Four-arm construction robot apparatus having upper main arms and lower auxiliary arms

Abstract

The present invention relates to a four-arm robot equipment for construction, wherein an upper shoulder section and a lower shoulder section that rotate independently of each other are coupled to a shared waist section on a movable body, a pair of main arms with a long reach are coupled to the upper shoulder section, and a pair of auxiliary arms with a short reach are coupled to the lower shoulder section, and a grip head for gripping construction materials or work tools is provided at the end of each arm. The main arms perform primary processes such as 3DP output, masonry, and rebar placement, while the auxiliary arms perform subsequent processes such as surface treatment and joint finishing. The pitch joints of each arm are linearly driven by an inverted slider-crank mechanism, and a movable counterweight linked to the slider offsets the shift in the center of gravity due to changes in posture, thereby minimizing the holding torque. The arm mounting surfaces of the shoulder section are arranged on the inclined plane of a virtual pyramid with its vertices facing forward, so that the working areas of the four arms are concentrated at the front, and three-point outriggers consisting of two points at the front and one point at the rear center determine the reference plane of the equipment. The four arms are stored along the length of the vehicle body by a folding actuator, allowing for standard container transport, and the posture is maintained even in the event of power loss by a motor with a built-in brake and a self-locking reduction gear mechanism.

Description

Technology Field

[0001] The present invention relates to a multi-joint robot equipment for construction, and more specifically, to an asymmetric 4-arm construction robot equipment in which an upper shoulder part and a lower shoulder part are independently rotatably coupled to a shared waist part on a movable body, a pair of main arms are coupled to the upper shoulder part, and a pair of auxiliary arms with a reach length shorter than that of the main arms are coupled to the lower shoulder part, so that four multi-joint arms perform collaborative work on a single construction work object.

[0002] The present invention is intended to resolve the problems of distal end sagging due to self-weight, a rapid increase in joint load moment, and self-multiplication of joint drive weight occurring in long-reach multi-joint arms, particularly those reaching several meters in length, through a mechanical link arrangement structure comprising a reversing slider-crank mechanism and a movable counterweight coupled thereto. Background Technology

[0003] In the robotization of construction work, attempts are being made to replace human-scale indoor work (interior finishing, etc.) with humanoid robots. However, construction work on the exterior of a building typically requires the installation of scaffolding, which not only incurs significant costs and time for installation and dismantling but also involves workers performing tasks at heights, making it a major cause of falls among construction accidents. Human-scale robots with a reach of approximately 2 meters cannot perform such external high-altitude work from the ground.

[0004] Therefore, for the robotization of building exterior work, long-reach equipment exceeding the human scale is required, which can cover the entire exterior construction work of a low-rise building (e.g., two stories) with equipment located on the ground. Such equipment serves as a means to ensure safety by eliminating the need for temporary scaffolding, thereby removing the need for workers to work at heights. The long-reach configuration of the present invention originated from this requirement.

[0005] In addition, since a building site typically faces a road on only one side, the entry, exit, installation, and removal of equipment must be possible from the exterior of the building. A construction method where equipment is placed inside the building is not practical because the equipment becomes trapped inside the building as construction progresses, and large equipment cannot be removed through doors with an effective width of typically 900mm. For this reason as well, a long-reach configuration that covers the entire construction from the outside of the building is required.

[0006] In the field of construction automation, construction 3D printing (3DP) equipment that extrudes cementitious materials and masonry robots that grasp and stack bricks are known. However, most of these machines have a single arm or single head structure, so each machine performs only one process. For example, a known masonry robot has a single arm structure and performs only brick stacking, while related processes such as mortar application, rebar placement, and surface finishing require separate personnel or equipment.

[0007] In the field of industrial robots, dual-arm robots combining two arms into a single body are known. However, known industrial dual-arm robots are small devices with a reach of approximately 2 meters designed for indoor manufacturing environments, relying on high-precision rigid links and expensive precision reducers. If this structure is expanded to a reach of several meters or more required by construction sites, the weight required to secure link rigidity increases the torque required by the joint actuators, and the increased weight of the actuators further increases the link load due to a self-replicating problem, causing the equipment weight and cost to increase exponentially. In other words, since single-arm structures have become the standard in industrial settings, dual-arm structures have remained at a stage where they are mainly adopted in small indoor manufacturing robots or humanoid robots, and a configuration in which two dual-arm robots are stacked vertically to share a single waist and rotate each shoulder independently is not known.

[0008] There are also prior art documents regarding multi-arm robots. Patent documents 1 and 2 disclose a robot device equipped with multiple manipulators, patent document 3 discloses a two-arm robot, patent document 4 discloses an array of four manipulator arms per cluster, and patent document 5 discloses a four-arm robot for transport with four arms arranged on both sides of the torso and in front. However, all of these are intended for indoor manufacturing lines or transport applications and fail to simultaneously address the long reach required at outdoor construction sites, the handling of heavy materials, the storability for road transport, and the safety of maintaining posture in the event of power loss.

[0009] In Korea, there are known autonomous construction work robots (Patent Document 20) in which multiple types of work modules, such as multi-joint arms, are detachably mounted on the four sides of a cube-shaped body, 16-axis industrial dual-arm robots (Patent Document 21) in which a bending axis is added to both arms to expand the work area, and dual-arm robot devices for parts assembly (Patent Document 22). However, Patent Document 20 is a small detachable modular robot for indoor flooring installation in which the arm modules are individually coupled to the sides of the body, and Patent Documents 21 and 22 are single-shoulder dual-arm robots based on an indoor manufacturing environment, and do not suggest an outdoor long-reach 4-arm configuration in which two pairs of upper and lower shoulder sections rotate independently and two pairs of arms with different reach lengths cooperate.

[0010] Meanwhile, long-reach construction heavy equipment of the excavator series has a reach of more than 18m, but as a single-arm hydraulic structure with approximately 3 degrees of freedom, it cannot perform precision construction work in the millimeter range and has only a single work area.

[0011] In terms of individual mechanism elements, an inverted slider-crank mechanism that drives a rotary joint with a linear actuator is a known type of mechanism that has been employed for decades as a boom and arm drive mechanism for hydraulic excavators, and a robot arm based on a slider-crank mechanism (Patent Document 7), a gravity compensation mechanism of a robot arm by a counterweight (Patent Documents 8 to 10), and a robot joint configuration with the arm mounting surface inclined at approximately 45° (Patent Document 11) are individually known.

[0012] However, these disclosed elements are limited to being proposed as individual mechanisms for single-arm or indoor small robots, and no configuration is disclosed in any literature that mechanically links the position change of the arm and the position of the weight by using the slider frame of the inverted slider-crank mechanism itself as a moving carrier for the counterweight without a separate driving source, a configuration that converges the working area of ​​multiple arms to the front of the equipment by means of shoulder mounting surfaces that are double inclined forward and sideways, and a configuration that combines these into an asymmetrical four-arm structure of upper and lower independent rotating shoulders.

[0013] Meanwhile, in accordance with the trend of electrification of construction machinery, attempts to combine hydraulic actuators with electric systems (Patent Document 14), linear actuators for industrial robots using a feed screw and a slider (Patent Document 12), and configurations in which a screw actuator is placed inside a leg member of a walking robot (Patent Document 13) are known. However, these are limited to replacing a cylinder-type actuator with its original shape or relate to individual joint driving of small robots, and an inverted slider-crank arrangement in which the entire drive system is integrated within the cross-sectional contour of the arm member by aligning the feed screw and the drive motor in close contact with the upper arm member of a long-reach arm in parallel is not disclosed.

[0014] Regarding counterweights, auxiliary counterweights for fluid transfer arms rotatably mounted at the rear of a support and linked by pulleys and cables (Patent Document 23), jib for a camera having double counterweights linked by a link rod and a lever arm (Patent Document 24), counterweights for a mobile crane attached to a boom (Patent Document 25), and walking robots that self-compensate for the mass of the main body (Patent Document 28) are known. Meanwhile, gravity compensation for industrial robots is predominantly spring or gas cylinder types due to constraints on indoor installation space, and mass-type counterweights are mainly adopted in large equipment where space is available (e.g., tower cranes that move counterweights in real time according to the position of the load, see Patent Document 29). However, all of the above documents require separate linkages, pulleys, or dedicated drives for moving the weight, and do not disclose a configuration in which the slider frame itself of a reversing slider-crank for joint drive is used as a moving carrier for the weight. In addition, a foldable concrete pouring boom (Patent Document 26) and a direct-acting joint drive device (Patent Document 27) are also known as individual elements.

[0015] In short, existing construction heavy equipment is specialized for destructive and transport tasks requiring great force, such as excavation, crushing, and lifting, while precision work involving construction remains the responsibility of humans. Meanwhile, factory 6-axis robot arms are specialized for precise repetitive tasks in standardized indoor environments and cannot be applied to outdoor construction environments. In other words, the intermediate area between the toughness of construction heavy equipment and the precision of industrial robots—an area where construction work is performed with construction tolerance-level precision in the rough environment of a construction site—remains a void, and the present invention relates to a construction robot that fills this void.

[0016] Therefore, there is a demand for a multi-joint robot for construction that can cover multiple construction processes such as 3DP output, masonry, rebar placement, window installation, and surface finishing with a single piece of equipment, while avoiding the self-increasing weight and cost associated with long reach and large size, and can be folded and stored in standard transport dimensions. Prior art literature

[0017] US 4,407,625 (MULTIARM ROBOT)US 5,438,647 (MULTI-MANIPULATOR ROBOT APPARATUS)US 8,951,002 (DUAL ARM ROBOT)EP 1 428 166 B1US 11,701,781US 2007 / 0295136 A1 (ANTI-BACKLASH GEAR SYSTEM)WO 2000 / 040378 A1 (SLIDER CRANK MECHANISM BASED ROBOT ARM)US 9,314,934 B2 (GRAVITY-COUNTERBALANCED ROBOT ARM)US 2015 / 0040712 A1 (GRAVITY COMPENSATION MECHANISM AND ROBOT)DE 40 14 003 A1 (Parallelogram linkage linkage Counterweight Industrial Robot) US 9,120,229 B2 (Robot Arm with 45° Inclined Mounting Surface) US 5,099,707 (Industrial Robot Linear Actuator with Feed Screw) US 11,131,368 (Screw Actuator in Leg Member of Walking Robot) US 11,268,263 (Electric Excavator) US 4,570,065 (ROBOTIC COMPENSATION SYSTEMS) US 5,648,617 (SINGLE AXIS ROBOT FORCE SENSOR ASSEMBLY) US 4,456,293 (ARTICLE GRIPPING APPARATUS - Sector Gear and 4-Bar Link Gripper) US 9,296,113 B2 (DELTA ROBOT AND LINEAR DELTA MECHANISM - Vertical Column / Carriage Type Linear Delta) CN 103203728 A (Leveling method for a 3-point support platform) KR 10-2431336 B1 (Multipurpose autonomous work robot system for construction) KR 10-1410245 B1 (16-axis industrial dual-arm robot) KR 10-1551093 B1 (Dual-arm robot assembly device) US 4,418,718 (Auxiliary counterweight control of fluid transfer arm - Expired) US 8,746,634 B2 (Jib for camera with link-linked dual counterweight) US 11,447,374 B2 (Crane Counterweight and Suspension) US 3,964,512 (Self-supporting Folding Pipe Boom - Expired) US 6,703,725 B2 (Linear Joint Actuator - Expired) US 12,263,899 B2 (Walking Mobile Robot with Self-compensating Mass) US 2011 / 0278252 A1 (Real-time Control of Mobile Counterweight of Tower Crane),

[0018] Mitrev, R. et al., "Inverted Slider-Crank Mechanism Driven by Hydraulic Cylinder: Transfer Functions and Approximations", Engineering Mathematics, Vol. 6, No. 1 (2022)Thomson Industries, "Electric Actuator Advancements Expand Options for Replacing Hydraulic Cylinders", https: / / www.thomsonlinear.com (2026. 7. 2. 검색)HEIDENHAIN, "Why dual encoders are the right choice for robotics design", https: / / www.heidenhain.us (2026. 7. 2. 검색)"Innovative vibration damping on truck-mounted concrete pumps with strain sensors", Engineering Update (2018. 12. 13., 2026. 7. 2. 검색)Segla, S., "Adaptive Balancing by Counterweights of Robots and Mechatronic Systems" (2018)Ciupitu, L., "The static balancing of the industrial robot arms, Part I: Discrete balancing" (2013)"Dual-Arm Construction Robot for Automatic Fixation of Structural Parts to Concrete Surfaces in Narrow Environments", arXiv:2403.19948 (2024)"Robotic mechanical design for brick-laying automation", Cogent Engineering, Vol. 4 (2017)Bouri, M.and Clavel, R., "The Linear Delta: Developments and Applications", International Symposium on Robotics (2010) Graves, S., "Rostock Style Delta Robot Kinematics", RepRap.org (Published in 2012, accessed July 3, 2026) "Control strategy of three-point supported automatic levelling platform" (2016) "US 155-mm Howitzer", warhistory.org, https: / / warhistory.org / article / us-155-mm-howitzer (Accessed July 3, 2026) - Record of three-point support by firing jack descent and wheel disengagement of the M114 howitzer. The problem to be solved

[0019] The four-arm configuration of the present invention is not an arbitrary increase in the number of arms, but is derived stepwise from the work requirements of a construction site as follows. For 3D printing output only, one arm is sufficient (see Applicant's prior application No. 10-2026-0007769). However, in slab construction where heterogeneous materials are extruded in parallel, the operation of two heads is required (see Applicant's prior applications No. 10-2026-0030174, No. 10-2026-0030184 and No. 10-2026-0084929), and in masonry construction, a grip head is required in which the other arm grips and stacks bricks while one arm extrudes mortar. When a grip head is introduced, the 3DP head itself can be separated into a gripping extension (tool), allowing both arms to be operated in a gripping manner (this is based on material and head technology that does not require hose cleaning when discharge is stopped, and such material and head technology is disclosed in the applicant's prior Korean patent applications No. 10-2026-0030174 and No. 10-2026-0030184).

[0020] Furthermore, in construction where permanent formwork for reinforced concrete (RC) structures is 3D printed and reinforcing bar bundles are inserted inside, high-load specifications are required for the cooperative grip of both arms, and this is reflected in the counterweight capacity design of the inversion slider-crank described later. In addition, when installing large construction components such as windows and doors, a cooperative grip of both arms is more advantageous than a large single-arm grip in irregular site environments, so both arms are in a state of gripping the component, and a separate hand is required to perform fastening work. From the need for a hand to fasten and finish in addition to the two gripping hands, the lower auxiliary arms were derived, and since the lower arms face the lower wall already constructed by the upper arms, they resulted in lightweight, small auxiliary arms responsible for subsequent surface work and installation assistance.

[0021] The first problem that the present invention aims to solve is to enable a single piece of equipment to continuously perform multiple construction processes by dividing roles between two pairs of multi-joint arms having different heights and reach lengths—whereby the upper main arm performs heavy and main processes such as 3DP output, masonry, rebar placement, concrete pouring, and lifting windows and doors, and the lower auxiliary arm performs subsequent and finishing processes such as wall surface treatment, masonry joint finishing, and drill fastening.

[0022] The second objective is to achieve miniaturization and cost reduction of the drive unit by mechanically offsetting the gravitational torque and holding torque acting on the joints of the long-reach multi-joint arm using a reversing slider-crank mechanism and a counterweight that moves in conjunction with it, rather than by increasing the capacity of expensive precision reducers.

[0023] The third task is to store large equipment, including four arms and shoulder parts, into the upper part of the vehicle body by folding the joints so that the entire equipment can be stored within road transport standards such as standard containers.

[0024] The fourth task is to ensure safety by mechanically maintaining the posture of the arm and shoulder even in the event of power loss at an outdoor construction site, and to ensure construction precision within construction tolerances through coordinate system correction based on measurement data from sensors placed on the equipment. means of solving the problem

[0025] A construction 4-arm robot equipment according to one aspect of the present invention for solving the above problem comprises: a movable vehicle body; a shared waist portion erected on the vehicle body; an upper shoulder portion and a lower shoulder portion arranged vertically on the shared waist portion and each rotated independently of each other through a rotational bearing; a pair of main arms having a first reach length as multi-joint arms of 6 axes or more coupled to both sides of the upper shoulder portion; a pair of auxiliary arms having a second reach length shorter than the first reach length as multi-joint arms of 6 axes or more coupled to both sides of the lower shoulder portion; and a grip head provided at the end of each of the main arms and auxiliary arms to grip construction materials or work tools.

[0026] With the above configuration, the equipment operates in a form in which two dual-arm robots, each having its own shoulder rotational degrees of freedom and control sensors, are stacked vertically on a single shared waist section. A hierarchical four-arm structure is formed in which the upper arms handle the main process at a long distance with a long reach, and the lower arms handle the subsequent process at a short distance with a short reach.

[0027] In one embodiment, the arm mounting surfaces of the upper and lower shoulder portions are positioned on different inclined planes of a virtual pyramid with vertices facing the front of the equipment, and are double inclined forward and laterally, and the main arm is mounted to approach the workspace in an elbow-upward and the auxiliary arm in an elbow-downward bending position, so that the convergence area of ​​both arms is concentrated toward the front of the equipment and collision between the four arms is avoided.

[0028] In one embodiment, at least one of the pitch joints of each arm is linearly driven by an inversion slider-crank mechanism in which a slider frame extends to the rear of the upper arm member, and a counterweight moving in conjunction with the slider offsets the shift in the center of gravity due to changes in the arm's posture.

[0029] In one embodiment, the outrigger installed deployably on the vehicle body is composed of three-point support consisting of two points on both sides at the front and one point at the center at the rear, wherein the two points at the front independently determine the lateral inclination of the equipment and the one point at the rear independently determines the longitudinal inclination, thereby geometrically uniquely determining the reference plane of the equipment.

[0030] In one embodiment, by means of a folding actuator provided at the base joint of each arm and a releaseable structural fastening part, the four arms are folded in the longitudinal direction of the vehicle body during transport, so that the entire equipment is stored within the standard container transport dimensions.

[0031] In one embodiment, the device further includes a control unit that corrects the static position error between the initial driving coordinate system of the equipment and the arm end based on data measured from a control sensor unit fixedly positioned on the shoulder portion, a camera positioned on the joint portion and the end portion of the arm, and a horizontal level sensor positioned on the vehicle body and the outrigger. Effects of the invention

[0032] According to the present invention, while a pair of upper main arms perform the main construction process, a pair of lower auxiliary arms perform the finishing and subsequent processes of the lower part of the already created wall in parallel, so that work previously performed by multiple single-arm or double-arm equipment and auxiliary personnel can be performed by one piece of equipment in a continuous pipeline.

[0033] In addition, since the upper shoulder and lower shoulder parts rotate independently of each other, the four arms can each maintain an optimal working orientation even if the upper construction surface and the lower finishing surface are in different orientations.

[0034] In addition, due to the inverted slider-crank mechanism and interlocking counterweight, the joint drive motor bears only the dynamic torque during acceleration and deceleration while the holding torque is minimized; thus, multi-meter-class long-reach arms can be driven with general-purpose servo motors and commercially available reduction components, resulting in a significant reduction in equipment costs.

[0035] In addition, the entire equipment fits within standard container shipping dimensions thanks to its articulated folding mechanism, making inter-site movement and overseas transportation easy.

[0036] In addition, the position of the arm and shoulder is mechanically maintained by the worm gear type self-locking drive unit even in the event of power loss, thereby ensuring safety in outdoor sites.

[0037] In addition, through coordinate system correction based on measurement data from the shoulder fixed control sensor, end camera, and horizontal level sensor, deflection and assembly errors occurring in the lightweight structure can be absorbed, thereby ensuring construction precision within architectural tolerances.

[0038] In addition, due to the double inclined mounting surface of the shoulder, the four arms approach the front working space of each shoulder in the shortest possible position, and the mutual collision between the working parts of the upper and lower shoulders and the rear counterweight part is geometrically avoided, and due to the inclination of the joint rotation surface, a significant portion of the gravitational torque caused by the arm's own weight is supported by the structural reaction force of the joint hinge, thereby significantly reducing the capacity and cost of the joint drive unit.

[0039] Furthermore, according to the present invention, the installation and dismantling of scaffolding are eliminated during the exterior construction of low-rise buildings, and work at heights by workers is removed; thus, the risk of falling, which is a major cause of construction accidents, is fundamentally eliminated, and installation costs and construction time are reduced.

[0040] Furthermore, the present invention integrates the previously separate dedicated robots for each discrete construction process—such as 3DP output, masonry, rebar placement, member installation, and surface finishing—into a single piece of equipment. Moreover, the precise setting of a reference plane using three-point support facilitates the alignment of the equipment's digital model with its actual posture (digital twin-based operation), and combined with a sensor system fixed to the shoulder, it provides a hardware platform for future learning-based control. Brief explanation of the drawing

[0041] FIG. 1 is an overall perspective view of a four-arm robot equipment for construction according to one embodiment of the present invention. FIG. 2 is a front perspective view of the above equipment, illustrating the arrangement of the shared waist section, upper and lower shoulder sections, four arms, control tower, and control sensor section. FIG. 3 is a rear perspective view of the equipment in operation, illustrating the arrangement of the shoulder rotation part, material container, extension mounts for the upper and lower arms, maintenance opening, outrigger, and hydraulic cylinder. FIG. 4 is a side view of the equipment in operation, illustrating the arrangement of the upper arm slider frame, movable counterweight, control unit, and fixing hook for loading cargo. FIG. 5 is a conceptual diagram illustrating a pyramid-shaped inclined mounting surface of a shoulder portion, wherein (a) shows the actual shape of the upper shoulder portion and the lower shoulder portion, (b) shows the polyhedral shape of the upper shoulder mass and the lower shoulder mass extracted therefrom, and (c) shows a virtual pyramid (P) in which the polyhedra are inscribed and the vertices face forward, and each arm mounting surface. FIG. 6 is a configuration diagram showing the 6-axis joint configuration of the unit arm, the inversion slider-crank mechanism, the movable counterweight, the hydraulic cylinder for folding, and the state after folding (F) indicated by the dashed line (virtual line). FIG. 7 is a conceptual plan diagram illustrating the arrangement of three-point outriggers and the support triangle (T), center of gravity (G), and column position of the shared waist determined by this arrangement. FIG. 8 is a perspective view of the transport state in which four arms are folded and stored within a standard container (C). Specific details for implementing the invention

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, the following embodiments are examples to aid in understanding the present invention, and the scope of the present invention is not limited thereto.

[0043] Referring to FIG. 1, the construction 4-arm robot equipment (1) according to the present embodiment is broadly divided into a movable base unit (2) responsible for support stability, transportation, and supply of materials and extensions at the bottom of the equipment, and an arm-driven robot unit (3) that performs work on a shared waist unit. Referring together to FIG. 2, the equipment (1) includes a movable vehicle body (10), a shared waist unit (40) installed on the vehicle body (10), an upper shoulder unit (41) and a lower shoulder unit (44) arranged vertically on the shared waist unit (40), a pair of main arms (50: 50L, 50R) coupled to both sides of the upper shoulder unit (41), a pair of auxiliary arms (60: 60L, 60R) coupled to both sides of the lower shoulder unit (44), and a plurality of outriggers (12) that are deployably installed on the vehicle body (10). Each end of the main arm (50) and the auxiliary arm (60) is equipped with a grip head (59) for gripping construction materials or work tools.

[0044] The vehicle body (10) may be configured as a self-propelled bogie by means of a moving wheel (11). The vehicle body (10) is equipped with a total of three outriggers: outriggers (12a, 12b) on both front sides and an outrigger (12c) in the rear center. The front outriggers (12a, 12b) are first extended sideways in a hinged manner by an outrigger hydraulic cylinder (20c), and secondly, a vertical cylinder built into each outrigger (12a, 12b, 12c) extends to the ground and sets a horizontal level. The rear center outrigger (12c) operates only with vertical extension without sideways extension. The set height is mechanically fixed by a level fixing screw (14) and maintained even during long-term operation. If the level collapses due to ground subsidence or other reasons during operation, a horizontal level sensor (13) positioned at multiple locations on the outrigger (12) and the vehicle body (10) detects this, issues a warning, and corrects the level.

[0045] Referring to FIG. 7, the outrigger (12) can be operated as a three-point support consisting of two points (12a, 12b) on both sides of the front of the vehicle body and one point (12c) at the rear center. Unlike conventional construction equipment that uses four-point outriggers for the purpose of preventing rollover, this equipment utilizes the property that three points geometrically uniquely determine a single plane. That is, the reference plane of the equipment is precisely horizontally set without excessive constraint by only adjusting the vertical extension amount of the three points, and this reference plane becomes a virtual construction reference plane that extends to the work area. This is intended to ensure the accuracy of construction data-based control by minimizing the discrepancy between the digital model of the equipment and the actual posture, and the arrangement of the three-point horizontal posture control is common to the triangular arrangement configuration of the applicant's prior application No. 10-2026-0007769.

[0046] The principle of horizontal setting by three-point support itself is known in the field of surveying instruments and precision measurement platforms (see Patent Document 19 and Non-Patent Document 11). However, in the field of construction heavy equipment, it is technical common sense to adopt four-point outriggers to ensure safety margins against rollover, and as a result, the uncertainty of ground load and distortion of the reference plane caused by four-point indeterminate support have been accepted. Unlike this technical common sense, the present invention introduces the three-point support principle of the precision measurement field into heavy equipment outriggers, while satisfying the stability conditions resulting from the three-point configuration as follows. In other words, since the equipment has four arms and the working load concentrated at the front, and the center of gravity is located ahead of the centroid of the support triangle, the main risk of overturning is forward tipping. By widely extending the two front points (12a, 12b) in the working direction to secure the front side of the support triangle sufficiently ahead of the center of gravity—so that the center of gravity is ahead of the centroid but does not exceed the front side connecting 12a and 12b—forward tipping is prevented, and the material storage container and counterweight load at the rear act in a direction that restores the center of gravity toward the centroid.

[0047] Meanwhile, in fields other than vehicle-mounted equipment, it is known that towed howitzers adopt a three-point support system in which the wheels are lifted off the ground during firing, consisting of one firing platform under the axle and two spade points of a split trail extending to the rear (see Non-Patent Literature 12). However, this is a fixed support intended to secure static stability against firing recoil, and its purpose and configuration differ from the three-point outrigger of the present invention, which actively adjusts the vertical extension of each support point to precisely set the reference plane of the equipment. Furthermore, the arrangement direction of the support points is opposite to that of the present invention (two points in the front, which is the working direction, and one point in the rear center). This difference in arrangement direction is due to the directionality of the load. In other words, since the firing direction of a towed howitzer is practically fixed (only the angle of inclination is adjusted after rough aiming based on the parking direction) and the recoil load is directed towards the rear, two points are placed at the rear. In contrast, since the shoulder of this equipment rotates and the self-weight of the arm and the working load are concentrated in the forward working direction, if the same arrangement as a howitzer is adopted, there is only one central support point at the front, so the left and right support width on the front side where the load is concentrated is not secured, and when the arm and load are directed sideways due to the rotation of the shoulder, tilting occurs. Therefore, the present invention adopts a support triangle in the opposite direction to that of a howitzer. Furthermore, even in the case of a vehicle-mounted howitzer, support is provided by using a combination of rear spades and wheels (where the wheel suspension system intervenes, making it impossible to set a precise reference plane) or by employing a four-point hydraulic jack; a configuration that supports the equipment using only three active outriggers while the wheels are completely lifted off the ground is not known.

[0048] Three-point support is also advantageous from the perspective of the horizontal setting procedure. The sides formed by the front outriggers (12a, 12b) independently determine the lateral (X-axis) tilt of the equipment, and the rear center outrigger (12c) independently determines the longitudinal (Y-axis) tilt. Therefore, the setting of the reference plane is completed with only two sequential adjustments: first, the lateral horizontal alignment matching the front work area is set using the vertical extension of 12a and 12b, and then the longitudinal horizontal alignment is set using the extension of 12c. Since a triangle is the minimum unit defining a plane, the adjustments of each axis do not interfere with each other, and the repetitive adjustments or frame twist correction required in four-point support are unnecessary.

[0049] In the specific configuration of the support triangle, it is desirable to have the deployment width of the front outriggers (12a, 12b) within approximately three times the full width of the equipment, and the difference in length between the three sides of the support triangle (T) within approximately 20%, so that it is in a shape close to an equilateral triangle. This is because if the difference in side lengths is excessive, the stability margin in a specific direction decreases rapidly. In addition, the center of gravity (G) of the equipment and the center axis (O) of the shared waist portion (40) must be located inside the support triangle (T), and this condition must be maintained including changes in posture and gripping load during operation. Since forward tipping occurs when the center of gravity under load exceeds the front side (the side connecting 12a and 12b), the maximum load that can be gripped at the maximum reach length is determined from this condition.

[0050] The shared waist section (40) is a waist column that is erected on the vehicle body (10), and does not rotate itself, but supports the upper shoulder section (41) and the lower shoulder section (44) to share a single torso. The upper shoulder section (41) and the lower shoulder section (44) each rotate independently relative to the shared waist section (40) through a gear rotation bearing. That is, the equipment can be understood as a form in which two two-arm robots are combined vertically while sharing a single shared waist section.

[0051] Referring to FIGS. 2 and 3, the upper shoulder portion (41) is driven to rotate independently by the upper shoulder rotation portion (42), and the lower shoulder portion (44) is driven independently by the lower shoulder rotation portion (45). A cross roller bearing (47) is interposed between the upper shoulder portion (41) and the lower shoulder portion (44) to support the relative rotation of the two shoulder portions. Accordingly, the two shoulder portions can simultaneously maintain different orientations so that the upper main arm (50) faces the construction surface of the upper part of the building and the lower auxiliary arm (60) faces the finishing surface of the lower part of the already created wall.

[0052] The arm mounting surfaces (43, 46) of each shoulder portion (30, 40) can be formed as inclined convergence surfaces that are inclined forward (e.g., about 10° to 30°) and inclined laterally (e.g., about 30° to 60°). Due to these inclined mounting surfaces, the working area of ​​both arms naturally converges into the working space at the front of the equipment, the gravitational torque burden on the arm base joint is reduced, and a rotational margin is secured so that the left and right arms do not collide with each other at the rear.

[0053] The technical significance of the above-mentioned inclined mounting surface is as follows: First, the standard for the inclination is not the front of the parked vehicle body, but the working front of each of the upper and lower shoulder sections, allowing the four arms to approach the front working space of each shoulder in the shortest possible posture. Second, the angle of inclination is determined by the condition that the front working sections of the upper and lower shoulders do not interfere with each other, and that the slider frame and counterweight section extending to the rear of each arm do not collide with adjacent arms and upper structures. Third, if the lateral angle of inclination is set to approximately 45°, a semi-SCARA configuration is formed in which the rotational plane of the pitch joint of each arm is inclined with respect to the direction of gravity. Consequently, a significant portion of the gravitational torque caused by the arm's own weight is transferred to the structural reaction force of the joint hinge rather than the joint drive motor, thereby reducing the burden on the drive motor by approximately half. In other words, the above-mentioned inclined mounting surface is a modified configuration for long reach.

[0054] As a specific arrangement of the above-mentioned inclined mounting surfaces, the mounting surfaces of the upper and lower shoulder parts can form a diamond-shaped (rhombus-shaped) inclined surface arrangement that spreads upward, downward, left, and right around a forward-facing vertex. In this case, the upper main arm approaches the workspace from above in an upward bending posture with the elbow joint raised higher than the shoulder, similar to a conventional industrial robot arm, while the lower auxiliary arm approaches the workspace in a downward bending posture with the elbow joint lower than the shoulder, similar to a human body or a humanoid robot. Due to these upward and downward opposite bending directions, the slider frames and counterweights of the inverted slider-cranks extending to the rear of the upper arms of each of the four arms are oriented in opposite directions upward and downward, respectively; thus, the four rear protrusions do not collide with each other around the shared waist area. In other words, the diamond-shaped inclined surface and the upward and downward opposing bending posture are a prerequisite structure for applying slider-linked counterweights to all four arms.

[0055] The effect of the aforementioned inclined mounting surface is derived from the geometric characteristics of the dual-arm configuration as follows. Applying an inclined base to a single arm alone does not provide any particular advantage. On the other hand, in a dual-arm configuration where a pair of arms face each other, a convergence zone where the reach areas of both arms meet is formed on both the front and rear sides of the equipment. If the mounting surface is tilted only laterally (1st inclination), a reduction in gravitational burden due to the inclination of the joint rotation plane on both the front and rear sides (the aforementioned anti-SCARA configuration) is achieved; however, the convergence zone becomes dispersed forward and backward, resulting in a shorter effective reach relative to the front. Furthermore, if the mounting surface is tilted forward once more (2nd inclination), the convergence zone on the rear is reduced or eliminated, allowing a wider area to be covered on the front with a shorter reach. In other words, the double inclination is a configuration that concentrates the working capacity of both arms into the front working area.

[0056] As such, since the work area is concentrated on the front of the shoulder section, when the shoulder section rotates due to the rotation of the shoulder rotation section (42, 45), the front of the shoulder section, rather than the front of the parked vehicle body, becomes the work area, thereby securing a work area in all directions around the equipment. In addition, since the control sensor section (71, 72) fixed to the shoulder section always faces the same orientation as the work area, the alignment between the camera image and the work scene is maintained consistently, which is advantageous in terms of consistency in data collection for subsequent learning-based control.

[0057] Furthermore, when the rear convergence area is reduced by the double slope, the rear collision margin of the slider frame (53) and counterweight (54) extending to the rear of each arm is also expanded, or the possibility of collision itself is eliminated. As shown in FIG. 6, the slider frame for the upper arm on which the counterweight is mounted can be positioned so that it is raised about 30° upward with respect to the rotational bearing plane of the first joint (J1), which is a position to maximize the effective joint rotation angle of the upper arm toward the front while avoiding rear collision.

[0058] In addition, due to the double slope, the mounting surfaces of the upper and lower shoulder sections form a pyramid shape that protrudes forward (see FIG. 5), and since the working area of ​​each arm is separated by spreading forward, collisions between the left and right arms of the same shoulder are fundamentally prevented, and the possibility of collision between the upper and lower arms is also minimized. Accordingly, it becomes possible to operate four arms simultaneously while the upper and lower shoulder sections rotate independently of each other on a single shared waist section (40).

[0059] However, since the double-slope mounting surface creates a posture where the base of each arm is spread out to the side, it entails transportation constraints in which the width of the equipment is likely to exceed the inner width of a standard container (approx. 2.3m). In the present invention, the configuration in which a folding actuator (20) is placed at the joint of the base of each arm to switch between the working posture and the transport posture is intended to resolve these transportation constraints of the double slope. That is, the double-slope mounting surface (concentration of the working area at the front) and the joint folding (securing the transport width) are a configuration combined in a mutually complementary manner.

[0060] As a preferred example of the above-mentioned inclination angle, the primary forward inclination may be set to approximately 20° and the secondary lateral inclination to approximately 45°. The lateral inclination of approximately 45° is a compromise value that balances the distribution of gravity of the joint rotation plane (the aforementioned semi-SCARA configuration) and the securing of the arm's range of motion, and the forward inclination of approximately 20° is a value derived through verification of the actual design, which is a forward inclination level that can substantially eliminate the convergence area of ​​the rear while avoiding interference with the slider frame (53) and the control tower (70) at the rear of the upper arm. However, the present invention is not limited to these numerical values.

[0061] Both the main arm (50) and the auxiliary arm (60) may be composed of 6-axis multi-joint arms, and the reach of the auxiliary arm (60) is formed to be shorter than the reach of the main arm (50). The reach of the main arm may be determined by the length of the member that can be stored in a standard container when folded and the stability condition for forward tilting (e.g., reach within about twice the distance from the center axis (O) of the shared waist part to the rear support point (12c). Since the reach of the auxiliary arm is constrained by the ground height of the lower shoulder part (44) and ground interference during elbow bending, in one embodiment, the reach of the auxiliary arm may be set to about 40% to 70% of the main arm. The main arm (50) performs main processes such as 3DP output, masonry stacking, rebar insertion, concrete pouring, and window lifting using a large reach length, and the auxiliary arm (60) performs auxiliary and finishing processes that follow the main processes such as wall surface treatment, masonry joint finishing, and window installation drill fastening.

[0062] The fact that the reach and size of the auxiliary arm are set smaller than those of the main arm is intended not only to meet the requirements for work division but also to avoid interference constraints with outriggers and the ground in the lower space. For the same reason, the sequence of operations during folding is also performed separately from the upper main arm.

[0063] Referring to FIG. 6, the unit arm includes a first joint (J1) rotation base (51), a second joint (J2) hinge (52), a third joint (J3) hinge (55), wrist joint portions (56, 57, 58) of the fourth joint (J4) to the sixth joint (J6), and a grip head (59) at the end. The second joint (J2) and the third joint (J3) are linearly driven by a reversing slider-crank mechanism (53), which reciprocates the slider by means of a servo motor, a reduction gear, and a feed screw, and the linear motion of the slider is converted into rotational motion of the joints through the upper arm crank (63) and the forearm crank (64). The feed screw (65) and the upper arm motor (66) and forearm motor (67) that drive it are placed in close contact with each member of the upper arm (61) and forearm (62). With this configuration, large joint torque can be obtained without directly connecting a large reduction gear to the joint.

[0064] The above-described drive mechanism is a known mechanism of the same type as the reversing slider-crank mechanism employed in the boom drive of a hydraulic excavator in terms of kinematics. The configuration in which a linearly driven slider drives a remote member through a link is also widely used in linear delta type 3D printers (see Patent Document 18, Non-Patent Documents 9 and 10) in which a carriage driven linearly along a vertical column drives an end through a rod. In this embodiment, the drive source is replaced with an electric linear drive mechanism consisting of a servo motor, a reduction gear, and a feed screw instead of a hydraulic cylinder to ensure precise position control and self-holding characteristics. Furthermore, this embodiment is distinguished from conventional gravity compensation mechanisms that require a separate linkage or drive source for the counterweight in that the slider frame itself serves as a moving carrier for the counterweight.

[0065] In addition, the inversion slider-crank mechanism of the present embodiment has an arrangement in which the feed screw, drive motor, and reduction gear are aligned in parallel and in close contact with the side of the member along the longitudinal direction of the upper arm member. Accordingly, unlike conventional arrangements in which the drive unit, such as a hydraulic cylinder or electric cylinder, protrudes significantly outward from the arm, the entire drive system is accommodated in close proximity to the cross-sectional contour of the arm member, thereby preventing interference during folding storage, increasing the margin for collision with surrounding structures during operation, and allowing the entire stroke of the slider to be utilized as the movement path of the counterweight.

[0066] Meanwhile, the inverted slider-crank mechanism for upper arm drive requires the slider frame supporting the feed screw to extend to the rear of the upper arm; thus, this configuration is difficult to adopt in small robots designed for confined indoor spaces. However, in outdoor long-reach equipment, this rear extension frame is utilized as a moving carrier for the counterweight, and since collisions between the rear extensions and with the upper structure are avoided by setting the inclination angle of the aforementioned shoulder mounting surface, the disadvantages of indoor use are transformed into static advantages in large-scale long-reach applications. In other words, the inclined mounting surface and the slider-linked counterweight of the present invention are configured to be interdependent for long-reach applications.

[0067] Furthermore, while the effective stroke of an electric cylinder is limited relative to the actuator's total length due to the overlapping section between the cylinder tube and the piston rod, the inversion slider-crank mechanism of this embodiment utilizes most of the feed screw's total length as a stroke, thereby obtaining a larger joint range of motion within the same total length. In addition, since major drive components such as the motor and reduction gear are fixedly supported on the upper arm member and there are no rod-type members protruding outward, end-operational impacts are not directly transmitted to the drive components, thereby improving durability and safety.

[0068] To eliminate backlash in the joint drive system, a known anti-backlash double gear (dual pulley) structure (Patent Document 6) may be employed for power transmission in the third and fourth joints. The sixth joint may be driven by a conventional planetary reduction gear. As such, the drive mechanism of each joint is composed of known elemental technologies, and the feature of the present invention lies in the overall arrangement structure in which these known elements are combined.

[0069] A movable counterweight (54) is installed in conjunction with the slider frame of the inversion slider-crank mechanism (53) that extends to the rear of the upper arm. The counterweight (54) moves back and forth in conjunction with the position of the slider, that is, the change in the posture of the arm, thereby offsetting the movement of the center of gravity of the entire arm. Accordingly, the joint drive motor bears only the dynamic torque during acceleration and deceleration, and the holding torque in a stationary state practically converges to zero. This is the core mechanical structure of the present invention that prevents the self-multiplication of the driving unit weight that occurs when the long-reach arm is enlarged.

[0070] The upper and forearm members of the main arm (50) can be formed as a single rigid member that does not include an internal extension mechanism. A single rigid member has no sliding friction surface compared to an extension boom, allowing for lubrication-free operation, and has a simple sagging behavior, which increases the prediction accuracy of the coordinate system correction described later.

[0071] Referring to FIG. 8, a folding actuator (20) is provided at the base joint of each arm. The folding actuator (20) may include a hydraulic cylinder (20b) for arm folding, a hydraulic cylinder (20a) for waist folding, and an outrigger hydraulic cylinder (20c), and is operated by an electric hydraulic pump (not shown), and during transport, the four arms are folded in the longitudinal direction of the vehicle body (10) and stored on the upper part of the vehicle body. In the folded state, the entire equipment can be stored within the transport dimensions of a standard 40-foot container. After unfolding, the main structural parts are rigidly connected by the fastening of structural fastening parts (21), namely the waist folding fixing bolt (21a), the arm folding fixing bolt (21b), and the outrigger fixing bolt (21c), and lifting means such as a cargo loading fixing hook (15) may be provided.

[0072] Folding can be performed in the following order. First, the upper shoulder portion (41) rotates 180° so that the upper main arms are positioned facing the rear. In this state, when viewing the equipment from the side, the front-protruding pyramid arrangement is converted into a parallelogram arrangement, allowing the upper arms to be lifted to the rear and the lower arms to the front, respectively. First, each arm is aligned with a preset unique joint angle value so that they do not overlap each other when folding. Second, after the structural connection part (21b) between the first joint rotation base (51) of the upper arm and the inversion slider-crank frame (53) of the upper arm is released, the upper arms are folded toward the vehicle body by the hydraulic cylinder (20b) for arm folding, and at this time, the 3DP heads (37) of the extension stand (31) for the upper arms are also laid down around the extension folding hinge (38) and stored toward the main body. In the third step, with the waist folding fixing bolt (21a) released, the shared waist portion (40) is tilted toward the vehicle body by the waist folding hydraulic cylinder (20a). In the fourth step, the lower auxiliary arms are aligned in the same manner, that is, by a preset alignment angle value, and then stored through release and hydraulic folding. In the fifth step, after the outrigger fixing bolt (21c) is released, the outrigger (12) is folded by the outrigger hydraulic cylinder (20c).

[0073] By this multi-stage folding, the entire long-reach four-arm equipment is stored within the limited cross-section of a standard container. Transporting and storing the long-reach arm is a significant design challenge in itself due to the length of the member and the slider frame extending to the rear of the upper arm, and a combination of a preset alignment angle, a releaseable structural connection, and multi-stage hydraulic folding serves as the solution. Meanwhile, the hydraulic system can also be used for self-propelled driving of the vehicle body by sharing an electric hydraulic pump (21).

[0074] The driving motors of the upper and lower shoulder rotation parts (42, 45) are based on brake-embedded motors that maintain the posture when the power is cut off. Furthermore, if a worm gear type reduction mechanism with self-locking characteristics that prevent reverse driving is adopted as a reduction mechanism, the posture of the shoulder part and the arm can be mechanically maintained without a separate brake. This is an intrinsically safe structure required at outdoor construction sites.

[0075] Referring to FIG. 3, a plurality of material storage tanks (30: 30A, 30B) are arranged at the rear of the vehicle body (10). For example, the first storage tank (30A) can store polymer-based materials, and the second storage tank (30B) can store pellet-type mortar materials. The material storage tanks (30) are arranged at the rear of the vehicle body and serve as counterweights during front work. The vehicle body (10) may also be equipped with a mixing water tank (33) and a washing water tank (34).

[0076] On the vehicle body (10), an extension stand (31) for an upper arm that mounts a plurality of 3DP heads (37) and an automatic cleaning unit may be provided. The 3DP heads (37) are not permanently mounted parts but are operated as extensions (tools) that are selectively gripped by the grip head (59) at the end of the arm. The grip head (59) is equipped with a V-groove jaw so that a single jaw can be used for gripping 3DP heads, gripping rebar, and gripping bricks. An extension stand (32) for a lower arm for a lower auxiliary arm may be placed on the side of the vehicle body.

[0077] As a principle for the placement of extensions and materials, the extension stand (31) for the upper arm, the extension stand (32) for the lower arm, and the material storage container (30) are placed at the rear and side of the vehicle body so as not to interfere with the front workspace, and each arm can access them without interrupting work by rotating the shoulder part.

[0078] Four 3DP heads (37) can be mounted on the extension stand (31) for the upper arm. In one embodiment, one polymer discharge head that can be used continuously without cleaning and three cement-based discharge heads that require cleaning when use is discontinued are arranged at a distance that does not interfere with adjacent heads during the gripping operation of the grip head. Each mounted head is stored by a standing mechanism having an extension folding hinge (38) so that it is laid down toward the vehicle body during folding transport, and when working after unfolding, it stands upright and protrudes upward, thereby taking a position where the grip head of the upper main arm can easily grip it. The standing mechanism may be composed of a driving unit that rotates the stand around the extension folding hinge (38), and the driving may share the same electric driving hydraulic system as the folding actuator (20), and may automatically fold and stand up in conjunction with the folding sequence. However, the folding and standing configuration of such mounting heads is an auxiliary configuration adopted in conjunction with equipment folding for container storage, and may be omitted in equipment forms that do not require folding.

[0079] Assembly and finishing tools (36), such as a drill, trowel, and paint roller, which are used for gripping, are mounted on the lower arm extension stand (32) for the lower auxiliary arm. A maintenance opening (35) into which a grip head can be inserted may be formed between the tool stands. A mixing water tank (33) and a washing water tank (34) are arranged adjacently on the side of the lower arm extension stand (32).

[0080] As the opening and closing mechanism of the grip head, a known gear-synchronous gripper structure (see Patent Document 17) may be employed, in which the output pinion of a worm reducer drives a pair of mutually meshed sector gears, and each sector gear symmetrically opens and closes the jaws through a four-bar link. Due to the self-locking characteristics of the worm reducer, the gripping state is mechanically maintained even when the power is cut off, which is consistent with the self-locking design concept of the equipment.

[0081] The equipment may be operated in combination with the applicant's prior art. Regarding extensions and materials, 3D printing materials for construction (applicant's Korean Patent Application No. 10-2026-0030174), a washable discharge head (No. 10-2026-0030184), and a slab construction method (No. 10-2026-0084929) are combined. In particular, the material and head technology, which does not require hose cleaning when discharge is stopped, serves as a prerequisite for the present invention, which operates the 3DP head as a gripping extension (tool) rather than as a permanently mounted part. Meanwhile, regarding the triangular arrangement configuration of the equipment, the applicant's prior art application No. 10-2026-0007769 may be referenced.

[0082] The sensor configuration is described. A dedicated control sensor unit (71, 72) is fixedly positioned on the upper shoulder portion (41) and the lower shoulder portion (44), respectively, and each control sensor unit may include a dual camera (71a, 72a) and a LiDAR (71b, 72b). The control sensors are fixedly mounted based on the shoulder portions, so a separate head rotation mechanism is not used. An RTK GPS receiver (73) may be provided for measuring the external absolute position of the equipment. Additionally, an articulation camera (75) is positioned on the middle joint portion of the arm, and an end-of-hand camera (76) is positioned on the wrist end portion, providing a viewpoint for observing the forearm and end-of-hand from the joint portion and a viewpoint for close observation of the work object, respectively. Automatic level sensors (77) may be positioned at a total of five locations, including one location for measuring the verticality of the column in front of the upper shoulder portion (41), and four locations on the grounding portions on the left and right of the outrigger and above them. Furthermore, a plurality of measurement sensor units, such as strain gauges and IMUs, may be mounted on the surface of the arm member or the joint connection to measure load, deflection, vibration, or strain in real time.

[0083] The upper control sensor unit (71) can be installed on the top of the control tower (70), which is fixed to the upper shoulder unit (41) and rotates together with the shoulder unit. The control tower (70) is extended to be higher than the total height of the work area, for example, about 10% higher, so as to be able to view the total height of the work area from above. Two cameras facing the work direction, one rear camera (71c) facing the rear, and a LiDAR facing the work direction are installed on the top, and a work light (74) can be installed on the bottom. The control tower (70) is erected in the space between the center of the upper shoulder unit, that is, between the slider frames (53) and counterweights (54) of the left and right main arms, so that they do not interfere with each other from the rear. The fact that such an arrangement is established itself demonstrates that a collision-free gap between the rear protrusions is structurally secured. Furthermore, the two cameras facing the work direction are positioned as far apart as possible to the left and right within this secured gap, thereby maximizing the baseline length of the stereo vision and improving the depth measurement precision in the remote work area. A lower control sensor unit (72) having a camera, lidar, and lighting of the same configuration is also separately installed on the lower shoulder unit (44). Accordingly, the upper arms and lower arms can be operated as two independent dual-arm robots, each having its own control sensor system.

[0084] Furthermore, the following sensor mounting structure may be adopted as an interface for collecting measurement data for future learning-based control. Each joint is equipped with an absolute encoder on the deceleration output side, i.e., a joint angle sensor (68), separately from the motor-side encoder, to measure the actual joint angle, including backlash of the deceleration system and member deflection. An inertial measurement unit (IMU) and a strain gauge are mounted on the upper and forearm members and the shoulder part to measure vibration, deflection, and strain of the member. A force sensor for measuring gripping force or contact force may be mounted on the wrist part or grip head. A load sensor (load cell) is mounted on the material storage container (30) to measure changes in the rear load due to material depletion, i.e., fluctuations in the counterweight effect. Wind speed and ambient temperature sensors for responding to outdoor environments may be mounted on the top of the control tower (70). The measurement data from these sensors can be used as input data for correcting the equipment's coordinate system and for subsequent control models.

[0085] The measurement elements themselves, such as the dual encoder, strain gauge, inertial measuring device, force sensor, and load sensor, are individually known (see Patent Documents 15 and 16, and Non-Patent Documents 3 and 4), and the present invention provides a mounting position and arrangement structure that aligns with the structure of the 4-arm long reach equipment for these known measurement elements.

[0086] The control unit (78) corrects (calibrates) the position error between the initial driving coordinate system of the equipment and the arm end based on data measured from the horizontal level sensor (13, 77), control sensor unit (71, 72), joint and end camera (75, 76). Accordingly, end errors caused by sagging of the lightweight member, assembly tolerances, temperature deformation, etc. are absorbed, thereby ensuring construction precision within the construction tolerance.

[0087] Each driving unit of the present invention can be controlled by a conventional MCU, PLC, or artificial intelligence (AI) control module. In addition, visual information, spatial information, and structural behavior data collected from the control sensor unit, end camera, and measurement sensor unit can function as a multimodal input data collection interface for a learning-based control model, such as a Vision-Language-Action (VLA) model linked with 3D spatial information around the robot and work instruction commands.

[0088] The multi-arm cooperative control, motion planning, and collision avoidance for the four arms of the equipment are at a level that can be implemented without excessive experimentation by a person skilled in the art to which the present invention belongs, by using conventional multi-joint robot control technology provided in known robot operating systems and physical simulation environments (e.g., ROS2, NVIDIA Isaac Sim, etc.).

[0089] A modified embodiment is described. First, a configuration may be adopted in which a lifting mast is interposed between the shared waist portion (40) and the vehicle body (10), allowing the entire shoulder portion to be raised and lowered in multiple discrete height steps. In this case, construction of multiple heights is possible with the same arm configuration. Second, a long-reach specification may be adopted in which the length of the main arm member is extended; in this case, the configuration of the inversion slider-crank mechanism, the interlocking counterweight, and the coordinate system correction is applied in the same way. Third, a two-arm specification in which the lower shoulder portion and auxiliary arm are omitted and only a pair of upper main arms are provided may also share the shoulder inclined mounting surface, inversion slider-crank, and counterweight configuration of the present invention.

[0090] The embodiments described above are merely examples, and those skilled in the art will understand that various modifications and equivalent implementations are possible within the scope of the technical spirit of the present invention. The scope of protection of the present invention shall be interpreted by the claims below. Explanation of the symbols

[0091] 1: 4-arm construction robot equipment 2: Mobile base section 3: Arm-driven robot section [Mobile Base Unit] 10: Chassis 11: Wheels 12: Outrigger (12a: Left, 12b: Right, 12c: Rear Center) 13: Horizontal level sensor 14: Leveling screw 15: Fixing hooks for cargo loading 20: Folding actuator (20a: Hydraulic cylinder for waist folding, 20b: Hydraulic cylinder for arm folding, 20c: Outrigger hydraulic cylinder) 21: Structural fastening part (21a: Waist folding fixing bolt, 21b: Arm folding fixing bolt, 21c: Outrigger fixing bolt) 30: Ingredient Bin (30A: Ingredient Bin A, 30B: Ingredient Bin B) 31: Extension stand for upper arm 32: Extension stand for lower arm 33: Mixing water tank 34: Washing water tank 35: Maintenance opening 36: Assembly tools 37: 3DP Head (37a: 3DP Head B1) 38: Extension folding hinge [Arm-driven Robot Department] 40: Shared waist 41: Upper shoulder 42: Upper shoulder rotation part 43: Upper arm mounting surface 44: Lower shoulder area 45: Lower shoulder rotation part 46: Lower arm mounting surface 47: Crossroller bearing 50: Main arm (50L: Upper left arm, 50R: Upper right arm) 51: J1 Rotating Base 52: J2 hinge 53: Upper arm slider frame (reverse slider-crank mechanism) 54: Movable counterweight 55: J3 hinge 56: J4 joint (56a: J4 motor) 57: J5 joint 58: J6 joint 59: Grip Head (Grasp Grip) 60: Auxiliary arm (60L: Lower left arm, 60R: Lower right arm) 61: Upper arm 62: Forearm 63: Upper arm crank 64: Forearm crank 65: Transfer screw 66: Upper arm motor 67: Forearm motor 68: Joint angle sensor 70: Control Tower 71: Upper control sensor unit (71a: Dual camera, 71b: LiDAR, 71c: Rear camera) 72: Lower control sensor unit (72a: Dual camera, 72b: LiDAR, 72c: Rear camera) 73: RTK GPS receiver 74: Lighting 75: Articulated Camera 76: End camera 77: Automatic Level Sensor 78: Control unit [sign] W: Construction work area M: Construction materials G: Center of gravity T: Triangular arrangement (support triangle) P: Front pyramid shape (virtual pyramid) C: Standard container specifications O: Column center F: Folding state (virtual line)

Claims

Claim 1 A four-arm robot for construction, comprising: a movable body; a shared waist portion erected on the body; an upper shoulder portion and a lower shoulder portion arranged vertically on the shared waist portion and each rotating independently through a rotational bearing; a pair of main arms having a first reach length, each being a multi-joint arm with six or more axes coupled to both sides of the upper shoulder portion; a pair of auxiliary arms having a second reach length shorter than the first reach length, each being a multi-joint arm with six or more axes coupled to both sides of the lower shoulder portion; and a grip head provided at the end of each of the main arms and auxiliary arms to grasp construction materials or work tools. Claim 2 A four-arm construction robot according to claim 1, wherein the arm mounting surfaces of the upper shoulder portion and the lower shoulder portion are each positioned on different inclined planes of a virtual pyramid with a vertex facing the front of the equipment, and are formed as inclined convergence surfaces that are inclined firstly forward and secondarily laterally, and the main arm is mounted to approach the workspace in an upward bending posture where the elbow joint is higher than the shoulder portion, and the auxiliary arm is mounted to approach the workspace in a downward bending posture where the elbow joint is lower than the shoulder portion, so that the convergence area of ​​both arms is concentrated in the workspace at the front of the equipment, thereby avoiding collision between the four arms. Claim 3 A four-arm robot for construction, comprising: a reversing slider-crank mechanism according to claim 1 or 2, wherein at least one of the pitch joints of each of the main arm and the auxiliary arm is linearly driven and the slider frame extends to the rear of the upper arm member; and a counterweight that moves in conjunction with the slider and offsets the shift of the center of gravity due to a change in the arm's posture. Claim 4 A four-arm construction robot according to claim 1, further comprising outriggers that are deployably installed on the vehicle body, wherein the outriggers are composed of three-point supports, consisting of two points on both front sides and one point in the rear center of the vehicle body, wherein the vertical extension amount of the two points on both front sides independently determines the lateral inclination of the equipment, and the vertical extension amount of the one point in the rear center independently determines the longitudinal inclination of the equipment, wherein the reference plane of the equipment is geometrically uniquely determined by the adjustment of the extension amount of the three points, and wherein the center of gravity of the equipment, including changes in posture during operation and gripping load, and the center axis of the shared waist portion are arranged to be located inside the support triangle formed by the three points. Claim 5 A four-arm construction robot equipment according to claim 3, further comprising: a folding actuator provided at the base joint of each of the main arm and the auxiliary arm; and a releaseable structural connection between the slider frame and the base joint, wherein, during transport, the four arms are folded in the longitudinal direction of the vehicle body by the folding actuator while the structural connection is released, so that the entire equipment is stored within the standard container transport dimensions. Claim 6 A four-arm robot for construction according to claim 1, further comprising: a control sensor unit fixedly disposed on the upper shoulder portion and the lower shoulder portion and including a camera and a lidar; a camera disposed on the joint portion or end portion of the arm; a horizontal level sensor disposed on the vehicle body; and a control unit that corrects the initial driving coordinate system of the equipment and the static position error of the end portion of the arm based on data measured from the control sensor unit, the camera and the horizontal level sensor.

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