Development of flapping wing robot and vision-based obstacle avoidance strategy.

Due to the flight characteristics such as small size, low noise, and high efficiency, studies on flapping wing robots are being actively conducted. In particular, the flapping wing robot is in the spotlight in the field of search and reconnaissance. Most of the research focuses on the development of flapping wing robots rather than autonomous flight. However, because of the unique characteristics of flapping wings, it is essential to consider the development of flapping wing robots and autonomous flight simultaneously. In this article, we describe the development of the flapping wing robot and computationally efficient vision-based obstacle avoidance algorithm suitable for the lightweight robot. We developed a 27 cm and 45 g flapping wing robot named CNUX Mini that features an X-type wing and tailed configuration to attenuate oscillation caused by flapping motion. The flight experiment showed that the robot is capable of stable flight for 1.5 min and changing its direction with a small turn radius in a slow forward flight condition. For the obstacle detection algorithm, the appearance variation cue is used with the optical flow-based algorithm to cope robustly with the motion-blurred and feature-less images obtained during flight. If the obstacle is detected during straight flight, the avoidance maneuver is conducted for a certain period, depending on the state machine logic. The proposed obstacle avoidance algorithm was validated in ground tests using a testbed. The experiment shows that the CNUX Mini performs a suitable evasive maneuver with 90.2% success rate in 50 incoming obstacle situations.

Controlled growth of redox polymer network on single enzyme molecule for stable and sensitive enzyme electrode.

The electrochemical applications of enzymes are often hampered by poor enzyme stability and low electron conductivity. In this work, a novel enzyme nanogel based on atom transfer radical polymerization (ATRP) has been developed for highly sensitive detection of glucose based on ferrocene (Fc) embedded in crosslinked polymer network nanogel. Enzyme surfaces are successively modified with Br initiator, and then in situ atom transfer radical polymerization (ATRP) was performed to build up crosslinked polyacrylamide network. The resulting single enzyme nanogel (ATRP-SEG) is uniform in size fairly. ATRP-SEG reveals bi-phasic inactivation, and the half-life of stable ATRP-SEG after 18-day incubation at 50 °C is 47 days, which is 197 times longer than that of free Gox (5.7 h). By introducing a ferrocene (Fc) containing redox polymer, poly(acrylamide-co-vinylferrocene), the half-life of Fc-ATRP-SEG after 18-day incubation at 50 °C is 49 days. Fc-ATRP-SEG is used for preparation of glucose-sensing electrode, and the sensitivity of Fc-ATRP-SEG electrode is 111 µA cm-2 mM-1, which is 366 and 1270 times higher than those of free GOx (0.303 µA cm-2 mM-1) and ATRP-SEG (0.0874 µA cm-2 mM-1), respectively. Fc-ATRP-SEG electrode maintained 90% of initial current density under 4 °C storage condition and repetitive usages every day for 7 days. Even the electrode repeatedly used in continuous harsh condition (250 rpm, room temperature), the current density maintained 96% after 12 h incubation at operational condition.

Adaptive Ground Control System of Multiple-UAV Operators in a Simulated Environment.

INTRODUCTION: In the present study, an Adaptive Ground Control System for Multiple-UAV Operator Workload Decrement (AGCS) has been developed and the effectiveness of the system has been analyzed using eye-tracking and task performance data. The AGCS contained four more functions than the conventional GCS (CGCS) functions. The functions were based on real-time operator gaze information, multiple UAV operational state, and mission state information to help safe and efficient multiple UAV operation.METHODS: A total of 30 volunteers participated in the human-in-the-loop experiment to compare the performances of the newly developed AGCS and CGCS while executing reconnaissance and strike missions by operating multiple UAVs.RESULTS: According to the results, the AGCS demonstrates a statistically significant increase in mission performance, such as the mission completion rate (M = 97.3 vs. M = 95.4; SD = 3.1 vs. SD = 4.9) and mission success rate (M = 90.4 vs. M = 88.4; SD = 5.7 vs. SD = 5.6). In addition, the subjects' pupil diameter and gaze indicator show significant differences in the direction of workload reduction (α = 0.05). The subjects expressed positive opinions about using the AGCS.DISCUSSION: The originally developed AGCS showed a promising future extension based on the experimental data. After completion of the experiment, domain experts were interviewed and the next version will reflect their opinion.Lim H-J, Choi S-H, Oh J, Kim BS, Kim S, Yang JH. Adaptive ground control system of muliple-UAV operators in a simulated environment. Aerosp Med Hum Perform. 2019; 90(10):841-850.