Design, manufacturing and control of a non-magnetic pneumatic linear stepper actuator with inchworm kinematics

Abstract:
Over the past decades, pneumatic actuation has emerged as an interesting solution for Magnetic Resonance Imaging (MRI)-compatible robotics. In this paper, a pneumatic linear stepper motor that enables to position medical devices is presented. The proposed actuator is based on inchworm kinematics, and it is composed of three main active chambers: two grippers and one extension chamber. The first part of the paper presents the design and manufacturing of the three components based notably on additive manufacturing of elastomers and rigid polymers, and then the control strategy is described. Experimental results show the MR compatibility as well as the effectiveness of the actuator, especially in terms of achievable speeds through the control of the extension chamber. Testing of the actuator also confirms the interest for the application, with possible evolutions to widen its field of application.