• The Journal of Korea Robotics Society
• /
• v.5 no.4
• /
• pp.294-301
• /
• 2010

In order to produce a convenient robot for the aged and the lower limb disabled, it is needed for the research detecting implicit walking intention and controlling robot by a user's intention. In this study, we developed sensor module system to control the walking- assist robot using FSR sensor and tilt sensor, and analyzed the signals being acquired from two sensors. The sensor module system consisted of the assist device control unit, communication unit by wire/wireless, information collection unit, information operation unit, and information processing PC which handles integrated processing of assist device control. The FSR sensors attached user's the palm and the soles of foot are sensing force/pressure signals from these areas and are used for detecting the walking intention and states. The tilt sensor acquires roll and pitch signal from area of vertebrae lumbales and reflects the pose of the upper limb. We could recognize the more detailed user's walking intention such as 'start walking', 'start of right or left foot forward', and 'stop walking' by the combination of FSR and tilt signals can recognize.

• Proceedings of the Korean Society of Tobacco Science Conference
• /
• 1999.10a
• /
• pp.9-12
• /
• 1999

Up to the 60's cigarette paper commercial grades were simply described as ' non combustible ', ' combustible ' or ' extra-combustible '. It was assumed that combustibility of the paper itself was correlated with cigarette combustibility. Since then, the characteristics of cigarette paper, like natural porosity and burning additives, which influence truly cigarette combustibility, have been described by various authors and it became clear to cigarette designers that paper combustibility was not generally a significant factor governing cigarette combustibility. On the other hand, for Roll Your Own(RYO)wrapping papers, the ECPCI has proposed to the CORESTA RYO Task Force to use paper combustibility, and specially the LCT test, to classify papers between low and high smoke delivery, and a new Task Force on PAPER COMBUSTIBILITY was recently set up to develop a recommended method. The objective of this presentation Is to show results demonstrating that for paper used on cigarettes, there is NO GENERAL CORTRELATION between PAPER and CIGARETTE combustibility. We will also show results confirming that, for the specific group of RYO booklet papers containing no burning additives, there is a correlation between paper combustibility and FCSA's Combustibility/smoke delivery. This apparent discrepancy will be explained by reviewing the role played by the various characteristics of cigarette paper in governing cigarette combustibility.

• Korean Chemical Engineering Research
• /
• v.53 no.1
• /
• pp.111-115
• /
• 2015

To produce patterns with high resolution in gravure printing, it is important to increase ink transfer ratio. The ink which has higher affinity with substrate can be transferred more from the roll to the substrate due to the good wettability between ink and substrate. However, it is difficult to evaluate the affinity between the substrate and the ink which is viscoelastic in nature. In this study, we suggest a practical method to evaluate the interfacial interaction between the ink and various substrates.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.1
• /
• pp.87-93
• /
• 2014

Conventional two-wheeled balancing robots are limited in terms of turning speed because they lack the lateral motion to compensate for the centrifugal force needed to stop rollover. In order to improve lateral stability, this paper suggests a two-wheeled balancing mobile platform equipped with a tilting mechanism to generate roll motions. In terms of static force analysis, it is shown that the two-body sliding type tilting method is more suitable for small-size mobile robots than the single-body type. For the mathematical modeling, the tilting-balancing platform is assumed as a 3D inverted pendulum and the four-degrees-of-freedom equation of motion is derived. In the velocity/posture control loop, the desired tilting angle is naturally determined according to the changes of forward velocity and steering yaw rate. The efficiency of the developed tilting type balancing mobile platform is validated through experimental results.

• International Journal of Ocean System Engineering
• /
• v.1 no.4
• /
• pp.222-229
• /
• 2011

In this paper, we present the concept and main mission of the Crabster, an underwater walking robot. The main focus is on the modeling of drag and lift forces on the legs of the robot, which comprise the main difference in dynamic characteristics between on-land and underwater robots. Drag and lift forces acting on the underwater link are described as a function of the relative velocity of the link with respect to the fluid using the strip theory. Using the translational velocity of the link as the rotational velocity of the joint, we describe the drag force as a function of joint variables. Generalized drag torque is successfully derived from the drag force as a function of generalized variables and its first derivative, even though the arm has a roll joint and twist angles between the joints. To verify the proposed model, we conducted drag torque simulations using a simple Selective Compliant Articulated Robot Arm.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1303-1309
• /
• 2003

This paper presents the static and dynamic measurements for the strength and motion characteristics as well as the improved procedures to assess strength of wheel loaders. Two scenarios for static measurement were decided by which cylinder was actuating. The dynamic measurement was performed for two types of motion, that is, simple reciprocation of the working devices and actual working motion including traveling, digging and dumping. The measured items were stresses, cylinder pressures and strokes. Stress induced by bucket working showed higher level than that by boom working. The measured cylinder speeds were relatively superior to the design speeds. Working stress histories were thought to be closer to static rather than dynamic. A fully assembled FE model was prepared for structural analysis. In this paper, a more simple method was suggested to avoid nonlinearity caused by heave of rear frame under digging forces. Also how brake affected on structural behavior and digging force was examined closely in relation with tire pressure. It was confirmed that the overall stress level of wheel loader during turning traveling with loaded bucket was far lower than the yield stress of material.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.2
• /
• pp.47-55
• /
• 2012

This work deals with dynamic analysis of a monorail system with magnetic caterpillar where magnets are embedded inside each articulated element of the caterpillar, augmenting traction force of main rubber wheels to climb up slope up to 15 degree grade. Considerations are first given to determine stiffness of the primary and secondary suspension springs in order for the natural frequencies of car body and bogie associated with vertical, pitch, roll and yaw motion to be within generally accepted range of 1-2 Hz. Equations for calculating magnetic force needed to climb up given slope are derived, and a magnetic caterpillar system for 1/6 scale monorail is designed based on the derivation. To assess the hill climbing ability and cornering stability, and make sure smooth operation of the side and vertical guiding wheels which is critical for safety, a multibody model that takes into account of every component level design characteristics of car, bogie, and caterpillar is set up. Through hill climbing simulation and comparison with measurement of the limit slope, the validity of the analysis and design of the magnetic caterpillar system are demonstrated. Also by studying the curving behavior, maximum curving speed without rollover, functioning of lateral motion constraint system, the effects of geometry of guiding rails are studied.

• The Journal of Korea Robotics Society
• /
• v.13 no.2
• /
• pp.103-112
• /
• 2018

In this paper, a high performance underwater vehicle which can be manufactured at low cost is designed and fabricated, and its performance is verified through experiments. To improve efficiency, the Myring equation is used to design the appearance and the duct structure including the thruster is planned to increase the propulsion efficiency while reducing the drag force. Through various methods, it is secured stable waterproof performance, and also is devised to have high speed movement and turning performance. The developed underwater vehicle is equipped with a high output BLDC motor to achieve a linear speed of up to 2 m/s and can change direction rapidly with stability through four rudders. The rudders are driven by coupling a timing belt and a pulley by extending the axis of a servo motor, and are equipped at the end of the body to turn heading. In addition, for stable posture control, the roll keeps its internal center of gravity low and maintains its stability due to restoring force. By controlling the four rudders, pitch and yaw are handled by the PID controller and show stable performance. To investigate the horizontal turning performance, it is confirmed that the yaw rate controller is designed and stable yaw rate control is performed.

• The Journal of Korea Robotics Society
• /
• v.18 no.3
• /
• pp.241-250
• /
• 2023

This paper describes the posture stabilization control of a bipedal transformer robot being developed for military use. An inverted pendulum model with a rectangular that considers the robot's inertia is proposed, and a posture stabilization moment that can maintain the body tilt angle is derived by applying disturbance observer and state feedback control. In addition, vertical force and posture stabilization moments that can maintain the body height and balance are derived through QP optimization to obtain the necessary torques and vertical force for each foot. The roll and pitch angles of the IMU sensor attached to the robot's feet are reflected in the ankle joint to enable flexible adaptation to changes in ground inclination. Finally, the effectiveness of the proposed algorithm in posture stabilization is verified by comparing and analyzing the difference in body tilt angle due to disturbances and ground inclination changes with and without algorithm application, using Gazebo dynamic simulation and a down-scale test platform.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.13 no.1
• /
• pp.889-901
• /
• 2021

The tension of cables and motion response significantly affect safety of an immersed tunnel element in the immersion process. To investigate those, a hydrodynamic scale-model test was carried out and the model experiments was conducted under wind, current and wave loads simultaneously. The immersion standby (the process that the position of the immersed tunnel element should be located before the immersion process) and immersion process conditions have been conducted and illustrated. At the immersion standby conditions, the maximum force of the cables and motion is much larger at the side of incoming wind, wave and current, the maximum force of Element-6 (6 cables directly tie on the element) is larger than for Pontoon-8 (8 cables tie on pontoon of the element), and the flexible connection can reduce the maximum force of the mooring cables and motion of element (i.e. sway is expecting to decrease approximate 40%). The maximum force of the mooring cables increases with the increase of current speed, wave height, and water depth. The motion of immersed tunnel element increases with increase of wave height and water depth, and the current speed had little effect on it. At the immersion process condition, the maximum force of the cables decrease with the increase of immersion depth, and dramatically increase with the increase of wave height (i.e. the tension of cable F4 of pontoons at wave height of 1.5 m (83.3t) is approximately four times that at wave height of 0.8 m). The current speed has no much effect on the maximum force of the cables. The weight has little effect on the maximum force of the mooring cables, and the maximum force of hoisting cables increase with the increase of weight. The maximum value of six-freedom motion amplitude of the immersed tunnel element decreases with the increase of immersion depth, increase with the increase of current speed and wave height (i.e. the roll motion at wave height of 1.5 m is two times that at wave height of 0.8 m). The weight has little effect on the maximum motion amplitude of the immersed tunnel element. The results are significant for the immersion safety of element in engineering practical construction process.