• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.12
• /
• pp.1284-1289
• /
• 2014

In this Paper, outdoor position estimation system was implemented using GPS (Global Positioning System) and INS (Inertial Navigation System). GPS position information has lots of errors by interference from obstacles and weather, the surrounding environment. To reduce these errors, multiple GPS system is used. Also, the Discrete Wavelet Transforms was applied to INS data for compensation of its error. In this paper, position estimation of the mobile robot in the straight line is conducted by EKF (Extended Kalman Filter). However, curve running position estimation is less accurate than straight line due to phase change in rotation. The curve is recognized through the rate of change in heading angle and the position estimation precision of the initial curve was improved by UPF (Unscented Particle Filter). In the case of UPF, if the number of particle is so many that big memory gets size is needed and processing speed becomes late. So, it only used the position estimation in the initial curve. Thereafter, the position of mobile robot in curve is estimated through switching from UPF to EKF again. Through the experiments, we verify the superiority of the system and make a conclusion.

• Journal of Oral Medicine and Pain
• /
• v.20 no.1
• /
• pp.195-204
• /
• 1995

The purpose of this study was to evaluate effect of head posture change on initial occlusal contacts through measuring the distances between initial occlusal contacts and maximum intercuspal position at different head posture. Two special devices were designed and constructed. Mandibular movement replicator was used to assess reliability of the K6 diagnostic system(MKG; Myo-tronic Inc, Seatle, USA) and head posture calibrator was used to maintain the constant head posture during experiment. We measured difference of distance between initial occlusal contact and maximum intercuspal position with MKG in upright, supine, 45 degrees extension, 30 degrees flexion, 30 degrees right and left bending postion of the head. The Frankfurt horizontal plane was used as a reference plane. 21 adults aged from 23 to 25 were selected, who have normal or class I molar relationship, and have no symptoms on TMJ and masticatory muscles, and have restorations less than 3 surfaces on each tooth, and have no other prosthetic restoration. The obtained results were as follows : The mean absolute distances between initial occlusal contact and maximum intercuspal postion were 0.39(0.18mm in the upright position, 0.65(0.37mm in the supine position, 0.59(0.33mm in the 45 degree extension, 0.70(0.53mm in the 30 degrees flexion, 1.12(1.10mm in the 30 degrees right bending and 1.94(0.67mm in the 30 degrees left bending of the head. The positions of the initial occlusal contacts have a tendency to locate anterior, left and inferior to maximal intercuspal position in upright position, posterior and inferior in supine position and 45 degrees extension, anterior and inferior in 30 degrees flexion, right and inferior in 30 degrees right bending, and left and inferior in 30 degrees left bending of the head. There were significant differences among the initial occlusal contacts in each head postures(P<0.0001). Therefore, we need to check initial occlusal contacts in the altered head posture during occlusal analysis and adjustment of occlusal appliance and dental occlusion for diagnosis and treatment of temporomandibular disorder.

• The korean journal of orthodontics
• /
• v.26 no.1 s.54
• /
• pp.43-52
• /
• 1996

The purpose of this study was to compare and evaluate the upper airway structure between the snorers and asymptomatic control subjects depending on the positional change. Lateral cephalograms in the upright and supine position were taken in 25 female snorers and 20 female asymptomatic control subjects. The length and the area of the soft palate, tongue and airway were measured and evaluated statistically. The results obtained were as follows : 1. The snorers showed longer and higher tongue, narrower and longer airway, inferiorly positioned hyoid bone, longer and broader soft palate and narrower hypopharynx than the control subjects both in the upright and supine position. In addition, the snorers showed broader tongue area and narrower oropharynx area than the control subjects in supine position. 2. Depending on the positional change from upright to supine position, the controls and the snorers showed decreased airway length and superior positioned the hyoid bone. In addition, the snorers showed decreased tongue length and height, airway length and thickness and oropharynx area, but increased tongue area and soft palate area.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.24 no.2
• /
• pp.51-58
• /
• 2018

Backdround: Using RUSI (Rehabilitation Ultra Sound Imiging) method, which showed high reliability in soft tissue measurements, we compared the muscle relax and contraction, sex, and physical characteristics of the activity of the multifidus muscle in patients with chronic low back pain and normal subjects. Methods: In this study, 16 patients (male: 8, female: 8) with chronic low back pain and 16 healthy adult (male: 8, female: 8) were participated. Subjects lied prone posture on the table with elbow flexed $90^{\circ}$ and shoulder abducted $120^{\circ}$ (starting position). Test was applied two types that muscle relax position and muscle contraction position. Muscle relax position is equal to starting position and muscle contraction position is that upper extremity lift up about 5cm from the table. We measured the thickness of the multifidus muscle in each position by ultrasound. Results: There was a statistically significant difference between the two groups in deviation of Both Side Difference of Activated resting-Arm Lifting Ratio according to posture change between the chronic low back pain patient group and the normal group. Conclusion: The result of this study support previous study showing that there is an imbalance in the activity of multifidus in patients with chronic low back pain.

• Journal of the Ergonomics Society of Korea
• /
• v.30 no.6
• /
• pp.757-764
• /
• 2011

Objective: The aim of this study was to provide a method to improve the compliance and reduce the time by reducing the workload during the model change work. Background: The enterprises are constructing the small quantity batch production system by increasing the number of model change and reducing model-changing. However, the compliance is low because the work is strenuous and high skills are needed, so the system management is facing with many difficulties. Method: After classifying the model change work according to the purposes(preparation, change and adjustment) with the target of mascara filling machine, element tasks time were measured and the motion analysis(therblig symbol) and REBA analysis were performed. The study incorporated 3 independent variables as the number of motion, REBA score and the element time. The dependent variable is the type of element work as preparation, change and adjustment. The statistical test was performed by one-way ANOVA(${\alpha}$ < 0.05). Results: For the preparation, the number of motions appeared in the order of Use(U), Transport Loaded(TL), and Position(P). The order appeared in change is Use(U), Release Load(RL), and Grasp (G). The adjustment appeared in the order of Position(P) and Use(U). The results of average motion time as the element work times divided by the number of motion appeared in the order of adjustment(1.85sec/motion), preparation(1.11sec/motion), and change(0.62sec/motion). The results of REBA showed that the average risk level of change and adjustment were medium, but 53.1% of change and 42.9% of adjustment were evaluated as high. Conclusion: Reducing the avoidance and improving the compliance of work could be expected if the job autonomy were improved by improving the working postures with high risk level. Application: It is expected to solve the problem of reducing the time of model change work in the small quantity batch production system. The future work is to carry out the improvement directions found in the results and compare the results after improvement.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10a
• /
• pp.1042-1046
• /
• 1993

This paper describes a control scheme for a robot manipulator system which uses visual information to position and orientate the end-effector. In this scheme, the position and orientation of the target workpiece with respect to the base frame of the robot are assumed to be unknown, but the desired relative position and orientation of the end-effector to the target workpiece are given in advance. The control scheme directly integrates visual data into the servoing process without subdividing the process into determination of the position and orientation of the workpiece and inverse kinematics calculation. A neural network system is used for determining the change in joint angles required in order to achieve the desired position and orientation. The proposed system can be control the robot so that it approach the desired position and orientation from arbitrary initial ones. Simulation for the robot manipulator with six degrees of freedom will be done. The validity and the effectiveness of the proposed control scheme will be verified by computer simulations.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.31-36
• /
• 1999

In this paper, a novel indirect rotor position sensing method is proposed to improve the performance of sensorless drive of brushless DC motors. Fast mode change to the sensorless operation is difficult in the existing indirect rotor position sensing methods because precise rotor position can not be obtained when an excessive input is applied to the drive during synchronous operation mode. To cope with this problem, the relationship between terminal voltage and back-emf waveform is analyzed in this paper, also a novel indirect position sensing method which can detect a precise rotor position at low speed range is proposed. The effectiveness of the proposed method is verified through the experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.5
• /
• pp.40-47
• /
• 2012

The PMSM position sensor using two rectangular hall sensors can restrictively acquire the 90[$^{\circ}$] position information of rotor according to electrical angle. Thus, the control method using this position sensor cannot react properly to a rapid load torque change. On the other hand, even though a sensorless method has the advantage of acquiring instantaneous rotor position information, the accuracy of position sensor can be determined by the gain value of estimator. This paper suggests a robust speed control method on torque fluctuation condition, which combines low cost two rectangular hall sensors and sensorless control method.

• Journal of Power Electronics
• /
• v.5 no.1
• /
• pp.62-66
• /
• 2005

A simple fault correction method for rotor position detection of a brushless DC(BLDC) motor with trapezoidal back EMF(electromotive force) using a Hall effect latch unit is presented. The reason why the Hall effect latch unit does not operate properly during the startup of a BLDC motor is thoroughly explained. To solve this problem, a simple code change method and its hardware implementation issues are proposed and discussed.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.1
• /
• pp.97-103
• /
• 2013

This paper describes the characteristics of Electronic Throttle Controller (ETC) module in BLDC motor without the hall sensor for detecting a rotor position. The proposed ETC control system, which is mainly consisted of a BLDC motor, a throttle plate, a return spring and reduction gear, has a position sensor with an analogue voltage output on the throttle valve instead of BLDC motor for detecting the rotor position. So the additional commutation information is necessarily needed to control the ETC module. For this, the estimation method is applied. In order to improve and obtain the high resolution for the position control, it is generally needed to change the gear ratio of the module or the electrical switching method etc. In this paper, the 3-phase switching between successive commutations is adapted instead of the 2-phase switching that is conventionally used. In addition, the position control with a variable PI gain is applied to improve a dynamic response during a transient period and reduce vibration at a stop in case of matching position reference. The mentioned method can be used to estimate the commutation state and operate the high-precision position control for the ETC module and the high response characteristics. The validity of the proposed method is examined through the experimental results.