| The new cases of colorectal cancer rank the second among all the new cases of cancer in China in 2020,and the incidence is increasing year by year,making it one of the major diseases affecting human health.Timely intestinal examination is an effective method to prevent colorectal cancer.However,currently,the colonoscopy used for intestinal examination in clinic is generally made of rigid materials,which will cause a strong sense of discomfort to patients when entering the human body,and it is also easy to cause damage to the mucosal tissue of the inner wall of the intestine.Capsule endoscopy as another tool for intestinal examination has the disadvantage of not being able to move autonomously.The soft robot has become a new approach to examine,diagnose and treat intestinal diseases due to its high degree of flexibility and patient-friendly interaction.However,the current researches on soft robots for intestinal detection are almost limited to realize the controlled movement in the intestinal or intestine-like environment and the observation of the intestinal environment,lacking of further auxiliary functions such as collecting samples in the intestine.In this study,two generations of soft robots for intestinal sampling are proposed by combining pneumatic control method and casting molding process.This paper carries out research from the following aspects:(1)Soft robots for intestinal sampling are designed and manufactured.In this paper,two generations of earthworm-like pneumatic intestinal sampling soft robots are proposed.The body part of both generations of the soft robots contains two radial actuators and a axial actuator,which are used to drive the forward and backward motion of soft robots in the intestine.The sampling module of the first-generation intestinal soft robot is a flexible gripper fixed on the front radial actuator,which can realize the directional grabbing of the sample target.The sampling structure of the second-generation intestinal soft robot is composed of a bidirectional flexural mechanism and a sampler,which can realize bidirectional sampling on the intestinal wall.The materials used to fabricate the soft robots have Young’s modulus similar to soft biological tissues in nature and have excellent elasticity,which helps to reduce the discomfort of patients during intestinal sampling.(2)Finite element analysis is carried out for the deformation performance of each actuator of the intestinal sampling soft robots.The finite element simulation of the body part,the gripper,the bidirectional bending mechanism and the sampler of the soft robot is carried out respectively.The results of the finite element simulation are basically consistent with the real effect,which verifies the rationality of the structure.Finally,the relationship between the pressure in the cavity of the actuator and the deformation size is obtained by using several groups of measurement data.(3)The control system of the intestinal sampling soft robot is built,and the related performance of the soft robot is tested through experiments.The principle of the control system is to use the Arduino microcontroller to control the state of relays,so as to control the on-off of air pumps and solenoid valves,and then control the motion of the soft robot.Experiments show that the first-generation intestinal sampling soft robot can carry out controlled movements and grasp objects in rigid pipes,silicone hoses and pipes containing mucus.The maximum moving speed of the intestinal sampling soft robot is up to 14.0 cm/min,and the ultimate weight that the soft robot can grab is 220 g.Finally,the second-generation intestinal sampling soft robot successfully collect the mucus reserved in the pipeline in the experiment,which effectively verified the feasibility of the intestinal soft robot designed in this paper for intestinal sampling.To sum up,two generations of intestinal sampling soft robots are proposed in this paper for the first time,which use the earthworm-like soft robot as the motion carrier and the flexible gripper and sampler as the tools respectively.This paper proposes a new potential method for the detection and treatment of intestinal diseases and promotes the application of soft robots in the medical field. |
