A Preliminary Study On The Locomotion Control Of The Intestinal Bio-robot System

In clinical environment, the intestinal diseases are very common. The special structure of intestinal position makes the diagnosis and treatment of intestinal diseases very difficult. Therefore, the scientists and researchers always focused on the diagnosis and treatment of intestinal diseases. Currently, the intestinal treatment devices at home and abroad are the traditional intestinal endoscopy, the intestinal medical capsule and the intestinal robot. The three types of intestinal treatment devices play an important role on the detection and diagnosis of intestinal diseases. However, there are some shortcomings existing in the devices metioned above. The traditional intestinal endoscopy is invasive, and difficult to reach the lower part of the small intestine. The intestinal medical capsule is drived passively and the movement and posture are mainly controlled by the intestine wiggle. The active intestinal medical capsule and intestinal robot are still has many shortcomings in their drive modes.This paper presents a bio-robot system which is controlled by micro neural electrodes. It combines by two parts. One part is for diagnosis and treatment which enters the intestine. Another part in vitro is for control. The present system combines the organism, neural control and electrical system. It uses the organism as the driver of first part to carry the intestinal clinic devices into the intestine. Then the second part controls the electrical stimulation of the organism nerve, so as to make a remote control of the movement of the organism. These features enable the first part to go deep into the intestine, diagnose the intestine and targeted deliver drug. Bio-robot has some advantages such as supplying energy, flexible movement and so on.It is worthy to study the bio-robot system to address the driver problem of intestinal active treatment device. If the problem of active drive can be solved, it will greatly promote the development of gastrointestinal minimally invasive diagnostic and therapeutic technique.Firstly, based on the features of Mud eel metioned, the organism of a Mud eel was selected in the present work which has the following advandages. It can move in the narrow channel because of the smooth surface and it can survive in a confined environment and its nervous system of motion can be controlled thoroughly. According to its mechanism of motion control, the non-conditioning control method was used. The rear lateral line was selected as stimulation sites which lie in both sides of the body after the head.Secondly, the stimulate control system was designed. Our work designed and production the surface neuronal microelectrodes and the implantable micro-nerve needle electrodes based on the body length (380 mm±20 mm) and trunk circumference (38mm±3mm) of the Mud eel. The positive phase voltage stimulator, the positive phase current stimulator, the bipolar voltage stimulator, the biphasic current stimulator were designed for the in vitro stimulation experiments. The voltage, frequency, duty cycle in different parts of the Mud eel were measured using the stimulate system which is composed of the surface type and the implantable electrodes with the positive phase voltage stimulator after measuring the impedance of the Mud eel. The stimulating effect was measured using the stimulate system which is composed by the surface type and the implantable electrodes with the bipolar voltage stimulator, the biphasic current stimulator. The best experimental model for motion control stimulation in vitro preliminary experiments was select.Finally, the motion control stimulation in vitro preliminary experiments was carried out. We explored the way to control Mud eel move forward in the plastic film tube by the experiments of one point stimulate and a number of points stimulate on 12 Mud eel. Then experiment on 24 Mud eel in the simulated intestine was conducted and the speed of advance was determined based on the same method. We also performed the experiment on 6 Mud eel in the fresh pig intestine using the method above.The results show that the best performance can be achieved when the stimulation electrodes is implanted in the middle of the tail and the bipolar current pulse is used with a amplitude of 1.5uA, frequency of 2Hz and width of 750uS. The rate of controlling moving forward of the Mud eel is 99.90%.This paper confirms the controllability of Mud eel movement and provides the necessary basis for the future development of the intestinal bio-robot system. As our study of intestinal bio-robot system is still in the initial stage,there are many works needeed to be explored.