Design And Analysis Of Kinematic Supporting Project For Spatial Optical Remote Sensor

The supporting structure of spatial camera was used to support and install a spatial camera. It was a very important mechanical module of the whole camera system, through which satellite’s mechanical inspritment was transferred to spatial remote sensor. Its structure design was the quarantee for imaging quality. The supporting structure must possessed good kinematic precision and dynamic performance. A kinematic supporting project had been designed in order to resolve installation and high precision positioning for spatial optical remote sensor. This paper was developed as following:.1, Constraint-screw theory was introduced, including the concept of screw, modified K-G equation, compute method of constraint and DOF, and physical meaning of communal constraint and redundant constraint. In this paper, the section of kinematic design was based on this theory, so it was necessary to introduce this theory shortly.2, A mode of3-RRR spatial parallel mechanism was proposed as kinematic support scheme. Constraint-screw algorithm was applied to analyze the problem how per embranchment circumscribed working platform’s degree of freedom at ideal state, and all embranchments acted on the working platform together that gave birth to communal constraint and redundant constraint. After that, the clearances of kinematic pairs in unit of micrometer were inducted to investigate the assignment of degree of freedom at actual circumstance, the quantity of over-constraint at idea state was compared with the situation at actual state including clearances.3, Appropriate materials were selected to design the supporting structure because of density, elastic modulus and so on. Some formula of material mechanism were adopted to validate the intensity. Some module’s section was in figure of hollow rectangle, also the length of components was abbreviated to enhance the stability of the structure. Experimental results indicate that the value of remote sensor’s displacement along x,y,z axis is in0.048mm,0.046mm,0.042mm. Its rotation angle around x, y, z axis is3.95",1.86",1.81". This supporting project satisfies the request for support and high precision positioning for spatial optical remote sensor.4,Computer simulation and experiment were both adopted to study the dynamic performance of supporting structure. Hertz elastic contact theory was used to calculate the nonlinear contact boundary conditions, and modified Craig-Bampton method was adopted to simulate supporting components’flexible deformation. Second Lagrange equation with multiplier was used to establish system’s dynamic model. ADAMS software and experiment method were used to research the dynamic characteristics of supporting structure. Through the frequence response to the sinusoidal and random excitation, resonant frequency and the amplitude coefficient were calculated, also system’s natural frequency was computed.Finally, experimental results show that, the supporting structure has good kinematic precision and dynamic performance, and it can fully meet the kinematic and dynamic requirements. The programme meets supporting and positioning requirements for spatial optical remote sensor. The scheme that is proposed in this paper has originality, and also has an important reference value to the similar kinematic supporting structure.