Co-design of strain-actuated solar arrays for precision pointing and jitter reduction

Many important spacecraft operations require precision pointing such as space astronomy and high-rate communications. Traditionally, reaction wheels have been used for this purpose but they have been considered unreliable for many missions. This work presents the use strain-actuated solar arrays (SASA) for precision pointing and jitter reduction. Piezoelectric actuators can achieve higher precision and bandwidth than reaction wheels, and they can also provide quiet operation for sensitive instruments. The representation of the array dynamics in the studies presented here is based on Euler-Bernoulli beam theory for high-fidelity simulations. This work also presents a methodology for the combined design of distributed structural geometry for the arrays and distributed control system design. The array geometry design allows for a distributed thickness profile, and the control design determines the distributed moment on the array. Fundamental limits on slew magnitude are found using pseudo-rigid body dynamic model (PRBDM) theory. A parametric study based on a representative spacecraft model demonstrates the validity of the proposed approach and illustrates optimal design trends.