Flexible Spacecraft Solar Panel Dynamics

PythonDynamics SimulationModal Analysis

Developed a coupled dynamics model of spacecraft solar panels to capture how propulsion driven pose changes excite structural modes and affect control. The purpose is to predict deformation, vibration, and reaction loads during maneuvers to improve controllability of the system.

Motion induced flexible response

Rigid panel model

Pose change appliedNo structural responseIdealized loads

Flexible panel model

Maneuver excites modesTip oscillationTime-varying reaction loads

Pose commandPanel responseMotion & control

01Problem

Rigid body spacecraft models cannot capture the structural response of large flexible appendages during translation and rotational maneuvers.

Propulsion driven acceleration and rotation can excite the bending modes of large solar arrays, leaving residual vibration even after the spacecraft reaches its commanded pose.
That panel motion generates reaction forces and bending moments at the attachment point, which feed directly back into the spacecraft hub and alter its resulting motion.
Modeling the appendage separately from the vehicle therefore misses the two-way interaction between spacecraft motion and structural deformation, creating issues in creating control systems.

02Approach

Built a reduced order flexible body model in Drake and coupled it directly to the dynamics of a free moving spacecraft hub.

Represented the solar array using cantilever mode shapes and computed each mode’s effective mass, stiffness, damping, and base participation terms.
Implemented the modal equations inside a custom Drake physics simulation node, allowing hub movement to act as base excitation and continuously update panel deformation.
At every integration step, the panel model computes clamp shear forces and bending moments and applies them back to the spacecraft as external spatial loads, creating two-way coupling.

03Result

Demonstrated a coupled spacecraft appendage simulation that reproduced the expected modal behavior and captured how flexible panel motion feeds back into the vehicle.

Tuned the flexible panel to a 0.215 Hz fundamental frequency and recovered the expected oscillatory response after translational excitation of the spacecraft hub.
The simulation reproduced the expected frequency content and coupled response between rigid body motion and the flexible solar array modes.
The resulting Drake framework provides a lightweight way to integrate flexible appendages into spacecraft dynamics without repeatedly rebuilding a full FEM.