Mobile Robots - Towards New Applications

Industry is using robots for years to achieve high working precision at reasonable costs. When performing monotonous work, attention of human operators weakens over time, resulting in mistakes. This increases production costs and reduces productivity. There is also a constant pressure to reduce costs for industrial processes while keeping or increasing their quality. The idea of integrating robots into the OR was born over a decade ago. Most of these robots are designed for invasive tasks, i.e. they are active tools for medical treatment. Some are telemanipulation systems, filtering tremor and scaling the movements of the user. Others move according to pre-operatively calculated plans positioning instruments of all kinds. Main goal was to achieve a higher precision in comparison to human surgeons, often ignoring the time- and financial aspect. As the economic situation at hospitals becomes more and more strained, economic factors such as costs, time and OR-utilization become more and more important in medical treatment. Now, only few systems can fulfil both requirements: increase precision and reduce the duration of an intervention. We want to introduce another type of robot which assists the surgeon by simplifying the handling of everyday OR equipment. Main goal is to integrate new features such as enhanced positioning modes or guided imaging while keeping the familiar means of operation and improving workflow. The robotic assistance system works in the background until the user wants to use the additional features. On base of a common non-isocentric fluoroscopic C-arm we will explain the way from a manually operated device into an interactive fluoroscope with enhanced positioning and imaging functionality. We first discuss problems of a common C-arm and present possible solutions. We then examine the mechanical structure and derive the direct and inverse kinematics solutions. In the next section, we describe how the device was equipped with motors, encoders and controllers. Finally, we discuss the results of the functionality study and show ways to improve the next generation of robotized C-arms.