Development of an isotropic Stewart platform for telescope secondary mirror

Abstract For large aperture telescopes, active control of the secondary mirror is essential for correction of the aberrations. In this paper, an isotropic Stewart platform is developed for the telescope secondary mirror control system, providing 6-DOF high-precision pointing and positioning. The isotropic configuration is designed and one experimental prototype of the isotropic Stewart platform is constructed. Then, the isotropic characteristic is investigated through the verification experiments based on the statics principle. Furthermore, the dynamics model of the isotropic Stewart platform is established and the model properties are analyzed. Finally, the experimental prototype is developed and the decoupled controller is adopted. The experimental results demonstrate the effectiveness of the decoupled control strategy and further validate the proposed isotropic drive mechanism for the telescope secondary mirror.

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