Category: Publications

Abstract

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.

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Preliminary development of a skull-mounted lightweight parallel robot toward minimally invasive neurosurgery (PDF Free Download). Available from: [accessed May 30 2018].

Abstract

The introduction of surgical robots improves the quality of healthcare due to the minimal invasiveness, reduced pain of patients, improved efficiency, accuracy, and the efficacy of surgery. The majority of the existing surgical robotic systems are based on master–slave teleoperation mode. The emerging handheld collaborative control modes in robotic systems omit the teleoperation master, and instead use handheld intelligent controls to directly drive its actuator end in order to eliminate motion control uncertainties such as tremors. This chapter puts forward a novel kind of handheld robot system driven by magnetic actuators based on the magnetically suspended technology. The configuration analysis and the design method of magnetic bearing with current bias are presented, and then the analysis and method of the 1-DOF (Degree of Freedom), 3-DOF, and 4-DOF magnetic suspension-based robotic actuator systems are proposed in details.

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Advantages of flexible polymer materials with developments in refined magnetic actuation can be intertwined for a promising platform to work on a resilient, adaptable manipulator aimed at a range of biomedical applications. Moreover, soft magnetic material has an inherent property of high remanence like the permanent magnets which can be further refined to meet ever-increasing demands in untethered and safe-regulated medical environments. In this chapter, we focus mostly on different avenues and facets of flexible polymer materials in adaptable actuation and sensing in the context of magnetic field for range of biomedical applications.

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With the advancement in robotics technology, medical field is evolving more with minimally invasive to noninvasive procedures. Minimally invasive surgical procedures have gained ever-increasing popularity over the past decades due to many of their advantages compared to traditional open operations, such as smaller incisions, faster recoveries, fewer complications, and shorter hospital stays. Robot-assisted minimally invasive surgery promises to improve the precision, dexterity, and stability of delicate procedures. Among these technologies, there is a demanding clinical need to progress the field of medical robotics in connection with noninvasive surgery. For this, the actuation and sensing in the future robotic surgery systems would be desired to be more wireless/untethered. Out of many promising wireless actuation and sensing technologies, one of the most patient friendly techniques to use is electromagnetic or magnetic actuation and sensing for feedback control and manipulation. In this book, we have intended to elucidate the recent related research and developments behind the electromagnetic actuation and sensing implemented in medical robotics and therein.

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This chapter covers the design principles of magnetic actuated catheter robot and is outlined as follows. Section 1 discusses key fundamental principles to design for an electromagnetic catheter/guide wire type surgical robot. The clinical perspectives are covered in Sect. 1.1 and in Sect. 1.2 the overarching electromagnetic theory is mentioned. Electromagnetic systems can be further decomposed into the stators (stationary wound coils) and actuators (moving part usually consists of permanent magnet), where the stators can be interpreted as the input and the actuator the output. Section 2 will cover the design consideration of stators and Sect. 4 the design principles of the actuators. Sections 2 and 3, aim to provide the reader with an intuitive approach to designing their own electromagnetic system. Section 3 will further exemplify principles covered in Sects. 2 and 3 with a fabricated prototype from our lab. These electromagnetic catheter systems can be classified by many parameters; one important parameter is the bending angle and will be addressed in Sect. 4. The use of this angle is demonstrated for a surgical context. This chapter concludes in Sect. 8, providing an overview of the works presented and the future directions.

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This chapter elucidates comprehensive overview of magnetically actuated microbots for various biomedical applications, discover recent developments and show a possible future scope and challenges therein. We confine our biomedical applications and present state of the art mostly related to translational research and near term deliverable possibilities to make in vivo applications. We will first demonstrate a brief overview of the potential medical applications and recent state of the art magnetically actuated microbots. After that, we will briefly touch upon various aspects of magnetically driven magneto-responsive microcapsules for targeted Drug Delivery (TDD) applications. In this part, we will provide a brief literature review in the nexus of magnetic micro robotics with design specifications for drug delivery. Finally, we will illustrate magnetically manipulated self-propelled microjets for biosensing as future perspectives.

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Magnetically Actuated Minimally Invasive… (PDF Download Available). Available from: [accessed May 30 2018].

Abstract

Biomedical robotic applications with accuracy requirements demand real-time position and orientation tracking, such as in the field of human motion tracking, rehabilitation, surgical instrument tracking, among many others. Among the state-of-the-art tracking technology, magnetic sensing method is an effective technology to provide fast and accurate tracking result without suffering from occlusion drawbacks. Magnetic sensing techniques are used to sense the distribution of a magnetic source field. With the sensing signals, the pose (position and orientation) between the sensor(s) and the source(s) can be estimated according to the magnetic field distribution model. In contrast to other optical tracking technologies in the clinical setup, magnetic sensing has no line-of-sight problem and is easy to be embedded with many instruments. Therefore, it is useful in intracorporeal applications to provide the location information of the tracked targets inside the human body. For this reason, magnetic sensing techniques have potential to further improve the applications of computer assisted surgeries. For example, flexible curvilinear manipulators or endoscopic devices nowadays need to be tracked in real time for better and safer operations. This chapter gives an overview of how the magnetic sensing technology works in the field of medical instrument tracking. After that, the sensing applications will be given in detail. Three typical medical applications will be discussed: (1) magnetic sensing for wireless capsule robots; (2) Current magnetic sensing devices in clinic setups; and (3) magnetic sensing for flexible surgical robots.

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In this chapter, motion of magnetic particles were captured using ultrasound imaging with contrast-enhanced microbubbles. Ultrasound videos were captured and analyzed by the created tracking algorithm to determine the efficiency and accuracy of the algorithm. It is necessary to ensure an efficient and accurate tracking method of the particles in order to evaluate future in vitro or in vivo applications of the microbubbles, when implanted into an enclosed system and imaged using ultrasound. First, it was found that the porous structure of the magnetic microbubbles could be successfully fabricated based on a gas foaming technique, using alginate (low viscosity, 2% (w/v)) as the polymer, mixed homogeneously with sodium carbonate (4%) solution. The reaction between sodium bicarbonate and hydrogen peroxide (32 wt %) in the collecting solution allowed the creation of encapsulated microbubbles. The alginate went under crosslinking in the collecting calcium chloride (25% w/v) solution. Second, it was proven that the encapsulated microbubbles enhanced the resultant ultrasound images, with the air bubbles appearing as bright white spots. In contrast, the solid spheres appeared dull and at times could not be seen under ultrasound. The contrast enhancing properties of the microbubbles allowed the microbubbles to be detected by the tracking algorithm, as compared to the solid spheres which could not be detected at all. Third, ground truth of the (x, y) coordinates of the microbubble centroids were determined using manual selection by the user mouse. Based on the accuracy analysis done, the accuracy of the tracking algorithm was 3.33 pixels, or 0.0354 cm, between the algorithm detected and the manually selected (x, y) coordinates of the centroids. Also, the optimal number of particles to be tracked was up to five particles with an accuracy studies.

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In our daily life, we, human beings use our hands in various ways for most of our day-to-day activities. Tracking the position, orientation and articulation of human hands has a variety of applications including gesture recognition, robotics, medicine and health care, design and manufacturing, art and entertainment across multiple domains. Out of the various tracking methods, vision based tracking is an efficient and widely used method. Several devices have been developed by researchers and engineers to track objects using vision. The Leap Motion controller is one such device. However, visual tracking is an equally complex and challenging task due to several factors like higher dimensional data from hand motion, higher speed of operation, self-occlusion, etc. This paper puts forth a novel method for tracking the finger tips of human hand using two distinct sensors and combining their data by sensor fusion technique. The proposed method is tested using standard human hand gestures and the results are discussed. Finally, a soft robotic gripper was operated remotely based on Leap Motion hand tracking and the proposed sensor fusion method.

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This work presents a novel soft actuator with a 3D-printed elastic body based on a fused-deposition-modeling technique and with tendon actuation based on flexible shafts, which allow push, pull, and twist torque transmissions. The combination of the soft body and flexible shaft furnishes an easy-making, modular and functional unit that possesses softness and enables three degrees of freedom. We derive the kinematics and statics of the actuator based on the assumption of piecewise constant curvature, and identify the parameters experimentally. To understand the performance of the soft actuator in different design and fabrication settings, extensive experiments are performed to compare different shapes of cross sections, infill densities, infill patterns, dentation structures and moment arms in terms of generating forces under the same pulling forces. In addition, experimental validations are performed to characterize other properties such as workspace, hysteresis, pushing force, transmitted torque, and tip force under both bending and twisting. Finally, three potential applications, i.e., a soft robotic hand, a multisegment continuum robot, and a miniaturized drilling device, are prototyped and presented experimentally where the flexibility endowed by the shafts is demonstrated and highlighted. The scalability and modularity are also showcased in the three applications.

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