Research And Design Of Automatic Lifting And Releasing Lifting Device For Reinforced Concrete Precast Members

Prefabricated concrete structure have received strong support in recent years because of their characteristics of meeting the requirements of green buildings,facilitating industrialized construction and information management,and develop rapidly.The realization of industrial construction is the core of improving the construction quality and efficiency for prefabricated buildings.Among them,by increasing the degree of mechanization and automation of prefabricated component operations at the construction site,such as handling and installation of prefabricated components,posture adjustment and seating of prefabricated components,joint casting between components,external wall surface treatment,etc,which is the key to achieved industrial construction.However,at present,during the construction of prefabricated buildings,lifting and installation of prefabricated components mainly adopts traditional lifting equipment and artificial auxiliary operations.The construction efficiency is low and the hidden danger of personnel safety is large.To this end,the government launched a National Key R&D Plan for key technologies and equipment for efficient hoisting and installation at the construction site.The aim is to develop key technologies and equipment for automatic picking and placing of prefabricated components,automatic planning of safety paths for prefabricated components lifting,automatic adjustment of prefabricated components attitudes and seek installation,and construction of gaps between prefabricated components,for lifting and installation of prefabricated components in industrial building construction,the research and development of a special spreader suitable for picking and placing the prefabricated components automatically,and attitude adjustmentautomatically is one of the key technologies for the efficient hoisting of prefabricated components.In this paper,by analyzing the characteristics of precast concrete of prefabricated construction,and the requirements of lifting and installation of the precast concretes,a mechanical structural scheme was designed for the automatic pick and place the precast concretes and adjust the gesture of the precast concretes during the process of hoisting and installing of the precast concretes with the integrated and innovative approach.And have decomposed the designed program according to the function,refined design to the key components,modeled the three-dimensional of the parts and establish a three-dimensional model of the whole structure on this basis,.have analyzed the kinematics,structural stability and simulation verification of the spreader scissor type space manipulator structure,which is the key structure of the overall structure.The main research process and conclusions are as follows:(1)Demand analysis and overall program design: Based on investigation and analysis of the status quo and trends of prefabricated concrete prefabricated buildings at home and abroad,combined with the characteristics of component hoisting operations,summarizing the research and application of prefabricated concrete hoisting technology and equipment,and the existence of And the problems that need to be solved.Determine the functional requirements of automatic pick and place and position adjustment operations for components,and establish the overall design of the spreader by comparing the advantages and disadvantages of different programs according to functional requirements;(2)Step-by-step design: According to the overall design of the lifting slings of the components,it is determined that the electric hooks are used to drive the hooks to realize the automatic hooking off of the hanging points;the scissor-type folding robot arm based on the rope drive is used to realize the lifting.The hook degree of freedom control and the lifting and lowering of the components;the use of the screw screw module mechanism to achieve the adaptive adjustment of the hook spacing of the hanging point of the component;the use of the rotary support mechanism to achieve the horizontal attitude adjustment of the component lifting process.(3)Detailed design of key components: According to the overall design scheme, the automatic decoupling structure,the scissor-type folding lifting structure,the adaptability adjusting mechanism of the hook and the hanging point,the horizontal attitude adjusting slewing mechanism of the prefabricated component and the related key zero The component structure is designed and analyzed,and solidworks is used to model the component in three dimensions and complete the virtual assembly.(4)Motion analysis and structural statics analysis of scissor lifting robot mechanism: analysis kinematics of scissor folding robot arm of the automatic pick and place spreader key components.analysis the maximum deformation of the shear fork-type structure under the influence of wind load by the principle of displacement superposition and matrix displacement principle,and verified by ANSYS workbench.The scissor-type mechanical arm structure was obtained and the deformation displacement of the end was performed.Under the disturbance of the wind load,it was verified that the automatic pick-and-place hook meets the hook condition of the prefabricated component.