Autonomous downhole robot tool string

An autonomous downhole robot (ADR) tool string having an extended longitudinal axis that is configured for navigating and collecting information in a downhole environment, the ADR tool string comprising:

• a sensor head having a cylindrical housing positioned at a distal end of the tool string including:
• a wobbler ultrasonic transducer comprising a tubular structure housing an ultrasonic transducer, the tubular structure being coupled to a distal end of the sensor head via a shaft orientated orthogonally to the longitudinal axis of the tool string wherein the tubular structure is tiltable about the shaft, and wherein the distal end of the sensor head is mounted for panned movement about the longitudinal axis providing two degrees of freedom for the wobbler ultrasonic transducer;
• and
• first and second caliper ultrasonic transducers positioned on the cylindrical housing facing the downhole environment, each being configured to pan about an axis orthogonal to the longitudinal axis of the tool string;
• and
• an electronics bay section coupled to the sensor head including electronic circuits for controlling components of the sensor head.