Design of a Magnetic Resonance Imaging-Compatible Cable-Driven Manipulator With New Instrumentation and Synthesis Methods

This paper deals with the design of a cable-driven manipulator (CDM) with instrumented structure for magnetic resonance imaging (MRI)-guided interventions. The strong magnetic field and the limited space inside the scanner constitute two severe design constraints. To handle them, a new synthesis approach for CDM is proposed in order to optimize the device compactness. This approach is based on the use of the zonotope properties to optimize the robot geometry, and the interval analysis tools for its validation. Remote actuation with Bowden cables is considered for MRI-compatibility. High friction along the line transmissions can then be expected which leads to a new instrumentation for cable tension evaluation. A prototype is manufactured and assessed. The principle of the instrumentation is validated as well as the user requirements in terms of workspace and ability to resist to external forces applied by the physician.