On the stability of algorithmic biped locomotion machines

1971 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
A.A. Frank
Keyword(s):  
Biped Locomotion ◽  
The Stability

Control of a Dynamical Biped Locomotion System for Steady Walking

1986 ◽  
Vol 108 (2) ◽  
pp. 111-118 ◽  
Author(s):  
J. Furusho ◽  
M. Masubuchi
Keyword(s):  
High Speed ◽  
Hierarchical Control ◽  
Reference Signal ◽  
Biped Locomotion ◽  
Order Model ◽  
Reduced Order ◽  
Locomotion System ◽  
Local Controller ◽  
Local Feedback ◽  
The Stability

A dynamic biped locomotion robot which realizes high speed movement is presented. Its walking cycle is about 0.45 s, its speed is about 0.8m/s, and its appearance resembles a human walking. A hierarchical control structure is adopted at the lower level at which the local feedback is implemented. The reference signal to each local controller is supplied from its higher level. The stability of steady walking is examined by using the reduced order model which has been derived by the authors and it is assured by experiments.

On the Stability of Biped Locomotion

1970 ◽  
Vol BME-17 (1) ◽  
pp. 25-36 ◽  
Author(s):  
M. Vukobratovic ◽  
A. A. Frank ◽  
D. Juricic
Keyword(s):  
Biped Locomotion ◽  
The Stability

scholarly journals Understanding the stability of deep control policies for biped locomotion

2022 ◽  
Author(s):  
Hwangpil Park ◽  
Ri Yu ◽  
Yoonsang Lee ◽  
Kyungho Lee ◽  
Jehee Lee
Keyword(s):  
Biped Locomotion ◽  
Control Policies ◽  
The Stability

Stability of biped robotic walking with frictional constraints

Robotica ◽  
2012 ◽  
Vol 31 (4) ◽  
pp. 573-588 ◽  
Author(s):  
Xuefeng Zhou ◽  
Yisheng Guan ◽  
Li Jiang ◽  
Haifei Zhu ◽  
Chuanwu Cai ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Closed Form ◽  
Contact Area ◽  
Frictional Force ◽  
Biped Robot ◽  
Biped Locomotion ◽  
Stability Criteria ◽  
Closed Form Solutions ◽  
Zero Moment ◽  
The Stability

SUMMARYTipping-over and slipping, which are related to zero moment point (ZMP) and frictional constraint respectively, are the two most common instability forms of biped robotic walking. Conventional criterion of stability is not sufficient in some cases, since it neglects frictional constraint or considers translational friction only. The goal of this paper is to fully address frictional constraints in biped walking and develop corresponding stability criteria. Frictional constraints for biped locomotion are first analyzed and then the method to obtain the closed-form solutions of the frictional force and moment for a biped robot with rectangular and circular feet is presented. The maximum frictional force and moment are calculated in the case of ZMP at the center of contact area. Experiments with a 6-degree of freedom active walking biped robot are conducted to verify the effectiveness of the stability analysis.

Measurement of robustness for biped locomotion using a linearized Poincaré map

Robotica ◽  
1996 ◽  
Vol 14 (3) ◽  
pp. 253-259 ◽  
Author(s):  
M. -Y. Cheng ◽  
C. -S. Lin
Keyword(s):  
Periodic Motion ◽  
Poincaré Map ◽  
Computational Method ◽  
Biped Locomotion ◽  
Poincare Map ◽  
The Past ◽  
Highly Nonlinear ◽  
The Stability ◽  
Linearized Model ◽  
Continuous Time System

SUMMARYMany studies on control of dynamic biped walking have been done in the past two decades. While the biped dynamics is highly nonlinear, the stability analysis, if done, is usually based on a linearized model. The validity of the linearized model may become questionable if the walking involves states that are too far away from the operating point. In this paper, an approach for evaluating the robustness based on the linearized Poincare map is suggested and examined. The Poincare map is a useful tool to investigate the periodic motion of a dynamic system. Using the Poincare“ map, one can study an associated discrete time map instead of studying the continuous time system directly. Investigation of stability of a periodic motion can be reduced to the study of the stability of a fixed point of the Poincaré map. The computational method that results in a measurement for evaluating the robustness of biped locomotion is developed. Our simulation study has verified that the suggested measurement is a good indicator.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Uniformity of Magnification from Different Electron Microscopes

1967 ◽  
Vol 25 ◽  
pp. 32-33
Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison
Keyword(s):  
Diffraction Grating ◽  
The Other ◽  
Carbon Replica ◽  
Electron Microscopes ◽  
The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

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