Deployment analysis and control of deployable space antenna

A deployable space antenna has a deployment mechanism which has high precision and reliability. The articulated mechanism is able to alter its configuration without failure from a compact to deployed shape to meet specific operational requirements. Consequently, the analysis of the dynamic characteristic of the deployment mechanism must be done at an initial design stage. In this paper, the kinematic, dynamic analysis and control methods to predict the deployment motions of the hoop truss deployable antenna are presented. First, the general model of deployment kinematic analysis is established. The model can be applied to carrying out the position, velocity and acceleration analysis of any point on the structure. Second, the dynamic model for the hoop truss deployable antenna is established based on the Lagrange method in multibody dynamic systems and using absolute generalized coordinates, which takes into consideration the dissipative force, torques of torsional springs in hinges and the pretension forces in nets. The force-controlled method is presented to control the deployment motion, and the relation between the driving force and the deployment motion is derived. The variation of the driving force is obtained according to the planned deployment motion. The deployment dynamics of the hoop truss deployable antenna is simulated, and the effects of initial velocity, damping and gravity upon deployment are summarized. Deployment dynamic analysis and control of the hoop truss deployable antenna are carried out taking into account the stiffness of torsional spring, damping in joints, gravity and the pretension forces in nets. The results of simulation experiment validated the proposed method.