Study Of A Remote Robot-assisted Ultrasound Imaging System

In modern medical imaging,ultrasound scanning is widely used in the diagnosis of human organs because of its low cost,no harm and high imaging efficiency.The quality of ultrasound imaging largely depends on the professional skills of doctors.In remote or poor areas,there are few experienced ultrasound technicians,and the application of ultrasound will be very limited.In addition,ultrasound technicians often need to maintain a long-term uncomfortable posture in the process of ultrasound examination,which will also cause repetitive muscle damage to technicians.Therefore,the research of ultrasonic imaging assisted by master-slave teleoperated robot is of great practical significance to solve this problem.In this paper,a corresponding experimental platform is built for the master-slave heterogeneous robot-assisted ultrasound imaging system,and the key technologies such as motion control,force feedback and system random error propagation are studied.The main contents are as follows:Firstly,the master-slave control system is selected according to the requirements of ultrasonic scanning task.The research status of the master-slave control strategy and the analysis method of system stability and transparency are investigated,and the position-force bilateral control strategy is selected,and the master-slave workspaces mapping methods are summarized.Secondly,the master-slave robot assisted ultrasound imaging system is built,and the overall system framework,the master subsystem and the specific components of the slave subsystem are introduced.This paper also describes the functions that need to be realized in the system,as well as the development platform,development language and function library used in the software realization,and determines the choice of communication port and communication mode between the slave and the master computer.Thirdly,the bilateral control strategy in the scanning system of the ultrasonic robot is proposed.As for the motion control,firstly,the linkage mechanism is modeled by D-H method,and the motion equation is derived under the representation of homogeneous transformation.Then,the pose representation methods in robotics are analyzed.Through the modeling of the master and the slave,the forward kinematics equation of the master and the forward,inverse kinematics equation of the slave are derived.Then the workspaces of the master and slave are analyzed separately,and the master-slave speed control method of position and pose separation is proposed to meet the requirements of ultrasonic scanning task.As for the realization of force feedback,the use of HDAPI in the secondary development is described in detail,and the workflow of the development of force rendering program is given.Fourth,the origin and properties of the errors in the robot are introduced.For the random errors of the system,the transformation of the covariance matrix of the errors in a single rotation operation under different reference frames is derived,and then the covariance matrix relationship of the errors under the transmission of the series chain is derived.The propagation expression of covariance matrix of pose error is proposed under the master-slave pose separation velocity control strategy of ultrasonic robot system.Finally,in order to verify the feasibility of the master-slave robot assisted ultrasonic imaging system and the effectiveness of the system strategy,the motion control,force feedback effect and error propagation experiments are analyzed.The experiments show that the master-slave speed tracking of the system is good without considering the inherent noise of the robot,and the force feedback strategy can help doctors to judge the position of the probe and provide doctors with a sense of presence.The simulation experiment verifies the validity of the error propagation algorithm.