• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1804-1807
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• 1997

This paper presents a new approach to the design of cruise control system of a mobile robot with two drive wheel. The proposed control scheme uses a Gaussian function as a unit function in the fuzzy-neural network, and back propagation algorithm to train the fuzzy-neural network controller in the framework of the specialized learnign architecture. It is proposed a learning controller consisting of two neural networks-fuzzy based on independent reasoning and a connecton net with fixed weights to simply the neural networks-fuzzy. The performance of the proposed controller is shown by performing the computer simulation for trajectory tracking of the speed and azimuth of a mobile robot driven by two independent wheels.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.57
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• pp.123-129
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• 2000

The Bootstrap method proposed by Efron is non-parametric method which doesn't depend on the estimation of prior distribution refer to population. A typical statistical process control chart which is generally used is developed under the assumption that observations follow mutually independent and identically distributed within a sample and between samples. However, autocorrelation greatly affect the developed control chart under the assumption that observations are mutually independent. Many researchers showed that the result which was analyzed by using a typical control chart for the observations which has the correlation violated to the independence assumption can not be true. Therefore, we compared the standard method with bootstrap method and then evaluated them for x control chart and EWMA control chart by using bootstrap method which was proposed by Efron in the AR(1) model when the observations have correlation.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.3
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• pp.309-316
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• 2000

A coordination method for a macro/micro robot with separate controllers is proposed and evaluated. The macro/micro robot system generally has independent controllers for the macro and the micro robot respectively. A controller for the coordination of the macro and the micro robot has been designed based on the stable independent controller of each system. The method and trajectory generation method is also proposed to track the moving desired position rapidly. The control method and trajectory generation method is also proposed to track the moving desired position rapidly. The control strategy has been implemented to the macro/micron robot system to evaluate the performance. The experimental results show that the proposed method for maintaining the micro robot within its workspace has uniform performance over the various range of the bandwidth and the proposed trajectory generator is shown to be efficient.

• Journal of Industrial Technology
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• v.18
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• pp.289-293
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• 1998

In a independent joint servo control of robots, the performance of the control is influenced greatly by the joint interaction torques including Coriolis and centrifugal forces. These act as disturbance torques to the control system. As the speed of the robot increases, the effect of this disturbance torque increase, and makes the high speed - high precision control more difficult to achieve. In this paper, a solution to the optimal path placement problem is presented that minimizes the joint disturbance torque during a straight line motion. The proposed method is illustrated using computer simulation. The proposed solution method can be applied to the class of robots that are controlled by independent joint servo control, which includes the vast majority of industrial robots.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.17-24
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• 2006

Anti-lock brake system(ABS) are designed to prevent wheel lock on all wheels of the vehicle by sensing wheel angular speed, processing the speed sensor signals in suitable digital electronic control circuits and comanding electrohydraulic actuators to control brake pressure. This study considers a control of ABS using wheel circumferential acceleration thresholds which avoids dangerous wheel locking due to excessive brake pressure during the vehicle braking and discusses the 3-channels, 3-sensors ABS system that employs "independent control" technique for the front wheels and "select low" technique for the rear wheels. The validities of the ABS such as vehicle stability, steerability and stopping distance during braking are assured through the vehicle tests on uniform asphalt straight roads.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1733-1740
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• 2004

In the transverse flux linear induction motor(TFLIM) with the general secondary composed of conductor and back-yoke, there exists a magnetized force into the normal direction or the air-gap direction of the thrust motion as well as the thrust force. Therefore, the various methodologies have been tried to use the normal force by the two independent control variables of the multi-phase input. But, as the force depends inevitably and strongly on the thrust force, it is essential to decouple both forces for two control index. In this paper, we suggest a novel approach capable of compensating the couple between both forces and the control index by using the DC-biased multi-phase input, and then realizing the independent control of TFLIM.

• International Journal of Control, Automation, and Systems
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• v.4 no.6
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• pp.682-688
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• 2006

This paper deals with the delay-dependent and rate-independent stabilization of systems with multiple unknown time-varying delays and time-varying structured uncertainties. All the linear matrix inequalities based conditions are derived by employing free-weighting matrices to express the relationships between the terms in the Leibniz-Newton formula. The criteria do not require any tuning parameters. Numerical examples demonstrate the validity of the method.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.3
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• pp.9-15
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• 2017

In this study, set values of PICV(Pressure Independent Control Valve) were simulated according to the pressure distribution and velocity. The higher the set value and the open rate, as the lower the pressure in the neck. On the contrary, the lower the set value and open rate, as the higher the pressure in the neck. When the set value was small, the pressure was distributed sufficiently and confirmed that the pressure was generated by the VOF, confirming that it could generate a vapor pressure. When the set value 100 %, the lower corn open rate of the differential pressure was 46 % to 29 %, set value 100 % was 29 % to 19 %, and set value 6 % was 12 % to 6 % for the lower corn open rate percentile, it was limited to within 50 %. Thus, the results of this study on the correlation between open rate and differential pressure of the set value of the PICV will be beneficial to improve performance of flow control valves and contribute to their efficient operation used for a hydronic system.

• Journal of Distribution Science
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• v.14 no.10
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• pp.5-19
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• 2016

Purpose - This study conducts an empirical analysis of Korean hotel employees' perceived follower types and job attitudes and the influence of social relationships. Management methods are proposed based on the follower relationships. Research, data, and methodology - Data were collected from 400 surveys in eight top hotel restaurants in Seoul from March 16, 2016 to April 16, 2016. Of the 400, 359 valid surveys were used. The analysis was conducted using SPSS 19.0. Frequency and correlation, reliability and validity, and multiple regression tests were conducted. Results - Social relationships had a control effect on the relationship between follower types and job attitudes in terms of independent critical thinking and job satisfaction. For the social exchange relationship, active enthusiastic participation and job satisfaction had a control effect. The relationship of independent critical thinking and changes in career also had a control effect. There was no control effect in the relationship between active enthusiastic participation and motives for changing a career. Conclusion - By having followers with independent critical thinking and active enthusiastic participation, a company can achieve higher competitiveness.

• The Journal of Korea Robotics Society
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• v.15 no.3
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• pp.221-232
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• 2020

In a four-wheel independent drive platform, four wheels and motors are connected directly, and the rotation of the motors generates the power of the platform. It uses a skid steering system that steers based on the difference in rotational power between wheel motors. The platform can control the speed of each wheel individually and has excellent mobility on dirt roads. However, the difficulty of the straight-running is caused due to torque distribution variation in each wheel's motor, and the direction of rotation of the wheel, and moving direction of the platform, and the difference of the platform's target direction. This paper describes an algorithm to detect the slip generated on each wheel when a four-wheel independent drive platform is traveling in a harsh environment. When the slip is detected, a compensation control algorithm is activated to compensate the torque of the motor mounted on the platform to improve the trajectory tracking performance of the platform. The four-wheel independent drive platform developed for this study verified the algorithm. The wheel slip detection and the compensation control algorithm of the platform are expected to improve the stability of trajectory tracking.