Application of Preview Information to Pointing Control of Truss Structure Using Artificial Thermal Expansion on Orbit

Pointing performance of the truss structure on orbit which is used for large space telescope is discussed. To achieve advanced science missions, large and precise support structures such as truss structures are needed. However, the preciseness of the structure might be lost due to various disturbances on orbit. Therefore, to realize ultra large and precise support structures, active shape control of the structures is needed. To control the shape, we use artificial thermal expansion caused by heaters instead for mechanical actuators. Control systems without mechanism have high reliability, which is very attractive to use on orbit. However, there are some constraints in the usage of heaters. To improve the control performance under such constraints, we apply “Model based Predictive Control (MPC)” as feedforward control method with preview information. In this paper, we mainly show the effectiveness of MPC compared PI control, which is one of the typical feedback control methods. We constructed structural mathematical model and thermal mathematical model in order to show performance of control system. It is confirmed that total error is decreased by MPC compared with the case of PI control through numerical simulations.