• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.6 s.249
• /
• pp.643-652
• /
• 2006

This paper is concerned with computer simulations of a biped robot walking in static and dynamic gaits. To this end, a three-dimensional robot is considered possessing a torso and two identical legs of a typical design. For such limbs, a set of inverse kinematic solutions is analytically derived between the torso and the feet. Specific walking patterns are off-line generated meeting stability based on the VPCG or ZMP condition. Subsequently, to verify whether the robot can walk as planned in the presence of mass and ground effects, a multi-body dynamics CAE code has been applied to the resulting joint motions determined by inverse kinematics. As a result, the key parameters to successful gaits could be identified including inherent characteristics as well. Upon comparisons between the two types of gaits, dynamic gaits are concluded more desirable for larger humaniods.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10a
• /
• pp.959-964
• /
• 1992

This study treats the method for kinematic modeling of the biped walking robot, for synthesizing various gait trajectories, and for calculating adequate values of the joint torque inside the stable region. To synthesize various and anthropomorphic walking easily, the gait trajectory is specified by a set of ten walking prameters, and the trunk motion equation is derived by the zero moment point and the gait trajectory. By distributing ground reaction force and moment reduced at the zero moment point to the both feet, the joint torque equation can be derived readily, and according to this equation, the joint torque to stable walking can be computed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.583-586
• /
• 2000

The conventional actuators with the speed reducer had weakness in supporting the weight of the body and leg itself. To overcome this, a new four bar link mechanism actuated by the ball screw was proposed. The four bar mechanism has higher strength and gear ratio than the conventional actuator to actutate the leg of the biped robot. One leg was designed to have ankle, thigh, and hip joints. The kinematics and dynamics of one leg with four bar link mechanism was analyzed using Euler-Lagrange approach. The dynamics of one leg was expressed in the ball strew frame.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.9
• /
• pp.886-892
• /
• 2008

In this paper, a closed-loop observer to extract the center of mass (CoM) of a bipedal robot is suggested. Comparing with the simple conversion method of just using joint angle measurements, it enables to get more reliable estimates by fusing both joint angle measurements and F/T sensor outputs at ankle joints. First, a nonlinear-type observer is constructed to estimate the flexible rotational motion of the biped in the extended Kalman filter framework. It adopts the flexible inverted pendulum model which is appropriate to address the flexible motion of bipeds, specifically in the single support phase. The predicted estimates of CoM in terms of the flexible motion observer are combined with measurements (that is, output of the CoM conversion equation with joint angles). Then, we have final CoM estimates depending on the weighting values which penalize the flexible motion model and the CoM conversion equation. Simulation results show the effectiveness of the proposed algorithm.

• Proceedings of the KIEE Conference
• /
• 2006.04a
• /
• pp.309-311
• /
• 2006

This paper aims to provide a way to improve dynamic stability of biped robots against undesirable disturbances. By using an angular velocity sensor on its shoulder, we can make a medium-sized biped robot walk stably against an impulsive disturbance. The measured signal from the sensor in used for compensating the reference angles of ankle, knee, and pelvis joints. An experiment shows that the stability of the robot is much enhanced by using a cheap sensor and simple algorithm. This kind of research helps biped robots walk more stably in real environments.

• Proceedings of the KIEE Conference
• /
• 2006.04a
• /
• pp.312-314
• /
• 2006

Researches on biped robot walking have been mostly focusing on walking on even surfaces. Therefore, robot walking has been only realized on pre-specified spaces with pre-specified movements according to the previous researches. In this paper a walking system for a biped robot using fuzzy system and neural networks to overcome those constraints. The system enables biped walking to be possible in various environments and with more complicated obstacels. For the purpose, a walking robot should recognize its surrounding environment and determine its movement. In the proposed system, a robot dynamically generates its walking trajectories of each joint by using neural networks when facing new obstacle such as stairs, and it maintains its walking stability by using closed loop fuzzy control system which manipulates the waist joints.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1675-1676
• /
• 2008

인간 동보행의 원리를 3축가속도 센서를 이용 소형 휴머노이드의 보행원리를 적용시키는 것을 목적으로 건강한 일반인 20명을 대상으로 3축가속도를 사람의 신발 앞꿈치에 장착하여 각 축에 따른 가속도를 측정하였다. 이에 앞서 사람들의 다리길이(골반부터 발목), 개인의 평균 보폭등을 측정하여 각각을 평균화하는 과정을 거치고 이 평균화된 데이터를 기준으로 제작된 소형 휴머노이드의 다리길이에 따른 보폭 및 보행원리를 적용함으로서 소형 휴머노이드의 보행을 간단한 비을 적용하여 제어할 수 있도록 하였다.

• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.343-345
• /
• 2007

This paper proposes an inertial navigation system(INS) with which a biped robot can determine his position, velocity, posture, etc. The proposed system provides the information of robots independently without using any outer signals. The defect of the algorithm is the en'or accumulation as the robot increases the mobile range. However, in this application the problem is not so critical because the working space is small and operation period of the robots is relatively short. With the proposed INS system biped robots obtain enhanced intelligence to execute their tasks. The structure and theoretical backgrounds are utilized to design the INS system. The method for application of INS system to biped robots has been illustrated.

• Proceedings of the KIEE Conference
• /
• 2002.11c
• /
• pp.169-172
• /
• 2002

This paper is concerned with walking trajectory generation by applying the genetic algorithm. The walking trajectory is generated though three via-points and genetic algorithm is employed to find velocity and acceleration at each via-point. Also genetic algorithm is applied for balancing joint trajectory. Fitness function is used for minimizing the trajectory. As a result, new algorithm generated the smooth trajectory. The proposed algorithm is verified by the experiment of biped walking robot developed in our Control laboratory, and we compared the result with the previous walking algorithm. It showed that the new proposed algorithm generated the better walking trajectory.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.343-343
• /
• 2000

The conventional actuators with the speed reducer had weakness in supporting the weight of the body and leg itself. To overcome this, a new four bar link mechanism actuated by the ball screw was proposed. Using this, we developed a new type of 10 D.O.F biped robot. The dynamics model of the biped robot is investigated in this paper. In the modeling process, the robot dynamics are expressed in the joint coordinates using the Euler-Lagrange equation. Then, they are converted in to the sliding joint coordinates, and joint torques are expressed in the force along the sliding direction of the ball screw. To test modeling of the robot, a computer simulation was performed.