• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.131-136
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• 1988

In this paper we describe a motion control algorithm for a 4-legged robot over slopped terrain and steps. The new concept of the mechanically constrained angle has been introduced and the algorithm has been developed based on the relationship between the gait stability margin and the slope angle. The result then has been extended to the case where the robot walks over steps.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.6
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• pp.673-678
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• 2011

This paper analyzes the standing balance of four-legged robots which are useful for delivering objects or investigating of information. For this, we specify an effective model of general four-legged robots and propose a boundary condition based on the standing stability of the four-legged walking. To verify such a standing balance, we consider some exemplary free motions at the standing mode of the robot and discuss on the robot's balance margin. The analysis specified in this paper will be applicable for effective balancing control of various quadruped robotic walking.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.138-147
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• 1999

For autonomous navigation, a legged robot should be able to walk over irregular terrain and adapt itself to variation of supporting surface. Walking through slope is one of the typical tasks for such case. Robot needs not only to change foot trajectory but also to adjust its configuration to the slope angle for maintaining stability against gravity. This paper suggests such adaptation algorithm for stable walking which uses feedback of reaction forces at feet. Adjusting algorithm of foot trajectory was studied with the estimated angel of slope without visual feedback. A concept of virtual slope angle was introduced to adjust body configuration against slope change of the supporting terrain. Regeneration of foot trajectory also used this concept for maintaining its stable walking against unexpected landing point.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.6
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• pp.626-633
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• 2009

A motion planning algorithm is presented in this paper for a commercialized quadruped walking of robot pet. Stable walking is the basic requirement for a commercial-purpose legged robot. In order to secure the walking stability, modified body sway to the centroid of support polygon is addressed. By representation of walking motion with respect to the world coordinate system rather than body coordinate, it is possible to design the several gaits in unified fashion. The initial gait posture is introduced to maximize the stride and to achieve fast walking. The proposed walking motion planning is verified through computer simulation and experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.589-590
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.490-496
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• 1995

A four-legged mobile robot can move on the plain terrain with mobility and stability, but if there exist any obstacles on the terrain of the motion direction, it takes extra times for a mobile robot to cross those obstacles and the stability should be considered during motion. The main objevtive is the study of a quadruped which can cross obstacles with better mobility, stability and fuel economy than any other wheeled or tracked vehicles. Vertical step, isolated wall and ditch are the basic obstacles and by understanding those three cases perfectly, a quadruped can move on any mixed rough terrain as 4-legged animal moves. Each leg of a determine the crossing capability in a static analysis. A quadruped can be simplified with links and joints. By applying the research method, a quadruped can determine the control procedures as soon as it receives the terrain informations from scanner and finally can be moved as animals move with mobility and stability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.11
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• pp.1326-1331
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• 2009

The sensor data measured by the legged robot are used to recognize the physical environment or information that controls the robot's posture. Therefore, a robot's ambulation can be advanced with the use of such sensing information. For the precise control of a robot, highly accurate sensor data are required, but most sensors are expensive and are exposed to excessive load operation in the field. The seriousness of these problems will be seen if the prototype's practicality and mass productivity, which are closely related to the unit cost of production and maintenance, will be considered. In this paper, the use of a virtual sensor technology was suggested to address the aforementioned problems, and various ways of applying the theory to a walking robot obtained through training with an actual sensor, and of various hardware information, were presented. Finally, the possibility of the replacement of the ground reaction force sensor of legged robot was verified.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.825-837
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• 2017

This paper describes a novel type of a walking rehabilitation robot that applies robot technologies to crutches used by patients with walking difficulties in the lower body. The primary features of the developed robot are divided into three parts. First, the developed robot is worn on the patient's chest, as opposed to the conventional elbow crutch that is attached to the forearm; hence, it can effectively disperse the patient's weight throughout the width of the chest, and eliminate the concentrated load at the elbow. Furthermore, it allows free arm motion during walking. Second, the developed robot can recognize the walking intention of the patient from the magnitude and direction of the ground reactive forces. This is done using three-axis force sensors attached to the feet of the robot. Third, the robot can perform a stair walking function, which can change vertical movement trajectories in order to step up and down a single stair according to the floor height. Consequently, we experimentally showed that the developed robot can effectively perform walking rehabilitation assistance by perceiving the walking intention of the patient. Moreover we quantitatively verified muscle power assistance by measuring the electromyography (EMG) signals of the muscles of the lower limb.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.353-358
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• 2011

This paper presents a virtual-legged walking model for bipedal robots and analyzes its fundamental RPY(Roll, Pitch, and Yaw) motion effects by simulation. For the purpose of identifying the motion effects of the bipedal walking, we assign some arbitrary trajectories both at the center of mass and at the center of pressure of the robot based on human walking. And then we verify the major moments to the roll, pitch, and yaw directions of the robot. As a result, it is shown that those motions are natural in the process of bipedal walking and they are deeply dependent on the step distance, the vertical level of the center of mass, and the acceleration of the robot. The importance of trajectory planning for the footstep location during a bipedal walking is finally addressed in terms of balance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1247-1252
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• 2005

Though a legged robot has a high terrain adaptability as compared with a wheeled robot, its moving speed is considerably low in general. For attaining a high moving speed with a logged robot, a dynamically stable walking is a promising solution. However, the energy efficiency of a dynamically stable walking is generally lower than the efficiency of a stable gait such as a crawl gait. In this paper, energy consumption of two walking patterns for a trot gait is simulated through modeling a quadruped walking robot named TITAN-VIII.