• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.80-80
• /
• 2000

The GPS can provide accurate position information on the earth. But GPS receiver can't give position information inside buildings. DR(Dead-Reckoning) or INS(Inertial Navigation System) gives position information continuously indoors as well as outdoors, because they do not depend on the external navigation information. But in general, the inertial sensors severely suffer from their drift errors, the error of these navigation system increases with time. GPS and DR sensors can be integrated together with Kalman filter to overcome these problems. In this paper, we developed a personal navigation system which can be carried by person, using GPS and electronic pedometer. The person's footstep is detected by an accelerometer installed in vertical direction and the direction of movement is sensed by gyroscope and magnetic compass. In this case the step size is varying with person and changing with circumstance, so determining step size is the problem. In order to calculate the step size of detected footstep, the neural network method is used. The teaming pattern of the neural network is determined by human walking pattern data provided by 3-axis accelerometer and gyroscope. We can calculate person's location with displacement and heading from this information. And this neural network method that calculates step size gives more improved position information better than fixed step size.

• Korean Journal of Applied Biomechanics
• /
• v.24 no.3
• /
• pp.259-267
• /
• 2014

The purpose of this study was to find the relationship between standing posture biomechanics and physical fitness in the elderly. Physical fitness variables and postural variables for 227 (140 women and 87 men) elderly individuals were tested. Physical fitness tests (Korean Institute of Sports Science, 2012) included 3m sit, walk, and return, grip test, 30 second chair sit and stand, sit and reach, figure 8 walks, and 2 minute stationary march. Postural biomechanics variables included resting calcaneal stance position (RCSP), shoulder slope, pelvic slope, knee flexion angle, leg length difference, thoracic angle, and upper body slope. In statistical analysis, multiple regression was conducted by using stepwise selection method via SAS (version 9.2). Analysis for both men and women revealed significant relationships between physical fitness and age, upper body slope, knee flexion angle, leg length difference. Pelvic and thoracic angle were only related to figure 8 walking and sit and reach in women, while RCSP and shoulder slope had no relationship with any physical fitness variables.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.7 s.172
• /
• pp.112-121
• /
• 2005

This paper is concerned with smooth trajectory generation of biped robot which has inverted pendulum type balancing weight. Genetic algorithm is used to generate the trajectory of the leg and balancing weight. Balancing trajectory can be determined by solving the second order differential equation under the condition that the reference ZMP (Zero moment point) is settled. Reference ZMP effect on gait pattern absolutely but the problem is how to determine the reference ZMP. Genetic algorithm can find optimal solution under the high order nonlinear situation. Optimal trajectory is generated when use genetic algorithm which has some genes and a fitness function. In this paper, minimization of balancing joints motion is used for the fitness function and set the weight factor of the two balancing joints at the fitness function. Inverted pendulum type balancing weight is very similar with human and this model can be used fur humanoid robot. Simulation results show ZMP trajectory and the walking experiment made on the real biped robot IWR-IV.

• Korean Journal of Applied Biomechanics
• /
• v.23 no.1
• /
• pp.63-76
• /
• 2013

The purpose of this study was to investigate the effects of knee joint muscle fatigue and overweight on the angular displacement and moments of the lower limb joints during landing. Written informed consent forms, which were approved by the human subject research and review committee at Dong-A University, were provided to all subjects. The subjects who participated in this study were divided into 2 groups: a normal weight group and an overweight group, consisting of 15 young women each. The knee joint muscle fatigue during landing was found to increase the dynamic stability by minimizing the movements of the coronal and horizontal planes and maintaining a more neutral position to protect the knee. The effect of body weight during landing was better in the normal weight group than in the overweight group, with the lower limbs performing their shock-absorbing function in an efficient manner through increased sagittal movement. Therefore, accumulated fatigue of knee joint muscles or overweight may be highly correlated with the increase in the incidence of injury during landing after jumping, descending stairs, and downhill walking.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.11
• /
• pp.954-962
• /
• 2002

In a park or street, we can see many people jogging or walking with their dogs tracking their masters. In this study, an entertainment robot that imitates a dog's behavior is created. The robot's task is tracking a moving target that is recognized as the master. In order to design the robot, the ecological approach. in which the robot's goals and surroundings heavily influence its design, is used. A three-wheel type locomotion system is designed as the robot's physical structure which can follow a human jogging in outdoor space like a park. A sensor system which can detect the position of a master for the robot in the outdoor space, is developed. This sensor system consists of a signal transmitter which is at the hand of a master and some sensors which are mounted on the robot. The transmitter emits RF(radio frequency) and ultrasonic signals and the sensors detect the direction and distance from the robot to the transmitter by using the received signals. For the control architecture of the robot, a purely reactive behavior-based method is used in order to increase speed of response. The developed robot is evaluated through experiments conducted in indoor and outdoor environments.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.7
• /
• pp.615-620
• /
• 2015

DOB (Disturbance Observer) is an useful control method for estimating the disturbance applied to dynamic systems. Disturbance observer can be used to implement a robust control system to generate a control input for rejecting the disturbance, and it can be also used to estimate the disturbance to obtain information. The system that uses disturbance estimation is investigated for high performance control such as automatic door systems, walking robot and electric power steering system in vehicles. In this paper, a novel disturbance observer which is called disturbance and current observer for estimating load torque in the motor system is proposed. The difference between the DOB for disturbance rejection and DCOB is mathematically verified. Current and angular velocity are required for estimating the load torque of the motor in DOB. However, the DCOB can estimate load torque and current without current sensor. DCOB is designed based on modeling of the motor system. Appropriate Q-filter is selected and the applicability of DCOB is verified by simulation. The estimated disturbance and current of the electric motor can be verified without current sensor, as experiments of the actual motor system.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.8
• /
• pp.135-143
• /
• 2003

This paper presents the impact minimization of a biped robot by using genetic algorithm. In case we want to accomplish the designed plan under the special environments, a robot will be required to have walking capability and patterns with legs, which are in a similar manner as the gaits of insects, dogs and human beings. In order to walk more effectively, studies of mobile robot movement are needed. To generate optimal motion for a biped robot, we employ genetic algorithm. Genetic algorithm is searching for technology that can look for solution from the whole district, and it is possible to search optimal solution from a fitness function that needs not to solve differential equation. In this paper, we generate trajectories of gait and trunk motion by using genetic algorithm. Using genetic algorithm not only on gait trajectory but also on trunk motion trajectory, we can obtain the smoothly stable motion of robot that has the least impact during the walk. All of the suggested motions of biped robot are investigated by simulations and verified through the real implementation.

• Journal of Korean Society of Rural Planning
• /
• v.26 no.3
• /
• pp.13-24
• /
• 2020

As the importance of rural landscapes has recently emerged due to an increase in number of urban to rural migrants into suburban area in Korea, this study empirically grasps the differences in subjective landscapes perceptions between native and non-native residents. and tried to explore new landscape management possibilities through the role of each residents group. To this end, based on the data collected through the 'photo-elicitation with walking', the residents' landscape perception objects, perception factors, and perceived feelings are derived, and then the differences and characteristics of landscapes perception between native and non-native residents group were analyzed. As a result, native residents perceived everyday landscapes relatively meaningfully and provided abundant information in all aspects, while non-native residents mainly recognized characteristic landscapes and responded more sensitively to visual and environmental perception factors than the natives. Non-native residents also showed strong willingness to improve the degraded landscapes. These results are expected to provide a basis for exploring the role of residents in rural landscape planning and management in the future.

• Journal of Information Processing Systems
• /
• v.10 no.2
• /
• pp.176-192
• /
• 2014

The realization of Wireless Multimedia Sensor Networks (WMSNs) has been fostered by the availability of low cost and low power CMOS devices. However, the transmission of bulk video data requires adequate bandwidth, which cannot be promised by single path communication on an intrinsically low resourced sensor network. Moreover, the distortion or artifacts in the video data and the adherence to delay threshold adds to the challenge. In this paper, we propose a two stage Quality of Service (QoS) guaranteeing scheme called Prioritized Multipath WMSN (PMW) for transmitting H.264 encoded video. Multipath selection based on QoS metrics is done in the first stage, while the second stage further prioritizes the paths for sending H.264 encoded video frames on the best available path. PMW uses two composite metrics that are comprised of hop-count, path energy, BER, and end-to-end delay. A color-coded assisted network maintenance and failure recovery scheme has also been proposed using (a) smart greedy mode, (b) walking back mode, and (c) path switchover. Moreover, feedback controlled adaptive video encoding can smartly tune the encoding parameters based on the perceived video quality. Computer simulation using OPNET validates that the proposed scheme significantly outperforms the conventional approaches on human eye perception and delay.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.18 no.7
• /
• pp.48-55
• /
• 2019

Soldiers have been exposed to the risk of chilblains in cold winters. Recent studies have described sensors and IOT devices that use independent power sources based on piezoelectric energy harvesting. Therefore, the heated shoes with an independent power source have been developed. For the application of energy harvesting to shoes, it is necessary to develop a unique harvester by considering human gait characteristics. Energy harvesters and ceramics were designed and fabricated in this study. The performances of these harvesters and ceramics were evaluated experimentally. Then, the harvesters and ceramics with superior performance were selected and applied to the system. Thereafter, the heating and charging performance of the system was tested under real walking conditions. The results show that the developed system can generate adequate energy to charge the battery and heat the shoes.