• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.3
• /
• pp.183-190
• /
• 2016

In this study, we conduct linear and nonlinear modeling of the DC motor driving system of a wheeled mobile robot, which is a nonlinear system involving dead zone, friction, and saturation. The DC motor driving system consists of a DC motor, a wheel, and gears. A linear DC motor driving system is modeled using a steady-state response and parameter measurements. A nonlinear DC motor driving model is identified with the use of the Hammerstein-Wiener method. By using these models, PID controllers for the DC motor system are then established. Each PID controller is applied as a low-level controller in order to achieve posture stabilization control for the real mobile robot. We also compare the performance of the proposed PID controllers in posture stabilization experiments by using several different final robot postures.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.10 no.6
• /
• pp.587-593
• /
• 2017

In this paper, we propose a method to solve the difficulties in constructing an environment capable of practical training on the theoretical contents of robot control field. We make a two-wheeled mobile robot with Segway structure using LEGO block. In order to demonstrate the validity of using the developed robot as a practical application of advanced control theory of robotics education such as dynamic system and nonlinear system, the robot takes a stable posture while balancing the change of gravity during running. The results of the experiment are shown. By presenting the results, the robots made using the LEGO block are used for practical training of advanced control theory of robotics. It can be used as a tool.

• Physical Therapy Rehabilitation Science
• /
• v.11 no.4
• /
• pp.436-445
• /
• 2022

Objective: Deformation of soft tissues around the neck and scapularcan caused by forward head posture(FHP), which has an uncomfortable effect on biomechanical changes in the scapula as well as functional disorders of the shoulder. However, studies related to direct FHP, biomechanical changes in the scapulafunction, and shoulder pain and disorder have not yet been conducted. Therefore, purpose of this study is to effect of decresedthe FHP on the shoulder function of the sacpular biomechanical examine the change in the shoulder painand disorder. Design: A randomized controlled trial Methods: The participants were 32adults(23.03±3.90 years) recruited and redivided randomly into Forward head posture corrective exercise(FHPCE) vs Control. The FHPCE group was proceeded according to the over load principle through 2steps biofeedback exercise and corrective exercise(n=16). The control (n=16) was TENS did not operated and padding 20 minute. This study was conducted 3 times a week for 4a weeks. Results: FHPCE group is improve in the results of craneocervical angle(p<0.05, 95% CI: 0.352, 4.073). In Mechanical changes of scapula in the shoulder flexion more significant improvement in FHPCE than control group[Axis X(p<0.05), Y(p<0.01), Z(p<0.01)], and shoulder abductionmore significant improvement in FHPCE than control group[xis X(p<0.01)], as well FHPCE showed significant increased in the results in the shoulder pain(p<0.05, 95% CI: -13.244, -1.566) Conclusions: This study suggected that FHP affects the biomechanical changes of the shoulder, and a new method for shoulder pain intervention

• 대한약리학회:학술대회논문집
• /
• 2006.10a
• /
• pp.123.1-123.1
• /
• 2006

• Transactions on Control, Automation and Systems Engineering
• /
• v.4 no.1
• /
• pp.43-48
• /
• 2002

We show that humans execute the postural control ingeniously by regulating the impedance properties of the musculo-skeletal system as the motor command against the alteration of the environment. Adjusting muscle activity can control the impedance properties of the musculo-skeletal system. To quantify the changes in human arm viscoelasticity on the vertical plane during interaction with the environment, we asked our subject to hold an object. By utilizing surface electromyographic(EMG) studies, we determined a relationship between the perturbation and a time-varying muscle co-activation. Our study showed when the subject lifts the object by himself the muscle stiffness increases while the torque remains the same just before the lift-off. These results suggest that the central nervous system(CNS) simultaneously controls not only the equilibrium point(EP) and the torque, but also the muscle stiffness as themotor command in posture control during the contact task.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.5 s.176
• /
• pp.1155-1165
• /
• 2000

Due to the irregularity of walking ground and the inaccuracy in trajectory control of a leg, the mechanical shock and slip on the ground can be caused in the landing and supporting legs of a walkin g robot, and the robot may lose walking stability. Especially in a jointed-leg type walking robot, those problems are much more severe than in the pantograph type since the leg-weight of the jointed-leg type walking robot is relatively heavier than that of the pantograph type in general. In order to secure the walking stability for the jointed-leg type quadrupedal robot under development in KIST(Korea Institute of Science and Technology), a balancing algorithm consisting of the leg compliance control and the body posture control is implemented in this paper, and the effectiveness of the algorithm is verified through experiments.

• The Journal of Korean Physical Therapy
• /
• v.25 no.2
• /
• pp.103-109
• /
• 2013

Purpose: This study was conducted in order to suggest an effective method of daily life movement training for stroke patients by comparison and analysis of the biomechanic characteristics of sitting up from a lying posture in stroke patients and healthy elderly participants. Methods: Fifteen stroke patients and 15 age-matched elderly participants were included in the study. The movement of sitting up from a lying posture was divided into three stages, and the differences in muscle activity in the sternocleidomastoid (SCM), rectus abdominis (RA), external oblique (EO), and rectus femoris (RF) during the movement were analyzed. Results: Subjects in the experimental group showed slower speed than those in the control group. In the neck joint, the change of angle in movement showed a larger decrease at all stages in the experimental group than in the control group; the movement also decreased in stages I and II in the upper trunk joint. The movement also showed a statistically significant decrease in stage II in the lower trunk, pelvic, and hip joints. The SCM showed higher activity in the control group than in the experimental group, showing a statistically significant difference; the RA showed high activity in the experimental group. The RF showed higher activity in the control group than in the experimental group, showing a statistically significant difference. Conclusion: From the results obtained above, increasing movements in the neck, pelvic, and hip joints and strengthening of lower body muscles are required in order to improve the ability for getting up from a lying posture in stroke patients.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.46 no.6
• /
• pp.36-42
• /
• 2009

In the mobile device environment, the context-aware computing has been emerging as a core technology of ubiquitous computing. Compared with a desktop computer, a user interface and resource of mobile device is very limited. Traditional desktop-based user interface has been developed on the basis that a user's activity is static state. In contrast, mobile devices are not able to utilize representative desktop-based interaction mechanisms such as a keyboard and mouse, not only because the activity of a user is dynamic state, but mobile devices have limited resources and small LCD display. In this paper, we introduce an intelligent control system for the mobile device that can utility effectively the limited resource and complement the poor user interface by using an accelerometer being able to sense the physical activity and posture. The proposed system can estimate the user activity, static and dynamic states, and posture watching the PDA at the same time, and the proposed intelligent control system as its application, the backlight ON/OFF on the PDA, is run by the result of the user's behavior.

• Korean Journal of Applied Biomechanics
• /
• v.23 no.3
• /
• pp.261-269
• /
• 2013

The purpose of this study was to investigate the degree of improvement of scoliosis, muscle function and VAS between the exercise group and the control group after conducting correct posture exercise program with 20 female students diagnosed with scoliosis through PAPS in M middle school for 12 weeks. The conclusion was as follows. Cobb's angle in exercise group was changed from $11.6^{\circ}{\ae}2.5^{\circ}\acute{y} $ to $7.3^{\circ}{\ae}2.0^{\circ}\acute{y} $ which was statistically significant difference (p<.001). However, the change in Cobb's angle was not significant in control group, hence there was no statistically significant difference. The limber back strength was changed from $45.9^{\circ}{\ae}8.7$ kg to $51.6^{\circ}{\ae}14.9$ kg and sit-up was changed from $13.7^{\circ}{\ae}5.1$ times to $12.9^{\circ}{\ae}5.3$ times in exercise group, but they were not statistically significant. Control group also showed no statistically significant change in back strength and sit-up. The degree of VAS was changed from $7.3^{\circ}{\ae}1.6$ to $3.3^{\circ}{\ae}2.4$ which was a statistically significant difference (p<.01) in exercise group. However, there was no statistically significant difference in control group. Consequently, correct posture exercise program was considered to be effective for the reduction of Cobb's angle and degree of VAS for middle school female students with scoliosis. Therefore the correct posture exercise program can be recommended for youth scoliosis to improve and prevent the body imbalance and ultimately for the health of the youths.

• The Journal of Korean Physical Therapy
• /
• v.33 no.1
• /
• pp.1-6
• /
• 2021

Purpose: This study examined the effects of heel insoles on the static balance and leg muscle activity and posture control strategy during external perturbation. Methods: Thirty healthy young men participated in the study. The subjects underwent two experimental conditions: 1) no heel insole condition (0cm) and 2) wearing heel insole condition (5cm). The static balance was measured using an I-Balance device, which measured the change in the center of gravity (COG). The onset time of muscle activation and muscle activation of the erector spinae (ES), hamstring (HAM), gastrocnemius (GCM) were measured using surface EMG electrodes to determine the change in posture control strategy during external perturbation. Results: The speed and distance of COG were significantly higher in the wearing heel insoles condition than the no heel insole condition (p<0.05). In addition, significant differences in the onset time of the GCM, HAM, and ES muscle activation were observed when there was no heel insole condition during external perturbation (p<0.017). On the other hand, no significant differences in the onset time of muscle activation were observed between GCM and HAM when wearing the heel insole condition during external perturbation (p<0.017). Moreover, muscle activation of the GCM was significantly higher in the wearing heel insoles condition than the no heel insole condition during external perturbation (p<0.05). Conclusion: These findings suggest that heel insoles may have disadvantages, and increased efforts are needed to maintain balance and change the posture control strategy during external perturbation.