Colorectal cancer is a serious threat to human health. Colonoscopy is the most effective procedure for the inspection of colorectal cancer. However, traditional colonoscopy may cause pain, which can lead to the patient’s fear of colonoscopy. The use of active-motion colonoscopy robots is expected to replace traditional colonoscopy procedures for colorectal cancer screening, without causing pain to patients. This paper proposes an inchworm-like soft colonoscopy robot based on a rubber spring. The motion mechanism of the robot consists of two anchoring units and an elongation unit. The elongation unit of the robot is driven by 3 cables during contraction and by its inherent elasticity during extension. The balloon is selected as the anchoring mechanism of the robot. It has soft contact with the colon and will not damage the colon wall, which means no discomfort is caused. The elastic force test of the rubber spring shows that the elongation unit of the robot has sufficient restorative force to drive the robot to move forward and backward. The influence of the balloon’s expansion size on the dexterity of the robot head is analyzed, and the functions of the balloons are expounded. The balloon can not only assist the robot in its locomotion but also assist the robot to perform a better inspection. The robot can move successfully in a horizontal, straight, and inclined isolated pig colon, showing great clinical application potential.

As an irreplaceable element for obtaining airflow information in many engineering scenarios, airflow sensors have gained increasing attention across the fields of aerospace engineering, environmental engineering, sustainable energy exploitation, meteorology research, and so on. As one of the mainstream airflow sensing principles, piezoresistive airflow velocity sensors have experienced rapid growth over the years, while effective vector airflow sensors with the ability of detecting both airflow velocity and direction based on the piezoresistive principle are scarce. Here, on the basis of our developed piezoresistive airflow velocity sensors based on pressure loading mode, we design an array of these sensors and propose a corresponding explicit algorithm for simultaneous detection of airflow velocity and direction. This sensor array configuration enables an automatic recognition function of the quadrant of incoming airflow, which can significantly simplify the reverse calculation of airflow information compared with conventional vector airflow sensors. The experimental results demonstrate the decent performance of this sensor array for identifying both airflow velocity and direction. This study not only fills the gap between our developed airflow velocity sensor and the ability of detecting airflow direction but also presents a simple and universal array-based strategy for vector airflow sensing, which could be widely applied in airflow sensors based on other principles.

The incidence rate of colorectal cancer ranks third among all cancers, which is a serious threat to human health [1]. Endoscopic submucosal dissection (ESD) is an effective endoscopic surgical method for early gastric and colorectal cancers [2]. However, ESD is a procedure with high technical requirements, which brings a higher risk of complications and requires long training for clinicians [3]. Robots are expected to simplify ESD procedures and reduce training time. But there is no standard flexible robotic endoscope at present. Soft robots can potentially offer better adaptability and safer interaction with the environment. As such, they hold great potential in solving the technical challenges of the current minimally invasive surgery (MIS), which are difficult to be solved by rigid robots. Here we demonstrate an inflatable robot which is largely made of flexible plastic film. In the deflated state, it is easy to collapse, fold and roll into a small size, promising easier delivery by a carrier endoscope to the proximal colon. After reaching the target site, the robot is inflated and the surgery is performed. This work is based on the inflatable Cyclops robot [4][5]. However, small folded hydraulic actuators are used to replace the contraction-based pouch actuators used in [5], which have a larger size. The anchor points of the cables with planar layout replace the spatial layout in [4], which reduces the axial size of the robot, allowing it to pass through the colon bends more easily. Folded actuators made of an airbag are flexible and adaptable [6]. The actuator volume is very small under deflated condition, but it can achieve large deformation after inflation. The proposed actuator uses a folded chamber to pull the cable to produce a large displacement without the need of displacement amplification mechanisms. In the deflated state, the length of soft scaffold of the robot is about 65mm, and the overall size of the robot is 100mm ×6mm×20mm. In the state of inflation, the soft scaffold deploys into a hexagonal prism with a length of 55mm, and the bottom side length of the prism is 30mm. The tip workspace of the robot can reach 40mm in all three directions of the local coordinate system.

No abstract