• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2365-2368
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• 2001

This paper describes a fuzzy steering controller for an autonomous mobile robot with MR sensor. Using the magnetic field($B_{x}$, $B_{y}$, $B_{z}$) obtained from the MR sensor, we designed fuzzy controller for driving on the road center. Fuzzy rule base was built to magnetic field($B_{x}$, $B_{y}$, $B_{z}$). To develop an autonomous mobile robot simulation program, we have done modeling MR sensor, dynamic model of mobile robot and coordinate transformation. A computer simulation of the robot (including mobile robot dynamics and steering) was used to verify the steering performance of the mobile robot controller using the fuzzy logic. Good results were obtained by computer simulation. So, we confirmed the robustness of the proposed fuzzy controller by computer simulation. Also, we know that proposed control algorithm was applied to real autonomous mobile robot.

• Journal of Information Processing Systems
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• v.14 no.4
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• pp.948-960
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• 2018

Many mobile sensing frameworks have been developed to help researcher doing their mobile sensing research. However, energy consumption is still an issue in the mobile sensing research, and the existing frameworks do not provide enough solution for solving the issue. We have surveyed several mobile sensing frameworks and carefully chose one framework to improve. We have designed an adaptive sampling module for a mobile sensing framework to help solve the energy consumption issue. However, in this study, we limit our design to an adaptive sampling module for the location and motion sensors. In our adaptive sampling module, we utilize the significant motion sensor to help the adaptive sampling. We experimented with two sampling strategies that utilized the significant motion sensor to achieve low-power consumption during the continuous sampling. The first strategy is to utilize the sensor naively only while the second one is to add the duty cycle to the naive approach. We show that both strategies achieve low energy consumption, but the one that is combined with the duty cycle achieves better result.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.319-325
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• 2008

In this paper, we develop the multi sensor system, to get the sufficient information of mobile robot's environment. Mobile robot user interface, based on multi sensor system, can choice a suitable sensor by low-cost multi sensors and then acquisition information from remote robot's workspace using auto sequencing user display function. This research of multi sensor system is consists of ultrasonic sensor, position sensing detector, and low-cost CMOS camera module.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.2
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• pp.30-38
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• 2003

This paper proposed PID controller for torch slider and PD controller for motor right wheel. to control the motion of two-wheeled welding mobile robot with seam tracking sensor touched on welding line. The motion control is realized in the view of keeping constant welding velocity and precise seam tracking even though the target welding line is on straight line or curved line. The position and direction of the body of the mottle robot are controlled by using signal errors between seam tracking sensor and body positioning sensor attached on the end of torch slider and body side of the mobile robot, respectively. In turning motion, the body and the torch slider are controlled by using the kinematic model related with two motions of body turning and torch sliding. The straight locomotion is controlled according to eleven control patterns obtained from displacements between two sensors of the seam tracking sensor and the body positioning sensor. The effectiveness is proven through the experimental results fur lattice type welding line. Through the experimental results, we can see that the position value of the electrode end point and the welding velocity are controlled almost constantly both in straight and turning locomotion.

• Journal of Korea Multimedia Society
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• v.21 no.6
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• pp.667-677
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• 2018

Since sensor networks consist of sensor nodes with limited energy resources, so efficient energy use of sensor nodes is very important in the design of sensor networks. Sensor nodes consume a lot of energy for data transmission. Clustering technique is used to efficiently use energy in data transmission. Recently, mobile sink techniques have been proposed to reduce the energy load concentrated on the cluster header near a sink node. The CMS(Cluster-based Mobile sink) technique minimizes the generation of control messages by creating a data transmission path while creating clusters, and supports the inter-cluster one-hop transmission. But, there is a case where there is no connectivity between neighbor clusters, it causes a problem of having a long hop data transmission path regardless of local distance. In this paper, we propose a SCBC(Strong connection balancing cluster) to support the path of the minimum number of hops. The proposed scheme minimizes the number of hops in the data transmission path and supports efficient use of energy in the cluster header. This also minimizes a number of hops in data transmission paths even when the sink moves and establishes a new path, and it supports the effect of extending the life cycle of the entire sensor network.

• Journal of the Korea Society for Simulation
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• v.15 no.4
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• pp.107-117
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• 2006

Wireless Sensor Network consists of sensor nodes and sink. A sink receives and processes signals created from sensor nodes. Many studies have been performed, since sensor network allows multiple nodes to run using a limited amount of energy, Most researches have focused on using fixed sink. However, in many cases, the sink has mobility effected by man, cars, and etc. This research proposes three methods for reducing the node's energy consumption which is applied the Grid method based on mobile sink. Most routing processes handled by the mobile sink and wireless sensor area is separated and operated respectively. So, this research allows decreasing the power costs. In addition, it also proposes methods using simulation to test the quality of the performance.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.38-43
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• 2017

Sensor Networks (WSNs) can be defined as a self-configured and infrastructure-less wireless networks to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants and to cooperatively pass their data through the network to a main location or base-station where the data can be observed and analyzed. Typically a wireless sensor network contains hundreds of thousands of sensor nodes. The sensor nodes can communicate among themselves using radio signals. A wireless sensor node is equipped with sensing and computing devices, radio transceivers and power components. The individual nodes in a wireless sensor network (WSN) are inherently resource constrained: they have limited processing speed, storage capacity, communication bandwidth and limited-battery power. At present time, most of the research on WSNs has concentrated on the design of energy- and computationally efficient algorithms and protocols In order to extend the network life-time, in this paper we are looking into a routing protocol, especially LEACH and LEACH-related protocol. LEACH protocol is a representative routing protocol and improves overall network energy efficiency by allowing all nodes to be selected to the cluster head evenly once in a periodic manner. In LEACH, in case of movement of sensor nodes, there is a problem that the data transmission success rate decreases. In order to overcome LEACH's nodes movements, LEACH-Mobile protocol had proposed. But energy consumption increased because it consumes more energy to recognize which nodes moves and re-transfer data. In this paper we propose the new routing protocol considering nodes' mobility. In order to simulate the proposed protocol, we make a scenario, nodes' movements randomly and compared with the LEACH-Mobile protocol.

• The Journal of Korea Robotics Society
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• v.2 no.4
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• pp.317-326
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• 2007

Recently, robotic automation in clinical laboratory becomes of keen interest as a fusion of bio and robotic technology. In this paper, we present a new robotic platform for clinical tests suitable for small or medium sized laboratories using mobile robots. The mobile robot called Mobile Agent is designed as transfer system of blood samples, reagents, microplates, and any instruments. Also, the developed mobile agent can perform diverse tests simultaneously based on its cooperative and distributed ability. The driving circuits for the mobile agent are embedded in the robot, and each mobile agent communicates with other agents by using Bluetooth communication. The RFID system is used to recognize patient information. Also, the magnetic hall sensor is embedded to remove and compensate the cumulated error of locomotion at the bottom of mobile agent. The proposed mobile agent can be easily used for various applications because it is designed to be compatible with general software development tools. The Mobile agents are manufactured, and feasibility of the robot and localization of the agents using magnetic hall sensor are validated by preliminary experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4738-4753
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• 2018

Efficient rendezvous node selection and routing algorithm (RNSRA) for wireless sensor networks with mobile sink that visits rendezvous node to gather data from sensor nodes is proposed. In order to plan an optimal moving tour for mobile sink and avoid energy hole problem, we develop the RNSRA to find optimal rendezvous nodes (RN) for the mobile sink to visit. The RNSRA can select the set of RNs to act as store points for the mobile sink, and search for the optimal multi-hop path between source nodes and rendezvous node, so that the rendezvous node could gather information from sensor nodes periodically. Fitness function with several factors is calculated to find suitable RNs from sensor nodes, and the artificial bee colony optimization algorithm (ABC) is used to optimize the selection of optimal multi-hop path, in order to forward data to the nearest RN. Therefore the energy consumption of sensor nodes is minimized and balanced. Our method is validated by extensive simulations and illustrates the novel capability for maintaining the network robustness against sink moving problem, the results show that the RNSRA could reduce energy consumption by 6% and increase network lifetime by 5% as comparing with several existing algorithms.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.570-574
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• 1993

This paper proposes a new method of estimating the position and heading angle of a mobile robot moving on a flat surface. The proposed localization method utilizes two passive beacons and a single rotating ultrasonic sensor. The passive beacons consist of two cylinders with different diameters and reflect the ultrasonic pulses coming from the sonar sensor mounted on the mobile robot. The geometric parameter set of beacon is acquired from the sonar scan data obtained at a single mobile robot location using a new data processing algorithm. Form this parameter set, the position and heading angle of the mobile robot is determined directly. The performance and validity of the proposed method are evaluated using two beacons and a single sonar sensor attached at the pan-tilt device mounted on a mobile robot, named LCAR, in our laboratory.