• Journal of Institute of Control, Robotics and Systems
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• v.12 no.3
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• pp.233-240
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• 2006

This paper presents the robust control method using a self recurrent wavelet neural network (SRWNN) via adaptive backstepping design technique for stable walking of biped robots with unknown model uncertainties. The SRWNN, which has the properties such as fast convergence and simple structure, is used as the uncertainty observer of the biped robots. The adaptation laws for weights of the SRWNN and reconstruction error compensator are induced from the Lyapunov stability theorem, which are used for on-line controlling biped robots. Computer simulations of a five-link biped robot with unknown model uncertainties verify the validity of the proposed control system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.743-747
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• 2000

The coordinated mechanism of terrestrial vertebrates enables them to maneuver over all of the terrain conditions since they have a distinct ability to adapt to varying conditions. Their locomotions remain infinitely more advanced and elegant than that of present-day existing mechanical walking robots. However, the principles of existing walking robots are based more on technical rather than on biological concepts, yielding unstable locomotion with low speed. In order to apply these advanced biological phenomena to the mechanical design of 4-legged walking robot, modeling methods are introduced and mathematical equations are also introduced.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.2
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• pp.100-105
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• 2013

In this study, we analyze the balance of quadruped walking robots. For this purpose, a simplified polygonal model of a quadruped walking configuration is considered. A boundary-range-based balance margin is used for determining the system stability of the polygonal walking configuration considered herein. The balance margin enables the estimation of the walking configuration's balance for effective walking. The usefulness of the balance margin is demonstrated through exemplary simulations. Furthermore, balance compensation by means of foot stepping is addressed.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.876-881
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• 2008

When biped robots speed up to run and reduce speed to walk after running, it needs stable speed translation. This paper proposed simple speed translation using the modified LIPM (Linear Inverted Pendulum Mode). We can change stride and period time of a biped robot in some bounded sets with this propose algorithm. This method is simple and effective in simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.69-73
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• 1987

In this paper the continuous static stable gait, kinematics and the basic control algorithm of the quadruped walking robot have been discussed. The control method described in this paper will be extended for the walking robot to walk on an uneven terrain.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1395-1403
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• 2016

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2248-2253
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• 2005

Although the progress in bipedal walking is impressive in recent years, biped robots still require very high torque and can walk only for a short time interval with their internal batteries. Therefore, further research needs to be carried out to enhance walking efficiency of these robots. In order to achieve this goal, we attempt to imitate human walking with pelvis and waist joint rotations in the frontal plane. In order to investigate the effect of the pelvis and waist joint rotations in the frontal plane motion, we study the frontal plane model with a triangular structure made up of a waist joint and two hip joints. Through simulation, we show that the pelvis rotation can reduce the maximum torque and the control effort, and the waist joint rotation can reduce the trunk sway caused by the pelvis rotation. The combination of these two rotations makes the bipedal walking in the frontal plane more efficient.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.4
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• pp.299-309
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• 2014

When biped robots make turns, the ability to walk stably and precisely along any circular path is crucial. In this context, inverse kinematics solutions are found for accurate gait realization, and new zero moment point(ZMP) equations are derived with respect to the cyclindrical coordinate system to facilitate generation of stable walking patterns. Then, appropriate steady and transitional walking patterns are both proposed in form of time functons. Subsequently, walking patterns for a path but of different speeds are generated using the functions and associated formulas, and preliminarily checked for stability based on the ZMP equations. Upon comparison of those cases, one can see how and when robots may fall down during circular walking. Finally, those patterns are put to test on the sample robot by ADAMS(R) along with the inverse kinematics solutions and a new balance control scheme compensating for insufficient stability particulary during the initial transition period. Test results show that the robot can walk along the circular path as predicted at a resonably high speed despite the distributed mass and ground contact effects, validating effectiveness of the suggested approach.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.10
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• pp.963-968
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• 2010

This paper handles ZMP based control that is inspired by neural networks for humanoid robot walking on varying sloped surfaces. Humanoid robots are currently one of the most exciting research topics in the field of robotics, and maintaining stability while they are standing, walking or moving is a key concern. To ensure a steady and smooth walking gait of such robots, a feedforward type of neural network architecture, trained by the back propagation algorithm is employed. The inputs and outputs of the neural network architecture are the ZMPx and ZMPy errors of the robot, and the x, y positions of the robot, respectively. The neural network developed allows the controller to generate the desired balance of the robot positions, resulting in a steady gait for the robot as it moves around on a flat floor, and when it is descending slope. In this paper, experiments of humanoid robot walking are carried out, in which the actual position data from a prototype robot are measured in real time situations, and fed into a neural network inspired controller designed for stable bipedal walking.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.10
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• pp.1029-1036
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• 2011

An energy-efficient reference walking trajectory generation algorithm is suggested utilizing allowable ZMP (Zero-Moment-Point) region, which maxmizes the energy efficiency for cyclic gaits, based on three-dimensional LIPM (Linear Inverted Pendulum Model) for biped robots. As observed in natural human walking, variable ZMP manipulation is suggested, in which ZMP moves within the allowable region to reduce the joint stress (i.e., rapid acceleration and deceleration of body), and hence to reduce the consumed energy. In addition, opimization of footstep planning is conducted to decide the optimal step-length and body height for a given forward mean velocity to minimize a suitable energy performance - amount of energy required to carry a unit weight a unit distance. In this planning, in order to ensure physically realizable walking trajectory, we also considered geometrical constraints, ZMP stability condition, friction constraint, and yawing moment constraint. Simulations are performed with a 12-DOF 3D biped robot model to verify the effectiveness of the proposed method.