Mechanism Design And Analysis Of Space Large Aperture Deployable Membrane Optical Imager

With the rapidly increasing demand of space exploration missions,the space optical imaging system with large aperture,high resolution and excellent stability will play an important role in exploration and observation.In order to solve the numerous technical problems of traditional reflective imaging system,membrane based diffraction optical imaging system prove to be a new technological approach.Based on the theory and architecture of diffraction optical imaging,this paper proposed an effective method of system design and analysis of space deployable membrane optical imaging mechanism aimed at large aperture and high resolution.A new deployable imaging mechanism including articulated triangular truss mast and membrane primary mirror supported by the masts was proposed.The articulated triangular truss was designed,as well as joint hinges driven by the special constant torque spring.On account of the movement simulation analysis of the mast,the rate-limiting mechanism was proposed for controlling system expansion speed.In addition,the low gravity experimental environment is designed according to the ground test conditions.The applicability of Stewart parallel mechanism in the primary optical mirror attitude adjusting module was analyzed thoroughly according to constraint conditions including large aperture,short distance and small range of motion,as well as the 3-RRPS six-freedom degrees parallel mechanism.A parameter evaluation method based on controllability and regulation was proposed,and the structural parameters of Stewart parallel mechanism were analyzed respectively.And the position relationship of 3-RRPS six-freedom degrees parallel mechanism was analyzed in the same way.The attitude adjustment mechanism was designed based on the Stewart parallel mechanism,and the motion characteristics was verified.The equivalent continuum beam model of the articulated triangular truss mast established method was proposed on the basis of energy principle,and the feasibility was verified by the prototype developed,and the analysis model of the whole system was proposed.The relation between static characteristic and structural parameter was deduced,and the simulation analysis was carried out.The finite element analysis model of the mechanism was established.The dynamic difference between a single mast and the plurality of mast parallel system was analyzed,and the harmonic response and random vibration analysis were carried out.An accurate analysis model of the triangular truss mast considering the component original dimension error and the hinge clearance was established,and the total error was calculated according to the engineering parameters.The experimental investigation was developed to study the expanding distance accuracy and the repeated accuracy of the mast prototype.In view of the adjustment accuracy of the primary mirror,the positive solution algorithm of the mechanism was established.And the influence of the drive motor accuracy on the operating position was proposed.The axial accuracy of the system was analyzed and some guiding conclusions were primarily obtained.