Robotic ultrasound probe handling auxiliary by active compliance control

This paper describes a support system for ultrasound (US) probe scanning by a robotic probe holding system to support manual handling of an US probe. The system, consisting of an US probe manipulator with parallel link mechanism and a 6-axis force sensor, is able to hold and manipulate an US probe according to force applied to the probe by a technician. To enable the smooth coordinated control, compliance control is used. Moreover, we have proposed velocity-depended viscosity depending on the velocity of the robot. In this study, the appropriate viscosity corresponding to operational velocity was measured experimentally and the feasibility of the coordinated motion control was validated. The results of the viscosity measurement showed a clear inverse correlation between the viscosity and the operational velocity. In the coordinated motion control evaluation, the relation between the applied force and the robot velocity in the viscosity of high, low, and dynamic velocity-depended coefficient was measured. The result showed the dynamic velocity-depended viscosity provides well-coordinated motion in any operational velocities. The results demonstrated the system has a great potential for support of US diagnosis as an auxiliary medical robot.