Design of deployable mechanism and accuracy measurement for heavy-caliber film camera

Experimental research on system design of deployable mechanism and accuracy modeling for camera was conducted so as to realize application of heavy-caliber and high-precision spatial film imaging system with high stability to space exploration and earth observation. A systematic design scheme aiming at deployable mechanism of heavy-caliber and high-precision spatial film optics imaging was proposed based on spatial one-dimensional extended arm mechanism. Optical-mechanical structure of deployable film camera was constituted by extended arm of three articulated triangular trusses and primary mirror system of film supported by extended arm. Hinge joint of articulated triangular truss was driven by constant force spring so as to maintain rigidity through locking stop pin and strengthening tensioner after deployment. In consideration of dimension error of unit member for extended arm, hinge gap, and other factors, unit of extended arm was equivalent and precision analysis model was constructed, which was compared with test result of model machine. Deployable mechanism of heavy-caliber deployable film camera was completely designed with folding and deployable rate of 1∶15. Unit of extended arm was subject to repetitive deployable accuracy measurement on the ground. Repetitive deployable accuracy in axis, vertical, and horizontal direction was respectively 24 μm, 261 μm, and 218 μm. It indicates that the extended arm has larger folding and deployable rate. Meanwhile, unit of extended arm has higher repetitive deployable accuracy.