• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.9
• /
• pp.893-897
• /
• 2008

To achieve the challenges of low-cost MEMS gyros for the precise self-localization of mobile robots, this paper examines an effective method of minimizing the drift on the heading angle that relies solely on integration of rate signals from a gyro. The main idea of the proposed approach is to use wavelet de-noising filter in order to reduce random noise which affects short-term performances. The proposed method was applied to Epson XV3500 gyro and the performances are verified by the comparisons with an existing commercial gyro module of vacuum cleaning robots.

• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.1
• /
• pp.66-73
• /
• 2016

An Inertial Measurement Unit (IMU)-based Attitude and Heading Reference System (AHRS) can calculate attitude and heading information with long-term accuracy and stability by combining gyro, accelerometer, and magnetic compass signals. Motivated by this characteristic of the AHRS, this paper presents a Motion-Tracking and Localization (MTL) method for a person or walking robot using multi-AHRSs. Five AHRSs are attached to the two calves, two thighs, and waist of a person/walking robot. Joints, links, and coordinate frames are defined on the body. The outputs of the AHRSs are integrated with link data. In addition, a supporting foot is distinguished from a moving foot. With this information, the locations of the joints on the local coordinate frame are calculated. The experimental results show that the presented MTL method can track the motion of and localize a person/walking robot with long-term accuracy in an infra-less environment.

• Journal of the Society of Naval Architects of Korea
• /
• v.59 no.5
• /
• pp.306-313
• /
• 2022

Most submarines use the cross-plane, which is convenient and inexpensive, but the number of submarines equipped with an X-plane is increasing recently. This study focuses on designing the control system of the X-plane submarine with various control methods and analyzing the effect of each controller. First, a maneuvering simulation environment for a subjected submarine is established. The dynamics and the operating range of control surfaces are considered. Second, a depth and heading control system of the submarine, which can be divided into three parts, is designed: guidance, controller, and control allocation. The guidance system generates a smooth desired depth and heading. The controller is designed using Proportional-Integral-Differential (PID), Linear Quadratic Regulator (LQR), and H-infinity (H∞) control methods. A linear control allocation method is used to distribute control moment calculated by the controller to the control surfaces. Finally, the designed control system is applied to a subjected X-plane submarine, and a depth and heading control simulations are performed. Each control method is compared and analyzed under various simulation conditions.

• International Journal of Ocean System Engineering
• /
• v.1 no.4
• /
• pp.192-197
• /
• 2011

This paper describes the mathematical modeling, control algorithm, system design, hardware implementation and experimental test of a Manta-type Unmanned Underwater Vehicle (MUUV). The vehicle has one thruster for longitudinal propulsion, one rudder for heading angle control and two elevators for depth control. It is equipped with a pressure sensor for measuring water depth and Doppler Velocity Log for measuring position and angle. The vehicle is controlled by an on-board PC, which runs with the Windows XP operating system. The dynamic model of 6DOF is derived including the hydrodynamic forces and moments acting on the vehicle, while the hydrodynamic coefficients related to the forces and moments are obtained from experiments or estimated numerically. We also utilized the values obtained from PMM (Planar Motion Mechanism) tests found in the previous publications for numerical simulations. Various controllers such as PID, Sliding mode, Fuzzy and $H{\infty}$ are designed for depth and heading angle control in order to compare the performance of each controller based on simulation. In addition, experimental tests are carried out in a towing tank for depth keeping and heading angle tracking.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.7
• /
• pp.95-102
• /
• 2016

Geomagnetic sensors are widely utilized for sensing heading direction of quadrotors. However, measurement from a geomagnetic sensor is easily corrupted by environmental magnetic field interference and roll/pitch directional motion. In this paper, a measurement method of a quadrotor heading direction is proposed for application to yaw attitude control. In order to eliminate roll/pitch directional motion effect, the geomagnetic sensor data is compensated using the roll/pitch angles measured for stabilization control. In addition, yaw-directional angular velocity data from a gyroscope sensor is fused with the geomagnetic sensor data using a complementary filter which is a simple and intuitive sensor fusion method. The proposed method is applied to experiments, and the results are presented to prove validity and effectiveness of the proposed method.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.37 no.3
• /
• pp.189-194
• /
• 2017

The present study analyzes the role of Lactic Acid Bacteria Mixture (LBM) on improving rye silage quality. Rye of four different stages (Booting, Heading, Flowering, and Late flowering) was collected and silage was prepared. The nutrient profile analysis of experimental silage groups showed no significant changes between control and LBM inoculation. Interestingly, the pH of rye silage in LBM treatments showed significant reduction than control (p<0.05) in all stages of rye silage. However, lowest pH (3.69) resulted on booting stage among other stages of rye. Subsequently significant lactic acid production was noted in all stages of LBM inoculation than control. Conversely maximum lactic acid production of (5.33%DM) was noted at booting stage followed by (4.86%DM) in heading stage. Further the lactic acid bacterial (LAB) count in LBM inoculated group showed significant increase than control. Similarly, the silage of booting stage group registered maximum LAB population ($63.7{\times}10^6CFU/g$) after that heading stage ($32.3{\times}10^6CFU/g$). Further significant reduction in yeast growth and no fungal growth was noted in all LPM treatment groups. Hence, LBM inoculants could be a better additive for improving rye silage quality.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.10a
• /
• pp.42-43
• /
• 2010

In this paper, automatic control system for the Manta UUV are constructed for the diving and steering maneuver. PID controller and Fuzzy controller are adopted in this system. Based on the 6DOF dynamic equation, simulation program has been developed using the Matlab. Using this program, depth control system and heading control system with tidal current are evaluated.

• Journal of the Korean Society for Library and Information Science
• /
• v.25
• /
• pp.233-264
• /
• 1993

The authorized form is called the heading must be unique and consistent. Without both uniqueness and cosistency, retrieval from the bibliographic database will not be optimal and in some cases may even be impossible. But the authority control is extremely expensive, because it is labour-intensive and dependent on professional investigation and judgement. In fact, it is by far the most expensive function in all of bibliographic control. The processes used to determine the form of access points. maintain. use. and evaluate very accurate authority records reduce the efficiency to generate or merge bibliographic items without modification from any national level bibliographic utilities as well as individual library. In this paper non-authority control system was suggested to solve the disadvantages of authority work. The apparent advantages of the non-authority control system are it is easy to determine the heading, input the bibliographic data. integrate the access points into an existing file, and generate and merge bibliographic data without modification. In addition, non-authority control system can be transmitted into online information retrieval system conducted with a mixture of controlled vocabularies and natural language.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.4
• /
• pp.363-368
• /
• 2005

This paper proposes an LOS(line-of-sight) guidance system of a ship for path following. From the viewpoint of a control configuration, guidance is a special type of compensation algorithm that is placed in front of the controller to accomplish navigational objects. A guidance system generates a reference trajectory for trajectory tracking or path control and decides the desired velocity, position and heading angle. A control system executes commands based on a reliable guidance law during navigation. An LOS vector from the vessel to a point on the path between two way-points in straight-line navigation or a point among turning circle in turning navigation is selected, and then a heading angle is calculated to converge the desired path based on the LOS vector. The LOS guidance law is defined for the straight-line and the turning circle, respectively. The effectiveness of the suggested LOS guidance system is assured through computer simulation.

• Journal of Hydrospace Technology
• /
• v.1 no.1
• /
• pp.75-88
• /
• 1995

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship's direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dimension in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.