Percutaneous needle insertions are commonly performed for diagnostic and therapeutic purposes as an effective alternative to more invasive surgical procedures. However, the outcome of needle-based approaches relies heavily on the accuracy of needle placement, which remains a challenge even with robot assistance and medical imaging guidance due to needle deflection caused by contact with soft tissues. In this paper, we present a novel mechanics-based 2D bevel-tip needle model that can account for the effect of nonlinear strain-dependent behavior of biological soft tissues under compression. Real-time finite element simulation allows multiple control inputs along the length of the needle with full three-degree-of-freedom (DOF) planar needle motions. Cross-validation studies using custom-designed multi-layer tissue phantoms as well as heterogeneous chicken breast tissues result in less than 1mm in-plane errors for insertions reaching depths of up to 61 mm, demonstrating the validity and generalizability of the proposed method.

Malaria is a worldwide scourge, and the broad deployment of an effective vaccine would improve the lives of millions of people. A vaccine based on Plasmodium falciparum (PfSPZ) sporozoites extracted from the salivary glands of infected mosquitoes shows significant promise. However, the large-scale industrial production of PfSPZ-based vaccines will benefit from automation of the key step of extracting sporozoites from mosquito salivary glands that is currently performed by manual microdissection. In this work, we demonstrate a robotic system prototype for extracting salivary glands from mosquitoes to streamline vaccine production and reduce the need for operators. In the proposed system, mosquitoes are decapitated in an automated robotic pick-place-decapitate process, then a squeezer apparatus extracts mosquito salivary glands from the body. Mosquito detection and body part localization are performed by computer vision methods. The software allows system operation in simulation and on the robotic hardware, which facilitates subsystem development and integration. Experiments show encouraging results with success rates of 93% in robotic mosquito manipulation and 87.1% in salivary gland extraction. The system has the potential to improve the efficiency of PfSPZ vaccine production with significant gains in throughput and reduction in training times for a highly deskilled initial manual step. Further, this system is expected to pave the way for a more mature future system.

Lumbar injection is an image-guided procedure performed manually for diagnosis and treatment of lower back pain and leg pain. Previously, we have developed and verified an MR-Conditional robotic solution to assisting the needle insertion process. Drawing on our clinical experiences, a virtual remote center of motion (RCM) constraint is implemented to enable our robot to mimic a clinician’s hand motion to adjust the needle tip position in situ. Force and image data are collected to study the needle behavior in gel phantoms during this motion, and a mechanics-based needle-tissue interaction model is proposed and evaluated to further examine the underlying physics. This work extends the commonly-adopted notion of an RCM for flexible needles, and introduces new motion parameters to describe the needle behavior. The model parameters can be tuned to match the experimental result to sub-millimeter accuracy, and this proposed needle manipulation method presents a safer alternative to laterally translating the needle during in situ needle adjustments.

This article presents a new cable-driven underactuated robotic gripper, called TWISTER Hand. It is designed for adaptable grasping of objects in different shapes, weights, sizes, and textures. Each finger of the gripper is made of a compliant and continuum mechanism inspired by an origami design. This design is converted into a computer-aided design (CAD) model and 3-D printed using flexible and rigid polymer composite materials. Two CAD modeling methods for this design are compared in terms of structural stiffness and durability in the printed outcomes. For each design, two soft materials are used for preliminary evaluation of the material effect in these properties. The best combination of the model and material is selected to fabricate the three fingers of the robotic gripper. Each finger has a single cable routed along the structure. All three cables are tied and actuated simultaneously using a single servo motor to generate closing and opening motions in the gripper. TWISTER Hand's adaptable grasping capability is tested using 36 different objects. The robot's grasping performance under object pose uncertainties is also experimentally tested and analyzed. This compact fully integrated gripper can be attached to a robotic arm for various manipulative tasks.