Biped gait generation based on parametric excitation by knee-joint actuation

Robotica ◽  
2009 ◽  
Vol 27 (7) ◽  
pp. 1063-1073 ◽  
Author(s):  
Yuji Harata ◽  
Fumihiko Asano ◽  
Zhi-Wei Luo ◽  
Kouichi Taji ◽  
Yoji Uno
Keyword(s):  
Parametric Excitation ◽  
Mechanical Energy ◽  
Biped Robot ◽  
Bipedal Walking ◽  
Reference Trajectory ◽  
Gait Generation ◽  
Total Mechanical Energy ◽  
Walking Performance ◽  
Excitation Mechanisms ◽  
Telescopic Legs

SUMMARYRestoration of mechanical energy dissipating on impact at the ground is necessary for sustainable gait generation. Parametric excitation is one approach to restore the mechanical energy. Asano et al. (“Parametric excitation mechanisms for dynamic bipedal walking,” IEEE International Conference on Robotics and Automation (2005) pp. 611–617.) applied parametric excitation to a biped robot with telescopic-legs, in which up-and-down motion restores total mechanical energy like playing on the swing. In this paper, parametric excitation principle is applied to a kneed biped robot with only knee actuation and it is shown that the robot walks successively without hip actuation. We also examine influences of several parameters and reference trajectory on walking performance.

An optimization method for the reference trajectory of parametric excitation walking

Robotica ◽  
2010 ◽  
Vol 29 (4) ◽  
pp. 585-593 ◽  
Author(s):  
Kouichi Taji ◽  
Yoshihisa Banno ◽  
Yuji Harata
Keyword(s):  
Parametric Excitation ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Biped Robot ◽  
Optimization Method ◽  
Search Method ◽  
Walking Ability ◽  
Reference Trajectory ◽  
Spline Curves ◽  
Walking Performance

SUMMARYIn parametric excitation walking, up-and-down motion of the center of mass restores mechanical energy and sustainable gait is generated. Not only walking performance but also walking ability strongly depends on the reference trajectory of the center of mass. In this paper, we propose an optimization method for the reference trajectory, in which the reference trajectory is confined to the quartic spline curves and the parameters of spline curves are optimized by a local search method usually used in combinatorial optimization. We apply the proposed method to a kneed biped robot and find some remarkably interesting results by numerical simulations.

scholarly journals Parametric excitation-based inverse bending gait generation

Robotica ◽  
2011 ◽  
Vol 29 (6) ◽  
pp. 831-841 ◽  
Author(s):  
Yuji Harata ◽  
Fumihiko Asano ◽  
Kouichi Taji ◽  
Yoji Uno
Keyword(s):  
Kinetic Energy ◽  
Parametric Excitation ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Biped Robot ◽  
Heel Strike ◽  
Gait Generation ◽  
Forward Bending

SUMMARYIn a gait generation method based on the parametric excitation principle, appropriate motion of the center of mass restores kinetic energy lost by heel strike. The motion is realized by bending and stretching a swing-leg regardless of bending direction. In this paper, we first show that inverse bending restores more mechanical energy than forward bending, and then propose a parametric excitation-based inverse bending gait for a kneed biped robot, which improves gait efficiency of parametric excitation walking.

scholarly journals A biomechanical study of load carriage by two paired subjects in response to increased load mass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guillaume Fumery ◽  
Nicolas A. Turpin ◽  
Laetitia Claverie ◽  
Vincent Fourcassié ◽  
Pierre Moretto
Keyword(s):  
Recovery Rate ◽  
Energy Recovery ◽  
Mechanical Energy ◽  
Center Of Mass ◽  
Step Length ◽  
Biomechanical Study ◽  
Load Carriage ◽  
Joint Torque ◽  
Total Mechanical Energy ◽  
Load Mass

AbstractThe biomechanics of load carriage has been studied extensively with regards to single individuals, yet not so much with regards to collective transport. We investigated the biomechanics of walking in 10 paired individuals carrying a load that represented 20%, 30%, or 40% of the aggregated body-masses. We computed the energy recovery rate at the center of mass of the system consisting of the two individuals plus the carried load in order to test to what extent the pendulum-like behavior and the economy of the gait were affected. Joint torque was also computed to investigate the intra- and inter-subject strategies occurring in response to this. The ability of the subjects to move the whole system like a pendulum appeared rendered obvious through shortened step length and lowered vertical displacements at the center of mass of the system, while energy recovery rate and total mechanical energy remained constant. In parallel, an asymmetry of joint moment vertical amplitude and coupling among individuals in all pairs suggested the emergence of a leader/follower schema. Beyond the 30% threshold of increased load mass, the constraints at the joint level were balanced among individuals leading to a degraded pendulum-like behavior.

Vibration suppression and energy transfer by parametric excitation in drive systems

2012 ◽  
Vol 226 (8) ◽  
pp. 2000-2014 ◽  
Author(s):  
Horst Ecker ◽  
Thomas Pumhössel
Keyword(s):  
Energy Transfer ◽  
Parametric Excitation ◽  
Vibration Suppression ◽  
Negative Impact ◽  
Energy Transfer Mechanism ◽  
Engineering Systems ◽  
Excitation Mechanism ◽  
Electrical Drive ◽  
Excitation Mechanisms ◽  
Drive Systems

Drive systems may experience torsional vibrations due to various kinds of excitation mechanisms. In many engineering systems, however, such vibrations may have a negative impact on the performance and must be avoided or reduced to an acceptable level by all means. Self-excited vibrations are especially unwanted, since they may grow rapidly and not only degrade the performance but even damage machinery. In this contribution it is suggested to employ parametric stiffness excitation to suppress self-excited vibrations. In the first part of the article we study the basic energy transfer mechanism that is initiated by parametric excitation, and some general conclusions are drawn. In the second part, a hypothetic drivetrain, consisting of an electrical motor, a drive shaft and working rolls is investigated. A self-excitation mechanism is assumed to destabilize the drive system. Parametric excitation is introduced via the speed control of the electrical drive, and the capability of stabilizing the system by this measure is investigated. It is shown that the damping available in the system can be used much more effectively if parametric stiffness excitation is employed.

NHE-1 participates in isoproterenol-induced downregulation of SERCA2a and development of cardiac remodeling in rat hearts

2011 ◽  
Vol 301 (5) ◽  
pp. H2154-H2160 ◽  
Author(s):  
Munetaka Shibata ◽  
Daisuke Takeshita ◽  
Koji Obata ◽  
Shinichi Mitsuyama ◽  
Haruo Ito ◽  
...  
Keyword(s):  
Body Weight ◽  
Cardiac Hypertrophy ◽  
Cardiac Remodeling ◽  
Mechanical Energy ◽  
Systolic Pressure ◽  
Beneficial Effects ◽  
Rat Hearts ◽  
Total Mechanical Energy ◽  
Male Wistar Rats ◽  
Lv Volume

Impaired Ca2+ handling is one of the main characteristics in heart failure patients. Recently, we reported abnormal expressions of Ca2+-handling proteins in isoproterenol (ISO)-induced hypertrophied rat hearts. On the other hand, Na+/H+ exchanger (NHE)-1 inhibitor has been demonstrated to exert beneficial effects in ischemic-reperfusion injury and in the development of cardiac remodeling. The aims of the present study are to investigate the role of NHE-1 on Ca2+ handling and development of cardiac hypertrophy in ISO-infused rats. Male Wistar rats were randomly divided into vehicle [control (CTL)] and ISO groups without or with pretreatment with a selective NHE-1 inhibitor, BIIB-723. ISO infusion for 1 wk significantly increased the ratios of heart to body weight and left ventricle (LV) to body weight and collagen accumulation. All of these increases were antagonized by coadministration with BIIB-723. The ISO-induced significant increase in LV wall thickness was suppressed significantly ( P < 0.05) by BIIB-723. ISO-induced decreases in cardiac stroke volume and a total mechanical energy per beat index, systolic pressure-volume area at midrange LV volume, were normalized by BIIB-723. The markedly higher expression of NHE-1 protein in the ISO group than that in CTL group was suppressed ( P < 0.05) by BIIB-723. Surprisingly, ISO induced downregulation of the important Ca2+-handling protein sarcoplasmic reticulum Ca2+-ATPase 2a, the expression of which was also normalized by BIIB-723 without changes in phosphorylated phospholamban (PLB)/PLB expression. We conclude that NHE-1 contributes to ISO-induced abnormal Ca2+ handling associated with cardiac hypertrophy. Inhibition of NHE-1 ameliorates cardiac Ca2+-handling impairment and prevents the development of cardiac dysfunction in ISO-infused rats.

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