• International Journal of Control, Automation, and Systems
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• 제2권3호
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• pp.343-353
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• 2004

This paper presents the survivability, mobility, and functionality of a rover as part of a radar system for polar regions. Rovers can provide autonomy and precision for radars used to measure ice thickness and other characteristics of ice sheets in Greenland and Antarctica. These rovers can be used to move radar antennas in precise patterns for synthetic aperture radars while providing environmental protection and power to the onboard radar equipment. This paper describes the mobility, actuation, sensing, winterization, control, and virtual prototyping of a polar rover. The rover has been successfully tested in Greenland.

• Ocean and Polar Research
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• 제36권4호
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• pp.465-473
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• 2014

This paper proposes a formation control method by which multi-mining robots maintain a specified formation and follow a path. To secure the path tracking performance, a pure-pursuit algorithm is considered for each individual robot, and to minimize the deviation from the reference path, speed reduction in the steering motion is added. For the formation, in which two robots are parallel in a lateral direction, the robots track the specified path at a constant distance. In this way, the Leader-Follower method is adopted and the following robot knows the position and heading angle of the leader robot. Through the experimental test using two ground vehicle models, the performance is verified.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1644-1645
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• 2007

This paper proposes an adaptive sliding mode control method for trajectory tracking of nonholonomic mobile robots with model uncertainties and external disturbances. The kinematic model represented by polar coordinates are considered to design a robust control system. Wavelet neural networks (WNNs) are employed to approximate arbitrary model uncertainties in dynamics of the mobile robot. From the Lyapunov stability theory, we derive tuning algorithms for all weights of WNNs and prove that all signals of an adaptive closed-loop system are uniformly ultimately bounded.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2381-2383
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• 2003

This paper presents an effective approach to dynamic obstacle avoidance for mobile robot. The main concept of this approach includes modified polar mapping for recognition of the moving obstacle in vision-based robot systems. To simplify the segmentation of the moving obstacle from the background and to obtain its relative position data the modified polar mapping is proposed. Dynamic moving obstacles are avoided with a vision sensor and stationary obstacles are avoided with a sonar sensor.

• 로봇학회논문지
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• 제3권3호
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• pp.186-193
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• 2008

We propose a novel real-time obstacle avoidance method for rescue robots. This method, named the ELA(Emergency Level Around), permits the detection of unknown obstacles and avoids collisions while simultaneously steering the mobile robot toward safe position. In the ELA, we consider two sensor modules, PSD(Position Sensitive Detector) infrared sensors taking charge of obstacle detection in short distance and LMS(Laser Measurement System) in long distance respectively. Hence if a robot recognizes an obstacle ahead by PSD infrared sensors first, and judges impossibility to overcome the obstacle based on driving mode decision process, the order of priority is transferred to LMS which collects data of radial distance centered on the robot to avoid the confronted obstacle. After gathering radial information, the ELA algorithm estimates emergency level around a robot and generates a polar histogram based on the emergency level to judge where the optimal free space is. Finally, steering angle is determined to guarantee rotation to randomly direction as well as robot width for safe avoidance. Simulation results from wandering in closed local area which includes various obstacles and different conditions demonstrate the power of the ELA.

• Ocean and Polar Research
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• 제37권1호
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• pp.73-80
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• 2015

In order to determine the appropriate volume of the a pressure compensator of deep seabed mining robots, this paper reports on an experimental test for oil volume change in an oil-filled box. At the design stage of underwater robots, it is crucial to determine the capacity of the hydraulic compensator which is replenished as much as the contracted oil volume of the robots. A pilot mining robot, MienRo was designed to work under 6,000 m in the deep sea. The hydraulic actuating oil and pressure compensating oil of MineRo may be exposed at a hydrostatic pressure environment of 600 bar. Although the oil can be assumed to be incompressible, its volume is actually changed under high pressure conditions due to air contained in the oil and oil contraction. To determine the capacity of the pressure compensator, the oil contraction rate should be verified through an experimental test using a hyperbaric chamber.

• 제어로봇시스템학회논문지
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• 제22권3호
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• pp.217-225
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• 2016

In this paper, we propose an improved path planning method and obstacle avoidance algorithm for two-wheel mobile robots, which can be effectively applied in an environment where obstacles can be represented by circles. Firstly, we briefly introduce the rapidly exploring random tree (RRT) and single polar polynomial (SPP) algorithm. Secondly, we present additional two methods for applying our proposed method. Thirdly, we propose a global path planning, smoothing and obstacle avoidance method that combines the RRT and SPP algorithms. Finally, we present a simulation using our proposed method and check the feasibility. This shows that proposed method is better than existing methods in terms of the optimality of the trajectory and the satisfaction of the kinematic constraints.