Ultrasonic robotic surgical navigation

Surgical robot systems, anatomical structure tracker apparatuses, and US transducer apparatuses are disclosed. A surgical robot system includes a robot, a US transducer, and at least one processor. The robot includes a robot base, a robot arm coupled to the robot base, and an end-effector coupled to the robot arm. The end-effector is configured to guide movement of a surgical instrument. The US transducer is coupled to the end-effector and operative to output US imaging data of anatomical structure proximately located to the end-effector. The least one processor is operative to obtain an image volume for the patient and to track pose of the end-effector relative to anatomical structure captured in the image volume based on the US imaging data.