the concrete printing module is controlled to print concrete material inside or outside the already formed steel reinforcement skeleton or metal structure layer, so that metal printing and concrete printing are performed alternately in a preset order.

4. The metal-concrete composite additive manufacturing system according to claim 3, characterized in that, The metal printing module includes an arc welding gun, a wire feeding mechanism, a welding power source, and a shielding gas supply device; the concrete printing module includes a concrete pumping system, an extrusion nozzle, and a material mixing device. The central control system is electrically connected to the arc welding gun, wire feeding mechanism, welding power source, hot wire power source, water cooling device, protective gas supply device, concrete pumping system, extrusion nozzle and material mixing device, respectively. It is used to control the metal printing module to form a steel reinforcement skeleton or metal structure layer in a preset alternating sequence, and to control the concrete printing module to print concrete material inside, outside or between layers of the steel reinforcement skeleton or metal structure layer.

5. The metal-concrete composite additive manufacturing system according to claim 1, characterized in that, The central control system includes a gantry frame control submodule, a track rotation motion control submodule, a robotic arm motion control submodule, and a composite process control module. The gantry frame control submodule is used to control the gantry frame's moving speed, moving position, and acceleration / deceleration curve along the ground rail, and to control the precise positioning of the gantry frame at the docking point of the transverse track. The track-switching motion control submodule is used to control the movement of the traverse trolley along the traverse track, and to control the unlocking of the gantry frame from the current ground rail, the docking and locking of the traverse trolley, and the relocking and coordinate mapping update of the gantry frame on the target ground rail. The robotic arm motion control submodule is used to control the movement path of the robotic arm along the crossbeam of the gantry frame and the spatial trajectory of the robotic arm end effector. The composite process control module is used to control the printing process parameters of the concrete print head or the metal print head, including extrusion speed, wire feeding speed, welding current and voltage, and multi-welding gun coordination.

6. The metal-concrete composite additive manufacturing system according to claim 1, characterized in that, The central control system is also configured for composite additive manufacturing collaborative control, including: When generating the composite printing path plan, a heat-affected zone is set for each metal printing segment, and the spatial path of the subsequent concrete printing segment is made to avoid the heat-affected zone; a forced waiting time is set for each metal printing segment, and the starting point of the forced waiting time is the end time of the most recent concrete printing.

7. The metal-concrete composite additive manufacturing system according to claim 1, characterized in that, The central control system is also configured to perform master-slave collaborative control, including: When the first gantry crane needs to enter the current working area of ​​the second gantry crane, the central control system issues an avoidance command to the second gantry crane, controlling the second gantry crane to move along the ground rail to a preset waiting position; The central control system receives the ready signal from the second gantry crane and, after confirming that the work area is cleared, sends an entry permission signal to the first gantry crane, controlling the first gantry crane to enter the work area.

8. The metal-concrete composite additive manufacturing system according to claim 7, characterized in that, The master-slave collaborative control also includes: After the first gantry frame enters the work area, when the first robotic arm driving the concrete printing head is about to enter the work sub-area of ​​the second robotic arm driving the metal printing head and the spatial distance is less than the minimum safe space distance, an intrusion request signal is sent to the second robotic arm. Before receiving the permission signal issued by the second robotic arm in response to the intrusion request signal, control the second robotic arm to interrupt the current metal printing task and retreat to a safe waiting position; Upon receiving the permission signal, the first robotic arm is controlled to enter the work sub-area to perform the concrete printing task; Once the concrete printing task is completed, the second robotic arm is controlled to return to the interruption point to resume the metal printing task.

9. The metal-concrete composite additive manufacturing system according to claim 1, characterized in that, The central control system is also configured to perform gantry crane cross-rail transfer control, including: The gantry crane is controlled to pause operation and return to a safe position, then moved to the docking point of the transverse track and engaged with the transverse trolley. Unlock the connection to the current orbit and switch to backup power; The drive traverse trolley moves the gantry frame to the target ground rail, aligns and locks it, restores main power and communication, updates coordinate mapping, and continues operation on the new ground rail.

10. The metal-concrete composite additive manufacturing system according to claim 5, characterized in that, The composite process control module is also configured to perform multi-welding gun collaborative control, including: The number of welding guns to be used is determined based on the dimensions of the printed structural components and the distribution pattern of the reinforcing bars, and the corresponding number of target welding guns are selected in the corresponding metal printing segment. The digital output port sends a synchronous arc ignition start signal to the welding power supply and wire feeding mechanism corresponding to the selected welding torch, enabling multiple welding torches to weld in parallel. A synchronous arc extinguishing stop signal is issued at the end of the printing segment.

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