Evaluation of robot kinematic performance under motion constraints in a teleoperated robotic ultrasound system

In a teleoperated robotic ultrasound system based on serial robots, a doctor uses a master device to control a slave serial robot for performing ultrasound inspections on patients. To effectively detect organs deep beneath the skin, the robot's motion direction and velocity must be precisely controlled, where the translational or rotational motion is constrained to move separately. During the inspection, the target position and motion velocity need to be continuously synchronized between the master device and the serial robot to ensure optimal coordination. However, the kinematic performance of serial robots is inconsistent across the spatial workspace, leading to issues such as protective stops, velocity fluctuations, and tracking delay errors. This paper proposes an evaluation method for the kinematic performance of serial robots based on the maximum attainable velocity in any direction. An algorithm is described to determine the corresponding maximum achievable translational or rotational velocities when rotational or translational motion is constrained. Experimental results confirm the high accuracy of this algorithm. Consequently, further workspace analysis is conducted to inform the layout and velocity settings of the teleoperated robotic ultrasound system for practical applications.