• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.726-730
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• 1990

In this paper, assuming that local range information is available, a collision-free path planning algorithm for multiple mobile robots is presented by using Hopfield neural optimization network. The energy function of the network is built using the present position and the goal position of each robot as well as its local range information. The proposed algorithm has several advantages such as the effective passing around obstacles with the directional safety distance, the easy implementation of robot motion planning including its rotation, the real-time path planning capability from the totally localized computations of path for each robot, and the adaptivity on arbitrary environment since any special shape of obstacles is not assumed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.896-901
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• 2008

This paper addresses the foot force distribution problem for quadruped robots with a failed leg. The quadruped robot has fault-tolerant straight-line gaits with one leg in locked-joint failure, and has discontinuous motion with respect to the robot body. The proposed method is operated in two folds. When the robot body stands still, we use the feature that there are always three supporting legs, and by incorporating the theory of zero-interaction force, we calculate the foot forces analytically without resort to any optimization technique. When the robot body moves, the conventional pseudo-inverse algorithm is applied to obtain the foot forces for supporting legs. Simulation results show the validity of the proposed scheme.

• Smart Structures and Systems
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• v.19 no.4
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• pp.403-413
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• 2017

The present article encompasses a nonlinear finite element (FE) and genetic algorithm (GA) based optimal vibration energy harvesting from nonprismatic piezo-laminated cantilever beams. Three cases of cross section profiles (such as linear, parabolic and cubic) are modelled to analyse the geometric nonlinear effects on the output responses such as displacement, voltage, and power. The simultaneous effects of taper ratios (such as breadth and height taper) on the output power are also studied. The FE based nonlinear dynamic equation of motion has been solved by an implicit integration method (i.e., Newmark method in conjunction with the Newton-Raphson method). Besides this, a real coded GA based constrained optimization scheme has also been proposed to determine the best set of design variables for optimal harvesting of power within the safe limits of beam stress and PZT breakdown voltage.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.71-79
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• 2014

This paper discusses a method for the determination of frequency control reserve requirement with consideration of the interaction between ex-ante planning and real-time balancing. In proposed method, we consider the fact that the delivered energy for tertiary control reserve is determined based on required capacity for secondary control reserve and the expected amount of load errors. Uncertain load errors are derived by Brownian motion, an optimization method is suggested using a stochastic programming. In a short, we propose an interactive dependent method for determining secondary control reserve requirement based on the principle that it satisfies to minimize the total cost. As a result, this paper provides will analyze for an example model to demonstrate the capabilities of the method.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.139-139
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• 2000

The subject of this paper is the tole operation for unmanned vehicle. The aim is studied in context of motor control system and algorithms for the mid to low level control of tele operation unmanned vehicle described. Modern, vehicle related researches have been implemented about control, chassis, body and safe쇼 but now is to driving comfort, I.T.S. and human factor, etc. As a result of this fact, unmanned vehicle is main research topic over the world but it is still very expensive and unreasonable. A hierarchical approach is studied in context of motor control system and algorithms for the mid to low level control of tele operation unmanned vehicle described. The real time control and monitoring of longitudinal, lateral, Pitching motion is to be solved by system integration and optimization technique. We show the experimental result about fixed brake range test and acceleration test. And all system is to integrated for driving simulator and unmanned vehicle.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.184-191
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• 2003

A parallel manipulator has high stiffness and all the joint errors on the device are not accumulated at the end -effector unlike a serial manipulator. These are the reasons why the parallel manipulator has been widely used in many fields of industry. In the parallel manipulator, it is very important to predict the exact pose of the end-effector when we want to control the end-effector motion. Installation errors have to be determined in order to predict and control the actual position and pose of the end-effector. This paper presents an algorithm to find the whole 36 joint error components with joint clearance errors and measurement errors considered, when a link length measurement sensor is used and data more than 36 times are acquired for 36 different configurations. A simulation test using this algorithm is performed with a Matlab program which uses the Levenberg-Marquardt method that is known to be efficient for non-linear optimization.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.247-254
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• 2003

The paper presents the influence of spring dynamics and friction on dynamic responses in a spring-driven cam system. The characteristics of the friction on the camshaft are analyzed using the nonlinear pendulum experiment while the parameters of the friction model are estimated using the optimization technique. The analysis reveals that the friction of the camshaft depends on stick-slip, Stribeck effect and viscous damping. Spring elements are found to have much influence on the dynamic characteristics. Hence, they are modeled as four-degree-of-freedom lumped masses with equivalent springs. The appropriateness of the derived friction model and spring model is verified by its application to a vacuum circuit breaker mechanism of the cam-follower type.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.464-466
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• 2014

The mechanism synthesis methods, graphical, analytical and computer-aided technique have been proposed for selecting and scaling mechanical system. According to developing computation tools, mechanism could be synthesized much faster and more correct than previous analytical ways by improved techniques. In this paper, the improved synthesis method is proposed to solve body guidance synthesis problem. To perform the mechanism synthesis for body guidance, a planar linkage is modeled as a set of free three bushings located in design space. The values of bushing stiffness and x, y position of bushings yielding a desired functional requirement related to input motion are found by using an optimization technique.

• The Journal of Korea Robotics Society
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• v.11 no.4
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• pp.217-225
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• 2016

Dynamic Positioning (DP) is used to automatically maintain the position and heading of a floating structure subjected to environmental disturbances. A DP control system is composed of a motion controller to compute the desired force and moment and a thrust allocator to distribute the computed force and moment to multiple thrusters considering mechanical and operational constraints. Among various thruster configurations, azimuth thrusters or propeller/rudder pairs tend to make the allocation problem difficult to solve, because these types of propulsion systems include nonlinear constraints. In this paper, a dynamic positioning strategy for a twin-thruster ship that is propelled by two azimuthing thrusters is addressed, and a thrust allocation method which does not require a numerical optimization solver is proposed. The applicability of the proposed method is demonstrated with an experiment using an autonomous boat.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.3
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• pp.171-179
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• 2015

Usually, in case of wind turbines on land, there are a lot of constraints for installation such as the insufficient installation space and noise pollution. On March 11, 2011, a nuclear leakage accident occurred due to the tsunami caused by the earthquake in Japan and then there have been a rapidly growing interest in floating offshore wind turbines. In this study, an optimization of the substructure of a semi-submersible type floating offshore wind turbine was made. Design variables were set and design alternatives were fixed. UOU-FAST was used for motion analysis in combined environmental conditions of waves and wind. Response Amplitude Operators(RAOs) were compared between the design alternatives.