Dynamic balance optimization in biped robots: Physical modeling, implementation and tests using an innovative formula

Robotica ◽  
2014 ◽  
Vol 33 (10) ◽  
pp. 2083-2099 ◽  
Author(s):  
G. G. Muscolo ◽  
C. T. Recchiuto ◽  
R. Molfino
Keyword(s):  
Dynamic Balance ◽  
Center Of Mass ◽  
Analytical Formula ◽  
Humanoid Robots ◽  
Biped Robots ◽  
Target Values ◽  
Zero Moment ◽  
Torque Values ◽  
Mass Position

SUMMARYIn this paper, an analytical formula for the determination of the center of mass position in humanoid platforms is proposed and tested in a real humanoid robot. The formula uses the force-torque values obtained by the two force-torque sensors applied on the feet of the robot and the measured currents required from the motors to maintain balance as inputs. The proposed formula outputs the real center of mass position that minimizes the errors between real humanoid robots and virtual models. Data related to the Zero Moment Point positions and to the joint movements are compared with the target values, showing how the application of the proposed formula enables achieving better repeatability and predictability of the static and dynamic robot behaviour.

ZMP: A REVIEW OF SOME BASIC MISUNDERSTANDINGS

2006 ◽  
Vol 03 (02) ◽  
pp. 153-175 ◽  
Author(s):  
MIOMIR VUKOBRATOVIĆ ◽  
BRANISLAV BOROVAC ◽  
VELJKO POTKONJAK
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Balance ◽  
Decisive Role ◽  
Humanoid Robots ◽  
Ground Contact ◽  
Science And Engineering ◽  
Theoretical Assumptions ◽  
Zero Moment ◽  
Basic Characteristics

One of basic characteristics of the regular bipedal walk of humanoid robots is the maintenance of their dynamic balance during the walk, whereby a decisive role is played by the unpowered degrees of freedom arising at the foot–ground contact. Hence, the role of the Zero-Moment Point (ZMP) as an indicator of dynamic balance is indispensable. This paper gives a detailed discussion of some basic theoretical assumptions related to the ZMP in the light of imprecise, and even incorrect, interpretations that have recently appeared, and which have led to some erroneous conclusions. Examples are given to show some erroneous basic attitudes and the genesis of some of them is indicated. It is also pointed out that in the domain of bipedal walk there are still notions that are not clearly defined and their meanings differentiated in some related branches of science and engineering. One of the examples is dynamic balance and stability, which are often used interchangeably.

Biomechanics of Single Stair Climb with Implications for Inverted Pendulum Modeling

2021 ◽  
Author(s):  
Christine Buffinton ◽  
Roberta K. Blaho ◽  
Kathleen Bieryla
Keyword(s):  
Lower Limb ◽  
Inverted Pendulum ◽  
Center Of Pressure ◽  
Center Of Mass ◽  
Humanoid Robots ◽  
Single Step ◽  
Vertical Projection ◽  
Joint Kinetics ◽  
Target Values ◽  
Capture Point

Abstract Step-by-step (SBS) stair navigation is used by those with movement limitations or lower-limb prosthetics, and by humanoid robots. Knowledge of biomechanical parameters for SBS gait, however, is limited. Inverted pendulum (IP) models used to assess dynamic stability have not been applied to SBS gait. This study examined the ability of the linear inverted pendulum (LIP) model and a closed-form, variable-height inverted pendulum (VHIP) model to predict capture point stability in healthy adults executing a single stair climb. A second goal was to provide baseline kinematic and kinetic data for SBS gait. Twenty young adults executed a single step onto stairs of two heights while attached marker positions and ground reaction forces were recorded. OpenSim software determined body kinematics and joint kinetics. Trials were analyzed with LIP and VHIP models, and the predicted capture point compared to the actual center-of-pressure on the stair. Lower-limb joint moments were larger than those reported for step-over-step stair gait. Leading knee rather than trailing ankle was dominant. Center-of-mass (CoM) velocity peaked at push-off. The VHIP model accounted for only slightly more than half of the forward progression of the vertical projection of the CoM, and was not better than LIP predictions. This suggests that IP models are limited in modeling SBS gait, likely due to large hip and knee moments. The results from this study may also provide target values and strategies to aid design of lower-limb prostheses and powered exoskeletons.

Multi-level control of zero-moment point-based humanoid biped robots: a review

Robotica ◽  
2015 ◽  
Vol 34 (11) ◽  
pp. 2440-2466 ◽  
Author(s):  
Hayder F. N. Al-Shuka ◽  
B. Corves ◽  
Wen-Hong Zhu ◽  
B. Vanderborght
Keyword(s):  
Control Strategies ◽  
Humanoid Robots ◽  
Human Locomotion ◽  
Level Control ◽  
Biped Robots ◽  
Zero Moment Point ◽  
Cluttered Environments ◽  
Multi Level ◽  
Zero Moment ◽  
Autonomous Humanoid

SUMMARYResearchers dream of developing autonomous humanoid robots which behave/walk like a human being. Biped robots, although complex, have the greatest potential for use in human-centred environments such as the home or office. Studying biped robots is also important for understanding human locomotion and improving control strategies for prosthetic and orthotic limbs. Control systems of humans walking in cluttered environments are complex, however, and may involve multiple local controllers and commands from the cerebellum. Although biped robots have been of interest over the last four decades, no unified stability/balance criterion adopted for stabilization of miscellaneous walking/running modes of biped robots has so far been available. The literature is scattered and it is difficult to construct a unified background for the balance strategies of biped motion. The zero-moment point (ZMP) criterion, however, is a conservative indicator of stabilized motion for a class of biped robots. Therefore, we offer a systematic presentation of multi-level balance controllers for stabilization and balance recovery of ZMP-based humanoid robots.

On the Manipulability of the Center of Mass of Humanoid Robots: Application to Design

2010 ◽  
Author(s):  
Sebastien Cotton ◽  
Philippe Fraisse ◽  
Andrew P. Murray
Keyword(s):  
Humanoid Robot ◽  
Mechanical Design ◽  
Dynamic Balance ◽  
Center Of Mass ◽  
Humanoid Robots ◽  
Contact Forces ◽  
Joint Torque ◽  
Contact Points ◽  
Floating Base ◽  
Space Formulation

This paper proposes an analysis of the manipulability of the Center of Mass (CoM) of humanoid robots. Starting from the dynamic equations of humanoid robots, the operational space formulation is used to express the dynamics of humanoid robots at their CoM and under their specific characteristics: a free-floating base, forces at contact points, and dynamic balance constraints. After a review of the kinematic manipulability of the CoM, the concept of dynamic manipulability of the CoM is introduced. The latter represents the ability of a humanoid robot to generate a spatial motion under a stability criterion. The size and shape of the dynamic manipulability of the CoM are a function of the joint torque limitations, the contact forces and the zero moment point used as a stability criteria. Two calculations of the CoM dynamic manipulability are proposed, a fast ellipsoid approximation, and the exact polyhedron computation. A case study illustrates the proposed approach on the HOAP3 humanoid robot and its use for mechanical design optimization.

scholarly journals Calculation of the Center of Mass Position of Each Link of Multibody Biped Robots

2017 ◽  
Vol 7 (7) ◽  
pp. 724 ◽  
Author(s):  
Giovanni Muscolo ◽  
Darwin Caldwell ◽  
Ferdinando Cannella
Keyword(s):  
Center Of Mass ◽  
Biped Robots ◽  
Mass Position

scholarly journals Does the manual insertion torque of smartpegs affect the outcome of implant stability quotients (ISQ) during resonance frequency analysis (RFA)?

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Ingrid Kästel ◽  
Giles de Quincey ◽  
Jörg Neugebauer ◽  
Robert Sader ◽  
Peter Gehrke
Keyword(s):  
Resonance Frequency ◽  
Frequency Analysis ◽  
Insertion Torque ◽  
Resonance Frequency Analysis ◽  
Implant Stability ◽  
Reliable Determination ◽  
Torque Values ◽  
Finger Pressure

Abstract Background There is disagreement about the optimal torque for tightening smartpegs for resonance frequency analysis (RFA). Subjective finger pressure during hand tightening could affect the reliability of the resulting values. The aim of the current study was therefore to assess whether or not the insertion torque of a smartpeg magnetic device influences the implant stability quotient (ISQ) value during RFA. Methods Thirty self-tapping screw implants (XiVE S, Dentsply Sirona Implants, Bensheim, Germany) with a diameter of 3.8 mm and a length of 11 mm were inserted in three cow ribs with a bone quality of D1. The RFA value of each implant was measured (Ostell, FA W&H Dentalwerk, Bürmoos, Austria) in two orthogonal directions (mesial and buccal) after tightening the corresponding smartpeg type 45 with a mechanically defined value of 5 Ncm (Meg Torq device, Megagen, Daegu, South Korea) (test). Additionally, 4 different examiners measured the RFA after hand tightening the smartpegs, and the results were compared (control). Insertion torque values were determined by measuring the unscrew torque of hand seated smartpegs (Tohnichi Manufacturing Co. Ltd, Tokyo, Japan). Results The ISQ values varied from 2 to 11 Ncm by hand tightening and from 2 to 6 Ncm by machine tightening. The comparison of hand and machine tightening of smartpegs displayed only minor differences in the mean ISQ values with low standard deviations (mesial 79.76 ± 2,11, buccal 77.98 ± 2,) and no statistical difference (mesial p = 0,343 and buccal p = 0,890). Conclusions Manual tightening of smartpeg transducers allows for an objective and reliable determination of ISQ values during RFA.

scholarly journals Measuring the quartic Higgs self-coupling at a multi-TeV muon collider

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
M. Chiesa ◽  
F. Maltoni ◽  
L. Mantani ◽  
B. Mele ◽  
F. Piccinini ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Center Of Mass ◽  
Mass Energy ◽  
Simple Analysis ◽  
Proton Proton ◽  
Coupling Interaction ◽  
Center Of Mass Energy ◽  
Muon Collider ◽  
Better Than

Abstract Measuring the shape of the Higgs boson potential is of paramount importance, and will be a challenging task at current as well as future colliders. While the expectations for the measurement of the trilinear Higgs self-coupling are rather promising, an accurate measurement of the quartic self-coupling interaction is presently considered extremely challenging even at a future 100 TeV proton-proton collider. In this work we explore the sensitivity that a muon collider with a center of mass energy in the multi-TeV range and luminosities of the order of 1035cm−2s−1, as presently under discussion, might provide, thanks to a rather large three Higgs-boson production and to a limited background. By performing a first and simple analysis, we find a clear indication that a muon collider could provide a determination of the quartic Higgs self-coupling that is significantly better than what is currently considered attainable at other future colliders.

Determination of As, Cd, Ni and Pb in PM10 – comparison of different sample work-up and analysis methods/Bestimmung von As, Cd, Ni und Pb in PM10 – Vergleich verschiedener Probenaufbereitungs- und Analysenverfahren

Gefahrstoffe ◽  
2020 ◽  
Vol 80 (06) ◽  
pp. 227-233 ◽  
Author(s):  
I. Beslic ◽  
J. Burger ◽  
F. Cadoni ◽  
D. Centioli ◽  
I. Kranjc ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Metal Concentration ◽  
Inductively Coupled Plasma ◽  
Ambient Air ◽  
Power Functions ◽  
Joint Research ◽  
Inductively Coupled ◽  
Target Values ◽  
Work Up

In 2015 the European Joint Research Center (JRC) for air quality in Ispra, Italy, carried out an intercomparison for the determination of PM10 and PM2.5 in ambient air. Five laboratories also analyzed the content of heavy metals (arsenic, cadmium, lead and nickel) in PM10 from filter samples collected during the intercomparison. Thus, all steps from sampling in the field to instrumental quantification of heavy metals in the laboratory could be statistically analyzed. The different techniques of sampling and sample work-up had no significant influence on the analysis results. However, the method of instrumental analysis strongly influenced them: The results of laboratories using the Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) coincided well in most cases. For laboratories using the Energy Dispersed X-Ray Fluorescence (ED-XRF) technique the uncertainty of the results strongly depended on the metal concentration. For cadmium the concentrations generally were too low for analysis by ED-XRF, for arsenic, lead and nickel the relative uncertainties decreased exponentially with increasing concentrations. The relation between metal concentration and the relative uncertainty of analysis results could be described as power functions. Analysis of lead and nickel by ED-XRF is well possible in the range of the EU limit and target values for these metals.

scholarly journals Turning Gait Planning Method for Humanoid Robots

2018 ◽  
Vol 8 (8) ◽  
pp. 1257 ◽  
Author(s):  
Tianqi Yang ◽  
Weimin Zhang ◽  
Xuechao Chen ◽  
Zhangguo Yu ◽  
Libo Meng ◽  
...  
Keyword(s):  
Inverted Pendulum ◽  
Center Of Mass ◽  
Translational Motion ◽  
Humanoid Robots ◽  
Inverted Pendulum Model ◽  
Straight Line ◽  
Pendulum Model ◽  
The Stability ◽  
And Control ◽  
Present Simulation

The most important feature of this paper is to transform the complex motion of robot turning into a simple translational motion, thus simplifying the dynamic model. Compared with the method that generates a center of mass (COM) trajectory directly by the inverted pendulum model, this method is more precise. The non-inertial reference is introduced in the turning walk. This method can translate the turning walk into a straight-line walk when the inertial forces act on the robot. The dynamics of the robot model, called linear inverted pendulum (LIP), are changed and improved dynamics are derived to make them apply to the turning walk model. Then, we expend the new LIP model and control the zero moment point (ZMP) to guarantee the stability of the unstable parts of this model in order to generate a stable COM trajectory. We present simulation results for the improved LIP dynamics and verify the stability of the robot turning.

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