Shanghai Jiao Tong University, Shanghai, China.
Biomed Microdevices. 2020 Nov 17;22(4):82. doi: 10.1007/s10544-019-0438-1.
In order to improve the reliability, safety and whole digestive applicability of the gastrointestinal microrobot (GMR), a novel inchworm-like GMR is proposed in this paper. The expanding mechanism of the robot adopts an overlapping expanding arm structure. This structure increases the variable diameter ratio (ratio of fully expanded diameter to fully folded diameter) of the robot to 3.3, making the robot more applicable to the intestines in various parts of the human body. The mechanical model of the expanding arm is established, and the expanding force at different expanding radii is obtained. And then the expanding force is tested by a force test platform. The force test results: the maximum expanding force is 6.5 N, and the minimum expanding force is 1.3 N. The trend of the experimental and theoretical values is the same, and the experimental value is less than the theoretical value. A position limiting device based on Hall sensor is designed, which detects whether the mechanism reaches the limit position by non-contact method. This device alleviates the problem of sharp voltage drop caused by motor stall and improves the stability of the control circuit. The results of the Hall-type position limiting device (HPLD) testing show that the working currents of the expanding mechanism and the telescoping mechanism with HPLD are respectively 0.066A and 0.110A, and the robot control circuit works stably. Finally, the robot is tested in the intestine of the living pig, and the safety and reliability of the robot are verified. However, due to the decrease of the efficiency of wireless power transmission in vivo experiments and the change of the position of the receiving coil relative to the transmitting coil, sometimes the power supply is insufficient.
为了提高胃肠道微机器人（GMR）的可靠性、安全性和整体消化适用性，本文提出了一种新型的尺蠖式 GMR。机器人的扩张机构采用重叠扩张臂结构。这种结构将机器人的变径比（完全展开直径与完全折叠直径之比）提高到 3.3，使其更适用于人体各部位的肠道。建立了扩张臂的力学模型，并得到了不同扩张半径处的扩张力。然后，通过力测试平台对扩张力进行测试。力测试结果：最大扩张力为 6.5N，最小扩张力为 1.3N。实验值和理论值的趋势相同，实验值小于理论值。设计了一种基于霍尔传感器的位置限位装置，通过非接触式方法检测机构是否到达限位位置。该装置缓解了因电机失速而导致的电压急剧下降问题，提高了控制电路的稳定性。霍尔式位置限位装置（HPLD）的测试结果表明，带有 HPLD 的扩张机构和伸缩机构的工作电流分别为 0.066A 和 0.110A，机器人控制电路工作稳定。最后，在活体猪的肠道中对机器人进行了测试，验证了机器人的安全性和可靠性。然而，由于体内实验中无线功率传输效率的降低以及接收线圈相对于发射线圈位置的变化，有时会出现供电不足的情况。
