Design, analysis, prototyping, and evaluation of a robotic system for remote ultrasound diagnosis.

摘要

This thesis presents design, analysis, prototyping, and performance evaluation of a robotic system to assist physicians to perform ultrasound examinations on patients located in remote areas. The research is inspired by the desire that uniform healthcare should be available to all citizens including those living in remote and isolated areas with less access to medical experts. The system, presented in this thesis, consists of a force-reflecting hand-controller located at the physician side, and a robotic wrist located at the patient side. The physician manipulates the hand-controller to control the position of the robotic wrist holding an ultrasound probe on the patient's body. The physician observes captured ultrasound images while feeling the palpation forces between the remote probe and the patient's body.;The hand-controller consists of symmetric parallel mechanisms, universal joints, and miniature cable drives. The novel characteristics of the device are: static balancing with a tension spring to reduce operator's fatigue and to enhance the safety of remote examination, kinematically decoupled degrees of freedom each corresponding to a motion of the ultrasound probe, large and singularity-free workspace (a conical workspace with a vertex angle as much as 50°), base-mounted actuators, and fixed center-of-motion to enhance operator's performance. The weight of the moving elements is 452 gr.;In collaboration with Winnipeg Children Hospital, an ultrasound technologist successfully performed ultrasound imaging of kidney, heart, spleen, and liver using the robotic devices developed in this thesis.;The robotic wrist utilizes a novel combination of asymmetric parallel mechanisms, universal telescoping joints, ball screws, cable drives, and ball splines. The unique characteristics of the device are: kinematically decoupled degrees of freedom, one-to-one position correspondence with the corresponding haptic device to make the usage of the system intuitive and to reduce physician's training time, singularity-free workspace (a conical workspace with a vertex angle as much as 50°), base-mounted actuators to reduce inertia and simplify device sterilization, and remote center-of-motion to facilitate three dimensional ultrasound imaging. The weight of the moving elements is 2.5 kg. The sliding motion of the wrist is able to apply palpating forces up to 24 N. The maximum velocities of the ultrasound probe during examination for pitch, yaw, rotational, and palpating motions are 27 deg/s, 32 deg/s, 68 deg/s, and 3 mm/s, respectively.