• Title/Summary/Keyword: Stable walking

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Optimal Joint Trajectory Generation for Biped Walking of Humanoid Robot based on Reference ZMP Trajectory (목표 ZMP 궤적 기반 휴머노이드 로봇 이족보행의 최적 관절궤적 생성)

  • Choi, Nak-Yoon;Choi, Young-Lim;Kim, Jong-Wook
    • The Journal of Korea Robotics Society
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    • v.8 no.2
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    • pp.92-103
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    • 2013
  • Humanoid robot is the most intimate robot platform suitable for human interaction and services. Biped walking is its basic locomotion method, which is performed with combination of joint actuator's rotations in the lower extremity. The present work employs humanoid robot simulator and numerical optimization method to generate optimal joint trajectories for biped walking. The simulator is developed with Matlab based on the robot structure constructed with the Denavit-Hartenberg (DH) convention. Particle swarm optimization method minimizes the cost function for biped walking associated with performance index such as altitude trajectory of clearance foot and stability index concerning zero moment point (ZMP) trajectory. In this paper, instead of checking whether ZMP's position is inside the stable region or not, reference ZMP trajectory is approximately configured with feature points by which piece-wise linear trajectory can be drawn, and difference of reference ZMP and actual one at each sampling time is added to the cost function. The optimized joint trajectories realize three phases of stable gait including initial, periodic, and final steps. For validation of the proposed approach, a small-sized humanoid robot named DARwIn-OP is commanded to walk with the optimized joint trajectories, and the walking result is successful.

Development of walking assist system for the people with lower limb-disability

  • Kim, Seok-Hwan;Izumi, Keisuke;Koujina, Yasuhiro;Ishimatsu, Takakazu
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1495-1499
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    • 2003
  • There is some equipment that helps user to exercise and to walk. But almost all equipments require some physical strength of their muscles. So we developed a system that could assist walking action of the people with lower-limb disability. The system called as walking stand adopted the balancing mechanism which assures the stable walking, and the 4 link-based mechanism that had 2 degrees of freedom on each leg. The walking stand uses four motors and has two sets of the special link-structure to simulate the human walking mechanism. With our system, even serious disabled with lower-limb disability may enjoy walking rehabilitation. And by adjusting the power, it can be used as the walking assistant mechanism instead of conventional wheelchairs. Experiments showed that our walking stand is applicable to the rehabilitation and also to the mobile device in our daily life for those people who do not have enough physical ability to walk by themselves.

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Walking Motion Planning for Quadruped Pet Robot (4족 애완로봇을 위한 보행운동 계획)

  • Yi, Soo-Yeong;Choi, Dae-Sung;Choi, Byoung-Wook
    • 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.

Development of Biped Walking Robot with Stable Walking (안정적 보행을 갖는 이족 보행 로봇의 개발)

  • Seo, Chang-Jun
    • IEMEK Journal of Embedded Systems and Applications
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    • v.3 no.2
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    • pp.82-90
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    • 2008
  • In this paper, we introduce a biped walking robot which can do static walking with 22 degree-of-freedoms. The developed biped walking robot is 480mm tall and 2500g, and is constructed by 22 RC servo motors. Before making an active algorithm, we generate the motions of robot with a motion simulator developed using C language. The two dimensional simulator is based on the inverse kinematics and D-H transform. The simulator implements various motions as we input the ankle's trajectory. Also the simulator is developed by applying the principle of inverted pendulum to acquisite the center of gravity. As we use this simulator, we can get the best appropriate angle of ankle or pelvic when the robot lifts up its one side leg during the walking. We implement the walking motions which is based on the data(angle) getting from both of simulators. The robot can be controlled by text shaped command through RF signal of wireless modem which is connected with laptop computer by serial cable.

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Quadruped Walking Control of DRC-HUBO (DRC 휴보의 4족 보행 제어)

  • Kim, Jung-Yup
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.24 no.5
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    • pp.548-552
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    • 2015
  • In this paper, we describe the quadruped walking-control algorithm of the complete full-size humanoid DARPA Robotics Challenge-HUBO (DRC-HUBO) robot. Although DRC-HUBO is a biped robot, we require a quadruped walking function using two legs and two arms to overcome uneven terrains in the DRC. We design a wave-type quadruped walking pattern as a feedforward control using several walking parameters, and we design zero moment point (ZMP) controllers to maintain stable walking using an inverted pendulum model and an observed-state feedback control scheme. In particular, we propose a switching algorithm for ZMP controllers using supporting value and weighting factors in order to maintain the ZMP control performance during foot switching. Finally, we verify the proposed algorithm by performing quadruped walking experiments using DRC-HUBO.

Hybrid Position/Force Control for Dynamic Walking of Biped Walking Robot (이족보행로봇의 동적 보행을 위한 혼합 위치/힘 제어)

  • 박인규;김진걸
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.566-569
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    • 2000
  • This hybrid position/force control for the dynamic walking of the biped robot is performed in this paper. After the biped robot was modeled with 14 degrees of freedom of the multibody dynamics, the equations of motion are constructed using velocity transformation technique. Then the inverse dynamic analysis is performed for determining the driving torques and the ground reaction forces. From this analysis, obtains the maximum ground contact force at the moment of contacting which act on the rear of the sole of swing leg and the distribution curve of the ground reaction. Because these maximum force and distribution type acts an important role to the stability of the whole dynamic walking, they are reduced and distributed smoothly by means of the trajectory of the modified ground reaction force. This new trajectory is used to the reference input for more stable dynamic walking of the whole walking region.

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Performing Missions of a Small Biped Walking Robot using Image Processing (영상 처리를 이용한 소형 이족 보행 로봇의 임무 수행)

  • Kim, Nam-Hun;Ha, Jong-Eun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.11 no.12
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    • pp.1225-1230
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    • 2016
  • This paper deals with performing missions of a small biped robot using image processing. Localization is required for stable walking under a given map. Localization of the robot is done by extracting boundary on a driving course. Estimation of three parameters including location and orientation is required when walking on a plane. In this paper, two parameters including the location of the robot along the vertical direction of robot's walking direction and an orientation is estimated for localization. Color is used for the detection of obstacles and normalized values are used for the stable detection.

A Study on Dynamic Walking Control of Biped Robot (이족 보행로봇의 동적 보행 제어에 관한 연구)

  • Shim, Byoung-Kyun;Jeong, Yang-Keun;Shim, Hyun-Seok;Lee, Woo-Song
    • Journal of the Korean Society of Industry Convergence
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    • v.17 no.4
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    • pp.245-254
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    • 2014
  • In this paper, stable and robust dynamic walking for a biped motion is proposed. To success this objective, the following structures are processed. In this paper, the proposed control method is one that adjusts actual zero moment position to move to the closest possible point in the stable area instead of following desired zero moment position. This minimizes energy consumption with the smallest joint movements. The proposed control method makes mechanical energy that drives lower limb of the bipedal robot efficient. In this paper, walking experiment is carried out with the three control structures mentioned above. The trajectory generated by off-line is illustrated by performing to walking on flat ground. experiment with an obstacle whose height is lower than that of trajectory is executed to validate dynamic motion.

Control Strategy for Modifiable Bipedal Walking on Unknown Uneven Terrain

  • Lee, Woong-Ki;Chwa, Dongkyoung;Hong, Young-Dae
    • Journal of Electrical Engineering and Technology
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    • v.11 no.6
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    • pp.1787-1792
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    • 2016
  • Previous walking pattern generation methods could generate walking patterns that allow only straight walking on flat and uneven terrain. They were unable to generate modifiable walking patterns whereby the sagittal and lateral step lengths and walking direction can be changed at every footstep. This paper proposes a novel walking pattern generation method to realize modifiable walking of humanoid robots on unknown uneven terrain. The proposed method employs a walking pattern generator based on the 3-D linear inverted pendulum model (LIPM), which enables a humanoid robot to vary its walking patterns at every footstep. A control strategy for walking on unknown uneven terrain is proposed. Virtual spring-damper (VSD) models are used to compensate for the disturbances that occur between the robot and the terrain when the robot walks on uneven terrain with unknown height. In addition, methods for generating the foot and vertical center of mass (COM) of the 3-D LIPM trajectories are developed to realize stable walking on unknown uneven terrain. The proposed method is implemented on a small-sized humanoid robot platform, DARwIn-OP and its effectiveness is demonstrated experimentally.

Effects of Step-up Training on Walking Ability of Stroke Patients by Different Support Surface Characteristics

  • Oh, Geun-Sik;Choi, Yu-Ran;Bang, Dae-Hyouk;Cha, Yong-Jun
    • Journal of the Korean Society of Physical Medicine
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    • v.12 no.3
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    • pp.99-104
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    • 2017
  • PURPOSE: Gait disturbances in patients with hemiplegic stroke involve asymmetry of stance time. Step box training is used to supplement the limitations of stair walking training and increasing the torque value of the paralyzed lower leg's strength. This study aimed to investigate whether step-up training on unstable support could change walking ability in patients with chronic stroke. METHODS: Thirty stroke patients were randomly assigned to the step-up training group (experimental group), that performed training on an unstable surface, and the control group, that performed training on a stable surface. Walking speed, step length, and cadence were measured before and after training. Paired t-tests were used to compare pre- and post-intervention data, while the independent samples t-test was used to determine intergroup differences. Values of p < .05 were considered statistically significant. RESULTS: There was a significant difference in walking ability before versus after the intervention in both groups, although the experimental group showed greater differences than the control group (walking velocity by 8.1%; step length of the non-paralyzed side by 6.9%, respectively; p<.05). CONCLUSION: Step-up training might be more effective on an unstable surface than on a stable surface for increasing walking speed and step length of the non-paralyzed side.