Month: December 2015

Abstract

Light pipe is a tool providing illumination for delicate operations inside the eyeball in an eye surgery. Traditional light pipes with straight shafts have to be reoriented in order to enlarge its illustration range, which implies more risk of damage to the sclera and requires greater operation space for the handle. In order to overcome these limitations, this paper has proposed a novel robotized handheld light pipe based on concentric tubular structure. Tube parameters are selected based on the anatomical dimension of eyeballs. Novel actuation designs are described to meet the requirements of the intraocular procedures. Intuitive control scheme is implemented to facilitate surgeons’ operations. Furthermore, the benefit of the precurved tube compared with that of a straight tube is evaluated through experiments. It has been demonstrated that the proposed design as a light pipe holds the promise of enhancing intraocular surgeries.

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Abstract

In this paper, we present a novel flexible endoscope (FE) which is well suited to minimally invasive cardiac surgery (MICS). It is named the cardioscope. The cardioscope is composed of a handle, a rigid shaft, a steerable flexible section, and the imaging system. The fexible section is composed of an elastic tube, a number of spacing disks, a constraint tube, and four wires. It employs the constrained wire-driven fexible mechanism (CWFM) with a continuum backbone, which enables the control of both the angulation and the length of the flexible section. Compared to other endoscopes, e.g., rigid endoscope (RE) and fixed-length FE, the cardioscope is much more dexterous. The cardioscope can bend over 180 deg in all directions, and the bending is decoupled from the distal tip position. Ex vivo tests show that the cardioscope is well suited to MICS. It provides much wider scope of vision than REs and provides good manipulation inside confned environments. In tests, the cardioscope successfully explored the full heart through a single hole, which shows that the design is promising. Despite being designed for MICS, the cardioscope can also be applied to other minimally invasive surgeries (MISs), such as laparoscopy, neurosurgery, transnasal surgery, and transoral surgery.

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Abstract

Wheeled mobile robots (WMRs) are often used for maintenance of round pipes or ducts, which can typically be represented as a cylindrical workspace. Working in round pipes or ducts, kinematic models of WMRs are different from those applying on a plane and thus pose significant challenges in terms of kinematic analysis and motion control. To address these challenges, the kinematic properties of WMRs in a cylindrical workspace are analyzed in this paper. First, we discuss the kinematic properties of a single wheel in a cylindrical workspace. Then, we analyze the geometric constraints of WMRs in round pipes or ducts with analytical geometry. Based on these analyses, kinematic properties of WMRs in cylindrical workspaces are discussed with screw theory. A control law based on biaxial clinometer information is proposed, and it enables the robot to move horizontally in round pipes or ducts. Finally, the motion of a single wheel purely rolling in a cylindrical workspace is simulated. Experiments using a car-like mobile robot moving in round ducts are carried out to show the feasibility of the proposed algorithm.

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Abstract

In image-based visual servoing (IBVS), the control law is based on the error between the current and desired features on the image plane. The visual servoing system is working well only when all the designed features are correctly extracted. To monitor the quality of feature extraction, in this paper, a condition monitoring scheme is developed. First, the failure scenarios of the visual servoing system caused by incorrect feature extraction are reviewed. Second, we propose a residual generator, which can be used to detect if a failure occurs, based on the Kalman filter. Finally, simulation results are given to verify the effectiveness of the proposed method.

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Abstract

Light pipe is a tool providing illumination for delicate operations inside the eyeball in an eye surgery. Traditional light pipes with straight shafts have to be reoriented in order to enlarge its illustration range, which implies more risk of damage to the sclera and requires greater operation space for the handle. In order to overcome these limitations, this paper has proposed a novel robotized handheld light pipe based on concentric tubular structure. Tube parameters are selected based on the anatomical dimension of eyeballs. Novel actuation designs are described to meet the requirements of the intraocular procedures. An intuitive control scheme is implemented to facilitate surgeons’ operations. Furthermore, the benefit of the precurved tube compared with that of a straight tube is evaluated through experiments. It has been demonstrated that the proposed design as a light pipe holds the promise of enhancing intraocular surgeries.

full text