In this paper, the design and modeling of a large amplitude compliant revolute joint are introduced. Based on the implementation of multimaterial additive manufacturing (MM-AM), the joint is of interest for robotic contexts where the design of compact and accurate compliant mechanisms is required. The joint design is first experimentally proven to offer a large range of motion and satisfying kinetostatic properties. A parametric study is then conducted using numerical simulation to define the most interesting geometries. An experimental study is in a third step presented to estimate the rotational stiffness, including the manufacturing impact. A stiffness model is provided for relevant geometries, and their use is finally discussed in the context of compliant mechanism design.

Linear actuation is a basic need in robotized manipulation of surgical instruments, that must comply with a challenging environment in terms of safety, compactness and now often compatibility with imaging modalities like CT or MRI. In this paper, we focus on needle manipulation for interventional radiology. We propose a needle driver, i.e. a linear actuator for needle insertion, based on the inchworm principle combined with pneumatic energy. Our first contribution is to propose, model and implement the device using a so-called auxetic structure. Its use increases achievable displacement under pressure and provides sufficient off-axis stiffness to use the actuator without additional guidance. Simplified modeling is introduced for the actuator synthesis. Our second contribution is to implement the actuator with multimaterial additive manufacturing combining rigid and flexible materials to increase compactness. As a third contribution, initial assessment of component sterilization and compatibility with X-ray and MRI imaging modalities is presented.

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In this paper, a new multifunctional compliant joint is introduced for the design of unibody robotic mechanisms. Developed in the demanding context of interventional MRI, the compliant joint integrates kinematic, actuation, braking and sensing functions. Such integration is performed thanks to multimaterial additive manufacturing. Design and experimental behavior of the component are presented. A robotic assistant built with the proposed component and made of a single element is then introduced. It offers interesting performances while being compact and MR-compatible.