Our team’s showcasing at innovfest unbound 2018 (attended by ~14,000 key players in the technology and innovation scene, Southeast Asia’s largest innovation festival) for two technologies in flexible robotics: ONR grasper and ACTORS.
cof
Dr. Ren received the 2018 IAMBE EARLY CAREER AWARD from The International Academy for Medical and Biological Engineering (IAMBE) in June of 2018 at The IUPESM 2018 – World Congress on Medical Physics & Biomedical Engineering, Prague, Czech Republic. There are 3 awardees internationally and Dr. Ren is the awardee for Asia-Pacific region according to the IAMBE website. http://www.iupesm2018.org/iambe-award-2018.page. Meanwhile, Dr. Ren gave an invited talk in the EARLY CAREER AWARD session of the conference.
Our team, Yun Hol, Kirthika Senthil, Qinghui Wu (NUH advisor) and Ren, Hongliang (NUS advisor) won the Silver Award for BES Research Presentation at Biomedical Engineering Society 12th Scientific Meeting, for the project in a robotic device for medical applications.
A cerebral or intracranial aneurysm (ICA) is a condition that is defined as a local dilation of an artery in the brain due to locally weakened blood vessel walls. This creates a balloon-shaped bulge in the thin artery wall that can rupture, and the ensuing subarachnoid hemorrhage can cause a stroke, coma, or even death. Therefore, it is of interest to understand how ICAs grow and eventually rupture in order to develop earlier diagnosis or treatment techniques. Current imaging technologies include computed tomography and magnetic resonance imaging, which can be used to generate three-dimensional computer-assisted design models. However, these 3D models only provide the shape of the ICA and monitory macroscopic growth of aneurysms, but are too low resolution to determine the specific wall thickness of vasculature. Aneurysms tend to rupture at the thinnest point in the vessel wall, but it is difficult to predict rupture location from just 3D geometry alone using a CT scan reconstruction.
Dr. Ren was invited to talk at The 13th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems on magnetic medical robotics for neurosurgery (22-26, April 2018 at Singapore).
Image guidance during minimally invasive intravascular interventions is primarily achieved based on X-ray fluoroscopy, which has several limitations including limited 3-D imaging capability, significant doses of radiation to operators, and lack of contact force measurement between the cardiovascular tissue and interventional tools. Ultrasound imaging can be adopted to complement or possibly replace 2-D fluoroscopy for intravascular interventions due to its portability, safety to use, and the ability of providing depth information. However, it is challenging to precisely visualize catheters and guidewires in the ultrasound images. In this paper, we propose a novel method to figure out both the position and orientation of the catheter tip in 2-D ultrasound images in real time by detecting and tracking a passive marker attached to the catheter tip. Moreover, the contact force can be estimated simultaneously as well via measuring the length variation of the marker. A geometrical model-based method is introduced to detect the initial position of the marker, and a Kanade-Lucas-Tomasi-based algorithm is developed to track the position, orientation, and length of the marker. The ex vivo experiment results validate the effectiveness of the proposed approach in automatically locating the catheter tip in ultrasound images and its capability of sensing the contact force. Therefore, it can be concluded that the presented method can be utilized to better facilitate operators during intravascular interventions.
Advantages of soft, flexible materials with developments in refined magnetic actuation can be intertwined for a promising platform to work on a resilient, adaptable manipulator aimed to meet ever-increasing demands in safe regulated medical environments. Taking advantages of these soft magnetic polymers, we propose a novel, soft-squishy and flexible bend sensor by determining the relationship between inductance changes with bending angle. This bend sensor employs flexible wire embedded in a silicone elastomer with the different permeable core. The principle notion is to have a comprehensive analysis of the change in morphology of the sensor with bending angle which can be translated to inductance generated therein. The performance of the sensor is evaluated with various experimental trials while analytical modelling elucidates that the bend angle is linearly proportional to the sensor signal citing R-square value up to 0.9204. The proposed sensor produces the desired output in the EM frequency range of 8 MHz – 10 MHz with a tunable sensitivity of 0.418 mV/rad. The sensor is robust enough to stretch up to twice of its original length. The main advantage of this bend sensor is its simple fabrication technique, flexibility, robustness and economical. Conclusively, this work on induction based tactile bending sensor is proved to produce robust output and can be extrapolated to sense bending angle using induction principle for the rehabilitative device, wearable robots and related biomedical applications requiring low cost, soft and flexible operations.
Flame‐retardant coatings are widely used in a variety of personnel or product protection, and many applications would benefit from film stretchability if suitable materials are available. It is challenging to develop flame‐retardant coatings that are stretchable, eco‐friendly, and capable of being integrated on mechanically dynamic devices. Here, a concept is reported that uses pretextured montmorillonite (MMT) hybrid nanocoatings that can undergo programed unfolding to mimic the stretchability of elastomeric materials. These textured MMT coatings can be transferred onto an elastomeric substrate to achieve an MMT/elastomer bilayer device with high stretchability (225% areal strain) and effective flame retardancy. The bilayer composite is utilized as flame‐retardant skin for a soft robotic gripper, and it is demonstrated that the actuated response can manipulate and rescue irregularly shaped objects from a fire scene. Furthermore, by depositing the conformal MMT nanocoatings on nitrile gloves, the firefree gloves can endure direct flame contact without ignition. Montmorillonite–elastomer bilayer architectures with high stretchability and effective flame retardancy can be applied as flame‐retardant protective skins for soft robotic grippers and nitrile gloves. With the stretchable and flame‐retardant barriers, the soft pneumatic actuator is capable of continuous inflation/deflation within flames and can act as a compliant gripper for manipulating and rescuing irregular objects from a fire scene.
Optical Flow (OF) measures the displacement of the projections of visual landmarks on the image plane and is widely used for motion and structure estimations. Fast rotational motion results in large image motion and poses a major challenge to many OF algorithms. To improve the performance of OF estimations, gyroscopes can be adopted to predict the image motion between adjacent frames when the camera motion is dominated by rotation. This paper first proposes an offline method for calibrating the camera focal length, gyroscope bias, the relative orientation and time offset between the camera and gyroscopes without using a man-made target. Then a simple and efficient method is proposed to aid the OF computation with the gyroscope readings. Our approach is evaluated using a low-cost endoscope-gyroscope system and shows improved visual tracking performance as compared to the standalone OF algorithm. The method is suited for use on lightweight platforms equipped with gyroscopes and an endoscopic camera, which potentially can provide efficient image guidance in endoscopic procedures.
Full-text and more information
Preliminary development of a skull-mounted lightweight parallel robot toward minimally invasive neurosurgery (PDF Free Download). Available from: [accessed May 30 2018].
