hyungjoo kim

Dr. hyungjoo kim

orcid

Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 July 2020 in Applied Sciences
Verified
Journal Article
Open access
PDF file
HKhyungjoo kim
hyungjoo kim
JNJaeho Noh
Jaeho Noh
WYWoosung Yang
Woosung Yang
With the aging demographic of today’s society, the need for robotic exoskeletons is expected to increase as they can compensate for declining physical strength in the physically impaired. In this study, an assistive robotic exoskeleton for the knee joint with fairly low energy consumption is proposed for industrial applications. The knee-assistive robotic exoskeleton (KARE-1) was designed to support a human body during production line tasks. The KARE-1 is based on a four-bar link mechanism with a rotary actuator and gas spring to accommodate a high power-to-weight ratio. By taking advantage of the utilized singular configuration of the four-bar linkage, this novel design is able to efficiently support the weight of the human body. The selected singular configuration allows this device to support the knee joint in the load-bearing stages of static sitting as well as during the motion between standing and sitting. The proposed device is further able to move freely along with the knee during walking movements. The proposed design was verified through a series of numerical simulations and through human subject testing at an industrial workplace.

29 November 2021 in Sensors
Verified
Journal Article
Open access
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SCSooHo Choi
SooHo Choi
HKHyomin Kim
Hyomin Kim
HKhyungjoo kim
hyungjoo kim
WYWoosung Yang
Woosung Yang
The seat comfort of automobiles is one of the significant factors for determining the driver’s fatigue, emotional experience, and individual space (which captures their individuality, rather than just a means of transportation in modern society). Conventional automobile seats could not provide seating comfort suitable for all drivers, in the form of seats that fit each driver’s body type and the difficulty of meeting individual needs. This study proposes self-shape adjustable (the SSA seats) seats that improve the sitting comfort, safety, and secure the stability, by adjusting shape fit to the driver’s body type. The SSA seats transforms the seat itself, in a way that improves the distribution of contact pressure and reduces sitting fatigue, with the pneumatic system. The transformed seats provide better sitting comfort and safety than the conventional automobile seat, by providing a seat shape suitable for the body shape of all users. It was verified that the SSA seats, proposed in this paper, have a uniform and improved pressure distribution, compared to the conventional seat, in various sitting postures; the contact area between the seat and user is enlarged, and the pressure concentrated on the ischial bone is lowered. In addition, it was proven (through user evaluation) that quantitative evaluation verification was the same as qualitative evaluation results.

1 February 2013 in International Journal of Advanced Robotic Systems
Verified
Journal Article
Open access
WYWoosung Yang
Woosung Yang
HKhyungjoo kim
hyungjoo kim
BYBum Jae You
Bum Jae You
Despite recent major advances in computational power and control algorithms, the stable and robust control of a bipedal robot is still a challenging issue due to the complexity and high nonlinearity of robot dynamics. To address the issue an efficient and powerful alternative based on a biologically inspired control framework employing neural oscillators is proposed and tested. In a numerical test the virtual force controller combined with the neural oscillator of a humanoid robot generated rhythmic control signals and stable bipedal locomotion when coupled with proper impedance components. The entrainment nature inherent to neural oscillators also achieved stable and robust walking even in the presence of unexpected disturbances, in that the centre of mass (COM) was successfully kept in phase with the zero moment point (ZMP) input trajectory. The efficiency of the proposed control scheme is discussed alongside simulation results.

1 January 2014 in International Journal of Advanced Robotic Systems
Verified
Journal Article
Open access
WYWoosung Yang
Woosung Yang
JBJi-Hun Bae
Ji-Hun Bae
HKhyungjoo kim
hyungjoo kim
Since neural oscillator based control methods can generate rhythmic motion without information on system dynamics, they can be a promising alternative to traditional motion planning based control approaches. However, for field application, they still need to be robust against unexpected forces or changes in environments so as to be able to generate “natural motion” like most biological systems. In this study a biologically inspired control algorithm that combines neural oscillators and virtual force is proposed. This work gives the condition with respect to parameters tuning to stably activate the neural oscillators. This is helpful to achieve motion adaptability to environmental changes keeping the motion repeatability. He efficacy and efficiency of the proposed methods are tested in the control of a planar three-linkage robotic arm. It is shown that the proposed controller generates a given circular path stably and repeatedly, even with unexpected contact with a wall. The adaptivity of motion control is also tested in control of a robotic arm with redundant degrees of freedom. The proposed control algorithm works throughout the simulations and experiments.

28 March 2017 in SAE International Journal of Advances and Current Practices in Mobility
Verified
Conference Paper
Closed access
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SKSung Rae Kim
Sung Rae Kim
ILInju Lee
Inju Lee
HKhyungjoo kim
hyungjoo kim
This paper aims to evaluate the biofidelity of a human body FE model with abdominal obesity in terms of submarining behavior prediction, during a frontal crash event. In our previous study, a subject-specific FE model scaled from the 50th percentile Global Human Body Model Consortium (GHBMC) human model to the average physique of three female post mortem human subjects (PMHSs) with abdominal obesity was developed and tested its biofidelity under lap belt loading conditions ([1]).In this study frontal crash sled simulations of the scaled human model have been performed, and the biofidelity of the model has been evaluated. Crash conditions were given from the previous study ([2]), and included five low-speed and three high-speed sled tests with and without anti-submarining device.The biofidelity of the morphed human FE model in terms of submarining behavior was evaluated by the correlation on overall body and belt-to-pelvis kinematics between simulation and tests, and quantified by correlation and analysis (CORA) rating scores. The CORA ratings showed that the overall responses of the human FE model simulations were well-correlated with those from tests. But the belt-to-pelvis interaction that determines the submarining behavior was reasonably-correlated with that from tests since inter-subject variance in local-area responses was quite large.This study warrants further investigation on modeling parameters of pelvic bone and surrounding soft tissue to better predict the performance of anti-submarining safety device for subjects with abdominal obesity.