  Soft compliant microrobots have the potential to deliver significant societal
impact when deployed in applications such as search and rescue. In this
research we present mCLARI, a body compliant quadrupedal microrobot of 20mm
neutral body length and 0.97g, improving on its larger predecessor, CLARI. This
robot has four independently actuated leg modules with 2 degrees of freedom,
each driven by piezoelectric actuators. The legs are interconnected in a closed
kinematic chain via passive body joints, enabling passive body compliance for
shape adaptation to external constraints. Despite scaling its larger
predecessor down to 60 percent in length and 38 percent in mass, mCLARI
maintains 80 percent of the actuation power to achieve high agility.
Additionally, we demonstrate the new capability of passively shape-morphing
mCLARI - omnidirectional laterally confined locomotion - and experimentally
quantify its running performance achieving a new unconstrained top speed of 3
bodylengths/s (60 mms-1). Leveraging passive body compliance, mCLARI can
navigate through narrow spaces with a body compression ratio of up to 1.5x the
neutral body shape.
