CANopen in tracking devices and robotical systems
CAN Newsletter December 2008
Robotics in medical applications is a fast growing research field with increasing numbers of market-ready developments coming out. These developed robotic systems rely on communication technologies to connect their components and to offer external interfaces. There are several open communication standards used in modern hospitals which are designed for advanced medical devices. The question whether any of these standards is suitable for the special requirements of robotic systems gave the initiative for a project at the Surgical Planning Laboratory. One standard that is being evaluated is CAN with its higher-layer protocol CANopen. For this evaluation we developed a software framework, which allows the simple integration of navigation sensors – such as tracking devices or position-sensors – into a CANopen network. This framework was tested in experiments with an electromagnetic tracking-device and in an MRI-compatible robotic system for prostate needle placements.
Requirements of a robotic system
A typical robotic system consists of several devices such as a manipulator, a user interface, a tracker/registration system, and a robot controller. These components share many needs with medical devices when it comes to the type of the communication network. But due to the high degree of automation a robotic system aims for, the most important aspect is a robust communication with low latency. A suitable network has to guarantee the correctness of the transferred data and has to support real-time messages to allow fast emergency handling. Also because of the increasing speed of developments in the field of robotics the reuse of existing components becomes an essential part of the research. This can be supported by the use of open-source software and for hardware parts the use of standard off-the-shelf solutions, which can be connected in a plug-and-play manner.
