Modeling and gait selection of passivity-based seven-link bipeds with dynamic series of walking phases

Robotica ◽  
2011 ◽  
Vol 30 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Yan Huang ◽  
Qining Wang ◽  
Baojun Chen ◽  
Guangming Xie ◽  
Long Wang
Keyword(s):  
Bipedal Walking ◽  
Upper Body ◽  
Dynamic Walking ◽  
Human Beings ◽  
Ankle Stiffness ◽  
Flat Feet ◽  
Ankle Joints ◽  
Walking Velocity ◽  
Motion Characteristics ◽  
Dynamic Series

SUMMARYThis paper presents a seven-link dynamic walking model that is more close to human beings than other passivity-based dynamic walking models. We add hip actuation, upper body, flat feet, and ankle joints with torsional springs to the model. Walking sequence of flat-feet walkers has several substreams, which forms bipedal walking with dynamic series of phases. We investigate the effects of ankle stiffness on gait selection and evaluate different gaits in walking velocity, efficiency, and stability. Experimental results indicate that ankle stiffness plays different roles in different gaits and the gaits, which are more close to human walking with moderate speed, achieve better motion characteristics.

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.

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.

THREE ADDITIONS TO PASSIVE DYNAMIC WALKING: ACTUATION, AN UPPER BODY, AND 3D STABILITY

2005 ◽  
Vol 02 (04) ◽  
pp. 459-478 ◽  
Author(s):  
MARTIJN WISSE
Keyword(s):  
Simulation Models ◽  
Human Locomotion ◽  
Upper Body ◽  
Walking Robots ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Kinematic Coupling ◽  
Ankle Joints ◽  
Stable Gait ◽  
Static Form

One of the main challenges in the design of human-like walking robots (useful for service or entertainment applications as well as the study of human locomotion) is to obtain dynamic locomotion, as opposed to the static form of locomotion demonstrated by most of the current prototypes. A promising concept is the idea of passive dynamic walking; even completely unactuated and uncontrolled mechanisms can perform a stable gait when walking down a shallow slope. This concept enables the construction of dynamically walking prototypes that are simpler yet more natural in their motions than the static bipeds. This paper presents three additions to the concept of passive dynamic walking. First, hip actuation is added to increase the fore-aft stability and to provide power to the system, removing the need for a downhill floor. Second, a bisecting hip mechanism is introduced to allow the addition of a passive upper body without compromising the simplicity, efficiency and naturalness of the concept of passive dynamic walking. Third, skateboard-like ankle joints are implemented to provide 3D stability. These ankles couple the unstable sideways lean motion to yaw (steering), a kinematic coupling which provides sideways stability when walking with sufficient forward velocity. The three additions are investigated both with elementary simulation models and with prototype experiments. All three prototypes demonstrate an uncannily natural and stable gait while requiring only two foot switches and three on/off actuators.

scholarly journals Virtual Slope Control of a Forward Dynamic Bipedal Walker

2005 ◽  
Vol 127 (1) ◽  
pp. 114-122 ◽  
Author(s):  
S. Russell ◽  
K. P. Granata ◽  
P. Sheth
Keyword(s):  
Primary Source ◽  
Bipedal Walking ◽  
Stable Steady State ◽  
Dynamic Walking ◽  
Active Joint ◽  
Joint Torques ◽  
Power And Control ◽  
Stable Performance ◽  
Walking Velocity ◽  
Downhill Walking

Active joint torques are the primary source of power and control in dynamic walking motion. However the amplitude, rate, timing and phasic behavior of the joint torques necessary to achieve a natural and stable performance are difficult to establish. The goal of this study was to demonstrate the feasibility and stable behavior of an actively controlled bipedal walking simulation wherein the natural system dynamics were preserved by an active, nonlinear, state-feedback controller patterned after passive downhill walking. A two degree-of-freedom, forward-dynamic simulation was implemented with active joint torques applied at the hip joints and stance leg ankle. Kinematic trajectories produced by the active walker were similar to passive dynamic walking with active joint torques influenced by prescribed walking velocity. The control resulted in stable steady-state gait patterns, i.e. eigenvalue magnitudes of the stride function were less than one. The controller coefficient analogous to the virtual slope was modified to successfully control average walking velocity. Furture developments are necessary to expand the range of walking velocities.

Ankle Joints and Flat Feet in Dynamic Walking

2005 ◽  
pp. 787-800 ◽  
Author(s):  
Daan G.E. Hobbelen ◽  
Martijn Wisse
Keyword(s):  
Dynamic Walking ◽  
Flat Feet ◽  
Ankle Joints

EFFECTS OF FOOT SHAPE ON ENERGETIC EFFICIENCY AND DYNAMIC STABILITY OF PASSIVE DYNAMIC BIPED WITH UPPER BODY

2010 ◽  
Vol 07 (02) ◽  
pp. 295-313 ◽  
Author(s):  
QINING WANG ◽  
YAN HUANG ◽  
JINYING ZHU ◽  
LONG WANG ◽  
DONGJIAO LV
Keyword(s):  
Dynamic Stability ◽  
Computer Simulations ◽  
Upper Body ◽  
Human Gait ◽  
Energetic Efficiency ◽  
Dynamic Walking ◽  
Passive Dynamic Walking ◽  
Flat Feet ◽  
Simulation Results

Passive dynamic walking has been developed as a possible explanation for the efficiency of the human gait. In this paper, we investigate the effects of foot shape on energetic efficiency and dynamic stability of passivity-based bipeds with upper body. Three walking models with point feet, round feet and flat feet were presented. Each model has an upper body constrained to keep midway between legs. We use computer simulations to find which foot shapes are indeed optimal in view of energetic efficiency and dynamic stability for a passive dynamic biped with upper body. Simulation results indicate that feet improve both the energetic efficiency and dynamic stability of passive dynamic bipeds.

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.

Effects of a Passive Dynamic Walker’s Mechanical Parameters on Foot-Ground Clearance

2014 ◽  
Vol 687-691 ◽  
pp. 279-284
Author(s):  
Xin Yu Liu ◽  
Xi Zhe Zang ◽  
Jie Zhao
Keyword(s):  
Stability Analysis ◽  
Numerical Simulations ◽  
Hip Joint ◽  
Parameters Optimization ◽  
Knee Joints ◽  
Upper Body ◽  
Mechanical Parameters ◽  
Human Beings ◽  
Ground Clearance ◽  
Ankle Joints

Unlike human beings, a robot will fall without a sufficient walking foot-ground clearance, which is essential to a success walking. However, to obtain less calculating time and simpler analysis, foot scuffing is ignored in most studies during numerical simulations of passive dynamic walkers which can walk down a gentle slope and are actuated only by their own gravity. So this paper initials a study on the effects of a passive dynamic walker’s mechanical parameters on foot-ground clearance and the results can be used to make a further parameters optimization based on walking stability analysis. A passive dynamic walking model with a hip joint, knee joints, ankle joints and an upper body and a prototype were built and numerical simulations were implemented to analyze the effects of mechanical parameters on foot-ground clearance. Finally, the results were validated in prototype experiments.

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