Minimally Invasive Surgery has advanced surgical practice, yet early-stage gastrointestinal cancer treatment remains challenging. Endoscopic Submucosal Dissection offers a solution but faces maneuverability constraints in complex anatomical environments. This paper presents a novel inflatable soft robotic manipulator with a biocompatible thin-film shell and tendon-driven antagonistic actuation. The robot remains compact at 6.5 mm of diameter, expanding to 11.7 mm to enhance stiffness for force exertion and precise manipulation. Featuring two decoupled wrists with four degrees of freedom, it enables dexterous motion for advanced endoscopic procedures. The study details design, fabrication, actuation modeling, workspace evaluation, and simulated retraction experiments in a constrained environment. Results demonstrate high repeatability, high master-slave control accuracy, effective workspace utilization, and feasibility for endoluminal applications, enhancing robotic-assisted endoscopic procedures with improved dexterity and adaptability under soft actuation constraints.

This paper presents a soft Cable-Driven Parallel Robot for gastrointestinal surgery. The robot consists of an inflatable scaffold and a hydraulic variable stiffness end-effector and features six degrees of freedom. Experiments involving passage through a colon model, knot tying, and retraction have demonstrated its flexibility and the concept of navigating through the colon in a soft configuration, then increasing rigidity at the lesion site to collaborate with the endoscope in performing surgery. Meanwhile, the robot can sense the contact force through hydraulic pressure variations within the end-effector shaft, providing haptic feedback, which reduces the effects of Coulomb friction. When using the robot to calculate pressing forces, it achieved accuracy with a mean error of 0.051 N and a standard deviation (STD) of 0.066 N. For lifting forces, it achieved a mean error of 0.066 N and a STD of 0.083 N. These results demonstrate the potential of the robot for tissue palpation applications.

This paper presents a novel pneumatic pouch sensor, designed to mount on a colonoscope, that can effectively estimate the contact forces with the environment. The pouch sensor was designed to maximize the sensing range, and it was fabricated using a 2D laser welding technique from our track record. A flow compensation (FC) algorithm was introduced to improve the accuracy of the sensor in the presence of static load. The proposed system can reliably measure external forces up to 9.5 N with high repeatability. The system allows discriminating between different levels of force which are typically associated with increasing patient discomfort in colonoscopy: low (0-4 N), medium (4-6 N), and high (>6 N). This system achieves over 80% accuracy in comparison to the ground truth under steady state conditions (P ≤ 0.05) and maintains over 68% accuracy in dynamic scenarios.

In this article, we investigate the model based position control of soft hydraulic actuators arranged in an an-tagonistic pair. A dynamical model of the system is constructed by employing the port-Hamiltonian formulation. A control algorithm is designed with an energy shaping approach, which accounts for the pressure dynamics of the fluid. A nonlinear observer is included to compensate the effect of unknown external forces. Simulations demonstrate the effectiveness of the proposed approach, and experiments achieve positioning accuracy of 0.043 mm with a standard deviation of 0.033 mm in the presence of constant external forces up to 1 N.

In Robot-assisted Minimally Invasive Surgery (RMIS), the estimation of the pose of surgical tools is crucial for applications such as surgical navigation, visual servoing, autonomous robotic task execution and augmented reality. A plethora of hardware-based and vision-based methods have been proposed in the literature. However, direct application of these methods to RMIS has significant limitations due to partial tool visibility, occlusions and changes in the surgical scene. In this work, a novel keypoint-graph-based network is proposed to estimate the pose of texture-less cylindrical surgical tools of small diameter. To deal with the challenges in RMIS, keypoint object representation is used and for the first time, temporal information is combined with spatial information in keypoint graph representation, for keypoint refinement. Finally, stable and accurate tool pose is computed using a PnP solver. Our performance evaluation study has shown that the proposed method is able to accurately predict the pose of a textureless robotic shaft with an ADD-S score of over 98%. The method outperforms state-of-the-art pose estimation models under challenging conditions such as object occlusion and changes in the lighting of the scene.

Incorrectly sized balloon catheters can lead to increased post-surgical complications, yet even with preoperative imaging, correct selection remains a challenge. With limited feedback during surgery, it is difficult to verify correct deployment. We propose the use of integrated impedance measurements and Electrical Impedance Tomography (EIT) imaging to assess the deformation of the balloon and determine the size and shape of the surrounding lumen. Previous work using single impedance measurements, or pressure data and analytical models, whilst demonstrating high sizing accuracy, have assumed a circular cross section. Here we extend these methods by adding a multitude of electrodes to detect elliptical and occluded lumen and obtain EIT images to localise deformations. Using a 14 Fr (5.3 mm) catheter as an example, numerical simulations were performed to find the optimal electrode configuration of two rings of 8 electrodes spaced 10 mm apart. The simulations predicted that the maximum detectable aspect ratio decreased from 0.9 for a 14mm balloon to 0.5 at 30mm. The sizing and ellipticity detection results were verified experimentally. A prototype robotic balloon catheter was constructed to automatically inflate a compliant balloon while simultaneously recording EIT and pressure data. Data were collected in experiments replicating stenotic vessels with an elliptical and asymmetrical profile, and the widening of a lumen during angioplasty. After calibration, the system was able to correctly localise the occlusion and detect aspect ratios of 0.75. EIT images further localised the occlusion and visualised the dilation of the lumen during balloon inflation.

Soft robotic systems offer benefits over traditional rigid systems through reduced contact trauma with soft tissues and by enabling access through tortuous paths in minimally invasive surgery. However, the inherent deformability of soft robots places both a greater onus on accurate modelling of their shape, and greater challenges in realising intraoperative shape sensing. Herein we present a proprioceptive (self-sensing) soft actuator, with an electrically conductive working fluid. Electrical impedance measurements from up to six electrodes enabled tomographic reconstructions using Electrical Impedance Tomography (EIT). A new Frequency Division Multiplexed (FDM) EIT system was developed capable of measurements of 66 dB SNR with 20 ms temporal resolution. The concept was examined in two two-degree-of-freedom designs: a hydraulic hinged actuator and a pneumatic finger actuator with hydraulic beams. Both cases demonstrated that impedance measurements could be used to infer shape changes, and EIT images reconstructed during actuation showed distinct patterns with respect to each degree of freedom (DOF). Whilst there was some mechanical hysteresis observed, the repeatability of the measurements and resultant images was high. The results show the potential of FDM-EIT as a low-cost, low profile shape sensor in soft robots.

This paper presents a three-tendon actuated continuum robot with an origami backbone to assist the elderly and physically impaired individuals in performing activities of daily living. The proposed design solution is an inherently safe and cost-effective alternative to current assistive robots. The origami backbone based on a variation of the Yoshimura pattern provides controlled deployment of the robot and enables length variation (15 cm - 56 cm) in order to increase the reachable workspace. A pneumatic stiffness mechanism was implemented, increasing the weight bearing capabilities of the continuum robot to 500 g. This new stiffness modulation approach was assessed with the use of several testing rigs. Additionally, the robot is joypad controlled and is easily transportable due to its high packing efficiency of 73% and light weight of 1.3 kg for the main body (including the actuation system). For demonstration of usability studies, the robot was successfully tested at a simulated kitchen terminal and also performed pick and place tasks.