• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1205-1212
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• 2021

Robots that can actually help people a lot by dealing with dangerous tasks that are difficult for people to do, such as disaster situations, lifesaving, handling dangerous goods, and reconnaissance of dangerous areas, continue to become an issue. Therefore, in this paper, we intend to implement a mobile robot arm that can implement a human motion will on the robot arm to enable active response according to the situation and control the vehicle according to hand movements to give mobility. A controller is manufactured using a flex sensor and agyro sensor, and the roll and pitch values of the two gyro sensors are adjusted to control the angle of the robot arm and specify the vehicle direction. In addition, by designating the levels of the three flex sensors, the motor is operated according to hand movements, and a robot arm is implemented so that objects can be picked up and moved.

• Structural Engineering and Mechanics
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• v.91 no.2
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• pp.211-225
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• 2024

Soft bending actuators have gained significant interest in robotic applications due to their compliance and lightweight nature. Their compliance allows for safer and more natural interactions with humans or other objects, reducing the risk of injury or damage. However, the nonlinear behaviour of soft actuators presents challenges in accurately predicting their bending motion and force exertion. In this research, a new comprehensive study has been conducted by employing a developed 3D finite element model (FEM) to investigate the effect of geometrical and material parameters on the bending behaviour of a soft pneumatic actuator reinforced with Kevlar fibres. A series of experiments are designed to validate the FE model, and the FE model investigates the improvement of actuator performance. The material used for fabricating the actuator is RTV-2 silicone rubber. In this study, the Cauchy stress was expanded for hyperelastic models and the best model to express the stress-strain behaviour based on ASTM D412 Type C tensile test for this material has been obtained. The results show that the greatest bending angle was achieved for the semi-elliptical actuator made of RTV2 material with a pitch of 1.5 mm and second layer thickness of 1 mm. In comparison, the maximum response force was obtained for the semi-elliptical actuator made of RTV2 material with a pitch of 6 mm and a second layer thickness of 2 mm. Additionally, this research opens up new possibilities for development of safer and more efficient robotic systems that can interact seamlessly with humans and their environment.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1934-1937
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• 1999

A copper-tungsten sintered alloy(Cu-W) has been friction-welded to a tough pitch copper (Cu) in order to investigate friction weldability. The tensile strength of the friction welded joint was increased up to 87% of the Cu base metal under the condition of friction time 1.0 see, friction pressure 40MPa and upset pressure 100MPa, upset time 5.0 sec. And it is related to upset pressure rather than friction time. Mixed layer was formed in the Cu adjacent weld interface and W particles which were included in mixed layer could induce fracture in the Cu adjacent to the weld interface. Thickness of mixed layer was reduced as upset pressure increase.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.10
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• pp.1022-1028
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• 2008

This article presents an omni-tread snake robot that designed to locomote on narrow space and rough terrain. The omni-tread snake robot comprises three segment, which are linked to each other by 2 degrees of freedom joints for the pitch and yaw motion. Moving tracks on all four sides of each segment guarantee propulsion even when the robot rolls over. The 2 DOF joint are actuated by 2 servo motors which produce sufficient torque to lift the one leading or trailing segments up and overcome obstacles. This paper applies articulated steering technique to get omni-tread snake robot's kinematics model.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.98-101
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• 2000

On CELP type Vocoders G.723.1 6.3kbps/5.3kbps Dual Rate Speech Codec, which is developed for Internet Phone and videoconferencing, uses VAD(Voice Activity Detection)/CNG (Comfort Noise Generator) in order to reduce the bit rate in a silence period. In order to reduce the bit rate effectively in this paper, we first set the boundary condition of the energy threshold to prevent the consumption of unnecessary processing time, and use three decision rules to detect an active frame by energy, pitch gain and LSP distance. To evaluate the performance of the proposed algorithm we use silence-inserted speech data with 0, 5, 10, 20dB of SNR. As a result when SNR is over 5dB, the bit rate is reduced up to about 40% without speech degradation and the processing time is additionally decreased.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1049-1053
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• 2007

Cogged belts get unpleasant noise when the speed is up and down. This paper investigates optimum condition for reducing a belt noise that is caused by a belt shape and properties of the material. Order tracking is used analyze belt noise. First step, the pitch length exerts an important influence on the order noise. Second step, material of belt is also important for reducing noise level. The experimental results showed the modified form and material of belts to reduce the noise.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.2
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• pp.89-94
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• 2016

Equipments to influence by external force have to take effect mechanical oscillation. These equipments regardless of the movement on the external force such as roll, pitch and heave etc, worked to keep the height of tote are required for activeness and needed a device as equipment's fluctuation for rapidly compensation. Because the actual development of these devices is difficult to cost-effectively, we were developed to compensation simulator scaled down 1/50. In this paper, we were studying kinematic characteristics, designed the simulator to grasp the point and manufactured. This paper was analyzed for confirming the superiority of compensation simulator and set up 50 ton crane in practice.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.15-18
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• 2000

We developed a human-sized BWR(biped walking robot) driven by a new actuator based on the ball screw which has high strength and high gear ratio. The robot overcomes the limit of the driving torque of conventional BWRs. Each leg of the robot is composed of three pitch joints and one roll joint. In all, a 10 degree-of-freedom robot with two balancing joints was developed. The BWR was developed to walk autonomously such that it is actuated by small torque motors and is boarded with DC battery and controllers. In the performance test, the BWR performed nice motions of sitting-up and sitting-down. Through the test, we could find capability of high performance in biped-walking.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.569-575
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• 2000

Fabrication of carbon fiber reinforced composites was carried out by hand lay-up method. Carbon nanofibers and SiC nanofibers were used as filler in the composites fabrication. Carbon nanofibers, one of the new carbon materials, have 5∼500 nm in diameter and 5-10 nm in length. SiC nanofibers were modified by silicon monoxide vapor with carbon nanofibers. The composites were carbonized at 1000$^{\circ}C$ in a nitrogen atmosphere, and then densified by molten pitches impregnated in vacuum. Multiple cycles of liquid pitch impregnation and carbonization were carried out to obtain a desired density. The composites were characterized by density, microstructure. The inter-laminar shear strength (ILSS) test was performed for mechanical properties. For the new application, the microwave reflective proeprty of composites was investigated. Dielectric constant and permeability spectrum were measured in 12∼18 GHz frequency ranges. On the basis of the wave propagation theory in a lossy media, the reflection loss from the composite inter-layer was predict as a function of frequency.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.176.1-176
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• 2001

Conventional researches almost have been focused on the one dimensional inverted pendulum. Recently, Sprenger et al[2] have researched a two dimensional inverted pendulum Observing human's action to control an inverted pendulum, one can recognize that human uses a three dimensional metier including the up and down motion. In this paper, we propose a fuzzy logic controller(FLC) of a new three dimensional inverted pendulum system. We derive a dynamic equation of the mechanism including a 3-axis cartesian robot and a inverted pendulum. We propose a design method of a fuzzy controller of the yaw and pitch angles of a inverted pendulum. In the design, the redundant degree-of-freedom(DOF) of the robot ...