Byung-Ryong Lee

New lane detection algorithm for autonomous vehicles using computer vision

For navigation tasks it is necessary to determine position of the ego vehicle relative to the road. One of the principal approaches is to detect road boundaries and lanes using a vision system in the vehicle. This paper presents a simple and robust method designed to detect and estimate the curvature of road lane boundaries from images provided by a monocular camera. First, we use vector-lane-concept and non-uniform B-spline (NUBS) interpolation method to construct the boundaries road lane. Based on lane detection result, we estimate the curvature of left and right lane boundaries for autonomous guided vehicle systems application. Some experimental results based on real world road images are presented. These simulation results show the efficiency, feasibility and robustness of the algorithm.

Slip-ratio control of ABS using sliding mode control

In this paper, we propose a slip-ratio control of ABS using sliding mode control. The main control objective of ABS is to increase wheel tractive forces, which is conventionally done by controlling the wheel slip ratio around the peak of the /spl mu/-/spl lambda/ curve of the tractive forces during ABS maneuvers. Difficulties in designing an ABS controller are due to the nonlinear characteristics, the time-varying nature of the system components, and the unknown environmental parameters. In this paper, we apply a sliding mode control scheme to the ABS because it can give a robustness by invariance characteristic and order reduction, and the control scheme is verified through the several numerical simulations with Matlab/Simulink.

A Study on Optimization of fish robot velocity using Genetic Algorithm

Recently, the technologies of mobile robots have been growing rapidly in the fields such as cleaning robot, explosive ordnance disposal robot, patrol robot, and etc. However, the researches about the autonomous underwater robots have not been done so much, and they still remain at the low level of technology. In this paper, we studied the motion mechanism of real fishes, from which we derived the dynamic equations of a fish robot. Using the equation we developed a method to find the optimal parameters to give a maximum propulsive power for a considered fish robot. We used genetic algorithm and HCA(hill climbing algorithm) to find optimal value for maximum velocity of fish robot. Finally some experiments are carried out to compare the motion characteristics between experiment and simulation.

A study on energy saving algorithm of electro-pneumatic regulator with modified PWM driven method

The development of an accurate and energy saving electro-pneumatic regulator that may be applied to a variety of practical pressure control applications is described in this paper. A novel modified pulse width modulation (MPWM) valve pulsing algorithm allows the electro-pneu-matic regulator to become energy saving system. A comparison between the system response of conventional PWM algorithm and that of the modified PWM (MPWM) algorithm shows that the control performance is almost the same, but energy saving is greatly improved by adopting this new MPWM algorithm. The effectiveness of the proposed control algorithm is demonstrated through experiments with various reference trajectories.

Design and experimental evaluation of a robust force controller for a 6-link electro-hydraulic manipulator via h∞ control theory

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today’s highly information-oriented society and increasing demand of electric utilities. This maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulators because hydraulic manipulators have the advantage of electric insulation and power/mass density. Meanwhile an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous assembly tasks using hydraulic manipulators. In this paper, the robust force control of a 6-link electro-hydraulic manipulator system used in the real maintenance task of active electric lines is examined in detail. A nominal model for the system is obtained from experimental frequency responses of the system, and the deviation of the manipulator system from the nominal model is derived by a multiplicative uncertainty. Robust disturbance observers for force control are designed using this information in an H∞ framework, and implemented on the two different setups. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved even if the stiffness of environment and the shape of wall change.

A Study on the Motion Mechanism of Articulated Fish Robot

Recently, the technologies of mobile robots have been growing rapidly in the fields such as cleaning robot, explosive ordnance disposal robot, patrol robot, and etc. However, the researches about the autonomous underwater robots have not been done so much, and they still remain at the low level of technology. In this paper, we studied the motion mechanism of real fishes, from which we derived the dynamic equations of a fish robot. Using the equation we developed a method to find the optimal parameters to give a maximum propulsive power for a considered fish robot. The fished robot is model as a three jointed rigid bodies and its length is chosen as about 860 mm, based on the simulation result. Two servo motors with encoders are located at link 1 and link 2, respectively. However, the fourth link is connected to link 3 with a flexible springs to imitate the smooth motion of real fishes. Finally some experiments are carried out to compare the motion characteristics between experiment and simulation.

Design, Fabrication and Experimental Investigation of a Planar Pump Using Electro-Conjugate Fluid

This paper presents the design, fabrication, and experimental investigation of a novel planar pump using electro-conjugate fluid. The electro-conjugate fluid (ECF) is a kind of dielectric functional fluid which generates a powerful jet flow (ECF-jet) when a static electric field is applied via a pair of rod-like electrodes. This phenomenon that ECF can generate jet flows from the positive electrode to the ground electrode in an applied electric field is called the ECF effect, and converts electric energy directly into kinetic energy of the fluid. The ECF-jet acts directly on the working fluids; therefore, the proposed planar ECF pump requires no moving parts and produces no vibration or noise. The fabricated planar ECF pump consists of three parts: a pump base, a top cover, and an electrode substrate with dimensions of 280 mm × 190 mm × 1 mm. In this paper, five different electrode patterns and three different flow channel heights were investigated for the realization of a high-performance planar ECF pump. Each array of electrodes was patterned on the glass epoxy substrates using a wet-etching process, and the flow channel heights were either 200 μm, 300 μm, or 500 μm. The pumping experiments used FF-1EHA2 as the working fluid. Experimentation showed that a no-load flow rate of 5.5 cm3/s, maximum output pressure of 7.2 kPa, and maximum output power of 11.6 mW were achieved at an applied voltage of 2.0 kV.

A Study on the Pedestrian Detection on the Road Using Machine Vision

In this paper, we present a two-stage vision-based approach to detect multi views of pedestrian in road scene images. The first stage is HG (Hypothesis Generation), in which potential pedestrian are hypothesized. During the hypothesis generation step, we use a vertical, horizontal edge map, and different colors between road background and pedestrian`s clothes to determine the leg position of pedestrian, then a novel symmetry peaks processing is performed to define how many pedestrians is covered in one potential candidate region. Finally, the real candidate region where pedestrian exists will be constructed. The second stage is HV (Hypothesis Verification). In this stage, all hypotheses are verified by Support Vector Machine for classification, which is robust for multi views of pedestrian detection and recognition problems.

Automatic Thresholding Selection for Image Segmentation Based on Genetic Algorithm

In this paper, we focus on the issue of automatic selection for multi-level threshold, and we greatly improve the efficiency of Otsu`s method for image segmentation based on genetic algorithm. We have investigated and evaluated the performance of the Otsu and Valley-emphasis threshold methods. Based on this observation we propose a method for automatic threshold method that segments an image into more than two regions with high performance and processing in real-time. Our paper introduced new peak detection, combines with evolution algorithm using MAGA (Modified Adaptive Genetic Algorithm) and HCA (Hill Climbing Algorithm), to find the best threshold automatically, accurately, and quickly. The experimental results show that the proposed evolutionary algorithm achieves a satisfactory segmentation effect and that the processing time can be greatly reduced when the number of thresholds increases.

A Study on Optimization of Motion Parameters and Dynamic Analysis for 3-D.O.F Fish Robot

Recently, the technologies of mobile robots have been growing rapidly in the fields such as cleaning robot, explosive ordnance disposal robot, patrol robot, etc. However, the researches about the autonomous underwater robots have not been done so much, and they still remain at the low level of technology. This paper describes a model of 3-joint (4 links) fish robot type. Then we calculate the dynamic motion equation of this fish robot and use Singular Value Decomposition (SVD) method to reduce the divergence of fish robot’s motion when it operates in the underwater environment. And also, we analysis response characteristic of fish robot according to the parameters of input torque function and compare characteristic of fish robot with 3 joint and fish robot with 2 joint. Next, fish robot’s maximum velocity is optimized by using the combination of Hill Climbing Algorithm (HCA) and Genetic Algorithm (GA). HCA is used to generate the good initial population for GA and then use GA is used to find the optimal parameters set that give maximum propulsion power in order to make fish robot swim at the fastest velocity.