This disclosure provides systems and methods for in situ gap inspection in a machine, such as a generator, an electric motor, or a turbomachine. A robotic crawler includes an expandable body, multidirectional traction modules, and sensor modules. The expandable body is movable between a collapsed state and an expanded state. The multidirectional traction modules are removably connected to and positioned by the expandable body and configured to engage opposed surfaces within an annular gap of the machine. The sensor modules are removably connected to and supported by the expandable body and include a plurality of sensor types to inspect the annular gap of the machine.