• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.08a
• /
• pp.23-26
• /
• 2003

An ultrasonic motor is a motor which uses vibration -a type of elastic vibration- to obtain a driving force, which then drives the motor using friction. In this paper, mode conversion type - single resonance mode ultrasonic rotary motor that use langevin type ultrasonic vibrator was studied. This model was proposed for the first time by Japanese Kumada in 1985. In this study, finite element analysis (FEA) of a stator and bidirectional driving characteristic of a rotor was newly obtained. The amplitude and phase of displacement and elliptical trajectory of beam was confirmed by FEA The fabricated motor was operated to clockwise and counterclockwise in 40.8 [kHz] and 44.2 [kHz] respectively. But bidirectional driving characteristics did not coincide each other.

• Journal of Korean Society of Transportation
• /
• v.23 no.5 s.83
• /
• pp.73-81
• /
• 2005

Triangle-shaped island was been used for the exclusive separation between the right-turn and the through flow. However, in case that existing Triangle-Shaped Island is built at the intersection of narrow road. there are more possibilities of traffic collision trespassing into the opposite lane. Accordingly, separation of the opposite lane is required so as to prevent the intrusion of the large-sized (a heavy) vehicle into the opposite lane turning at the intersection. This study showed the comparison between intersection composed of existing Triangle-Shaped Island and the intersection with Drop Island is added. First of all, in the safety aspect, a method to decide location and shape of Drop Island considering turning trajectory of the large-sized (the heavy vehicle) is addressed. The guideline on the placement of drop island install location and method to decide form the consider heavy truck's turn trajectory in safety side. As a conclusion. we analyzed that drop island is relatively superior to existing Triangle-Shaped Island in terms of driver, ease of driving, driving pleasantness, pedestrian, widening and economic performance aspect.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.5
• /
• pp.551-556
• /
• 2014

This paper proposes a balancing control and driving control of a bicycle robot based on dynamic modeling of the bicycle robot, which has been derived using the Lagrange equations. For the balancing control of the bicycle robot, a reaction wheel pendulum method has been adopted in this research. By using the dynamics equations of the bicycle robot, an LQR controller has been designed for a balancing and driving control of a bicycle robot. The performance of the balance control is verified experimentally before the driving control, which shows a stable posture within one degree vibrations. To show the dynamic characteristics of the bicycle robot during driving, a trapezoidal velocity trajectory is selected as the references. Through simulations and real experiments, the effectiveness of the proposed algorithm has been demonstrated.

• KIPS Transactions on Software and Data Engineering
• /
• v.3 no.9
• /
• pp.369-374
• /
• 2014

Path generation methods are required for safe and efficient driving in unmanned autonomous vehicles. There are two kinds of paths: global and local. A global path consists of all the way points including the source and the destination. A local path is the trajectory that a vehicle needs to follow from a way point to the next in the global path. In this paper, we propose a novel method for local path generation through machine learning, with an effective curve function used for initializing the trajectory. First, reinforcement learning is applied to a set of candidate paths to produce the best trajectory with maximal reward. Then the optimal steering angle with respect to the trajectory is determined by training an artificial neural network. Our method outperformed existing approaches and successfully found quality paths in various experimental settings, including the cases with obstacles.

• Journal of the Korean Society of Industry Convergence
• /
• v.19 no.2
• /
• pp.81-87
• /
• 2016

This paper presents a new approach to control of stable motion of single wheel driving robot system of a pitch that is controlled by an in-wheel motor and a roll that is controlled by a reaction wheel. This robot doesn'thave any actuator for a yaw axis control, which makes the derivation of the dynamics relatively simple. The Lagrange equations was applied to derive the dynamic equations of the one wheel driving robot to implement the dynamic speed control of the mobile robot. To achieve the real time speed control of the unicycle robot, the sliding mode control and optical regulator are utilized to prove the reliability while maintaining the desired speed tracking performance. In the roll controller, the sigmoid-function based robust controller has been adopted to reduce the vibration by the situation function. The optimal controller has been implemented for the pitch control to drive the unicycle robot to follow the desired velocity trajectory in real time using the state variables of pitch angle, angular velocity, angle and angular velocity of the driving wheel. The control performance of the control systems from a single dynamic model has been illustrated by the real experiments.

• Asian Journal of Business Environment
• /
• v.14 no.2
• /
• pp.1-10
• /
• 2024

Purpose: The purpose of this study is to investigate the essential factors contributing to the growth and success of smart cities, providing a comprehensive analysis of key elements that are crucial in fostering the development of smart cities. This study explored the impacts of technology-driven applications, corporate involvement, the role of experts, citizen co-creation, city-led strategy governance, and sustainable urban practices on overall attitudes towards smart cities. Additionally, the study examined the impact of overall attitude on the growth trajectory of the smart cities and satisfaction. Research design, data and methodology: To collect data, this study employed an online survey conducted by a reputable research organization. Data analysis involved the use of factor analysis, ANOVA, and regression analysis. Results: This study unveiled significant impacts of technology-driven applications, corporate involvement, the role of experts, citizen co-creation, city-led strategy governance, and sustainable urban practices on the overall attitudes. Furthermore, it demonstrated that the overall attitude significantly influences the growth trajectory of smart cities. Conclusions: This study identified key driving factors for smart city development, suggesting that the consideration of sustainable urban practices emerges as the most significant factor influencing the growth of the smart cities.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.10
• /
• pp.170-179
• /
• 2004

A vibration model of powder transfer equipment is developed by the lumped parameter method. A Powder transfer equipment does surging motion, bouncing motion and pitching motion. Motion equation becomes decoupling and removed vibration exciting source about pitching motion, and therefore designers presented the optimum design plan to be able to do adjustment with motion trajectory of powder transfer equipment. That is, way for design to be able to do motion trajectory of powder transfer equipment through change of design element as installation position and direction of motor, driving speed, mass unbalance, stiffness coefficient and installation position of support coil spring is presented. The design results, powder transfer equipment were able to know that fatigue destruction does not occur, and the reason is because maximum stress working on a basket structure is more very than fatigue strength small.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.566-569
• /
• 2000

This hybrid position/force control for the dynamic walking of the biped robot is performed in this paper. After the biped robot was modeled with 14 degrees of freedom of the multibody dynamics, the equations of motion are constructed using velocity transformation technique. Then the inverse dynamic analysis is performed for determining the driving torques and the ground reaction forces. From this analysis, obtains the maximum ground contact force at the moment of contacting which act on the rear of the sole of swing leg and the distribution curve of the ground reaction. Because these maximum force and distribution type acts an important role to the stability of the whole dynamic walking, they are reduced and distributed smoothly by means of the trajectory of the modified ground reaction force. This new trajectory is used to the reference input for more stable dynamic walking of the whole walking region.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.1
• /
• pp.35-42
• /
• 1998

This paper presents the introduction of Pseudo-2 axes robot module and its GA-based fuzzy control implementation. Pseudo-2 axes robot module which use a single motor and controller for driving 2 joints of a robot mechanism, is devised towards a lower priced robot with its degree of freedom maintained GA-based Fuzzy controller is considered for the better control implementation of the developed system than the conventional PID controller. Here. the scaling factors of the membership function with high fitness values are selected using a genetic algorithm for a pulse-type input trajectory. The obtained controller also shows better trajectory tracking performance than a PID controller.

• International Journal of Precision Engineering and Manufacturing
• /
• v.7 no.2
• /
• pp.56-59
• /
• 2006

A vibrational model of powder transfer equipment based on the lumped parameter method was developed, in which the operating motion consists of surging, bouncing, and pitching. After decoupling the equation of motion, the vibrational excitation source of the pitching motion was removed. So the designers are able to plan the optimum design to adjust the motion trajectory of the powder transfer equipment. That is, a procedure to adjust the motion trajectory of powder transfer equipment by changing design specifications such as the installation position, the direction of the motor, the driving speed, the mass unbalance, the stiffness coefficient, and the installation position of the support spring, is presented in this paper. The powder transfer equipment manufactured according to the results of this study did not suffer fatigue destruction, since the maximum stress on the basket structure was sufficiently small.