Search

In minimally invasive surgery (MIS), a number of instruments are inserted into the surgical cavity via the trocar(s), which makes the surgical site crowded and instruments tend to fence with each other. In addition, the motion of the endoscope is restricted by the trocar, which limits the field of view of the endoscope. To alleviate these problems, magnetic anchored and guided systems (MAGSs) have been proposed. Conventional MAGSs are built from rigid materials with small actuators and sensors. As a result, these MAGSs tend to be heavy, complex, difficult to make, and costly. In this article, we first present a soft-bodied MAGS endoscope weighing 13 g, which is made up of printable silicon rubber with embedded magnets and a camera module. The usage of soft 3-D printable material significantly reduces the complexity of the MAGS endoscope. The soft-bodied MAGS endoscope can be anchored and steered by an external magnet controlled by a serial-link robot arm. The kinematic modeling of the soft-bodied MAGS endoscope is developed. Visual servo based automatic instruments tracking of the soft-bodied MAGS endoscope is achieved for the first time. Experimental results validate that the soft-bodied MAGS endoscope can guide surgical instruments, showing its high potentials in MIS.

In stereotactic brain biopsy, operating the needle accurately and taking the biopsy specimen safely are two major challenges for ensuring the success of the surgical procedure. Considering this fact, surgical robots offering high accuracy and precision have been developed for neurosurgery including brain biopsy. Typical brain biopsy robots are only commanded to adjust the needle's pose before inserting the needle manually by a neurosurgeon. In the literature, there exists no robotic system that is competent to complete the needle insertion task autonomously. To move a step forward, a novel biopsy module for brain biopsy is first designed and fabricated in this paper. The biopsy module can be automated to complete a series of tasks such as inserting the needle, generating and controlling the aspiration pressure for specimen acquisition, and rotating the cannula for side-cutting. The biopsy module is further integrated with a cost-effective and lightweight UR5 robot and an optical tracking system to improve the autonomy, leading to a stereotactic neuronavigation system. Kinematic relationships of the involved elements are established via a calibration process. A quadratic programming based approach equipped with a virtual potential field method is implemented to safely control the robot with joint-limit avoidance and obstacle avoidance capabilities. The experimentation of the brain biopsy robot is performed, demonstrating that the developed robotic system has potential applicability in the brain biopsy surgery.

To overcome the detrimental effects of LiFePO 4 on the tap density and volumetric energy density accompanied by conventional carbon-based additives, C-LiFePO 4 /graphene was successfully prepared via hydrothermal synthesis, followed by heat treatment, and by substitution of superior conductive graphene nanosheets for some conventional carbon. The reduction of graphite oxide and the synthesis of LiFePO 4 were carried out simultaneously in mixed ethylene glycol/water medium, facilitating desirable compatibility and architecture of LiFePO 4 particles and graphene nanosheets. Due to the synergism of thin carbon coating and graphene matrix with low fraction on the basis of complementary advantages, C-LiFePO 4 /graphene exhibits superior high-rate performance and favorable energy density, which with a unique structural and geometrical feature that LiFePO 4 /C nanorods embedded in a matrix built of interweaved graphene nanosheets. The dual coatings exert a significantly energetic impact on the electronic conductivity and lithium ion transport, thus novel composite presented excellent electrochemical properties, which was achieved with reversible capacities of 100 mAh/g at 20 C and 80 mAh/g at 50 C, while preserving a high tap density of 1.76 g/cm 3 .