Caterpillar-type robots are widely used for medium- and large-sized pipe inspections. However, existing prototypes smaller than 80 mm lack both an active variable diameter capability and a contact force sensing function, which are crucial for safe and automatic exploration of unknown rigid/soft pipes (e.g., the colon). This study develops a variable diameter caterpillar-type miniature robot (VCMR) featuring a small size of Φ34.6 mm × 41 mm, a large variable-diameter range of 34.6-89.6 mm, and an integrated contact force sensing function. The VCMR actively adapts to pipe diameter changes using contact force feedback, demonstrates high load capacity in both vertical and horizontal rigid/soft pipes, and traverses a 150-cm colon phantom with sharp bends at an average velocity of 3.07 ± 0.48 cm/s. It holds promise for exploring tiny variable-diameter rigid/soft pipes and delivering cargoes through such pipes.

Constipation is a common yet distressing disease that has high rates of morbidity and impacts patients' quality of life. However, there is no perfect method to distinguish costive patients from healthy subjects. Is there chaos in human colonic activities? Are there any differences for the chaos indicators of colonic activities between healthy and costive subjects? Can these indicators distinguish patients with constipation from healthy subjects? To answer these questions, colonic pressure data from 16 healthy subjects and 48 patients with constipation were analyzed using the chaos theory. Three chaotic indicators [i.e., the largest Lyapunov exponent (LyE), correlation dimension (CorDim), and Kolmogorov entropy (KoEn)] were calculated and compared between groups with the Wilcoxon rank sum test. As a result, the LyE was greater than zero and the CorDim was fractioned, which showed that human colonic activities have clear chaotic characteristics. Statistically significant differences were observed between groups for CorDim (p < 0.05), whereas LyE did not show statistically significant differences between groups. The chaotic indicator of CorDim was able to differentiate between patients with constipation and healthy subjects. The chaos theory provides a new method for learning the nonlinear dynamics of human gastrointestinal activities.

This paper presents a set of analytical expressions used to determine the coupling coefficient between primary and secondary Litz-wire planar coils used in a transcutaneous energy transfer (TET) system. A TET system has been designed to power a novel elastic scaling artificial anal sphincter system (ES-AASS) for treating severe fecal incontinence (FI), a condition that would benefit from an optimized TET. Expressions that describe the geometrical dimension dependence of self- and mutual inductances of planar coils on a ferrite substrate are provided. The effects of ferrite substrate conductivity, relative permeability, and geometrical dimensions are also considered. To verify these expressions, mutual coupling between planar coils is computed by 3D finite element analysis (FEA), and the proposed expressions show good agreement with numerical results. Different types of planar coils are fabricated with or without ferrite substrate. Measured results for each of the cases are compared with theoretical predictions and FEA solutions. The theoretical results and FEA results are in good agreement with the experimental data.

In recent years, an intelligent noninvasive endoscope has been felt necessary for early diagnosis of malignant tumor in gastrointestine (GI). It is our purpose to develop a microwireless robotic endoscope to examine the human GI. The presented robot's diameter and length is 10 and 190 mm, respectively. A locomotion principle based on biomimetic earthworm is adopted for a higher adaptability to the GI. The robot is composed of three linear driving cells. A micromotor, a reducer, and a microscrew pair mechanism are integrated into each cell. Multijoints are used to connect every two driving cells for robot's high flexibility. The robot's energy is continuously supplied in real time by an energy transmitting system based on electromagnetic coupling. Experiments on the energy transmission and locomotion are performed to test the power transferring volume and locomotion effect in GI. The experiments indicate that the minimum received power, 400 mW, is obtained in a cylindrical space with 200 mm diameter and 200 mm length. In vitro experiments in a pig intestine indicate that this robot can move forward or backward effectively. This paper provides a good prototype for the deeper research on locomotion theory and energy transferring technology in vivo in future.

A robot system controlled by human thoughts is introduced in this paper. Aiming at the recognition problem of electroencephalogram (EEG) signals in the system, we present a novel pattern recognition method. The method combines the genetic algorithm (GA) with the support vector machine (SVM). It includes two techniques. One is that the feature selection and model parameters of the SVM are optimized synchronously, which constitutes a hybrid optimization. The other is that the hybrid optimization is realized by using the GA. The method is used to classify three types of EEG signals in the system. The experiment results show that this method can yield significantly higher classification accuracy than ones obtained with individual optimizations.