Experimental Study on Passive Dynamic Bipedal Walking: Comparing Test Platforms and Effects of Parameter Changes on Gait Patterns

2011 ◽  
Author(s):  
Kazi Rushdi ◽  
Derek Koop ◽  
Christine Q. Wu
Keyword(s):  
Small Difference ◽  
Bipedal Walking ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Gait Patterns ◽  
Belt Speed ◽  
Gait Parameters ◽  
Flat Feet ◽  
Walking Mechanism ◽  
Treadmill Belt

Passive dynamic walking is a gait developed, partially or in whole, by the energy provided by gravity. An improved kneed bipedal walking mechanism was designed and built to study passive gait patterns. The first aim of this study is to determine if testing a passive dynamic biped walker on a ramp is equivalent to testing on a treadmill. Based on the small difference between the gait patterns measured on the two test platforms, testing on a treadmill is equivalent to testing on a ramp. Measurement of the gait parameters were then conducted on the treadmill to evaluate the effects of the treadmill angle of inclination, mass distribution of the biped, treadmill belt speed and length of flat feet. Our experimental results are presented and compared with previous experimental and simulation results. Research on passive dynamic bipedal walking helps to develop an understanding of walking mechanics. Moreover, experimental passive dynamic walking results provide information to validate mathematical models of passive dynamic walking.

scholarly journals An experimental study of passive dynamic walking

Robotica ◽  
2004 ◽  
Vol 22 (3) ◽  
pp. 251-262 ◽  
Author(s):  
Q. Wu ◽  
N. Sabet
Keyword(s):  
Surface Friction ◽  
Step Length ◽  
Gait Pattern ◽  
Dynamic Walking ◽  
Bipedal Robots ◽  
Passive Dynamic Walking ◽  
Gait Patterns ◽  
Flat Feet ◽  
Walking Mechanism ◽  
Walking Efficiency

A two-straight-legged walking mechanism with flat feet is designed and built to study the passive dynamic gait. It is shown that the mechanism having flat feet can exhibit passive dynamic walking as those with curved feet, but the walking efficiency is significantly lower. It is also shown that the balancing mass and its orientation are effective for controlling side-to-side rocking and yaw, which have significant effects on steady walking. The effects of various parameters on the gait patterns are also studied. lt is shown that changes in the ramp angle have the most dominant effect on the gait pattern as compared with the changes in the hip mass, ramp surface friction and size of the flat feet. More specifically, as the ramp angle increases, the step length increases while the range of the side-to side rocking angle decreases and the step length dictates the walking speed and the gravitational power. Another finding, is that adding a hip mass improves the walking efficiency by allowing the mechanism to walk on a flatter ramp. This research enables us to gain a better understanding of the mechanics of walking. Such an understanding will have a direct impact on better design of prostheses and on the active control aspects of bipedal robots.

Efficient dynamic bipedal walking using effects of semicircular feet

Robotica ◽  
2010 ◽  
Vol 29 (3) ◽  
pp. 351-365 ◽  
Author(s):  
Fumihiko Asano ◽  
Zhi-Wei Luo
Keyword(s):  
Ankle Joint ◽  
High Speed ◽  
Joint Torque ◽  
Bipedal Walking ◽  
Convex Curve ◽  
Driving Mechanism ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Biped Robots ◽  
Flat Feet

SUMMARYAchieving energy-efficient and high-speed dynamic walking has become one of the main subjects of research in the area of robotic biped locomotion, and passive dynamic walking has attracted a great deal of attention as a solution to this. It is empirically known that the convex curve of the foot, which characterizes passive–dynamic walkers, has an important effect on increasing the walking speed.This paper mainly discusses our investigations into the driving mechanism for compass-like biped robots and the rolling effect of semicircular feet. We first analyze the mechanism for a planar fully actuated compass-like biped model to clarify the importance of ankle-joint torque by introducing a generalized virtual-gravity concept. A planar underactuated biped model with semicircular feet is then introduced and we demonstrate that virtual passive dynamic walking only by hip-joint torque can be accomplished based on the rolling effect. We then compare the rolling effect with a flat feet model through linear approximation, and show that the rolling effect is equivalent to virtual ankle-joint torque. Throughout this paper, we provide novel insights into how zero-moment-point-free robots can generate a dynamic bipedal gait.

Passive dynamic walking with flat feet and ankle compliance

Robotica ◽  
2009 ◽  
Vol 28 (3) ◽  
pp. 413-425 ◽  
Author(s):  
Qining Wang ◽  
Yan Huang ◽  
Long Wang
Keyword(s):  
Bipedal Walking ◽  
Knee Joints ◽  
Heel Strike ◽  
Bipedal Locomotion ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Uneven Terrain ◽  
Flat Feet ◽  
Ankle Joints ◽  
Link Model

SUMMARYThis paper presents a bipedal locomotion model for passive dynamic walking with flat feet and compliant ankles. The two-dimensional seven-link model extends the simplest walking model with the addition of hip actuation, knee joints, flat feet and torsional springs based compliance on ankle joints, concerning heel-strike and toe-strike transitions, to achieve adaptive bipedal locomotion on level ground with controllable walking speed. We investigate the effects of foot geometric parameters and ankles stiffness on bipedal walking. The model achieves satisfactory walking results not only on even ground but also on uneven terrain with no active control and on different walking velocities. In addition, from the view of stability, there is an optimal foot-ankle ratio of the passivity-based walker. The results can be used to explore further understanding of bipedal walking, and help the design of future intelligent ankle-foot prosthesis and passivity-based robot prototypes towards more practical uses.

Study of Two-Dimensional Passive Dynamic Walking Mechanism

2003 ◽  
Vol 2003.43 (0) ◽  
pp. 218-219
Author(s):  
Hiroyuki HARADA ◽  
Tadao KAGIWADA ◽  
Takumi SHIMIZU
Keyword(s):  
Two Dimensional ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Walking Mechanism

Human-like control strategy of a bipedal walking model

Robotica ◽  
2008 ◽  
Vol 26 (3) ◽  
pp. 295-306 ◽  
Author(s):  
Andrej Olenšek ◽  
Zlatko Matjačić
Keyword(s):  
Control Strategy ◽  
Control Level ◽  
Bipedal Walking ◽  
Gait Velocity ◽  
Level Control ◽  
Power Absorption ◽  
Gait Parameters ◽  
Walking Mechanism ◽  
Map Analysis ◽  
Step Control

SUMMARYThis paper presents a two-level control strategy for bipedal walking mechanism that accounts for implicit control of push-off on the between-step control level and tracking of imposed holonomic constraints on kinematic variables via feedback control on within-step control level. The proposed control strategy was tested in a biologically inspired model with minimal set of segments that allows evolution of human-like push-off and power absorption. We investigated controller's stability characteristics by using Poincaré return map analysis in eight simulation cases and further evaluated the performance of the biped walking model in terms of how variations in torso position and gait velocity relate to push-off and power absorption. The results show that the proposed control strategy, with the same set of controller's gains, enables stable walking in a variety of chosen gait parameters and can accommodate to various trunk inclinations and gait velocities in a similar way as seen in humans.

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