  We present a distributed framework for predicting whether a planned
reconfiguration step of a modular robot will mechanically overload the
structure, causing it to break or lose stability under its own weight. The
algorithm is executed by the modular robot itself and based on a distributed
iterative solution of mechanical equilibrium equations derived from a
simplified model of the robot. The model treats inter-modular connections as
beams and assumes no-sliding contact between the modules and the ground. We
also provide a procedure for simplified instability detection. The algorithm is
verified in the Programmable Matter simulator VisibleSim, and in real-life
experiments on the modular robotic system Blinky Blocks.
