| Solar energy has been one of the most promising clean energy due to its abundant,renewable,non-pollutant and available throughout the year.In order to make full use of solar energy,it is of great significance to develop a lightweight solar tracking and concentrating system(STCS),whether on the ground or in space.For this reason,based on space large deployable cable mesh reflectors,we propose four innovative design schemes of lightweight STCS and conduct in depth research one by one in this dissertation.The main works can be described as folllows.1.The precise calculation method of the sun position and the inverse dynamic model of the 3-RPS(Three-Revolute-Prismatic-Spherical)are established.Prior to designing a lightweight STCS,the required theory is analyzed.First,an efficient precise calculation method of the sun position on the ground is proposed;compared with the Era Shuttle Calendar,the accuracy error of the algorithm does not exceed 0.05°.Second,a precise calculation method of the sun position on a spacecraft is proposed;compared with the existing algorithms,the accuracy of the proposed algorithm is further improved.Third,based on the Newton-Euler equation and considering the friction in the translational hinge,an inverse dynamic model of the 3-RPS(Three-Revolute-Prismatic-Spherical)parallel mechanism is established,and the driving force on each branch chain is obtained;the proposed model can satisfy the application requirement of the 3-RPS mechanism in the space field.2.The large ultralight dish STCS on the ground is designed.Due to the complicated structure,bulky body,and high cost of the traditional dish solar system,its application is hindered.For this reason,a novel large ultralight dish STCS on the ground(the proposed ultralight system)is proposed,which consists of a ring-column cable mesh reflector,a lightweight thermoelectric conversion device,and a 3-RPS solar tracker.Here,take(37)5-m system as a typical case.After designing and optimizing the system,the total mass is 20 kg and the surface density does not exceed 1 kg/m~2.Meanwhile,the system has satisfactory mechanical performance under wind loads.In addition,through theoretical analysis,simulation calculations,and ground experiments,it is verified that the 3-RPS solar tracker has the advantages of simple structure,low energy consumption,and high tracking accuracy.Compared with the traditional dish solar system,the mass of the proposed system is reduced by an order of magnitude,the manufacturing difficulty and cost are significantly reduced,and it can be quickly formed;the output power of the proposed system is conservatively estimated to be about 8.24 k W·h,which can meet the daily consumption of a family in remote or suburban areas.3.The novel portable lightweight STCS on the ground is designed.To meet the requirements of portable applications,based on the proposed ultralight system,a novel portable lightweight STCS on the ground is proposed,which consists of a foldable ring-column cable mesh reflector,a heat collector or thermoelectric conversion device,and a RS-2RPS solar tracker.Here,take(37)1.5-m system as a typical case.Through the analysis of folding and unfolding,static,and energy consumption,it has been verified that the proposed system has the advantages of high storage rate,strong environmental adaptability,and low energy consumption.Meanwhile,compared with the 3-RPS solar tracker,the RS-2RPS solar tracker has a simper structure,and its weight,cost and energy consumption are reduced due to the reduction of a driving device;it can adapt to portable applications better.The mass of the proposed system is 3.39 kg and the surface density is 1.92 kg/m~2.The power density of this system is conservatively estimated to be 260.51 W/kg;compared with the existing portable systems,the power density of the system has obvious advantages.4.The dual-rod-supported polar-axis lightweight STCS on the ground is designed.Compared with the earth-level solar tracker,the polar-axis solar tracker has a simpler structure and lower energy consumption.However,most of the existing polar-axis solar trackers adopt a series type,which has the disadvantages of low tracking accuracy and high energy consumption.For this reason,a dual-rod-supported polar-axis lightweight STCS on the ground is proposed,which consists of a ring-frame-column cable mesh reflector,a heat collector or a thermoelectric conversion device,and a dual-rod-supported polar-axis tracker.Here,take(37)1.5-m system as a typical case.Through theoretical analysis and simulation calculations,it is verified that the system is feasible and has satisfactory performance.The dual-rod-supported polar-axis tracker adopts a parallel type,which overcomes the shortcomings of the solar tracker with series type.Meanwhile,the tracker has a simpler and lighter structure than the three-rod-support tracker.5.The space large deployable concentrating and tracking system with power and communication integration is designed.In space applications,the combination of solar cell arrays and communication antennas can significantly reduce the overall mass,physical size,and cost.Currently,related research mainly focuses on integrating the two on a flat-type system,which has the disadvantage of low surface density.For this reason,a novel space large deployable concentrating and tracking system with power and communication integration for spacecraft flying in a sun synchronous orbit is proposed;it consists of a ring-column cable mesh reflector,an energy conversion device,and a 3-RPS pointing mechanism.In order to achieve integrating power and communication,driven by the 3-RPS pointing mechanism,the proposed system tracks the sun in the sunshine region or turns to face the ground communication or other targets in the earth shadow region.Through theoretical analysis,simulation calculations,and preliminary ground experiments,it is verified that the proposed system is feasibility and has satisfactory performance.Compared with the traditional solar wings,the proposed system has lower surface density and higher power density.The research work in this thesis provides a novel idea for the lightweight design of SCTSs in the ground and in space fields,lays a solid foundation for the engineering implementation of the lightweight SCTSs,plays a key role in the promotion and application of the parallel mechanism with three chains in the field of solar tracking,and makes a significant contribution to the development and utilization of solar energy. |
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