594 results about "Ground support" patented technology

The invention relates to an autonomous navigation method for lunar satellite formation and a second-order filtering navigation architecture, and the autonomous navigation method comprises the steps: obtaining orbit prediction information based on a kinetic model of the lunar satellite formation, and obtaining collaborative theory observation information based on a collaborative observation model, carrying out fusion processing on orbit prediction information, collaborative theory observation information and multi-source observation data of in-orbit observation by using an extended Kalman filtering algorithm, and estimating an absolute orbit state of the lunar satellite formation; establishing a relative motion model of the slave satellite under the local coordinate system of the master satellite, and establishing a relative measurement model; and taking the absolute orbit state of the master satellite as a reference datum, obtaining a preliminary prediction relative orbit state based on the relative motion model of the slave satellite, and obtaining relative measurement data including distance measurement and angle measurement based on the relative measurement model, and fusing the relative measurement data and the preliminarily predicted relative orbit state through an extended Kalman filtering algorithm to estimate the relative orbit state of the slave satellite. Navigation may be independent of ground support.

The invention provides an airport parking space allocation method and system based on gridding space-time layering, and the method comprises the steps: building an airport space-time grid model through obtaining and space-time correlation analysis of multi-source basic data, such as real-time flight dynamic data, parking space physical attributes, historical operation efficiency and ground guarantee resource states; then, on the basis of multi-level feature constraint fusion, adaptive weight dynamic adjustment and sparse constraint low-dimensional reconstruction, adaptive optimization facing complex space-time requirements and delay disturbance is achieved, and an airport parking space distribution matrix is obtained; generating an anti-conflict camera configuration set in combination with dynamic coupling and conflict verification of ground support resources; and finally, through physical constraint real-time inspection and historical efficiency mode matching, generating an optimal distribution matrix of the airports, so that the overall use efficiency and the operation guarantee capability of airport airport resources are remarkably improved, and the airport operation efficiency and the service quality are improved.

The invention discloses a civil aviation airport ground guarantee resource scheduling method and device and a medium, and relates to the technical field of artificial intelligence, and the method comprises the steps: obtaining a real-time flight plan, and constructing a guarantee resource coupling network based on the real-time flight plan and a predefined guarantee flow rule base; performing conflict prediction and conflict influence analysis on the guarantee work of the future flight by traversing the guarantee resource coupling network, and generating a structured conflict early warning report; triggering an on-demand scheduling mechanism of a virtual resource pool for querying and allocating available resources on demand according to the structured conflict early warning report, querying available shared guarantee resources in the virtual resource pool, and generating a conflict resolution scheme which can be directly executed; and executing the conflict resolution scheme, monitoring an execution result through the Internet of Things data, feeding back the execution result to the guarantee resource coupling network, and calibrating a duration parameter in the guarantee resource coupling network. Through the constructed support resource coupling network, the prospective performance and the cooperative robustness of ground support scheduling are improved.

The invention relates to the technical field of conflict detection, in particular to an airport support vehicle conflict diagnosis method based on digital twin driving. Comprising the following steps: acquiring attribute information of an airport object, and generating a corresponding digital twin monomer in a twin space; associating the digital twin monomers according to the service logic to form a flight ground support twin service; identifying guarantee conflicts, acquiring conflict occurrence time, places and reasons, and performing conflict analysis; adjusting the guarantee plan, and performing simulation deduction; through the implementation of the mode, a guarantee service process with real-time data interaction is provided, the number of guarantee service conflicts is reduced, and the dynamic adjustment capability of a scheduling plan is improved.

The invention relates to an automatic order dispatching method based on civil aviation airport aircraft ground support, which adopts a dynamic causal relationship identification module based on a Bayesian network, and combines a context awareness module of a convolutional neural network (CNN) and a long short-term memory (LSTM) network to improve prediction accuracy and task allocation efficiency. An improved multi-objective optimization algorithm is combined with a genetic algorithm and a particle swarm optimization algorithm, and a dynamic weight adjustment mechanism is introduced, so that self-adaptive optimization configuration of resources is realized. A path planning algorithm combining multi-level A * search and deep reinforcement learning can adjust a path in real time and dynamically avoid obstacles, and the system enhances real-time response capability and decision accuracy through a self-learning algorithm based on a depth deterministic policy gradient (DDPG) and a comprehensive decision support system based on a graph neural network (GNN). According to the method, the operation efficiency, the safety and the emergency response capability of the airport ground guarantee service are improved.

The invention discloses an airport ground guarantee work key time node automatic identification method and device, and relates to the technical field of image processing, and the method comprises the steps: inputting each airport scene image in an airport scene monitoring video into a trained target detection model, obtaining category information and position information of behavior subjects in each airport scene image; by using a target tracking model, according to category information and position information of key time node behavior subjects in all airport scene images, determining space-time motion information and confidence of each behavior subject in the airport scene monitoring video; and inputting the category information, the space-time motion information and the confidence coefficient of each behavior subject in the airport scene monitoring video into a trained dynamic graph attention model to obtain an identification result of the airport scene ground support work key time node. According to the invention, the accuracy and efficiency of important ground guarantee working time node identification in the airport scene image are improved.

A truck bed mounted carrier system includes a frame assembly installable in a truck bed with lateral supports and outer main supports, inner supports that slide within the outer main supports, a center outer support, and a second inner support that slides within the center outer support. A carrier frame coupled to the frame assembly extends from and retracts into the truck bed, supported by radius supports that provide structural integrity when extended. The system features a pulley assist mechanism with gas springs that creates a counterbalance force, a mechanical drive assembly with sprocket and roller chain for movement control, and deployable transport stands for ground support during loading operations. Adjustable bed rail struts with locking mechanisms secure the system to the truck bed without permanent modification. Low-friction materials and strategically positioned slides ensure smooth operation throughout the extension and retraction cycles.

A free-standing accessory stand that includes a ground support portion and an enclosure is provided. The enclosure is disposed about a central axis of the accessory stand. The upper surface faces away from the ground support. The accessory stand includes a retractable accessory support that has an outer surface projecting away from the enclosure in a first configuration. A mounting space is provided along the outer surface of the retractable accessory support above the upper surface of the enclosure. The outer surface is retracted in a second configuration.

The invention relates to the technical field of surveying and mapping equipment, and discloses a surveying and mapping instrument with soft and hard ground switching dual-mode supporting legs, the surveying and mapping instrument comprises a debugging platform and a surveying and mapping instrument body, and a multi-stage horizontal adjusting assembly for rapidly adjusting and leveling the surveying and mapping instrument body is arranged between the debugging platform and the surveying and mapping instrument body. The bottom of the debugging platform is provided with at least three sets of supporting leg assemblies, and the bottoms of the supporting leg assemblies are detachably provided with switching discs through separation assemblies. The first soft ground supporting assembly and the second soft ground supporting assembly are adopted to be used according to different soft ground conditions, short-term effective supporting of the tripod is achieved, rapid installation of the switching disc and positioning of the hard ground supporting assembly, the first soft ground supporting assembly and the second soft ground supporting assembly are achieved through the separation assembly, and therefore the switching disc can be conveniently and rapidly installed. And for different use environments, adjustment is carried out when the switching disc is installed, and the operation is simple and convenient.

The invention provides a wheel-paddle integrated multi-mode land-air amphibious transformation robot, and relates to the technical field of aerial robots, the robot comprises a robot main body, and the robot main body is used for controlling the robot to realize land-air amphibious transformation, air flight and land walking; the wheel-paddle integrated mechanism is formed by combining two parts, namely a land walking mechanism and an air flying mechanism; the mechanical arms are connected to the four corners of the robot body, and the other ends of the mechanical arms are connected with the wheel-paddle integrated mechanism through servo push rod mechanisms. The deformation mechanism adopts a bistable locking mechanism driven by a servo electric push rod, a stable mechanical self-locking mechanism is constructed while the axial thrust of the push rod is kept, conversion between a flight folding state and a ground supporting state can be completed only through instantaneous driving, the wheel-propeller integrated mechanism adopts a propeller and protective driving wheel composite structure design, and the structure is simple and convenient. And a power decoupling system of the non-rotating core module and the rotating execution mechanism is constructed.

The invention relates to the technical field of airport resource management, in particular to an airport ground support resource dynamic optimization method and system based on digital twinning, and the method comprises the steps: analyzing an airport business process knowledge graph, and fusing multi-modal data to construct a generative digital twinning model; performing multi-scene simulation deduction and multi-target optimization based on the generative digital twin model to generate a long-term planning scheme; during the execution period of the long-term planning scheme, monitoring the deviation between the actual operation data and the scheme predicted value, and performing dynamic adaptive adjustment on the long-term planning scheme; and combining a long-term planning scheme with real-time operation data to provide decision support, evaluating an optimization effect, and taking an evaluation result as feedback to iteratively optimize the generative digital twinborn model. According to the method, the generation type digital twinborn model is constructed, and a double-layer closed-loop optimization mechanism of long-term planning and short-term correction is established, so that the overall efficiency and punctuality rate of airport ground guarantee and the toughness of coping with emergencies can be effectively improved.

The present invention provides a broadband filtering unit, which includes a grounding support base, a feeding balun, and a square radiation surface. Both the front and back surfaces of the square radiation surface are copper-clad. Among them, the shape of the copper cladding on the front is similar to four combined square structures. Two square structures located on the diagonal form two oscillator arms in one polarization direction. The middle positions of each oscillator arm are all hollowed out. The oscillator arm is composed of multiple cascaded LC circuits. Multiple open-circuit filtering stub segments are also arranged on the oscillator arm. The present invention is used in a multi-frequency and multi-array combined antenna, which can well avoid interference with adjacent arrays. Its special multiple filtering structure can adapt to various irregular arrays, effectively reduce the size of the antenna, improve the performance of the antenna interleaved array, and has a simple structure, convenient installation, and low cost. At the same time, by adjusting the positions of the LC circuits and the lengths of the filtering stub segments on the unit radiation surface, the expansion of different frequency bands and the filtering of different frequency bands can be achieved.

The invention relates to the technical field of photovoltaic supports, in particular to a flexible photovoltaic support. According to the technical scheme, the inclination adjusting assembly comprises a wind receiving plate, a torque spring, a circular plate, a blocking piece and a supporting plate, the supporting plate is fixedly installed at the top of a floor supporting frame, the side portion of the supporting plate is rotationally connected with the circular plate, and the torque spring is fixedly installed on the side, away from the supporting plate, of the circular plate; the other end of the torque spring is fixedly connected with the wind receiving plate, and a blocking piece is arranged at the position, located on the same side with the circular plate, of the side portion of the supporting plate. The wind receiving plate and the photovoltaic panel group are jointly acted by wind power, when the wind power is too large, the rotating force applied to the circular plate by the wind receiving plate through the torque spring is larger than the resistance of the clamping block, at the moment, the circular plate rotates, the inclination angle of the photovoltaic panel is adjusted, and the photovoltaic panel is prevented from being fractured due to the too large wind power.

The invention discloses a rapid connection testing device for a printed circuit assembly board, and aims to solve the problems of high cost, low connection density, large occupied space, tedious operation and the like in the existing testing technology. The device comprises a quick-connection probe module, a positioning tray and a pull pin, the quick-connection probe module comprises a quick-connection probe seat module, a protective cover module and a spring, positioning and locking are realized by multiplexing existing mounting holes of a to-be-tested PCB, electrical connection is realized by utilizing contact of a spring probe and a test point, a quick-connection positioning guide sleeve, a lock bead and a quick-connection ring are combined to form a quick locking / unlocking structure, and the quick-connection probe seat module and the protective cover module are connected with the pull pin. The conductive bushing and the grounding support ring form a grounding loop in cooperation with auxiliary positioning of the guide pin. A special test connector is omitted, so that the material cost is reduced; the connection density and the signal rate are improved, and the PCB space is saved; the operation efficiency is improved through the quick connection structure, and the device is suitable for efficient mass production testing.

The invention relates to the field of superconducting Tokamak devices, and discloses a support structure of a correction field superconducting coil and a superconducting Tokamak device with the same, the support structure comprises a first support assembly, the first support assembly is arranged on a longitudinal field coil and is used for supporting an upper arc section of the correction field superconducting coil; the second supporting assembly is fixed to the ground supporting structure of the longitudinal field coil and used for supporting the lower arc-shaped section of the correction field superconducting coil; the vertical supporting assembly is located between the first supporting assembly and the second supporting assembly in the vertical direction and used for fixing the two vertical extending sections in the two sets of adjacent correction field superconducting coils; the cooling assembly comprises a first cooling part used for exchanging heat with the first supporting assembly and a second cooling part used for exchanging heat with the second supporting assembly. Therefore, the overall heat balance of the superconducting Tokamak device can be realized, and the position precision and the working efficiency of the superconducting coil in the correction field can be effectively improved.

A system for installing a novel engine shield in the opening of an aircraft engine that is too high off the ground to be accessed by the ground support technicians while standing on the ground that includes a housing of the shield that has a front section that extends away and downward from a rear section of the housing. The front section of the housing contains an installation pole port assembly that includes an opening or port in a structure that is operably connected to a drive screw via a universal joint. In some embodiments, the installation pole port assembly is positioned to be recessed within an opening in the front section of the housing. Other versions also include a photoluminescent material applied near or around the opening in the front section of the housing.

The invention provides a fire-fighting box mounting, fixing and supporting base, and belongs to the technical field of building construction. The fire-fighting box mounting, fixing and supporting base comprises a supporting assembly and a bearing assembly, the bearing assembly comprises a bearing plate, an adjusting limiting device, a bubble level and a fire-fighting box body, a supporting piece, a threaded column, an inner threaded cylinder, an outer ring and a sliding block are arranged, the supporting piece is in contact with the ground to support the whole, and the inner threaded cylinder is driven to rotate by rotating the outer ring; through the design of the two independent threaded columns and the bearing plate rotationally connected, the height can be adjusted, the inclination degree of the bearing plate can be adjusted, the fire box body is supported at the installation position, the levelness and perpendicularity of the fire box body are guaranteed, then the fire box body is installed through bolts, and the fire box is good in forming effect after installation is completed; the fire-fighting box body is more convenient to install, the fire-fighting box body can be placed through adjustment limiting, and the fire-fighting box body can be adjusted to be suitable for various types of fire-fighting box bodies.

The invention discloses bridge floor self-moving installation equipment and method for a prefabricated guardrail wall of a subway viaduct. The equipment comprises a base, a supporting displacement mechanism, a vertical supporting rod mechanism, an operation platform, a balance weight mechanism, a hoisting mechanism and a detection assembly. The supporting displacement mechanism comprises a wheel set and an oil cylinder supporting leg which are used for overall displacement and ground supporting respectively. The vertical supporting rod mechanism is fixedly arranged on the top of the base and used for supporting the operation platform. The counterweight machine is arranged on the base, so that the equipment is prevented from overturning; the hoisting mechanism comprises a moving trolley, a longitudinal driving assembly and a winch; the detection assembly detects related installation information; according to the installation equipment, an integrated installation system with a hoisting function is formed through the bridge floor self-moving base, the hoisting mechanism capable of being adjusted in a three-dimensional mode and the matched vertical supporting rod and counterweight system, dependence on large ground hoisting machinery is not needed, and the problems that in traditional hoisting operation, traffic limitation is serious, and efficiency is low are effectively solved; and meanwhile, precise positioning and mounting of the prefabricated guardrail wall are achieved.

Systems, devices, and methods for a ground support system for an unmanned aerial vehicle (UAV) including: at least one handling fixture, where each handling fixture is configured to support at least one wing panel of the UAV; and at least one dolly, where each dolly is configured to receive at least one landing pod of the UAV, and where each landing pod supports at least one wing panel of the UAV; where the at least one handling fixture and the at least one dolly are configured to move and rotate two or more wing panels to align the two or more wing panels with each other for assembly of the UAV; and where the at least one dolly further allows for transportation of the UAV over uneven terrain.

The utility model provides a chemical raw material storage device convenient to transfer, and relates to the field of chemical equipment. The chemical raw material storage device convenient to transfer comprises a storage barrel, a moving seat used for assisting displacement is arranged at the bottom of the storage barrel, a grounding supporting mechanism used for abutting against the ground is connected to the bottom side of the storage barrel in a sleeving mode, and the grounding supporting mechanism comprises a grounding supporting seat and limiting supporting pieces arranged on the two sides of the storage barrel. According to the chemical raw material storage device convenient to transfer, through cooperative use of the storage barrel bottom moving seat and the grounding supporting mechanism, namely, through upward displacement adjustment of the storage barrel bottom grounding supporting mechanism, a worker can conveniently transfer the chemical raw materials under the condition that the whole storage device stored with the chemical raw materials does not need to be lifted up; and the movable seat is exposed at the bottom of the storage barrel for use, so that the storage barrel is assisted in short-distance displacement, the overall operation is safe and labor-saving, and the safety and convenience of the device in use are improved.

A method for determining a tractor longitudinal force threshold value for a tractor longitudinal retardation force that can be imparted on a tractor of a vehicle combination including the tractor and a trailer for retarding the vehicle combination, the tractor including a set of tractor wheels adapted to engage the ground supporting the tractor, each wheel of the set of set of tractor wheels including a tire,the method including:determining a tractor lateral force value,determining a tractor tire lateral force limit value using a tire model for determining a tire lateral force limit;determining a reference lateral force value using said tractor lateral force value and the tractor tire lateral force limit value;determining a horizontal friction force value, anddetermining the tractor longitudinal force threshold value.

The invention discloses an expansion multiplexing type satellite ground support system and a working method. The method comprises the following steps: S1, the satellite ground support system accepts a work task demand; s2, analyzing and planning a specific task to form a specific task plan; s3, according to the task plan, realizing deduction of a task plan scheme through simulation of an environment situation and a satellite flight situation; s4, generating a control instruction for the satellite, and verifying the control instruction; s5, sending the verified control instruction to a ground measurement and control system, and uploading the instruction by the ground measurement and control system; and S6, performing real-time monitoring and evaluation on a satellite task execution process, and performing alarm processing on abnormal conditions in the task execution process. The method can be expanded and reused for ground support of multi-model new technology test series satellite platforms, can continuously expand the computing power according to requirements, and provides a simulation verification platform for new technology test verification.

The invention discloses a photovoltaic panel inclination angle adjustable supporting device used in a strong wind environment. The photovoltaic panel inclination angle adjustable supporting device comprises an inclined support, a ground fixing support, a lifting module, a rib plate, a rope pulling device and a control module. The ground fixing support is used for being fixed on the ground, and the inclined support is used for installing and fixing a photovoltaic panel. The inclined support is rotatably connected with the ground fixing support, and a second guide rail structure is arranged on the side edge of the inclined support; the wheel disc structure of the lifting module slides along the second guide rail structure and is used for adjusting the included angle between the inclined support and the ground fixing support. A mechanical redundancy protection mechanism is constructed through mechanical gravity self-locking, it is ensured that when electronic equipment fails, the safe state of the photovoltaic panel is still maintained, meanwhile, it is avoided that an execution mechanism needs to additionally input energy to maintain the inclined state of the photovoltaic panel, and the problem that the photovoltaic panel is damaged by wind in the strong wind environment can be solved with low cost and low energy consumption.

The utility model discloses a combined device supported by a unilateral formwork, which comprises a unilateral formwork system, a unilateral support system, an embedded part system and a support system, the unilateral support system is provided with an embedded part limiting support, and the embedded part system comprises a ground embedded rod, a connecting nut, an external connecting limiting rod, beam pressing section steel and a fixing part. The pressing beam profile steel is located on the upper side of the embedded part limiting support, and the top end of the externally-connected limiting rod penetrates through a reserved seam between the two pieces of pressing beam profile steel and is anchored through a fixing part connected to the surfaces of the pressing beam profile steel in a pressed mode. The support system comprises a ground support rod, a horizontal support rod and a support vertical buried rod, the front end of the ground support rod is supported at the far end of the right triangle frame, the rear end of the ground support rod is supported at the front side of the horizontal support rod, and the bottom of the support vertical buried rod is buried in the ground. A force transmission system is clear, structural loads are transmitted through the reliable force transmission system through reasonable connection and anchoring, the forming effect is good, repeated turnover use can be achieved, erecting and disassembling are convenient and fast, and labor cost is saved.

The invention provides an unmarked kinetic analysis method and system for real-time tracking and shooting of an unmanned aerial vehicle, and the method comprises the steps: carrying out the flight control of the unmanned aerial vehicle, and obtaining the dynamic image data, tracked and shot by the unmanned aerial vehicle, of a sporter running on a playground curve or a curve path; synchronizing and preprocessing the dynamic image data recorded by different cameras; extracting 2D key points of a human body from the preprocessed image, and reconstructing a three-dimensional motion track of the human body in a local coordinate system of the camera; carrying out posture compensation on the three-dimensional motion trail, ensuring the consistency of human body joint point trails under a ground world reference system, carrying out human body model scaling and muscle model scaling calculation, and carrying out inverse kinematics analysis; according to the inverse kinematics data, the centripetal acceleration of the sporter in the curve motion is calculated; and performing inverse dynamics calculation based on the centripetal acceleration, and calculating the ground support force. According to the invention, unmarked dynamic analysis of real-time tracking shooting of the unmanned aerial vehicle can be carried out.

The invention discloses a quadruped robot supporting leg counter-acting force planning control method, which belongs to the technical field of robot control, and comprises the following steps: firstly, acquiring current gait information of a quadruped robot, and identifying a current supporting leg; secondly, constructing a ground support polygon model; then setting stable support constraint conditions based on a ground support polygon model, and calculating a current expected state of the mass center of the robot; constructing a virtual model of the quadruped robot, and calculating the reactive force of the current supporting legs of the quadruped robot; and finally, the output torque of each motion joint of the quadruped robot is calculated to generate a robot planning control instruction. A stable supporting constraint condition is formed by recognizing supporting legs of the quadruped robot and establishing a ground supporting polygon model, and the current reactive force of the supporting legs is calculated based on the stable supporting constraint condition, so that a robot planning control instruction is generated, planning control over the reactive force is achieved, and the gait stability of the robot is improved.

The invention belongs to the technical field of aircraft ground support facilities, and particularly relates to a fluid-solid coupling mechanical analysis method for a large-span aircraft ground agile protection structure. According to the method, on the basis of an arbitrary Lagrange-Euler (ALE) algorithm, by integrating HyperMesh pretreatment and an LS-DYNA solver, high-precision simulation of fluid-structure interaction response of the plane ground agile protection structure under the action of a wind load is achieved. Comprising the following steps: establishing an aircraft ground agile protection structure finite element model and carrying out component division and grid division; constructing a semi-cylindrical air drainage basin and setting fluid material attributes and boundary conditions; and defining a fluid-solid coupling interface, and carrying out explicit dynamic calculation by adopting a bidirectional coupling algorithm. According to the method, the problems of low simulation precision and poor convergence of a flexible large-span structure in a traditional method are effectively solved, the stress, deformation and stability of the plane ground agile protection structure at different wind speeds can be accurately evaluated, and a reliable basis is provided for wind resistance design and safety evaluation.

The utility model discloses an unmanned aerial vehicle undercarriage, and relates to the technical field of undercarriages. The device comprises a fixing plate and a mounting frame, the top of the mounting frame is fixed to the bottom of the fixing plate, an adjustable supporting assembly is rotatably mounted in the mounting frame, a buffer rod is fixedly mounted at the top of the fixing plate, a lifting plate is fixedly mounted at the top of the buffer rod, a groove is formed in the top of the lifting plate, and a rotary clamping assembly is fixedly mounted in the groove. The top of the lifting plate is provided with a buffer foam plate, and the bottom is fixed with a drawer. Through the adjustable supporting assembly, the ground supporting mode can be changed according to the actual use condition, the height of the base can be adjusted, the undercarriage can be conveniently used on the uneven ground, the stability is better, meanwhile, the unmanned aerial vehicle can be clamped and fixed through the rotary clamping assembly, and the unmanned aerial vehicle can be conveniently and rapidly fixed. And the protection plate can be rotated to protect the top of the unmanned aerial vehicle.

The invention discloses an automatic unfolding foundation pit side wall supporting structure which comprises a foundation pit ground supporting plate and a foundation pit side face overturning supporting plate hinged to the foundation pit ground supporting plate, and a hydraulic cylinder overturning driving mechanism is arranged between the foundation pit ground supporting plate and the foundation pit side face overturning supporting plate. A parallel overturning lower supporting assembly and a parallel overturning side supporting assembly are arranged on the two sides of the foundation pit ground supporting plate and the two sides of the foundation pit side face overturning supporting plate correspondingly, when the foundation pit supporting structure is installed, an oil cylinder is started, the foundation pit supporting structure can be automatically unfolded by 90 degrees, and in the unfolding process, the two face expanding supporting plates in the foundation pit supporting structure are automatically unfolded; the expansion supporting plates are arranged in the four positions and are finally flush with the main body plate, the supporting area is increased, the expansion supporting plates in the four positions are automatically folded during storage, the transverse occupied space in the transferring process is reduced, carrying is easier, the expansion supporting plates are turned over in parallel in the unfolding process, three supporting inclined rods are arranged for supporting after unfolding, and stability is improved.