Structural Design And Experimental Verification Of Intelligent Variant Based On Air Pressure Drive

Adjusting the structure shape according to the driving environment to improve the driving performance is the future direction of intelligent structure development.Advanced actuator and control technology must be studied to realize complex deformation control of structures.Pneumatic drive has become a hot research topic in recent years because of its light weight,good adaptability,fast response and strong load-carrying capacity.How to improve the accuracy and stability of structural deformation control at low cost has become an important research topic.The purpose of this paper is to study the theory and method of optimum design of single-cell actuator and multi-cell actuator for shape control of variant structure,put forward the optimum design scheme of single-cell structure configuration and driving cell layout of new pneumatic actuator,study the influence of geometric parameters of actuator on the driving performance of deformed structure,and establish single-cell and multi-cell actuator with the aim of optimizing the required deformation.The optimal design model of the actuator and the experimental samples of the multi-cell drive structure made of rubber and Kevlar fibers are developed.The experimental results fully verify the validity and feasibility of the optimal design model of the actuator for structural shape control proposed in this paper.The specific research work of this paper is as follows:(1)The optimum design model and analysis model of pneumatic actuator structure are established.Two kinds of pneumatic driving cells with bending function and elongation function are designed.Using pneumatic driving cells as actuators,the geometric parameters and cell layout are optimized,and a variable multicellular structure with bending,elongation and expansion functions is obtained.Based on the finite element analysis software,the finite element analysis model of multi-cell structure is established,and its deformation capacity and law are analyzed.The simulation results show that the designed multi-cell structure can meet the multi-mode deformation requirements of the intelligent variant structure,and the required driving pressure is small,the response speed is fast,and the bearing capacity is high.(2)According to the requirement of large deformation application and considering the manufacturability problem,a pneumatic driving cell with large deformation function is designed.Based on the designed driving cell,a single-ribbed plate structure and a multi-ribbed plate structure with large deformation function are designed.A topology optimization model is established,which takes the deformation output of the structure as the optimization objective and the driving pressure and load as constraints.Based on the finite element analysis software,the bending deformation performance of the structure is analyzed,and the feasibility of the large deformation variable structure optimization model is verified.A shape adaptive controller is designed.Based on the detected structural deformation,the driving pressure can be automatically adjusted to make the structure have a stable shape.(3)The experimental verification platform of pneumatic variable structure based on LabVIEW and cRIO was built,and the experimental specimens of single cell structure,multi-cell structure,single stiffener structure and multi-stiffener structure of rubber and Kevlar fibers were made respectively.The experimental results show that the multi-mode variable structure can achieve bending,elongation and expansion deformations under different driving pressures;the multi-mode variable multi-cell structure with large deformation capacity can achieve bending deformations of about 30 degrees under driving pressures,and its bending deformation angle is linearly correlated with driving pressures and loads,respectively.The deformation response time is 20 s.The experimental results are in good agreement with the simulation results.