356 research outputs found
Development of a multi-channel concentric tube robotic system with active vision for transnasal nasopharyngeal carcinoma procedures
No full textTowards hybrid control of a flexible curvilinear surgical robot under visual/haptic guidance
No full textComprised of multiple telescoptic precurved tubes that can independently rotate and translate, concentric tube robots (<i>CTRs</i>) are favorable in minimally invasive surgeries thanks to their small size and considerable dexterity along with curvilinear accessibility. However, there is a lack of investigation on improvement of the surgeons' perception which in turn can be used to guide the telemanipulation. In this work, we proposed an eye-in-hand configuration for the concentric tube robot by adding an endoscope to the tip of the inner tube, which provides direct and intuitive visual sensing ability for the operator. Based on this visual feedback, we further developed two frameworks for the hybrid control of <i>CTR</i>, namely Teleoperation Before Visual Servoing (<i>TBVS</i>) and Teleoperation During Visual Servoing (<i>TDVS</i>). The structures of these two frameworks were elaborated with key algorithms derived. The effectiveness of the proposed methods were demonstrated through a series of experiments both in free space and in a confined environment (inside a skull model). The results manifested that the visual guidance had the potential of assisting the operator to control the CTR more efficiently
An image based targeting method to guide a tentacle-like curvilinear concentric tube robot
No full textConcentric tube robot (CTR) comprises several precurved concentric tubes which can rotate and translate independently with respect to each other. Each pre-curved tube of a CTR can be controlled to rotate axially and translate along its axis, which enables the tip to bypass obstacles and finally reach the target position. The concentric tube robots enable surgeons to perform delicate procedures by combining the flexibility of elastic catheters with the use of operation tools, such as needles, forceps and grippers. Hence, many clinical applications of concentric tube robots are promising, such as transnasal robotic neurosurgery. Concentric tube robots are suitable for such minimally invasive surgeries because they are able to present various flexible shapes with great dexterity, which strengthens the ability of collision avoidance and enlarges the reachability of operation tools. This paper describes an image based visual servoing method to control the concentric tube robot so that it can reach a desired position. A model-less control algorithm is developed by first estimating and adjusting the Jacobian matrix based on measurement of each incremental movement traced by a single camera, and then generating the next motion using the estimated Jacobian matrix. Therefore, no kinematic model is required to control the CTR during experiments and the experimental results reveal the feasibility and accuracy of the proposed method. To the best of our knowledge, this is the first work that realizes model-less feedback control of concentric tube robots based on visual servoing
Motion planning of continuum tubular robots based on centerlines extracted from statistical atlas
No full textContinuum tubular robots, which are constructed by telescoping pre-curved elastic tubes, are capable of balancing the force application and steerability during minimally invasive surgeries. These devices are able to reach the desired surgical sites in body cavities without colliding with critical blood vessels, nerves and tissues. However, the motion planning of continuum tubular robots is quite challenging because of their complicated kinematics as well as the high dimensional configuration space. In this paper, a sampling-based motion planning method is proposed based on the Rapidly-exploring Random Tree (RRT) algorithm for continuum tubular robots in 3D environments, such as medullary cavities. The proposed motion planner enables a continuum tubular robot to maneuver roughly along the central axis of the statistical humerus atlas in an approximate follow-the-leader manner. The experiment results have demonstrated the effectiveness and superiority of the proposed motion planning algorithm
Model-free image guidance for intelligent tubular robots with pre-clinical feasibility study: Towards minimally invasive trans-orifice surgery
No full textComprised of multiple precurved concentric tubes, continuum tubular robots are capable to reach surgical targets while bypassing critical anatomical obstacles during minimally invasive surgeries, such as transnasal and transoral surgeries. To automatically track the surgical target and compensate undesired disturbance, an eye-in-hand image-based visual servoing algorithm is presented in this paper to control in-house continuum tubular robots. The proposed visual servoing approach does not require any prior knowledge on kinametic models of the robots in order to avoid the errors introduced by imaging-sensor calibration and 3D position reconstruction. Preclinical cadaveric experiments have been demonstrated in the paper to illustrate the feasibility of the model-free automatic visual servoing method
Development of a compact continuum tubular robotic system for nasopharyngeal biopsy
No full textTraditional posterior nasopharyngeal biopsy using a flexible nasal endoscope has the risks of abrasion and injury to the nasal mucosa and thus causing trauma to the patient. Recently, a new class of robots known as continuum tubular robots (CTRs) provide a novel solution to the challenge with miniaturized size, curvilinear maneuverability, and capability of avoiding collision within the nasal environment. This paper presents a compact CTR which is 35 cm in total length, 10 cm in diameter, 2.15 kg in weight, and easy to be integrated with a robotic arm to perform more complicated operations. Structural design, end-effector design, and workspace analysis are described in detail. In addition, teleoperation of the CTR using a haptic input device is developed for position control in 3D space. Moreover, by integrating the robot with three electromagnetic tracking sensors, a navigation system together with a shape reconstruction algorithm is developed. Comprehensive experiments are conducted to test the functionality of the proposed prototype; experiment results show that under teleoperation, the system has an accuracy of 2.20 mm in following a linear path, an accuracy of 2.01 mm in following a circular path, and a latency time of 0.1 s. It is also found that the proposed shape reconstruction algorithm has a mean error of around 1 mm along the length of the tubes. Besides, the feasibility and effectiveness of the proposed robotic system being applied to posterior nasopharyngeal biopsy are demonstrated by a cadaver experiment. The proposed robotic system holds promise to enhance clinical operation in transnasal procedures
Simultaneous hand-eye, tool-flange, and robot-robot calibration for comanipulation by solving the AXB = YCZ problem
No full textMultirobot comanipulation shows great potential in\ud
surpassing the limitations of single-robot manipulation in complicated tasks such as robotic surgeries. However, a dynamic multirobot setup in unstructured environments poses great uncertainties in robot configurations. Therefore, the coordination relationships between the end-effectors and other devices, such as cameras (hand–eye calibration) and tools (tool–flange calibration), as well as the relationships among the base frames (robot–robot calibration) have to be determined timely to enable accurate robotic cooperation validate the proposed methods. The comparison results from both simulations and experiments demonstrated the superior accuracy and efficiency of the proposed simultaneous calibration method
Recommended from our members
Streamlined Development of Fully Human Antibody Fragments for ImmunoPET Imaging Using Phage Display Technology
No full textExploiting antibodies' highly specific binding affinities to various biomarkers, immuno-positron emission tomography (immunoPET) provides a non-invasive way to obtain whole body information on in vivo molecular events that may be crucial for diagnosis and prognosis, which is increasingly important for diagnostics and prognostics. Small, fully human or humanized antibody fragments are preferred for immunoPET imaging probe development due to their favorable pharmacokinetic properties and low risk of immunogenicity. Phage display technology provides a convenient approach to rapidly generate fully human antibody candidates, showing the potential to accelerate and streamline the development process of antibody fragment based immunoPET imaging probes, which is strongly needed as increasing numbers of targeted therapies are being developed every year. Chapter 2 and Chapter 3 describe the use of a traditional fully human scFv phage display library for developing anti-MET antibody fragments for both immunoPET imaging and potential therapeutic application. Multiple fully human anti-MET scFv clones were isolated and reformatted. Three cys-diabody clones showed high affinities (0.7 to 5.1 nM) and inhibitory effect on MET over-expressing cells. The H2 cys-diabody and minibody were able to distinguish a MET over-expressing gefitinib resistant tumor from the parental tumor at as early as 4 hours post injection, indicating the potential of same day imaging for patient stratification. To further exploit the benefit of the phage display technology and streamline the antibody fragment devlopment, as described in Chapter 4 and Chapter 5, two novel fully human scFv phage display libraries with customized linkers and restriction sites were constructed to simplify the antibody fragment reformatting process. The libraries were used for selections against several different targets and successfully generated multiple positive clones. ScFvs from these libraries were rapidly reformatted into diabodies using the restriction sites in the customized linkers. Size exclusion chromatography analysis of these antibody fragments proved the shortened linkers can successfully induce dimerization for the majority of the diabody clones. Together, the studies presented in this dissertation highlight a successful example of the use of phage display technology for developing fully human antibody fragments for immunoPET imaging and how phage display libraries can be improved to further streamline this process
- …
