Building Interior Tubes and Nonimaging Reflectors(BITNR)solar thermal concentrators for mid-temperature applications in snow and dust regions,previously titled BIETR now include non-evacuated tube-receivers.A nonpubli...Building Interior Tubes and Nonimaging Reflectors(BITNR)solar thermal concentrators for mid-temperature applications in snow and dust regions,previously titled BIETR now include non-evacuated tube-receivers.A nonpublic walk-in solar collector space has fixed receiver-tubes with matching involute(rounded W)reflectors forming target-rectangles for augmenting large CPC troughs and relaxed tracking E&W‘wing’reflectors with a glass or solid polycarbonate building envelope collector cover.Reported is a BITNR reflector‘wings’tracker invention by George Helmholz and proof-of-concept development by university undergraduate engineering students.Discussed are:building types,structure,and construction and reflector materials for global applications.BITNR architectural feasibility studies with air and water-steam systems include:small wood frame structures,two-car garages,house size demonstration,long-span atriums,large concourses,towers,additions,and verification-test facilities.Schematic studies indicate integrated solar thermal mid-temperature technologies with building-size nonimaging CPC reflectors are main organizing factors for building design and site planning.BITNR/BIETR undergraduate student mechanical and structural engineering semester projects at the University of Wisconsin-Platteville are reported.A BITNR R&D project proposal is outlined which includes:a greenhouse test facility,evaluation of test stands,and development of a computer simulation design aid for architects.展开更多
An asymmetric actuated 3-PPPS parallel mechanism was analyzed in its application to an aircraft wing adjustment process.The posture alignment precision at the wing ends was enhanced with a kinematic calibration method...An asymmetric actuated 3-PPPS parallel mechanism was analyzed in its application to an aircraft wing adjustment process.The posture alignment precision at the wing ends was enhanced with a kinematic calibration method.A constraint equation was built based on a constraint condition that distances among spherical joints of the mechanism were constant,and further eight groups of analytic forward solutions of all poses of the mechanism were solved.An inverse equation of the posture alignment displacements of aircraft wing parts was built based on space vector chains,and a mapping equation of the pose and geometric errors of the posture alignment mechanism containing 39 error sources was derived by differentiating the kinematic equation of the mechanism.After kinematic calibration experiments,the maximum position error of the posture alignment platform dropped from 2.67 mm to 0.82 mm,the maximum angle error decreased from 0.481° to 0.167°,and the posture alignment precision of the aircraft wing end was improved.展开更多
文摘Building Interior Tubes and Nonimaging Reflectors(BITNR)solar thermal concentrators for mid-temperature applications in snow and dust regions,previously titled BIETR now include non-evacuated tube-receivers.A nonpublic walk-in solar collector space has fixed receiver-tubes with matching involute(rounded W)reflectors forming target-rectangles for augmenting large CPC troughs and relaxed tracking E&W‘wing’reflectors with a glass or solid polycarbonate building envelope collector cover.Reported is a BITNR reflector‘wings’tracker invention by George Helmholz and proof-of-concept development by university undergraduate engineering students.Discussed are:building types,structure,and construction and reflector materials for global applications.BITNR architectural feasibility studies with air and water-steam systems include:small wood frame structures,two-car garages,house size demonstration,long-span atriums,large concourses,towers,additions,and verification-test facilities.Schematic studies indicate integrated solar thermal mid-temperature technologies with building-size nonimaging CPC reflectors are main organizing factors for building design and site planning.BITNR/BIETR undergraduate student mechanical and structural engineering semester projects at the University of Wisconsin-Platteville are reported.A BITNR R&D project proposal is outlined which includes:a greenhouse test facility,evaluation of test stands,and development of a computer simulation design aid for architects.
基金supported by the National Natural Science Foundation of China (No.51275234)the Aeronautical Science Foundation of China(No.20131652027)
文摘An asymmetric actuated 3-PPPS parallel mechanism was analyzed in its application to an aircraft wing adjustment process.The posture alignment precision at the wing ends was enhanced with a kinematic calibration method.A constraint equation was built based on a constraint condition that distances among spherical joints of the mechanism were constant,and further eight groups of analytic forward solutions of all poses of the mechanism were solved.An inverse equation of the posture alignment displacements of aircraft wing parts was built based on space vector chains,and a mapping equation of the pose and geometric errors of the posture alignment mechanism containing 39 error sources was derived by differentiating the kinematic equation of the mechanism.After kinematic calibration experiments,the maximum position error of the posture alignment platform dropped from 2.67 mm to 0.82 mm,the maximum angle error decreased from 0.481° to 0.167°,and the posture alignment precision of the aircraft wing end was improved.
