Novel miniature MRI-compatible fiber-optic force sensor for cardiac catherization procedures

Proceedings of: 2010 IEEE International Conference on Robotics and Automation (ICRA'10), May 3-8, 2010, Anchorage (Alaska, USA)This paper presents the prototype design and development of a miniature MR-compatible fiber optic force sensor suitable for the detection of force during MR-guided cardiac catheterization. The working principle is based on light intensity modulation where a fiber optic cable interrogates a reflective surface at a predefined distance inside a catheter shaft. When a force is applied to the tip of the catheter, a force sensitive structure varies the distance and the orientation of the reflective surface with reference to the optical fiber. The visual feedback from the MRI scanner can be used to determine whether or not the catheter tip is normal or tangential to the tissue surface. In both cases the light is modulated accordingly and the axial or lateral force can be estimated. The sensor exhibits adequate linear response, having a good working range, very good resolution and good sensitivity in both axial and lateral force directions. In addition, the use of low-cost and MR-compatible materials for its development makes the sensor safe for use inside MRI environments.European Community's Seventh Framework Progra

Image-based Optical Miniaturized Three-Axis Force Sensor for Cardiac Catheterization

In order to determine the cause of and to treat an abnormal heart rhythm, electrophysiological studies and ablation procedures of the heart, sensorized catheters are required. During catheterization, force sensors at the tip of the catheter are essential to provide quantitative information on the interacting force between the catheter tip and the heart tissue. In this study, we are proposing a small sized, robust, and low-cost three-axis force sensor for the catheter tip. The miniaturized force sensor uses fiber-optic technology (small sized multi-cores optical fiber and a CCD camera) based on image processing to read out the forces by measuring light intensity which are modulated as a function of the applied force. In addition, image processing techniques and a Kalman filter are used to reduce the noise of the light intensity signals. In this paper, we explain the design and fabrication of our three-axis force sensor and our approach for reducing noise levels by applying a Kalman filter model, and finally discuss the calibration procedure. Moreover, we provide an assessment of the performance of the proposed sensor

Modular integration of a 3 DoF F/T sensor for robotic manipulators

Robot assisted surgery and minimally invasive robotic surgery inherently entail that the hands of the surgeon indirectly interact with the patient tissues and organs even if the operator is out of the affected body. Hence, transferring sensor information from the inside of the patient to the outside of the surgeon may certainly improve the perception of the robotic enduser. To this aim – within the EU framework of the STIFF-FLOP project (STIFFness controllable Flexible and Learnable Manipulator for Surgical Operations), we developed a novel design of miniaturized and magnetic resonance compatible sensors for force and torque real-time measurements in robotic surgery. The sensor design has a hollow shape, whose geometry allows its integration and embedding within snake-like surgical robots and modular devices. According to typical requirements and specifications of a surgical procedure, the sensor operates in a range of force and torque of 0-5 N and 0-5 N⋅cm, respectively. Due to a customized tool and calibration procedure, an error of less than 15% of sensor range can be obtained. This novel transducer may advance force and haptic feedback in robot assisted and minimally invasive surgeries

DESIGN & DEVELOPMENT OF A 2-DOF MINIATURE FORCE SENSOR FOR SURGICAL PROCEDURES

ABSTRACT Force sensing is an important component for a number of surgical procedures as it can help to prevent undesirable damage to the tissue and at the same time provides the surgeons with a better "feel" of the tool-tissue interaction. However, most of the current commercially available multi-DOF force sensors are relatively large in size and it is a challenge to incorporate them into the surgical tool. Hence, a multi-DOF miniature force sensor is desired and this paper presents the design and development of a miniature 2-DOF force sensor. In order to achieve a miniature force sensor, microfabrication technique is used and the proposed force sensor is a capacitive-based sensor. The proposed force sensor can be used in a number of percutaneous procedures as well as catheter-based procedures. This paper presents the design and microfabrication process of the proposed miniature force sensor

Three-Axis Fiber-Optic Body Force Sensor for Flexible Manipulators

This paper proposes a force/torque sensor structure that can be easily integrated into a flexible manipulator structure. The sensor's ring-like structure with its hollow inner section provides ample space for auxiliary components, such as cables and tubes, to be passed through and, hence, is very suitable for integration with tendon-driven and fluid-actuated manipulators. The sensor structure can also accommodate the wiring for a distributed sensor system as well as for diagnostic instruments that may be incorporated in the manipulator. Employing a sensing approach based on optical fibers as done here allows for the creation of sensors that are free of electrical currents at the point of sensing and immune to magnetic fields. These sensors are inherently safe when used in the close vicinity of humans and their measuring performance is not impaired when they are operated in or nearby machines, such as magnetic resonance imaging scanners. This type of sensor concept is particularly suitable for inclusion in instruments and robotic tools for minimally invasive surgery. This paper summarizes the design, integration challenges, and calibration of the proposed optical three-axis force sensor. The experimental results confirm the effectiveness of our optical sensing approach and show that after calibrating its stiffness matrix, force and momentum components can be determined accurately

Three-Axis Fiber-Optic Body Force Sensor for Flexible Manipulators

This paper proposes a force/torque sensor structure that can be easily integrated with a flexible manipulator structure. The sensor’s ring-like structure with its hollow inner section provides ample space for auxiliary components, such as cables and tubes, to be passed through and, hence, is very suitable for integration with tendon-driven and fluid-actuated manipulators. The sensor structure can also accommodate the wiring for a distributed sensor system as well as for diagnostic instruments that may be incorporated in the manipulator. Employing a sensing approach based on optical fibers as done here allows for the creation of sensors that are free of electrical currents at the point of sensing and immune to magnetic fields. These sensors are inherently safe when used in the close vicinity of humans and their measuring performance is not impaired when they are operated in or nearby machines such as magnetic resonance imaging (MRI) scanners. This type of sensor concept is particularly suitable for inclusion in instruments and robotic tools for minimally invasive surgery (MIS). The paper summarizes the design, integration challenges and calibration of the proposed optical three-axis force sensor. The experimental results confirm the effectiveness of our optical sensing approach and show that after calibrating its stiffness matrix, force and momentum components can be determined accurately

Contact force sensor based on microfiber Bragg grating

We demonstrate a miniature contact force sensor based on a 30-µm diameter microfiber Bragg grating packaged with a conforming elastomer material features extremely high sensitivity up to 0.8-mN to contract force.Department of Electrical EngineeringDepartment of Electronic and Information Engineerin

Contact force sensor based on microfiber Bragg grating

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Review of fiber-optic pressure sensors for biomedical and biomechanical applications

As optical fibers revolutionize the way data is carried in telecommunications, the same is happening in the world of sensing. Fiber-optic sensors (FOS) rely on the principle of changing the properties of light that propagate in the fiber due to the effect of a specific physical or chemical parameter. We demonstrate the potentialities of this sensing concept to assess pressure in biomedical and biomechanical applications. FOSs are introduced after an overview of conventional sensors that are being used in the field. Pointing out their limitations, particularly as minimally invasive sensors, is also the starting point to argue FOSs are an alternative or a substitution technology. Even so, this technology will be more or less effective depending on the efforts to present more affordable turnkey solutions and peer-reviewed papers reporting in vivo experiments and clinical trials.info:eu-repo/semantics/publishedVersio