A cost-effective stereo camera system for online pose control of patient handling robots

Patient handling robots are employed more and more frequently to enable a flexible positioning of the patient for diagnostic and therapeutic purposes. Due to the greatly differing robot loads because of varying patient weights especially serial kinematics are no longer able to keep up with the constantly increasing medical demands for positioning accuracy. In this paper a camera-based measuring system is introduced which can measure the pose of a patient couch mounted on a patient handling robot with high accuracy. Through the use of cost-effective hardware components the stereoscopic system is suitable for a permanent integration into the workspace of the robot. This enables online pose control of the patient couch. In tests on a robot system a maximum positioning error of 0.25 mm was achieved for a diversity of medically relevant poses.