Evaluation of Motion Compensation Dynamics of the Handheld Robot MINARO HD

Abstract

Current surgical robotic systems consist either of a large serial arm, resulting in higher risks due to their high inertia and no inherent limitations of the working space, or they are bone-mounted, adding substantial additional task steps to the surgical workflow.The robot presented in this paper has a handy and lightweight design and can be easily held by the surgeon. No rigid fixation to the bone or a cart is necessary. A high-speed tracking camera together with a fast control system ensure the accurate positioning of the burring tool, while automatically compensating for movements of the surgeon or the patient’s bone.To evaluate the motion compensation capabilities of the developed robot, an experiment was conducted in which movements of the patient were simulated on the robot’s real time control system and the actual robot had to follow those virtual movements. The positioning error, measured with a tracking camera, was recorded for different velocities of the disturbing movement.A linear relation between the positioning error and the speed of the disturbing motion could be discovered, with a slope of 24 ms and an offset of 0.044 mm.The slope can be interpreted as the latency of the robotic system while following a moving target. Therefore, with a measured latency of 24 ms, the developed robotic system should easily be able to compensate for the patient’s breathing as well as the tremor of the operator, whereas the latter can reach frequencies of up to 12 Hz according to literature.