• Smart Structures and Systems
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• v.8 no.1
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• pp.107-117
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• 2011

Biological sensory systems continuously monitor and analyze changes in real-world environments that are relevant to an animal's specific behavioral needs and goals. Understanding the sensory mechanisms and information processing principles that biological systems utilize for efficient sensory data acquisition may provide useful guidance for the design of smart-sensing systems in engineering applications. Weakly electric fish, which use self-generated electrical energy to actively sense their environment, provide an excellent model system for studying biological principles of sensory data acquisition. The electrosensory system enables these fish to hunt and navigate at night without the use of visual cues. To achieve reliable, real-time task performance, the electrosensory system implements a number of smart sensing strategies, including efficient stimulus encoding, multi-scale virtual sensor arrays, task-dependent filtering and online subtraction of sensory expectation.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.596-601
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• 2011

Autonomous navigating algorithms for mobile robots have been proved to be a difficult task. Based on the excellent homing performance shown by many insects, bio-inspired navigation algorithms for robotic experiments have been widely researched and applied to the design of navigational strategies for mobile robots. In this paper, among them, we analyze two simple landmark navigation methods their strengths and limits. We investigate the effect of the occlusion problem mainly, which is an important yet tough problem in many landmark navigation algorithms. In the point of view of the error of homing vector and the performance of the homing paths in the environment with artificial occlusions, we investigate the effect of occlusion problem in both methods in order to further study on solutions.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1558-1562
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• 2008

Ionic polymer metal composite (IPMC), one of Electro- Active Polymer (EAP) actuators, has great attention due to the low-voltage driven, large deformation and its potential for artificial muscles. In this paper, we firstly review fish swimming modes using various propulsion mechanisms. Based on study on the swimming mechanisms, we develop an underwater robot actuator which mimics fanning motion of webfoot form. It consists of four actuators fabricated by using IPMC and PDMS which mimics Bio-inspired motion Experiments using a prototype show that the webfooted IPMC actuator generates large deformation and propulsion.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.3
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• pp.176-181
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• 2007

This paper presents evolvable neural networks based on a developmental model for navigation control of autonomous mobile robots in dynamic operating environments. Bio-inspired mechanisms have been applied to autonomous design of artificial neural networks for solving practical problems. The proposed neural network architecture is grown from an initial developmental model by a set of production rules of the L-system that are represented by the DNA coding. The L-system is based on parallel rewriting mechanism motivated by the growth models of plants. DNA coding gives an effective method of expressing general production rules. Experiments show that the evolvable neural network designed by the production rules of the L-system develops into a controller for mobile robot navigation to avoid collisions with the obstacles.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.912-916
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• 2018

Crawling robots are advantageous in overcoming obstacles. These robots have characteristics such as light weight and outstanding mobility. In case of large robots, they have difficulties passing narrow gaps or entering the cave. In this paper, we propose a milli-scale hexapedal robot using 4-bar linkages. Two conditions are necessary to enable efficient walking. In short, the trajectory of the foot must be elliptical, and the lowest point of the foot should be the same. These conditions are satisfied with a novel leg design. The robot has a pair of three legs and the legs are coupled to operate simultaneously. Each set of the legs are installed to robot's both sides and the legs satisfy the equal lowest foot point and elliptical trajectory. As a result, this hexapedal robot can crawl with 0.56m/s speed.

• Smart Structures and Systems
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• v.8 no.1
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• pp.53-67
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• 2011

Human state in human-machine systems highly affects the overall system performance, and should be detected and monitored. Physiological cues are essential indicators of human state and useful for the purpose of monitoring. The study presented in this paper was focused on developing a bio-inspired sensing system, i.e., Nano-Skin, to non-intrusively measure physiological cues on human-machine contact surfaces to detect human state. The paper is presented in three parts. The first part is to analyze the relationship between human state and physiological cues, and to introduce the conceptual design of Nano-Skin. Generally, heart rate, skin conductance, skin temperature, operating force, blood alcohol concentration, sweat rate, and electromyography are closely related with human state. They can be measured through human-machine contact surfaces using Nano-Skin. The second part is to discuss the technologies for skin temperature measurement. The third part is to introduce the design and manufacture of the Nano-Skin for skin temperature measurement. Experiments were performed to verify the performance of the Nano-Skin in temperature measurement. Overall, the study concludes that Nano-Skin is a promising product for measuring physiological cues on human-machine contact surfaces to detect human state.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.410-413
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• 2012

A traditional fabrication method is very difficult to make small robots using embedded sensors, actuators and connectors. Fortunately, Shape Deposition Manufacturing can provide an alternative method, and it has many benefits. Firstly, the weight of robot can be lighter, as it can be consisted of composite materials. Secondly, SDM can make simple robot structures because this approach does not need to use connectors and fasteners. Lastly, SDM gives stiffness and flexibility at the specific parts. Therefore, in this paper, we present a design of 3 segment legs organized by SDM, what the SDM approach is, and compare SDM method with 3 segment prototype legs which uses a traditional approach and made by DGIST.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1023-1029
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• 2013

Water running animals such as basilisk lizards have an advantage of high-speed movement and high power efficiency on water; so researchers in robotic fields have been interested in the water running locomotion. This paper presents prototype-design and experimental study on the fourand six-legged water running robot. Based on the previously proposed quadruped water running robot, we assemble a hexapedal water running robot. The legs of the water running robot are designed based on four-bar parallel link for repeated motion along to pre-defined path. Stability performance of the quadruped and hexapedal water running robot are investigated by experiments on rolling criterion. As a result, hexapedal robot performs better stability than quadruped robot. Based on the hexapedal robot design, we are planning to optimize the position of legs and operating frequency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.844-849
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• 2008

We present a novel cell deformability monitoring chip based on the digitally measured cell lysis rate which is dependent on the areal strain of the cell membrane. This method offers simple cell deformability monitoring by automated high-throughput testing system. We suggest the filter design considering the areal strain imposed on the cell membrane passing through the filter array having gradually increased orifice length. In the experiment using erythrocytes, we characterized the cell deformability in terms of average fracture areal strain which was $0.24{\pm}0.014\;and\;0.21{\pm}0.002$ for normal and chemically treated erythrocytes, respectively. We also verified that the areal strain of 0.15 effectively discriminates the deformability difference of normal and chemically treated erythrocytes, which can be applied to the clinical situation. We compared the lysis rates and their difference for the samples from different donors and found that the present chips can be commonly used without any calibration process. The experimental results demonstrate the simple structure and high performance of the present cell deformability monitoring chips, applicable to simple and cost-effective cell aging process monitoring.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.9
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• pp.712-722
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• 2018

This paper conducts parametric studies on flapping wing design, one of the most important design parameters of insect-mimicking aerial vehicles. Experimental study on wing shape was done through comparison and analysis of thrust, pitching moment, power consumption, and thrust-to-power ratio. A two-axis balance and hall sensor measure force and moment, and flapping frequency, respectively. Wing configuration is biplane configuration which can develop clap and fling effect. A reference wing shape is a simplified dragonfly's wing and studies on aspect ratio and wing area were implemented. As a result, thrust, pitching moment, and power consumption tend to increase as aspect ratio and area increase. Also, it is found that the flapping mechanism was not normally operated when the main wing has an aspect ratio or area more than each certain value. Finally, the wing shape is determined by comparing thrust-to-power ratio of all wings satisfying the required minimum thrust. However, the stability is not secured due to moment generated by disaccord between thrust line and center of gravity. To cope with this, aerodynamic dampers are used at the top and bottom of the fuselage; then, indoor flight test was attempted for indirect performance verification of the parametric study of the main wing.