Design And Analysis Of Light-small Off-axis TMA Space Camera Main Structure

With the development and application of space remote sensing technology,lightweight and miniaturization have become an important trend in the development of space cameras.Light-small off-axis TMA space camera studies in this paper not only has the advantages of size,weight,production cycle,but also make full use of the advantages of large field of view and wide band of off-axis TMA optical system,and has great prospects in the field of low cost earth observation and commercial utilization,and has become an important direction for the development of space cameras.The main structure of the camera includes the primary mirror subassembly,secondary mirror subassembly tertiary mirror subassembly and supporting structure.It is the key to decide the quality of camera imaging and realize the lightweight and miniaturization of the camera.Therefore,it is significant to design and analyze the main structure.The difficulties in structural design are analyzed.Light-small off-axis TMA space camera studies in this paper calibre is 120 mm,and focal length is 600 mm.The camera requires small size and light weight.At the same time,it requires the radiometric calibration and on orbit focusing function.After removing the calibration system and the focusing system,the envelope size is less than 300 × 420 × 440 mm and the weight is less than 12 kg.The design allowance is very limited to the main structure.At the same time,the off-axis TMA optical system reflects the distribution of the mirror off axis,which requires high precision and position precision of the mirror surface.It needs the strong mechanical and thermal stability of the main body structure of the camera,which improves the difficulty of the structure design.In order to meet the structural stability and optical imaging quality requirements of the camera,the main structure of the camera is designed and analyzed,including the primary mirror subassembly,secondary mirror subassembly,the tertiary mirror subassembly and the supporting structure,so that the whole machine can adapt to the corresponding mechanical environment,and the main content should be carried out from the following aspects.1.The mirror subassembly was designed and analyzed.Combining light-small off-axis TMA space camera optical system requirements and project reality,the selection of mirror and mirror support structure materials and structural configuration was completed;Taking the primary mirror subassembly as an example,the structure design and lightweight of the mirror body were completed,and the supporting structure of flexible mirror was designed according to the theory of flexible hinge.Finally,dynamic and static analysis,modal analysis and installation accuracy analysis of the mirror subassembly are performed to meet the design requirements.2.The main support structure was designed and analyzed.By analyzing the material and structural configuration commonly used in the supporting structure and combining the actual situation of the camera,the suitable material and structural configuration are selected to check the design and calculation of the supporting structure,so that the supporting structure has sufficient mechanical stability and thermal adaptability.3.Complete analysis of the space camera.The static stiffness analysis,dynamic stiffness analysis,structural strength analysis and thermoelastic analysis of the whole machine are mainly performed to verify the correctness of the main structure design.For the case that the fundamental frequency of the initial design did not meet the design requirements,the feasibility of the camera middle support scheme was discussed through the establishment of a camera vibration equivalent model,which provided a reference for similar space camera installation design.