Godwin Ponraj

Endotrachealintubation is a common medical practice for patients requiring upper airway management. An important parameter while performing intubation is the depth of insertion of the tube. However, most current solutions rely on vision-based feedback for successfully performing remote intubation. We propose a novel application of chip-less RF sensing technology to identify the intubation tube from the exterior and serve as an additional feedback modality, independent of the visual aid. We used printable silver conductive ink to fabricate flexible RF antennas to be deployed on the Endotracheal (ET) intubation tubes. An interrogating antenna, connected to a network analyzer, placed on top of the neck can identify the RF antenna inside the trachea during intubation in real-time. A prototype design was developed and tested with various wireless channel mediums (air, water, phantom models, and duck neck). Seven human subjects were involved in another experiment that used human fingers as a wireless medium between the antennas. Experimental results show that the proposed method can identify the presence of ET tubes by registering a significant change in the return loss magnitude (2.21 dB in phantom model and an average of 1.16 dB in human experiments) across all the mediums. The proposed sensing solution can be used as a viable feedback parameter for robotic control systems that aim to automate intubation with or without visual feedback.

The steady rise of deployable structures and mechanisms based on kirigami and origami principles has brought about design innovations that yield flexible and lightweight robots. These robots are designed based on desirable locomotion mechanisms and often incorporate additional materials to support their flexible structure to enable load-bearing applications and considerable efficient movement. One tetherless way to actuate these robots is via the use of magnets. This paper incorporates magnetic actuation and kirigami structures based on the lamina emergent mechanism (LEM). Three designs of magnetic-actuated LEMs (triangular prism, single LEM (SLEM), alternating mirror dual LEM (AMDLEM)) are proposed, and small permanent magnets are attached to the structures’ flaps or legs that rotate in response to an Actuating Permanent Magnet (APM) to yield stick-slip locomotion, enabling the robots to waddle and crawl on a frictional surface. For preliminary characterization, we actuate the three designs at a frequency of 0.6 Hz. We observed the triangular prism, SLEM, and AMDLEM prototypes to achieve horizontal speeds of 4.3 mm/s, 10.7 mm/s, and 12.5 mm/s on flat surfaces, respectively. We further explore how changing different parameters (actuation frequency, friction, leg length, stiffness, compressibility) affects the locomotion of the different mechanisms.

Intra-abdominal pressure (IAP) is closely correlated with intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) diagnoses, indicating the need for continuous monitoring. Early intervention for IAH and ACS has been proven to reduce the rate of morbidity. However, the current IAP monitoring method is a tedious process with a long calibration time for a single time point measurement. Thus, there is the need for an efficient and continuous way of measuring IAP. Herein, a stretchable capacitive pressure sensor with controlled microstructures embedded into a cylindrical elastomeric mold, fabricated as a pressure sensing sleeve, is presented. The sensing sleeve can be readily deployed onto intrabody catheter balloons for pressure measurement at the site. The thin and highly conformable nature of the pressure sensing sleeve captures the pressure change without hindering the functionality of the foley catheter balloon.

Omnidirectional steerable forceps in keyhole procedures provide significant advantages in assisting medical practitioners with better motion coordination, improved dexterity, precision control, and reachability. However, most existing forceps lack the sense of interactive proprioception, imposing physical and cognitive challenges to the medical practitioners during manipulation. Herein, we report handheld steerable surgical forceps with two degrees-of-freedom equipped with skin-like soft stretchable strain sensors to determine the orientation and improve the perception. The performance of omnidirectional forceps integrated with sensory skin is characterized. Due to the reduced number of mechanical parts in the forceps by virtue of parallel continuum joints, the direct translation of motion from the proximal to the distal end is achieved. The distal parallel flexible joint enables a bending angle up to 40° and a bending radius of 7.5 mm. The hydrogel-based silver nanowire sensors mounted on the forceps like a stretchable skin show a maximum gauge factor of 11.8 under 80% strains. A mathematical model is developed to determine the tooltip orientation. The developed model validated with visual tracking shows 90–97% accuracy for angular displacements up to 30° in all directions. Assisting medical practitioners in a clinical environment is demonstrated in a cadaveric setting by providing proprioceptive information of the tooltip through OFISS.

Wearable devices are gaining recognition for their use as a biosensor platform. Electrical impedance tomography (EIT) is one of the sensing techniques that utilizes wearable sensors as its primary data acquisition system. It measures the impedance or resistance at the peripheral (skin) level and calculates the conductivity distribution throughout the body. Even though the technology has existed for several decades, modern-day EIT devices are still costly and bulky. The paper proposes a novel low-cost kirigami-based wearable device that has soft PEDOT: PSS electrodes for sensing skin impedances. Simulation results show that the proposed kirigami structure for the bracelet has a large deformation during actuation while experiencing relatively lower stress. The paper also presents a comparative study on a few machine learning algorithms to classify hand gestures, based on the measured skin impedance. The best classification accuracy (91.49%) was observed from the quadratic support vector machine (SVM) algorithm with 48 principal components.

Bimanual telemanipulation is vital for facilitating robots to complete complex and dexterous tasks that involve two handheld objects under teleoperation scenarios. However, the bimanual configuration introduces higher complexity, dynamics, and uncertainty, especially in those uncontrolled and unstructured environments, which require more advanced system integration. This paper presents a bimanual robotic teleoperation architecture with modular anthropomorphic hybrid grippers for the purpose of improving the telemanipulation capability under unstructured environments. Generally, there are two teleoperated subsystems within this architecture. The first one is the Leap Motion Controller and the anthropomorphic hybrid robotic grippers. Two 3D printed anthropomorphic hybrid robotic grippers with modular joints and soft layer augmentations are designed, fabricated, and equipped for telemanipulation tasks. A Leap Motion Controller is used to track the motion of two human hands, while each hand is utilized to teleoperate one robotic gripper. The second one is the haptic devices and the robotic arms. Two haptic devices are adopted as the master devices while each of them takes responsibility for one arm control. Based on such a framework, an average RMSE (root-mean-square-error) value of 0.0204 rad is obtained in joint tracking. Nine sign-language demonstrations and twelve object grasping tasks were conducted with the robotic gripper teleoperation. A challenging bimanual manipulation task for an object with 5.2 kg was well addressed using the integrated teleoperation system. Experimental results show that the proposed bimanual teleoperation system can effectively handle typical manipulation tasks, with excellent adaptabilities for a wide range of shapes, sizes, and weights, as well as grasping modes.

Origami-based flexible, compliant, and bio-inspired robots are believed to permit a range of medical applications within confined environments. In this article, we experimentally demonstrated an origami-inspired deployable surgical retractor with the controllable stiffness mechanism that can facilitate safer instrument–tissue interaction in comparison to their rigid counterparts. When controllable negative-pressure is applied to the jammed origami retractor module, it becomes more rigid, increasing its strength. To quantify origami-modules strength further, we demonstrated performances of retractor based on the Daler–Rowney Canford paper (38 grams per square meter (gsm)) and sandpaper of 1000 grit. Experiments on the proposed retractor prototype elucidated sandpaper-based retractor can outperform paper-38-gsm retractor for facelift incision with the width of more than 9 cm. Though 38 gsm Canford paper comprised of thin layers, 16 times lesser in thickness than sandpaper, experiments proved its comparable layer jamming (LJ) performance. We leverage the advantage of the LJ mechanism to tune retractor stiffness, allowing the instrument to hold and separate a facelift incision to mitigate the likelihood of surgical complications. The retractor is equipped with a custom-made printed conductive ink-based fabric piezoresistive tactile sensor to assist clinicians with tissue-retractor interaction force information. The proposed sensor showed a linear relationship with the applied force and has a sensitivity of 0.833 N−1. Finally, cadaver experiments exhibit an effective origami-inspired surgical retractor for assisting surgeons and clinicians in the near future.

Tactile sensing is an emerging technological advancement in surgical robotics in order to probe interactions between confined tissue environments and instruments based on touch information. The tactile sense can assist in improving the efficiency of the whole practice and hence enhance precision, control, and safety during surgery. This paper demonstrates a distinct proof-of-concept therapeutic device equipped with a soft tactile sensor. The tactile sensor was custom-made using flexible piezoresistive materials and conductive ink, wrapped with a biocompatible hydrogel polymer matrix for safer human–tissue interactions. The proposed tactile sensor was then calibrated and its performance was compared with gold standard sensors. It was further tested with a continuous force (5 N) for an extended period of time (about 6 h) to address robustness and repeatability. The sensor showed a sensitivity of 0.833 N−1 and a drift of ≤1%. Successful cadaver experiment demonstrates the efficiency of tactile sensing assistance to clinicians.