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Creators/Authors contains: "Morimoto, Tania K."

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  1. Free, publicly-accessible full text available October 1, 2023
  2. Free, publicly-accessible full text available July 1, 2023
  3. Concentric tube robots (CTRs) show particular promise for minimally invasive surgery due to their inherent compliance and ability to navigate in constrained environments. Due to variations in anatomy among patients and variations in task requirements among procedures, it is necessary to customize the design of these robots on a patient- or population-specific basis. However, the complex kinematics and large design space make the design problem challenging. Here we propose a computational framework that can efficiently optimize a robot design and a motion plan to enable safe navigation through the patient’s anatomy. The current framework is the first fully gradient-based method for CTR design optimization and motion planning, enabling an efficient and scalable solution for simultaneously optimizing continuous variables, even across multiple anatomies. The framework is demonstrated using two clinical examples, laryngoscopy and heart biopsy, where the optimization problems are solved for a single patient and across multiple patients, respectively.
    Free, publicly-accessible full text available January 1, 2023
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  6. Minimally invasive surgery is of high interest for interventional medicine since the smaller incisions can lead to less pain and faster recovery for patients. The current standard-of-care involves a range of affordable, manual, hand-held rigid tools, whose limited dexterity and range of adoptable shapes can prevent access to confined spaces. In contrast, recently developed roboticized tools that can provide increased accessibility and dexterity to navigate and perform complex tasks often come at the cost of larger, heavier, and grounded devices that are teleoperated, posing a new set of challenges. In this article, we propose a new hand-held concentric tube robot with an associated position control method that has the dexterity and precision of large roboticized devices, while maintaining the footprint of a traditional hand-held tool. The device shows human-in-the-loop control performance that meets the requirements of the targeted application, percutaneous abscess drainage. In addition, a small user study illustrates the advantage of combining rigid body motion of the device with more precise motions of the tip, thus showing the potential to bridge the gap between traditional hand-held tools and grounded robotic devices.
  7. We describe a new series pneumatic artificial muscle (sPAM) and its application as an actuator for a soft continuum robot. The robot consists of three sPAMs arranged radially around a tubular pneumatic backbone. Analogous to tendons, the sPAMs exert a tension force on the robot’s pneu- matic backbone, causing bending that is approximately constant curvature. Unlike a traditional tendon driven continuum robot, the robot is entirely soft and contains no hard components, making it safer for human interaction. Models of both the sPAM and soft continuum robot kinematics are presented and experimentally verified. We found a mean position accuracy of 5.5 cm for predicting the end-effector position of a 42 cm long robot with the kinematic model. Finally, closed-loop control is demonstrated using an eye-in-hand visual servo control law which provides a simple interface for operation by a human. The soft continuum robot with closed-loop control was found to have a step-response rise time and settling time of less than two seconds.
  8. Haptic technology has the potential to expand and transform the ways that students can experience a variety of science, technology, engineering, and math (STEM) topics. Designing kinesthetic haptic devices for educational applications is challenging because of the competing objectives of using low-cost components, making the device robust enough to be handled by students, and the desire to render high fidelity haptic virtual environments. In this paper, we present the evolution of a device called "Hapkit": a low cost, one-degree-of-freedom haptic kit that can be assembled by students. From 2013-2015, different versions of Hapkit were used in courses as a tool to teach haptics, physics, and control. These include a Massive Open Online Course (MOOC), two undergraduate courses, a graduate course, and a middle school class. Based on our experience using Hapkit in these educational environments, we evolved the design in terms of its structural materials, drive mechanism, and mechatronic components. Our latest design, Hapkit 3.0, includes several features that allow students to manufacture and assemble a robust and high-fidelity haptic device. First, it uses 3-D printed plastic structural material, which allows the design to be built and customized using readily available tools. Second, the design takes into account the limitationsmore »of 3-D printing, such as warping during printing and poor tolerances. This is achieved at a materials cost of approximately US $50, which makes it feasible for distribution in classroom and online education settings. The open source design is available at http://hapkit.stanford.edu.« less