Monitoring the shape and deformation of morphing wings is vital for ensuring multi-mission flight and safety operation.During the morphing process,the complex deformation of the flexible skin wing usually involves lar...Monitoring the shape and deformation of morphing wings is vital for ensuring multi-mission flight and safety operation.During the morphing process,the complex deformation of the flexible skin wing usually involves large amounts of movement,shearing,bending,and distortion.This paper proposes an improved stereo-digital image correlation measurement system designed to characterize full-field complex large deformation of flexible skin shear variable-sweep wings(SVSWs).By minimizing reference image updating frequency using the proposed conditional incremental strategy,effectively addressing the computational failures caused by image decorrelation due to complex large deformations.To improve tracking efficiency and accuracy of uncoded targets in complex backgrounds,an automatic subpixel detection method for circular diagonal targets is presented.A series of experiments are performed on a 1200 mm span flexible skin SVSW to verify the proposed methods.The results show that the length and angle measurement accuracies are better than 0.11 mm and 0.05°,respectively.Based on the measured morphing geometry parameters,displacement and strain fields,the structural integrity and morphing performance of the wing under different loads are discussed.During the shear variable-sweep process,the wingtip load dominates the deflection distribution,while its effect on the strain distribution is relatively minor.The proposed method and system can provide reliable data support for the structural optimization design and safety evaluation of such morphing wings.展开更多
There is an urgent need for new chemical application techniques and sprayers in Chinese orchard spraying.A new tractor-mounted automatic target detecting electrostatics,and air-assisted orchard sprayer was designed an...There is an urgent need for new chemical application techniques and sprayers in Chinese orchard spraying.A new tractor-mounted automatic target detecting electrostatics,and air-assisted orchard sprayer was designed and developed to meet the demand of chemical pest control in orchards.This sprayer light weighted,highly efficient,reduces pesticide use and is friendly to the environment.The techniques of automatic target detecting,electrostatics,and air-assisted spraying were combined in this system.The electrostatically charged droplets are projected toward the target by the assistance of an air stream that increases the droplets penetration within canopy.Experimental results show that the new automatic target detecting orchard sprayer with an infrared sensor can save more than 50%to 75%of pesticides,improve the utilization rate(over 55%),control efficiency,and significantly reduce environmental pollution caused by the pesticide application.At the same time the key technological problems related to air-assisted low volume and electrostatic spraying were solved.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12202282 and 12102267).
文摘Monitoring the shape and deformation of morphing wings is vital for ensuring multi-mission flight and safety operation.During the morphing process,the complex deformation of the flexible skin wing usually involves large amounts of movement,shearing,bending,and distortion.This paper proposes an improved stereo-digital image correlation measurement system designed to characterize full-field complex large deformation of flexible skin shear variable-sweep wings(SVSWs).By minimizing reference image updating frequency using the proposed conditional incremental strategy,effectively addressing the computational failures caused by image decorrelation due to complex large deformations.To improve tracking efficiency and accuracy of uncoded targets in complex backgrounds,an automatic subpixel detection method for circular diagonal targets is presented.A series of experiments are performed on a 1200 mm span flexible skin SVSW to verify the proposed methods.The results show that the length and angle measurement accuracies are better than 0.11 mm and 0.05°,respectively.Based on the measured morphing geometry parameters,displacement and strain fields,the structural integrity and morphing performance of the wing under different loads are discussed.During the shear variable-sweep process,the wingtip load dominates the deflection distribution,while its effect on the strain distribution is relatively minor.The proposed method and system can provide reliable data support for the structural optimization design and safety evaluation of such morphing wings.
文摘There is an urgent need for new chemical application techniques and sprayers in Chinese orchard spraying.A new tractor-mounted automatic target detecting electrostatics,and air-assisted orchard sprayer was designed and developed to meet the demand of chemical pest control in orchards.This sprayer light weighted,highly efficient,reduces pesticide use and is friendly to the environment.The techniques of automatic target detecting,electrostatics,and air-assisted spraying were combined in this system.The electrostatically charged droplets are projected toward the target by the assistance of an air stream that increases the droplets penetration within canopy.Experimental results show that the new automatic target detecting orchard sprayer with an infrared sensor can save more than 50%to 75%of pesticides,improve the utilization rate(over 55%),control efficiency,and significantly reduce environmental pollution caused by the pesticide application.At the same time the key technological problems related to air-assisted low volume and electrostatic spraying were solved.
