While wearable robots that utilize intrinsically soft materials for actuation offer enhanced safety and biological compatibility, the challenges of sensing and control significantly affect their performance. The control problem in such systems is inherently complex, and the inclusion of 'softness' introduces additional nonlinearities, hysteresis, and uncertainties. Furthermore, the effectiveness of control strategies is highly dependent on sensor selection and integration, which presents its own challenges. Most robotic systems require separate sensors for control purposes. In this study, a new sensing and control scheme are introduced for soft wearable robots, leveraging the intrinsic soft-sensing capability of fluidic filament actuators without adding computational complexity. This method enables simultaneous sensing and actuation with$\mathbf{9 6 \%}$position accuracy, even under physical disturbances. This approach is demonstrated with a soft assistive device for elbow flexion/extension, achieving 70.5% tracking accuracy and a 0.09s response delay to human intention, ensuring the system provides minimal resistance when assistance is not needed, while delivering the required support when necessary.

Aneurysms, balloon-like bulges in blood vessels, present a significant health risk due to their potential to rupture, leading to life-threatening internal bleeding. Current treatments often involve delivering embolic materials or metal coils to fill these bulges, occluding them from the pressure of blood flow. However, clinical micro-catheters that deploy embolic materials used today face limitations, primarily their rigidity and the lack of active control over the bending tip of the catheter. This paper introduces a new soft micro-robotics catheter, with diameter of only 0.8 mm, equipped with a hollow channel. With this new design, the new device can induce bending motions at its tip for active steerability to reach desired aneurysm targets and then perform the delivery of embolic materials and tools. To enhance the control and precise navigation during procedures, a robust mathematical model and image processing techniques are also introduced and validated. Experiments are also performed to characterise and validate the model’s accuracy and the steerability and navigation capabilities of the new micro-catheter.

Following biology's lead, soft robotics has emerged as a perfect candidate for actuation within complex environments. While soft actuation has been developed intensively over the last few decades, soft sensing has so far slowed to catch up. A largely unresearched area is the change of the soft material properties through prestress to achieve a degree of mechanical sensitivity tunability within soft sensors. Here, a new 3D force sensor which employs novel hydraulic filament artificial muscles capable of in-situ sensitivity tunability is introduced. Using a neural network (NN) model, the new soft 3D sensor can precisely detect external forces based on the change of the hydraulic pressures with error of$\sim 1.0, \sim 1.3$, and$\sim 0.94$% in the$\text{x, y}$, and z-axis directions, respectively. The sensor is also able to sense large force ranges, comparable to other similar sensors available in the literature. The sensor is then integrated into a soft robotic surgical arm for monitoring the tool-tissue interaction during an ablation process.

Atrial fibrillation (AF) is mostly treated via robotic catheter-based cardiac ablation procedures. Over the last few decades, cables or tendon mechanisms are at the core of available cardiac catheters. Despite advances, the use of cables often results in considerable force loss, nonlinear hysteresis, and control challenges. Most catheters are not equipped with force sensing, which increases the risk of the ablation process and decreases their efficacy in clinical settings. In addition, current catheters have a poor user interface and therefore the ablation process requires skilled or trained surgeons to steer the complex motion of the catheter tip within the heart chambers. To improve the cardiac ablation procedure, a new robotic catheter that has the ability to extend its working space without moving its flexible body and a real-time force sensor for safe operation is highly desired. In this work, a new handheld and soft robotic catheter for AF ablation is introduced. The new device consists of several improved components such as a soft manipulator for navigation and bending motion, an ergonomic handheld controller, and a soft force sensor for monitoring tool-tissue contact. The design, modeling, and fabrication of the device are presented and followed by experimental characterizations and ex-vivo validation.

There is an increasing interest in soft robotic grippers as they exhibit an ability to grip objects of differing shapes, sizes, textures, and even deformable materials, all of which present a difficult challenge to traditional rigid grippers. An ideal soft gripper would exhibit universal gripping with high gripping force and consists of low-cost materials with simple fabrication processes. This paper investigates the development of a strong and scalable hydraulic soft tubular gripper (HSTG) using facile fabrication method and low-cost materials. The HSTG which consists of a single long hydraulically actuated artificial muscle, soft 3D printed element, and commercial weaving yarn can expand and contract its orifice to grasp objects using a miniature hydraulic syringe. Grasping experiments show that the new HSTG can successfully grasp convex, nonconvex, and flat objects as well as the ones with cavity. The soft gripper uniquely exhibits high normal contact force at minimal pressure and energy use due to the nature of its working principle. A 26 g HSTG can produce at least 40 N of gripping force, can hold at least 88 N in external gripping mode (~346 times of its weight), 0.34 N in internal mode, and 1.74 N in suction gripping mode. The design and mechanical properties of its components can be fine-tuned to produce tailored performance for different grasping tasks.

Heart rhythm disorders are becoming increasingly prevalent with population aging. Atrial fibrillation ablation (AFA) is a procedure used to treat an irregular heart rhythm (arrhythmia) that starts in the heart's upper chambers. The AFA works by scarring or destroying heart tissue to disrupt aberrant conduction pathways causing the arrhythmia. In hospital cardiac units, a flexible catheter with integrated metal electrode is currently used for the AFA procedure. Despite advances, existing cardiac catheter tips are driven by cable mechanisms which are associated with high nonlinear hysteresis and force loss. In addition, they are also limited to rigid components which require multiple actuators to control the bending tip to reach the complex anatomical corners of the heart. This paper introduces a new soft hydraulic catheter that can achieve bidirectional bending motion via a single soft artificial muscle. The new catheter is also equipped with a portable handle as an ergonomic control interface. To validate the design concept, various prototypes are fabricated and tested including bending angles and generated force capability. Mathematical models for the bending arm are also developed and experimentally validated. The new soft catheter will enable rapid and precise manipulation to reach any target within the cardiac chambers, offering more rapid and focused ablation therapy to improve patient outcomes.

Accurate motion control of surgical robots is critical for the efficiency and safety of both state-of-the-art teleoperated robotic surgery and the ultimate autonomous robotic surgery. However, fine motion control for a flexible endoscopic surgical robot is highly challenging because of the shape-dependent and speed-dependent motion hysteresis of tendon-sheath mechanisms (TSMs) in the long, tortuous, and dynamically shape-changing robot body. Aiming to achieve precise closed-loop motion control, we propose a small and flexible sensor to directly sense the large and sharp rotations of the articulated joints of a flexible endoscopic surgical robot. The sensor-a Fiber Bragg Grating (FBG) eccentrically embedded in a thin and flexible epoxy substrate-can be significantly bent with a large bending angle range of [-62.9°, 75.5°] and small bending radius of 6.9 mm. Mounted in-between the two pivot-connected links of a joint, the sensor will bend once the joint is actuated, resulting in the wavelength shift of the FBG. In this study, the relationship between the wavelength shift and the rotation angle of the joint was theoretically modeled and then experimentally verified before and after the installation of the sensor in a robotic endoscopic grasper. The sensor, with the calibrated model, can track the rotation of the robotic joint with an RMSE of 3.34°. This small and flexible sensor has good repeatability, high sensitivity (around 147.5 pm/degree), and low hysteresis (7.72%). It is suitable for surgical robots and manipulators whose articulated joints have a large rotation angle and small bending radius.

Perforations in flexible endoscopy are life-threatening. Defect closure or suturing in flexible endoscopy has long been a critical challenge due to the confined space of the access routes and surgical sites, high dexterity and force demands of suturing tasks, as well as critical size and strength requirements of wound closure. This paper introduces a novel robotic suturing system for flexible endoscopic surgery. This system features a flexible, through-the-scope, five-degree-of-freedom robotic suturing instrument. This instrument allows the surgeon to endoscopically manipulate a needle via a master console to create running stitches and knots in flexible endoscopy, which is not possible with existing devices. Successful ex-vivo trials were conducted inside porcine colons to show how surgical stitches and knots can be endoscopically created and secured in a completely new way. This new technology will change the way how surgeons close defects or perforations in flexible endoscopic surgery.

Accurate haptic feedback is a critical challenge for surgical robots, especially for flexible endoscopic surgical robots whose transmission systems are Tendon-Sheath Mechanisms (TSMs) with highly nonlinear friction profiles and force hysteresis. For distal end haptic sensing of TSMs, this paper, for the first time, proposes to measure the compression force on the sheath at the distal end so that the tension force on the tendon, which equals the compression force on the sheath, can be obtained. A new force sensor, i.e., a nitinol tube attached with an optical Fiber Bragg Grating (FBG) fiber, is proposed to measure the compression force on the sheath. This sensor, with similar diameter and configuration (hollow) as the sheath, can be compactly integrated with TSMs and surgical end-effectors. In this paper, mechanics analysis and verification tests are presented to reveal the relationship between the tension force on the tendon and the compression force on the sheath. The proposed force sensor was calibrated in tests with a sensitivity of 24.28 pm/N and integrated with a tendon-sheath driven grasper to demonstrate the effectiveness of the proposed approach and sensor. The proposed approach and sensor can also be applied for a variety of TSMs-driven systems, such as robotic fingers/hands, wearable devices, and rehabilitation devices.

Obesity is defined as an unhealthy excess of body fat, which increases the risks of medical illness and premature mortality. There are multiple health risks linked to obesity such as heart disease and stroke, high blood pressure, diabetes, cancers, gallbladder disease and gallstones, osteoarthritis, gout, and breathing problems like sleep apnea, and asthma. Intragastric balloons (IGBs) have become an efficient and less invasive method for obesity treatment. However, the use of traditional IGBs requires complex insertion tools and flexible endoscopes to place and remove the balloon inside patient's stomach. This causes abdominal discomfort, nausea, vomiting, and gastric mucous damage. To overcome these limitations, we designed a novel magnetic soft capsule robot for obesity treatment with magnetically actuated inflatable IGB. The balloon is made from a thin, flexible, biocompatible material, and is inflated to a desired volume using biocompatible effervescent chemicals. Instead of using complex deflation mechanism, a biodegradable material is developed to automatically deflate the balloon after a predetermined period of treatment. In addition, multiple capsules can be simultaneously swallowed. As the source of actuation is provided via external magnetic fields, the magnetic soft capsule size can be significantly reduced with no limitations on the power consumption. A prototype of magnetic soft capsule is developed. Experiments are carried out to demonstrate the effectiveness of the proposed approach.