Surgical Applications of Compliant Mechanisms:A Review

Current surgical devices are mostly rigid and are made of stiff materials, even though their predominant use is on soft and wet tissues. With the emergence of compliant mechanisms (CMs), surgical tools can be designed to be flexible and made using soft materials. CMs offer many advantages such as monolithic fabrication, high precision, no wear, no friction, and no need for lubrication. It is therefore beneficial to consolidate the developments in this field and point to challenges ahead. With this objective, in this article, we review the application of CMs to surgical interventions. The scope of the review covers five aspects that are important in the development of surgical devices: (i) conceptual design and synthesis, (ii) analysis, (iii) materials, (iv) maim facturing, and (v) actuation. Furthermore, the surgical applications of CMs are assessed by classification into five major groups, namely, (i) grasping and cutting, (ii) reachability and steerability, (iii) transmission, (iv) sensing, and (v) implants and deployable devices. The scope and prospects of surgical devices using CMs are also discussed

Soft Embedded Sensors with Learning-based Calibration for Soft Robotics

In this thesis, a new class of soft embedded sensors was conceptualized and three novel sensors were designed, fabricated, and tested for small force range soft robotic applications. The proposed soft sensors were consisted of a gelatin-graphite composite with piezoresistive characteristics. Principally, the sensing elements of the proposed class of soft sensors were moldable into any shape and size; thus, were embeddable and scalable. The sensing elements were directly molded into soft flexural structures so as to be embedded in the flexures. For each sensor, first a mechano-electrical phenomenological model for the exhibited piezoresistivity was proposed and validated experimentally. Afterwards, the sensors were subjected to a series of external forces to obtain calibration data. Given the complexity of the piezoresistivity and intrinsic large deformation of the soft bodies and sensing element, learning-based calibration approach were investigated. To compensate for ratedependency and hysteresis effects on sensor readings in calibration, rate-dependent features were selected for learning-based calibrations. Consequently, the first sensor of this research, i.e., one degree-of-freedom (1-DoF) force sensor, exhibited a force range of 0.035-0.82 N force measurement range with a mean-absolute-error (MAE) of 3.7% and a resolution of 4% of full-range. The second sensor, i.e., 3-DoF had a measurement range of up to 0.3 N with an MAE of 0.005 N and a resolution of 0.003 N. The third sensor, 6-DoF force-torque sensor, had a force range of up to 110 mN with an MAE of 7.4±6.5 mN and resolution of 1 mN and a torque range of 6.8 mNm with an MAE of 0.24 mNm. Comparison with the state-of-the-art and functional requirements of intraluminal procedures showed that the the proposed sensors were fairly compatible with the requirement and showed improvement of the state of the art. The major contribution of this research was to propose a scalable sensing principle that could adapt its shape to the shape of the host body, e.g., flexural robots. Moreover, this research showed nonlinear learning-based calibration is a fitting solution to overcome limitations of the state-of-the-art in using soft elastomeric sensors

Soft pneumatic actuators: a review of design, fabrication, modeling, sensing, control and applications

Soft robotics is a rapidly evolving field where robots are fabricated using highly deformable materials and usually follow a bioinspired design. Their high dexterity and safety make them ideal for applications such as gripping, locomotion, and biomedical devices, where the environment is highly dynamic and sensitive to physical interaction. Pneumatic actuation remains the dominant technology in soft robotics due to its low cost and mass, fast response time, and easy implementation. Given the significant number of publications in soft robotics over recent years, newcomers and even established researchers may have difficulty assessing the state of the art. To address this issue, this article summarizes the development of soft pneumatic actuators and robots up until the date of publication. The scope of this article includes the design, modeling, fabrication, actuation, characterization, sensing, control, and applications of soft robotic devices. In addition to a historical overview, there is a special emphasis on recent advances such as novel designs, differential simulators, analytical and numerical modeling methods, topology optimization, data-driven modeling and control methods, hardware control boards, and nonlinear estimation and control techniques. Finally, the capabilities and limitations of soft pneumatic actuators and robots are discussed and directions for future research are identified

Developing a labour and birth orientation program

Purpose and Background: The purpose of this practicum was to re-develop the labour and birth orientation program at the Queen Elizabeth Hospital in Charlottetown, PE. The need for this practicum was identified following a substantial staff turnover. This potentiated a need for orientation of a number of registered nurses to labour and birth. During orientation, presentation of program content consisted of two days of traditional classroom style teaching followed by a six-week preceptorship, where the majority of labour and birth knowledge and content would be acquired during this time and facilitated by the preceptor. This led to inconsistencies in information provided to new learners. Evaluation was determined by a written exam and preceptor feedback; inconsistencies were noted by unit leaders and preceptors with these methods of evaluation. Methods: A literature review was undertaken to explore the theoretical underpinnings for the program, Kolb’s Experiential Learning theory, and to explore the literature on the benefits and orientations programs. Also, a consultation plan and report was conducted, which provided a theoretical and evidence-based framework program development. Conclusion: The final program describes methods by which labour and birth content is presented to orientees, and includes 16 learning modules; 15 of which were developed. Additionally, the formal orientation process, method for evaluation of the orientee, and methods for remediation for individuals who are having difficulties with the orientation process are described throughout the program

Design and Analysis of Soft Actuator with Enhanced Stiffness with Granular Jamming

The field of soft robotics has been increasing popularity and importance in last decade with its groundbreaking applications in the field of delicate food handling industry and rehabilitation of limbs and fingers of stroke affected patients. The area of soft robotics seeks to improve robot safety, allowing them to function in circumstances where standard robots cannot. This research is focused on pneumatically actuated soft robots as they are efficient, easily controlled, affordable, and well researched. These robots consist of one or more soft actuators, made of silicone elastomers with low material hardness. Low hardness silicone actuators are structurally weak and cannot generate functional forces, which can be rectified by simply increasing the hardness of the material, resulting in compromising softness of the robot. This research attempts to provide a solution to increase structural stability and force output of soft actuator without compromising softness of the material. These were achieved in two ways; one, by improving the cross-sectional profile of the actuator, with an addition of vacuum functionality which increases degree of freedom by one. Two, by attaching a granular jamming component to the actuator, which can change its stiffness actively based on the vacuum applied to it. In this research, the soft actuator was made of Eco-Flex 00-30 silicone and ground coffee was used as granular material for jamming. The actuator was designed on CATIA, and simulation analysis was carried out in ANSYS. A simulation study is conducted to optimize the design parameters to improve bending angle. The jamming components are attached on either side of the actuator and filled with ground coffee which provides controlled stiffness. The actuator was fabricated by molding, all molds are 3D printed with polylactic acid. The actuator was powered by an electric air pump. The actuator is evaluated for bending angle and blocking force at the tip. 280% more bending was achieved under vacuum when compared to conventional design. The blocking force was increased by 270% upon implementing jamming component. The force output obtained per unit pressure applied when compared to present literature increased by 4 times. Lastly, these methods can be implemented to improve the performance of any soft pneumatic actuators

Stimuli-Responsive Microtools for Biomedical and Defense Applications

We live in a 3D world which has embraced ever shrinking technologies, yet the techniques used to create these micro- and nanoscale technologies are inherently 2D. Self-assembly of 2D templates into 3D devices enables the creation of complex tools cheaply, efficiently, and in mass quantity. I utilize this technique to create stimuli-responsive microgrippers, which are shaped like hands with flexible joints and rigid phalanges and range in size from 10 µm to 4 mm. Intrinsic stress within the hinges provides all the energy necessary for gripping, and thus they require no wires or batteries for operation. Here, I demonstrate their use for both biomedical and defense applications. These microgrippers can be used as microsurgical tools, gripping onto tissue in response to body temperature and excising tissue from the gastrointestinal tract in both in vivo and ex vivo porcine models. A Monte Carlo model confirmed that these tiny tools has a higher probability of sampling tissue from a lesion as compared to the traditional biopsy foreceps. These grippers were scaled down to 10 µm and used to capture single cells for in vitro isolation, imaging, and assays. All-polymeric, porous, stimuli-responsive therapeutic grippers or “theragrippers” which swell and de-swell around body temperature were created for drug delivery applications. These theragrippers can be loaded with commercial drugs for biphasic, site-specific controlled release and were successfully demonstrated in an in vitro and an in vivo model. For defense applications, integrating microelectronics like RFID’s onto the microgrippers creates tagging, tracking, and locating (TTL) devices capable of latching onto clothing, hair, and moving animal targets. This integrated design is enabled using high throughput solder-based self-assembly. This defense application, particularly reliant on covert, wireless technology, benefits from our novel photothermal actuation mechanism using low power, handheld lasers. In addition to triggering microgripper closing, this actuation scheme also enables complex sequential folding pathways, a step towards programmable matter

Development and marketing of a prosthetic urinary control valve system

An implantable prosthetic for the control of urinary incontinence was developed and marketed. Three phases are presented: bench development studies, animal trials, and human clinical trials. This work was performed under the direction of a Research Team at Rochester General Hospital (RGH). Bench trials were completed on prototype hardware and provided early verification of the device's ability to withstand repeated cyclic testing. Configurational variants were evaluated and a preferred design concept was established. Silicone rubber (medical grade) was selected as the preferred material for the prosthesis

Technology 2003: Conference Proceedings from the Fourth National Technology Transfer Conference and Exposition, Volume 1

Proceedings from symposia of the Technology 2003 Conference and Exposition, December 7-9, I993, Anaheim, CA. Volume 1 features the Plenary Session and the Plenary Workshop, plus papers presented in Advanced Manufacturing, Biotechnology/Medical Technology, Environmental Technology, Materials Science, and Power and Energy

Vitreo-retinal eye surgery robot : sustainable precision

Vitreo-retinal eye surgery encompasses the surgical procedures performed on the vitreous humor and the retina. A procedure typically consists of the removal of the vitreous humor, the peeling of a membrane and/or the repair of a retinal detachment. Vitreo-retinal surgery is performed minimal invasively. Small needle shaped instruments are inserted into the eye. Instruments are manipulated by hand in four degrees of freedom about the insertion point. Two rotations move the instrument tip laterally, in addition to a translation in axial instrument direction and a rotation about its longitudinal axis. The manipulation of the instrument tip, e.g. a gripping motion can be considered as a fifth degree of freedom. While performing vitreo-retinal surgery manually, the surgeon faces various challenges. Typically, delicate micrometer range thick tissue is operated, for which steady hand movements and high accuracy instrument manipulation are required. Lateral instrument movements are inverted by the pivoting insertion point and scaled depending on the instrument insertion depth. A maximum of two instruments can be used simultaneously. There is nearly no perception of surgical forces, since most forces are below the human detection limit. Therefore, the surgeon relies only on visual feedback, obtained via a microscope or endoscope. Both vision systems force the surgeon to work in a static and non ergonomic body posture. Although the surgeon’s proficiency improves throughout his career, hand tremor will become a problem at higher age. Robotically assisted surgery with a master-slave system can assist the surgeon in these challenges. The slave system performs the actual surgery, by means of instrument manipulators which handle the instruments. The surgeon remains in control of the instruments by operating haptic interfaces via a master. Using electronic hardware and control software, the master and slave are connected. Amongst others, advantages as tremor filtering, up-scaled force feedback, down-scaled motions and stabilized instrument positioning will enhance dexterity on surgical tasks. Furthermore, providing the surgeon an ergonomic body posture will prolong the surgeon’s career. This thesis focuses on the design and realization of a high precision slave system for eye surgery. The master-slave system uses a table mounted design, where the system is compact, lightweight, easy to setup and equipped to perform a complete intervention. The slave system consists of two main parts: the instrument manipulators and their passive support system. Requirements are derived from manual eye surgery, conversations with medical specialists and analysis of the human anatomy and vitreo-retinal interventions. The passive support system provides a stiff connection between the instrument manipulator, patient and surgical table. Given the human anatomical diversity, presurgical adjustments can be made to allow the instrument manipulators to be positioned over each eye. Most of the support system is integrated within the patient’s headrest. On either the left or right side, two exchangeable manipulator-support arms can be installed onto the support system, depending on the eye being operated upon. The compact, lightweight and easy to install design, allows for a short setup time and quick removal in case of a complication. The slave system’s surgical reach is optimized to emulate manually performed surgery. For bimanual instrument operation, two instrument manipulators are used. Additional instrument manipulators can be used for non-active tools e.g. an illumination probe or an endoscope. An instrument manipulator allows the same degrees of freedom and a similar reach as manually performed surgery. Instrument forces are measured to supply force feedback to the surgeon via haptic interfaces. The instrument manipulator is designed for high stiffness, is play free and has low friction to allow tissue manipulation with high accuracy. Each instrument manipulator is equipped with an on board instrument change system, by which instruments can be changed in a fast and secure way. A compact design near the instrument allows easy access to the surgical area, leaving room for the microscope and peripheral equipment. The acceptance of a surgical robot for eye surgery mostly relies on equipment safety and reliability. The design of the slave system features various safety measures, e.g. a quick release mechanism for the instrument manipulator and additional locks on the pre-surgical adjustment fixation clamp. Additional safety measures are proposed, like a hard cover over the instrument manipulator and redundant control loops in the controlling FPGA. A method to fixate the patient’s head to the headrest by use of a custom shaped polymer mask is proposed. Two instrument manipulators and their passive support system have been realized so far, and the first experimental results confirm the designed low actuation torque and high precision performance