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Online learning is an important aspect of higher education today. One-third of college students take at least one course online, and almost 70% of chief academic leaders say that online learning is critical to their long-term strategy [1]. Despite the success and growth of online education, the number of courses that currently offer a hands-on laboratory component is extremely limited, resulting in the lack of an entire category of engineering courses.

We present the design, evolution and analysis of "Hapkit," a low-cost, open-source kinesthetic haptic device for use in educational applications. Hapkit was developed in 2013 based on the design of the Stanford Haptic Paddle, with the goal of decreasing cost and increasing accessibility for educational applications, including online teaching, K-12 school use, and college dynamic systems and control courses. In order to develop Hapkit for these purposes, we tested a variety of transmission, actuation, and structural materials. Hapkit 3.0, the latest version, uses a capstan drive, inexpensive DC motor, and 3-D printed structural materials. A frequency-domain system identification method was used to characterize Hapkit dynamics across the various designs. This method was validated using a first principles parameter measurement and a transient response analysis. This characterization shows that Hapkit 3.0 has lower damping and Coulomb friction than previous designs. We also performed a user study demonstrating that Hapkit 3.0 improves discrimination of virtual stiffness compared to previous designs. The design evolution of Hapkit resulted in a low-cost, high-performance device appropriate for open-source dissemination and educational applications.

Growing robots that achieve locomotion by extending from their tip, are inherently compliant and can safely navigate through constrained environments that prove challenging for traditional robots. However, the same compliance and tip-extension mechanism that enables this ability, also leads directly to challenges in their shape estimation and control. In this letter, we present a low-cost, wireless, permanent magnet-based method for localizing the tip of these robots. A permanent magnet is placed at the robot tip, and an array of magneto-inductive sensors is used to measure the change in magnetic field as the robot moves through its workspace. We develop an approach to localization that combines analytical and machine learning techniques and show that it outperforms existing methods. We also measure the position error over a 500 mm × 500 mm workspace with different magnet sizes to show that this approach can accommodate growing robots of different scales. Lastly, we show that our localization method is suitable for tracking the tip of a growing robot by deploying a 12 mm robot through different, constrained environments. Our method achieves position and orientation errors of 3.0 $\pm$ 1.1 mm and 6.5 $\pm 5.4^\circ$ in the planar case and 4.3 $\pm$ 2.3 mm, 3.9 $\pm 3.0^\circ$ , and 3.8 $\pm 3.5^\circ$ in the 5-DOF setting.

Endovascular surgery (ES) is a minimally invasive procedure used to treat diseases such as stroke, coronary artery disease, and aneurysms. Often, the vascular anatomy exhibits high tortuosity and severe angulation, which requires long procedures and significant expertise, and leads to a risk of vessel dissection. Here we introduce a soft, tip-extending robot—the VINE (Vascular Internal Navigation by Extension) catheter—that extends, or “grows,” from the tip when pressurized with fluid. It acts as an access device, pulling a standard catheter to the target site as it grows. We demonstrate how this movement via tip-extension enables the VINE catheter to easily and safely pass through tight curvatures. We also demonstrate the system’s usability in a patient-specific anatomical model under fluoroscopy, even by novices. Overall the VINE catheter has potential to: (i) increase safety, given its inherent limit to stress that it can apply to vessel walls, and (ii) decrease the time and expertise required to successfully complete complex ES cases. The results serve as a foundation for an entire class of devices capable of gaining access to difficult-to-reach locations via navigation through constrained anatomy and illustrate the potential for the VINE catheter to have a significant impact on a range of procedures.

Soft continuum robots exhibit access and manipulation capabilities in constrained and cluttered environments not achievable by traditional robots. However, navigation of these robots can be difficult due to the kinematics of these devices. Here we describe the design, modeling, and control of a soft continuum robot with a tip extension degree of freedom. This design enables extremely simple navigation of the robot through decoupled steering and forward movement. To navigate to a destination, the robot is steered to point at the destination and the extension degree of freedom is used to reach it. Movement of the tip is always in the direction tangent to the end of the robot's backbone, independent of the shape of the rest of the backbone. Steering occurs by inflating multiple series pneumatic artificial muscles arranged radially around the backbone and extending along the robot's whole length, while extension is implemented using pneumatically driven tip eversion. We present models and experimentally verify the growing robot kinematics. Control of the growing robot is demonstrated using an eye-in-hand visual servo control law that enables growth and steering of the robot to designated locations.

Robot-assisted minimally invasive surgical systems enable procedures with reduced pain, recovery time, and scarring compared to traditional surgery. While these improvements benefit a large number of patients, safe access to diseased sites is not always possible for specialized patient groups, including pediatric patients, due to their anatomical differences. We propose a patient-specific design paradigm that leverages the surgeon's expertise to design and fabricate robots based on preoperative medical images. The components of the patient-specific robot design process are a virtual reality design interface enabling the surgeon to design patient-specific tools, 3-D printing of these tools with a biodegradable polyester, and an actuation and control system for deployment. The designed robot is a concentric tube robot, a type of continuum robot constructed from precurved, elastic, nesting tubes. We demonstrate the overall patient-specific design workflow, from preoperative images to physical implementation, for an example clinical scenario: nonlinear renal access to a pediatric kidney. We also measure the system's behavior as it is deployed through real and artificial tissue. System integration and successful benchtop experiments in ex vivo liver and in a phantom patient model demonstrate the feasibility of using a patient-specific design workflow to plan, fabricate, and deploy personalized, flexible continuum robots.

Percutaneous techniques and robot-assisted surgical systems have enabled minimally invasive procedures that offer reduced scarring, recovery time, and complications compared to traditional open surgeries. Despite these improvements, access to diseased sites using the standard, straight needle-based percutaneous techniques is still limited for certain procedures due to intervening tissues. These limitations can be further exacerbated in specific patient groups, particularly pediatric patients, whose anatomy does not fit the traditional tools and systems. We therefore propose a patient-specific paradigm to design and fabricate dexterous, robotic tools based on the patient's preoperative images. In this paper, we present the main steps of our proposed paradigm - image-based path planning, robot design, and fabrication - along with an example case that focuses on a class of dexterous, snake-like tools called concentric tube robots. We demonstrate planning a safe path using a patient's preoperative ultrasound images. We then determine the concentric tube robot parameters needed to achieve this path, and finally, we use 3-D printing to fabricate the patient-specific robot.

Flexible medical robots can improve surgical procedures by decreasing invasiveness and increasing accessibility within the body. Using preoperative images, these robots can be designed to optimize a procedure for a particular patient. To minimize invasiveness and maximize biocompatibility, the actuation units of flexible medical robots should be placed fully outside the patient's body. In this letter, we present a novel, compact, lightweight, modular actuation, and control system for driving a class of these flexible robots, known as concentric tube robots. A key feature of the design is the use of three-dimensional printed waffle gears to enable compact control of two degrees of freedom within each module. We measure the precision and accuracy of a single actuation module and demonstrate the ability of an integrated set of three actuation modules to control six degrees of freedom. The integrated system drives a three-tube concentric tube robot to reach a final tip position that is on average less than 2 mm from a given target. In addition, we show a handheld manifestation of the device and present its potential applications.

Author(s): Lin, Jui-Te | Advisor(s): Morimoto, Tania | Abstract: Technological advancements in video equipment and biocompatible materials has enabled improvements in complex surgery through small incisions. The mastery of these laparoscopic surgical techniques is now a requirement for surgeons, however, the necessary skills are not intuitive and require hundreds of practice hours. The current state of surgical education includes animate models, inanimate physical models, and computer-based simulations, the latter of which are limited by cost, accessibility, and a lack of engagement. We propose a novel low-cost training interface that mimics the laparoscopic surgical environment using customized instruments whose movement and control are used as inputs for video games. The system is significantly less expensive than commercial systems and allows users freedom to select and play any game, enabling a take-home system with potential for higher levels of engagement, as well as familiarity and expertise with ambidextrous laparoscopic hand motion. A preliminary study compared performance on FLS (Fundamentals of Laparoscopic Surgery) testing before and after training. For a precision cutting task, groups that trained on a standard simulator or on the new system with either a non-inverted or inverted hand-instrument mapping, showed statistically significant improvements, warranting further investigation of training with this new system.

Concentric tube robots have potential for use in a wide variety of surgical procedures due to their small size, dexterity, and ability to move in highly curved paths. Unlike most existing clinical robots, the design of these robots can be developed and manufactured on a patient- and procedure-specific basis. The design of concentric tube robots typically requires significant computation and optimization, and it remains unclear how the surgeon should be involved. We propose to use a virtual reality-based design environment for surgeons to easily and intuitively visualize and design a set of concentric tube robots for a specific patient and procedure. In this paper, we describe a novel patient-specific design process in the context of the virtual reality interface. We also show a resulting concentric tube robot design, created by a pediatric urologist to access a kidney stone in a pediatric patient.

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 limitations 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.

Summary form only given. Courses involving a laboratory component are conspicuously missing from the recent upsurge in online courses, limiting student access to hands-on educational experiences. We present a low-cost, open-hardware haptic device, called Hapkit, designed to provide a hands-on laboratory experience in an introductory online haptics course. Hapkit is a one-degree-of-freedom kinesthetic haptic device that allows users to input motions and feel programmed forces. Based on previous haptic paddle designs, Hapkit consists of a motor, magneto-resistive sensor and rotating magnet, laser-cut acrylic structure, friction drive, force-sensitive resistor, and custom Arduino-based controller board. The CAD files, parts list and costs, assembly instructions, and sample software are posted at http://hapkit.stanford.edu so the public can both recreate Hapkit and modify its design. The corresponding online haptics course, piloted in Autumn 2013, will be available as a self-paced course at http://hapticsonline.stanford.edu. In this demonstration, conference attendees will be able to assemble and program Hapkits.