Omnidirectional motion of an untethered tripodal microrobot using radial piezoelectric actuators

, 12.2 g). Three radial piezoelectric actuators synthesize six circumferential driving forces, while a trajectory interpolation algorithm enables omnidirectional locomotion without attitude turning. By switching between high-frequency continuous and intermittent excitation modes, the robot achieves a wide dynamic range, spanning from a 3 cm/s macroscopic speed to a 0.56 μm microscopic step resolution, thereby enabling both rapid maze navigation and precise cross-scale microscopic observation. Integrating actuation, control, communication, five onboard sensors, and power, the robot execute various inspection tasks with the capability of autonomous navigation and multi-robot coordination. These results validate key performance attributes in achieving both high integration and omnidirectional motion to enhance the ability for inspection and exploration missions.