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Multifunctional Structures for Attitude Control (MSAC) is a new spacecraft attitude control system that utilizes deployable panels as multifunctional intelligent structures to provide both fine pointing and large slew attitude control. Previous studies introduced MSAC design and operation concepts, simulation-based design studies, and Hardware-in-the-Loop (HIL) validation of a simplified prototype. In this article, we expand the scope of design studies to include individual compliant piezo-electric actuators and associated power electronics. This advance is a step toward high-fidelity MSAC system operation, and reveals new design insights for further performance enhancement. Actuators are designed using pseudo rigid body dynamic models (PRBDMs), and are validated for steady-state and step responses against Finite Element Analysis. The drive electronics model consists of a few distinct topologies that will be used to evaluate system performance for given mechanical and control system designs. Subsequently, a high-fidelity multiphysics multibody MSAC system model, based on the validated compliant actuators and drive electronics, is developed to support implementation of MSAC Control Co-design optimization studies. This model will be used to demonstrate the impact of including the power electronics design in the Optimal Control Co-Design domain. The different control trajectories are compared for slew rates and the vibrational jitter introduced to the satellite. The results from this work will be used to realize closed-loop control trajectories that have minimal jitter introduction while providing high slew rates. 

A new attitude control system called Multifunctional Structures for Attitude Control (MSAC) is explored in this paper. This system utilizes deployable structures to provide fine pointing and large slewing capabilities for spacecraft. These deploy- able structures utilize distributed actuation, such as piezoelectric strain actuators, to control flexible structure vibration and motion. A related type of intelligent structure has been introduced recently for precision spacecraft attitude control, called Strain Actuated Solar Arrays (SASA). MSAC extends the capabilities of the SASA concept such that arbitrarily large angle slewing can be achieved at relatively fast rates, thereby providing a means to replace Reaction Wheel Assemblies and Control Moment Gyroscopes. MSAC utilizes actuators bonded to deployable panels, such as solar arrays or other structural appendages, and bends the panels to use inertial coupling for small-amplitude, high-precision attitude control and active damping. In addition to presenting the concept, we introduce the operational principles for MSAC and develop a lumped low-fidelity Hardware-in-the-Loop (HIL) prototype and testbed to explore them. Some preliminary experimental results obtained using this prototype provided valuable insight into the design and performance of this new class of attitude control systems. Based on these results and developed principles, we have developed useful lumped-parameter models to use in further system refinement.